Commit | Line | Data |
---|---|---|
0ee9d71f | 1 | Kernel Parameters |
1da177e4 LT |
2 | ~~~~~~~~~~~~~~~~~ |
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 | ||
a901ebb9 SR |
20 | This document may not be entirely up to date and comprehensive. The command |
21 | "modinfo -p ${modulename}" shows a current list of all parameters of a loadable | |
22 | module. Loadable modules, after being loaded into the running kernel, also | |
23 | reveal their parameters in /sys/module/${modulename}/parameters/. Some of these | |
24 | parameters may be changed at runtime by the command | |
25 | "echo -n ${value} > /sys/module/${modulename}/parameters/${parm}". | |
26 | ||
6585fa8a SR |
27 | The parameters listed below are only valid if certain kernel build options were |
28 | enabled and if respective hardware is present. The text in square brackets at | |
29 | the beginning of each description states the restrictions within which a | |
30 | parameter is applicable: | |
1da177e4 LT |
31 | |
32 | ACPI ACPI support is enabled. | |
33 | ALSA ALSA sound support is enabled. | |
34 | APIC APIC support is enabled. | |
35 | APM Advanced Power Management support is enabled. | |
36 | AX25 Appropriate AX.25 support is enabled. | |
37 | CD Appropriate CD support is enabled. | |
a9913044 | 38 | DRM Direct Rendering Management support is enabled. |
1da177e4 LT |
39 | EDD BIOS Enhanced Disk Drive Services (EDD) is enabled |
40 | EFI EFI Partitioning (GPT) is enabled | |
41 | EIDE EIDE/ATAPI support is enabled. | |
42 | FB The frame buffer device is enabled. | |
43 | HW Appropriate hardware is enabled. | |
44 | IA-32 IA-32 aka i386 architecture is enabled. | |
45 | IA-64 IA-64 architecture is enabled. | |
46 | IOSCHED More than one I/O scheduler is enabled. | |
41e2e8be | 47 | IP_PNP IP DHCP, BOOTP, or RARP is enabled. |
1da177e4 LT |
48 | ISAPNP ISA PnP code is enabled. |
49 | ISDN Appropriate ISDN support is enabled. | |
50 | JOY Appropriate joystick support is enabled. | |
11ef697b | 51 | LIBATA Libata driver is enabled |
1da177e4 LT |
52 | LP Printer support is enabled. |
53 | LOOP Loopback device support is enabled. | |
54 | M68k M68k architecture is enabled. | |
55 | These options have more detailed description inside of | |
56 | Documentation/m68k/kernel-options.txt. | |
57 | MCA MCA bus support is enabled. | |
58 | MDA MDA console support is enabled. | |
59 | MOUSE Appropriate mouse support is enabled. | |
309e57df | 60 | MSI Message Signaled Interrupts (PCI). |
1da177e4 LT |
61 | MTD MTD support is enabled. |
62 | NET Appropriate network support is enabled. | |
63 | NUMA NUMA support is enabled. | |
734efb46 | 64 | GENERIC_TIME The generic timeofday code is enabled. |
1da177e4 LT |
65 | NFS Appropriate NFS support is enabled. |
66 | OSS OSS sound support is enabled. | |
67 | PARIDE The ParIDE subsystem is enabled. | |
68 | PARISC The PA-RISC architecture is enabled. | |
69 | PCI PCI bus support is enabled. | |
70 | PCMCIA The PCMCIA subsystem is enabled. | |
71 | PNP Plug & Play support is enabled. | |
72 | PPC PowerPC architecture is enabled. | |
73 | PPT Parallel port support is enabled. | |
74 | PS2 Appropriate PS/2 support is enabled. | |
75 | RAM RAM disk support is enabled. | |
76 | S390 S390 architecture is enabled. | |
77 | SCSI Appropriate SCSI support is enabled. | |
78 | A lot of drivers has their options described inside of | |
79 | Documentation/scsi/. | |
80 | SELINUX SELinux support is enabled. | |
81 | SERIAL Serial support is enabled. | |
e523d93c | 82 | SH SuperH architecture is enabled. |
1da177e4 LT |
83 | SMP The kernel is an SMP kernel. |
84 | SPARC Sparc architecture is enabled. | |
a9913044 | 85 | SWSUSP Software suspend is enabled. |
1da177e4 LT |
86 | TS Appropriate touchscreen support is enabled. |
87 | USB USB support is enabled. | |
88 | USBHID USB Human Interface Device support is enabled. | |
89 | V4L Video For Linux support is enabled. | |
90 | VGA The VGA console has been enabled. | |
91 | VT Virtual terminal support is enabled. | |
92 | WDT Watchdog support is enabled. | |
93 | XT IBM PC/XT MFM hard disk support is enabled. | |
94 | X86-64 X86-64 architecture is enabled. | |
95 | More X86-64 boot options can be found in | |
96 | Documentation/x86_64/boot-options.txt . | |
97 | ||
98 | In addition, the following text indicates that the option: | |
99 | ||
100 | BUGS= Relates to possible processor bugs on the said processor. | |
101 | KNL Is a kernel start-up parameter. | |
102 | BOOT Is a boot loader parameter. | |
103 | ||
104 | Parameters denoted with BOOT are actually interpreted by the boot | |
105 | loader, and have no meaning to the kernel directly. | |
106 | Do not modify the syntax of boot loader parameters without extreme | |
107 | need or coordination with <Documentation/i386/boot.txt>. | |
108 | ||
5558870b KW |
109 | There are also arch-specific kernel-parameters not documented here. |
110 | See for example <Documentation/x86_64/boot-options.txt>. | |
111 | ||
1da177e4 LT |
112 | Note that ALL kernel parameters listed below are CASE SENSITIVE, and that |
113 | a trailing = on the name of any parameter states that that parameter will | |
114 | be entered as an environment variable, whereas its absence indicates that | |
115 | it will appear as a kernel argument readable via /proc/cmdline by programs | |
116 | running once the system is up. | |
117 | ||
9c4751fd | 118 | The number of kernel parameters is not limited, but the length of the |
119 | complete command line (parameters including spaces etc.) is limited to | |
120 | a fixed number of characters. This limit depends on the architecture | |
121 | and is between 256 and 4096 characters. It is defined in the file | |
122 | ./include/asm/setup.h as COMMAND_LINE_SIZE. | |
123 | ||
124 | ||
1da177e4 LT |
125 | 53c7xx= [HW,SCSI] Amiga SCSI controllers |
126 | See header of drivers/scsi/53c7xx.c. | |
127 | See also Documentation/scsi/ncr53c7xx.txt. | |
128 | ||
03d926f8 BW |
129 | acpi= [HW,ACPI,X86-64,i386] |
130 | Advanced Configuration and Power Interface | |
a9913044 | 131 | Format: { force | off | ht | strict | noirq } |
1da177e4 LT |
132 | force -- enable ACPI if default was off |
133 | off -- disable ACPI if default was on | |
134 | noirq -- do not use ACPI for IRQ routing | |
135 | ht -- run only enough ACPI to enable Hyper Threading | |
a9913044 | 136 | strict -- Be less tolerant of platforms that are not |
1da177e4 LT |
137 | strictly ACPI specification compliant. |
138 | ||
139 | See also Documentation/pm.txt, pci=noacpi | |
140 | ||
a1fdcc0d LB |
141 | acpi_apic_instance= [ACPI, IOAPIC] |
142 | Format: <int> | |
143 | 2: use 2nd APIC table, if available | |
144 | 1,0: use 1st APIC table | |
09fe5835 | 145 | default: 2 |
a1fdcc0d | 146 | |
1da177e4 LT |
147 | acpi_sleep= [HW,ACPI] Sleep options |
148 | Format: { s3_bios, s3_mode } | |
149 | See Documentation/power/video.txt | |
a9913044 | 150 | |
1da177e4 | 151 | acpi_sci= [HW,ACPI] ACPI System Control Interrupt trigger mode |
a9913044 | 152 | Format: { level | edge | high | low } |
1da177e4 | 153 | |
a9913044 RD |
154 | acpi_irq_balance [HW,ACPI] |
155 | ACPI will balance active IRQs | |
156 | default in APIC mode | |
1da177e4 | 157 | |
a9913044 RD |
158 | acpi_irq_nobalance [HW,ACPI] |
159 | ACPI will not move active IRQs (default) | |
160 | default in PIC mode | |
1da177e4 | 161 | |
a9913044 RD |
162 | acpi_irq_pci= [HW,ACPI] If irq_balance, clear listed IRQs for |
163 | use by PCI | |
1da177e4 LT |
164 | Format: <irq>,<irq>... |
165 | ||
a9913044 | 166 | acpi_irq_isa= [HW,ACPI] If irq_balance, mark listed IRQs used by ISA |
1da177e4 LT |
167 | Format: <irq>,<irq>... |
168 | ||
a1f9e65e LB |
169 | acpi_os_name= [HW,ACPI] Tell ACPI BIOS the name of the OS |
170 | Format: To spoof as Windows 98: ="Microsoft Windows" | |
171 | ||
1da177e4 LT |
172 | acpi_osi= [HW,ACPI] empty param disables _OSI |
173 | ||
174 | acpi_serialize [HW,ACPI] force serialization of AML methods | |
175 | ||
176 | acpi_skip_timer_override [HW,ACPI] | |
177 | Recognize and ignore IRQ0/pin2 Interrupt Override. | |
178 | For broken nForce2 BIOS resulting in XT-PIC timer. | |
fa18f477 AK |
179 | acpi_use_timer_override [HW,ACPI} |
180 | Use timer override. For some broken Nvidia NF5 boards | |
181 | that require a timer override, but don't have | |
182 | HPET | |
1da177e4 LT |
183 | |
184 | acpi_dbg_layer= [HW,ACPI] | |
185 | Format: <int> | |
a9913044 | 186 | Each bit of the <int> indicates an ACPI debug layer, |
1da177e4 LT |
187 | 1: enable, 0: disable. It is useful for boot time |
188 | debugging. After system has booted up, it can be set | |
189 | via /proc/acpi/debug_layer. | |
190 | ||
191 | acpi_dbg_level= [HW,ACPI] | |
192 | Format: <int> | |
a9913044 | 193 | Each bit of the <int> indicates an ACPI debug level, |
1da177e4 LT |
194 | 1: enable, 0: disable. It is useful for boot time |
195 | debugging. After system has booted up, it can be set | |
196 | via /proc/acpi/debug_level. | |
197 | ||
198 | acpi_fake_ecdt [HW,ACPI] Workaround failure due to BIOS lacking ECDT | |
199 | ||
30e332f3 LY |
200 | acpi_generic_hotkey [HW,ACPI] |
201 | Allow consolidated generic hotkey driver to | |
a9913044 | 202 | override platform specific driver. |
30e332f3 LY |
203 | See also Documentation/acpi-hotkey.txt. |
204 | ||
5d0cf410 | 205 | acpi_pm_good [IA-32,X86-64] |
206 | Override the pmtimer bug detection: force the kernel | |
207 | to assume that this machine's pmtimer latches its value | |
208 | and always returns good values. | |
209 | ||
66759a01 CE |
210 | enable_timer_pin_1 [i386,x86-64] |
211 | Enable PIN 1 of APIC timer | |
a9913044 RD |
212 | Can be useful to work around chipset bugs |
213 | (in particular on some ATI chipsets). | |
66759a01 CE |
214 | The kernel tries to set a reasonable default. |
215 | ||
216 | disable_timer_pin_1 [i386,x86-64] | |
217 | Disable PIN 1 of APIC timer | |
218 | Can be useful to work around chipset bugs. | |
219 | ||
1da177e4 LT |
220 | ad1816= [HW,OSS] |
221 | Format: <io>,<irq>,<dma>,<dma2> | |
222 | See also Documentation/sound/oss/AD1816. | |
223 | ||
224 | ad1848= [HW,OSS] | |
225 | Format: <io>,<irq>,<dma>,<dma2>,<type> | |
226 | ||
227 | adlib= [HW,OSS] | |
228 | Format: <io> | |
a9913044 | 229 | |
1da177e4 LT |
230 | advansys= [HW,SCSI] |
231 | See header of drivers/scsi/advansys.c. | |
232 | ||
233 | advwdt= [HW,WDT] Advantech WDT | |
234 | Format: <iostart>,<iostop> | |
235 | ||
236 | aedsp16= [HW,OSS] Audio Excel DSP 16 | |
237 | Format: <io>,<irq>,<dma>,<mss_io>,<mpu_io>,<mpu_irq> | |
238 | See also header of sound/oss/aedsp16.c. | |
a9913044 | 239 | |
1da177e4 LT |
240 | aha152x= [HW,SCSI] |
241 | See Documentation/scsi/aha152x.txt. | |
242 | ||
243 | aha1542= [HW,SCSI] | |
244 | Format: <portbase>[,<buson>,<busoff>[,<dmaspeed>]] | |
245 | ||
246 | aic7xxx= [HW,SCSI] | |
247 | See Documentation/scsi/aic7xxx.txt. | |
248 | ||
249 | aic79xx= [HW,SCSI] | |
250 | See Documentation/scsi/aic79xx.txt. | |
251 | ||
1da177e4 LT |
252 | amijoy.map= [HW,JOY] Amiga joystick support |
253 | Map of devices attached to JOY0DAT and JOY1DAT | |
254 | Format: <a>,<b> | |
255 | See also Documentation/kernel/input/joystick.txt | |
256 | ||
257 | analog.map= [HW,JOY] Analog joystick and gamepad support | |
258 | Specifies type or capabilities of an analog joystick | |
259 | connected to one of 16 gameports | |
260 | Format: <type1>,<type2>,..<type16> | |
261 | ||
a9913044 RD |
262 | apc= [HW,SPARC] |
263 | Power management functions (SPARCstation-4/5 + deriv.) | |
1da177e4 LT |
264 | Format: noidle |
265 | Disable APC CPU standby support. SPARCstation-Fox does | |
266 | not play well with APC CPU idle - disable it if you have | |
267 | APC and your system crashes randomly. | |
268 | ||
a9913044 | 269 | apic= [APIC,i386] Change the output verbosity whilst booting |
1da177e4 LT |
270 | Format: { quiet (default) | verbose | debug } |
271 | Change the amount of debugging information output | |
272 | when initialising the APIC and IO-APIC components. | |
a9913044 | 273 | |
1da177e4 LT |
274 | apm= [APM] Advanced Power Management |
275 | See header of arch/i386/kernel/apm.c. | |
276 | ||
277 | applicom= [HW] | |
278 | Format: <mem>,<irq> | |
a9913044 | 279 | |
1da177e4 LT |
280 | arcrimi= [HW,NET] ARCnet - "RIM I" (entirely mem-mapped) cards |
281 | Format: <io>,<irq>,<nodeID> | |
282 | ||
283 | ataflop= [HW,M68k] | |
284 | ||
285 | atarimouse= [HW,MOUSE] Atari Mouse | |
286 | ||
287 | atascsi= [HW,SCSI] Atari SCSI | |
288 | ||
289 | atkbd.extra= [HW] Enable extra LEDs and keys on IBM RapidAccess, | |
290 | EzKey and similar keyboards | |
291 | ||
292 | atkbd.reset= [HW] Reset keyboard during initialization | |
293 | ||
a9913044 RD |
294 | atkbd.set= [HW] Select keyboard code set |
295 | Format: <int> (2 = AT (default), 3 = PS/2) | |
1da177e4 LT |
296 | |
297 | atkbd.scroll= [HW] Enable scroll wheel on MS Office and similar | |
298 | keyboards | |
299 | ||
300 | atkbd.softraw= [HW] Choose between synthetic and real raw mode | |
301 | Format: <bool> (0 = real, 1 = synthetic (default)) | |
a9913044 RD |
302 | |
303 | atkbd.softrepeat= [HW] | |
304 | Use software keyboard repeat | |
1da177e4 LT |
305 | |
306 | autotest [IA64] | |
307 | ||
1da177e4 LT |
308 | aztcd= [HW,CD] Aztech CD268 CDROM driver |
309 | Format: <io>,0x79 (?) | |
310 | ||
311 | baycom_epp= [HW,AX25] | |
312 | Format: <io>,<mode> | |
a9913044 | 313 | |
1da177e4 LT |
314 | baycom_par= [HW,AX25] BayCom Parallel Port AX.25 Modem |
315 | Format: <io>,<mode> | |
316 | See header of drivers/net/hamradio/baycom_par.c. | |
317 | ||
a9913044 RD |
318 | baycom_ser_fdx= [HW,AX25] |
319 | BayCom Serial Port AX.25 Modem (Full Duplex Mode) | |
1da177e4 LT |
320 | Format: <io>,<irq>,<mode>[,<baud>] |
321 | See header of drivers/net/hamradio/baycom_ser_fdx.c. | |
322 | ||
a9913044 RD |
323 | baycom_ser_hdx= [HW,AX25] |
324 | BayCom Serial Port AX.25 Modem (Half Duplex Mode) | |
1da177e4 LT |
325 | Format: <io>,<irq>,<mode> |
326 | See header of drivers/net/hamradio/baycom_ser_hdx.c. | |
327 | ||
328 | blkmtd_device= [HW,MTD] | |
329 | blkmtd_erasesz= | |
330 | blkmtd_ro= | |
331 | blkmtd_bs= | |
332 | blkmtd_count= | |
333 | ||
334 | bttv.card= [HW,V4L] bttv (bt848 + bt878 based grabber cards) | |
a9913044 RD |
335 | bttv.radio= Most important insmod options are available as |
336 | kernel args too. | |
1da177e4 LT |
337 | bttv.pll= See Documentation/video4linux/bttv/Insmod-options |
338 | bttv.tuner= and Documentation/video4linux/bttv/CARDLIST | |
339 | ||
340 | BusLogic= [HW,SCSI] | |
341 | See drivers/scsi/BusLogic.c, comment before function | |
342 | BusLogic_ParseDriverOptions(). | |
343 | ||
344 | c101= [NET] Moxa C101 synchronous serial card | |
345 | ||
346 | cachesize= [BUGS=IA-32] Override level 2 CPU cache size detection. | |
347 | Sometimes CPU hardware bugs make them report the cache | |
348 | size incorrectly. The kernel will attempt work arounds | |
349 | to fix known problems, but for some CPUs it is not | |
350 | possible to determine what the correct size should be. | |
351 | This option provides an override for these situations. | |
352 | ||
353 | cdu31a= [HW,CD] | |
354 | Format: <io>,<irq>[,PAS] | |
355 | See header of drivers/cdrom/cdu31a.c. | |
356 | ||
357 | chandev= [HW,NET] Generic channel device initialisation | |
358 | ||
359 | checkreqprot [SELINUX] Set initial checkreqprot flag value. | |
360 | Format: { "0" | "1" } | |
361 | See security/selinux/Kconfig help text. | |
a9913044 RD |
362 | 0 -- check protection applied by kernel (includes |
363 | any implied execute protection). | |
1da177e4 LT |
364 | 1 -- check protection requested by application. |
365 | Default value is set via a kernel config option. | |
a9913044 RD |
366 | Value can be changed at runtime via |
367 | /selinux/checkreqprot. | |
368 | ||
734efb46 | 369 | clock= [BUGS=IA-32, HW] gettimeofday clocksource override. |
370 | [Deprecated] | |
3f6dee9b | 371 | Forces specified clocksource (if available) to be used |
734efb46 | 372 | when calculating gettimeofday(). If specified |
3f6dee9b | 373 | clocksource is not available, it defaults to PIT. |
1da177e4 LT |
374 | Format: { pit | tsc | cyclone | pmtmr } |
375 | ||
86c41837 CE |
376 | code_bytes [IA32] How many bytes of object code to print in an |
377 | oops report. | |
378 | Range: 0 - 8192 | |
379 | Default: 64 | |
380 | ||
f9262c12 AK |
381 | disable_8254_timer |
382 | enable_8254_timer | |
383 | [IA32/X86_64] Disable/Enable interrupt 0 timer routing | |
384 | over the 8254 in addition to over the IO-APIC. The | |
385 | kernel tries to set a sensible default. | |
386 | ||
1da177e4 LT |
387 | hpet= [IA-32,HPET] option to disable HPET and use PIT. |
388 | Format: disable | |
389 | ||
390 | cm206= [HW,CD] | |
391 | Format: { auto | [<io>,][<irq>] } | |
392 | ||
393 | com20020= [HW,NET] ARCnet - COM20020 chipset | |
a9913044 RD |
394 | Format: |
395 | <io>[,<irq>[,<nodeID>[,<backplane>[,<ckp>[,<timeout>]]]]] | |
1da177e4 LT |
396 | |
397 | com90io= [HW,NET] ARCnet - COM90xx chipset (IO-mapped buffers) | |
398 | Format: <io>[,<irq>] | |
399 | ||
a9913044 RD |
400 | com90xx= [HW,NET] |
401 | ARCnet - COM90xx chipset (memory-mapped buffers) | |
1da177e4 LT |
402 | Format: <io>[,<irq>[,<memstart>]] |
403 | ||
404 | condev= [HW,S390] console device | |
405 | conmode= | |
a9913044 | 406 | |
1da177e4 LT |
407 | console= [KNL] Output console device and options. |
408 | ||
409 | tty<n> Use the virtual console device <n>. | |
410 | ||
411 | ttyS<n>[,options] | |
f1a1c2dc | 412 | ttyUSB0[,options] |
1da177e4 | 413 | Use the specified serial port. The options are of |
f1a1c2dc RD |
414 | the form "bbbbpnf", where "bbbb" is the baud rate, |
415 | "p" is parity ("n", "o", or "e"), "n" is number of | |
416 | bits, and "f" is flow control ("r" for RTS or | |
417 | omit it). Default is "9600n8". | |
418 | ||
419 | See Documentation/serial-console.txt for more | |
420 | information. See | |
421 | Documentation/networking/netconsole.txt for an | |
422 | alternative. | |
1da177e4 LT |
423 | |
424 | uart,io,<addr>[,options] | |
425 | uart,mmio,<addr>[,options] | |
426 | Start an early, polled-mode console on the 8250/16550 | |
427 | UART at the specified I/O port or MMIO address, | |
428 | switching to the matching ttyS device later. The | |
429 | options are the same as for ttyS, above. | |
430 | ||
431 | cpcihp_generic= [HW,PCI] Generic port I/O CompactPCI driver | |
a9913044 RD |
432 | Format: |
433 | <first_slot>,<last_slot>,<port>,<enum_bit>[,<debug>] | |
1da177e4 LT |
434 | |
435 | cpia_pp= [HW,PPT] | |
436 | Format: { parport<nr> | auto | none } | |
437 | ||
dc009d92 EB |
438 | crashkernel=nn[KMG]@ss[KMG] |
439 | [KNL] Reserve a chunk of physical memory to | |
440 | hold a kernel to switch to with kexec on panic. | |
441 | ||
1da177e4 LT |
442 | cs4232= [HW,OSS] |
443 | Format: <io>,<irq>,<dma>,<dma2>,<mpuio>,<mpuirq> | |
444 | ||
445 | cs89x0_dma= [HW,NET] | |
446 | Format: <dma> | |
447 | ||
448 | cs89x0_media= [HW,NET] | |
449 | Format: { rj45 | aui | bnc } | |
a9913044 | 450 | |
1da177e4 | 451 | cyclades= [HW,SERIAL] Cyclades multi-serial port adapter. |
a9913044 RD |
452 | |
453 | dasd= [HW,NET] | |
1da177e4 LT |
454 | See header of drivers/s390/block/dasd_devmap.c. |
455 | ||
456 | db9.dev[2|3]= [HW,JOY] Multisystem joystick support via parallel port | |
457 | (one device per port) | |
458 | Format: <port#>,<type> | |
459 | See also Documentation/input/joystick-parport.txt | |
460 | ||
461 | debug [KNL] Enable kernel debugging (events log level). | |
462 | ||
cae2ed9a IM |
463 | debug_locks_verbose= |
464 | [KNL] verbose self-tests | |
465 | Format=<0|1> | |
466 | Print debugging info while doing the locking API | |
467 | self-tests. | |
468 | We default to 0 (no extra messages), setting it to | |
469 | 1 will print _a lot_ more information - normally | |
470 | only useful to kernel developers. | |
471 | ||
1da177e4 LT |
472 | decnet= [HW,NET] |
473 | Format: <area>[,<node>] | |
474 | See also Documentation/networking/decnet.txt. | |
475 | ||
1da177e4 LT |
476 | dhash_entries= [KNL] |
477 | Set number of hash buckets for dentry cache. | |
a9913044 | 478 | |
1da177e4 LT |
479 | digi= [HW,SERIAL] |
480 | IO parameters + enable/disable command. | |
481 | ||
482 | digiepca= [HW,SERIAL] | |
483 | See drivers/char/README.epca and | |
484 | Documentation/digiepca.txt. | |
485 | ||
486 | dmascc= [HW,AX25,SERIAL] AX.25 Z80SCC driver with DMA | |
487 | support available. | |
488 | Format: <io_dev0>[,<io_dev1>[,..<io_dev32>]] | |
489 | ||
490 | dmasound= [HW,OSS] Sound subsystem buffers | |
491 | ||
492 | dscc4.setup= [NET] | |
493 | ||
494 | dtc3181e= [HW,SCSI] | |
495 | ||
e523d93c | 496 | earlyprintk= [IA-32,X86-64,SH] |
1da177e4 LT |
497 | earlyprintk=vga |
498 | earlyprintk=serial[,ttySn[,baudrate]] | |
499 | ||
a9913044 | 500 | Append ",keep" to not disable it when the real console |
1da177e4 LT |
501 | takes over. |
502 | ||
503 | Only vga or serial at a time, not both. | |
504 | ||
505 | Currently only ttyS0 and ttyS1 are supported. | |
506 | ||
507 | Interaction with the standard serial driver is not | |
508 | very good. | |
509 | ||
510 | The VGA output is eventually overwritten by the real | |
511 | console. | |
512 | ||
513 | eata= [HW,SCSI] | |
514 | ||
53f11d4f LB |
515 | ec_intr= [HW,ACPI] ACPI Embedded Controller interrupt mode |
516 | Format: <int> | |
517 | 0: polling mode | |
518 | non-0: interrupt mode (default) | |
519 | ||
1da177e4 LT |
520 | eda= [HW,PS2] |
521 | ||
522 | edb= [HW,PS2] | |
523 | ||
524 | edd= [EDD] | |
525 | Format: {"of[f]" | "sk[ipmbr]"} | |
526 | See comment in arch/i386/boot/edd.S | |
527 | ||
a9913044 | 528 | eicon= [HW,ISDN] |
1da177e4 LT |
529 | Format: <id>,<membase>,<irq> |
530 | ||
531 | eisa_irq_edge= [PARISC,HW] | |
532 | See header of drivers/parisc/eisa.c. | |
533 | ||
534 | elanfreq= [IA-32] | |
535 | See comment before function elanfreq_setup() in | |
536 | arch/i386/kernel/cpu/cpufreq/elanfreq.c. | |
537 | ||
538 | elevator= [IOSCHED] | |
16ab3adf | 539 | Format: {"anticipatory" | "cfq" | "deadline" | "noop"} |
a9913044 RD |
540 | See Documentation/block/as-iosched.txt and |
541 | Documentation/block/deadline-iosched.txt for details. | |
542 | ||
aac04b32 | 543 | elfcorehdr= [IA-32, X86_64] |
a9913044 | 544 | Specifies physical address of start of kernel core |
aac04b32 VG |
545 | image elf header. Generally kexec loader will |
546 | pass this option to capture kernel. | |
547 | See Documentation/kdump/kdump.txt for details. | |
1da177e4 LT |
548 | |
549 | enforcing [SELINUX] Set initial enforcing status. | |
550 | Format: {"0" | "1"} | |
551 | See security/selinux/Kconfig help text. | |
552 | 0 -- permissive (log only, no denials). | |
553 | 1 -- enforcing (deny and log). | |
554 | Default value is 0. | |
555 | Value can be changed at runtime via /selinux/enforce. | |
556 | ||
1da177e4 LT |
557 | es1371= [HW,OSS] |
558 | Format: <spdif>,[<nomix>,[<amplifier>]] | |
559 | See also header of sound/oss/es1371.c. | |
a9913044 | 560 | |
1da177e4 LT |
561 | ether= [HW,NET] Ethernet cards parameters |
562 | This option is obsoleted by the "netdev=" option, which | |
563 | has equivalent usage. See its documentation for details. | |
564 | ||
565 | eurwdt= [HW,WDT] Eurotech CPU-1220/1410 onboard watchdog. | |
566 | Format: <io>[,<irq>] | |
567 | ||
de1ba09b AM |
568 | failslab= |
569 | fail_page_alloc= | |
570 | fail_make_request=[KNL] | |
571 | General fault injection mechanism. | |
572 | Format: <interval>,<probability>,<space>,<times> | |
573 | See also /Documentation/fault-injection/. | |
574 | ||
1da177e4 LT |
575 | fd_mcs= [HW,SCSI] |
576 | See header of drivers/scsi/fd_mcs.c. | |
577 | ||
578 | fdomain= [HW,SCSI] | |
579 | See header of drivers/scsi/fdomain.c. | |
580 | ||
581 | floppy= [HW] | |
582 | See Documentation/floppy.txt. | |
583 | ||
1da177e4 LT |
584 | gamecon.map[2|3]= |
585 | [HW,JOY] Multisystem joystick and NES/SNES/PSX pad | |
586 | support via parallel port (up to 5 devices per port) | |
587 | Format: <port#>,<pad1>,<pad2>,<pad3>,<pad4>,<pad5> | |
588 | See also Documentation/input/joystick-parport.txt | |
589 | ||
590 | gamma= [HW,DRM] | |
591 | ||
592 | gdth= [HW,SCSI] | |
593 | See header of drivers/scsi/gdth.c. | |
594 | ||
595 | gpt [EFI] Forces disk with valid GPT signature but | |
596 | invalid Protective MBR to be treated as GPT. | |
597 | ||
598 | gscd= [HW,CD] | |
599 | Format: <io> | |
600 | ||
1da177e4 LT |
601 | gvp11= [HW,SCSI] |
602 | ||
603 | hashdist= [KNL,NUMA] Large hashes allocated during boot | |
604 | are distributed across NUMA nodes. Defaults on | |
605 | for IA-64, off otherwise. | |
a9913044 | 606 | Format: 0 | 1 (for off | on) |
1da177e4 LT |
607 | |
608 | hcl= [IA-64] SGI's Hardware Graph compatibility layer | |
609 | ||
610 | hd= [EIDE] (E)IDE hard drive subsystem geometry | |
611 | Format: <cyl>,<head>,<sect> | |
612 | ||
613 | hd?= [HW] (E)IDE subsystem | |
614 | hd?lun= See Documentation/ide.txt. | |
615 | ||
616 | highmem=nn[KMG] [KNL,BOOT] forces the highmem zone to have an exact | |
617 | size of <nn>. This works even on boxes that have no | |
618 | highmem otherwise. This also works to reduce highmem | |
619 | size on bigger boxes. | |
620 | ||
54cdfdb4 TG |
621 | highres= [KNL] Enable/disable high resolution timer mode. |
622 | Valid parameters: "on", "off" | |
623 | Default: "on" | |
624 | ||
1da177e4 LT |
625 | hisax= [HW,ISDN] |
626 | See Documentation/isdn/README.HiSax. | |
627 | ||
628 | hugepages= [HW,IA-32,IA-64] Maximal number of HugeTLB pages. | |
629 | ||
1da177e4 | 630 | i8042.direct [HW] Put keyboard port into non-translated mode |
84eb8d06 ML |
631 | i8042.dumbkbd [HW] Pretend that controller can only read data from |
632 | keyboard and cannot control its state | |
1da177e4 LT |
633 | (Don't attempt to blink the leds) |
634 | i8042.noaux [HW] Don't check for auxiliary (== mouse) port | |
945ef0d4 | 635 | i8042.nokbd [HW] Don't check/create keyboard port |
1da177e4 LT |
636 | i8042.nomux [HW] Don't check presence of an active multiplexing |
637 | controller | |
638 | i8042.nopnp [HW] Don't use ACPIPnP / PnPBIOS to discover KBD/AUX | |
639 | controllers | |
640 | i8042.panicblink= | |
641 | [HW] Frequency with which keyboard LEDs should blink | |
642 | when kernel panics (default is 0.5 sec) | |
643 | i8042.reset [HW] Reset the controller during init and cleanup | |
644 | i8042.unlock [HW] Unlock (ignore) the keylock | |
645 | ||
646 | i810= [HW,DRM] | |
647 | ||
e70c9d5e DT |
648 | i8k.ignore_dmi [HW] Continue probing hardware even if DMI data |
649 | indicates that the driver is running on unsupported | |
650 | hardware. | |
1da177e4 LT |
651 | i8k.force [HW] Activate i8k driver even if SMM BIOS signature |
652 | does not match list of supported models. | |
653 | i8k.power_status | |
654 | [HW] Report power status in /proc/i8k | |
655 | (disabled by default) | |
656 | i8k.restricted [HW] Allow controlling fans only if SYS_ADMIN | |
657 | capability is set. | |
658 | ||
659 | ibmmcascsi= [HW,MCA,SCSI] IBM MicroChannel SCSI adapter | |
660 | See Documentation/mca.txt. | |
661 | ||
662 | icn= [HW,ISDN] | |
663 | Format: <io>[,<membase>[,<icn_id>[,<icn_id2>]]] | |
664 | ||
665 | ide= [HW] (E)IDE subsystem | |
666 | Format: ide=nodma or ide=doubler or ide=reverse | |
667 | See Documentation/ide.txt. | |
668 | ||
669 | ide?= [HW] (E)IDE subsystem | |
670 | Format: ide?=noprobe or chipset specific parameters. | |
671 | See Documentation/ide.txt. | |
a9913044 | 672 | |
1da177e4 LT |
673 | idebus= [HW] (E)IDE subsystem - VLB/PCI bus speed |
674 | See Documentation/ide.txt. | |
675 | ||
676 | idle= [HW] | |
677 | Format: idle=poll or idle=halt | |
a9913044 | 678 | |
79290822 IM |
679 | ignore_loglevel [KNL] |
680 | Ignore loglevel setting - this will print /all/ | |
681 | kernel messages to the console. Useful for debugging. | |
682 | ||
1da177e4 LT |
683 | ihash_entries= [KNL] |
684 | Set number of hash buckets for inode cache. | |
685 | ||
686 | in2000= [HW,SCSI] | |
687 | See header of drivers/scsi/in2000.c. | |
688 | ||
689 | init= [KNL] | |
690 | Format: <full_path> | |
691 | Run specified binary instead of /sbin/init as init | |
692 | process. | |
693 | ||
694 | initcall_debug [KNL] Trace initcalls as they are executed. Useful | |
695 | for working out where the kernel is dying during | |
696 | startup. | |
697 | ||
698 | initrd= [BOOT] Specify the location of the initial ramdisk | |
699 | ||
700 | inport.irq= [HW] Inport (ATI XL and Microsoft) busmouse driver | |
701 | Format: <irq> | |
702 | ||
2bd0fa3b JB |
703 | combined_mode= [HW] control which driver uses IDE ports in combined |
704 | mode: legacy IDE driver, libata, or both | |
705 | (in the libata case, libata.atapi_enabled=1 may be | |
706 | useful as well). Note that using the ide or libata | |
707 | options may affect your device naming (e.g. by | |
708 | changing hdc to sdb). | |
709 | Format: combined (default), ide, or libata | |
710 | ||
1da177e4 LT |
711 | inttest= [IA64] |
712 | ||
713 | io7= [HW] IO7 for Marvel based alpha systems | |
714 | See comment before marvel_specify_io7 in | |
715 | arch/alpha/kernel/core_marvel.c. | |
716 | ||
717 | ip= [IP_PNP] | |
718 | See Documentation/nfsroot.txt. | |
719 | ||
720 | ip2= [HW] Set IO/IRQ pairs for up to 4 IntelliPort boards | |
721 | See comment before ip2_setup() in drivers/char/ip2.c. | |
722 | ||
723 | ips= [HW,SCSI] Adaptec / IBM ServeRAID controller | |
724 | See header of drivers/scsi/ips.c. | |
725 | ||
72c4a13a SH |
726 | ports= [IP_VS_FTP] IPVS ftp helper module |
727 | Default is 21. | |
728 | Up to 8 (IP_VS_APP_MAX_PORTS) ports | |
729 | may be specified. | |
730 | Format: <port>,<port>.... | |
731 | ||
200803df AC |
732 | irqfixup [HW] |
733 | When an interrupt is not handled search all handlers | |
734 | for it. Intended to get systems with badly broken | |
735 | firmware running. | |
736 | ||
737 | irqpoll [HW] | |
738 | When an interrupt is not handled search all handlers | |
739 | for it. Also check all handlers each timer | |
740 | interrupt. Intended to get systems with badly broken | |
741 | firmware running. | |
742 | ||
1da177e4 | 743 | isapnp= [ISAPNP] |
a9913044 | 744 | Format: <RDP>,<reset>,<pci_scan>,<verbosity> |
1da177e4 LT |
745 | |
746 | isolcpus= [KNL,SMP] Isolate CPUs from the general scheduler. | |
22f2e280 DF |
747 | Format: |
748 | <cpu number>,...,<cpu number> | |
749 | or | |
750 | <cpu number>-<cpu number> (must be a positive range in ascending order) | |
751 | or a mixture | |
752 | <cpu number>,...,<cpu number>-<cpu number> | |
1da177e4 LT |
753 | This option can be used to specify one or more CPUs |
754 | to isolate from the general SMP balancing and scheduling | |
755 | algorithms. The only way to move a process onto or off | |
756 | an "isolated" CPU is via the CPU affinity syscalls. | |
757 | <cpu number> begins at 0 and the maximum value is | |
758 | "number of CPUs in system - 1". | |
759 | ||
760 | This option is the preferred way to isolate CPUs. The | |
a9913044 RD |
761 | alternative -- manually setting the CPU mask of all |
762 | tasks in the system -- can cause problems and | |
763 | suboptimal load balancer performance. | |
1da177e4 LT |
764 | |
765 | isp16= [HW,CD] | |
766 | Format: <io>,<irq>,<dma>,<setup> | |
767 | ||
a9913044 | 768 | iucv= [HW,NET] |
1da177e4 LT |
769 | |
770 | js= [HW,JOY] Analog joystick | |
771 | See Documentation/input/joystick.txt. | |
772 | ||
773 | keepinitrd [HW,ARM] | |
774 | ||
a9913044 | 775 | kstack=N [IA-32,X86-64] Print N words from the kernel stack |
1da177e4 LT |
776 | in oops dumps. |
777 | ||
778 | l2cr= [PPC] | |
779 | ||
a9913044 RD |
780 | lapic [IA-32,APIC] Enable the local APIC even if BIOS |
781 | disabled it. | |
1da177e4 LT |
782 | |
783 | lasi= [HW,SCSI] PARISC LASI driver for the 53c700 chip | |
784 | Format: addr:<io>,irq:<irq> | |
785 | ||
a9913044 RD |
786 | llsc*= [IA64] See function print_params() in |
787 | arch/ia64/sn/kernel/llsc4.c. | |
1da177e4 LT |
788 | |
789 | load_ramdisk= [RAM] List of ramdisks to load from floppy | |
790 | See Documentation/ramdisk.txt. | |
791 | ||
a6b25b67 RD |
792 | lockd.nlm_grace_period=P [NFS] Assign grace period. |
793 | Format: <integer> | |
1da177e4 | 794 | |
a6b25b67 RD |
795 | lockd.nlm_tcpport=N [NFS] Assign TCP port. |
796 | Format: <integer> | |
797 | ||
798 | lockd.nlm_timeout=T [NFS] Assign timeout value. | |
799 | Format: <integer> | |
800 | ||
801 | lockd.nlm_udpport=M [NFS] Assign UDP port. | |
802 | Format: <integer> | |
1da177e4 LT |
803 | |
804 | logibm.irq= [HW,MOUSE] Logitech Bus Mouse Driver | |
805 | Format: <irq> | |
806 | ||
807 | loglevel= All Kernel Messages with a loglevel smaller than the | |
808 | console loglevel will be printed to the console. It can | |
809 | also be changed with klogd or other programs. The | |
810 | loglevels are defined as follows: | |
811 | ||
812 | 0 (KERN_EMERG) system is unusable | |
813 | 1 (KERN_ALERT) action must be taken immediately | |
814 | 2 (KERN_CRIT) critical conditions | |
815 | 3 (KERN_ERR) error conditions | |
816 | 4 (KERN_WARNING) warning conditions | |
817 | 5 (KERN_NOTICE) normal but significant condition | |
818 | 6 (KERN_INFO) informational | |
819 | 7 (KERN_DEBUG) debug-level messages | |
820 | ||
821 | log_buf_len=n Sets the size of the printk ring buffer, in bytes. | |
a9913044 RD |
822 | Format: { n | nk | nM } |
823 | n must be a power of two. The default size | |
824 | is set in the kernel config file. | |
1da177e4 LT |
825 | |
826 | lp=0 [LP] Specify parallel ports to use, e.g, | |
827 | lp=port[,port...] lp=none,parport0 (lp0 not configured, lp1 uses | |
828 | lp=reset first parallel port). 'lp=0' disables the | |
829 | lp=auto printer driver. 'lp=reset' (which can be | |
830 | specified in addition to the ports) causes | |
831 | attached printers to be reset. Using | |
832 | lp=port1,port2,... specifies the parallel ports | |
833 | to associate lp devices with, starting with | |
834 | lp0. A port specification may be 'none' to skip | |
835 | that lp device, or a parport name such as | |
836 | 'parport0'. Specifying 'lp=auto' instead of a | |
837 | port specification list means that device IDs | |
838 | from each port should be examined, to see if | |
839 | an IEEE 1284-compliant printer is attached; if | |
840 | so, the driver will manage that printer. | |
841 | See also header of drivers/char/lp.c. | |
842 | ||
843 | lpj=n [KNL] | |
844 | Sets loops_per_jiffy to given constant, thus avoiding | |
845 | time-consuming boot-time autodetection (up to 250 ms per | |
846 | CPU). 0 enables autodetection (default). To determine | |
847 | the correct value for your kernel, boot with normal | |
848 | autodetection and see what value is printed. Note that | |
849 | on SMP systems the preset will be applied to all CPUs, | |
850 | which is likely to cause problems if your CPUs need | |
851 | significantly divergent settings. An incorrect value | |
852 | will cause delays in the kernel to be wrong, leading to | |
853 | unpredictable I/O errors and other breakage. Although | |
854 | unlikely, in the extreme case this might damage your | |
855 | hardware. | |
856 | ||
857 | ltpc= [NET] | |
858 | Format: <io>,<irq>,<dma> | |
859 | ||
a9913044 RD |
860 | mac5380= [HW,SCSI] Format: |
861 | <can_queue>,<cmd_per_lun>,<sg_tablesize>,<hostid>,<use_tags> | |
1da177e4 | 862 | |
a9913044 RD |
863 | mac53c9x= [HW,SCSI] Format: |
864 | <num_esps>,<disconnect>,<nosync>,<can_queue>,<cmd_per_lun>,<sg_tablesize>,<hostid>,<use_tags> | |
1da177e4 | 865 | |
a9913044 RD |
866 | machvec= [IA64] Force the use of a particular machine-vector |
867 | (machvec) in a generic kernel. | |
868 | Example: machvec=hpzx1_swiotlb | |
1da177e4 | 869 | |
a9913044 | 870 | max_loop= [LOOP] Maximum number of loopback devices that can |
1da177e4 LT |
871 | be mounted |
872 | Format: <1-256> | |
873 | ||
874 | maxcpus= [SMP] Maximum number of processors that an SMP kernel | |
78f92a82 RD |
875 | should make use of. |
876 | Using "nosmp" or "maxcpus=0" will disable SMP | |
877 | entirely (the MPS table probe still happens, though). | |
878 | A command-line option of "maxcpus=<NUM>", where <NUM> | |
879 | is an integer greater than 0, limits the maximum number | |
880 | of CPUs activated in SMP mode to <NUM>. | |
881 | Using "maxcpus=1" on an SMP kernel is the trivial | |
882 | case of an SMP kernel with only one CPU. | |
1da177e4 | 883 | |
2b2c3750 BP |
884 | max_addr=[KMG] [KNL,BOOT,ia64] All physical memory greater than or |
885 | equal to this physical address is ignored. | |
886 | ||
a9913044 | 887 | max_luns= [SCSI] Maximum number of LUNs to probe. |
1da177e4 LT |
888 | Should be between 1 and 2^32-1. |
889 | ||
890 | max_report_luns= | |
a9913044 | 891 | [SCSI] Maximum number of LUNs received. |
1da177e4 LT |
892 | Should be between 1 and 16384. |
893 | ||
894 | mca-pentium [BUGS=IA-32] | |
895 | ||
896 | mcatest= [IA-64] | |
897 | ||
898 | mcd= [HW,CD] | |
899 | Format: <port>,<irq>,<mitsumi_bug_93_wait> | |
900 | ||
901 | mcdx= [HW,CD] | |
902 | ||
903 | mce [IA-32] Machine Check Exception | |
904 | ||
905 | md= [HW] RAID subsystems devices and level | |
906 | See Documentation/md.txt. | |
a9913044 | 907 | |
1da177e4 LT |
908 | mdacon= [MDA] |
909 | Format: <first>,<last> | |
910 | Specifies range of consoles to be captured by the MDA. | |
a9913044 | 911 | |
1da177e4 LT |
912 | mem=nn[KMG] [KNL,BOOT] Force usage of a specific amount of memory |
913 | Amount of memory to be used when the kernel is not able | |
914 | to see the whole system memory or for test. | |
915 | [IA-32] Use together with memmap= to avoid physical | |
916 | address space collisions. Without memmap= PCI devices | |
917 | could be placed at addresses belonging to unused RAM. | |
918 | ||
919 | mem=nopentium [BUGS=IA-32] Disable usage of 4MB pages for kernel | |
920 | memory. | |
921 | ||
69cda7b1 | 922 | memmap=exactmap [KNL,IA-32,X86_64] Enable setting of an exact |
1da177e4 LT |
923 | E820 memory map, as specified by the user. |
924 | Such memmap=exactmap lines can be constructed based on | |
925 | BIOS output or other requirements. See the memmap=nn@ss | |
926 | option description. | |
927 | ||
928 | memmap=nn[KMG]@ss[KMG] | |
929 | [KNL] Force usage of a specific region of memory | |
930 | Region of memory to be used, from ss to ss+nn. | |
931 | ||
932 | memmap=nn[KMG]#ss[KMG] | |
933 | [KNL,ACPI] Mark specific memory as ACPI data. | |
934 | Region of memory to be used, from ss to ss+nn. | |
935 | ||
936 | memmap=nn[KMG]$ss[KMG] | |
937 | [KNL,ACPI] Mark specific memory as reserved. | |
938 | Region of memory to be used, from ss to ss+nn. | |
939 | ||
940 | meye.*= [HW] Set MotionEye Camera parameters | |
941 | See Documentation/video4linux/meye.txt. | |
942 | ||
943 | mga= [HW,DRM] | |
944 | ||
198e2f18 | 945 | migration_cost= |
946 | [KNL,SMP] debug: override scheduler migration costs | |
947 | Format: <level-1-usecs>,<level-2-usecs>,... | |
948 | This debugging option can be used to override the | |
949 | default scheduler migration cost matrix. The numbers | |
950 | are indexed by 'CPU domain distance'. | |
951 | E.g. migration_cost=1000,2000,3000 on an SMT NUMA | |
952 | box will set up an intra-core migration cost of | |
953 | 1 msec, an inter-core migration cost of 2 msecs, | |
954 | and an inter-node migration cost of 3 msecs. | |
955 | ||
956 | WARNING: using the wrong values here can break | |
957 | scheduler performance, so it's only for scheduler | |
958 | development purposes, not production environments. | |
959 | ||
960 | migration_debug= | |
961 | [KNL,SMP] migration cost auto-detect verbosity | |
962 | Format=<0|1|2> | |
963 | If a system's migration matrix reported at bootup | |
964 | seems erroneous then this option can be used to | |
965 | increase verbosity of the detection process. | |
966 | We default to 0 (no extra messages), 1 will print | |
967 | some more information, and 2 will be really | |
968 | verbose (probably only useful if you also have a | |
969 | serial console attached to the system). | |
970 | ||
971 | migration_factor= | |
972 | [KNL,SMP] multiply/divide migration costs by a factor | |
973 | Format=<percent> | |
974 | This debug option can be used to proportionally | |
975 | increase or decrease the auto-detected migration | |
976 | costs for all entries of the migration matrix. | |
977 | E.g. migration_factor=150 will increase migration | |
978 | costs by 50%. (and thus the scheduler will be less | |
979 | eager migrating cache-hot tasks) | |
980 | migration_factor=80 will decrease migration costs | |
981 | by 20%. (thus the scheduler will be more eager to | |
982 | migrate tasks) | |
983 | ||
984 | WARNING: using the wrong values here can break | |
985 | scheduler performance, so it's only for scheduler | |
986 | development purposes, not production environments. | |
987 | ||
1da177e4 LT |
988 | mousedev.tap_time= |
989 | [MOUSE] Maximum time between finger touching and | |
990 | leaving touchpad surface for touch to be considered | |
991 | a tap and be reported as a left button click (for | |
992 | touchpads working in absolute mode only). | |
993 | Format: <msecs> | |
994 | mousedev.xres= [MOUSE] Horizontal screen resolution, used for devices | |
995 | reporting absolute coordinates, such as tablets | |
996 | mousedev.yres= [MOUSE] Vertical screen resolution, used for devices | |
997 | reporting absolute coordinates, such as tablets | |
998 | ||
999 | mpu401= [HW,OSS] | |
1000 | Format: <io>,<irq> | |
1001 | ||
1002 | MTD_Partition= [MTD] | |
1003 | Format: <name>,<region-number>,<size>,<offset> | |
1004 | ||
a9913044 RD |
1005 | MTD_Region= [MTD] Format: |
1006 | <name>,<region-number>[,<base>,<size>,<buswidth>,<altbuswidth>] | |
1da177e4 LT |
1007 | |
1008 | mtdparts= [MTD] | |
1009 | See drivers/mtd/cmdline.c. | |
1010 | ||
1011 | mtouchusb.raw_coordinates= | |
a9913044 RD |
1012 | [HW] Make the MicroTouch USB driver use raw coordinates |
1013 | ('y', default) or cooked coordinates ('n') | |
1da177e4 LT |
1014 | |
1015 | n2= [NET] SDL Inc. RISCom/N2 synchronous serial card | |
1016 | ||
1017 | NCR_D700= [HW,SCSI] | |
1018 | See header of drivers/scsi/NCR_D700.c. | |
1019 | ||
1020 | ncr5380= [HW,SCSI] | |
1021 | ||
1022 | ncr53c400= [HW,SCSI] | |
1023 | ||
1024 | ncr53c400a= [HW,SCSI] | |
1025 | ||
1026 | ncr53c406a= [HW,SCSI] | |
1027 | ||
1028 | ncr53c8xx= [HW,SCSI] | |
1029 | ||
1030 | netdev= [NET] Network devices parameters | |
1031 | Format: <irq>,<io>,<mem_start>,<mem_end>,<name> | |
1032 | Note that mem_start is often overloaded to mean | |
1033 | something different and driver-specific. | |
a9913044 RD |
1034 | This usage is only documented in each driver source |
1035 | file if at all. | |
1036 | ||
1da177e4 LT |
1037 | nfsaddrs= [NFS] |
1038 | See Documentation/nfsroot.txt. | |
1039 | ||
1040 | nfsroot= [NFS] nfs root filesystem for disk-less boxes. | |
1041 | See Documentation/nfsroot.txt. | |
1042 | ||
a72b4422 TM |
1043 | nfs.callback_tcpport= |
1044 | [NFS] set the TCP port on which the NFSv4 callback | |
1045 | channel should listen. | |
1046 | ||
58df095b TM |
1047 | nfs.idmap_cache_timeout= |
1048 | [NFS] set the maximum lifetime for idmapper cache | |
1049 | entries. | |
1050 | ||
1da177e4 LT |
1051 | nmi_watchdog= [KNL,BUGS=IA-32] Debugging features for SMP kernels |
1052 | ||
1053 | no387 [BUGS=IA-32] Tells the kernel to use the 387 maths | |
1054 | emulation library even if a 387 maths coprocessor | |
1055 | is present. | |
1056 | ||
11ef697b KCA |
1057 | noacpi [LIBATA] Disables use of ACPI in libata suspend/resume |
1058 | when set. | |
1059 | Format: <int> | |
1060 | ||
3395ee05 PM |
1061 | noaliencache [MM, NUMA] Disables the allcoation of alien caches in |
1062 | the slab allocator. Saves per-node memory, but will | |
1063 | impact performance on real NUMA hardware. | |
1064 | ||
a9913044 RD |
1065 | noalign [KNL,ARM] |
1066 | ||
1da177e4 LT |
1067 | noapic [SMP,APIC] Tells the kernel to not make use of any |
1068 | IOAPICs that may be present in the system. | |
1069 | ||
1070 | noasync [HW,M68K] Disables async and sync negotiation for | |
1071 | all devices. | |
1072 | ||
1073 | nobats [PPC] Do not use BATs for mapping kernel lowmem | |
1074 | on "Classic" PPC cores. | |
1075 | ||
1076 | nocache [ARM] | |
a9913044 | 1077 | |
163ecdff SN |
1078 | nodelayacct [KNL] Disable per-task delay accounting |
1079 | ||
1da177e4 LT |
1080 | nodisconnect [HW,SCSI,M68K] Disables SCSI disconnects. |
1081 | ||
1082 | noexec [IA-64] | |
1083 | ||
a9913044 | 1084 | noexec [IA-32,X86-64] |
1da177e4 LT |
1085 | noexec=on: enable non-executable mappings (default) |
1086 | noexec=off: disable nn-executable mappings | |
1087 | ||
4f886511 CE |
1088 | nofxsr [BUGS=IA-32] Disables x86 floating point extended |
1089 | register save and restore. The kernel will only save | |
1090 | legacy floating-point registers on task switch. | |
1da177e4 LT |
1091 | |
1092 | nohlt [BUGS=ARM] | |
a9913044 | 1093 | |
1da177e4 LT |
1094 | no-hlt [BUGS=IA-32] Tells the kernel that the hlt |
1095 | instruction doesn't work correctly and not to | |
1096 | use it. | |
1097 | ||
1098 | nohalt [IA-64] Tells the kernel not to use the power saving | |
1099 | function PAL_HALT_LIGHT when idle. This increases | |
1100 | power-consumption. On the positive side, it reduces | |
1101 | interrupt wake-up latency, which may improve performance | |
1102 | in certain environments such as networked servers or | |
1103 | real-time systems. | |
1104 | ||
79bf2bb3 TG |
1105 | nohz= [KNL] Boottime enable/disable dynamic ticks |
1106 | Valid arguments: on, off | |
1107 | Default: on | |
1108 | ||
8542b200 ZA |
1109 | noirqbalance [IA-32,SMP,KNL] Disable kernel irq balancing |
1110 | ||
1da177e4 LT |
1111 | noirqdebug [IA-32] Disables the code which attempts to detect and |
1112 | disable unhandled interrupt sources. | |
1113 | ||
8542b200 ZA |
1114 | no_timer_check [IA-32,X86_64,APIC] Disables the code which tests for |
1115 | broken timer IRQ sources. | |
1116 | ||
1da177e4 LT |
1117 | noisapnp [ISAPNP] Disables ISA PnP code. |
1118 | ||
1119 | noinitrd [RAM] Tells the kernel not to load any configured | |
1120 | initial RAM disk. | |
1121 | ||
1122 | nointroute [IA-64] | |
1123 | ||
1124 | nolapic [IA-32,APIC] Do not enable or use the local APIC. | |
1125 | ||
ad62ca2b TG |
1126 | nolapic_timer [IA-32,APIC] Do not use the local APIC timer. |
1127 | ||
1da177e4 LT |
1128 | noltlbs [PPC] Do not use large page/tlb entries for kernel |
1129 | lowmem mapping on PPC40x. | |
1130 | ||
312f1f01 H |
1131 | nomca [IA-64] Disable machine check abort handling |
1132 | ||
abe37e5a H |
1133 | nomce [IA-32] Machine Check Exception |
1134 | ||
1da177e4 LT |
1135 | noresidual [PPC] Don't use residual data on PReP machines. |
1136 | ||
a9913044 RD |
1137 | noresume [SWSUSP] Disables resume and restores original swap |
1138 | space. | |
1139 | ||
1da177e4 LT |
1140 | no-scroll [VGA] Disables scrollback. |
1141 | This is required for the Braillex ib80-piezo Braille | |
1142 | reader made by F.H. Papenmeier (Germany). | |
1143 | ||
1144 | nosbagart [IA-64] | |
1145 | ||
4f886511 CE |
1146 | nosep [BUGS=IA-32] Disables x86 SYSENTER/SYSEXIT support. |
1147 | ||
1da177e4 LT |
1148 | nosmp [SMP] Tells an SMP kernel to act as a UP kernel. |
1149 | ||
1150 | nosync [HW,M68K] Disables sync negotiation for all devices. | |
1151 | ||
1152 | notsc [BUGS=IA-32] Disable Time Stamp Counter | |
1153 | ||
1154 | nousb [USB] Disable the USB subsystem | |
1155 | ||
1156 | nowb [ARM] | |
a9913044 | 1157 | |
a61c2d78 DJ |
1158 | nr_uarts= [SERIAL] maximum number of UARTs to be registered. |
1159 | ||
1da177e4 LT |
1160 | opl3= [HW,OSS] |
1161 | Format: <io> | |
1162 | ||
a9913044 RD |
1163 | opl3sa2= [HW,OSS] Format: |
1164 | <io>,<irq>,<dma>,<dma2>,<mss_io>,<mpu_io>,<ymode>,<loopback>[,<isapnp>,<multiple] | |
1165 | ||
1da177e4 LT |
1166 | oprofile.timer= [HW] |
1167 | Use timer interrupt instead of performance counters | |
1168 | ||
1169 | optcd= [HW,CD] | |
1170 | Format: <io> | |
1171 | ||
1172 | osst= [HW,SCSI] SCSI Tape Driver | |
1173 | Format: <buffer_size>,<write_threshold> | |
1174 | See also Documentation/scsi/st.txt. | |
1175 | ||
1176 | panic= [KNL] Kernel behaviour on panic | |
1177 | Format: <timeout> | |
1178 | ||
1179 | parkbd.port= [HW] Parallel port number the keyboard adapter is | |
1180 | connected to, default is 0. | |
1181 | Format: <parport#> | |
1182 | parkbd.mode= [HW] Parallel port keyboard adapter mode of operation, | |
1183 | 0 for XT, 1 for AT (default is AT). | |
a9913044 RD |
1184 | Format: <mode> |
1185 | ||
1186 | parport= [HW,PPT] Specify parallel ports. 0 disables. | |
1187 | Format: { 0 | auto | 0xBBB[,IRQ[,DMA]] } | |
1188 | Use 'auto' to force the driver to use any | |
1189 | IRQ/DMA settings detected (the default is to | |
1190 | ignore detected IRQ/DMA settings because of | |
1191 | possible conflicts). You can specify the base | |
1192 | address, IRQ, and DMA settings; IRQ and DMA | |
1193 | should be numbers, or 'auto' (for using detected | |
1194 | settings on that particular port), or 'nofifo' | |
1195 | (to avoid using a FIFO even if it is detected). | |
1196 | Parallel ports are assigned in the order they | |
1197 | are specified on the command line, starting | |
1198 | with parport0. | |
1199 | ||
1200 | parport_init_mode= [HW,PPT] | |
1201 | Configure VIA parallel port to operate in | |
1202 | a specific mode. This is necessary on Pegasos | |
1203 | computer where firmware has no options for setting | |
1204 | up parallel port mode and sets it to spp. | |
1205 | Currently this function knows 686a and 8231 chips. | |
1da177e4 LT |
1206 | Format: [spp|ps2|epp|ecp|ecpepp] |
1207 | ||
a9913044 RD |
1208 | pas2= [HW,OSS] Format: |
1209 | <io>,<irq>,<dma>,<dma16>,<sb_io>,<sb_irq>,<sb_dma>,<sb_dma16> | |
1210 | ||
1da177e4 LT |
1211 | pas16= [HW,SCSI] |
1212 | See header of drivers/scsi/pas16.c. | |
1213 | ||
dd287796 AM |
1214 | pause_on_oops= |
1215 | Halt all CPUs after the first oops has been printed for | |
1216 | the specified number of seconds. This is to be used if | |
1217 | your oopses keep scrolling off the screen. | |
1218 | ||
1da177e4 LT |
1219 | pcbit= [HW,ISDN] |
1220 | ||
1221 | pcd. [PARIDE] | |
1222 | See header of drivers/block/paride/pcd.c. | |
1223 | See also Documentation/paride.txt. | |
1224 | ||
a9913044 RD |
1225 | pci=option[,option...] [PCI] various PCI subsystem options: |
1226 | off [IA-32] don't probe for the PCI bus | |
1227 | bios [IA-32] force use of PCI BIOS, don't access | |
1228 | the hardware directly. Use this if your machine | |
1229 | has a non-standard PCI host bridge. | |
1230 | nobios [IA-32] disallow use of PCI BIOS, only direct | |
1231 | hardware access methods are allowed. Use this | |
1232 | if you experience crashes upon bootup and you | |
1233 | suspect they are caused by the BIOS. | |
1234 | conf1 [IA-32] Force use of PCI Configuration | |
1235 | Mechanism 1. | |
1236 | conf2 [IA-32] Force use of PCI Configuration | |
1237 | Mechanism 2. | |
61be6d66 BH |
1238 | nommconf [IA-32,X86_64] Disable use of MMCONFIG for PCI |
1239 | Configuration | |
309e57df MW |
1240 | nomsi [MSI] If the PCI_MSI kernel config parameter is |
1241 | enabled, this kernel boot option can be used to | |
1242 | disable the use of MSI interrupts system-wide. | |
a9913044 RD |
1243 | nosort [IA-32] Don't sort PCI devices according to |
1244 | order given by the PCI BIOS. This sorting is | |
1245 | done to get a device order compatible with | |
1246 | older kernels. | |
1247 | biosirq [IA-32] Use PCI BIOS calls to get the interrupt | |
1248 | routing table. These calls are known to be buggy | |
1249 | on several machines and they hang the machine | |
1250 | when used, but on other computers it's the only | |
1251 | way to get the interrupt routing table. Try | |
1252 | this option if the kernel is unable to allocate | |
1253 | IRQs or discover secondary PCI buses on your | |
1254 | motherboard. | |
1255 | rom [IA-32] Assign address space to expansion ROMs. | |
1256 | Use with caution as certain devices share | |
1257 | address decoders between ROMs and other | |
1258 | resources. | |
1259 | irqmask=0xMMMM [IA-32] Set a bit mask of IRQs allowed to be | |
1260 | assigned automatically to PCI devices. You can | |
1261 | make the kernel exclude IRQs of your ISA cards | |
1262 | this way. | |
120bb424 | 1263 | pirqaddr=0xAAAAA [IA-32] Specify the physical address |
a9913044 RD |
1264 | of the PIRQ table (normally generated |
1265 | by the BIOS) if it is outside the | |
1266 | F0000h-100000h range. | |
1267 | lastbus=N [IA-32] Scan all buses thru bus #N. Can be | |
1268 | useful if the kernel is unable to find your | |
1269 | secondary buses and you want to tell it | |
1270 | explicitly which ones they are. | |
1271 | assign-busses [IA-32] Always assign all PCI bus | |
1272 | numbers ourselves, overriding | |
1273 | whatever the firmware may have done. | |
1274 | usepirqmask [IA-32] Honor the possible IRQ mask stored | |
1275 | in the BIOS $PIR table. This is needed on | |
1276 | some systems with broken BIOSes, notably | |
1277 | some HP Pavilion N5400 and Omnibook XE3 | |
1278 | notebooks. This will have no effect if ACPI | |
1279 | IRQ routing is enabled. | |
1280 | noacpi [IA-32] Do not use ACPI for IRQ routing | |
1281 | or for PCI scanning. | |
1282 | routeirq Do IRQ routing for all PCI devices. | |
1283 | This is normally done in pci_enable_device(), | |
1284 | so this option is a temporary workaround | |
1285 | for broken drivers that don't call it. | |
1286 | firmware [ARM] Do not re-enumerate the bus but instead | |
1287 | just use the configuration from the | |
1288 | bootloader. This is currently used on | |
1289 | IXP2000 systems where the bus has to be | |
1290 | configured a certain way for adjunct CPUs. | |
0637a70a AK |
1291 | noearly [X86] Don't do any early type 1 scanning. |
1292 | This might help on some broken boards which | |
1293 | machine check when some devices' config space | |
1294 | is read. But various workarounds are disabled | |
1295 | and some IOMMU drivers will not work. | |
6b4b78fe MD |
1296 | bfsort Sort PCI devices into breadth-first order. |
1297 | This sorting is done to get a device | |
1298 | order compatible with older (<= 2.4) kernels. | |
1299 | nobfsort Don't sort PCI devices into breadth-first order. | |
4516a618 AN |
1300 | cbiosize=nn[KMG] The fixed amount of bus space which is |
1301 | reserved for the CardBus bridge's IO window. | |
1302 | The default value is 256 bytes. | |
1303 | cbmemsize=nn[KMG] The fixed amount of bus space which is | |
1304 | reserved for the CardBus bridge's memory | |
1305 | window. The default value is 64 megabytes. | |
6b4b78fe | 1306 | |
1da177e4 LT |
1307 | pcmv= [HW,PCMCIA] BadgePAD 4 |
1308 | ||
1309 | pd. [PARIDE] | |
1310 | See Documentation/paride.txt. | |
1311 | ||
1312 | pdcchassis= [PARISC,HW] Disable/Enable PDC Chassis Status codes at | |
1313 | boot time. | |
1314 | Format: { 0 | 1 } | |
1315 | See arch/parisc/kernel/pdc_chassis.c | |
1316 | ||
1317 | pf. [PARIDE] | |
1318 | See Documentation/paride.txt. | |
1319 | ||
1320 | pg. [PARIDE] | |
1321 | See Documentation/paride.txt. | |
1322 | ||
1323 | pirq= [SMP,APIC] Manual mp-table setup | |
1324 | See Documentation/i386/IO-APIC.txt. | |
1325 | ||
1326 | plip= [PPT,NET] Parallel port network link | |
1327 | Format: { parport<nr> | timid | 0 } | |
1328 | See also Documentation/parport.txt. | |
1329 | ||
1330 | pnpacpi= [ACPI] | |
1331 | { off } | |
1332 | ||
1333 | pnpbios= [ISAPNP] | |
1334 | { on | off | curr | res | no-curr | no-res } | |
1335 | ||
1336 | pnp_reserve_irq= | |
1337 | [ISAPNP] Exclude IRQs for the autoconfiguration | |
1338 | ||
1339 | pnp_reserve_dma= | |
1340 | [ISAPNP] Exclude DMAs for the autoconfiguration | |
1341 | ||
1342 | pnp_reserve_io= [ISAPNP] Exclude I/O ports for the autoconfiguration | |
a9913044 | 1343 | Ranges are in pairs (I/O port base and size). |
1da177e4 LT |
1344 | |
1345 | pnp_reserve_mem= | |
a9913044 RD |
1346 | [ISAPNP] Exclude memory regions for the |
1347 | autoconfiguration. | |
1da177e4 LT |
1348 | Ranges are in pairs (memory base and size). |
1349 | ||
1350 | profile= [KNL] Enable kernel profiling via /proc/profile | |
a9913044 RD |
1351 | Format: [schedule,]<number> |
1352 | Param: "schedule" - profile schedule points. | |
1353 | Param: <number> - step/bucket size as a power of 2 for | |
1354 | statistical time based profiling. | |
ece8a684 | 1355 | Param: "sleep" - profile D-state sleeping (millisecs) |
1da177e4 | 1356 | |
a9913044 | 1357 | processor.max_cstate= [HW,ACPI] |
1da177e4 LT |
1358 | Limit processor to maximum C-state |
1359 | max_cstate=9 overrides any DMI blacklist limit. | |
1360 | ||
41c0d868 LB |
1361 | processor.nocst [HW,ACPI] |
1362 | Ignore the _CST method to determine C-states, | |
1363 | instead using the legacy FADT method | |
1364 | ||
1da177e4 LT |
1365 | prompt_ramdisk= [RAM] List of RAM disks to prompt for floppy disk |
1366 | before loading. | |
1367 | See Documentation/ramdisk.txt. | |
1368 | ||
a9913044 RD |
1369 | psmouse.proto= [HW,MOUSE] Highest PS2 mouse protocol extension to |
1370 | probe for; one of (bare|imps|exps|lifebook|any). | |
1da177e4 LT |
1371 | psmouse.rate= [HW,MOUSE] Set desired mouse report rate, in reports |
1372 | per second. | |
a9913044 RD |
1373 | psmouse.resetafter= [HW,MOUSE] |
1374 | Try to reset the device after so many bad packets | |
1da177e4 LT |
1375 | (0 = never). |
1376 | psmouse.resolution= | |
1377 | [HW,MOUSE] Set desired mouse resolution, in dpi. | |
1378 | psmouse.smartscroll= | |
a9913044 | 1379 | [HW,MOUSE] Controls Logitech smartscroll autorepeat. |
1da177e4 LT |
1380 | 0 = disabled, 1 = enabled (default). |
1381 | ||
1382 | pss= [HW,OSS] Personal Sound System (ECHO ESC614) | |
a9913044 RD |
1383 | Format: |
1384 | <io>,<mss_io>,<mss_irq>,<mss_dma>,<mpu_io>,<mpu_irq> | |
1da177e4 LT |
1385 | |
1386 | pt. [PARIDE] | |
1387 | See Documentation/paride.txt. | |
1388 | ||
7d2c502f | 1389 | quiet [KNL] Disable most log messages |
a9913044 | 1390 | |
1da177e4 LT |
1391 | r128= [HW,DRM] |
1392 | ||
1393 | raid= [HW,RAID] | |
1394 | See Documentation/md.txt. | |
1395 | ||
1396 | ramdisk= [RAM] Sizes of RAM disks in kilobytes [deprecated] | |
1397 | See Documentation/ramdisk.txt. | |
1398 | ||
a9913044 | 1399 | ramdisk_blocksize= [RAM] |
1da177e4 | 1400 | See Documentation/ramdisk.txt. |
a9913044 | 1401 | |
1da177e4 LT |
1402 | ramdisk_size= [RAM] Sizes of RAM disks in kilobytes |
1403 | New name for the ramdisk parameter. | |
1404 | See Documentation/ramdisk.txt. | |
1405 | ||
21a1ea9e DS |
1406 | rcu.blimit= [KNL,BOOT] Set maximum number of finished |
1407 | RCU callbacks to process in one batch. | |
1408 | ||
1409 | rcu.qhimark= [KNL,BOOT] Set threshold of queued | |
1410 | RCU callbacks over which batch limiting is disabled. | |
1411 | ||
1412 | rcu.qlowmark= [KNL,BOOT] Set threshold of queued | |
1413 | RCU callbacks below which batch limiting is re-enabled. | |
1414 | ||
ffdfc409 OJ |
1415 | rdinit= [KNL] |
1416 | Format: <full_path> | |
1417 | Run specified binary instead of /init from the ramdisk, | |
1418 | used for early userspace startup. See initrd. | |
1419 | ||
1da177e4 LT |
1420 | reboot= [BUGS=IA-32,BUGS=ARM,BUGS=IA-64] Rebooting mode |
1421 | Format: <reboot_mode>[,<reboot_mode2>[,...]] | |
f3e299fe | 1422 | See arch/*/kernel/reboot.c or arch/*/kernel/process.c |
1da177e4 LT |
1423 | |
1424 | reserve= [KNL,BUGS] Force the kernel to ignore some iomem area | |
1425 | ||
461a9aff ZA |
1426 | reservetop= [IA-32] |
1427 | Format: nn[KMG] | |
1428 | Reserves a hole at the top of the kernel virtual | |
1429 | address space. | |
1430 | ||
7e96287d VG |
1431 | reset_devices [KNL] Force drivers to reset the underlying device |
1432 | during initialization. | |
1433 | ||
a9913044 RD |
1434 | resume= [SWSUSP] |
1435 | Specify the partition device for software suspend | |
1da177e4 | 1436 | |
ecbd0da1 RW |
1437 | resume_offset= [SWSUSP] |
1438 | Specify the offset from the beginning of the partition | |
1439 | given by "resume=" at which the swap header is located, | |
1440 | in <PAGE_SIZE> units (needed only for swap files). | |
1441 | See Documentation/power/swsusp-and-swap-files.txt | |
1442 | ||
0a7b35cb MN |
1443 | retain_initrd [RAM] Keep initrd memory after extraction |
1444 | ||
1da177e4 LT |
1445 | rhash_entries= [KNL,NET] |
1446 | Set number of hash buckets for route cache | |
1447 | ||
1448 | riscom8= [HW,SERIAL] | |
1449 | Format: <io_board1>[,<io_board2>[,...<io_boardN>]] | |
1450 | ||
1451 | ro [KNL] Mount root device read-only on boot | |
1452 | ||
1453 | root= [KNL] Root filesystem | |
1454 | ||
1455 | rootdelay= [KNL] Delay (in seconds) to pause before attempting to | |
1456 | mount the root filesystem | |
1457 | ||
1458 | rootflags= [KNL] Set root filesystem mount option string | |
1459 | ||
1460 | rootfstype= [KNL] Set root filesystem type | |
1461 | ||
1462 | rw [KNL] Mount root device read-write on boot | |
1463 | ||
1464 | S [KNL] Run init in single mode | |
1465 | ||
1466 | sa1100ir [NET] | |
1467 | See drivers/net/irda/sa1100_ir.c. | |
1468 | ||
1469 | sb= [HW,OSS] | |
1470 | Format: <io>,<irq>,<dma>,<dma2> | |
1471 | ||
1472 | sbni= [NET] Granch SBNI12 leased line adapter | |
a9913044 | 1473 | |
1da177e4 LT |
1474 | sbpcd= [HW,CD] Soundblaster CD adapter |
1475 | Format: <io>,<type> | |
1476 | See a comment before function sbpcd_setup() in | |
1477 | drivers/cdrom/sbpcd.c. | |
1478 | ||
1479 | sc1200wdt= [HW,WDT] SC1200 WDT (watchdog) driver | |
1480 | Format: <io>[,<timeout>[,<isapnp>]] | |
1481 | ||
1482 | scsi_debug_*= [SCSI] | |
1483 | See drivers/scsi/scsi_debug.c. | |
1484 | ||
1485 | scsi_default_dev_flags= | |
1486 | [SCSI] SCSI default device flags | |
1487 | Format: <integer> | |
1488 | ||
1489 | scsi_dev_flags= [SCSI] Black/white list entry for vendor and model | |
1490 | Format: <vendor>:<model>:<flags> | |
1491 | (flags are integer value) | |
1492 | ||
1493 | scsi_logging= [SCSI] | |
1494 | ||
3e082a91 MW |
1495 | scsi_mod.scan= [SCSI] sync (default) scans SCSI busses as they are |
1496 | discovered. async scans them in kernel threads, | |
1497 | allowing boot to proceed. none ignores them, expecting | |
1498 | user space to do the scan. | |
1499 | ||
1da177e4 LT |
1500 | selinux [SELINUX] Disable or enable SELinux at boot time. |
1501 | Format: { "0" | "1" } | |
1502 | See security/selinux/Kconfig help text. | |
1503 | 0 -- disable. | |
1504 | 1 -- enable. | |
1505 | Default value is set via kernel config option. | |
1506 | If enabled at boot time, /selinux/disable can be used | |
1507 | later to disable prior to initial policy load. | |
1508 | ||
4e5ab4cb JM |
1509 | selinux_compat_net = |
1510 | [SELINUX] Set initial selinux_compat_net flag value. | |
1511 | Format: { "0" | "1" } | |
1512 | 0 -- use new secmark-based packet controls | |
1513 | 1 -- use legacy packet controls | |
1514 | Default value is 0 (preferred). | |
1515 | Value can be changed at runtime via | |
1516 | /selinux/compat_net. | |
1517 | ||
1da177e4 LT |
1518 | serialnumber [BUGS=IA-32] |
1519 | ||
a9913044 RD |
1520 | sg_def_reserved_size= [SCSI] |
1521 | ||
1da177e4 LT |
1522 | shapers= [NET] |
1523 | Maximal number of shapers. | |
a9913044 | 1524 | |
1da177e4 LT |
1525 | sim710= [SCSI,HW] |
1526 | See header of drivers/scsi/sim710.c. | |
1527 | ||
1528 | simeth= [IA-64] | |
1529 | simscsi= | |
a9913044 | 1530 | |
1da177e4 LT |
1531 | sjcd= [HW,CD] |
1532 | Format: <io>,<irq>,<dma> | |
1533 | See header of drivers/cdrom/sjcd.c. | |
1534 | ||
1535 | slram= [HW,MTD] | |
1536 | ||
1537 | smart2= [HW] | |
1538 | Format: <io1>[,<io2>[,...,<io8>]] | |
1539 | ||
1540 | snd-ad1816a= [HW,ALSA] | |
1541 | ||
1542 | snd-ad1848= [HW,ALSA] | |
1543 | ||
1544 | snd-ali5451= [HW,ALSA] | |
1545 | ||
1546 | snd-als100= [HW,ALSA] | |
1547 | ||
1548 | snd-als4000= [HW,ALSA] | |
1549 | ||
1550 | snd-azt2320= [HW,ALSA] | |
1551 | ||
1552 | snd-cmi8330= [HW,ALSA] | |
1553 | ||
1554 | snd-cmipci= [HW,ALSA] | |
1555 | ||
1556 | snd-cs4231= [HW,ALSA] | |
1557 | ||
1558 | snd-cs4232= [HW,ALSA] | |
1559 | ||
1560 | snd-cs4236= [HW,ALSA] | |
1561 | ||
1562 | snd-cs4281= [HW,ALSA] | |
1563 | ||
1564 | snd-cs46xx= [HW,ALSA] | |
1565 | ||
1566 | snd-dt019x= [HW,ALSA] | |
1567 | ||
1568 | snd-dummy= [HW,ALSA] | |
1569 | ||
1570 | snd-emu10k1= [HW,ALSA] | |
1571 | ||
1572 | snd-ens1370= [HW,ALSA] | |
1573 | ||
1574 | snd-ens1371= [HW,ALSA] | |
1575 | ||
1576 | snd-es968= [HW,ALSA] | |
1577 | ||
1578 | snd-es1688= [HW,ALSA] | |
1579 | ||
1580 | snd-es18xx= [HW,ALSA] | |
1581 | ||
1582 | snd-es1938= [HW,ALSA] | |
1583 | ||
1584 | snd-es1968= [HW,ALSA] | |
1585 | ||
1586 | snd-fm801= [HW,ALSA] | |
1587 | ||
1588 | snd-gusclassic= [HW,ALSA] | |
1589 | ||
1590 | snd-gusextreme= [HW,ALSA] | |
1591 | ||
1592 | snd-gusmax= [HW,ALSA] | |
1593 | ||
1594 | snd-hdsp= [HW,ALSA] | |
1595 | ||
1596 | snd-ice1712= [HW,ALSA] | |
1597 | ||
1598 | snd-intel8x0= [HW,ALSA] | |
1599 | ||
1600 | snd-interwave= [HW,ALSA] | |
1601 | ||
1602 | snd-interwave-stb= | |
1603 | [HW,ALSA] | |
1604 | ||
1605 | snd-korg1212= [HW,ALSA] | |
1606 | ||
1607 | snd-maestro3= [HW,ALSA] | |
1608 | ||
1609 | snd-mpu401= [HW,ALSA] | |
1610 | ||
1611 | snd-mtpav= [HW,ALSA] | |
1612 | ||
1613 | snd-nm256= [HW,ALSA] | |
1614 | ||
1615 | snd-opl3sa2= [HW,ALSA] | |
1616 | ||
1617 | snd-opti92x-ad1848= | |
1618 | [HW,ALSA] | |
1619 | ||
1620 | snd-opti92x-cs4231= | |
1621 | [HW,ALSA] | |
1622 | ||
1623 | snd-opti93x= [HW,ALSA] | |
1624 | ||
1625 | snd-pmac= [HW,ALSA] | |
1626 | ||
1627 | snd-rme32= [HW,ALSA] | |
1628 | ||
1629 | snd-rme96= [HW,ALSA] | |
1630 | ||
1631 | snd-rme9652= [HW,ALSA] | |
1632 | ||
1633 | snd-sb8= [HW,ALSA] | |
1634 | ||
1635 | snd-sb16= [HW,ALSA] | |
1636 | ||
1637 | snd-sbawe= [HW,ALSA] | |
1638 | ||
1639 | snd-serial= [HW,ALSA] | |
1640 | ||
1641 | snd-sgalaxy= [HW,ALSA] | |
1642 | ||
1643 | snd-sonicvibes= [HW,ALSA] | |
1644 | ||
1645 | snd-sun-amd7930= | |
1646 | [HW,ALSA] | |
1647 | ||
1648 | snd-sun-cs4231= [HW,ALSA] | |
1649 | ||
1650 | snd-trident= [HW,ALSA] | |
1651 | ||
1652 | snd-usb-audio= [HW,ALSA,USB] | |
1653 | ||
1654 | snd-via82xx= [HW,ALSA] | |
1655 | ||
1656 | snd-virmidi= [HW,ALSA] | |
1657 | ||
1658 | snd-wavefront= [HW,ALSA] | |
1659 | ||
1660 | snd-ymfpci= [HW,ALSA] | |
a9913044 | 1661 | |
1da177e4 LT |
1662 | sonycd535= [HW,CD] |
1663 | Format: <io>[,<irq>] | |
1664 | ||
1665 | sonypi.*= [HW] Sony Programmable I/O Control Device driver | |
1666 | See Documentation/sonypi.txt | |
1667 | ||
1668 | specialix= [HW,SERIAL] Specialix multi-serial port adapter | |
1669 | See Documentation/specialix.txt. | |
1670 | ||
1671 | spia_io_base= [HW,MTD] | |
1672 | spia_fio_base= | |
1673 | spia_pedr= | |
1674 | spia_peddr= | |
1675 | ||
1676 | sscape= [HW,OSS] | |
1677 | Format: <io>,<irq>,<dma>,<mpu_io>,<mpu_irq> | |
a9913044 | 1678 | |
1da177e4 LT |
1679 | st= [HW,SCSI] SCSI tape parameters (buffers, etc.) |
1680 | See Documentation/scsi/st.txt. | |
1681 | ||
1682 | st0x= [HW,SCSI] | |
1683 | See header of drivers/scsi/seagate.c. | |
1684 | ||
1685 | sti= [PARISC,HW] | |
1686 | Format: <num> | |
1687 | Set the STI (builtin display/keyboard on the HP-PARISC | |
1688 | machines) console (graphic card) which should be used | |
1689 | as the initial boot-console. | |
1690 | See also comment in drivers/video/console/sticore.c. | |
1691 | ||
1692 | sti_font= [HW] | |
1693 | See comment in drivers/video/console/sticore.c. | |
1694 | ||
1695 | stifb= [HW] | |
1696 | Format: bpp:<bpp1>[:<bpp2>[:<bpp3>...]] | |
1697 | ||
42a7fc4a GB |
1698 | sunrpc.pool_mode= |
1699 | [NFS] | |
1700 | Control how the NFS server code allocates CPUs to | |
1701 | service thread pools. Depending on how many NICs | |
1702 | you have and where their interrupts are bound, this | |
1703 | option will affect which CPUs will do NFS serving. | |
1704 | Note: this parameter cannot be changed while the | |
1705 | NFS server is running. | |
1706 | ||
1707 | auto the server chooses an appropriate mode | |
1708 | automatically using heuristics | |
1709 | global a single global pool contains all CPUs | |
1710 | percpu one pool for each CPU | |
1711 | pernode one pool for each NUMA node (equivalent | |
1712 | to global on non-NUMA machines) | |
1713 | ||
1da177e4 | 1714 | swiotlb= [IA-64] Number of I/O TLB slabs |
a9913044 | 1715 | |
1da177e4 LT |
1716 | switches= [HW,M68k] |
1717 | ||
1718 | sym53c416= [HW,SCSI] | |
1719 | See header of drivers/scsi/sym53c416.c. | |
1720 | ||
5d6f647f IM |
1721 | sysrq_always_enabled |
1722 | [KNL] | |
1723 | Ignore sysrq setting - this boot parameter will | |
1724 | neutralize any effect of /proc/sys/kernel/sysrq. | |
1725 | Useful for debugging. | |
1726 | ||
1da177e4 LT |
1727 | t128= [HW,SCSI] |
1728 | See header of drivers/scsi/t128.c. | |
1729 | ||
1730 | tdfx= [HW,DRM] | |
1731 | ||
1732 | thash_entries= [KNL,NET] | |
1733 | Set number of hash buckets for TCP connection | |
1734 | ||
1735 | time Show timing data prefixed to each printk message line | |
1736 | ||
734efb46 | 1737 | clocksource= [GENERIC_TIME] Override the default clocksource |
1738 | Override the default clocksource and use the clocksource | |
1739 | with the name specified. | |
1740 | ||
1da177e4 LT |
1741 | tipar.timeout= [HW,PPT] |
1742 | Set communications timeout in tenths of a second | |
1743 | (default 15). | |
1744 | ||
1745 | tipar.delay= [HW,PPT] | |
1746 | Set inter-bit delay in microseconds (default 10). | |
1747 | ||
1748 | tmc8xx= [HW,SCSI] | |
1749 | See header of drivers/scsi/seagate.c. | |
1750 | ||
1751 | tmscsim= [HW,SCSI] | |
1752 | See comment before function dc390_setup() in | |
1753 | drivers/scsi/tmscsim.c. | |
1754 | ||
1755 | tp720= [HW,PS2] | |
1756 | ||
1757 | trix= [HW,OSS] MediaTrix AudioTrix Pro | |
a9913044 RD |
1758 | Format: |
1759 | <io>,<irq>,<dma>,<dma2>,<sb_io>,<sb_irq>,<sb_dma>,<mpu_io>,<mpu_irq> | |
1760 | ||
1da177e4 LT |
1761 | tsdev.xres= [TS] Horizontal screen resolution. |
1762 | tsdev.yres= [TS] Vertical screen resolution. | |
1763 | ||
a9913044 RD |
1764 | turbografx.map[2|3]= [HW,JOY] |
1765 | TurboGraFX parallel port interface | |
1766 | Format: | |
1767 | <port#>,<js1>,<js2>,<js3>,<js4>,<js5>,<js6>,<js7> | |
1da177e4 LT |
1768 | See also Documentation/input/joystick-parport.txt |
1769 | ||
1770 | u14-34f= [HW,SCSI] UltraStor 14F/34F SCSI host adapter | |
1771 | See header of drivers/scsi/u14-34f.c. | |
1772 | ||
1773 | uart401= [HW,OSS] | |
1774 | Format: <io>,<irq> | |
1775 | ||
1776 | uart6850= [HW,OSS] | |
1777 | Format: <io>,<irq> | |
1778 | ||
5f8364b7 AS |
1779 | uhci-hcd.ignore_oc= |
1780 | [USB] Ignore overcurrent events (default N). | |
1781 | Some badly-designed motherboards generate lots of | |
1782 | bogus events, for ports that aren't wired to | |
1783 | anything. Set this parameter to avoid log spamming. | |
1784 | Note that genuine overcurrent events won't be | |
1785 | reported either. | |
1786 | ||
b5e795f8 AS |
1787 | usbcore.autosuspend= |
1788 | [USB] The autosuspend time delay (in seconds) used | |
1789 | for newly-detected USB devices (default 2). This | |
1790 | is the time required before an idle device will be | |
1791 | autosuspended. Devices for which the delay is set | |
1792 | to 0 won't be autosuspended at all. | |
1793 | ||
1da177e4 LT |
1794 | usbhid.mousepoll= |
1795 | [USBHID] The interval which mice are to be polled at. | |
a9913044 | 1796 | |
e523d93c | 1797 | vdso= [IA-32,SH] |
e6e5494c IM |
1798 | vdso=1: enable VDSO (default) |
1799 | vdso=0: disable VDSO mapping | |
1800 | ||
1da177e4 LT |
1801 | video= [FB] Frame buffer configuration |
1802 | See Documentation/fb/modedb.txt. | |
1803 | ||
1804 | vga= [BOOT,IA-32] Select a particular video mode | |
a9913044 RD |
1805 | See Documentation/i386/boot.txt and |
1806 | Documentation/svga.txt. | |
1da177e4 LT |
1807 | Use vga=ask for menu. |
1808 | This is actually a boot loader parameter; the value is | |
1809 | passed to the kernel using a special protocol. | |
1810 | ||
a9913044 | 1811 | vmalloc=nn[KMG] [KNL,BOOT] Forces the vmalloc area to have an exact |
1da177e4 LT |
1812 | size of <nn>. This can be used to increase the |
1813 | minimum size (128MB on x86). It can also be used to | |
1814 | decrease the size and leave more room for directly | |
1815 | mapped kernel RAM. | |
1816 | ||
585c3047 PO |
1817 | vmhalt= [KNL,S390] Perform z/VM CP command after system halt. |
1818 | Format: <command> | |
1da177e4 | 1819 | |
585c3047 PO |
1820 | vmpanic= [KNL,S390] Perform z/VM CP command after kernel panic. |
1821 | Format: <command> | |
1822 | ||
1823 | vmpoff= [KNL,S390] Perform z/VM CP command after power off. | |
1824 | Format: <command> | |
a9913044 | 1825 | |
1da177e4 LT |
1826 | waveartist= [HW,OSS] |
1827 | Format: <io>,<irq>,<dma>,<dma2> | |
a9913044 | 1828 | |
1da177e4 LT |
1829 | wd33c93= [HW,SCSI] |
1830 | See header of drivers/scsi/wd33c93.c. | |
1831 | ||
1832 | wd7000= [HW,SCSI] | |
1833 | See header of drivers/scsi/wd7000.c. | |
1834 | ||
1835 | wdt= [WDT] Watchdog | |
1836 | See Documentation/watchdog/watchdog.txt. | |
1837 | ||
1838 | xd= [HW,XT] Original XT pre-IDE (RLL encoded) disks. | |
1839 | xd_geo= See header of drivers/block/xd.c. | |
1840 | ||
1841 | xirc2ps_cs= [NET,PCMCIA] | |
a9913044 RD |
1842 | Format: |
1843 | <irq>,<irq_mask>,<io>,<full_duplex>,<do_sound>,<lockup_hack>[,<irq2>[,<irq3>[,<irq4>]]] | |
1da177e4 | 1844 | |
a62eaf15 AK |
1845 | norandmaps Don't use address space randomization |
1846 | Equivalent to echo 0 > /proc/sys/kernel/randomize_va_space | |
1847 | ||
6d0185ea JB |
1848 | unwind_debug=N N > 0 will enable dwarf2 unwinder debugging |
1849 | This is useful to get more information why | |
1850 | you got a "dwarf2 unwinder stuck" | |
1da177e4 | 1851 | |
a9913044 | 1852 | ______________________________________________________________________ |
1da177e4 LT |
1853 | |
1854 | TODO: | |
1855 | ||
1856 | Add documentation for ALSA options. | |
1857 | Add more DRM drivers. |