Commit | Line | Data |
---|---|---|
e53dd083 MCC |
1 | Kernel Parameters |
2 | ~~~~~~~~~~~~~~~~~ | |
1da177e4 LT |
3 | |
4 | The following is a consolidated list of the kernel parameters as implemented | |
5 | (mostly) by the __setup() macro and sorted into English Dictionary order | |
6 | (defined as ignoring all punctuation and sorting digits before letters in a | |
7 | case insensitive manner), and with descriptions where known. | |
8 | ||
9 | Module parameters for loadable modules are specified only as the | |
10 | parameter name with optional '=' and value as appropriate, such as: | |
11 | ||
12 | modprobe usbcore blinkenlights=1 | |
13 | ||
14 | Module parameters for modules that are built into the kernel image | |
15 | are specified on the kernel command line with the module name plus | |
16 | '.' plus parameter name, with '=' and value if appropriate, such as: | |
17 | ||
18 | usbcore.blinkenlights=1 | |
19 | ||
ca1eda2d RD |
20 | Hyphens (dashes) and underscores are equivalent in parameter names, so |
21 | log_buf_len=1M print-fatal-signals=1 | |
22 | can also be entered as | |
23 | log-buf-len=1M print_fatal_signals=1 | |
24 | ||
25 | ||
a901ebb9 SR |
26 | This document may not be entirely up to date and comprehensive. The command |
27 | "modinfo -p ${modulename}" shows a current list of all parameters of a loadable | |
28 | module. Loadable modules, after being loaded into the running kernel, also | |
29 | reveal their parameters in /sys/module/${modulename}/parameters/. Some of these | |
30 | parameters may be changed at runtime by the command | |
31 | "echo -n ${value} > /sys/module/${modulename}/parameters/${parm}". | |
32 | ||
6585fa8a SR |
33 | The parameters listed below are only valid if certain kernel build options were |
34 | enabled and if respective hardware is present. The text in square brackets at | |
35 | the beginning of each description states the restrictions within which a | |
36 | parameter is applicable: | |
1da177e4 LT |
37 | |
38 | ACPI ACPI support is enabled. | |
c99c108a | 39 | AGP AGP (Accelerated Graphics Port) is enabled. |
1da177e4 LT |
40 | ALSA ALSA sound support is enabled. |
41 | APIC APIC support is enabled. | |
42 | APM Advanced Power Management support is enabled. | |
e7ba176b | 43 | AVR32 AVR32 architecture is enabled. |
1da177e4 | 44 | AX25 Appropriate AX.25 support is enabled. |
0ae53640 | 45 | BLACKFIN Blackfin architecture is enabled. |
a9913044 | 46 | DRM Direct Rendering Management support is enabled. |
1da177e4 LT |
47 | EDD BIOS Enhanced Disk Drive Services (EDD) is enabled |
48 | EFI EFI Partitioning (GPT) is enabled | |
49 | EIDE EIDE/ATAPI support is enabled. | |
50 | FB The frame buffer device is enabled. | |
2521f2c2 | 51 | GCOV GCOV profiling is enabled. |
1da177e4 | 52 | HW Appropriate hardware is enabled. |
1da177e4 | 53 | IA-64 IA-64 architecture is enabled. |
6146f0d5 | 54 | IMA Integrity measurement architecture is enabled. |
1da177e4 | 55 | IOSCHED More than one I/O scheduler is enabled. |
41e2e8be | 56 | IP_PNP IP DHCP, BOOTP, or RARP is enabled. |
b0f83b28 | 57 | IPV6 IPv6 support is enabled. |
1da177e4 LT |
58 | ISAPNP ISA PnP code is enabled. |
59 | ISDN Appropriate ISDN support is enabled. | |
60 | JOY Appropriate joystick support is enabled. | |
84c08fd6 | 61 | KGDB Kernel debugger support is enabled. |
fef07aae | 62 | KVM Kernel Virtual Machine support is enabled. |
11ef697b | 63 | LIBATA Libata driver is enabled |
1da177e4 LT |
64 | LP Printer support is enabled. |
65 | LOOP Loopback device support is enabled. | |
66 | M68k M68k architecture is enabled. | |
67 | These options have more detailed description inside of | |
68 | Documentation/m68k/kernel-options.txt. | |
69 | MCA MCA bus support is enabled. | |
70 | MDA MDA console support is enabled. | |
71 | MOUSE Appropriate mouse support is enabled. | |
309e57df | 72 | MSI Message Signaled Interrupts (PCI). |
c8facbb6 | 73 | MTD MTD (Memory Technology Device) support is enabled. |
1da177e4 LT |
74 | NET Appropriate network support is enabled. |
75 | NUMA NUMA support is enabled. | |
734efb46 | 76 | GENERIC_TIME The generic timeofday code is enabled. |
1da177e4 LT |
77 | NFS Appropriate NFS support is enabled. |
78 | OSS OSS sound support is enabled. | |
c8facbb6 RD |
79 | PV_OPS A paravirtualized kernel is enabled. |
80 | PARIDE The ParIDE (parallel port IDE) subsystem is enabled. | |
1da177e4 LT |
81 | PARISC The PA-RISC architecture is enabled. |
82 | PCI PCI bus support is enabled. | |
7f785763 | 83 | PCIE PCI Express support is enabled. |
1da177e4 LT |
84 | PCMCIA The PCMCIA subsystem is enabled. |
85 | PNP Plug & Play support is enabled. | |
86 | PPC PowerPC architecture is enabled. | |
87 | PPT Parallel port support is enabled. | |
88 | PS2 Appropriate PS/2 support is enabled. | |
89 | RAM RAM disk support is enabled. | |
90 | S390 S390 architecture is enabled. | |
91 | SCSI Appropriate SCSI support is enabled. | |
92 | A lot of drivers has their options described inside of | |
93 | Documentation/scsi/. | |
20510f2f | 94 | SECURITY Different security models are enabled. |
1da177e4 LT |
95 | SELINUX SELinux support is enabled. |
96 | SERIAL Serial support is enabled. | |
e523d93c | 97 | SH SuperH architecture is enabled. |
1da177e4 LT |
98 | SMP The kernel is an SMP kernel. |
99 | SPARC Sparc architecture is enabled. | |
77437fd4 DB |
100 | SWSUSP Software suspend (hibernation) is enabled. |
101 | SUSPEND System suspend states are enabled. | |
f38f1d2a | 102 | FTRACE Function tracing enabled. |
225a9be2 | 103 | TPM TPM drivers are enabled. |
1da177e4 | 104 | TS Appropriate touchscreen support is enabled. |
d4f373e5 | 105 | UMS USB Mass Storage support is enabled. |
1da177e4 LT |
106 | USB USB support is enabled. |
107 | USBHID USB Human Interface Device support is enabled. | |
108 | V4L Video For Linux support is enabled. | |
109 | VGA The VGA console has been enabled. | |
110 | VT Virtual terminal support is enabled. | |
111 | WDT Watchdog support is enabled. | |
112 | XT IBM PC/XT MFM hard disk support is enabled. | |
cd4f0ef7 | 113 | X86-32 X86-32, aka i386 architecture is enabled. |
1da177e4 LT |
114 | X86-64 X86-64 architecture is enabled. |
115 | More X86-64 boot options can be found in | |
71cced6e | 116 | Documentation/x86/x86_64/boot-options.txt . |
c0115606 | 117 | X86 Either 32bit or 64bit x86 (same as X86-32+X86-64) |
c1c5413a | 118 | XEN Xen support is enabled |
1da177e4 LT |
119 | |
120 | In addition, the following text indicates that the option: | |
121 | ||
122 | BUGS= Relates to possible processor bugs on the said processor. | |
123 | KNL Is a kernel start-up parameter. | |
124 | BOOT Is a boot loader parameter. | |
125 | ||
126 | Parameters denoted with BOOT are actually interpreted by the boot | |
127 | loader, and have no meaning to the kernel directly. | |
128 | Do not modify the syntax of boot loader parameters without extreme | |
954a8b81 | 129 | need or coordination with <Documentation/x86/boot.txt>. |
1da177e4 | 130 | |
5558870b | 131 | There are also arch-specific kernel-parameters not documented here. |
71cced6e | 132 | See for example <Documentation/x86/x86_64/boot-options.txt>. |
5558870b | 133 | |
1da177e4 LT |
134 | Note that ALL kernel parameters listed below are CASE SENSITIVE, and that |
135 | a trailing = on the name of any parameter states that that parameter will | |
136 | be entered as an environment variable, whereas its absence indicates that | |
137 | it will appear as a kernel argument readable via /proc/cmdline by programs | |
138 | running once the system is up. | |
139 | ||
9c4751fd | 140 | The number of kernel parameters is not limited, but the length of the |
141 | complete command line (parameters including spaces etc.) is limited to | |
142 | a fixed number of characters. This limit depends on the architecture | |
143 | and is between 256 and 4096 characters. It is defined in the file | |
144 | ./include/asm/setup.h as COMMAND_LINE_SIZE. | |
145 | ||
146 | ||
6cececfc | 147 | acpi= [HW,ACPI,X86] |
03d926f8 | 148 | Advanced Configuration and Power Interface |
68ca4069 | 149 | Format: { force | off | strict | noirq | rsdt } |
1da177e4 LT |
150 | force -- enable ACPI if default was off |
151 | off -- disable ACPI if default was on | |
152 | noirq -- do not use ACPI for IRQ routing | |
a9913044 | 153 | strict -- Be less tolerant of platforms that are not |
1da177e4 | 154 | strictly ACPI specification compliant. |
237889bf | 155 | rsdt -- prefer RSDT over (default) XSDT |
aa2110cb | 156 | copy_dsdt -- copy DSDT to memory |
1da177e4 | 157 | |
53471121 | 158 | See also Documentation/power/pm.txt, pci=noacpi |
1da177e4 | 159 | |
a1fdcc0d LB |
160 | acpi_apic_instance= [ACPI, IOAPIC] |
161 | Format: <int> | |
162 | 2: use 2nd APIC table, if available | |
163 | 1,0: use 1st APIC table | |
4e381a4f | 164 | default: 0 |
a1fdcc0d | 165 | |
c3d6de69 TR |
166 | acpi_backlight= [HW,ACPI] |
167 | acpi_backlight=vendor | |
168 | acpi_backlight=video | |
169 | If set to vendor, prefer vendor specific driver | |
170 | (e.g. thinkpad_acpi, sony_acpi, etc.) instead | |
171 | of the ACPI video.ko driver. | |
172 | ||
a0d84a92 BH |
173 | acpi.debug_layer= [HW,ACPI,ACPI_DEBUG] |
174 | acpi.debug_level= [HW,ACPI,ACPI_DEBUG] | |
1da177e4 | 175 | Format: <int> |
a0d84a92 BH |
176 | CONFIG_ACPI_DEBUG must be enabled to produce any ACPI |
177 | debug output. Bits in debug_layer correspond to a | |
178 | _COMPONENT in an ACPI source file, e.g., | |
179 | #define _COMPONENT ACPI_PCI_COMPONENT | |
180 | Bits in debug_level correspond to a level in | |
181 | ACPI_DEBUG_PRINT statements, e.g., | |
182 | ACPI_DEBUG_PRINT((ACPI_DB_INFO, ... | |
e76f4276 BH |
183 | The debug_level mask defaults to "info". See |
184 | Documentation/acpi/debug.txt for more information about | |
185 | debug layers and levels. | |
a0d84a92 | 186 | |
e76f4276 BH |
187 | Enable processor driver info messages: |
188 | acpi.debug_layer=0x20000000 | |
189 | Enable PCI/PCI interrupt routing info messages: | |
190 | acpi.debug_layer=0x400000 | |
a0d84a92 BH |
191 | Enable AML "Debug" output, i.e., stores to the Debug |
192 | object while interpreting AML: | |
193 | acpi.debug_layer=0xffffffff acpi.debug_level=0x2 | |
a0d84a92 BH |
194 | Enable all messages related to ACPI hardware: |
195 | acpi.debug_layer=0x2 acpi.debug_level=0xffffffff | |
196 | ||
197 | Some values produce so much output that the system is | |
198 | unusable. The "log_buf_len" parameter may be useful | |
199 | if you need to capture more output. | |
f989106c | 200 | |
0cb55ad2 RD |
201 | acpi_display_output= [HW,ACPI] |
202 | acpi_display_output=vendor | |
203 | acpi_display_output=video | |
204 | See above. | |
205 | ||
206 | acpi_irq_balance [HW,ACPI] | |
207 | ACPI will balance active IRQs | |
208 | default in APIC mode | |
209 | ||
210 | acpi_irq_nobalance [HW,ACPI] | |
211 | ACPI will not move active IRQs (default) | |
212 | default in PIC mode | |
213 | ||
214 | acpi_irq_isa= [HW,ACPI] If irq_balance, mark listed IRQs used by ISA | |
215 | Format: <irq>,<irq>... | |
216 | ||
217 | acpi_irq_pci= [HW,ACPI] If irq_balance, clear listed IRQs for | |
218 | use by PCI | |
219 | Format: <irq>,<irq>... | |
220 | ||
221 | acpi_no_auto_ssdt [HW,ACPI] Disable automatic loading of SSDT | |
222 | ||
223 | acpi_os_name= [HW,ACPI] Tell ACPI BIOS the name of the OS | |
224 | Format: To spoof as Windows 98: ="Microsoft Windows" | |
225 | ||
226 | acpi_osi= [HW,ACPI] Modify list of supported OS interface strings | |
227 | acpi_osi="string1" # add string1 -- only one string | |
228 | acpi_osi="!string2" # remove built-in string2 | |
229 | acpi_osi= # disable all strings | |
230 | ||
6cececfc | 231 | acpi_pm_good [X86] |
0cb55ad2 RD |
232 | Override the pmtimer bug detection: force the kernel |
233 | to assume that this machine's pmtimer latches its value | |
234 | and always returns good values. | |
235 | ||
4af94f39 RD |
236 | acpi_sci= [HW,ACPI] ACPI System Control Interrupt trigger mode |
237 | Format: { level | edge | high | low } | |
238 | ||
239 | acpi_serialize [HW,ACPI] force serialization of AML methods | |
240 | ||
241 | acpi_skip_timer_override [HW,ACPI] | |
242 | Recognize and ignore IRQ0/pin2 Interrupt Override. | |
243 | For broken nForce2 BIOS resulting in XT-PIC timer. | |
244 | ||
245 | acpi_sleep= [HW,ACPI] Sleep options | |
246 | Format: { s3_bios, s3_mode, s3_beep, s4_nohwsig, | |
d7f0eea9 | 247 | old_ordering, s4_nonvs, sci_force_enable } |
4af94f39 RD |
248 | See Documentation/power/video.txt for information on |
249 | s3_bios and s3_mode. | |
250 | s3_beep is for debugging; it makes the PC's speaker beep | |
251 | as soon as the kernel's real-mode entry point is called. | |
252 | s4_nohwsig prevents ACPI hardware signature from being | |
253 | used during resume from hibernation. | |
254 | old_ordering causes the ACPI 1.0 ordering of the _PTS | |
255 | control method, with respect to putting devices into | |
256 | low power states, to be enforced (the ACPI 2.0 ordering | |
257 | of _PTS is used by default). | |
258 | s4_nonvs prevents the kernel from saving/restoring the | |
259 | ACPI NVS memory during hibernation. | |
d7f0eea9 ZR |
260 | sci_force_enable causes the kernel to set SCI_EN directly |
261 | on resume from S1/S3 (which is against the ACPI spec, | |
262 | but some broken systems don't work without it). | |
4af94f39 RD |
263 | |
264 | acpi_use_timer_override [HW,ACPI] | |
265 | Use timer override. For some broken Nvidia NF5 boards | |
266 | that require a timer override, but don't have HPET | |
267 | ||
7e90560c LT |
268 | acpi_enforce_resources= [ACPI] |
269 | { strict | lax | no } | |
270 | Check for resource conflicts between native drivers | |
271 | and ACPI OperationRegions (SystemIO and SystemMemory | |
272 | only). IO ports and memory declared in ACPI might be | |
273 | used by the ACPI subsystem in arbitrary AML code and | |
274 | can interfere with legacy drivers. | |
275 | strict (default): access to resources claimed by ACPI | |
276 | is denied; legacy drivers trying to access reserved | |
277 | resources will fail to bind to device using them. | |
278 | lax: access to resources claimed by ACPI is allowed; | |
279 | legacy drivers trying to access reserved resources | |
280 | will bind successfully but a warning message is logged. | |
281 | no: ACPI OperationRegions are not marked as reserved, | |
282 | no further checks are performed. | |
283 | ||
1da177e4 LT |
284 | ad1848= [HW,OSS] |
285 | Format: <io>,<irq>,<dma>,<dma2>,<type> | |
286 | ||
4af94f39 RD |
287 | add_efi_memmap [EFI; X86] Include EFI memory map in |
288 | kernel's map of available physical RAM. | |
289 | ||
1da177e4 LT |
290 | advansys= [HW,SCSI] |
291 | See header of drivers/scsi/advansys.c. | |
292 | ||
1da177e4 LT |
293 | aedsp16= [HW,OSS] Audio Excel DSP 16 |
294 | Format: <io>,<irq>,<dma>,<mss_io>,<mpu_io>,<mpu_irq> | |
295 | See also header of sound/oss/aedsp16.c. | |
a9913044 | 296 | |
0cb55ad2 RD |
297 | agp= [AGP] |
298 | { off | try_unsupported } | |
299 | off: disable AGP support | |
300 | try_unsupported: try to drive unsupported chipsets | |
301 | (may crash computer or cause data corruption) | |
302 | ||
1da177e4 LT |
303 | aha152x= [HW,SCSI] |
304 | See Documentation/scsi/aha152x.txt. | |
305 | ||
306 | aha1542= [HW,SCSI] | |
307 | Format: <portbase>[,<buson>,<busoff>[,<dmaspeed>]] | |
308 | ||
309 | aic7xxx= [HW,SCSI] | |
310 | See Documentation/scsi/aic7xxx.txt. | |
311 | ||
312 | aic79xx= [HW,SCSI] | |
313 | See Documentation/scsi/aic79xx.txt. | |
314 | ||
d944d549 RK |
315 | alignment= [KNL,ARM] |
316 | Allow the default userspace alignment fault handler | |
317 | behaviour to be specified. Bit 0 enables warnings, | |
318 | bit 1 enables fixups, and bit 2 sends a segfault. | |
319 | ||
54b4cbd2 JR |
320 | amd_iommu= [HW,X86-84] |
321 | Pass parameters to the AMD IOMMU driver in the system. | |
322 | Possible values are: | |
afa9fdc2 FT |
323 | fullflush - enable flushing of IO/TLB entries when |
324 | they are unmapped. Otherwise they are | |
325 | flushed before they will be reused, which | |
326 | is a lot of faster | |
a5235725 JR |
327 | off - do not initialize any AMD IOMMU found in |
328 | the system | |
afa9fdc2 | 329 | |
1da177e4 LT |
330 | amijoy.map= [HW,JOY] Amiga joystick support |
331 | Map of devices attached to JOY0DAT and JOY1DAT | |
332 | Format: <a>,<b> | |
333 | See also Documentation/kernel/input/joystick.txt | |
334 | ||
335 | analog.map= [HW,JOY] Analog joystick and gamepad support | |
336 | Specifies type or capabilities of an analog joystick | |
337 | connected to one of 16 gameports | |
338 | Format: <type1>,<type2>,..<type16> | |
339 | ||
a9913044 RD |
340 | apc= [HW,SPARC] |
341 | Power management functions (SPARCstation-4/5 + deriv.) | |
1da177e4 LT |
342 | Format: noidle |
343 | Disable APC CPU standby support. SPARCstation-Fox does | |
344 | not play well with APC CPU idle - disable it if you have | |
345 | APC and your system crashes randomly. | |
346 | ||
ca1eda2d | 347 | apic= [APIC,X86-32] Advanced Programmable Interrupt Controller |
c8facbb6 | 348 | Change the output verbosity whilst booting |
1da177e4 LT |
349 | Format: { quiet (default) | verbose | debug } |
350 | Change the amount of debugging information output | |
351 | when initialising the APIC and IO-APIC components. | |
a9913044 | 352 | |
b0f83b28 BH |
353 | autoconf= [IPV6] |
354 | See Documentation/networking/ipv6.txt. | |
355 | ||
9636bc05 CG |
356 | show_lapic= [APIC,X86] Advanced Programmable Interrupt Controller |
357 | Limit apic dumping. The parameter defines the maximal | |
358 | number of local apics being dumped. Also it is possible | |
359 | to set it to "all" by meaning -- no limit here. | |
360 | Format: { 1 (default) | 2 | ... | all }. | |
361 | The parameter valid if only apic=debug or | |
362 | apic=verbose is specified. | |
363 | Example: apic=debug show_lapic=all | |
364 | ||
1da177e4 | 365 | apm= [APM] Advanced Power Management |
71f77055 | 366 | See header of arch/x86/kernel/apm_32.c. |
1da177e4 | 367 | |
1da177e4 LT |
368 | arcrimi= [HW,NET] ARCnet - "RIM I" (entirely mem-mapped) cards |
369 | Format: <io>,<irq>,<nodeID> | |
370 | ||
371 | ataflop= [HW,M68k] | |
372 | ||
373 | atarimouse= [HW,MOUSE] Atari Mouse | |
374 | ||
375 | atascsi= [HW,SCSI] Atari SCSI | |
376 | ||
377 | atkbd.extra= [HW] Enable extra LEDs and keys on IBM RapidAccess, | |
378 | EzKey and similar keyboards | |
379 | ||
380 | atkbd.reset= [HW] Reset keyboard during initialization | |
381 | ||
a9913044 RD |
382 | atkbd.set= [HW] Select keyboard code set |
383 | Format: <int> (2 = AT (default), 3 = PS/2) | |
1da177e4 LT |
384 | |
385 | atkbd.scroll= [HW] Enable scroll wheel on MS Office and similar | |
386 | keyboards | |
387 | ||
388 | atkbd.softraw= [HW] Choose between synthetic and real raw mode | |
389 | Format: <bool> (0 = real, 1 = synthetic (default)) | |
a9913044 RD |
390 | |
391 | atkbd.softrepeat= [HW] | |
392 | Use software keyboard repeat | |
1da177e4 LT |
393 | |
394 | autotest [IA64] | |
395 | ||
1da177e4 LT |
396 | baycom_epp= [HW,AX25] |
397 | Format: <io>,<mode> | |
a9913044 | 398 | |
1da177e4 LT |
399 | baycom_par= [HW,AX25] BayCom Parallel Port AX.25 Modem |
400 | Format: <io>,<mode> | |
401 | See header of drivers/net/hamradio/baycom_par.c. | |
402 | ||
a9913044 RD |
403 | baycom_ser_fdx= [HW,AX25] |
404 | BayCom Serial Port AX.25 Modem (Full Duplex Mode) | |
1da177e4 LT |
405 | Format: <io>,<irq>,<mode>[,<baud>] |
406 | See header of drivers/net/hamradio/baycom_ser_fdx.c. | |
407 | ||
a9913044 RD |
408 | baycom_ser_hdx= [HW,AX25] |
409 | BayCom Serial Port AX.25 Modem (Half Duplex Mode) | |
1da177e4 LT |
410 | Format: <io>,<irq>,<mode> |
411 | See header of drivers/net/hamradio/baycom_ser_hdx.c. | |
412 | ||
bfe8df3d RD |
413 | boot_delay= Milliseconds to delay each printk during boot. |
414 | Values larger than 10 seconds (10000) are changed to | |
415 | no delay (0). | |
416 | Format: integer | |
417 | ||
35fc908d AH |
418 | bootmem_debug [KNL] Enable bootmem allocator debug messages. |
419 | ||
1da177e4 | 420 | bttv.card= [HW,V4L] bttv (bt848 + bt878 based grabber cards) |
a9913044 RD |
421 | bttv.radio= Most important insmod options are available as |
422 | kernel args too. | |
1da177e4 LT |
423 | bttv.pll= See Documentation/video4linux/bttv/Insmod-options |
424 | bttv.tuner= and Documentation/video4linux/bttv/CARDLIST | |
425 | ||
426 | BusLogic= [HW,SCSI] | |
427 | See drivers/scsi/BusLogic.c, comment before function | |
428 | BusLogic_ParseDriverOptions(). | |
429 | ||
430 | c101= [NET] Moxa C101 synchronous serial card | |
431 | ||
cd4f0ef7 | 432 | cachesize= [BUGS=X86-32] Override level 2 CPU cache size detection. |
1da177e4 LT |
433 | Sometimes CPU hardware bugs make them report the cache |
434 | size incorrectly. The kernel will attempt work arounds | |
435 | to fix known problems, but for some CPUs it is not | |
436 | possible to determine what the correct size should be. | |
437 | This option provides an override for these situations. | |
438 | ||
20510f2f JM |
439 | capability.disable= |
440 | [SECURITY] Disable capabilities. This would normally | |
441 | be used only if an alternative security model is to be | |
442 | configured. Potentially dangerous and should only be | |
443 | used if you are entirely sure of the consequences. | |
444 | ||
14ff56bb SO |
445 | ccw_timeout_log [S390] |
446 | See Documentation/s390/CommonIO for details. | |
1da177e4 | 447 | |
8bab8dde PM |
448 | cgroup_disable= [KNL] Disable a particular controller |
449 | Format: {name of the controller(s) to disable} | |
450 | {Currently supported controllers - "memory"} | |
451 | ||
1da177e4 LT |
452 | checkreqprot [SELINUX] Set initial checkreqprot flag value. |
453 | Format: { "0" | "1" } | |
454 | See security/selinux/Kconfig help text. | |
a9913044 RD |
455 | 0 -- check protection applied by kernel (includes |
456 | any implied execute protection). | |
1da177e4 LT |
457 | 1 -- check protection requested by application. |
458 | Default value is set via a kernel config option. | |
a9913044 RD |
459 | Value can be changed at runtime via |
460 | /selinux/checkreqprot. | |
461 | ||
661ca0da SO |
462 | cio_ignore= [S390] |
463 | See Documentation/s390/CommonIO for details. | |
464 | ||
cd4f0ef7 | 465 | clock= [BUGS=X86-32, HW] gettimeofday clocksource override. |
734efb46 | 466 | [Deprecated] |
3f6dee9b | 467 | Forces specified clocksource (if available) to be used |
734efb46 | 468 | when calculating gettimeofday(). If specified |
3f6dee9b | 469 | clocksource is not available, it defaults to PIT. |
1da177e4 LT |
470 | Format: { pit | tsc | cyclone | pmtmr } |
471 | ||
3d6ac984 RD |
472 | clocksource= [GENERIC_TIME] Override the default clocksource |
473 | Format: <string> | |
474 | Override the default clocksource and use the clocksource | |
475 | with the name specified. | |
476 | Some clocksource names to choose from, depending on | |
477 | the platform: | |
478 | [all] jiffies (this is the base, fallback clocksource) | |
479 | [ACPI] acpi_pm | |
480 | [ARM] imx_timer1,OSTS,netx_timer,mpu_timer2, | |
481 | pxa_timer,timer3,32k_counter,timer0_1 | |
482 | [AVR32] avr32 | |
cd4f0ef7 | 483 | [X86-32] pit,hpet,tsc,vmi-timer; |
3d6ac984 RD |
484 | scx200_hrt on Geode; cyclone on IBM x440 |
485 | [MIPS] MIPS | |
486 | [PARISC] cr16 | |
487 | [S390] tod | |
488 | [SH] SuperH | |
489 | [SPARC64] tick | |
490 | [X86-64] hpet,tsc | |
491 | ||
ac72e788 AK |
492 | clearcpuid=BITNUM [X86] |
493 | Disable CPUID feature X for the kernel. See | |
07983f0e RD |
494 | arch/x86/include/asm/cpufeature.h for the valid bit |
495 | numbers. Note the Linux specific bits are not necessarily | |
ac72e788 AK |
496 | stable over kernel options, but the vendor specific |
497 | ones should be. | |
498 | Also note that user programs calling CPUID directly | |
499 | or using the feature without checking anything | |
500 | will still see it. This just prevents it from | |
501 | being used by the kernel or shown in /proc/cpuinfo. | |
502 | Also note the kernel might malfunction if you disable | |
503 | some critical bits. | |
504 | ||
14f966e7 RJ |
505 | cmo_free_hint= [PPC] Format: { yes | no } |
506 | Specify whether pages are marked as being inactive | |
507 | when they are freed. This is used in CMO environments | |
508 | to determine OS memory pressure for page stealing by | |
509 | a hypervisor. | |
510 | Default: yes | |
511 | ||
6cececfc | 512 | code_bytes [X86] How many bytes of object code to print |
a25bd949 | 513 | in an oops report. |
86c41837 CE |
514 | Range: 0 - 8192 |
515 | Default: 64 | |
516 | ||
1da177e4 | 517 | com20020= [HW,NET] ARCnet - COM20020 chipset |
a9913044 RD |
518 | Format: |
519 | <io>[,<irq>[,<nodeID>[,<backplane>[,<ckp>[,<timeout>]]]]] | |
1da177e4 LT |
520 | |
521 | com90io= [HW,NET] ARCnet - COM90xx chipset (IO-mapped buffers) | |
522 | Format: <io>[,<irq>] | |
523 | ||
a9913044 RD |
524 | com90xx= [HW,NET] |
525 | ARCnet - COM90xx chipset (memory-mapped buffers) | |
1da177e4 LT |
526 | Format: <io>[,<irq>[,<memstart>]] |
527 | ||
528 | condev= [HW,S390] console device | |
529 | conmode= | |
a9913044 | 530 | |
1da177e4 LT |
531 | console= [KNL] Output console device and options. |
532 | ||
533 | tty<n> Use the virtual console device <n>. | |
534 | ||
535 | ttyS<n>[,options] | |
f1a1c2dc | 536 | ttyUSB0[,options] |
1da177e4 | 537 | Use the specified serial port. The options are of |
f1a1c2dc RD |
538 | the form "bbbbpnf", where "bbbb" is the baud rate, |
539 | "p" is parity ("n", "o", or "e"), "n" is number of | |
540 | bits, and "f" is flow control ("r" for RTS or | |
541 | omit it). Default is "9600n8". | |
542 | ||
543 | See Documentation/serial-console.txt for more | |
544 | information. See | |
545 | Documentation/networking/netconsole.txt for an | |
546 | alternative. | |
1da177e4 | 547 | |
18a8bd94 YL |
548 | uart[8250],io,<addr>[,options] |
549 | uart[8250],mmio,<addr>[,options] | |
1da177e4 LT |
550 | Start an early, polled-mode console on the 8250/16550 |
551 | UART at the specified I/O port or MMIO address, | |
552 | switching to the matching ttyS device later. The | |
553 | options are the same as for ttyS, above. | |
554 | ||
f7511d5f ST |
555 | If the device connected to the port is not a TTY but a braille |
556 | device, prepend "brl," before the device type, for instance | |
557 | console=brl,ttyS0 | |
558 | For now, only VisioBraille is supported. | |
559 | ||
f324edc8 DM |
560 | consoleblank= [KNL] The console blank (screen saver) timeout in |
561 | seconds. Defaults to 10*60 = 10mins. A value of 0 | |
562 | disables the blank timer. | |
563 | ||
4cb0e11b HK |
564 | coredump_filter= |
565 | [KNL] Change the default value for | |
566 | /proc/<pid>/coredump_filter. | |
567 | See also Documentation/filesystems/proc.txt. | |
568 | ||
1da177e4 | 569 | cpcihp_generic= [HW,PCI] Generic port I/O CompactPCI driver |
a9913044 RD |
570 | Format: |
571 | <first_slot>,<last_slot>,<port>,<enum_bit>[,<debug>] | |
1da177e4 | 572 | |
dc009d92 EB |
573 | crashkernel=nn[KMG]@ss[KMG] |
574 | [KNL] Reserve a chunk of physical memory to | |
575 | hold a kernel to switch to with kexec on panic. | |
576 | ||
fb391599 BW |
577 | crashkernel=range1:size1[,range2:size2,...][@offset] |
578 | [KNL] Same as above, but depends on the memory | |
579 | in the running system. The syntax of range is | |
580 | start-[end] where start and end are both | |
581 | a memory unit (amount[KMG]). See also | |
582 | Documentation/kdump/kdump.txt for a example. | |
583 | ||
1da177e4 LT |
584 | cs89x0_dma= [HW,NET] |
585 | Format: <dma> | |
586 | ||
587 | cs89x0_media= [HW,NET] | |
588 | Format: { rj45 | aui | bnc } | |
a9913044 | 589 | |
a9913044 | 590 | dasd= [HW,NET] |
1da177e4 LT |
591 | See header of drivers/s390/block/dasd_devmap.c. |
592 | ||
593 | db9.dev[2|3]= [HW,JOY] Multisystem joystick support via parallel port | |
594 | (one device per port) | |
595 | Format: <port#>,<type> | |
596 | See also Documentation/input/joystick-parport.txt | |
597 | ||
598 | debug [KNL] Enable kernel debugging (events log level). | |
599 | ||
cae2ed9a IM |
600 | debug_locks_verbose= |
601 | [KNL] verbose self-tests | |
602 | Format=<0|1> | |
603 | Print debugging info while doing the locking API | |
604 | self-tests. | |
605 | We default to 0 (no extra messages), setting it to | |
606 | 1 will print _a lot_ more information - normally | |
607 | only useful to kernel developers. | |
608 | ||
3ac7fe5a TG |
609 | debug_objects [KNL] Enable object debugging |
610 | ||
3e8ebb5c KM |
611 | no_debug_objects |
612 | [KNL] Disable object debugging | |
613 | ||
d3af01f1 TG |
614 | debugpat [X86] Enable PAT debugging |
615 | ||
2d27a966 | 616 | decnet.addr= [HW,NET] |
1da177e4 LT |
617 | Format: <area>[,<node>] |
618 | See also Documentation/networking/decnet.txt. | |
619 | ||
0cb55ad2 RD |
620 | default_hugepagesz= |
621 | [same as hugepagesz=] The size of the default | |
622 | HugeTLB page size. This is the size represented by | |
623 | the legacy /proc/ hugepages APIs, used for SHM, and | |
624 | default size when mounting hugetlbfs filesystems. | |
625 | Defaults to the default architecture's huge page size | |
626 | if not specified. | |
55ff9780 | 627 | |
1da177e4 LT |
628 | dhash_entries= [KNL] |
629 | Set number of hash buckets for dentry cache. | |
a9913044 | 630 | |
1da177e4 LT |
631 | digi= [HW,SERIAL] |
632 | IO parameters + enable/disable command. | |
633 | ||
634 | digiepca= [HW,SERIAL] | |
635 | See drivers/char/README.epca and | |
31c00fc1 | 636 | Documentation/serial/digiepca.txt. |
1da177e4 | 637 | |
b0f83b28 BH |
638 | disable= [IPV6] |
639 | See Documentation/networking/ipv6.txt. | |
640 | ||
641 | disable_ipv6= [IPV6] | |
642 | See Documentation/networking/ipv6.txt. | |
643 | ||
95ffa243 | 644 | disable_mtrr_cleanup [X86] |
95ffa243 YL |
645 | The kernel tries to adjust MTRR layout from continuous |
646 | to discrete, to make X server driver able to add WB | |
0cb55ad2 | 647 | entry later. This parameter disables that. |
95ffa243 | 648 | |
093af8d7 | 649 | disable_mtrr_trim [X86, Intel and AMD only] |
99fc8d42 JB |
650 | By default the kernel will trim any uncacheable |
651 | memory out of your available memory pool based on | |
652 | MTRR settings. This parameter disables that behavior, | |
653 | possibly causing your machine to run very slowly. | |
654 | ||
6cececfc | 655 | disable_timer_pin_1 [X86] |
0cb55ad2 RD |
656 | Disable PIN 1 of APIC timer |
657 | Can be useful to work around chipset bugs. | |
658 | ||
1da177e4 LT |
659 | dmasound= [HW,OSS] Sound subsystem buffers |
660 | ||
0cb55ad2 RD |
661 | dma_debug=off If the kernel is compiled with DMA_API_DEBUG support, |
662 | this option disables the debugging code at boot. | |
663 | ||
664 | dma_debug_entries=<number> | |
665 | This option allows to tune the number of preallocated | |
666 | entries for DMA-API debugging code. One entry is | |
667 | required per DMA-API allocation. Use this if the | |
668 | DMA-API debugging code disables itself because the | |
669 | architectural default is too low. | |
670 | ||
1745de5e JR |
671 | dma_debug_driver=<driver_name> |
672 | With this option the DMA-API debugging driver | |
673 | filter feature can be enabled at boot time. Just | |
674 | pass the driver to filter for as the parameter. | |
675 | The filter can be disabled or changed to another | |
676 | driver later using sysfs. | |
677 | ||
1da177e4 LT |
678 | dscc4.setup= [NET] |
679 | ||
680 | dtc3181e= [HW,SCSI] | |
681 | ||
0cb55ad2 RD |
682 | dynamic_printk Enables pr_debug()/dev_dbg() calls if |
683 | CONFIG_DYNAMIC_PRINTK_DEBUG has been enabled. | |
684 | These can also be switched on/off via | |
685 | <debugfs>/dynamic_printk/modules | |
686 | ||
687 | earlycon= [KNL] Output early console device and options. | |
688 | uart[8250],io,<addr>[,options] | |
689 | uart[8250],mmio,<addr>[,options] | |
690 | Start an early, polled-mode console on the 8250/16550 | |
691 | UART at the specified I/O port or MMIO address. | |
692 | The options are the same as for ttyS, above. | |
693 | ||
6cececfc | 694 | earlyprintk= [X86,SH,BLACKFIN] |
1da177e4 LT |
695 | earlyprintk=vga |
696 | earlyprintk=serial[,ttySn[,baudrate]] | |
ea3acb19 | 697 | earlyprintk=ttySn[,baudrate] |
9780bc41 | 698 | earlyprintk=dbgp[debugController#] |
1da177e4 | 699 | |
a9913044 | 700 | Append ",keep" to not disable it when the real console |
1da177e4 LT |
701 | takes over. |
702 | ||
5c05917e | 703 | Only vga or serial or usb debug port at a time. |
1da177e4 LT |
704 | |
705 | Currently only ttyS0 and ttyS1 are supported. | |
706 | ||
707 | Interaction with the standard serial driver is not | |
708 | very good. | |
709 | ||
710 | The VGA output is eventually overwritten by the real | |
711 | console. | |
712 | ||
9731191f JW |
713 | ekgdboc= [X86,KGDB] Allow early kernel console debugging |
714 | ekgdboc=kbd | |
715 | ||
716 | This is desgined to be used in conjunction with | |
717 | the boot argument: earlyprintk=vga | |
718 | ||
1da177e4 LT |
719 | eata= [HW,SCSI] |
720 | ||
1da177e4 | 721 | edd= [EDD] |
8c4dd606 | 722 | Format: {"off" | "on" | "skip[mbr]"} |
1da177e4 | 723 | |
1da177e4 LT |
724 | eisa_irq_edge= [PARISC,HW] |
725 | See header of drivers/parisc/eisa.c. | |
726 | ||
cd4f0ef7 | 727 | elanfreq= [X86-32] |
1da177e4 | 728 | See comment before function elanfreq_setup() in |
71f77055 | 729 | arch/x86/kernel/cpu/cpufreq/elanfreq.c. |
1da177e4 LT |
730 | |
731 | elevator= [IOSCHED] | |
16ab3adf | 732 | Format: {"anticipatory" | "cfq" | "deadline" | "noop"} |
a9913044 RD |
733 | See Documentation/block/as-iosched.txt and |
734 | Documentation/block/deadline-iosched.txt for details. | |
735 | ||
6cececfc | 736 | elfcorehdr= [IA64,PPC,SH,X86] |
a9913044 | 737 | Specifies physical address of start of kernel core |
aac04b32 VG |
738 | image elf header. Generally kexec loader will |
739 | pass this option to capture kernel. | |
740 | See Documentation/kdump/kdump.txt for details. | |
1da177e4 | 741 | |
0cb55ad2 RD |
742 | enable_mtrr_cleanup [X86] |
743 | The kernel tries to adjust MTRR layout from continuous | |
744 | to discrete, to make X server driver able to add WB | |
745 | entry later. This parameter enables that. | |
746 | ||
ca1eda2d | 747 | enable_timer_pin_1 [X86] |
0cb55ad2 RD |
748 | Enable PIN 1 of APIC timer |
749 | Can be useful to work around chipset bugs | |
750 | (in particular on some ATI chipsets). | |
751 | The kernel tries to set a reasonable default. | |
752 | ||
1da177e4 LT |
753 | enforcing [SELINUX] Set initial enforcing status. |
754 | Format: {"0" | "1"} | |
755 | See security/selinux/Kconfig help text. | |
756 | 0 -- permissive (log only, no denials). | |
757 | 1 -- enforcing (deny and log). | |
758 | Default value is 0. | |
759 | Value can be changed at runtime via /selinux/enforce. | |
760 | ||
a08f82d0 HY |
761 | erst_disable [ACPI] |
762 | Disable Error Record Serialization Table (ERST) | |
763 | support. | |
764 | ||
1da177e4 LT |
765 | ether= [HW,NET] Ethernet cards parameters |
766 | This option is obsoleted by the "netdev=" option, which | |
767 | has equivalent usage. See its documentation for details. | |
768 | ||
de1ba09b AM |
769 | failslab= |
770 | fail_page_alloc= | |
771 | fail_make_request=[KNL] | |
772 | General fault injection mechanism. | |
773 | Format: <interval>,<probability>,<space>,<times> | |
774 | See also /Documentation/fault-injection/. | |
775 | ||
1da177e4 LT |
776 | fd_mcs= [HW,SCSI] |
777 | See header of drivers/scsi/fd_mcs.c. | |
778 | ||
779 | fdomain= [HW,SCSI] | |
780 | See header of drivers/scsi/fdomain.c. | |
781 | ||
782 | floppy= [HW] | |
31c00fc1 | 783 | See Documentation/blockdev/floppy.txt. |
1da177e4 | 784 | |
f13ae30e AC |
785 | force_pal_cache_flush |
786 | [IA-64] Avoid check_sal_cache_flush which may hang on | |
787 | buggy SAL_CACHE_FLUSH implementations. Using this | |
788 | parameter will force ia64_sal_cache_flush to call | |
789 | ia64_pal_cache_flush instead of SAL_CACHE_FLUSH. | |
790 | ||
d9e54076 | 791 | ftrace=[tracer] |
2af15d6a | 792 | [FTRACE] will set and start the specified tracer |
d9e54076 PZ |
793 | as early as possible in order to facilitate early |
794 | boot debugging. | |
795 | ||
cecbca96 | 796 | ftrace_dump_on_oops[=orig_cpu] |
2af15d6a | 797 | [FTRACE] will dump the trace buffers on oops. |
cecbca96 FW |
798 | If no parameter is passed, ftrace will dump |
799 | buffers of all CPUs, but if you pass orig_cpu, it will | |
800 | dump only the buffer of the CPU that triggered the | |
801 | oops. | |
2af15d6a SR |
802 | |
803 | ftrace_filter=[function-list] | |
804 | [FTRACE] Limit the functions traced by the function | |
805 | tracer at boot up. function-list is a comma separated | |
806 | list of functions. This list can be changed at run | |
807 | time by the set_ftrace_filter file in the debugfs | |
808 | tracing directory. | |
809 | ||
810 | ftrace_notrace=[function-list] | |
811 | [FTRACE] Do not trace the functions specified in | |
812 | function-list. This list can be changed at run time | |
813 | by the set_ftrace_notrace file in the debugfs | |
814 | tracing directory. | |
d9e54076 | 815 | |
369bc18f SA |
816 | ftrace_graph_filter=[function-list] |
817 | [FTRACE] Limit the top level callers functions traced | |
818 | by the function graph tracer at boot up. | |
819 | function-list is a comma separated list of functions | |
820 | that can be changed at run time by the | |
821 | set_graph_function file in the debugfs tracing directory. | |
822 | ||
1da177e4 LT |
823 | gamecon.map[2|3]= |
824 | [HW,JOY] Multisystem joystick and NES/SNES/PSX pad | |
825 | support via parallel port (up to 5 devices per port) | |
826 | Format: <port#>,<pad1>,<pad2>,<pad3>,<pad4>,<pad5> | |
827 | See also Documentation/input/joystick-parport.txt | |
828 | ||
829 | gamma= [HW,DRM] | |
830 | ||
aaf23042 YL |
831 | gart_fix_e820= [X86_64] disable the fix e820 for K8 GART |
832 | Format: off | on | |
833 | default: on | |
834 | ||
2521f2c2 PO |
835 | gcov_persist= [GCOV] When non-zero (default), profiling data for |
836 | kernel modules is saved and remains accessible via | |
837 | debugfs, even when the module is unloaded/reloaded. | |
838 | When zero, profiling data is discarded and associated | |
839 | debugfs files are removed at module unload time. | |
840 | ||
1da177e4 LT |
841 | gdth= [HW,SCSI] |
842 | See header of drivers/scsi/gdth.c. | |
843 | ||
844 | gpt [EFI] Forces disk with valid GPT signature but | |
845 | invalid Protective MBR to be treated as GPT. | |
846 | ||
1da177e4 LT |
847 | gvp11= [HW,SCSI] |
848 | ||
849 | hashdist= [KNL,NUMA] Large hashes allocated during boot | |
850 | are distributed across NUMA nodes. Defaults on | |
429aa0fc | 851 | for 64bit NUMA, off otherwise. |
a9913044 | 852 | Format: 0 | 1 (for off | on) |
1da177e4 LT |
853 | |
854 | hcl= [IA-64] SGI's Hardware Graph compatibility layer | |
855 | ||
856 | hd= [EIDE] (E)IDE hard drive subsystem geometry | |
857 | Format: <cyl>,<head>,<sect> | |
858 | ||
ea8c071c HY |
859 | hest_disable [ACPI] |
860 | Disable Hardware Error Source Table (HEST) support; | |
861 | corresponding firmware-first mode error processing | |
862 | logic will be disabled. | |
863 | ||
1da177e4 LT |
864 | highmem=nn[KMG] [KNL,BOOT] forces the highmem zone to have an exact |
865 | size of <nn>. This works even on boxes that have no | |
866 | highmem otherwise. This also works to reduce highmem | |
867 | size on bigger boxes. | |
868 | ||
54cdfdb4 TG |
869 | highres= [KNL] Enable/disable high resolution timer mode. |
870 | Valid parameters: "on", "off" | |
871 | Default: "on" | |
872 | ||
1da177e4 LT |
873 | hisax= [HW,ISDN] |
874 | See Documentation/isdn/README.HiSax. | |
875 | ||
0cb55ad2 RD |
876 | hlt [BUGS=ARM,SH] |
877 | ||
878 | hpet= [X86-32,HPET] option to control HPET usage | |
879 | Format: { enable (default) | disable | force | | |
880 | verbose } | |
881 | disable: disable HPET and use PIT instead | |
882 | force: allow force enabled of undocumented chips (ICH4, | |
883 | VIA, nVidia) | |
884 | verbose: show contents of HPET registers during setup | |
885 | ||
b4718e62 AK |
886 | hugepages= [HW,X86-32,IA-64] HugeTLB pages to allocate at boot. |
887 | hugepagesz= [HW,IA-64,PPC,X86-64] The size of the HugeTLB pages. | |
0d9ea754 JT |
888 | On x86-64 and powerpc, this option can be specified |
889 | multiple times interleaved with hugepages= to reserve | |
890 | huge pages of different sizes. Valid pages sizes on | |
891 | x86-64 are 2M (when the CPU supports "pse") and 1G | |
892 | (when the CPU supports the "pdpe1gb" cpuinfo flag) | |
b4718e62 AK |
893 | Note that 1GB pages can only be allocated at boot time |
894 | using hugepages= and not freed afterwards. | |
6902aa84 | 895 | |
555d61d6 HB |
896 | hvc_iucv= [S390] Number of z/VM IUCV hypervisor console (HVC) |
897 | terminal devices. Valid values: 0..8 | |
431429ff HB |
898 | hvc_iucv_allow= [S390] Comma-separated list of z/VM user IDs. |
899 | If specified, z/VM IUCV HVC accepts connections | |
900 | from listed z/VM user IDs only. | |
cef7125d | 901 | |
3a853fb9 | 902 | i2c_bus= [HW] Override the default board specific I2C bus speed |
7954763b JN |
903 | or register an additional I2C bus that is not |
904 | registered from board initialization code. | |
3a853fb9 JN |
905 | Format: |
906 | <bus_id>,<clkrate> | |
907 | ||
36d95739 | 908 | i8042.debug [HW] Toggle i8042 debug mode |
1da177e4 | 909 | i8042.direct [HW] Put keyboard port into non-translated mode |
84eb8d06 ML |
910 | i8042.dumbkbd [HW] Pretend that controller can only read data from |
911 | keyboard and cannot control its state | |
1da177e4 LT |
912 | (Don't attempt to blink the leds) |
913 | i8042.noaux [HW] Don't check for auxiliary (== mouse) port | |
945ef0d4 | 914 | i8042.nokbd [HW] Don't check/create keyboard port |
75d08c78 JK |
915 | i8042.noloop [HW] Disable the AUX Loopback command while probing |
916 | for the AUX port | |
1da177e4 LT |
917 | i8042.nomux [HW] Don't check presence of an active multiplexing |
918 | controller | |
919 | i8042.nopnp [HW] Don't use ACPIPnP / PnPBIOS to discover KBD/AUX | |
920 | controllers | |
921 | i8042.panicblink= | |
922 | [HW] Frequency with which keyboard LEDs should blink | |
923 | when kernel panics (default is 0.5 sec) | |
924 | i8042.reset [HW] Reset the controller during init and cleanup | |
925 | i8042.unlock [HW] Unlock (ignore) the keylock | |
926 | ||
927 | i810= [HW,DRM] | |
928 | ||
e70c9d5e DT |
929 | i8k.ignore_dmi [HW] Continue probing hardware even if DMI data |
930 | indicates that the driver is running on unsupported | |
931 | hardware. | |
1da177e4 LT |
932 | i8k.force [HW] Activate i8k driver even if SMM BIOS signature |
933 | does not match list of supported models. | |
934 | i8k.power_status | |
935 | [HW] Report power status in /proc/i8k | |
936 | (disabled by default) | |
937 | i8k.restricted [HW] Allow controlling fans only if SYS_ADMIN | |
938 | capability is set. | |
939 | ||
940 | ibmmcascsi= [HW,MCA,SCSI] IBM MicroChannel SCSI adapter | |
941 | See Documentation/mca.txt. | |
942 | ||
943 | icn= [HW,ISDN] | |
944 | Format: <io>[,<membase>[,<icn_id>[,<icn_id2>]]] | |
945 | ||
0af80c04 DF |
946 | ide-core.nodma= [HW] (E)IDE subsystem |
947 | Format: =0.0 to prevent dma on hda, =0.1 hdb =1.0 hdc | |
075affcb BZ |
948 | .vlb_clock .pci_clock .noflush .nohpa .noprobe .nowerr |
949 | .cdrom .chs .ignore_cable are additional options | |
1c10e938 | 950 | See Documentation/ide/ide.txt. |
1da177e4 | 951 | |
0cb55ad2 RD |
952 | ide-pci-generic.all-generic-ide [HW] (E)IDE subsystem |
953 | Claim all unknown PCI IDE storage controllers. | |
954 | ||
f039b754 | 955 | idle= [X86] |
ada9cfdd RD |
956 | Format: idle=poll, idle=mwait, idle=halt, idle=nomwait |
957 | Poll forces a polling idle loop that can slightly | |
958 | improve the performance of waking up a idle CPU, but | |
959 | will use a lot of power and make the system run hot. | |
960 | Not recommended. | |
961 | idle=mwait: On systems which support MONITOR/MWAIT but | |
962 | the kernel chose to not use it because it doesn't save | |
963 | as much power as a normal idle loop, use the | |
964 | MONITOR/MWAIT idle loop anyways. Performance should be | |
965 | the same as idle=poll. | |
966 | idle=halt: Halt is forced to be used for CPU idle. | |
c1e3b377 | 967 | In such case C2/C3 won't be used again. |
ada9cfdd | 968 | idle=nomwait: Disable mwait for CPU C-states |
a9913044 | 969 | |
79290822 IM |
970 | ignore_loglevel [KNL] |
971 | Ignore loglevel setting - this will print /all/ | |
972 | kernel messages to the console. Useful for debugging. | |
973 | ||
1da177e4 LT |
974 | ihash_entries= [KNL] |
975 | Set number of hash buckets for inode cache. | |
976 | ||
3323eec9 MZ |
977 | ima_audit= [IMA] |
978 | Format: { "0" | "1" } | |
979 | 0 -- integrity auditing messages. (Default) | |
980 | 1 -- enable informational integrity auditing messages. | |
981 | ||
982 | ima_hash= [IMA] | |
a9ed83a5 | 983 | Format: { "sha1" | "md5" } |
3323eec9 MZ |
984 | default: "sha1" |
985 | ||
5789ba3b EP |
986 | ima_tcb [IMA] |
987 | Load a policy which meets the needs of the Trusted | |
988 | Computing Base. This means IMA will measure all | |
989 | programs exec'd, files mmap'd for exec, and all files | |
990 | opened for read by uid=0. | |
991 | ||
1da177e4 LT |
992 | in2000= [HW,SCSI] |
993 | See header of drivers/scsi/in2000.c. | |
994 | ||
995 | init= [KNL] | |
996 | Format: <full_path> | |
997 | Run specified binary instead of /sbin/init as init | |
998 | process. | |
999 | ||
1000 | initcall_debug [KNL] Trace initcalls as they are executed. Useful | |
1001 | for working out where the kernel is dying during | |
1002 | startup. | |
1003 | ||
1004 | initrd= [BOOT] Specify the location of the initial ramdisk | |
1005 | ||
1006 | inport.irq= [HW] Inport (ATI XL and Microsoft) busmouse driver | |
1007 | Format: <irq> | |
1008 | ||
ba395927 | 1009 | intel_iommu= [DMAR] Intel IOMMU driver (DMAR) option |
0cd5c3c8 KM |
1010 | on |
1011 | Enable intel iommu driver. | |
ba395927 KA |
1012 | off |
1013 | Disable intel iommu driver. | |
1014 | igfx_off [Default Off] | |
1015 | By default, gfx is mapped as normal device. If a gfx | |
1016 | device has a dedicated DMAR unit, the DMAR unit is | |
1017 | bypassed by not enabling DMAR with this option. In | |
1018 | this case, gfx device will use physical address for | |
1019 | DMA. | |
7d3b03ce KA |
1020 | forcedac [x86_64] |
1021 | With this option iommu will not optimize to look | |
1022 | for io virtual address below 32 bit forcing dual | |
1023 | address cycle on pci bus for cards supporting greater | |
1024 | than 32 bit addressing. The default is to look | |
1025 | for translation below 32 bit and if not available | |
1026 | then look in the higher range. | |
5e0d2a6f | 1027 | strict [Default Off] |
1028 | With this option on every unmap_single operation will | |
1029 | result in a hardware IOTLB flush operation as opposed | |
1030 | to batching them for performance. | |
ba395927 | 1031 | |
0cb55ad2 RD |
1032 | inttest= [IA64] |
1033 | ||
1034 | iomem= Disable strict checking of access to MMIO memory | |
1035 | strict regions from userspace. | |
1036 | relaxed | |
1037 | ||
1038 | iommu= [x86] | |
1039 | off | |
1040 | force | |
1041 | noforce | |
1042 | biomerge | |
1043 | panic | |
1044 | nopanic | |
1045 | merge | |
1046 | nomerge | |
1047 | forcesac | |
1048 | soft | |
4ed0d3e6 | 1049 | pt [x86, IA64] |
0cb55ad2 RD |
1050 | |
1051 | io7= [HW] IO7 for Marvel based alpha systems | |
1052 | See comment before marvel_specify_io7 in | |
1053 | arch/alpha/kernel/core_marvel.c. | |
1054 | ||
6cececfc | 1055 | io_delay= [X86] I/O delay method |
6e7c4025 IM |
1056 | 0x80 |
1057 | Standard port 0x80 based delay | |
1058 | 0xed | |
1059 | Alternate port 0xed based delay (needed on some systems) | |
b02aae9c | 1060 | udelay |
6e7c4025 IM |
1061 | Simple two microseconds delay |
1062 | none | |
1063 | No delay | |
b02aae9c | 1064 | |
1da177e4 | 1065 | ip= [IP_PNP] |
dc7a0816 | 1066 | See Documentation/filesystems/nfs/nfsroot.txt. |
1da177e4 LT |
1067 | |
1068 | ip2= [HW] Set IO/IRQ pairs for up to 4 IntelliPort boards | |
c8facbb6 RD |
1069 | See comment before ip2_setup() in |
1070 | drivers/char/ip2/ip2base.c. | |
1da177e4 LT |
1071 | |
1072 | ips= [HW,SCSI] Adaptec / IBM ServeRAID controller | |
1073 | See header of drivers/scsi/ips.c. | |
1074 | ||
200803df AC |
1075 | irqfixup [HW] |
1076 | When an interrupt is not handled search all handlers | |
1077 | for it. Intended to get systems with badly broken | |
1078 | firmware running. | |
1079 | ||
1080 | irqpoll [HW] | |
1081 | When an interrupt is not handled search all handlers | |
1082 | for it. Also check all handlers each timer | |
1083 | interrupt. Intended to get systems with badly broken | |
1084 | firmware running. | |
1085 | ||
1da177e4 | 1086 | isapnp= [ISAPNP] |
a9913044 | 1087 | Format: <RDP>,<reset>,<pci_scan>,<verbosity> |
1da177e4 LT |
1088 | |
1089 | isolcpus= [KNL,SMP] Isolate CPUs from the general scheduler. | |
22f2e280 DF |
1090 | Format: |
1091 | <cpu number>,...,<cpu number> | |
1092 | or | |
b225d44e LZ |
1093 | <cpu number>-<cpu number> |
1094 | (must be a positive range in ascending order) | |
22f2e280 DF |
1095 | or a mixture |
1096 | <cpu number>,...,<cpu number>-<cpu number> | |
b225d44e | 1097 | |
1da177e4 LT |
1098 | This option can be used to specify one or more CPUs |
1099 | to isolate from the general SMP balancing and scheduling | |
b225d44e LZ |
1100 | algorithms. You can move a process onto or off an |
1101 | "isolated" CPU via the CPU affinity syscalls or cpuset. | |
1da177e4 LT |
1102 | <cpu number> begins at 0 and the maximum value is |
1103 | "number of CPUs in system - 1". | |
1104 | ||
1105 | This option is the preferred way to isolate CPUs. The | |
a9913044 RD |
1106 | alternative -- manually setting the CPU mask of all |
1107 | tasks in the system -- can cause problems and | |
1108 | suboptimal load balancer performance. | |
1da177e4 | 1109 | |
a9913044 | 1110 | iucv= [HW,NET] |
1da177e4 LT |
1111 | |
1112 | js= [HW,JOY] Analog joystick | |
1113 | See Documentation/input/joystick.txt. | |
1114 | ||
0cb55ad2 RD |
1115 | keepinitrd [HW,ARM] |
1116 | ||
6cececfc | 1117 | kernelcore=nn[KMG] [KNL,X86,IA-64,PPC] This parameter |
ed7ed365 MG |
1118 | specifies the amount of memory usable by the kernel |
1119 | for non-movable allocations. The requested amount is | |
1120 | spread evenly throughout all nodes in the system. The | |
1121 | remaining memory in each node is used for Movable | |
1122 | pages. In the event, a node is too small to have both | |
1123 | kernelcore and Movable pages, kernelcore pages will | |
1124 | take priority and other nodes will have a larger number | |
1125 | of kernelcore pages. The Movable zone is used for the | |
1126 | allocation of pages that may be reclaimed or moved | |
1127 | by the page migration subsystem. This means that | |
1128 | HugeTLB pages may not be allocated from this zone. | |
1129 | Note that allocations like PTEs-from-HighMem still | |
1130 | use the HighMem zone if it exists, and the Normal | |
1131 | zone if it does not. | |
1132 | ||
4fe1da4e JW |
1133 | kgdbdbgp= [KGDB,HW] kgdb over EHCI usb debug port. |
1134 | Format: <Controller#>[,poll interval] | |
1135 | The controller # is the number of the ehci usb debug | |
1136 | port as it is probed via PCI. The poll interval is | |
1137 | optional and is the number seconds in between | |
1138 | each poll cycle to the debug port in case you need | |
1139 | the functionality for interrupting the kernel with | |
1140 | gdb or control-c on the dbgp connection. When | |
1141 | not using this parameter you use sysrq-g to break into | |
1142 | the kernel debugger. | |
1143 | ||
84c08fd6 | 1144 | kgdboc= [KGDB,HW] kgdb over consoles. |
ada64e4c JW |
1145 | Requires a tty driver that supports console polling, |
1146 | or a supported polling keyboard driver (non-usb). | |
1147 | Serial only format: <serial_device>[,baud] | |
1148 | keyboard only format: kbd | |
1149 | keyboard and serial format: kbd,<serial_device>[,baud] | |
6cdf6e06 | 1150 | |
84c08fd6 JW |
1151 | kgdbwait [KGDB] Stop kernel execution and enter the |
1152 | kernel debugger at the earliest opportunity. | |
1153 | ||
9bed90c6 FF |
1154 | kmac= [MIPS] korina ethernet MAC address. |
1155 | Configure the RouterBoard 532 series on-chip | |
1156 | Ethernet adapter MAC address. | |
1157 | ||
04f70336 CM |
1158 | kmemleak= [KNL] Boot-time kmemleak enable/disable |
1159 | Valid arguments: on, off | |
1160 | Default: on | |
1161 | ||
6cececfc | 1162 | kstack=N [X86] Print N words from the kernel stack |
0cb55ad2 RD |
1163 | in oops dumps. |
1164 | ||
fef07aae AP |
1165 | kvm.ignore_msrs=[KVM] Ignore guest accesses to unhandled MSRs. |
1166 | Default is 0 (don't ignore, but inject #GP) | |
1167 | ||
1168 | kvm.oos_shadow= [KVM] Disable out-of-sync shadow paging. | |
1169 | Default is 1 (enabled) | |
1170 | ||
1171 | kvm-amd.nested= [KVM,AMD] Allow nested virtualization in KVM/SVM. | |
1172 | Default is 0 (off) | |
1173 | ||
1174 | kvm-amd.npt= [KVM,AMD] Disable nested paging (virtualized MMU) | |
1175 | for all guests. | |
1176 | Default is 1 (enabled) if in 64bit or 32bit-PAE mode | |
1177 | ||
1178 | kvm-intel.bypass_guest_pf= | |
1179 | [KVM,Intel] Disables bypassing of guest page faults | |
1180 | on Intel chips. Default is 1 (enabled) | |
1181 | ||
1182 | kvm-intel.ept= [KVM,Intel] Disable extended page tables | |
1183 | (virtualized MMU) support on capable Intel chips. | |
1184 | Default is 1 (enabled) | |
1185 | ||
1186 | kvm-intel.emulate_invalid_guest_state= | |
1187 | [KVM,Intel] Enable emulation of invalid guest states | |
1188 | Default is 0 (disabled) | |
1189 | ||
1190 | kvm-intel.flexpriority= | |
1191 | [KVM,Intel] Disable FlexPriority feature (TPR shadow). | |
1192 | Default is 1 (enabled) | |
1193 | ||
1194 | kvm-intel.unrestricted_guest= | |
1195 | [KVM,Intel] Disable unrestricted guest feature | |
1196 | (virtualized real and unpaged mode) on capable | |
1197 | Intel chips. Default is 1 (enabled) | |
1198 | ||
1199 | kvm-intel.vpid= [KVM,Intel] Disable Virtual Processor Identification | |
1200 | feature (tagged TLBs) on capable Intel chips. | |
1201 | Default is 1 (enabled) | |
1202 | ||
1da177e4 LT |
1203 | l2cr= [PPC] |
1204 | ||
a78bfbfc RB |
1205 | l3cr= [PPC] |
1206 | ||
cd4f0ef7 | 1207 | lapic [X86-32,APIC] Enable the local APIC even if BIOS |
a9913044 | 1208 | disabled it. |
1da177e4 | 1209 | |
6cececfc | 1210 | lapic_timer_c2_ok [X86,APIC] trust the local apic timer |
ada9cfdd | 1211 | in C2 power state. |
e585bef8 | 1212 | |
fcb71f6f FC |
1213 | libata.dma= [LIBATA] DMA control |
1214 | libata.dma=0 Disable all PATA and SATA DMA | |
1215 | libata.dma=1 PATA and SATA Disk DMA only | |
1216 | libata.dma=2 ATAPI (CDROM) DMA only | |
1217 | libata.dma=4 Compact Flash DMA only | |
1218 | Combinations also work, so libata.dma=3 enables DMA | |
1219 | for disks and CDROMs, but not CFs. | |
20308871 MP |
1220 | |
1221 | libata.ignore_hpa= [LIBATA] Ignore HPA limit | |
1222 | libata.ignore_hpa=0 keep BIOS limits (default) | |
1223 | libata.ignore_hpa=1 ignore limits, using full disk | |
fcb71f6f | 1224 | |
78e70c23 DJ |
1225 | libata.noacpi [LIBATA] Disables use of ACPI in libata suspend/resume |
1226 | when set. | |
1227 | Format: <int> | |
1228 | ||
33267325 TH |
1229 | libata.force= [LIBATA] Force configurations. The format is comma |
1230 | separated list of "[ID:]VAL" where ID is | |
4c44f309 | 1231 | PORT[.DEVICE]. PORT and DEVICE are decimal numbers |
33267325 TH |
1232 | matching port, link or device. Basically, it matches |
1233 | the ATA ID string printed on console by libata. If | |
1234 | the whole ID part is omitted, the last PORT and DEVICE | |
1235 | values are used. If ID hasn't been specified yet, the | |
1236 | configuration applies to all ports, links and devices. | |
1237 | ||
1238 | If only DEVICE is omitted, the parameter applies to | |
1239 | the port and all links and devices behind it. DEVICE | |
1240 | number of 0 either selects the first device or the | |
1241 | first fan-out link behind PMP device. It does not | |
1242 | select the host link. DEVICE number of 15 selects the | |
1243 | host link and device attached to it. | |
1244 | ||
1245 | The VAL specifies the configuration to force. As long | |
1246 | as there's no ambiguity shortcut notation is allowed. | |
1247 | For example, both 1.5 and 1.5G would work for 1.5Gbps. | |
1248 | The following configurations can be forced. | |
1249 | ||
1250 | * Cable type: 40c, 80c, short40c, unk, ign or sata. | |
1251 | Any ID with matching PORT is used. | |
1252 | ||
1253 | * SATA link speed limit: 1.5Gbps or 3.0Gbps. | |
1254 | ||
1255 | * Transfer mode: pio[0-7], mwdma[0-4] and udma[0-7]. | |
1256 | udma[/][16,25,33,44,66,100,133] notation is also | |
1257 | allowed. | |
1258 | ||
1259 | * [no]ncq: Turn on or off NCQ. | |
1260 | ||
05944bdf TH |
1261 | * nohrst, nosrst, norst: suppress hard, soft |
1262 | and both resets. | |
1263 | ||
43c9c591 TH |
1264 | * dump_id: dump IDENTIFY data. |
1265 | ||
33267325 TH |
1266 | If there are multiple matching configurations changing |
1267 | the same attribute, the last one is used. | |
1268 | ||
7c4be253 RD |
1269 | lmb=debug [KNL] Enable lmb debug messages. |
1270 | ||
1da177e4 | 1271 | load_ramdisk= [RAM] List of ramdisks to load from floppy |
31c00fc1 | 1272 | See Documentation/blockdev/ramdisk.txt. |
1da177e4 | 1273 | |
a6b25b67 RD |
1274 | lockd.nlm_grace_period=P [NFS] Assign grace period. |
1275 | Format: <integer> | |
1da177e4 | 1276 | |
a6b25b67 RD |
1277 | lockd.nlm_tcpport=N [NFS] Assign TCP port. |
1278 | Format: <integer> | |
1279 | ||
1280 | lockd.nlm_timeout=T [NFS] Assign timeout value. | |
1281 | Format: <integer> | |
1282 | ||
1283 | lockd.nlm_udpport=M [NFS] Assign UDP port. | |
1284 | Format: <integer> | |
1da177e4 LT |
1285 | |
1286 | logibm.irq= [HW,MOUSE] Logitech Bus Mouse Driver | |
1287 | Format: <irq> | |
1288 | ||
1289 | loglevel= All Kernel Messages with a loglevel smaller than the | |
1290 | console loglevel will be printed to the console. It can | |
1291 | also be changed with klogd or other programs. The | |
1292 | loglevels are defined as follows: | |
1293 | ||
1294 | 0 (KERN_EMERG) system is unusable | |
1295 | 1 (KERN_ALERT) action must be taken immediately | |
1296 | 2 (KERN_CRIT) critical conditions | |
1297 | 3 (KERN_ERR) error conditions | |
1298 | 4 (KERN_WARNING) warning conditions | |
1299 | 5 (KERN_NOTICE) normal but significant condition | |
1300 | 6 (KERN_INFO) informational | |
1301 | 7 (KERN_DEBUG) debug-level messages | |
1302 | ||
1303 | log_buf_len=n Sets the size of the printk ring buffer, in bytes. | |
a9913044 RD |
1304 | Format: { n | nk | nM } |
1305 | n must be a power of two. The default size | |
1306 | is set in the kernel config file. | |
1da177e4 | 1307 | |
accaa24c RD |
1308 | logo.nologo [FB] Disables display of the built-in Linux logo. |
1309 | This may be used to provide more screen space for | |
1310 | kernel log messages and is useful when debugging | |
1311 | kernel boot problems. | |
1312 | ||
1da177e4 LT |
1313 | lp=0 [LP] Specify parallel ports to use, e.g, |
1314 | lp=port[,port...] lp=none,parport0 (lp0 not configured, lp1 uses | |
1315 | lp=reset first parallel port). 'lp=0' disables the | |
1316 | lp=auto printer driver. 'lp=reset' (which can be | |
1317 | specified in addition to the ports) causes | |
1318 | attached printers to be reset. Using | |
1319 | lp=port1,port2,... specifies the parallel ports | |
1320 | to associate lp devices with, starting with | |
1321 | lp0. A port specification may be 'none' to skip | |
1322 | that lp device, or a parport name such as | |
1323 | 'parport0'. Specifying 'lp=auto' instead of a | |
1324 | port specification list means that device IDs | |
1325 | from each port should be examined, to see if | |
1326 | an IEEE 1284-compliant printer is attached; if | |
1327 | so, the driver will manage that printer. | |
1328 | See also header of drivers/char/lp.c. | |
1329 | ||
1330 | lpj=n [KNL] | |
1331 | Sets loops_per_jiffy to given constant, thus avoiding | |
1332 | time-consuming boot-time autodetection (up to 250 ms per | |
1333 | CPU). 0 enables autodetection (default). To determine | |
1334 | the correct value for your kernel, boot with normal | |
1335 | autodetection and see what value is printed. Note that | |
1336 | on SMP systems the preset will be applied to all CPUs, | |
1337 | which is likely to cause problems if your CPUs need | |
1338 | significantly divergent settings. An incorrect value | |
1339 | will cause delays in the kernel to be wrong, leading to | |
1340 | unpredictable I/O errors and other breakage. Although | |
1341 | unlikely, in the extreme case this might damage your | |
1342 | hardware. | |
1343 | ||
1344 | ltpc= [NET] | |
1345 | Format: <io>,<irq>,<dma> | |
1346 | ||
a9913044 RD |
1347 | mac5380= [HW,SCSI] Format: |
1348 | <can_queue>,<cmd_per_lun>,<sg_tablesize>,<hostid>,<use_tags> | |
1da177e4 | 1349 | |
a9913044 RD |
1350 | machvec= [IA64] Force the use of a particular machine-vector |
1351 | (machvec) in a generic kernel. | |
1352 | Example: machvec=hpzx1_swiotlb | |
1da177e4 | 1353 | |
3209e70e WZ |
1354 | machtype= [Loongson] Share the same kernel image file between different |
1355 | yeeloong laptop. | |
1356 | Example: machtype=lemote-yeeloong-2f-7inch | |
1357 | ||
0cb55ad2 RD |
1358 | max_addr=nn[KMG] [KNL,BOOT,ia64] All physical memory greater |
1359 | than or equal to this physical address is ignored. | |
1da177e4 LT |
1360 | |
1361 | maxcpus= [SMP] Maximum number of processors that an SMP kernel | |
61ec7567 LB |
1362 | should make use of. maxcpus=n : n >= 0 limits the |
1363 | kernel to using 'n' processors. n=0 is a special case, | |
1364 | it is equivalent to "nosmp", which also disables | |
1365 | the IO APIC. | |
1da177e4 | 1366 | |
0cb55ad2 RD |
1367 | max_loop= [LOOP] Maximum number of loopback devices that can |
1368 | be mounted | |
1369 | Format: <1-256> | |
2b2c3750 | 1370 | |
a9913044 | 1371 | max_luns= [SCSI] Maximum number of LUNs to probe. |
1da177e4 LT |
1372 | Should be between 1 and 2^32-1. |
1373 | ||
1374 | max_report_luns= | |
a9913044 | 1375 | [SCSI] Maximum number of LUNs received. |
1da177e4 LT |
1376 | Should be between 1 and 16384. |
1377 | ||
1da177e4 LT |
1378 | mcatest= [IA-64] |
1379 | ||
cd4f0ef7 | 1380 | mce [X86-32] Machine Check Exception |
1da177e4 | 1381 | |
71cced6e | 1382 | mce=option [X86-64] See Documentation/x86/x86_64/boot-options.txt |
909dd324 | 1383 | |
1da177e4 LT |
1384 | md= [HW] RAID subsystems devices and level |
1385 | See Documentation/md.txt. | |
a9913044 | 1386 | |
1da177e4 LT |
1387 | mdacon= [MDA] |
1388 | Format: <first>,<last> | |
1389 | Specifies range of consoles to be captured by the MDA. | |
a9913044 | 1390 | |
1da177e4 LT |
1391 | mem=nn[KMG] [KNL,BOOT] Force usage of a specific amount of memory |
1392 | Amount of memory to be used when the kernel is not able | |
1393 | to see the whole system memory or for test. | |
cd4f0ef7 | 1394 | [X86-32] Use together with memmap= to avoid physical |
1da177e4 LT |
1395 | address space collisions. Without memmap= PCI devices |
1396 | could be placed at addresses belonging to unused RAM. | |
1397 | ||
cd4f0ef7 | 1398 | mem=nopentium [BUGS=X86-32] Disable usage of 4MB pages for kernel |
1da177e4 LT |
1399 | memory. |
1400 | ||
6902aa84 PM |
1401 | memchunk=nn[KMG] |
1402 | [KNL,SH] Allow user to override the default size for | |
1403 | per-device physically contiguous DMA buffers. | |
1404 | ||
6cececfc | 1405 | memmap=exactmap [KNL,X86] Enable setting of an exact |
1da177e4 LT |
1406 | E820 memory map, as specified by the user. |
1407 | Such memmap=exactmap lines can be constructed based on | |
1408 | BIOS output or other requirements. See the memmap=nn@ss | |
1409 | option description. | |
1410 | ||
1411 | memmap=nn[KMG]@ss[KMG] | |
1412 | [KNL] Force usage of a specific region of memory | |
1413 | Region of memory to be used, from ss to ss+nn. | |
1414 | ||
1415 | memmap=nn[KMG]#ss[KMG] | |
1416 | [KNL,ACPI] Mark specific memory as ACPI data. | |
1417 | Region of memory to be used, from ss to ss+nn. | |
1418 | ||
1419 | memmap=nn[KMG]$ss[KMG] | |
1420 | [KNL,ACPI] Mark specific memory as reserved. | |
1421 | Region of memory to be used, from ss to ss+nn. | |
1312848e PM |
1422 | Example: Exclude memory from 0x18690000-0x1869ffff |
1423 | memmap=64K$0x18690000 | |
1424 | or | |
1425 | memmap=0x10000$0x18690000 | |
1da177e4 | 1426 | |
9f077871 JF |
1427 | memory_corruption_check=0/1 [X86] |
1428 | Some BIOSes seem to corrupt the first 64k of | |
1429 | memory when doing things like suspend/resume. | |
1430 | Setting this option will scan the memory | |
1431 | looking for corruption. Enabling this will | |
1432 | both detect corruption and prevent the kernel | |
1433 | from using the memory being corrupted. | |
1434 | However, its intended as a diagnostic tool; if | |
1435 | repeatable BIOS-originated corruption always | |
1436 | affects the same memory, you can use memmap= | |
1437 | to prevent the kernel from using that memory. | |
1438 | ||
1439 | memory_corruption_check_size=size [X86] | |
1440 | By default it checks for corruption in the low | |
1441 | 64k, making this memory unavailable for normal | |
1442 | use. Use this parameter to scan for | |
1443 | corruption in more or less memory. | |
1444 | ||
1445 | memory_corruption_check_period=seconds [X86] | |
1446 | By default it checks for corruption every 60 | |
1447 | seconds. Use this parameter to check at some | |
1448 | other rate. 0 disables periodic checking. | |
1449 | ||
caadbdce | 1450 | memtest= [KNL,X86] Enable memtest |
c64df707 | 1451 | Format: <integer> |
c64df707 | 1452 | default : 0 <disable> |
9e5f6cf5 AH |
1453 | Specifies the number of memtest passes to be |
1454 | performed. Each pass selects another test | |
1455 | pattern from a given set of patterns. Memtest | |
1456 | fills the memory with this pattern, validates | |
1457 | memory contents and reserves bad memory | |
1458 | regions that are detected. | |
c64df707 | 1459 | |
1da177e4 LT |
1460 | meye.*= [HW] Set MotionEye Camera parameters |
1461 | See Documentation/video4linux/meye.txt. | |
1462 | ||
8f36881b AS |
1463 | mfgpt_irq= [IA-32] Specify the IRQ to use for the |
1464 | Multi-Function General Purpose Timers on AMD Geode | |
1465 | platforms. | |
1466 | ||
e6c4dc6c WT |
1467 | mfgptfix [X86-32] Fix MFGPT timers on AMD Geode platforms when |
1468 | the BIOS has incorrectly applied a workaround. TinyBIOS | |
1469 | version 0.98 is known to be affected, 0.99 fixes the | |
1470 | problem by letting the user disable the workaround. | |
1471 | ||
1da177e4 LT |
1472 | mga= [HW,DRM] |
1473 | ||
1c207f95 RD |
1474 | min_addr=nn[KMG] [KNL,BOOT,ia64] All physical memory below this |
1475 | physical address is ignored. | |
1476 | ||
39f45d7b MP |
1477 | mini2440= [ARM,HW,KNL] |
1478 | Format:[0..2][b][c][t] | |
1479 | Default: "0tb" | |
1480 | MINI2440 configuration specification: | |
1481 | 0 - The attached screen is the 3.5" TFT | |
1482 | 1 - The attached screen is the 7" TFT | |
1483 | 2 - The VGA Shield is attached (1024x768) | |
1484 | Leaving out the screen size parameter will not load | |
1485 | the TFT driver, and the framebuffer will be left | |
1486 | unconfigured. | |
1487 | b - Enable backlight. The TFT backlight pin will be | |
1488 | linked to the kernel VESA blanking code and a GPIO | |
1489 | LED. This parameter is not necessary when using the | |
1490 | VGA shield. | |
1491 | c - Enable the s3c camera interface. | |
1492 | t - Reserved for enabling touchscreen support. The | |
1493 | touchscreen support is not enabled in the mainstream | |
1494 | kernel as of 2.6.30, a preliminary port can be found | |
1495 | in the "bleeding edge" mini2440 support kernel at | |
1496 | http://repo.or.cz/w/linux-2.6/mini2440.git | |
1497 | ||
6b74ab97 MG |
1498 | mminit_loglevel= |
1499 | [KNL] When CONFIG_DEBUG_MEMORY_INIT is set, this | |
1500 | parameter allows control of the logging verbosity for | |
1501 | the additional memory initialisation checks. A value | |
1502 | of 0 disables mminit logging and a level of 4 will | |
1503 | log everything. Information is printed at KERN_DEBUG | |
1504 | so loglevel=8 may also need to be specified. | |
1505 | ||
1da177e4 LT |
1506 | mousedev.tap_time= |
1507 | [MOUSE] Maximum time between finger touching and | |
1508 | leaving touchpad surface for touch to be considered | |
1509 | a tap and be reported as a left button click (for | |
1510 | touchpads working in absolute mode only). | |
1511 | Format: <msecs> | |
1512 | mousedev.xres= [MOUSE] Horizontal screen resolution, used for devices | |
1513 | reporting absolute coordinates, such as tablets | |
1514 | mousedev.yres= [MOUSE] Vertical screen resolution, used for devices | |
1515 | reporting absolute coordinates, such as tablets | |
1516 | ||
6cececfc | 1517 | movablecore=nn[KMG] [KNL,X86,IA-64,PPC] This parameter |
0cb55ad2 RD |
1518 | is similar to kernelcore except it specifies the |
1519 | amount of memory used for migratable allocations. | |
1520 | If both kernelcore and movablecore is specified, | |
1521 | then kernelcore will be at *least* the specified | |
1522 | value but may be more. If movablecore on its own | |
1523 | is specified, the administrator must be careful | |
1524 | that the amount of memory usable for all allocations | |
1525 | is not too small. | |
1526 | ||
1da177e4 LT |
1527 | mpu401= [HW,OSS] |
1528 | Format: <io>,<irq> | |
1529 | ||
1530 | MTD_Partition= [MTD] | |
1531 | Format: <name>,<region-number>,<size>,<offset> | |
1532 | ||
a9913044 RD |
1533 | MTD_Region= [MTD] Format: |
1534 | <name>,<region-number>[,<base>,<size>,<buswidth>,<altbuswidth>] | |
1da177e4 LT |
1535 | |
1536 | mtdparts= [MTD] | |
c8facbb6 | 1537 | See drivers/mtd/cmdlinepart.c. |
1da177e4 | 1538 | |
5988af23 RH |
1539 | onenand.bdry= [HW,MTD] Flex-OneNAND Boundary Configuration |
1540 | ||
1541 | Format: [die0_boundary][,die0_lock][,die1_boundary][,die1_lock] | |
1542 | ||
1543 | boundary - index of last SLC block on Flex-OneNAND. | |
1544 | The remaining blocks are configured as MLC blocks. | |
1545 | lock - Configure if Flex-OneNAND boundary should be locked. | |
1546 | Once locked, the boundary cannot be changed. | |
1547 | 1 indicates lock status, 0 indicates unlock status. | |
1548 | ||
9db829f4 BD |
1549 | mtdset= [ARM] |
1550 | ARM/S3C2412 JIVE boot control | |
1551 | ||
1552 | See arch/arm/mach-s3c2412/mach-jive.c | |
1553 | ||
1da177e4 | 1554 | mtouchusb.raw_coordinates= |
a9913044 RD |
1555 | [HW] Make the MicroTouch USB driver use raw coordinates |
1556 | ('y', default) or cooked coordinates ('n') | |
1da177e4 | 1557 | |
0cb55ad2 | 1558 | mtrr_chunk_size=nn[KMG] [X86] |
19f59460 | 1559 | used for mtrr cleanup. It is largest continuous chunk |
0cb55ad2 RD |
1560 | that could hold holes aka. UC entries. |
1561 | ||
1562 | mtrr_gran_size=nn[KMG] [X86] | |
1563 | Used for mtrr cleanup. It is granularity of mtrr block. | |
1564 | Default is 1. | |
1565 | Large value could prevent small alignment from | |
1566 | using up MTRRs. | |
1567 | ||
1568 | mtrr_spare_reg_nr=n [X86] | |
1569 | Format: <integer> | |
1570 | Range: 0,7 : spare reg number | |
1571 | Default : 1 | |
1572 | Used for mtrr cleanup. It is spare mtrr entries number. | |
1573 | Set to 2 or more if your graphical card needs more. | |
1574 | ||
1da177e4 LT |
1575 | n2= [NET] SDL Inc. RISCom/N2 synchronous serial card |
1576 | ||
1577 | NCR_D700= [HW,SCSI] | |
1578 | See header of drivers/scsi/NCR_D700.c. | |
1579 | ||
1580 | ncr5380= [HW,SCSI] | |
1581 | ||
1582 | ncr53c400= [HW,SCSI] | |
1583 | ||
1584 | ncr53c400a= [HW,SCSI] | |
1585 | ||
1586 | ncr53c406a= [HW,SCSI] | |
1587 | ||
1588 | ncr53c8xx= [HW,SCSI] | |
1589 | ||
1590 | netdev= [NET] Network devices parameters | |
1591 | Format: <irq>,<io>,<mem_start>,<mem_end>,<name> | |
1592 | Note that mem_start is often overloaded to mean | |
1593 | something different and driver-specific. | |
a9913044 RD |
1594 | This usage is only documented in each driver source |
1595 | file if at all. | |
1596 | ||
58401572 KPO |
1597 | nf_conntrack.acct= |
1598 | [NETFILTER] Enable connection tracking flow accounting | |
1599 | 0 to disable accounting | |
1600 | 1 to enable accounting | |
1601 | Default value depends on CONFIG_NF_CT_ACCT that is | |
1602 | going to be removed in 2.6.29. | |
1603 | ||
1da177e4 | 1604 | nfsaddrs= [NFS] |
dc7a0816 | 1605 | See Documentation/filesystems/nfs/nfsroot.txt. |
1da177e4 LT |
1606 | |
1607 | nfsroot= [NFS] nfs root filesystem for disk-less boxes. | |
dc7a0816 | 1608 | See Documentation/filesystems/nfs/nfsroot.txt. |
1da177e4 | 1609 | |
a72b4422 TM |
1610 | nfs.callback_tcpport= |
1611 | [NFS] set the TCP port on which the NFSv4 callback | |
1612 | channel should listen. | |
1613 | ||
e571cbf1 TM |
1614 | nfs.cache_getent= |
1615 | [NFS] sets the pathname to the program which is used | |
1616 | to update the NFS client cache entries. | |
1617 | ||
1618 | nfs.cache_getent_timeout= | |
1619 | [NFS] sets the timeout after which an attempt to | |
1620 | update a cache entry is deemed to have failed. | |
1621 | ||
58df095b TM |
1622 | nfs.idmap_cache_timeout= |
1623 | [NFS] set the maximum lifetime for idmapper cache | |
1624 | entries. | |
1625 | ||
f43bf0be TM |
1626 | nfs.enable_ino64= |
1627 | [NFS] enable 64-bit inode numbers. | |
1628 | If zero, the NFS client will fake up a 32-bit inode | |
1629 | number for the readdir() and stat() syscalls instead | |
1630 | of returning the full 64-bit number. | |
1631 | The default is to return 64-bit inode numbers. | |
1632 | ||
1e1030dc | 1633 | nmi_debug= [KNL,AVR32,SH] Specify one or more actions to take |
e7ba176b HS |
1634 | when a NMI is triggered. |
1635 | Format: [state][,regs][,debounce][,die] | |
1636 | ||
6cececfc | 1637 | nmi_watchdog= [KNL,BUGS=X86] Debugging features for SMP kernels |
5b9a0e14 CG |
1638 | Format: [panic,][num] |
1639 | Valid num: 0,1,2 | |
1640 | 0 - turn nmi_watchdog off | |
1641 | 1 - use the IO-APIC timer for the NMI watchdog | |
1642 | 2 - use the local APIC for the NMI watchdog using | |
0cb55ad2 RD |
1643 | a performance counter. Note: This will use one |
1644 | performance counter and the local APIC's performance | |
1645 | vector. | |
1646 | When panic is specified, panic when an NMI watchdog | |
1647 | timeout occurs. | |
1648 | This is useful when you use a panic=... timeout and | |
1649 | need the box quickly up again. | |
5b9a0e14 CG |
1650 | Instead of 1 and 2 it is possible to use the following |
1651 | symbolic names: lapic and ioapic | |
1652 | Example: nmi_watchdog=2 or nmi_watchdog=panic,lapic | |
1da177e4 | 1653 | |
bff38771 AV |
1654 | netpoll.carrier_timeout= |
1655 | [NET] Specifies amount of time (in seconds) that | |
1656 | netpoll should wait for a carrier. By default netpoll | |
1657 | waits 4 seconds. | |
1658 | ||
cd4f0ef7 | 1659 | no387 [BUGS=X86-32] Tells the kernel to use the 387 maths |
1da177e4 LT |
1660 | emulation library even if a 387 maths coprocessor |
1661 | is present. | |
1662 | ||
0cb55ad2 RD |
1663 | no_console_suspend |
1664 | [HW] Never suspend the console | |
1665 | Disable suspending of consoles during suspend and | |
1666 | hibernate operations. Once disabled, debugging | |
1667 | messages can reach various consoles while the rest | |
1668 | of the system is being put to sleep (ie, while | |
1669 | debugging driver suspend/resume hooks). This may | |
1670 | not work reliably with all consoles, but is known | |
1671 | to work with serial and VGA consoles. | |
1672 | ||
c1aee215 CL |
1673 | noaliencache [MM, NUMA, SLAB] Disables the allocation of alien |
1674 | caches in the slab allocator. Saves per-node memory, | |
1675 | but will impact performance. | |
3395ee05 | 1676 | |
a9913044 RD |
1677 | noalign [KNL,ARM] |
1678 | ||
1da177e4 LT |
1679 | noapic [SMP,APIC] Tells the kernel to not make use of any |
1680 | IOAPICs that may be present in the system. | |
1681 | ||
1da177e4 LT |
1682 | nobats [PPC] Do not use BATs for mapping kernel lowmem |
1683 | on "Classic" PPC cores. | |
1684 | ||
1685 | nocache [ARM] | |
a9913044 | 1686 | |
0cb55ad2 RD |
1687 | noclflush [BUGS=X86] Don't use the CLFLUSH instruction |
1688 | ||
163ecdff SN |
1689 | nodelayacct [KNL] Disable per-task delay accounting |
1690 | ||
1da177e4 LT |
1691 | nodisconnect [HW,SCSI,M68K] Disables SCSI disconnects. |
1692 | ||
6902aa84 PM |
1693 | nodsp [SH] Disable hardware DSP at boot time. |
1694 | ||
6cececfc | 1695 | noefi [X86] Disable EFI runtime services support. |
8b2cb7a8 | 1696 | |
1da177e4 LT |
1697 | noexec [IA-64] |
1698 | ||
6cececfc | 1699 | noexec [X86] |
f5a1b191 | 1700 | On X86-32 available only on PAE configured kernels. |
1da177e4 | 1701 | noexec=on: enable non-executable mappings (default) |
f5a1b191 JS |
1702 | noexec=off: disable non-executable mappings |
1703 | ||
1704 | noexec32 [X86-64] | |
1705 | This affects only 32-bit executables. | |
1706 | noexec32=on: enable non-executable mappings (default) | |
1707 | read doesn't imply executable mappings | |
1708 | noexec32=off: disable non-executable mappings | |
1709 | read implies executable mappings | |
1da177e4 | 1710 | |
6902aa84 PM |
1711 | nofpu [SH] Disable hardware FPU at boot time. |
1712 | ||
cd4f0ef7 | 1713 | nofxsr [BUGS=X86-32] Disables x86 floating point extended |
4f886511 CE |
1714 | register save and restore. The kernel will only save |
1715 | legacy floating-point registers on task switch. | |
1da177e4 | 1716 | |
0c752a93 SS |
1717 | noxsave [BUGS=X86] Disables x86 extended register state save |
1718 | and restore using xsave. The kernel will fallback to | |
1719 | enabling legacy floating-point and sse state. | |
1720 | ||
01a24d2b PZ |
1721 | nohlt [BUGS=ARM,SH] Tells the kernel that the sleep(SH) or |
1722 | wfi(ARM) instruction doesn't work correctly and not to | |
1723 | use it. This is also useful when using JTAG debugger. | |
a9913044 | 1724 | |
cd4f0ef7 | 1725 | no-hlt [BUGS=X86-32] Tells the kernel that the hlt |
1da177e4 LT |
1726 | instruction doesn't work correctly and not to |
1727 | use it. | |
1728 | ||
1f29fae2 SH |
1729 | no_file_caps Tells the kernel not to honor file capabilities. The |
1730 | only way then for a file to be executed with privilege | |
1731 | is to be setuid root or executed by root. | |
1732 | ||
1da177e4 LT |
1733 | nohalt [IA-64] Tells the kernel not to use the power saving |
1734 | function PAL_HALT_LIGHT when idle. This increases | |
1735 | power-consumption. On the positive side, it reduces | |
1736 | interrupt wake-up latency, which may improve performance | |
1737 | in certain environments such as networked servers or | |
1738 | real-time systems. | |
1739 | ||
79bf2bb3 TG |
1740 | nohz= [KNL] Boottime enable/disable dynamic ticks |
1741 | Valid arguments: on, off | |
1742 | Default: on | |
1743 | ||
eeee7853 PM |
1744 | noiotrap [SH] Disables trapped I/O port accesses. |
1745 | ||
cd4f0ef7 | 1746 | noirqdebug [X86-32] Disables the code which attempts to detect and |
1da177e4 LT |
1747 | disable unhandled interrupt sources. |
1748 | ||
6cececfc | 1749 | no_timer_check [X86,APIC] Disables the code which tests for |
8542b200 ZA |
1750 | broken timer IRQ sources. |
1751 | ||
1da177e4 LT |
1752 | noisapnp [ISAPNP] Disables ISA PnP code. |
1753 | ||
1754 | noinitrd [RAM] Tells the kernel not to load any configured | |
1755 | initial RAM disk. | |
1756 | ||
03ea8155 WH |
1757 | nointremap [X86-64, Intel-IOMMU] Do not enable interrupt |
1758 | remapping. | |
1759 | ||
1da177e4 LT |
1760 | nointroute [IA-64] |
1761 | ||
0aa366f3 TL |
1762 | nojitter [IA64] Disables jitter checking for ITC timers. |
1763 | ||
cd4f0ef7 | 1764 | nolapic [X86-32,APIC] Do not enable or use the local APIC. |
1da177e4 | 1765 | |
cd4f0ef7 | 1766 | nolapic_timer [X86-32,APIC] Do not use the local APIC timer. |
ad62ca2b | 1767 | |
1da177e4 LT |
1768 | noltlbs [PPC] Do not use large page/tlb entries for kernel |
1769 | lowmem mapping on PPC40x. | |
1770 | ||
312f1f01 H |
1771 | nomca [IA-64] Disable machine check abort handling |
1772 | ||
cd4f0ef7 | 1773 | nomce [X86-32] Machine Check Exception |
abe37e5a | 1774 | |
83d7384f AS |
1775 | nomfgpt [X86-32] Disable Multi-Function General Purpose |
1776 | Timer usage (for AMD Geode machines). | |
1777 | ||
016ddd9b JK |
1778 | nopat [X86] Disable PAT (page attribute table extension of |
1779 | pagetables) support. | |
1780 | ||
0cb55ad2 RD |
1781 | norandmaps Don't use address space randomization. Equivalent to |
1782 | echo 0 > /proc/sys/kernel/randomize_va_space | |
1783 | ||
cd4f0ef7 | 1784 | noreplace-paravirt [X86-32,PV_OPS] Don't patch paravirt_ops |
959b4fdf | 1785 | |
cd4f0ef7 | 1786 | noreplace-smp [X86-32,SMP] Don't replace SMP instructions |
b7fb4af0 JF |
1787 | with UP alternatives |
1788 | ||
1da177e4 LT |
1789 | noresidual [PPC] Don't use residual data on PReP machines. |
1790 | ||
a9913044 RD |
1791 | noresume [SWSUSP] Disables resume and restores original swap |
1792 | space. | |
1793 | ||
1da177e4 LT |
1794 | no-scroll [VGA] Disables scrollback. |
1795 | This is required for the Braillex ib80-piezo Braille | |
1796 | reader made by F.H. Papenmeier (Germany). | |
1797 | ||
1798 | nosbagart [IA-64] | |
1799 | ||
cd4f0ef7 | 1800 | nosep [BUGS=X86-32] Disables x86 SYSENTER/SYSEXIT support. |
4f886511 | 1801 | |
61ec7567 LB |
1802 | nosmp [SMP] Tells an SMP kernel to act as a UP kernel, |
1803 | and disable the IO APIC. legacy for "maxcpus=0". | |
1da177e4 | 1804 | |
97842216 DJ |
1805 | nosoftlockup [KNL] Disable the soft-lockup detector. |
1806 | ||
c077719b | 1807 | noswapaccount [KNL] Disable accounting of swap in memory resource |
21acb9ca | 1808 | controller. (See Documentation/cgroups/memory.txt) |
c077719b | 1809 | |
1da177e4 LT |
1810 | nosync [HW,M68K] Disables sync negotiation for all devices. |
1811 | ||
cd4f0ef7 | 1812 | notsc [BUGS=X86-32] Disable Time Stamp Counter |
1da177e4 LT |
1813 | |
1814 | nousb [USB] Disable the USB subsystem | |
1815 | ||
1816 | nowb [ARM] | |
a9913044 | 1817 | |
2b2fd87a WH |
1818 | nox2apic [X86-64,APIC] Do not enable x2APIC mode. |
1819 | ||
a6c75b86 FY |
1820 | nptcg= [IA64] Override max number of concurrent global TLB |
1821 | purges which is reported from either PAL_VM_SUMMARY or | |
1822 | SAL PALO. | |
1823 | ||
2b633e3f YL |
1824 | nr_cpus= [SMP] Maximum number of processors that an SMP kernel |
1825 | could support. nr_cpus=n : n >= 1 limits the kernel to | |
1826 | supporting 'n' processors. Later in runtime you can not | |
1827 | use hotplug cpu feature to put more cpu back to online. | |
1828 | just like you compile the kernel NR_CPUS=n | |
1829 | ||
0cb55ad2 RD |
1830 | nr_uarts= [SERIAL] maximum number of UARTs to be registered. |
1831 | ||
f0c0b2b8 KH |
1832 | numa_zonelist_order= [KNL, BOOT] Select zonelist order for NUMA. |
1833 | one of ['zone', 'node', 'default'] can be specified | |
1834 | This can be set from sysctl after boot. | |
1835 | See Documentation/sysctl/vm.txt for details. | |
1836 | ||
7c4be253 RD |
1837 | ohci1394_dma=early [HW] enable debugging via the ohci1394 driver. |
1838 | See Documentation/debugging-via-ohci1394.txt for more | |
1839 | info. | |
1840 | ||
3ef0e1f8 AS |
1841 | olpc_ec_timeout= [OLPC] ms delay when issuing EC commands |
1842 | Rather than timing out after 20 ms if an EC | |
1843 | command is not properly ACKed, override the length | |
1844 | of the timeout. We have interrupts disabled while | |
1845 | waiting for the ACK, so if this is set too high | |
1846 | interrupts *may* be lost! | |
1847 | ||
15ac7afe TL |
1848 | omap_mux= [OMAP] Override bootloader pin multiplexing. |
1849 | Format: <mux_mode0.mode_name=value>... | |
1850 | For example, to override I2C bus2: | |
1851 | omap_mux=i2c2_scl.i2c2_scl=0x100,i2c2_sda.i2c2_sda=0x100 | |
1852 | ||
1da177e4 LT |
1853 | opl3= [HW,OSS] |
1854 | Format: <io> | |
1855 | ||
1da177e4 LT |
1856 | oprofile.timer= [HW] |
1857 | Use timer interrupt instead of performance counters | |
1858 | ||
7e4e0bd5 RR |
1859 | oprofile.cpu_type= Force an oprofile cpu type |
1860 | This might be useful if you have an older oprofile | |
1861 | userland or if you want common events. | |
8d7ff4f2 RR |
1862 | Format: { arch_perfmon } |
1863 | arch_perfmon: [X86] Force use of architectural | |
7e4e0bd5 RR |
1864 | perfmon on Intel CPUs instead of the |
1865 | CPU specific event set. | |
1dcdb5a9 | 1866 | |
1da177e4 LT |
1867 | osst= [HW,SCSI] SCSI Tape Driver |
1868 | Format: <buffer_size>,<write_threshold> | |
1869 | See also Documentation/scsi/st.txt. | |
1870 | ||
1871 | panic= [KNL] Kernel behaviour on panic | |
1872 | Format: <timeout> | |
1873 | ||
1874 | parkbd.port= [HW] Parallel port number the keyboard adapter is | |
1875 | connected to, default is 0. | |
1876 | Format: <parport#> | |
1877 | parkbd.mode= [HW] Parallel port keyboard adapter mode of operation, | |
1878 | 0 for XT, 1 for AT (default is AT). | |
a9913044 RD |
1879 | Format: <mode> |
1880 | ||
1881 | parport= [HW,PPT] Specify parallel ports. 0 disables. | |
1882 | Format: { 0 | auto | 0xBBB[,IRQ[,DMA]] } | |
1883 | Use 'auto' to force the driver to use any | |
1884 | IRQ/DMA settings detected (the default is to | |
1885 | ignore detected IRQ/DMA settings because of | |
1886 | possible conflicts). You can specify the base | |
1887 | address, IRQ, and DMA settings; IRQ and DMA | |
1888 | should be numbers, or 'auto' (for using detected | |
1889 | settings on that particular port), or 'nofifo' | |
1890 | (to avoid using a FIFO even if it is detected). | |
1891 | Parallel ports are assigned in the order they | |
1892 | are specified on the command line, starting | |
1893 | with parport0. | |
1894 | ||
1895 | parport_init_mode= [HW,PPT] | |
1896 | Configure VIA parallel port to operate in | |
1897 | a specific mode. This is necessary on Pegasos | |
1898 | computer where firmware has no options for setting | |
1899 | up parallel port mode and sets it to spp. | |
1900 | Currently this function knows 686a and 8231 chips. | |
1da177e4 LT |
1901 | Format: [spp|ps2|epp|ecp|ecpepp] |
1902 | ||
a9913044 RD |
1903 | pas2= [HW,OSS] Format: |
1904 | <io>,<irq>,<dma>,<dma16>,<sb_io>,<sb_irq>,<sb_dma>,<sb_dma16> | |
1905 | ||
1da177e4 LT |
1906 | pas16= [HW,SCSI] |
1907 | See header of drivers/scsi/pas16.c. | |
1908 | ||
dd287796 AM |
1909 | pause_on_oops= |
1910 | Halt all CPUs after the first oops has been printed for | |
1911 | the specified number of seconds. This is to be used if | |
1912 | your oopses keep scrolling off the screen. | |
1913 | ||
1da177e4 LT |
1914 | pcbit= [HW,ISDN] |
1915 | ||
1916 | pcd. [PARIDE] | |
1917 | See header of drivers/block/paride/pcd.c. | |
31c00fc1 | 1918 | See also Documentation/blockdev/paride.txt. |
1da177e4 | 1919 | |
a9913044 | 1920 | pci=option[,option...] [PCI] various PCI subsystem options: |
1cc0ca26 BH |
1921 | earlydump [X86] dump PCI config space before the kernel |
1922 | changes anything | |
c0115606 | 1923 | off [X86] don't probe for the PCI bus |
cd4f0ef7 | 1924 | bios [X86-32] force use of PCI BIOS, don't access |
a9913044 RD |
1925 | the hardware directly. Use this if your machine |
1926 | has a non-standard PCI host bridge. | |
cd4f0ef7 | 1927 | nobios [X86-32] disallow use of PCI BIOS, only direct |
a9913044 RD |
1928 | hardware access methods are allowed. Use this |
1929 | if you experience crashes upon bootup and you | |
1930 | suspect they are caused by the BIOS. | |
c0115606 | 1931 | conf1 [X86] Force use of PCI Configuration |
a9913044 | 1932 | Mechanism 1. |
c0115606 | 1933 | conf2 [X86] Force use of PCI Configuration |
a9913044 | 1934 | Mechanism 2. |
7f785763 RD |
1935 | noaer [PCIE] If the PCIEAER kernel config parameter is |
1936 | enabled, this kernel boot option can be used to | |
1937 | disable the use of PCIE advanced error reporting. | |
32a2eea7 JG |
1938 | nodomains [PCI] Disable support for multiple PCI |
1939 | root domains (aka PCI segments, in ACPI-speak). | |
6cececfc | 1940 | nommconf [X86] Disable use of MMCONFIG for PCI |
61be6d66 | 1941 | Configuration |
12983077 AH |
1942 | check_enable_amd_mmconf [X86] check for and enable |
1943 | properly configured MMIO access to PCI | |
1944 | config space on AMD family 10h CPU | |
309e57df MW |
1945 | nomsi [MSI] If the PCI_MSI kernel config parameter is |
1946 | enabled, this kernel boot option can be used to | |
1947 | disable the use of MSI interrupts system-wide. | |
a9322f64 SA |
1948 | noioapicquirk [APIC] Disable all boot interrupt quirks. |
1949 | Safety option to keep boot IRQs enabled. This | |
1950 | should never be necessary. | |
9197979b SA |
1951 | ioapicreroute [APIC] Enable rerouting of boot IRQs to the |
1952 | primary IO-APIC for bridges that cannot disable | |
1953 | boot IRQs. This fixes a source of spurious IRQs | |
1954 | when the system masks IRQs. | |
41b9eb26 SA |
1955 | noioapicreroute [APIC] Disable workaround that uses the |
1956 | boot IRQ equivalent of an IRQ that connects to | |
1957 | a chipset where boot IRQs cannot be disabled. | |
1958 | The opposite of ioapicreroute. | |
cd4f0ef7 | 1959 | biosirq [X86-32] Use PCI BIOS calls to get the interrupt |
a9913044 RD |
1960 | routing table. These calls are known to be buggy |
1961 | on several machines and they hang the machine | |
1962 | when used, but on other computers it's the only | |
1963 | way to get the interrupt routing table. Try | |
1964 | this option if the kernel is unable to allocate | |
1965 | IRQs or discover secondary PCI buses on your | |
1966 | motherboard. | |
c0115606 | 1967 | rom [X86] Assign address space to expansion ROMs. |
a9913044 RD |
1968 | Use with caution as certain devices share |
1969 | address decoders between ROMs and other | |
1970 | resources. | |
c0115606 | 1971 | norom [X86] Do not assign address space to |
bb71ad88 GH |
1972 | expansion ROMs that do not already have |
1973 | BIOS assigned address ranges. | |
c0115606 | 1974 | irqmask=0xMMMM [X86] Set a bit mask of IRQs allowed to be |
a9913044 RD |
1975 | assigned automatically to PCI devices. You can |
1976 | make the kernel exclude IRQs of your ISA cards | |
1977 | this way. | |
c0115606 | 1978 | pirqaddr=0xAAAAA [X86] Specify the physical address |
a9913044 RD |
1979 | of the PIRQ table (normally generated |
1980 | by the BIOS) if it is outside the | |
1981 | F0000h-100000h range. | |
c0115606 | 1982 | lastbus=N [X86] Scan all buses thru bus #N. Can be |
a9913044 RD |
1983 | useful if the kernel is unable to find your |
1984 | secondary buses and you want to tell it | |
1985 | explicitly which ones they are. | |
c0115606 | 1986 | assign-busses [X86] Always assign all PCI bus |
a9913044 RD |
1987 | numbers ourselves, overriding |
1988 | whatever the firmware may have done. | |
c0115606 | 1989 | usepirqmask [X86] Honor the possible IRQ mask stored |
a9913044 RD |
1990 | in the BIOS $PIR table. This is needed on |
1991 | some systems with broken BIOSes, notably | |
1992 | some HP Pavilion N5400 and Omnibook XE3 | |
1993 | notebooks. This will have no effect if ACPI | |
1994 | IRQ routing is enabled. | |
c0115606 | 1995 | noacpi [X86] Do not use ACPI for IRQ routing |
a9913044 | 1996 | or for PCI scanning. |
7bc5e3f2 BH |
1997 | use_crs [X86] Use PCI host bridge window information |
1998 | from ACPI. On BIOSes from 2008 or later, this | |
1999 | is enabled by default. If you need to use this, | |
2000 | please report a bug. | |
2001 | nocrs [X86] Ignore PCI host bridge windows from ACPI. | |
2002 | If you need to use this, please report a bug. | |
a9913044 RD |
2003 | routeirq Do IRQ routing for all PCI devices. |
2004 | This is normally done in pci_enable_device(), | |
2005 | so this option is a temporary workaround | |
2006 | for broken drivers that don't call it. | |
13a6ddb0 YL |
2007 | skip_isa_align [X86] do not align io start addr, so can |
2008 | handle more pci cards | |
a9913044 RD |
2009 | firmware [ARM] Do not re-enumerate the bus but instead |
2010 | just use the configuration from the | |
2011 | bootloader. This is currently used on | |
2012 | IXP2000 systems where the bus has to be | |
2013 | configured a certain way for adjunct CPUs. | |
0637a70a AK |
2014 | noearly [X86] Don't do any early type 1 scanning. |
2015 | This might help on some broken boards which | |
2016 | machine check when some devices' config space | |
2017 | is read. But various workarounds are disabled | |
2018 | and some IOMMU drivers will not work. | |
6b4b78fe MD |
2019 | bfsort Sort PCI devices into breadth-first order. |
2020 | This sorting is done to get a device | |
2021 | order compatible with older (<= 2.4) kernels. | |
2022 | nobfsort Don't sort PCI devices into breadth-first order. | |
4516a618 AN |
2023 | cbiosize=nn[KMG] The fixed amount of bus space which is |
2024 | reserved for the CardBus bridge's IO window. | |
2025 | The default value is 256 bytes. | |
2026 | cbmemsize=nn[KMG] The fixed amount of bus space which is | |
2027 | reserved for the CardBus bridge's memory | |
2028 | window. The default value is 64 megabytes. | |
32a9a682 YS |
2029 | resource_alignment= |
2030 | Format: | |
2031 | [<order of align>@][<domain>:]<bus>:<slot>.<func>[; ...] | |
2032 | Specifies alignment and device to reassign | |
2033 | aligned memory resources. | |
2034 | If <order of align> is not specified, | |
2035 | PAGE_SIZE is used as alignment. | |
2036 | PCI-PCI bridge can be specified, if resource | |
2037 | windows need to be expanded. | |
43c16408 AP |
2038 | ecrc= Enable/disable PCIe ECRC (transaction layer |
2039 | end-to-end CRC checking). | |
2040 | bios: Use BIOS/firmware settings. This is the | |
2041 | the default. | |
2042 | off: Turn ECRC off | |
2043 | on: Turn ECRC on. | |
6b4b78fe | 2044 | |
e5665a45 CE |
2045 | pcie_aspm= [PCIE] Forcibly enable or disable PCIe Active State Power |
2046 | Management. | |
2047 | off Disable ASPM. | |
2048 | force Enable ASPM even on devices that claim not to support it. | |
2049 | WARNING: Forcing ASPM on may cause system lockups. | |
2050 | ||
c7f48656 | 2051 | pcie_pme= [PCIE,PM] Native PCIe PME signaling options: |
b27759f8 RW |
2052 | Format: {auto|force}[,nomsi] |
2053 | auto Use native PCIe PME signaling if the BIOS allows the | |
2054 | kernel to control PCIe config registers of root ports. | |
c7f48656 RW |
2055 | force Use native PCIe PME signaling even if the BIOS refuses |
2056 | to allow the kernel to control the relevant PCIe config | |
2057 | registers. | |
c39fae14 RW |
2058 | nomsi Do not use MSI for native PCIe PME signaling (this makes |
2059 | all PCIe root ports use INTx for everything). | |
c7f48656 | 2060 | |
1da177e4 LT |
2061 | pcmv= [HW,PCMCIA] BadgePAD 4 |
2062 | ||
2063 | pd. [PARIDE] | |
31c00fc1 | 2064 | See Documentation/blockdev/paride.txt. |
1da177e4 LT |
2065 | |
2066 | pdcchassis= [PARISC,HW] Disable/Enable PDC Chassis Status codes at | |
2067 | boot time. | |
2068 | Format: { 0 | 1 } | |
2069 | See arch/parisc/kernel/pdc_chassis.c | |
2070 | ||
f58dc01b | 2071 | percpu_alloc= Select which percpu first chunk allocator to use. |
e933a73f TH |
2072 | Currently supported values are "embed" and "page". |
2073 | Archs may support subset or none of the selections. | |
2074 | See comments in mm/percpu.c for details on each | |
2075 | allocator. This parameter is primarily for debugging | |
2076 | and performance comparison. | |
fa8a7094 | 2077 | |
1da177e4 | 2078 | pf. [PARIDE] |
31c00fc1 | 2079 | See Documentation/blockdev/paride.txt. |
1da177e4 LT |
2080 | |
2081 | pg. [PARIDE] | |
31c00fc1 | 2082 | See Documentation/blockdev/paride.txt. |
1da177e4 LT |
2083 | |
2084 | pirq= [SMP,APIC] Manual mp-table setup | |
71cced6e | 2085 | See Documentation/x86/i386/IO-APIC.txt. |
1da177e4 LT |
2086 | |
2087 | plip= [PPT,NET] Parallel port network link | |
2088 | Format: { parport<nr> | timid | 0 } | |
2089 | See also Documentation/parport.txt. | |
2090 | ||
de32a243 TG |
2091 | pmtmr= [X86] Manual setup of pmtmr I/O Port. |
2092 | Override pmtimer IOPort with a hex value. | |
2093 | e.g. pmtmr=0x508 | |
2094 | ||
97ef062b BH |
2095 | pnp.debug [PNP] |
2096 | Enable PNP debug messages. This depends on the | |
2097 | CONFIG_PNP_DEBUG_MESSAGES option. | |
2098 | ||
1da177e4 LT |
2099 | pnpacpi= [ACPI] |
2100 | { off } | |
2101 | ||
2102 | pnpbios= [ISAPNP] | |
2103 | { on | off | curr | res | no-curr | no-res } | |
2104 | ||
2105 | pnp_reserve_irq= | |
2106 | [ISAPNP] Exclude IRQs for the autoconfiguration | |
2107 | ||
2108 | pnp_reserve_dma= | |
2109 | [ISAPNP] Exclude DMAs for the autoconfiguration | |
2110 | ||
2111 | pnp_reserve_io= [ISAPNP] Exclude I/O ports for the autoconfiguration | |
a9913044 | 2112 | Ranges are in pairs (I/O port base and size). |
1da177e4 LT |
2113 | |
2114 | pnp_reserve_mem= | |
a9913044 RD |
2115 | [ISAPNP] Exclude memory regions for the |
2116 | autoconfiguration. | |
1da177e4 LT |
2117 | Ranges are in pairs (memory base and size). |
2118 | ||
4af94f39 RD |
2119 | ports= [IP_VS_FTP] IPVS ftp helper module |
2120 | Default is 21. | |
2121 | Up to 8 (IP_VS_APP_MAX_PORTS) ports | |
2122 | may be specified. | |
2123 | Format: <port>,<port>.... | |
2124 | ||
45807a1d IM |
2125 | print-fatal-signals= |
2126 | [KNL] debug: print fatal signals | |
f84d49b2 NO |
2127 | |
2128 | If enabled, warn about various signal handling | |
2129 | related application anomalies: too many signals, | |
2130 | too many POSIX.1 timers, fatal signals causing a | |
2131 | coredump - etc. | |
2132 | ||
2133 | If you hit the warning due to signal overflow, | |
2134 | you might want to try "ulimit -i unlimited". | |
2135 | ||
45807a1d IM |
2136 | default: off. |
2137 | ||
e84845c4 RD |
2138 | printk.time= Show timing data prefixed to each printk message line |
2139 | Format: <bool> (1/Y/y=enable, 0/N/n=disable) | |
2140 | ||
0cb55ad2 RD |
2141 | processor.max_cstate= [HW,ACPI] |
2142 | Limit processor to maximum C-state | |
2143 | max_cstate=9 overrides any DMI blacklist limit. | |
2144 | ||
2145 | processor.nocst [HW,ACPI] | |
2146 | Ignore the _CST method to determine C-states, | |
2147 | instead using the legacy FADT method | |
2148 | ||
1da177e4 | 2149 | profile= [KNL] Enable kernel profiling via /proc/profile |
a9913044 RD |
2150 | Format: [schedule,]<number> |
2151 | Param: "schedule" - profile schedule points. | |
2152 | Param: <number> - step/bucket size as a power of 2 for | |
2153 | statistical time based profiling. | |
b3da2a73 MG |
2154 | Param: "sleep" - profile D-state sleeping (millisecs). |
2155 | Requires CONFIG_SCHEDSTATS | |
c0fe2e69 | 2156 | Param: "kvm" - profile VM exits. |
1da177e4 | 2157 | |
1da177e4 LT |
2158 | prompt_ramdisk= [RAM] List of RAM disks to prompt for floppy disk |
2159 | before loading. | |
31c00fc1 | 2160 | See Documentation/blockdev/ramdisk.txt. |
1da177e4 | 2161 | |
a9913044 RD |
2162 | psmouse.proto= [HW,MOUSE] Highest PS2 mouse protocol extension to |
2163 | probe for; one of (bare|imps|exps|lifebook|any). | |
1da177e4 LT |
2164 | psmouse.rate= [HW,MOUSE] Set desired mouse report rate, in reports |
2165 | per second. | |
a9913044 RD |
2166 | psmouse.resetafter= [HW,MOUSE] |
2167 | Try to reset the device after so many bad packets | |
1da177e4 LT |
2168 | (0 = never). |
2169 | psmouse.resolution= | |
2170 | [HW,MOUSE] Set desired mouse resolution, in dpi. | |
2171 | psmouse.smartscroll= | |
a9913044 | 2172 | [HW,MOUSE] Controls Logitech smartscroll autorepeat. |
1da177e4 LT |
2173 | 0 = disabled, 1 = enabled (default). |
2174 | ||
2175 | pss= [HW,OSS] Personal Sound System (ECHO ESC614) | |
a9913044 RD |
2176 | Format: |
2177 | <io>,<mss_io>,<mss_irq>,<mss_dma>,<mpu_io>,<mpu_irq> | |
1da177e4 LT |
2178 | |
2179 | pt. [PARIDE] | |
31c00fc1 | 2180 | See Documentation/blockdev/paride.txt. |
1da177e4 | 2181 | |
dc8c8587 KS |
2182 | pty.legacy_count= |
2183 | [KNL] Number of legacy pty's. Overwrites compiled-in | |
2184 | default number. | |
2185 | ||
7d2c502f | 2186 | quiet [KNL] Disable most log messages |
a9913044 | 2187 | |
1da177e4 LT |
2188 | r128= [HW,DRM] |
2189 | ||
2190 | raid= [HW,RAID] | |
2191 | See Documentation/md.txt. | |
2192 | ||
a9913044 | 2193 | ramdisk_blocksize= [RAM] |
31c00fc1 | 2194 | See Documentation/blockdev/ramdisk.txt. |
a9913044 | 2195 | |
1da177e4 | 2196 | ramdisk_size= [RAM] Sizes of RAM disks in kilobytes |
31c00fc1 | 2197 | See Documentation/blockdev/ramdisk.txt. |
1da177e4 | 2198 | |
24aaef8d RD |
2199 | rcupdate.blimit= [KNL,BOOT] |
2200 | Set maximum number of finished RCU callbacks to process | |
2201 | in one batch. | |
21a1ea9e | 2202 | |
24aaef8d RD |
2203 | rcupdate.qhimark= [KNL,BOOT] |
2204 | Set threshold of queued | |
21a1ea9e DS |
2205 | RCU callbacks over which batch limiting is disabled. |
2206 | ||
24aaef8d RD |
2207 | rcupdate.qlowmark= [KNL,BOOT] |
2208 | Set threshold of queued RCU callbacks below which | |
2209 | batch limiting is re-enabled. | |
21a1ea9e | 2210 | |
ffdfc409 OJ |
2211 | rdinit= [KNL] |
2212 | Format: <full_path> | |
2213 | Run specified binary instead of /init from the ramdisk, | |
2214 | used for early userspace startup. See initrd. | |
2215 | ||
cd4f0ef7 | 2216 | reboot= [BUGS=X86-32,BUGS=ARM,BUGS=IA-64] Rebooting mode |
1da177e4 | 2217 | Format: <reboot_mode>[,<reboot_mode2>[,...]] |
ecb08d81 | 2218 | See arch/*/kernel/reboot.c or arch/*/kernel/process.c |
1da177e4 | 2219 | |
46b6d94e PJ |
2220 | relax_domain_level= |
2221 | [KNL, SMP] Set scheduler's default relax_domain_level. | |
21acb9ca | 2222 | See Documentation/cgroups/cpusets.txt. |
46b6d94e | 2223 | |
1da177e4 LT |
2224 | reserve= [KNL,BUGS] Force the kernel to ignore some iomem area |
2225 | ||
cd4f0ef7 | 2226 | reservetop= [X86-32] |
461a9aff ZA |
2227 | Format: nn[KMG] |
2228 | Reserves a hole at the top of the kernel virtual | |
2229 | address space. | |
2230 | ||
7e96287d VG |
2231 | reset_devices [KNL] Force drivers to reset the underlying device |
2232 | during initialization. | |
2233 | ||
a9913044 RD |
2234 | resume= [SWSUSP] |
2235 | Specify the partition device for software suspend | |
1da177e4 | 2236 | |
ecbd0da1 RW |
2237 | resume_offset= [SWSUSP] |
2238 | Specify the offset from the beginning of the partition | |
2239 | given by "resume=" at which the swap header is located, | |
2240 | in <PAGE_SIZE> units (needed only for swap files). | |
2241 | See Documentation/power/swsusp-and-swap-files.txt | |
2242 | ||
0a7b35cb MN |
2243 | retain_initrd [RAM] Keep initrd memory after extraction |
2244 | ||
1da177e4 LT |
2245 | rhash_entries= [KNL,NET] |
2246 | Set number of hash buckets for route cache | |
2247 | ||
2248 | riscom8= [HW,SERIAL] | |
2249 | Format: <io_board1>[,<io_board2>[,...<io_boardN>]] | |
2250 | ||
2251 | ro [KNL] Mount root device read-only on boot | |
2252 | ||
2253 | root= [KNL] Root filesystem | |
2254 | ||
2255 | rootdelay= [KNL] Delay (in seconds) to pause before attempting to | |
2256 | mount the root filesystem | |
2257 | ||
2258 | rootflags= [KNL] Set root filesystem mount option string | |
2259 | ||
2260 | rootfstype= [KNL] Set root filesystem type | |
2261 | ||
cc1ed754 PO |
2262 | rootwait [KNL] Wait (indefinitely) for root device to show up. |
2263 | Useful for devices that are detected asynchronously | |
2264 | (e.g. USB and MMC devices). | |
2265 | ||
1da177e4 LT |
2266 | rw [KNL] Mount root device read-write on boot |
2267 | ||
2268 | S [KNL] Run init in single mode | |
2269 | ||
2270 | sa1100ir [NET] | |
2271 | See drivers/net/irda/sa1100_ir.c. | |
2272 | ||
1da177e4 | 2273 | sbni= [NET] Granch SBNI12 leased line adapter |
a9913044 | 2274 | |
f6630114 MT |
2275 | sched_debug [KNL] Enables verbose scheduler debug messages. |
2276 | ||
1da177e4 LT |
2277 | scsi_debug_*= [SCSI] |
2278 | See drivers/scsi/scsi_debug.c. | |
2279 | ||
2280 | scsi_default_dev_flags= | |
2281 | [SCSI] SCSI default device flags | |
2282 | Format: <integer> | |
2283 | ||
2284 | scsi_dev_flags= [SCSI] Black/white list entry for vendor and model | |
2285 | Format: <vendor>:<model>:<flags> | |
2286 | (flags are integer value) | |
2287 | ||
6af6632a RD |
2288 | scsi_logging_level= [SCSI] a bit mask of logging levels |
2289 | See drivers/scsi/scsi_logging.h for bits. Also | |
2290 | settable via sysctl at dev.scsi.logging_level | |
2291 | (/proc/sys/dev/scsi/logging_level). | |
2292 | There is also a nice 'scsi_logging_level' script in the | |
2293 | S390-tools package, available for download at | |
2294 | http://www-128.ibm.com/developerworks/linux/linux390/s390-tools-1.5.4.html | |
1da177e4 | 2295 | |
3e082a91 MW |
2296 | scsi_mod.scan= [SCSI] sync (default) scans SCSI busses as they are |
2297 | discovered. async scans them in kernel threads, | |
2298 | allowing boot to proceed. none ignores them, expecting | |
2299 | user space to do the scan. | |
2300 | ||
0cb55ad2 RD |
2301 | security= [SECURITY] Choose a security module to enable at boot. |
2302 | If this boot parameter is not specified, only the first | |
2303 | security module asking for security registration will be | |
2304 | loaded. An invalid security module name will be treated | |
2305 | as if no module has been chosen. | |
2306 | ||
2307 | selinux= [SELINUX] Disable or enable SELinux at boot time. | |
1da177e4 LT |
2308 | Format: { "0" | "1" } |
2309 | See security/selinux/Kconfig help text. | |
2310 | 0 -- disable. | |
2311 | 1 -- enable. | |
2312 | Default value is set via kernel config option. | |
2313 | If enabled at boot time, /selinux/disable can be used | |
2314 | later to disable prior to initial policy load. | |
2315 | ||
cd4f0ef7 | 2316 | serialnumber [BUGS=X86-32] |
1da177e4 | 2317 | |
1da177e4 LT |
2318 | shapers= [NET] |
2319 | Maximal number of shapers. | |
a9913044 | 2320 | |
b05f78f5 YL |
2321 | show_msr= [x86] show boot-time MSR settings |
2322 | Format: { <integer> } | |
2323 | Show boot-time (BIOS-initialized) MSR settings. | |
2324 | The parameter means the number of CPUs to show, | |
2325 | for example 1 means boot CPU only. | |
2326 | ||
1da177e4 LT |
2327 | sim710= [SCSI,HW] |
2328 | See header of drivers/scsi/sim710.c. | |
2329 | ||
2330 | simeth= [IA-64] | |
2331 | simscsi= | |
a9913044 | 2332 | |
1da177e4 LT |
2333 | slram= [HW,MTD] |
2334 | ||
f0630fff CL |
2335 | slub_debug[=options[,slabs]] [MM, SLUB] |
2336 | Enabling slub_debug allows one to determine the | |
2337 | culprit if slab objects become corrupted. Enabling | |
2338 | slub_debug can create guard zones around objects and | |
2339 | may poison objects when not in use. Also tracks the | |
2340 | last alloc / free. For more information see | |
2341 | Documentation/vm/slub.txt. | |
c1aee215 CL |
2342 | |
2343 | slub_max_order= [MM, SLUB] | |
f0630fff CL |
2344 | Determines the maximum allowed order for slabs. |
2345 | A high setting may cause OOMs due to memory | |
2346 | fragmentation. For more information see | |
2347 | Documentation/vm/slub.txt. | |
c1aee215 CL |
2348 | |
2349 | slub_min_objects= [MM, SLUB] | |
f0630fff CL |
2350 | The minimum number of objects per slab. SLUB will |
2351 | increase the slab order up to slub_max_order to | |
2352 | generate a sufficiently large slab able to contain | |
2353 | the number of objects indicated. The higher the number | |
2354 | of objects the smaller the overhead of tracking slabs | |
2355 | and the less frequently locks need to be acquired. | |
c1aee215 CL |
2356 | For more information see Documentation/vm/slub.txt. |
2357 | ||
2358 | slub_min_order= [MM, SLUB] | |
2359 | Determines the mininum page order for slabs. Must be | |
f0630fff | 2360 | lower than slub_max_order. |
c1aee215 CL |
2361 | For more information see Documentation/vm/slub.txt. |
2362 | ||
2363 | slub_nomerge [MM, SLUB] | |
f0630fff | 2364 | Disable merging of slabs with similar size. May be |
c1aee215 | 2365 | necessary if there is some reason to distinguish |
f0630fff CL |
2366 | allocs to different slabs. Debug options disable |
2367 | merging on their own. | |
c1aee215 CL |
2368 | For more information see Documentation/vm/slub.txt. |
2369 | ||
1da177e4 LT |
2370 | smart2= [HW] |
2371 | Format: <io1>[,<io2>[,...,<io8>]] | |
2372 | ||
cd4f0ef7 | 2373 | smp-alt-once [X86-32,SMP] On a hotplug CPU system, only |
b7fb4af0 JF |
2374 | attempt to substitute SMP alternatives once at boot. |
2375 | ||
d0d4f69b BH |
2376 | smsc-ircc2.nopnp [HW] Don't use PNP to discover SMC devices |
2377 | smsc-ircc2.ircc_cfg= [HW] Device configuration I/O port | |
2378 | smsc-ircc2.ircc_sir= [HW] SIR base I/O port | |
2379 | smsc-ircc2.ircc_fir= [HW] FIR base I/O port | |
2380 | smsc-ircc2.ircc_irq= [HW] IRQ line | |
2381 | smsc-ircc2.ircc_dma= [HW] DMA channel | |
2382 | smsc-ircc2.ircc_transceiver= [HW] Transceiver type: | |
2383 | 0: Toshiba Satellite 1800 (GP data pin select) | |
2384 | 1: Fast pin select (default) | |
2385 | 2: ATC IRMode | |
2386 | ||
1da177e4 LT |
2387 | snd-ad1816a= [HW,ALSA] |
2388 | ||
2389 | snd-ad1848= [HW,ALSA] | |
2390 | ||
2391 | snd-ali5451= [HW,ALSA] | |
2392 | ||
2393 | snd-als100= [HW,ALSA] | |
2394 | ||
2395 | snd-als4000= [HW,ALSA] | |
2396 | ||
2397 | snd-azt2320= [HW,ALSA] | |
2398 | ||
2399 | snd-cmi8330= [HW,ALSA] | |
2400 | ||
2401 | snd-cmipci= [HW,ALSA] | |
2402 | ||
2403 | snd-cs4231= [HW,ALSA] | |
2404 | ||
2405 | snd-cs4232= [HW,ALSA] | |
2406 | ||
2407 | snd-cs4236= [HW,ALSA] | |
2408 | ||
2409 | snd-cs4281= [HW,ALSA] | |
2410 | ||
2411 | snd-cs46xx= [HW,ALSA] | |
2412 | ||
2413 | snd-dt019x= [HW,ALSA] | |
2414 | ||
2415 | snd-dummy= [HW,ALSA] | |
2416 | ||
2417 | snd-emu10k1= [HW,ALSA] | |
2418 | ||
2419 | snd-ens1370= [HW,ALSA] | |
2420 | ||
2421 | snd-ens1371= [HW,ALSA] | |
2422 | ||
2423 | snd-es968= [HW,ALSA] | |
2424 | ||
2425 | snd-es1688= [HW,ALSA] | |
2426 | ||
2427 | snd-es18xx= [HW,ALSA] | |
2428 | ||
2429 | snd-es1938= [HW,ALSA] | |
2430 | ||
2431 | snd-es1968= [HW,ALSA] | |
2432 | ||
2433 | snd-fm801= [HW,ALSA] | |
2434 | ||
2435 | snd-gusclassic= [HW,ALSA] | |
2436 | ||
2437 | snd-gusextreme= [HW,ALSA] | |
2438 | ||
2439 | snd-gusmax= [HW,ALSA] | |
2440 | ||
2441 | snd-hdsp= [HW,ALSA] | |
2442 | ||
2443 | snd-ice1712= [HW,ALSA] | |
2444 | ||
2445 | snd-intel8x0= [HW,ALSA] | |
2446 | ||
2447 | snd-interwave= [HW,ALSA] | |
2448 | ||
2449 | snd-interwave-stb= | |
2450 | [HW,ALSA] | |
2451 | ||
2452 | snd-korg1212= [HW,ALSA] | |
2453 | ||
2454 | snd-maestro3= [HW,ALSA] | |
2455 | ||
2456 | snd-mpu401= [HW,ALSA] | |
2457 | ||
2458 | snd-mtpav= [HW,ALSA] | |
2459 | ||
2460 | snd-nm256= [HW,ALSA] | |
2461 | ||
2462 | snd-opl3sa2= [HW,ALSA] | |
2463 | ||
2464 | snd-opti92x-ad1848= | |
2465 | [HW,ALSA] | |
2466 | ||
2467 | snd-opti92x-cs4231= | |
2468 | [HW,ALSA] | |
2469 | ||
2470 | snd-opti93x= [HW,ALSA] | |
2471 | ||
2472 | snd-pmac= [HW,ALSA] | |
2473 | ||
2474 | snd-rme32= [HW,ALSA] | |
2475 | ||
2476 | snd-rme96= [HW,ALSA] | |
2477 | ||
2478 | snd-rme9652= [HW,ALSA] | |
2479 | ||
2480 | snd-sb8= [HW,ALSA] | |
2481 | ||
2482 | snd-sb16= [HW,ALSA] | |
2483 | ||
2484 | snd-sbawe= [HW,ALSA] | |
2485 | ||
2486 | snd-serial= [HW,ALSA] | |
2487 | ||
2488 | snd-sgalaxy= [HW,ALSA] | |
2489 | ||
2490 | snd-sonicvibes= [HW,ALSA] | |
2491 | ||
2492 | snd-sun-amd7930= | |
2493 | [HW,ALSA] | |
2494 | ||
2495 | snd-sun-cs4231= [HW,ALSA] | |
2496 | ||
2497 | snd-trident= [HW,ALSA] | |
2498 | ||
2499 | snd-usb-audio= [HW,ALSA,USB] | |
2500 | ||
2501 | snd-via82xx= [HW,ALSA] | |
2502 | ||
2503 | snd-virmidi= [HW,ALSA] | |
2504 | ||
2505 | snd-wavefront= [HW,ALSA] | |
2506 | ||
2507 | snd-ymfpci= [HW,ALSA] | |
a9913044 | 2508 | |
9c44bc03 IM |
2509 | softlockup_panic= |
2510 | [KNL] Should the soft-lockup detector generate panics. | |
2511 | ||
1da177e4 LT |
2512 | sonypi.*= [HW] Sony Programmable I/O Control Device driver |
2513 | See Documentation/sonypi.txt | |
2514 | ||
2515 | specialix= [HW,SERIAL] Specialix multi-serial port adapter | |
31c00fc1 | 2516 | See Documentation/serial/specialix.txt. |
1da177e4 LT |
2517 | |
2518 | spia_io_base= [HW,MTD] | |
2519 | spia_fio_base= | |
2520 | spia_pedr= | |
2521 | spia_peddr= | |
2522 | ||
2523 | sscape= [HW,OSS] | |
2524 | Format: <io>,<irq>,<dma>,<mpu_io>,<mpu_irq> | |
a9913044 | 2525 | |
1da177e4 LT |
2526 | st= [HW,SCSI] SCSI tape parameters (buffers, etc.) |
2527 | See Documentation/scsi/st.txt. | |
2528 | ||
f38f1d2a SR |
2529 | stacktrace [FTRACE] |
2530 | Enabled the stack tracer on boot up. | |
2531 | ||
1da177e4 LT |
2532 | sti= [PARISC,HW] |
2533 | Format: <num> | |
2534 | Set the STI (builtin display/keyboard on the HP-PARISC | |
2535 | machines) console (graphic card) which should be used | |
2536 | as the initial boot-console. | |
2537 | See also comment in drivers/video/console/sticore.c. | |
2538 | ||
2539 | sti_font= [HW] | |
2540 | See comment in drivers/video/console/sticore.c. | |
2541 | ||
2542 | stifb= [HW] | |
2543 | Format: bpp:<bpp1>[:<bpp2>[:<bpp3>...]] | |
2544 | ||
cbf11071 TM |
2545 | sunrpc.min_resvport= |
2546 | sunrpc.max_resvport= | |
2547 | [NFS,SUNRPC] | |
2548 | SunRPC servers often require that client requests | |
2549 | originate from a privileged port (i.e. a port in the | |
2550 | range 0 < portnr < 1024). | |
2551 | An administrator who wishes to reserve some of these | |
2552 | ports for other uses may adjust the range that the | |
2553 | kernel's sunrpc client considers to be privileged | |
2554 | using these two parameters to set the minimum and | |
2555 | maximum port values. | |
2556 | ||
42a7fc4a GB |
2557 | sunrpc.pool_mode= |
2558 | [NFS] | |
2559 | Control how the NFS server code allocates CPUs to | |
2560 | service thread pools. Depending on how many NICs | |
2561 | you have and where their interrupts are bound, this | |
2562 | option will affect which CPUs will do NFS serving. | |
2563 | Note: this parameter cannot be changed while the | |
2564 | NFS server is running. | |
2565 | ||
2566 | auto the server chooses an appropriate mode | |
2567 | automatically using heuristics | |
2568 | global a single global pool contains all CPUs | |
2569 | percpu one pool for each CPU | |
2570 | pernode one pool for each NUMA node (equivalent | |
2571 | to global on non-NUMA machines) | |
2572 | ||
cbf11071 TM |
2573 | sunrpc.tcp_slot_table_entries= |
2574 | sunrpc.udp_slot_table_entries= | |
2575 | [NFS,SUNRPC] | |
2576 | Sets the upper limit on the number of simultaneous | |
2577 | RPC calls that can be sent from the client to a | |
2578 | server. Increasing these values may allow you to | |
2579 | improve throughput, but will also increase the | |
2580 | amount of memory reserved for use by the client. | |
2581 | ||
1da177e4 | 2582 | swiotlb= [IA-64] Number of I/O TLB slabs |
a9913044 | 2583 | |
1da177e4 LT |
2584 | switches= [HW,M68k] |
2585 | ||
2586 | sym53c416= [HW,SCSI] | |
2587 | See header of drivers/scsi/sym53c416.c. | |
2588 | ||
5d6f647f IM |
2589 | sysrq_always_enabled |
2590 | [KNL] | |
2591 | Ignore sysrq setting - this boot parameter will | |
2592 | neutralize any effect of /proc/sys/kernel/sysrq. | |
2593 | Useful for debugging. | |
2594 | ||
1da177e4 LT |
2595 | t128= [HW,SCSI] |
2596 | See header of drivers/scsi/t128.c. | |
2597 | ||
2598 | tdfx= [HW,DRM] | |
2599 | ||
77437fd4 DB |
2600 | test_suspend= [SUSPEND] |
2601 | Specify "mem" (for Suspend-to-RAM) or "standby" (for | |
2602 | standby suspend) as the system sleep state to briefly | |
2603 | enter during system startup. The system is woken from | |
2604 | this state using a wakeup-capable RTC alarm. | |
2605 | ||
1da177e4 LT |
2606 | thash_entries= [KNL,NET] |
2607 | Set number of hash buckets for TCP connection | |
2608 | ||
f8707ec9 LB |
2609 | thermal.act= [HW,ACPI] |
2610 | -1: disable all active trip points in all thermal zones | |
2611 | <degrees C>: override all lowest active trip points | |
2612 | ||
c52a7419 LB |
2613 | thermal.crt= [HW,ACPI] |
2614 | -1: disable all critical trip points in all thermal zones | |
22a94d79 | 2615 | <degrees C>: override all critical trip points |
c52a7419 | 2616 | |
f5487145 LB |
2617 | thermal.nocrt= [HW,ACPI] |
2618 | Set to disable actions on ACPI thermal zone | |
2619 | critical and hot trip points. | |
2620 | ||
72b33ef8 LB |
2621 | thermal.off= [HW,ACPI] |
2622 | 1: disable ACPI thermal control | |
2623 | ||
a70cdc52 LB |
2624 | thermal.psv= [HW,ACPI] |
2625 | -1: disable all passive trip points | |
ada9cfdd RD |
2626 | <degrees C>: override all passive trip points to this |
2627 | value | |
a70cdc52 | 2628 | |
730ff34d LB |
2629 | thermal.tzp= [HW,ACPI] |
2630 | Specify global default ACPI thermal zone polling rate | |
2631 | <deci-seconds>: poll all this frequency | |
2632 | 0: no polling (default) | |
2633 | ||
1da177e4 LT |
2634 | tmscsim= [HW,SCSI] |
2635 | See comment before function dc390_setup() in | |
2636 | drivers/scsi/tmscsim.c. | |
2637 | ||
2b1a61f0 HC |
2638 | topology= [S390] |
2639 | Format: {off | on} | |
2640 | Specify if the kernel should make use of the cpu | |
2641 | topology informations if the hardware supports these. | |
2642 | The scheduler will make use of these informations and | |
2643 | e.g. base its process migration decisions on it. | |
2644 | Default is off. | |
2645 | ||
1da177e4 LT |
2646 | tp720= [HW,PS2] |
2647 | ||
225a9be2 RA |
2648 | tpm_suspend_pcr=[HW,TPM] |
2649 | Format: integer pcr id | |
2650 | Specify that at suspend time, the tpm driver | |
2651 | should extend the specified pcr with zeros, | |
2652 | as a workaround for some chips which fail to | |
2653 | flush the last written pcr on TPM_SaveState. | |
2654 | This will guarantee that all the other pcrs | |
2655 | are saved. | |
2656 | ||
9d612bef LZ |
2657 | trace_buf_size=nn[KMG] |
2658 | [FTRACE] will set tracing buffer size. | |
631595fb | 2659 | |
020e5f85 LZ |
2660 | trace_event=[event-list] |
2661 | [FTRACE] Set and start specified trace events in order | |
2662 | to facilitate early boot debugging. | |
2663 | See also Documentation/trace/events.txt | |
2664 | ||
1da177e4 | 2665 | trix= [HW,OSS] MediaTrix AudioTrix Pro |
a9913044 RD |
2666 | Format: |
2667 | <io>,<irq>,<dma>,<dma2>,<sb_io>,<sb_irq>,<sb_dma>,<mpu_io>,<mpu_irq> | |
2668 | ||
395628ef AK |
2669 | tsc= Disable clocksource-must-verify flag for TSC. |
2670 | Format: <string> | |
2671 | [x86] reliable: mark tsc clocksource as reliable, this | |
2672 | disables clocksource verification at runtime. | |
2673 | Used to enable high-resolution timer mode on older | |
2674 | hardware, and in virtualized environment. | |
2675 | ||
a9913044 RD |
2676 | turbografx.map[2|3]= [HW,JOY] |
2677 | TurboGraFX parallel port interface | |
2678 | Format: | |
2679 | <port#>,<js1>,<js2>,<js3>,<js4>,<js5>,<js6>,<js7> | |
1da177e4 LT |
2680 | See also Documentation/input/joystick-parport.txt |
2681 | ||
2682 | u14-34f= [HW,SCSI] UltraStor 14F/34F SCSI host adapter | |
2683 | See header of drivers/scsi/u14-34f.c. | |
2684 | ||
2685 | uart401= [HW,OSS] | |
2686 | Format: <io>,<irq> | |
2687 | ||
2688 | uart6850= [HW,OSS] | |
2689 | Format: <io>,<irq> | |
2690 | ||
f86dcc5a ED |
2691 | uhash_entries= [KNL,NET] |
2692 | Set number of hash buckets for UDP/UDP-Lite connections | |
2693 | ||
5f8364b7 AS |
2694 | uhci-hcd.ignore_oc= |
2695 | [USB] Ignore overcurrent events (default N). | |
2696 | Some badly-designed motherboards generate lots of | |
2697 | bogus events, for ports that aren't wired to | |
2698 | anything. Set this parameter to avoid log spamming. | |
2699 | Note that genuine overcurrent events won't be | |
2700 | reported either. | |
2701 | ||
e3a61b0a | 2702 | unknown_nmi_panic |
6cececfc | 2703 | [X86] |
e3a61b0a SA |
2704 | Set unknown_nmi_panic=1 early on boot. |
2705 | ||
b5e795f8 AS |
2706 | usbcore.autosuspend= |
2707 | [USB] The autosuspend time delay (in seconds) used | |
2708 | for newly-detected USB devices (default 2). This | |
2709 | is the time required before an idle device will be | |
2710 | autosuspended. Devices for which the delay is set | |
eaafbc3a | 2711 | to a negative value won't be autosuspended at all. |
b5e795f8 | 2712 | |
fd7c519d JK |
2713 | usbcore.usbfs_snoop= |
2714 | [USB] Set to log all usbfs traffic (default 0 = off). | |
2715 | ||
2716 | usbcore.blinkenlights= | |
2717 | [USB] Set to cycle leds on hubs (default 0 = off). | |
2718 | ||
2719 | usbcore.old_scheme_first= | |
2720 | [USB] Start with the old device initialization | |
2721 | scheme (default 0 = off). | |
2722 | ||
2723 | usbcore.use_both_schemes= | |
2724 | [USB] Try the other device initialization scheme | |
2725 | if the first one fails (default 1 = enabled). | |
2726 | ||
2727 | usbcore.initial_descriptor_timeout= | |
2728 | [USB] Specifies timeout for the initial 64-byte | |
2729 | USB_REQ_GET_DESCRIPTOR request in milliseconds | |
2730 | (default 5000 = 5.0 seconds). | |
2731 | ||
1da177e4 LT |
2732 | usbhid.mousepoll= |
2733 | [USBHID] The interval which mice are to be polled at. | |
a9913044 | 2734 | |
d4f373e5 AS |
2735 | usb-storage.delay_use= |
2736 | [UMS] The delay in seconds before a new device is | |
2737 | scanned for Logical Units (default 5). | |
2738 | ||
2739 | usb-storage.quirks= | |
2740 | [UMS] A list of quirks entries to supplement or | |
2741 | override the built-in unusual_devs list. List | |
2742 | entries are separated by commas. Each entry has | |
2743 | the form VID:PID:Flags where VID and PID are Vendor | |
2744 | and Product ID values (4-digit hex numbers) and | |
2745 | Flags is a set of characters, each corresponding | |
2746 | to a common usb-storage quirk flag as follows: | |
c838ea46 AS |
2747 | a = SANE_SENSE (collect more than 18 bytes |
2748 | of sense data); | |
a0bb1081 AS |
2749 | b = BAD_SENSE (don't collect more than 18 |
2750 | bytes of sense data); | |
d4f373e5 AS |
2751 | c = FIX_CAPACITY (decrease the reported |
2752 | device capacity by one sector); | |
c838ea46 AS |
2753 | h = CAPACITY_HEURISTICS (decrease the |
2754 | reported device capacity by one | |
2755 | sector if the number is odd); | |
d4f373e5 AS |
2756 | i = IGNORE_DEVICE (don't bind to this |
2757 | device); | |
2758 | l = NOT_LOCKABLE (don't try to lock and | |
2759 | unlock ejectable media); | |
2760 | m = MAX_SECTORS_64 (don't transfer more | |
2761 | than 64 sectors = 32 KB at a time); | |
c838ea46 AS |
2762 | o = CAPACITY_OK (accept the capacity |
2763 | reported by the device); | |
d4f373e5 AS |
2764 | r = IGNORE_RESIDUE (the device reports |
2765 | bogus residue values); | |
2766 | s = SINGLE_LUN (the device has only one | |
2767 | Logical Unit); | |
2768 | w = NO_WP_DETECT (don't test whether the | |
2769 | medium is write-protected). | |
2770 | Example: quirks=0419:aaf5:rl,0421:0433:rc | |
2771 | ||
14315592 IC |
2772 | userpte= |
2773 | [X86] Flags controlling user PTE allocations. | |
2774 | ||
2775 | nohigh = do not allocate PTE pages in | |
2776 | HIGHMEM regardless of setting | |
2777 | of CONFIG_HIGHPTE. | |
2778 | ||
6cececfc | 2779 | vdso= [X86,SH] |
1dbf527c | 2780 | vdso=2: enable compat VDSO (default with COMPAT_VDSO) |
e6e5494c IM |
2781 | vdso=1: enable VDSO (default) |
2782 | vdso=0: disable VDSO mapping | |
2783 | ||
6cececfc | 2784 | vdso32= [X86] |
af65d648 RM |
2785 | vdso32=2: enable compat VDSO (default with COMPAT_VDSO) |
2786 | vdso32=1: enable 32-bit VDSO (default) | |
2787 | vdso32=0: disable 32-bit VDSO mapping | |
2788 | ||
d080d397 YI |
2789 | vector= [IA-64,SMP] |
2790 | vector=percpu: enable percpu vector domain | |
2791 | ||
1da177e4 LT |
2792 | video= [FB] Frame buffer configuration |
2793 | See Documentation/fb/modedb.txt. | |
2794 | ||
cd4f0ef7 | 2795 | vga= [BOOT,X86-32] Select a particular video mode |
954a8b81 | 2796 | See Documentation/x86/boot.txt and |
a9913044 | 2797 | Documentation/svga.txt. |
1da177e4 LT |
2798 | Use vga=ask for menu. |
2799 | This is actually a boot loader parameter; the value is | |
2800 | passed to the kernel using a special protocol. | |
2801 | ||
a9913044 | 2802 | vmalloc=nn[KMG] [KNL,BOOT] Forces the vmalloc area to have an exact |
1da177e4 LT |
2803 | size of <nn>. This can be used to increase the |
2804 | minimum size (128MB on x86). It can also be used to | |
2805 | decrease the size and leave more room for directly | |
2806 | mapped kernel RAM. | |
2807 | ||
585c3047 PO |
2808 | vmhalt= [KNL,S390] Perform z/VM CP command after system halt. |
2809 | Format: <command> | |
1da177e4 | 2810 | |
585c3047 PO |
2811 | vmpanic= [KNL,S390] Perform z/VM CP command after kernel panic. |
2812 | Format: <command> | |
2813 | ||
2814 | vmpoff= [KNL,S390] Perform z/VM CP command after power off. | |
2815 | Format: <command> | |
a9913044 | 2816 | |
9ea9a886 CL |
2817 | vt.cur_default= [VT] Default cursor shape. |
2818 | Format: 0xCCBBAA, where AA, BB, and CC are the same as | |
2819 | the parameters of the <Esc>[?A;B;Cc escape sequence; | |
2820 | see VGA-softcursor.txt. Default: 2 = underline. | |
2821 | ||
0cb55ad2 RD |
2822 | vt.default_blu= [VT] |
2823 | Format: <blue0>,<blue1>,<blue2>,...,<blue15> | |
2824 | Change the default blue palette of the console. | |
2825 | This is a 16-member array composed of values | |
2826 | ranging from 0-255. | |
2827 | ||
2828 | vt.default_grn= [VT] | |
2829 | Format: <green0>,<green1>,<green2>,...,<green15> | |
2830 | Change the default green palette of the console. | |
2831 | This is a 16-member array composed of values | |
2832 | ranging from 0-255. | |
2833 | ||
2834 | vt.default_red= [VT] | |
2835 | Format: <red0>,<red1>,<red2>,...,<red15> | |
2836 | Change the default red palette of the console. | |
2837 | This is a 16-member array composed of values | |
2838 | ranging from 0-255. | |
2839 | ||
2840 | vt.default_utf8= | |
2841 | [VT] | |
2842 | Format=<0|1> | |
2843 | Set system-wide default UTF-8 mode for all tty's. | |
2844 | Default is 1, i.e. UTF-8 mode is enabled for all | |
2845 | newly opened terminals. | |
2846 | ||
f6c06b68 MG |
2847 | vt.global_cursor_default= |
2848 | [VT] | |
2849 | Format=<-1|0|1> | |
2850 | Set system-wide default for whether a cursor | |
2851 | is shown on new VTs. Default is -1, | |
2852 | i.e. cursors will be created by default unless | |
2853 | overridden by individual drivers. 0 will hide | |
2854 | cursors, 1 will display them. | |
2855 | ||
1da177e4 LT |
2856 | waveartist= [HW,OSS] |
2857 | Format: <io>,<irq>,<dma>,<dma2> | |
a9913044 | 2858 | |
1da177e4 LT |
2859 | wd33c93= [HW,SCSI] |
2860 | See header of drivers/scsi/wd33c93.c. | |
2861 | ||
2862 | wd7000= [HW,SCSI] | |
2863 | See header of drivers/scsi/wd7000.c. | |
2864 | ||
4724ba57 RD |
2865 | watchdog timers [HW,WDT] For information on watchdog timers, |
2866 | see Documentation/watchdog/watchdog-parameters.txt | |
2867 | or other driver-specific files in the | |
2868 | Documentation/watchdog/ directory. | |
1da177e4 | 2869 | |
0cb55ad2 RD |
2870 | x2apic_phys [X86-64,APIC] Use x2apic physical mode instead of |
2871 | default x2apic cluster mode on platforms | |
2872 | supporting x2apic. | |
2873 | ||
bb24c471 JP |
2874 | x86_mrst_timer= [X86-32,APBT] |
2875 | Choose timer option for x86 Moorestown MID platform. | |
2876 | Two valid options are apbt timer only and lapic timer | |
2877 | plus one apbt timer for broadcast timer. | |
2878 | x86_mrst_timer=apbt_only | lapic_and_apbt | |
2879 | ||
1da177e4 LT |
2880 | xd= [HW,XT] Original XT pre-IDE (RLL encoded) disks. |
2881 | xd_geo= See header of drivers/block/xd.c. | |
2882 | ||
c1c5413a SS |
2883 | xen_emul_unplug= [HW,X86,XEN] |
2884 | Unplug Xen emulated devices | |
2885 | Format: [unplug0,][unplug1] | |
2886 | ide-disks -- unplug primary master IDE devices | |
2887 | aux-ide-disks -- unplug non-primary-master IDE devices | |
2888 | nics -- unplug network devices | |
2889 | all -- unplug all emulated devices (NICs and IDE disks) | |
2890 | ignore -- continue loading the Xen platform PCI driver even | |
2891 | if the version check failed | |
2892 | ||
1da177e4 | 2893 | xirc2ps_cs= [NET,PCMCIA] |
a9913044 RD |
2894 | Format: |
2895 | <irq>,<irq_mask>,<io>,<full_duplex>,<do_sound>,<lockup_hack>[,<irq2>[,<irq3>[,<irq4>]]] | |
1da177e4 | 2896 | |
a9913044 | 2897 | ______________________________________________________________________ |
1da177e4 LT |
2898 | |
2899 | TODO: | |
2900 | ||
2901 | Add documentation for ALSA options. | |
2902 | Add more DRM drivers. |