[PATCH] x86: Disable MMCONFIG on Intel SDV using DMI blacklist
[deliverable/linux.git] / Documentation / kernel-parameters.txt
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0ee9d71f 1 Kernel Parameters
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2 ~~~~~~~~~~~~~~~~~
3
4The 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
7case insensitive manner), and with descriptions where known.
8
9Module parameters for loadable modules are specified only as the
10parameter name with optional '=' and value as appropriate, such as:
11
12 modprobe usbcore blinkenlights=1
13
14Module parameters for modules that are built into the kernel image
15are 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
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20This document may not be entirely up to date and comprehensive. The command
21"modinfo -p ${modulename}" shows a current list of all parameters of a loadable
22module. Loadable modules, after being loaded into the running kernel, also
23reveal their parameters in /sys/module/${modulename}/parameters/. Some of these
24parameters may be changed at runtime by the command
25"echo -n ${value} > /sys/module/${modulename}/parameters/${parm}".
26
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27The parameters listed below are only valid if certain kernel build options were
28enabled and if respective hardware is present. The text in square brackets at
29the beginning of each description states the restrictions within which a
30parameter is applicable:
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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.
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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.
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48 ISAPNP ISA PnP code is enabled.
49 ISDN Appropriate ISDN support is enabled.
50 JOY Appropriate joystick support is enabled.
51 LP Printer support is enabled.
52 LOOP Loopback device support is enabled.
53 M68k M68k architecture is enabled.
54 These options have more detailed description inside of
55 Documentation/m68k/kernel-options.txt.
56 MCA MCA bus support is enabled.
57 MDA MDA console support is enabled.
58 MOUSE Appropriate mouse support is enabled.
309e57df 59 MSI Message Signaled Interrupts (PCI).
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60 MTD MTD support is enabled.
61 NET Appropriate network support is enabled.
62 NUMA NUMA support is enabled.
734efb46 63 GENERIC_TIME The generic timeofday code is enabled.
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64 NFS Appropriate NFS support is enabled.
65 OSS OSS sound support is enabled.
66 PARIDE The ParIDE subsystem is enabled.
67 PARISC The PA-RISC architecture is enabled.
68 PCI PCI bus support is enabled.
69 PCMCIA The PCMCIA subsystem is enabled.
70 PNP Plug & Play support is enabled.
71 PPC PowerPC architecture is enabled.
72 PPT Parallel port support is enabled.
73 PS2 Appropriate PS/2 support is enabled.
74 RAM RAM disk support is enabled.
75 S390 S390 architecture is enabled.
76 SCSI Appropriate SCSI support is enabled.
77 A lot of drivers has their options described inside of
78 Documentation/scsi/.
79 SELINUX SELinux support is enabled.
80 SERIAL Serial support is enabled.
81 SMP The kernel is an SMP kernel.
82 SPARC Sparc architecture is enabled.
a9913044 83 SWSUSP Software suspend is enabled.
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84 TS Appropriate touchscreen support is enabled.
85 USB USB support is enabled.
86 USBHID USB Human Interface Device support is enabled.
87 V4L Video For Linux support is enabled.
88 VGA The VGA console has been enabled.
89 VT Virtual terminal support is enabled.
90 WDT Watchdog support is enabled.
91 XT IBM PC/XT MFM hard disk support is enabled.
92 X86-64 X86-64 architecture is enabled.
93 More X86-64 boot options can be found in
94 Documentation/x86_64/boot-options.txt .
95
96In addition, the following text indicates that the option:
97
98 BUGS= Relates to possible processor bugs on the said processor.
99 KNL Is a kernel start-up parameter.
100 BOOT Is a boot loader parameter.
101
102Parameters denoted with BOOT are actually interpreted by the boot
103loader, and have no meaning to the kernel directly.
104Do not modify the syntax of boot loader parameters without extreme
105need or coordination with <Documentation/i386/boot.txt>.
106
107Note that ALL kernel parameters listed below are CASE SENSITIVE, and that
108a trailing = on the name of any parameter states that that parameter will
109be entered as an environment variable, whereas its absence indicates that
110it will appear as a kernel argument readable via /proc/cmdline by programs
111running once the system is up.
112
113 53c7xx= [HW,SCSI] Amiga SCSI controllers
114 See header of drivers/scsi/53c7xx.c.
115 See also Documentation/scsi/ncr53c7xx.txt.
116
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117 acpi= [HW,ACPI] Advanced Configuration and Power Interface
118 Format: { force | off | ht | strict | noirq }
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119 force -- enable ACPI if default was off
120 off -- disable ACPI if default was on
121 noirq -- do not use ACPI for IRQ routing
122 ht -- run only enough ACPI to enable Hyper Threading
a9913044 123 strict -- Be less tolerant of platforms that are not
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124 strictly ACPI specification compliant.
125
126 See also Documentation/pm.txt, pci=noacpi
127
128 acpi_sleep= [HW,ACPI] Sleep options
129 Format: { s3_bios, s3_mode }
130 See Documentation/power/video.txt
a9913044 131
1da177e4 132 acpi_sci= [HW,ACPI] ACPI System Control Interrupt trigger mode
a9913044 133 Format: { level | edge | high | low }
1da177e4 134
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135 acpi_irq_balance [HW,ACPI]
136 ACPI will balance active IRQs
137 default in APIC mode
1da177e4 138
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139 acpi_irq_nobalance [HW,ACPI]
140 ACPI will not move active IRQs (default)
141 default in PIC mode
1da177e4 142
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143 acpi_irq_pci= [HW,ACPI] If irq_balance, clear listed IRQs for
144 use by PCI
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145 Format: <irq>,<irq>...
146
a9913044 147 acpi_irq_isa= [HW,ACPI] If irq_balance, mark listed IRQs used by ISA
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148 Format: <irq>,<irq>...
149
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150 acpi_os_name= [HW,ACPI] Tell ACPI BIOS the name of the OS
151 Format: To spoof as Windows 98: ="Microsoft Windows"
152
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153 acpi_osi= [HW,ACPI] empty param disables _OSI
154
155 acpi_serialize [HW,ACPI] force serialization of AML methods
156
157 acpi_skip_timer_override [HW,ACPI]
158 Recognize and ignore IRQ0/pin2 Interrupt Override.
159 For broken nForce2 BIOS resulting in XT-PIC timer.
160
161 acpi_dbg_layer= [HW,ACPI]
162 Format: <int>
a9913044 163 Each bit of the <int> indicates an ACPI debug layer,
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164 1: enable, 0: disable. It is useful for boot time
165 debugging. After system has booted up, it can be set
166 via /proc/acpi/debug_layer.
167
168 acpi_dbg_level= [HW,ACPI]
169 Format: <int>
a9913044 170 Each bit of the <int> indicates an ACPI debug level,
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171 1: enable, 0: disable. It is useful for boot time
172 debugging. After system has booted up, it can be set
173 via /proc/acpi/debug_level.
174
175 acpi_fake_ecdt [HW,ACPI] Workaround failure due to BIOS lacking ECDT
176
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177 acpi_generic_hotkey [HW,ACPI]
178 Allow consolidated generic hotkey driver to
a9913044 179 override platform specific driver.
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180 See also Documentation/acpi-hotkey.txt.
181
5d0cf410 182 acpi_pm_good [IA-32,X86-64]
183 Override the pmtimer bug detection: force the kernel
184 to assume that this machine's pmtimer latches its value
185 and always returns good values.
186
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187 enable_timer_pin_1 [i386,x86-64]
188 Enable PIN 1 of APIC timer
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189 Can be useful to work around chipset bugs
190 (in particular on some ATI chipsets).
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191 The kernel tries to set a reasonable default.
192
193 disable_timer_pin_1 [i386,x86-64]
194 Disable PIN 1 of APIC timer
195 Can be useful to work around chipset bugs.
196
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197 ad1816= [HW,OSS]
198 Format: <io>,<irq>,<dma>,<dma2>
199 See also Documentation/sound/oss/AD1816.
200
201 ad1848= [HW,OSS]
202 Format: <io>,<irq>,<dma>,<dma2>,<type>
203
204 adlib= [HW,OSS]
205 Format: <io>
a9913044 206
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207 advansys= [HW,SCSI]
208 See header of drivers/scsi/advansys.c.
209
210 advwdt= [HW,WDT] Advantech WDT
211 Format: <iostart>,<iostop>
212
213 aedsp16= [HW,OSS] Audio Excel DSP 16
214 Format: <io>,<irq>,<dma>,<mss_io>,<mpu_io>,<mpu_irq>
215 See also header of sound/oss/aedsp16.c.
a9913044 216
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217 aha152x= [HW,SCSI]
218 See Documentation/scsi/aha152x.txt.
219
220 aha1542= [HW,SCSI]
221 Format: <portbase>[,<buson>,<busoff>[,<dmaspeed>]]
222
223 aic7xxx= [HW,SCSI]
224 See Documentation/scsi/aic7xxx.txt.
225
226 aic79xx= [HW,SCSI]
227 See Documentation/scsi/aic79xx.txt.
228
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229 amijoy.map= [HW,JOY] Amiga joystick support
230 Map of devices attached to JOY0DAT and JOY1DAT
231 Format: <a>,<b>
232 See also Documentation/kernel/input/joystick.txt
233
234 analog.map= [HW,JOY] Analog joystick and gamepad support
235 Specifies type or capabilities of an analog joystick
236 connected to one of 16 gameports
237 Format: <type1>,<type2>,..<type16>
238
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239 apc= [HW,SPARC]
240 Power management functions (SPARCstation-4/5 + deriv.)
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241 Format: noidle
242 Disable APC CPU standby support. SPARCstation-Fox does
243 not play well with APC CPU idle - disable it if you have
244 APC and your system crashes randomly.
245
a9913044 246 apic= [APIC,i386] Change the output verbosity whilst booting
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247 Format: { quiet (default) | verbose | debug }
248 Change the amount of debugging information output
249 when initialising the APIC and IO-APIC components.
a9913044 250
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251 apm= [APM] Advanced Power Management
252 See header of arch/i386/kernel/apm.c.
253
254 applicom= [HW]
255 Format: <mem>,<irq>
a9913044 256
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257 arcrimi= [HW,NET] ARCnet - "RIM I" (entirely mem-mapped) cards
258 Format: <io>,<irq>,<nodeID>
259
260 ataflop= [HW,M68k]
261
262 atarimouse= [HW,MOUSE] Atari Mouse
263
264 atascsi= [HW,SCSI] Atari SCSI
265
266 atkbd.extra= [HW] Enable extra LEDs and keys on IBM RapidAccess,
267 EzKey and similar keyboards
268
269 atkbd.reset= [HW] Reset keyboard during initialization
270
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271 atkbd.set= [HW] Select keyboard code set
272 Format: <int> (2 = AT (default), 3 = PS/2)
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273
274 atkbd.scroll= [HW] Enable scroll wheel on MS Office and similar
275 keyboards
276
277 atkbd.softraw= [HW] Choose between synthetic and real raw mode
278 Format: <bool> (0 = real, 1 = synthetic (default))
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279
280 atkbd.softrepeat= [HW]
281 Use software keyboard repeat
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282
283 autotest [IA64]
284
285 awe= [HW,OSS] AWE32/SB32/AWE64 wave table synth
286 Format: <io>,<memsize>,<isapnp>
a9913044 287
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288 aztcd= [HW,CD] Aztech CD268 CDROM driver
289 Format: <io>,0x79 (?)
290
291 baycom_epp= [HW,AX25]
292 Format: <io>,<mode>
a9913044 293
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294 baycom_par= [HW,AX25] BayCom Parallel Port AX.25 Modem
295 Format: <io>,<mode>
296 See header of drivers/net/hamradio/baycom_par.c.
297
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298 baycom_ser_fdx= [HW,AX25]
299 BayCom Serial Port AX.25 Modem (Full Duplex Mode)
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300 Format: <io>,<irq>,<mode>[,<baud>]
301 See header of drivers/net/hamradio/baycom_ser_fdx.c.
302
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303 baycom_ser_hdx= [HW,AX25]
304 BayCom Serial Port AX.25 Modem (Half Duplex Mode)
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305 Format: <io>,<irq>,<mode>
306 See header of drivers/net/hamradio/baycom_ser_hdx.c.
307
308 blkmtd_device= [HW,MTD]
309 blkmtd_erasesz=
310 blkmtd_ro=
311 blkmtd_bs=
312 blkmtd_count=
313
314 bttv.card= [HW,V4L] bttv (bt848 + bt878 based grabber cards)
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315 bttv.radio= Most important insmod options are available as
316 kernel args too.
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317 bttv.pll= See Documentation/video4linux/bttv/Insmod-options
318 bttv.tuner= and Documentation/video4linux/bttv/CARDLIST
319
320 BusLogic= [HW,SCSI]
321 See drivers/scsi/BusLogic.c, comment before function
322 BusLogic_ParseDriverOptions().
323
324 c101= [NET] Moxa C101 synchronous serial card
325
326 cachesize= [BUGS=IA-32] Override level 2 CPU cache size detection.
327 Sometimes CPU hardware bugs make them report the cache
328 size incorrectly. The kernel will attempt work arounds
329 to fix known problems, but for some CPUs it is not
330 possible to determine what the correct size should be.
331 This option provides an override for these situations.
332
333 cdu31a= [HW,CD]
334 Format: <io>,<irq>[,PAS]
335 See header of drivers/cdrom/cdu31a.c.
336
337 chandev= [HW,NET] Generic channel device initialisation
338
339 checkreqprot [SELINUX] Set initial checkreqprot flag value.
340 Format: { "0" | "1" }
341 See security/selinux/Kconfig help text.
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342 0 -- check protection applied by kernel (includes
343 any implied execute protection).
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344 1 -- check protection requested by application.
345 Default value is set via a kernel config option.
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346 Value can be changed at runtime via
347 /selinux/checkreqprot.
348
734efb46 349 clock= [BUGS=IA-32, HW] gettimeofday clocksource override.
350 [Deprecated]
351 Forces specified clocksource (if avaliable) to be used
352 when calculating gettimeofday(). If specified
353 clocksource is not avalible, it defaults to PIT.
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354 Format: { pit | tsc | cyclone | pmtmr }
355
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356 disable_8254_timer
357 enable_8254_timer
358 [IA32/X86_64] Disable/Enable interrupt 0 timer routing
359 over the 8254 in addition to over the IO-APIC. The
360 kernel tries to set a sensible default.
361
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362 hpet= [IA-32,HPET] option to disable HPET and use PIT.
363 Format: disable
364
365 cm206= [HW,CD]
366 Format: { auto | [<io>,][<irq>] }
367
368 com20020= [HW,NET] ARCnet - COM20020 chipset
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369 Format:
370 <io>[,<irq>[,<nodeID>[,<backplane>[,<ckp>[,<timeout>]]]]]
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371
372 com90io= [HW,NET] ARCnet - COM90xx chipset (IO-mapped buffers)
373 Format: <io>[,<irq>]
374
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375 com90xx= [HW,NET]
376 ARCnet - COM90xx chipset (memory-mapped buffers)
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377 Format: <io>[,<irq>[,<memstart>]]
378
379 condev= [HW,S390] console device
380 conmode=
a9913044 381
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382 console= [KNL] Output console device and options.
383
384 tty<n> Use the virtual console device <n>.
385
386 ttyS<n>[,options]
f1a1c2dc 387 ttyUSB0[,options]
1da177e4 388 Use the specified serial port. The options are of
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389 the form "bbbbpnf", where "bbbb" is the baud rate,
390 "p" is parity ("n", "o", or "e"), "n" is number of
391 bits, and "f" is flow control ("r" for RTS or
392 omit it). Default is "9600n8".
393
394 See Documentation/serial-console.txt for more
395 information. See
396 Documentation/networking/netconsole.txt for an
397 alternative.
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398
399 uart,io,<addr>[,options]
400 uart,mmio,<addr>[,options]
401 Start an early, polled-mode console on the 8250/16550
402 UART at the specified I/O port or MMIO address,
403 switching to the matching ttyS device later. The
404 options are the same as for ttyS, above.
405
406 cpcihp_generic= [HW,PCI] Generic port I/O CompactPCI driver
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407 Format:
408 <first_slot>,<last_slot>,<port>,<enum_bit>[,<debug>]
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409
410 cpia_pp= [HW,PPT]
411 Format: { parport<nr> | auto | none }
412
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413 crashkernel=nn[KMG]@ss[KMG]
414 [KNL] Reserve a chunk of physical memory to
415 hold a kernel to switch to with kexec on panic.
416
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417 cs4232= [HW,OSS]
418 Format: <io>,<irq>,<dma>,<dma2>,<mpuio>,<mpuirq>
419
420 cs89x0_dma= [HW,NET]
421 Format: <dma>
422
423 cs89x0_media= [HW,NET]
424 Format: { rj45 | aui | bnc }
a9913044 425
1da177e4 426 cyclades= [HW,SERIAL] Cyclades multi-serial port adapter.
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427
428 dasd= [HW,NET]
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429 See header of drivers/s390/block/dasd_devmap.c.
430
431 db9.dev[2|3]= [HW,JOY] Multisystem joystick support via parallel port
432 (one device per port)
433 Format: <port#>,<type>
434 See also Documentation/input/joystick-parport.txt
435
436 debug [KNL] Enable kernel debugging (events log level).
437
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438 debug_locks_verbose=
439 [KNL] verbose self-tests
440 Format=<0|1>
441 Print debugging info while doing the locking API
442 self-tests.
443 We default to 0 (no extra messages), setting it to
444 1 will print _a lot_ more information - normally
445 only useful to kernel developers.
446
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447 decnet= [HW,NET]
448 Format: <area>[,<node>]
449 See also Documentation/networking/decnet.txt.
450
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451 dhash_entries= [KNL]
452 Set number of hash buckets for dentry cache.
a9913044 453
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454 digi= [HW,SERIAL]
455 IO parameters + enable/disable command.
456
457 digiepca= [HW,SERIAL]
458 See drivers/char/README.epca and
459 Documentation/digiepca.txt.
460
461 dmascc= [HW,AX25,SERIAL] AX.25 Z80SCC driver with DMA
462 support available.
463 Format: <io_dev0>[,<io_dev1>[,..<io_dev32>]]
464
465 dmasound= [HW,OSS] Sound subsystem buffers
466
467 dscc4.setup= [NET]
468
469 dtc3181e= [HW,SCSI]
470
a9913044 471 earlyprintk= [IA-32,X86-64]
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472 earlyprintk=vga
473 earlyprintk=serial[,ttySn[,baudrate]]
474
a9913044 475 Append ",keep" to not disable it when the real console
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476 takes over.
477
478 Only vga or serial at a time, not both.
479
480 Currently only ttyS0 and ttyS1 are supported.
481
482 Interaction with the standard serial driver is not
483 very good.
484
485 The VGA output is eventually overwritten by the real
486 console.
487
488 eata= [HW,SCSI]
489
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490 ec_intr= [HW,ACPI] ACPI Embedded Controller interrupt mode
491 Format: <int>
492 0: polling mode
493 non-0: interrupt mode (default)
494
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495 eda= [HW,PS2]
496
497 edb= [HW,PS2]
498
499 edd= [EDD]
500 Format: {"of[f]" | "sk[ipmbr]"}
501 See comment in arch/i386/boot/edd.S
502
a9913044 503 eicon= [HW,ISDN]
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504 Format: <id>,<membase>,<irq>
505
506 eisa_irq_edge= [PARISC,HW]
507 See header of drivers/parisc/eisa.c.
508
509 elanfreq= [IA-32]
510 See comment before function elanfreq_setup() in
511 arch/i386/kernel/cpu/cpufreq/elanfreq.c.
512
513 elevator= [IOSCHED]
16ab3adf 514 Format: {"anticipatory" | "cfq" | "deadline" | "noop"}
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515 See Documentation/block/as-iosched.txt and
516 Documentation/block/deadline-iosched.txt for details.
517
aac04b32 518 elfcorehdr= [IA-32, X86_64]
a9913044 519 Specifies physical address of start of kernel core
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520 image elf header. Generally kexec loader will
521 pass this option to capture kernel.
522 See Documentation/kdump/kdump.txt for details.
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523
524 enforcing [SELINUX] Set initial enforcing status.
525 Format: {"0" | "1"}
526 See security/selinux/Kconfig help text.
527 0 -- permissive (log only, no denials).
528 1 -- enforcing (deny and log).
529 Default value is 0.
530 Value can be changed at runtime via /selinux/enforce.
531
532 es1370= [HW,OSS]
533 Format: <lineout>[,<micbias>]
534 See also header of sound/oss/es1370.c.
535
536 es1371= [HW,OSS]
537 Format: <spdif>,[<nomix>,[<amplifier>]]
538 See also header of sound/oss/es1371.c.
a9913044 539
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540 ether= [HW,NET] Ethernet cards parameters
541 This option is obsoleted by the "netdev=" option, which
542 has equivalent usage. See its documentation for details.
543
544 eurwdt= [HW,WDT] Eurotech CPU-1220/1410 onboard watchdog.
545 Format: <io>[,<irq>]
546
547 fd_mcs= [HW,SCSI]
548 See header of drivers/scsi/fd_mcs.c.
549
550 fdomain= [HW,SCSI]
551 See header of drivers/scsi/fdomain.c.
552
553 floppy= [HW]
554 See Documentation/floppy.txt.
555
556 ftape= [HW] Floppy Tape subsystem debugging options.
557 See Documentation/ftape.txt.
558
559 gamecon.map[2|3]=
560 [HW,JOY] Multisystem joystick and NES/SNES/PSX pad
561 support via parallel port (up to 5 devices per port)
562 Format: <port#>,<pad1>,<pad2>,<pad3>,<pad4>,<pad5>
563 See also Documentation/input/joystick-parport.txt
564
565 gamma= [HW,DRM]
566
567 gdth= [HW,SCSI]
568 See header of drivers/scsi/gdth.c.
569
570 gpt [EFI] Forces disk with valid GPT signature but
571 invalid Protective MBR to be treated as GPT.
572
573 gscd= [HW,CD]
574 Format: <io>
575
576 gt96100eth= [NET] MIPS GT96100 Advanced Communication Controller
577
578 gus= [HW,OSS]
579 Format: <io>,<irq>,<dma>,<dma16>
a9913044 580
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581 gvp11= [HW,SCSI]
582
583 hashdist= [KNL,NUMA] Large hashes allocated during boot
584 are distributed across NUMA nodes. Defaults on
585 for IA-64, off otherwise.
a9913044 586 Format: 0 | 1 (for off | on)
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587
588 hcl= [IA-64] SGI's Hardware Graph compatibility layer
589
590 hd= [EIDE] (E)IDE hard drive subsystem geometry
591 Format: <cyl>,<head>,<sect>
592
593 hd?= [HW] (E)IDE subsystem
594 hd?lun= See Documentation/ide.txt.
595
596 highmem=nn[KMG] [KNL,BOOT] forces the highmem zone to have an exact
597 size of <nn>. This works even on boxes that have no
598 highmem otherwise. This also works to reduce highmem
599 size on bigger boxes.
600
601 hisax= [HW,ISDN]
602 See Documentation/isdn/README.HiSax.
603
604 hugepages= [HW,IA-32,IA-64] Maximal number of HugeTLB pages.
605
606 noirqbalance [IA-32,SMP,KNL] Disable kernel irq balancing
607
608 i8042.direct [HW] Put keyboard port into non-translated mode
609 i8042.dumbkbd [HW] Pretend that controlled can only read data from
610 keyboard and can not control its state
611 (Don't attempt to blink the leds)
612 i8042.noaux [HW] Don't check for auxiliary (== mouse) port
945ef0d4 613 i8042.nokbd [HW] Don't check/create keyboard port
1da177e4
LT
614 i8042.nomux [HW] Don't check presence of an active multiplexing
615 controller
616 i8042.nopnp [HW] Don't use ACPIPnP / PnPBIOS to discover KBD/AUX
617 controllers
618 i8042.panicblink=
619 [HW] Frequency with which keyboard LEDs should blink
620 when kernel panics (default is 0.5 sec)
621 i8042.reset [HW] Reset the controller during init and cleanup
622 i8042.unlock [HW] Unlock (ignore) the keylock
623
624 i810= [HW,DRM]
625
e70c9d5e
DT
626 i8k.ignore_dmi [HW] Continue probing hardware even if DMI data
627 indicates that the driver is running on unsupported
628 hardware.
1da177e4
LT
629 i8k.force [HW] Activate i8k driver even if SMM BIOS signature
630 does not match list of supported models.
631 i8k.power_status
632 [HW] Report power status in /proc/i8k
633 (disabled by default)
634 i8k.restricted [HW] Allow controlling fans only if SYS_ADMIN
635 capability is set.
636
637 ibmmcascsi= [HW,MCA,SCSI] IBM MicroChannel SCSI adapter
638 See Documentation/mca.txt.
639
640 icn= [HW,ISDN]
641 Format: <io>[,<membase>[,<icn_id>[,<icn_id2>]]]
642
643 ide= [HW] (E)IDE subsystem
644 Format: ide=nodma or ide=doubler or ide=reverse
645 See Documentation/ide.txt.
646
647 ide?= [HW] (E)IDE subsystem
648 Format: ide?=noprobe or chipset specific parameters.
649 See Documentation/ide.txt.
a9913044 650
1da177e4
LT
651 idebus= [HW] (E)IDE subsystem - VLB/PCI bus speed
652 See Documentation/ide.txt.
653
654 idle= [HW]
655 Format: idle=poll or idle=halt
a9913044 656
1da177e4
LT
657 ihash_entries= [KNL]
658 Set number of hash buckets for inode cache.
659
660 in2000= [HW,SCSI]
661 See header of drivers/scsi/in2000.c.
662
663 init= [KNL]
664 Format: <full_path>
665 Run specified binary instead of /sbin/init as init
666 process.
667
668 initcall_debug [KNL] Trace initcalls as they are executed. Useful
669 for working out where the kernel is dying during
670 startup.
671
672 initrd= [BOOT] Specify the location of the initial ramdisk
673
674 inport.irq= [HW] Inport (ATI XL and Microsoft) busmouse driver
675 Format: <irq>
676
2bd0fa3b
JB
677 combined_mode= [HW] control which driver uses IDE ports in combined
678 mode: legacy IDE driver, libata, or both
679 (in the libata case, libata.atapi_enabled=1 may be
680 useful as well). Note that using the ide or libata
681 options may affect your device naming (e.g. by
682 changing hdc to sdb).
683 Format: combined (default), ide, or libata
684
1da177e4
LT
685 inttest= [IA64]
686
687 io7= [HW] IO7 for Marvel based alpha systems
688 See comment before marvel_specify_io7 in
689 arch/alpha/kernel/core_marvel.c.
690
691 ip= [IP_PNP]
692 See Documentation/nfsroot.txt.
693
694 ip2= [HW] Set IO/IRQ pairs for up to 4 IntelliPort boards
695 See comment before ip2_setup() in drivers/char/ip2.c.
696
697 ips= [HW,SCSI] Adaptec / IBM ServeRAID controller
698 See header of drivers/scsi/ips.c.
699
200803df
AC
700 irqfixup [HW]
701 When an interrupt is not handled search all handlers
702 for it. Intended to get systems with badly broken
703 firmware running.
704
705 irqpoll [HW]
706 When an interrupt is not handled search all handlers
707 for it. Also check all handlers each timer
708 interrupt. Intended to get systems with badly broken
709 firmware running.
710
1da177e4 711 isapnp= [ISAPNP]
a9913044 712 Format: <RDP>,<reset>,<pci_scan>,<verbosity>
1da177e4
LT
713
714 isolcpus= [KNL,SMP] Isolate CPUs from the general scheduler.
715 Format: <cpu number>,...,<cpu number>
716 This option can be used to specify one or more CPUs
717 to isolate from the general SMP balancing and scheduling
718 algorithms. The only way to move a process onto or off
719 an "isolated" CPU is via the CPU affinity syscalls.
720 <cpu number> begins at 0 and the maximum value is
721 "number of CPUs in system - 1".
722
723 This option is the preferred way to isolate CPUs. The
a9913044
RD
724 alternative -- manually setting the CPU mask of all
725 tasks in the system -- can cause problems and
726 suboptimal load balancer performance.
1da177e4
LT
727
728 isp16= [HW,CD]
729 Format: <io>,<irq>,<dma>,<setup>
730
a9913044 731 iucv= [HW,NET]
1da177e4
LT
732
733 js= [HW,JOY] Analog joystick
734 See Documentation/input/joystick.txt.
735
736 keepinitrd [HW,ARM]
737
a9913044 738 kstack=N [IA-32,X86-64] Print N words from the kernel stack
1da177e4
LT
739 in oops dumps.
740
741 l2cr= [PPC]
742
a9913044
RD
743 lapic [IA-32,APIC] Enable the local APIC even if BIOS
744 disabled it.
1da177e4
LT
745
746 lasi= [HW,SCSI] PARISC LASI driver for the 53c700 chip
747 Format: addr:<io>,irq:<irq>
748
a9913044
RD
749 llsc*= [IA64] See function print_params() in
750 arch/ia64/sn/kernel/llsc4.c.
1da177e4
LT
751
752 load_ramdisk= [RAM] List of ramdisks to load from floppy
753 See Documentation/ramdisk.txt.
754
a6b25b67
RD
755 lockd.nlm_grace_period=P [NFS] Assign grace period.
756 Format: <integer>
1da177e4 757
a6b25b67
RD
758 lockd.nlm_tcpport=N [NFS] Assign TCP port.
759 Format: <integer>
760
761 lockd.nlm_timeout=T [NFS] Assign timeout value.
762 Format: <integer>
763
764 lockd.nlm_udpport=M [NFS] Assign UDP port.
765 Format: <integer>
1da177e4
LT
766
767 logibm.irq= [HW,MOUSE] Logitech Bus Mouse Driver
768 Format: <irq>
769
770 loglevel= All Kernel Messages with a loglevel smaller than the
771 console loglevel will be printed to the console. It can
772 also be changed with klogd or other programs. The
773 loglevels are defined as follows:
774
775 0 (KERN_EMERG) system is unusable
776 1 (KERN_ALERT) action must be taken immediately
777 2 (KERN_CRIT) critical conditions
778 3 (KERN_ERR) error conditions
779 4 (KERN_WARNING) warning conditions
780 5 (KERN_NOTICE) normal but significant condition
781 6 (KERN_INFO) informational
782 7 (KERN_DEBUG) debug-level messages
783
784 log_buf_len=n Sets the size of the printk ring buffer, in bytes.
a9913044
RD
785 Format: { n | nk | nM }
786 n must be a power of two. The default size
787 is set in the kernel config file.
1da177e4
LT
788
789 lp=0 [LP] Specify parallel ports to use, e.g,
790 lp=port[,port...] lp=none,parport0 (lp0 not configured, lp1 uses
791 lp=reset first parallel port). 'lp=0' disables the
792 lp=auto printer driver. 'lp=reset' (which can be
793 specified in addition to the ports) causes
794 attached printers to be reset. Using
795 lp=port1,port2,... specifies the parallel ports
796 to associate lp devices with, starting with
797 lp0. A port specification may be 'none' to skip
798 that lp device, or a parport name such as
799 'parport0'. Specifying 'lp=auto' instead of a
800 port specification list means that device IDs
801 from each port should be examined, to see if
802 an IEEE 1284-compliant printer is attached; if
803 so, the driver will manage that printer.
804 See also header of drivers/char/lp.c.
805
806 lpj=n [KNL]
807 Sets loops_per_jiffy to given constant, thus avoiding
808 time-consuming boot-time autodetection (up to 250 ms per
809 CPU). 0 enables autodetection (default). To determine
810 the correct value for your kernel, boot with normal
811 autodetection and see what value is printed. Note that
812 on SMP systems the preset will be applied to all CPUs,
813 which is likely to cause problems if your CPUs need
814 significantly divergent settings. An incorrect value
815 will cause delays in the kernel to be wrong, leading to
816 unpredictable I/O errors and other breakage. Although
817 unlikely, in the extreme case this might damage your
818 hardware.
819
820 ltpc= [NET]
821 Format: <io>,<irq>,<dma>
822
a9913044
RD
823 mac5380= [HW,SCSI] Format:
824 <can_queue>,<cmd_per_lun>,<sg_tablesize>,<hostid>,<use_tags>
1da177e4 825
a9913044
RD
826 mac53c9x= [HW,SCSI] Format:
827 <num_esps>,<disconnect>,<nosync>,<can_queue>,<cmd_per_lun>,<sg_tablesize>,<hostid>,<use_tags>
1da177e4 828
a9913044
RD
829 machvec= [IA64] Force the use of a particular machine-vector
830 (machvec) in a generic kernel.
831 Example: machvec=hpzx1_swiotlb
1da177e4 832
a9913044
RD
833 mad16= [HW,OSS] Format:
834 <io>,<irq>,<dma>,<dma16>,<mpu_io>,<mpu_irq>,<joystick>
1da177e4
LT
835
836 maui= [HW,OSS]
837 Format: <io>,<irq>
a9913044
RD
838
839 max_loop= [LOOP] Maximum number of loopback devices that can
1da177e4
LT
840 be mounted
841 Format: <1-256>
842
843 maxcpus= [SMP] Maximum number of processors that an SMP kernel
844 should make use of
845
2b2c3750
BP
846 max_addr=[KMG] [KNL,BOOT,ia64] All physical memory greater than or
847 equal to this physical address is ignored.
848
a9913044 849 max_luns= [SCSI] Maximum number of LUNs to probe.
1da177e4
LT
850 Should be between 1 and 2^32-1.
851
852 max_report_luns=
a9913044 853 [SCSI] Maximum number of LUNs received.
1da177e4
LT
854 Should be between 1 and 16384.
855
856 mca-pentium [BUGS=IA-32]
857
858 mcatest= [IA-64]
859
860 mcd= [HW,CD]
861 Format: <port>,<irq>,<mitsumi_bug_93_wait>
862
863 mcdx= [HW,CD]
864
865 mce [IA-32] Machine Check Exception
866
867 md= [HW] RAID subsystems devices and level
868 See Documentation/md.txt.
a9913044 869
1da177e4
LT
870 mdacon= [MDA]
871 Format: <first>,<last>
872 Specifies range of consoles to be captured by the MDA.
a9913044 873
1da177e4
LT
874 mem=nn[KMG] [KNL,BOOT] Force usage of a specific amount of memory
875 Amount of memory to be used when the kernel is not able
876 to see the whole system memory or for test.
877 [IA-32] Use together with memmap= to avoid physical
878 address space collisions. Without memmap= PCI devices
879 could be placed at addresses belonging to unused RAM.
880
881 mem=nopentium [BUGS=IA-32] Disable usage of 4MB pages for kernel
882 memory.
883
69cda7b1 884 memmap=exactmap [KNL,IA-32,X86_64] Enable setting of an exact
1da177e4
LT
885 E820 memory map, as specified by the user.
886 Such memmap=exactmap lines can be constructed based on
887 BIOS output or other requirements. See the memmap=nn@ss
888 option description.
889
890 memmap=nn[KMG]@ss[KMG]
891 [KNL] Force usage of a specific region of memory
892 Region of memory to be used, from ss to ss+nn.
893
894 memmap=nn[KMG]#ss[KMG]
895 [KNL,ACPI] Mark specific memory as ACPI data.
896 Region of memory to be used, from ss to ss+nn.
897
898 memmap=nn[KMG]$ss[KMG]
899 [KNL,ACPI] Mark specific memory as reserved.
900 Region of memory to be used, from ss to ss+nn.
901
902 meye.*= [HW] Set MotionEye Camera parameters
903 See Documentation/video4linux/meye.txt.
904
905 mga= [HW,DRM]
906
198e2f18 907 migration_cost=
908 [KNL,SMP] debug: override scheduler migration costs
909 Format: <level-1-usecs>,<level-2-usecs>,...
910 This debugging option can be used to override the
911 default scheduler migration cost matrix. The numbers
912 are indexed by 'CPU domain distance'.
913 E.g. migration_cost=1000,2000,3000 on an SMT NUMA
914 box will set up an intra-core migration cost of
915 1 msec, an inter-core migration cost of 2 msecs,
916 and an inter-node migration cost of 3 msecs.
917
918 WARNING: using the wrong values here can break
919 scheduler performance, so it's only for scheduler
920 development purposes, not production environments.
921
922 migration_debug=
923 [KNL,SMP] migration cost auto-detect verbosity
924 Format=<0|1|2>
925 If a system's migration matrix reported at bootup
926 seems erroneous then this option can be used to
927 increase verbosity of the detection process.
928 We default to 0 (no extra messages), 1 will print
929 some more information, and 2 will be really
930 verbose (probably only useful if you also have a
931 serial console attached to the system).
932
933 migration_factor=
934 [KNL,SMP] multiply/divide migration costs by a factor
935 Format=<percent>
936 This debug option can be used to proportionally
937 increase or decrease the auto-detected migration
938 costs for all entries of the migration matrix.
939 E.g. migration_factor=150 will increase migration
940 costs by 50%. (and thus the scheduler will be less
941 eager migrating cache-hot tasks)
942 migration_factor=80 will decrease migration costs
943 by 20%. (thus the scheduler will be more eager to
944 migrate tasks)
945
946 WARNING: using the wrong values here can break
947 scheduler performance, so it's only for scheduler
948 development purposes, not production environments.
949
1da177e4
LT
950 mousedev.tap_time=
951 [MOUSE] Maximum time between finger touching and
952 leaving touchpad surface for touch to be considered
953 a tap and be reported as a left button click (for
954 touchpads working in absolute mode only).
955 Format: <msecs>
956 mousedev.xres= [MOUSE] Horizontal screen resolution, used for devices
957 reporting absolute coordinates, such as tablets
958 mousedev.yres= [MOUSE] Vertical screen resolution, used for devices
959 reporting absolute coordinates, such as tablets
960
961 mpu401= [HW,OSS]
962 Format: <io>,<irq>
963
964 MTD_Partition= [MTD]
965 Format: <name>,<region-number>,<size>,<offset>
966
a9913044
RD
967 MTD_Region= [MTD] Format:
968 <name>,<region-number>[,<base>,<size>,<buswidth>,<altbuswidth>]
1da177e4
LT
969
970 mtdparts= [MTD]
971 See drivers/mtd/cmdline.c.
972
973 mtouchusb.raw_coordinates=
a9913044
RD
974 [HW] Make the MicroTouch USB driver use raw coordinates
975 ('y', default) or cooked coordinates ('n')
1da177e4
LT
976
977 n2= [NET] SDL Inc. RISCom/N2 synchronous serial card
978
979 NCR_D700= [HW,SCSI]
980 See header of drivers/scsi/NCR_D700.c.
981
982 ncr5380= [HW,SCSI]
983
984 ncr53c400= [HW,SCSI]
985
986 ncr53c400a= [HW,SCSI]
987
988 ncr53c406a= [HW,SCSI]
989
990 ncr53c8xx= [HW,SCSI]
991
992 netdev= [NET] Network devices parameters
993 Format: <irq>,<io>,<mem_start>,<mem_end>,<name>
994 Note that mem_start is often overloaded to mean
995 something different and driver-specific.
a9913044
RD
996 This usage is only documented in each driver source
997 file if at all.
998
1da177e4
LT
999 nfsaddrs= [NFS]
1000 See Documentation/nfsroot.txt.
1001
1002 nfsroot= [NFS] nfs root filesystem for disk-less boxes.
1003 See Documentation/nfsroot.txt.
1004
a72b4422
TM
1005 nfs.callback_tcpport=
1006 [NFS] set the TCP port on which the NFSv4 callback
1007 channel should listen.
1008
58df095b
TM
1009 nfs.idmap_cache_timeout=
1010 [NFS] set the maximum lifetime for idmapper cache
1011 entries.
1012
1da177e4
LT
1013 nmi_watchdog= [KNL,BUGS=IA-32] Debugging features for SMP kernels
1014
1015 no387 [BUGS=IA-32] Tells the kernel to use the 387 maths
1016 emulation library even if a 387 maths coprocessor
1017 is present.
1018
a9913044
RD
1019 noalign [KNL,ARM]
1020
1da177e4
LT
1021 noapic [SMP,APIC] Tells the kernel to not make use of any
1022 IOAPICs that may be present in the system.
1023
1024 noasync [HW,M68K] Disables async and sync negotiation for
1025 all devices.
1026
1027 nobats [PPC] Do not use BATs for mapping kernel lowmem
1028 on "Classic" PPC cores.
1029
1030 nocache [ARM]
a9913044 1031
163ecdff
SN
1032 nodelayacct [KNL] Disable per-task delay accounting
1033
1da177e4
LT
1034 nodisconnect [HW,SCSI,M68K] Disables SCSI disconnects.
1035
1036 noexec [IA-64]
1037
a9913044 1038 noexec [IA-32,X86-64]
1da177e4
LT
1039 noexec=on: enable non-executable mappings (default)
1040 noexec=off: disable nn-executable mappings
1041
4f886511
CE
1042 nofxsr [BUGS=IA-32] Disables x86 floating point extended
1043 register save and restore. The kernel will only save
1044 legacy floating-point registers on task switch.
1da177e4
LT
1045
1046 nohlt [BUGS=ARM]
a9913044 1047
1da177e4
LT
1048 no-hlt [BUGS=IA-32] Tells the kernel that the hlt
1049 instruction doesn't work correctly and not to
1050 use it.
1051
1052 nohalt [IA-64] Tells the kernel not to use the power saving
1053 function PAL_HALT_LIGHT when idle. This increases
1054 power-consumption. On the positive side, it reduces
1055 interrupt wake-up latency, which may improve performance
1056 in certain environments such as networked servers or
1057 real-time systems.
1058
1059 noirqdebug [IA-32] Disables the code which attempts to detect and
1060 disable unhandled interrupt sources.
1061
1062 noisapnp [ISAPNP] Disables ISA PnP code.
1063
1064 noinitrd [RAM] Tells the kernel not to load any configured
1065 initial RAM disk.
1066
1067 nointroute [IA-64]
1068
1069 nolapic [IA-32,APIC] Do not enable or use the local APIC.
1070
1071 noltlbs [PPC] Do not use large page/tlb entries for kernel
1072 lowmem mapping on PPC40x.
1073
312f1f01
H
1074 nomca [IA-64] Disable machine check abort handling
1075
abe37e5a
H
1076 nomce [IA-32] Machine Check Exception
1077
1da177e4
LT
1078 noresidual [PPC] Don't use residual data on PReP machines.
1079
a9913044
RD
1080 noresume [SWSUSP] Disables resume and restores original swap
1081 space.
1082
1da177e4
LT
1083 no-scroll [VGA] Disables scrollback.
1084 This is required for the Braillex ib80-piezo Braille
1085 reader made by F.H. Papenmeier (Germany).
1086
1087 nosbagart [IA-64]
1088
4f886511
CE
1089 nosep [BUGS=IA-32] Disables x86 SYSENTER/SYSEXIT support.
1090
1da177e4
LT
1091 nosmp [SMP] Tells an SMP kernel to act as a UP kernel.
1092
1093 nosync [HW,M68K] Disables sync negotiation for all devices.
1094
1095 notsc [BUGS=IA-32] Disable Time Stamp Counter
1096
1097 nousb [USB] Disable the USB subsystem
1098
1099 nowb [ARM]
a9913044 1100
a61c2d78
DJ
1101 nr_uarts= [SERIAL] maximum number of UARTs to be registered.
1102
1da177e4
LT
1103 opl3= [HW,OSS]
1104 Format: <io>
1105
1106 opl3sa= [HW,OSS]
1107 Format: <io>,<irq>,<dma>,<dma2>,<mpu_io>,<mpu_irq>
1108
a9913044
RD
1109 opl3sa2= [HW,OSS] Format:
1110 <io>,<irq>,<dma>,<dma2>,<mss_io>,<mpu_io>,<ymode>,<loopback>[,<isapnp>,<multiple]
1111
1da177e4
LT
1112 oprofile.timer= [HW]
1113 Use timer interrupt instead of performance counters
1114
1115 optcd= [HW,CD]
1116 Format: <io>
1117
1118 osst= [HW,SCSI] SCSI Tape Driver
1119 Format: <buffer_size>,<write_threshold>
1120 See also Documentation/scsi/st.txt.
1121
1122 panic= [KNL] Kernel behaviour on panic
1123 Format: <timeout>
1124
1125 parkbd.port= [HW] Parallel port number the keyboard adapter is
1126 connected to, default is 0.
1127 Format: <parport#>
1128 parkbd.mode= [HW] Parallel port keyboard adapter mode of operation,
1129 0 for XT, 1 for AT (default is AT).
a9913044
RD
1130 Format: <mode>
1131
1132 parport= [HW,PPT] Specify parallel ports. 0 disables.
1133 Format: { 0 | auto | 0xBBB[,IRQ[,DMA]] }
1134 Use 'auto' to force the driver to use any
1135 IRQ/DMA settings detected (the default is to
1136 ignore detected IRQ/DMA settings because of
1137 possible conflicts). You can specify the base
1138 address, IRQ, and DMA settings; IRQ and DMA
1139 should be numbers, or 'auto' (for using detected
1140 settings on that particular port), or 'nofifo'
1141 (to avoid using a FIFO even if it is detected).
1142 Parallel ports are assigned in the order they
1143 are specified on the command line, starting
1144 with parport0.
1145
1146 parport_init_mode= [HW,PPT]
1147 Configure VIA parallel port to operate in
1148 a specific mode. This is necessary on Pegasos
1149 computer where firmware has no options for setting
1150 up parallel port mode and sets it to spp.
1151 Currently this function knows 686a and 8231 chips.
1da177e4
LT
1152 Format: [spp|ps2|epp|ecp|ecpepp]
1153
a9913044
RD
1154 pas2= [HW,OSS] Format:
1155 <io>,<irq>,<dma>,<dma16>,<sb_io>,<sb_irq>,<sb_dma>,<sb_dma16>
1156
1da177e4
LT
1157 pas16= [HW,SCSI]
1158 See header of drivers/scsi/pas16.c.
1159
dd287796
AM
1160 pause_on_oops=
1161 Halt all CPUs after the first oops has been printed for
1162 the specified number of seconds. This is to be used if
1163 your oopses keep scrolling off the screen.
1164
1da177e4
LT
1165 pcbit= [HW,ISDN]
1166
1167 pcd. [PARIDE]
1168 See header of drivers/block/paride/pcd.c.
1169 See also Documentation/paride.txt.
1170
a9913044
RD
1171 pci=option[,option...] [PCI] various PCI subsystem options:
1172 off [IA-32] don't probe for the PCI bus
1173 bios [IA-32] force use of PCI BIOS, don't access
1174 the hardware directly. Use this if your machine
1175 has a non-standard PCI host bridge.
1176 nobios [IA-32] disallow use of PCI BIOS, only direct
1177 hardware access methods are allowed. Use this
1178 if you experience crashes upon bootup and you
1179 suspect they are caused by the BIOS.
1180 conf1 [IA-32] Force use of PCI Configuration
1181 Mechanism 1.
1182 conf2 [IA-32] Force use of PCI Configuration
1183 Mechanism 2.
61be6d66
BH
1184 nommconf [IA-32,X86_64] Disable use of MMCONFIG for PCI
1185 Configuration
40dd2d20
AK
1186 mmconf [IA-32,X86_64] Force MMCONFIG. This is useful
1187 to override the builtin blacklist.
309e57df
MW
1188 nomsi [MSI] If the PCI_MSI kernel config parameter is
1189 enabled, this kernel boot option can be used to
1190 disable the use of MSI interrupts system-wide.
a9913044
RD
1191 nosort [IA-32] Don't sort PCI devices according to
1192 order given by the PCI BIOS. This sorting is
1193 done to get a device order compatible with
1194 older kernels.
1195 biosirq [IA-32] Use PCI BIOS calls to get the interrupt
1196 routing table. These calls are known to be buggy
1197 on several machines and they hang the machine
1198 when used, but on other computers it's the only
1199 way to get the interrupt routing table. Try
1200 this option if the kernel is unable to allocate
1201 IRQs or discover secondary PCI buses on your
1202 motherboard.
1203 rom [IA-32] Assign address space to expansion ROMs.
1204 Use with caution as certain devices share
1205 address decoders between ROMs and other
1206 resources.
1207 irqmask=0xMMMM [IA-32] Set a bit mask of IRQs allowed to be
1208 assigned automatically to PCI devices. You can
1209 make the kernel exclude IRQs of your ISA cards
1210 this way.
120bb424 1211 pirqaddr=0xAAAAA [IA-32] Specify the physical address
a9913044
RD
1212 of the PIRQ table (normally generated
1213 by the BIOS) if it is outside the
1214 F0000h-100000h range.
1215 lastbus=N [IA-32] Scan all buses thru bus #N. Can be
1216 useful if the kernel is unable to find your
1217 secondary buses and you want to tell it
1218 explicitly which ones they are.
1219 assign-busses [IA-32] Always assign all PCI bus
1220 numbers ourselves, overriding
1221 whatever the firmware may have done.
1222 usepirqmask [IA-32] Honor the possible IRQ mask stored
1223 in the BIOS $PIR table. This is needed on
1224 some systems with broken BIOSes, notably
1225 some HP Pavilion N5400 and Omnibook XE3
1226 notebooks. This will have no effect if ACPI
1227 IRQ routing is enabled.
1228 noacpi [IA-32] Do not use ACPI for IRQ routing
1229 or for PCI scanning.
1230 routeirq Do IRQ routing for all PCI devices.
1231 This is normally done in pci_enable_device(),
1232 so this option is a temporary workaround
1233 for broken drivers that don't call it.
1234 firmware [ARM] Do not re-enumerate the bus but instead
1235 just use the configuration from the
1236 bootloader. This is currently used on
1237 IXP2000 systems where the bus has to be
1238 configured a certain way for adjunct CPUs.
1da177e4
LT
1239
1240 pcmv= [HW,PCMCIA] BadgePAD 4
1241
1242 pd. [PARIDE]
1243 See Documentation/paride.txt.
1244
1245 pdcchassis= [PARISC,HW] Disable/Enable PDC Chassis Status codes at
1246 boot time.
1247 Format: { 0 | 1 }
1248 See arch/parisc/kernel/pdc_chassis.c
1249
1250 pf. [PARIDE]
1251 See Documentation/paride.txt.
1252
1253 pg. [PARIDE]
1254 See Documentation/paride.txt.
1255
1256 pirq= [SMP,APIC] Manual mp-table setup
1257 See Documentation/i386/IO-APIC.txt.
1258
1259 plip= [PPT,NET] Parallel port network link
1260 Format: { parport<nr> | timid | 0 }
1261 See also Documentation/parport.txt.
1262
1263 pnpacpi= [ACPI]
1264 { off }
1265
1266 pnpbios= [ISAPNP]
1267 { on | off | curr | res | no-curr | no-res }
1268
1269 pnp_reserve_irq=
1270 [ISAPNP] Exclude IRQs for the autoconfiguration
1271
1272 pnp_reserve_dma=
1273 [ISAPNP] Exclude DMAs for the autoconfiguration
1274
1275 pnp_reserve_io= [ISAPNP] Exclude I/O ports for the autoconfiguration
a9913044 1276 Ranges are in pairs (I/O port base and size).
1da177e4
LT
1277
1278 pnp_reserve_mem=
a9913044
RD
1279 [ISAPNP] Exclude memory regions for the
1280 autoconfiguration.
1da177e4
LT
1281 Ranges are in pairs (memory base and size).
1282
1283 profile= [KNL] Enable kernel profiling via /proc/profile
a9913044
RD
1284 Format: [schedule,]<number>
1285 Param: "schedule" - profile schedule points.
1286 Param: <number> - step/bucket size as a power of 2 for
1287 statistical time based profiling.
1da177e4 1288
a9913044 1289 processor.max_cstate= [HW,ACPI]
1da177e4
LT
1290 Limit processor to maximum C-state
1291 max_cstate=9 overrides any DMI blacklist limit.
1292
41c0d868
LB
1293 processor.nocst [HW,ACPI]
1294 Ignore the _CST method to determine C-states,
1295 instead using the legacy FADT method
1296
1da177e4
LT
1297 prompt_ramdisk= [RAM] List of RAM disks to prompt for floppy disk
1298 before loading.
1299 See Documentation/ramdisk.txt.
1300
a9913044
RD
1301 psmouse.proto= [HW,MOUSE] Highest PS2 mouse protocol extension to
1302 probe for; one of (bare|imps|exps|lifebook|any).
1da177e4
LT
1303 psmouse.rate= [HW,MOUSE] Set desired mouse report rate, in reports
1304 per second.
a9913044
RD
1305 psmouse.resetafter= [HW,MOUSE]
1306 Try to reset the device after so many bad packets
1da177e4
LT
1307 (0 = never).
1308 psmouse.resolution=
1309 [HW,MOUSE] Set desired mouse resolution, in dpi.
1310 psmouse.smartscroll=
a9913044 1311 [HW,MOUSE] Controls Logitech smartscroll autorepeat.
1da177e4
LT
1312 0 = disabled, 1 = enabled (default).
1313
1314 pss= [HW,OSS] Personal Sound System (ECHO ESC614)
a9913044
RD
1315 Format:
1316 <io>,<mss_io>,<mss_irq>,<mss_dma>,<mpu_io>,<mpu_irq>
1da177e4
LT
1317
1318 pt. [PARIDE]
1319 See Documentation/paride.txt.
1320
1321 quiet= [KNL] Disable log messages
a9913044 1322
1da177e4
LT
1323 r128= [HW,DRM]
1324
1325 raid= [HW,RAID]
1326 See Documentation/md.txt.
1327
1328 ramdisk= [RAM] Sizes of RAM disks in kilobytes [deprecated]
1329 See Documentation/ramdisk.txt.
1330
a9913044 1331 ramdisk_blocksize= [RAM]
1da177e4 1332 See Documentation/ramdisk.txt.
a9913044 1333
1da177e4
LT
1334 ramdisk_size= [RAM] Sizes of RAM disks in kilobytes
1335 New name for the ramdisk parameter.
1336 See Documentation/ramdisk.txt.
1337
21a1ea9e
DS
1338 rcu.blimit= [KNL,BOOT] Set maximum number of finished
1339 RCU callbacks to process in one batch.
1340
1341 rcu.qhimark= [KNL,BOOT] Set threshold of queued
1342 RCU callbacks over which batch limiting is disabled.
1343
1344 rcu.qlowmark= [KNL,BOOT] Set threshold of queued
1345 RCU callbacks below which batch limiting is re-enabled.
1346
1347 rcu.rsinterval= [KNL,BOOT,SMP] Set the number of additional
1348 RCU callbacks to queued before forcing reschedule
1349 on all cpus.
1350
ffdfc409
OJ
1351 rdinit= [KNL]
1352 Format: <full_path>
1353 Run specified binary instead of /init from the ramdisk,
1354 used for early userspace startup. See initrd.
1355
1da177e4
LT
1356 reboot= [BUGS=IA-32,BUGS=ARM,BUGS=IA-64] Rebooting mode
1357 Format: <reboot_mode>[,<reboot_mode2>[,...]]
1358 See arch/*/kernel/reboot.c.
1359
1360 reserve= [KNL,BUGS] Force the kernel to ignore some iomem area
1361
a9913044
RD
1362 resume= [SWSUSP]
1363 Specify the partition device for software suspend
1da177e4
LT
1364
1365 rhash_entries= [KNL,NET]
1366 Set number of hash buckets for route cache
1367
1368 riscom8= [HW,SERIAL]
1369 Format: <io_board1>[,<io_board2>[,...<io_boardN>]]
1370
1371 ro [KNL] Mount root device read-only on boot
1372
1373 root= [KNL] Root filesystem
1374
1375 rootdelay= [KNL] Delay (in seconds) to pause before attempting to
1376 mount the root filesystem
1377
1378 rootflags= [KNL] Set root filesystem mount option string
1379
1380 rootfstype= [KNL] Set root filesystem type
1381
1382 rw [KNL] Mount root device read-write on boot
1383
1384 S [KNL] Run init in single mode
1385
1386 sa1100ir [NET]
1387 See drivers/net/irda/sa1100_ir.c.
1388
1389 sb= [HW,OSS]
1390 Format: <io>,<irq>,<dma>,<dma2>
1391
1392 sbni= [NET] Granch SBNI12 leased line adapter
a9913044 1393
1da177e4
LT
1394 sbpcd= [HW,CD] Soundblaster CD adapter
1395 Format: <io>,<type>
1396 See a comment before function sbpcd_setup() in
1397 drivers/cdrom/sbpcd.c.
1398
1399 sc1200wdt= [HW,WDT] SC1200 WDT (watchdog) driver
1400 Format: <io>[,<timeout>[,<isapnp>]]
1401
1402 scsi_debug_*= [SCSI]
1403 See drivers/scsi/scsi_debug.c.
1404
1405 scsi_default_dev_flags=
1406 [SCSI] SCSI default device flags
1407 Format: <integer>
1408
1409 scsi_dev_flags= [SCSI] Black/white list entry for vendor and model
1410 Format: <vendor>:<model>:<flags>
1411 (flags are integer value)
1412
1413 scsi_logging= [SCSI]
1414
1415 selinux [SELINUX] Disable or enable SELinux at boot time.
1416 Format: { "0" | "1" }
1417 See security/selinux/Kconfig help text.
1418 0 -- disable.
1419 1 -- enable.
1420 Default value is set via kernel config option.
1421 If enabled at boot time, /selinux/disable can be used
1422 later to disable prior to initial policy load.
1423
4e5ab4cb
JM
1424 selinux_compat_net =
1425 [SELINUX] Set initial selinux_compat_net flag value.
1426 Format: { "0" | "1" }
1427 0 -- use new secmark-based packet controls
1428 1 -- use legacy packet controls
1429 Default value is 0 (preferred).
1430 Value can be changed at runtime via
1431 /selinux/compat_net.
1432
1da177e4
LT
1433 serialnumber [BUGS=IA-32]
1434
a9913044
RD
1435 sg_def_reserved_size= [SCSI]
1436
1da177e4
LT
1437 sgalaxy= [HW,OSS]
1438 Format: <io>,<irq>,<dma>,<dma2>,<sgbase>
1439
1440 shapers= [NET]
1441 Maximal number of shapers.
a9913044 1442
1da177e4
LT
1443 sim710= [SCSI,HW]
1444 See header of drivers/scsi/sim710.c.
1445
1446 simeth= [IA-64]
1447 simscsi=
a9913044 1448
1da177e4
LT
1449 sjcd= [HW,CD]
1450 Format: <io>,<irq>,<dma>
1451 See header of drivers/cdrom/sjcd.c.
1452
1453 slram= [HW,MTD]
1454
1455 smart2= [HW]
1456 Format: <io1>[,<io2>[,...,<io8>]]
1457
1458 snd-ad1816a= [HW,ALSA]
1459
1460 snd-ad1848= [HW,ALSA]
1461
1462 snd-ali5451= [HW,ALSA]
1463
1464 snd-als100= [HW,ALSA]
1465
1466 snd-als4000= [HW,ALSA]
1467
1468 snd-azt2320= [HW,ALSA]
1469
1470 snd-cmi8330= [HW,ALSA]
1471
1472 snd-cmipci= [HW,ALSA]
1473
1474 snd-cs4231= [HW,ALSA]
1475
1476 snd-cs4232= [HW,ALSA]
1477
1478 snd-cs4236= [HW,ALSA]
1479
1480 snd-cs4281= [HW,ALSA]
1481
1482 snd-cs46xx= [HW,ALSA]
1483
1484 snd-dt019x= [HW,ALSA]
1485
1486 snd-dummy= [HW,ALSA]
1487
1488 snd-emu10k1= [HW,ALSA]
1489
1490 snd-ens1370= [HW,ALSA]
1491
1492 snd-ens1371= [HW,ALSA]
1493
1494 snd-es968= [HW,ALSA]
1495
1496 snd-es1688= [HW,ALSA]
1497
1498 snd-es18xx= [HW,ALSA]
1499
1500 snd-es1938= [HW,ALSA]
1501
1502 snd-es1968= [HW,ALSA]
1503
1504 snd-fm801= [HW,ALSA]
1505
1506 snd-gusclassic= [HW,ALSA]
1507
1508 snd-gusextreme= [HW,ALSA]
1509
1510 snd-gusmax= [HW,ALSA]
1511
1512 snd-hdsp= [HW,ALSA]
1513
1514 snd-ice1712= [HW,ALSA]
1515
1516 snd-intel8x0= [HW,ALSA]
1517
1518 snd-interwave= [HW,ALSA]
1519
1520 snd-interwave-stb=
1521 [HW,ALSA]
1522
1523 snd-korg1212= [HW,ALSA]
1524
1525 snd-maestro3= [HW,ALSA]
1526
1527 snd-mpu401= [HW,ALSA]
1528
1529 snd-mtpav= [HW,ALSA]
1530
1531 snd-nm256= [HW,ALSA]
1532
1533 snd-opl3sa2= [HW,ALSA]
1534
1535 snd-opti92x-ad1848=
1536 [HW,ALSA]
1537
1538 snd-opti92x-cs4231=
1539 [HW,ALSA]
1540
1541 snd-opti93x= [HW,ALSA]
1542
1543 snd-pmac= [HW,ALSA]
1544
1545 snd-rme32= [HW,ALSA]
1546
1547 snd-rme96= [HW,ALSA]
1548
1549 snd-rme9652= [HW,ALSA]
1550
1551 snd-sb8= [HW,ALSA]
1552
1553 snd-sb16= [HW,ALSA]
1554
1555 snd-sbawe= [HW,ALSA]
1556
1557 snd-serial= [HW,ALSA]
1558
1559 snd-sgalaxy= [HW,ALSA]
1560
1561 snd-sonicvibes= [HW,ALSA]
1562
1563 snd-sun-amd7930=
1564 [HW,ALSA]
1565
1566 snd-sun-cs4231= [HW,ALSA]
1567
1568 snd-trident= [HW,ALSA]
1569
1570 snd-usb-audio= [HW,ALSA,USB]
1571
1572 snd-via82xx= [HW,ALSA]
1573
1574 snd-virmidi= [HW,ALSA]
1575
1576 snd-wavefront= [HW,ALSA]
1577
1578 snd-ymfpci= [HW,ALSA]
a9913044 1579
1da177e4
LT
1580 sonicvibes= [HW,OSS]
1581 Format: <reverb>
a9913044 1582
1da177e4
LT
1583 sonycd535= [HW,CD]
1584 Format: <io>[,<irq>]
1585
1586 sonypi.*= [HW] Sony Programmable I/O Control Device driver
1587 See Documentation/sonypi.txt
1588
1589 specialix= [HW,SERIAL] Specialix multi-serial port adapter
1590 See Documentation/specialix.txt.
1591
1592 spia_io_base= [HW,MTD]
1593 spia_fio_base=
1594 spia_pedr=
1595 spia_peddr=
1596
1597 sscape= [HW,OSS]
1598 Format: <io>,<irq>,<dma>,<mpu_io>,<mpu_irq>
a9913044 1599
1da177e4
LT
1600 st= [HW,SCSI] SCSI tape parameters (buffers, etc.)
1601 See Documentation/scsi/st.txt.
1602
1603 st0x= [HW,SCSI]
1604 See header of drivers/scsi/seagate.c.
1605
1606 sti= [PARISC,HW]
1607 Format: <num>
1608 Set the STI (builtin display/keyboard on the HP-PARISC
1609 machines) console (graphic card) which should be used
1610 as the initial boot-console.
1611 See also comment in drivers/video/console/sticore.c.
1612
1613 sti_font= [HW]
1614 See comment in drivers/video/console/sticore.c.
1615
1616 stifb= [HW]
1617 Format: bpp:<bpp1>[:<bpp2>[:<bpp3>...]]
1618
1da177e4 1619 swiotlb= [IA-64] Number of I/O TLB slabs
a9913044 1620
1da177e4
LT
1621 switches= [HW,M68k]
1622
1623 sym53c416= [HW,SCSI]
1624 See header of drivers/scsi/sym53c416.c.
1625
1626 t128= [HW,SCSI]
1627 See header of drivers/scsi/t128.c.
1628
1629 tdfx= [HW,DRM]
1630
1631 thash_entries= [KNL,NET]
1632 Set number of hash buckets for TCP connection
1633
1634 time Show timing data prefixed to each printk message line
1635
734efb46 1636 clocksource= [GENERIC_TIME] Override the default clocksource
1637 Override the default clocksource and use the clocksource
1638 with the name specified.
1639
1da177e4
LT
1640 tipar.timeout= [HW,PPT]
1641 Set communications timeout in tenths of a second
1642 (default 15).
1643
1644 tipar.delay= [HW,PPT]
1645 Set inter-bit delay in microseconds (default 10).
1646
1647 tmc8xx= [HW,SCSI]
1648 See header of drivers/scsi/seagate.c.
1649
1650 tmscsim= [HW,SCSI]
1651 See comment before function dc390_setup() in
1652 drivers/scsi/tmscsim.c.
1653
1654 tp720= [HW,PS2]
1655
1656 trix= [HW,OSS] MediaTrix AudioTrix Pro
a9913044
RD
1657 Format:
1658 <io>,<irq>,<dma>,<dma2>,<sb_io>,<sb_irq>,<sb_dma>,<mpu_io>,<mpu_irq>
1659
1da177e4
LT
1660 tsdev.xres= [TS] Horizontal screen resolution.
1661 tsdev.yres= [TS] Vertical screen resolution.
1662
a9913044
RD
1663 turbografx.map[2|3]= [HW,JOY]
1664 TurboGraFX parallel port interface
1665 Format:
1666 <port#>,<js1>,<js2>,<js3>,<js4>,<js5>,<js6>,<js7>
1da177e4
LT
1667 See also Documentation/input/joystick-parport.txt
1668
1669 u14-34f= [HW,SCSI] UltraStor 14F/34F SCSI host adapter
1670 See header of drivers/scsi/u14-34f.c.
1671
1672 uart401= [HW,OSS]
1673 Format: <io>,<irq>
1674
1675 uart6850= [HW,OSS]
1676 Format: <io>,<irq>
1677
1da177e4
LT
1678 usbhid.mousepoll=
1679 [USBHID] The interval which mice are to be polled at.
a9913044 1680
e6e5494c
IM
1681 vdso= [IA-32]
1682 vdso=1: enable VDSO (default)
1683 vdso=0: disable VDSO mapping
1684
1da177e4
LT
1685 video= [FB] Frame buffer configuration
1686 See Documentation/fb/modedb.txt.
1687
1688 vga= [BOOT,IA-32] Select a particular video mode
a9913044
RD
1689 See Documentation/i386/boot.txt and
1690 Documentation/svga.txt.
1da177e4
LT
1691 Use vga=ask for menu.
1692 This is actually a boot loader parameter; the value is
1693 passed to the kernel using a special protocol.
1694
a9913044 1695 vmalloc=nn[KMG] [KNL,BOOT] Forces the vmalloc area to have an exact
1da177e4
LT
1696 size of <nn>. This can be used to increase the
1697 minimum size (128MB on x86). It can also be used to
1698 decrease the size and leave more room for directly
1699 mapped kernel RAM.
1700
585c3047
PO
1701 vmhalt= [KNL,S390] Perform z/VM CP command after system halt.
1702 Format: <command>
1da177e4 1703
585c3047
PO
1704 vmpanic= [KNL,S390] Perform z/VM CP command after kernel panic.
1705 Format: <command>
1706
1707 vmpoff= [KNL,S390] Perform z/VM CP command after power off.
1708 Format: <command>
a9913044 1709
1da177e4
LT
1710 waveartist= [HW,OSS]
1711 Format: <io>,<irq>,<dma>,<dma2>
a9913044 1712
1da177e4
LT
1713 wd33c93= [HW,SCSI]
1714 See header of drivers/scsi/wd33c93.c.
1715
1716 wd7000= [HW,SCSI]
1717 See header of drivers/scsi/wd7000.c.
1718
1719 wdt= [WDT] Watchdog
1720 See Documentation/watchdog/watchdog.txt.
1721
1722 xd= [HW,XT] Original XT pre-IDE (RLL encoded) disks.
1723 xd_geo= See header of drivers/block/xd.c.
1724
1725 xirc2ps_cs= [NET,PCMCIA]
a9913044
RD
1726 Format:
1727 <irq>,<irq_mask>,<io>,<full_duplex>,<do_sound>,<lockup_hack>[,<irq2>[,<irq3>[,<irq4>]]]
1da177e4 1728
a62eaf15
AK
1729 norandmaps Don't use address space randomization
1730 Equivalent to echo 0 > /proc/sys/kernel/randomize_va_space
1731
1da177e4 1732
a9913044 1733______________________________________________________________________
1da177e4
LT
1734
1735TODO:
1736
1737 Add documentation for ALSA options.
1738 Add more DRM drivers.
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