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1 Kernel Parameters
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
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
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:
31
32 ACPI ACPI support is enabled.
33 AGP AGP (Accelerated Graphics Port) is enabled.
34 ALSA ALSA sound support is enabled.
35 APIC APIC support is enabled.
36 APM Advanced Power Management support is enabled.
37 AX25 Appropriate AX.25 support is enabled.
38 BLACKFIN Blackfin architecture is enabled.
39 DRM Direct Rendering Management support is enabled.
40 EDD BIOS Enhanced Disk Drive Services (EDD) is enabled
41 EFI EFI Partitioning (GPT) is enabled
42 EIDE EIDE/ATAPI support is enabled.
43 FB The frame buffer device is enabled.
44 HW Appropriate hardware is enabled.
45 IA-64 IA-64 architecture is enabled.
46 IOSCHED More than one I/O scheduler is enabled.
47 IP_PNP IP DHCP, BOOTP, or RARP is enabled.
48 ISAPNP ISA PnP code is enabled.
49 ISDN Appropriate ISDN support is enabled.
50 JOY Appropriate joystick support is enabled.
51 LIBATA Libata driver is enabled
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.
60 MSI Message Signaled Interrupts (PCI).
61 MTD MTD (Memory Technology Device) support is enabled.
62 NET Appropriate network support is enabled.
63 NUMA NUMA support is enabled.
64 GENERIC_TIME The generic timeofday code is enabled.
65 NFS Appropriate NFS support is enabled.
66 OSS OSS sound support is enabled.
67 PV_OPS A paravirtualized kernel is enabled.
68 PARIDE The ParIDE (parallel port IDE) subsystem is enabled.
69 PARISC The PA-RISC architecture is enabled.
70 PCI PCI bus support is enabled.
71 PCIE PCI Express support is enabled.
72 PCMCIA The PCMCIA subsystem is enabled.
73 PNP Plug & Play support is enabled.
74 PPC PowerPC architecture is enabled.
75 PPT Parallel port support is enabled.
76 PS2 Appropriate PS/2 support is enabled.
77 RAM RAM disk support is enabled.
78 S390 S390 architecture is enabled.
79 SCSI Appropriate SCSI support is enabled.
80 A lot of drivers has their options described inside of
81 Documentation/scsi/.
82 SELINUX SELinux support is enabled.
83 SERIAL Serial support is enabled.
84 SH SuperH architecture is enabled.
85 SMP The kernel is an SMP kernel.
86 SPARC Sparc architecture is enabled.
87 SWSUSP Software suspend is enabled.
88 TS Appropriate touchscreen support is enabled.
89 USB USB support is enabled.
90 USBHID USB Human Interface Device support is enabled.
91 V4L Video For Linux support is enabled.
92 VGA The VGA console has been enabled.
93 VT Virtual terminal support is enabled.
94 WDT Watchdog support is enabled.
95 XT IBM PC/XT MFM hard disk support is enabled.
96 X86-32 X86-32, aka i386 architecture is enabled.
97 X86-64 X86-64 architecture is enabled.
98 More X86-64 boot options can be found in
99 Documentation/x86_64/boot-options.txt .
100
101 In addition, the following text indicates that the option:
102
103 BUGS= Relates to possible processor bugs on the said processor.
104 KNL Is a kernel start-up parameter.
105 BOOT Is a boot loader parameter.
106
107 Parameters denoted with BOOT are actually interpreted by the boot
108 loader, and have no meaning to the kernel directly.
109 Do not modify the syntax of boot loader parameters without extreme
110 need or coordination with <Documentation/i386/boot.txt>.
111
112 There are also arch-specific kernel-parameters not documented here.
113 See for example <Documentation/x86_64/boot-options.txt>.
114
115 Note that ALL kernel parameters listed below are CASE SENSITIVE, and that
116 a trailing = on the name of any parameter states that that parameter will
117 be entered as an environment variable, whereas its absence indicates that
118 it will appear as a kernel argument readable via /proc/cmdline by programs
119 running once the system is up.
120
121 The number of kernel parameters is not limited, but the length of the
122 complete command line (parameters including spaces etc.) is limited to
123 a fixed number of characters. This limit depends on the architecture
124 and is between 256 and 4096 characters. It is defined in the file
125 ./include/asm/setup.h as COMMAND_LINE_SIZE.
126
127
128 acpi= [HW,ACPI,X86-64,i386]
129 Advanced Configuration and Power Interface
130 Format: { force | off | ht | strict | noirq }
131 force -- enable ACPI if default was off
132 off -- disable ACPI if default was on
133 noirq -- do not use ACPI for IRQ routing
134 ht -- run only enough ACPI to enable Hyper Threading
135 strict -- Be less tolerant of platforms that are not
136 strictly ACPI specification compliant.
137
138 See also Documentation/pm.txt, pci=noacpi
139
140 acpi_apic_instance= [ACPI, IOAPIC]
141 Format: <int>
142 2: use 2nd APIC table, if available
143 1,0: use 1st APIC table
144 default: 0
145
146 acpi_sleep= [HW,ACPI] Sleep options
147 Format: { s3_bios, s3_mode }
148 See Documentation/power/video.txt
149
150 acpi_sci= [HW,ACPI] ACPI System Control Interrupt trigger mode
151 Format: { level | edge | high | low }
152
153 acpi_irq_balance [HW,ACPI]
154 ACPI will balance active IRQs
155 default in APIC mode
156
157 acpi_irq_nobalance [HW,ACPI]
158 ACPI will not move active IRQs (default)
159 default in PIC mode
160
161 acpi_irq_pci= [HW,ACPI] If irq_balance, clear listed IRQs for
162 use by PCI
163 Format: <irq>,<irq>...
164
165 acpi_irq_isa= [HW,ACPI] If irq_balance, mark listed IRQs used by ISA
166 Format: <irq>,<irq>...
167
168 acpi_no_auto_ssdt [HW,ACPI] Disable automatic loading of SSDT
169
170 acpi_os_name= [HW,ACPI] Tell ACPI BIOS the name of the OS
171 Format: To spoof as Windows 98: ="Microsoft Windows"
172
173 acpi_osi= [HW,ACPI] Modify list of supported OS interface strings
174 acpi_osi="string1" # add string1 -- only one string
175 acpi_osi="!string2" # remove built-in string2
176 acpi_osi= # disable all strings
177
178 acpi_serialize [HW,ACPI] force serialization of AML methods
179
180 acpi_skip_timer_override [HW,ACPI]
181 Recognize and ignore IRQ0/pin2 Interrupt Override.
182 For broken nForce2 BIOS resulting in XT-PIC timer.
183 acpi_use_timer_override [HW,ACPI}
184 Use timer override. For some broken Nvidia NF5 boards
185 that require a timer override, but don't have
186 HPET
187
188 acpi.debug_layer= [HW,ACPI]
189 Format: <int>
190 Each bit of the <int> indicates an ACPI debug layer,
191 1: enable, 0: disable. It is useful for boot time
192 debugging. After system has booted up, it can be set
193 via /sys/module/acpi/parameters/debug_layer.
194 CONFIG_ACPI_DEBUG must be enabled for this to produce any output.
195 Available bits (add the numbers together) to enable debug output
196 for specific parts of the ACPI subsystem:
197 0x01 utilities 0x02 hardware 0x04 events 0x08 tables
198 0x10 namespace 0x20 parser 0x40 dispatcher
199 0x80 executer 0x100 resources 0x200 acpica debugger
200 0x400 os services 0x800 acpica disassembler.
201 The number can be in decimal or prefixed with 0x in hex.
202 Warning: Many of these options can produce a lot of
203 output and make your system unusable. Be very careful.
204
205 acpi.debug_level= [HW,ACPI]
206 Format: <int>
207 Each bit of the <int> indicates an ACPI debug level,
208 1: enable, 0: disable. It is useful for boot time
209 debugging. After system has booted up, it can be set
210 via /sys/module/acpi/parameters/debug_level.
211 CONFIG_ACPI_DEBUG must be enabled for this to produce any output.
212 Available bits (add the numbers together) to enable different
213 debug output levels of the ACPI subsystem:
214 0x01 error 0x02 warn 0x04 init 0x08 debug object
215 0x10 info 0x20 init names 0x40 parse 0x80 load
216 0x100 dispatch 0x200 execute 0x400 names 0x800 operation region
217 0x1000 bfield 0x2000 tables 0x4000 values 0x8000 objects
218 0x10000 resources 0x20000 user requests 0x40000 package.
219 The number can be in decimal or prefixed with 0x in hex.
220 Warning: Many of these options can produce a lot of
221 output and make your system unusable. Be very careful.
222
223
224 acpi_fake_ecdt [HW,ACPI] Workaround failure due to BIOS lacking ECDT
225
226 acpi_pm_good [X86-32,X86-64]
227 Override the pmtimer bug detection: force the kernel
228 to assume that this machine's pmtimer latches its value
229 and always returns good values.
230
231 agp= [AGP]
232 { off | try_unsupported }
233 off: disable AGP support
234 try_unsupported: try to drive unsupported chipsets
235 (may crash computer or cause data corruption)
236
237 enable_timer_pin_1 [i386,x86-64]
238 Enable PIN 1 of APIC timer
239 Can be useful to work around chipset bugs
240 (in particular on some ATI chipsets).
241 The kernel tries to set a reasonable default.
242
243 disable_timer_pin_1 [i386,x86-64]
244 Disable PIN 1 of APIC timer
245 Can be useful to work around chipset bugs.
246
247 ad1848= [HW,OSS]
248 Format: <io>,<irq>,<dma>,<dma2>,<type>
249
250 advansys= [HW,SCSI]
251 See header of drivers/scsi/advansys.c.
252
253 advwdt= [HW,WDT] Advantech WDT
254 Format: <iostart>,<iostop>
255
256 aedsp16= [HW,OSS] Audio Excel DSP 16
257 Format: <io>,<irq>,<dma>,<mss_io>,<mpu_io>,<mpu_irq>
258 See also header of sound/oss/aedsp16.c.
259
260 aha152x= [HW,SCSI]
261 See Documentation/scsi/aha152x.txt.
262
263 aha1542= [HW,SCSI]
264 Format: <portbase>[,<buson>,<busoff>[,<dmaspeed>]]
265
266 aic7xxx= [HW,SCSI]
267 See Documentation/scsi/aic7xxx.txt.
268
269 aic79xx= [HW,SCSI]
270 See Documentation/scsi/aic79xx.txt.
271
272 amijoy.map= [HW,JOY] Amiga joystick support
273 Map of devices attached to JOY0DAT and JOY1DAT
274 Format: <a>,<b>
275 See also Documentation/kernel/input/joystick.txt
276
277 analog.map= [HW,JOY] Analog joystick and gamepad support
278 Specifies type or capabilities of an analog joystick
279 connected to one of 16 gameports
280 Format: <type1>,<type2>,..<type16>
281
282 apc= [HW,SPARC]
283 Power management functions (SPARCstation-4/5 + deriv.)
284 Format: noidle
285 Disable APC CPU standby support. SPARCstation-Fox does
286 not play well with APC CPU idle - disable it if you have
287 APC and your system crashes randomly.
288
289 apic= [APIC,i386] Advanced Programmable Interrupt Controller
290 Change the output verbosity whilst booting
291 Format: { quiet (default) | verbose | debug }
292 Change the amount of debugging information output
293 when initialising the APIC and IO-APIC components.
294
295 apm= [APM] Advanced Power Management
296 See header of arch/i386/kernel/apm.c.
297
298 applicom= [HW]
299 Format: <mem>,<irq>
300
301 arcrimi= [HW,NET] ARCnet - "RIM I" (entirely mem-mapped) cards
302 Format: <io>,<irq>,<nodeID>
303
304 ataflop= [HW,M68k]
305
306 atarimouse= [HW,MOUSE] Atari Mouse
307
308 atascsi= [HW,SCSI] Atari SCSI
309
310 atkbd.extra= [HW] Enable extra LEDs and keys on IBM RapidAccess,
311 EzKey and similar keyboards
312
313 atkbd.reset= [HW] Reset keyboard during initialization
314
315 atkbd.set= [HW] Select keyboard code set
316 Format: <int> (2 = AT (default), 3 = PS/2)
317
318 atkbd.scroll= [HW] Enable scroll wheel on MS Office and similar
319 keyboards
320
321 atkbd.softraw= [HW] Choose between synthetic and real raw mode
322 Format: <bool> (0 = real, 1 = synthetic (default))
323
324 atkbd.softrepeat= [HW]
325 Use software keyboard repeat
326
327 autotest [IA64]
328
329 baycom_epp= [HW,AX25]
330 Format: <io>,<mode>
331
332 baycom_par= [HW,AX25] BayCom Parallel Port AX.25 Modem
333 Format: <io>,<mode>
334 See header of drivers/net/hamradio/baycom_par.c.
335
336 baycom_ser_fdx= [HW,AX25]
337 BayCom Serial Port AX.25 Modem (Full Duplex Mode)
338 Format: <io>,<irq>,<mode>[,<baud>]
339 See header of drivers/net/hamradio/baycom_ser_fdx.c.
340
341 baycom_ser_hdx= [HW,AX25]
342 BayCom Serial Port AX.25 Modem (Half Duplex Mode)
343 Format: <io>,<irq>,<mode>
344 See header of drivers/net/hamradio/baycom_ser_hdx.c.
345
346 blkmtd_device= [HW,MTD]
347 blkmtd_erasesz=
348 blkmtd_ro=
349 blkmtd_bs=
350 blkmtd_count=
351
352 bttv.card= [HW,V4L] bttv (bt848 + bt878 based grabber cards)
353 bttv.radio= Most important insmod options are available as
354 kernel args too.
355 bttv.pll= See Documentation/video4linux/bttv/Insmod-options
356 bttv.tuner= and Documentation/video4linux/bttv/CARDLIST
357
358 BusLogic= [HW,SCSI]
359 See drivers/scsi/BusLogic.c, comment before function
360 BusLogic_ParseDriverOptions().
361
362 c101= [NET] Moxa C101 synchronous serial card
363
364 cachesize= [BUGS=X86-32] Override level 2 CPU cache size detection.
365 Sometimes CPU hardware bugs make them report the cache
366 size incorrectly. The kernel will attempt work arounds
367 to fix known problems, but for some CPUs it is not
368 possible to determine what the correct size should be.
369 This option provides an override for these situations.
370
371 chandev= [HW,NET] Generic channel device initialisation
372
373 checkreqprot [SELINUX] Set initial checkreqprot flag value.
374 Format: { "0" | "1" }
375 See security/selinux/Kconfig help text.
376 0 -- check protection applied by kernel (includes
377 any implied execute protection).
378 1 -- check protection requested by application.
379 Default value is set via a kernel config option.
380 Value can be changed at runtime via
381 /selinux/checkreqprot.
382
383 clock= [BUGS=X86-32, HW] gettimeofday clocksource override.
384 [Deprecated]
385 Forces specified clocksource (if available) to be used
386 when calculating gettimeofday(). If specified
387 clocksource is not available, it defaults to PIT.
388 Format: { pit | tsc | cyclone | pmtmr }
389
390 clocksource= [GENERIC_TIME] Override the default clocksource
391 Format: <string>
392 Override the default clocksource and use the clocksource
393 with the name specified.
394 Some clocksource names to choose from, depending on
395 the platform:
396 [all] jiffies (this is the base, fallback clocksource)
397 [ACPI] acpi_pm
398 [ARM] imx_timer1,OSTS,netx_timer,mpu_timer2,
399 pxa_timer,timer3,32k_counter,timer0_1
400 [AVR32] avr32
401 [X86-32] pit,hpet,tsc,vmi-timer;
402 scx200_hrt on Geode; cyclone on IBM x440
403 [MIPS] MIPS
404 [PARISC] cr16
405 [S390] tod
406 [SH] SuperH
407 [SPARC64] tick
408 [X86-64] hpet,tsc
409
410 code_bytes [IA32] How many bytes of object code to print in an
411 oops report.
412 Range: 0 - 8192
413 Default: 64
414
415 disable_8254_timer
416 enable_8254_timer
417 [IA32/X86_64] Disable/Enable interrupt 0 timer routing
418 over the 8254 in addition to over the IO-APIC. The
419 kernel tries to set a sensible default.
420
421 hpet= [X86-32,HPET] option to disable HPET and use PIT.
422 Format: disable
423
424 com20020= [HW,NET] ARCnet - COM20020 chipset
425 Format:
426 <io>[,<irq>[,<nodeID>[,<backplane>[,<ckp>[,<timeout>]]]]]
427
428 com90io= [HW,NET] ARCnet - COM90xx chipset (IO-mapped buffers)
429 Format: <io>[,<irq>]
430
431 com90xx= [HW,NET]
432 ARCnet - COM90xx chipset (memory-mapped buffers)
433 Format: <io>[,<irq>[,<memstart>]]
434
435 condev= [HW,S390] console device
436 conmode=
437
438 console= [KNL] Output console device and options.
439
440 tty<n> Use the virtual console device <n>.
441
442 ttyS<n>[,options]
443 ttyUSB0[,options]
444 Use the specified serial port. The options are of
445 the form "bbbbpnf", where "bbbb" is the baud rate,
446 "p" is parity ("n", "o", or "e"), "n" is number of
447 bits, and "f" is flow control ("r" for RTS or
448 omit it). Default is "9600n8".
449
450 See Documentation/serial-console.txt for more
451 information. See
452 Documentation/networking/netconsole.txt for an
453 alternative.
454
455 uart[8250],io,<addr>[,options]
456 uart[8250],mmio,<addr>[,options]
457 Start an early, polled-mode console on the 8250/16550
458 UART at the specified I/O port or MMIO address,
459 switching to the matching ttyS device later. The
460 options are the same as for ttyS, above.
461
462 earlycon= [KNL] Output early console device and options.
463 uart[8250],io,<addr>[,options]
464 uart[8250],mmio,<addr>[,options]
465 Start an early, polled-mode console on the 8250/16550
466 UART at the specified I/O port or MMIO address.
467 The options are the same as for ttyS, above.
468
469 cpcihp_generic= [HW,PCI] Generic port I/O CompactPCI driver
470 Format:
471 <first_slot>,<last_slot>,<port>,<enum_bit>[,<debug>]
472
473 crashkernel=nn[KMG]@ss[KMG]
474 [KNL] Reserve a chunk of physical memory to
475 hold a kernel to switch to with kexec on panic.
476
477 cs4232= [HW,OSS]
478 Format: <io>,<irq>,<dma>,<dma2>,<mpuio>,<mpuirq>
479
480 cs89x0_dma= [HW,NET]
481 Format: <dma>
482
483 cs89x0_media= [HW,NET]
484 Format: { rj45 | aui | bnc }
485
486 cyclades= [HW,SERIAL] Cyclades multi-serial port adapter.
487
488 dasd= [HW,NET]
489 See header of drivers/s390/block/dasd_devmap.c.
490
491 db9.dev[2|3]= [HW,JOY] Multisystem joystick support via parallel port
492 (one device per port)
493 Format: <port#>,<type>
494 See also Documentation/input/joystick-parport.txt
495
496 debug [KNL] Enable kernel debugging (events log level).
497
498 debug_locks_verbose=
499 [KNL] verbose self-tests
500 Format=<0|1>
501 Print debugging info while doing the locking API
502 self-tests.
503 We default to 0 (no extra messages), setting it to
504 1 will print _a lot_ more information - normally
505 only useful to kernel developers.
506
507 decnet= [HW,NET]
508 Format: <area>[,<node>]
509 See also Documentation/networking/decnet.txt.
510
511 default_blu= [VT]
512 Format: <blue0>,<blue1>,<blue2>,...,<blue15>
513 Change the default blue palette of the console.
514 This is a 16-member array composed of values
515 ranging from 0-255.
516
517 default_grn= [VT]
518 Format: <green0>,<green1>,<green2>,...,<green15>
519 Change the default green palette of the console.
520 This is a 16-member array composed of values
521 ranging from 0-255.
522
523 default_red= [VT]
524 Format: <red0>,<red1>,<red2>,...,<red15>
525 Change the default red palette of the console.
526 This is a 16-member array composed of values
527 ranging from 0-255.
528
529 default_utf8= [VT]
530 Format=<0|1>
531 Set system-wide default UTF-8 mode for all tty's.
532 Default is 0 and by setting to 1, it enables UTF-8
533 mode for all newly opened or allocated terminals.
534
535 dhash_entries= [KNL]
536 Set number of hash buckets for dentry cache.
537
538 digi= [HW,SERIAL]
539 IO parameters + enable/disable command.
540
541 digiepca= [HW,SERIAL]
542 See drivers/char/README.epca and
543 Documentation/digiepca.txt.
544
545 dmascc= [HW,AX25,SERIAL] AX.25 Z80SCC driver with DMA
546 support available.
547 Format: <io_dev0>[,<io_dev1>[,..<io_dev32>]]
548
549 dmasound= [HW,OSS] Sound subsystem buffers
550
551 dscc4.setup= [NET]
552
553 dtc3181e= [HW,SCSI]
554
555 earlyprintk= [X86-32,X86-64,SH,BLACKFIN]
556 earlyprintk=vga
557 earlyprintk=serial[,ttySn[,baudrate]]
558
559 Append ",keep" to not disable it when the real console
560 takes over.
561
562 Only vga or serial at a time, not both.
563
564 Currently only ttyS0 and ttyS1 are supported.
565
566 Interaction with the standard serial driver is not
567 very good.
568
569 The VGA output is eventually overwritten by the real
570 console.
571
572 eata= [HW,SCSI]
573
574 ec_intr= [HW,ACPI] ACPI Embedded Controller interrupt mode
575 Format: <int>
576 0: polling mode
577 non-0: interrupt mode (default)
578
579 eda= [HW,PS2]
580
581 edb= [HW,PS2]
582
583 edd= [EDD]
584 Format: {"of[f]" | "sk[ipmbr]"}
585 See comment in arch/i386/boot/edd.S
586
587 eicon= [HW,ISDN]
588 Format: <id>,<membase>,<irq>
589
590 eisa_irq_edge= [PARISC,HW]
591 See header of drivers/parisc/eisa.c.
592
593 elanfreq= [X86-32]
594 See comment before function elanfreq_setup() in
595 arch/i386/kernel/cpu/cpufreq/elanfreq.c.
596
597 elevator= [IOSCHED]
598 Format: {"anticipatory" | "cfq" | "deadline" | "noop"}
599 See Documentation/block/as-iosched.txt and
600 Documentation/block/deadline-iosched.txt for details.
601
602 elfcorehdr= [X86-32, X86_64]
603 Specifies physical address of start of kernel core
604 image elf header. Generally kexec loader will
605 pass this option to capture kernel.
606 See Documentation/kdump/kdump.txt for details.
607
608 enforcing [SELINUX] Set initial enforcing status.
609 Format: {"0" | "1"}
610 See security/selinux/Kconfig help text.
611 0 -- permissive (log only, no denials).
612 1 -- enforcing (deny and log).
613 Default value is 0.
614 Value can be changed at runtime via /selinux/enforce.
615
616 es1371= [HW,OSS]
617 Format: <spdif>,[<nomix>,[<amplifier>]]
618 See also header of sound/oss/es1371.c.
619
620 ether= [HW,NET] Ethernet cards parameters
621 This option is obsoleted by the "netdev=" option, which
622 has equivalent usage. See its documentation for details.
623
624 eurwdt= [HW,WDT] Eurotech CPU-1220/1410 onboard watchdog.
625 Format: <io>[,<irq>]
626
627 failslab=
628 fail_page_alloc=
629 fail_make_request=[KNL]
630 General fault injection mechanism.
631 Format: <interval>,<probability>,<space>,<times>
632 See also /Documentation/fault-injection/.
633
634 fd_mcs= [HW,SCSI]
635 See header of drivers/scsi/fd_mcs.c.
636
637 fdomain= [HW,SCSI]
638 See header of drivers/scsi/fdomain.c.
639
640 floppy= [HW]
641 See Documentation/floppy.txt.
642
643 gamecon.map[2|3]=
644 [HW,JOY] Multisystem joystick and NES/SNES/PSX pad
645 support via parallel port (up to 5 devices per port)
646 Format: <port#>,<pad1>,<pad2>,<pad3>,<pad4>,<pad5>
647 See also Documentation/input/joystick-parport.txt
648
649 gamma= [HW,DRM]
650
651 gdth= [HW,SCSI]
652 See header of drivers/scsi/gdth.c.
653
654 gpt [EFI] Forces disk with valid GPT signature but
655 invalid Protective MBR to be treated as GPT.
656
657 gvp11= [HW,SCSI]
658
659 hashdist= [KNL,NUMA] Large hashes allocated during boot
660 are distributed across NUMA nodes. Defaults on
661 for IA-64, off otherwise.
662 Format: 0 | 1 (for off | on)
663
664 hcl= [IA-64] SGI's Hardware Graph compatibility layer
665
666 hd= [EIDE] (E)IDE hard drive subsystem geometry
667 Format: <cyl>,<head>,<sect>
668
669 hd?= [HW] (E)IDE subsystem
670 hd?lun= See Documentation/ide.txt.
671
672 highmem=nn[KMG] [KNL,BOOT] forces the highmem zone to have an exact
673 size of <nn>. This works even on boxes that have no
674 highmem otherwise. This also works to reduce highmem
675 size on bigger boxes.
676
677 highres= [KNL] Enable/disable high resolution timer mode.
678 Valid parameters: "on", "off"
679 Default: "on"
680
681 hisax= [HW,ISDN]
682 See Documentation/isdn/README.HiSax.
683
684 hugepages= [HW,X86-32,IA-64] Maximal number of HugeTLB pages.
685
686 i8042.direct [HW] Put keyboard port into non-translated mode
687 i8042.dumbkbd [HW] Pretend that controller can only read data from
688 keyboard and cannot control its state
689 (Don't attempt to blink the leds)
690 i8042.noaux [HW] Don't check for auxiliary (== mouse) port
691 i8042.nokbd [HW] Don't check/create keyboard port
692 i8042.nomux [HW] Don't check presence of an active multiplexing
693 controller
694 i8042.nopnp [HW] Don't use ACPIPnP / PnPBIOS to discover KBD/AUX
695 controllers
696 i8042.panicblink=
697 [HW] Frequency with which keyboard LEDs should blink
698 when kernel panics (default is 0.5 sec)
699 i8042.reset [HW] Reset the controller during init and cleanup
700 i8042.unlock [HW] Unlock (ignore) the keylock
701
702 i810= [HW,DRM]
703
704 i8k.ignore_dmi [HW] Continue probing hardware even if DMI data
705 indicates that the driver is running on unsupported
706 hardware.
707 i8k.force [HW] Activate i8k driver even if SMM BIOS signature
708 does not match list of supported models.
709 i8k.power_status
710 [HW] Report power status in /proc/i8k
711 (disabled by default)
712 i8k.restricted [HW] Allow controlling fans only if SYS_ADMIN
713 capability is set.
714
715 ibmmcascsi= [HW,MCA,SCSI] IBM MicroChannel SCSI adapter
716 See Documentation/mca.txt.
717
718 icn= [HW,ISDN]
719 Format: <io>[,<membase>[,<icn_id>[,<icn_id2>]]]
720
721 ide= [HW] (E)IDE subsystem
722 Format: ide=nodma or ide=doubler or ide=reverse
723 See Documentation/ide.txt.
724
725 ide?= [HW] (E)IDE subsystem
726 Format: ide?=noprobe or chipset specific parameters.
727 See Documentation/ide.txt.
728
729 idebus= [HW] (E)IDE subsystem - VLB/PCI bus speed
730 See Documentation/ide.txt.
731
732 idle= [X86]
733 Format: idle=poll or idle=mwait
734 Poll forces a polling idle loop that can slightly improves the performance
735 of waking up a idle CPU, but will use a lot of power and make the system
736 run hot. Not recommended.
737 idle=mwait. On systems which support MONITOR/MWAIT but the kernel chose
738 to not use it because it doesn't save as much power as a normal idle
739 loop use the MONITOR/MWAIT idle loop anyways. Performance should be the same
740 as idle=poll.
741
742 ignore_loglevel [KNL]
743 Ignore loglevel setting - this will print /all/
744 kernel messages to the console. Useful for debugging.
745
746 ihash_entries= [KNL]
747 Set number of hash buckets for inode cache.
748
749 in2000= [HW,SCSI]
750 See header of drivers/scsi/in2000.c.
751
752 init= [KNL]
753 Format: <full_path>
754 Run specified binary instead of /sbin/init as init
755 process.
756
757 initcall_debug [KNL] Trace initcalls as they are executed. Useful
758 for working out where the kernel is dying during
759 startup.
760
761 initrd= [BOOT] Specify the location of the initial ramdisk
762
763 inport.irq= [HW] Inport (ATI XL and Microsoft) busmouse driver
764 Format: <irq>
765
766 inttest= [IA64]
767
768 io7= [HW] IO7 for Marvel based alpha systems
769 See comment before marvel_specify_io7 in
770 arch/alpha/kernel/core_marvel.c.
771
772 ip= [IP_PNP]
773 See Documentation/nfsroot.txt.
774
775 ip2= [HW] Set IO/IRQ pairs for up to 4 IntelliPort boards
776 See comment before ip2_setup() in
777 drivers/char/ip2/ip2base.c.
778
779 ips= [HW,SCSI] Adaptec / IBM ServeRAID controller
780 See header of drivers/scsi/ips.c.
781
782 ports= [IP_VS_FTP] IPVS ftp helper module
783 Default is 21.
784 Up to 8 (IP_VS_APP_MAX_PORTS) ports
785 may be specified.
786 Format: <port>,<port>....
787
788 irqfixup [HW]
789 When an interrupt is not handled search all handlers
790 for it. Intended to get systems with badly broken
791 firmware running.
792
793 irqpoll [HW]
794 When an interrupt is not handled search all handlers
795 for it. Also check all handlers each timer
796 interrupt. Intended to get systems with badly broken
797 firmware running.
798
799 isapnp= [ISAPNP]
800 Format: <RDP>,<reset>,<pci_scan>,<verbosity>
801
802 isolcpus= [KNL,SMP] Isolate CPUs from the general scheduler.
803 Format:
804 <cpu number>,...,<cpu number>
805 or
806 <cpu number>-<cpu number> (must be a positive range in ascending order)
807 or a mixture
808 <cpu number>,...,<cpu number>-<cpu number>
809 This option can be used to specify one or more CPUs
810 to isolate from the general SMP balancing and scheduling
811 algorithms. The only way to move a process onto or off
812 an "isolated" CPU is via the CPU affinity syscalls.
813 <cpu number> begins at 0 and the maximum value is
814 "number of CPUs in system - 1".
815
816 This option is the preferred way to isolate CPUs. The
817 alternative -- manually setting the CPU mask of all
818 tasks in the system -- can cause problems and
819 suboptimal load balancer performance.
820
821 iucv= [HW,NET]
822
823 js= [HW,JOY] Analog joystick
824 See Documentation/input/joystick.txt.
825
826 kernelcore=nn[KMG] [KNL,X86-32,IA-64,PPC,X86-64] This parameter
827 specifies the amount of memory usable by the kernel
828 for non-movable allocations. The requested amount is
829 spread evenly throughout all nodes in the system. The
830 remaining memory in each node is used for Movable
831 pages. In the event, a node is too small to have both
832 kernelcore and Movable pages, kernelcore pages will
833 take priority and other nodes will have a larger number
834 of kernelcore pages. The Movable zone is used for the
835 allocation of pages that may be reclaimed or moved
836 by the page migration subsystem. This means that
837 HugeTLB pages may not be allocated from this zone.
838 Note that allocations like PTEs-from-HighMem still
839 use the HighMem zone if it exists, and the Normal
840 zone if it does not.
841
842 movablecore=nn[KMG] [KNL,X86-32,IA-64,PPC,X86-64] This parameter
843 is similar to kernelcore except it specifies the
844 amount of memory used for migratable allocations.
845 If both kernelcore and movablecore is specified,
846 then kernelcore will be at *least* the specified
847 value but may be more. If movablecore on its own
848 is specified, the administrator must be careful
849 that the amount of memory usable for all allocations
850 is not too small.
851
852 keepinitrd [HW,ARM]
853
854 kstack=N [X86-32,X86-64] Print N words from the kernel stack
855 in oops dumps.
856
857 l2cr= [PPC]
858
859 lapic [X86-32,APIC] Enable the local APIC even if BIOS
860 disabled it.
861
862 lapic_timer_c2_ok [X86-32,x86-64,APIC] trust the local apic timer in
863 C2 power state.
864
865 lasi= [HW,SCSI] PARISC LASI driver for the 53c700 chip
866 Format: addr:<io>,irq:<irq>
867
868 load_ramdisk= [RAM] List of ramdisks to load from floppy
869 See Documentation/ramdisk.txt.
870
871 lockd.nlm_grace_period=P [NFS] Assign grace period.
872 Format: <integer>
873
874 lockd.nlm_tcpport=N [NFS] Assign TCP port.
875 Format: <integer>
876
877 lockd.nlm_timeout=T [NFS] Assign timeout value.
878 Format: <integer>
879
880 lockd.nlm_udpport=M [NFS] Assign UDP port.
881 Format: <integer>
882
883 logibm.irq= [HW,MOUSE] Logitech Bus Mouse Driver
884 Format: <irq>
885
886 loglevel= All Kernel Messages with a loglevel smaller than the
887 console loglevel will be printed to the console. It can
888 also be changed with klogd or other programs. The
889 loglevels are defined as follows:
890
891 0 (KERN_EMERG) system is unusable
892 1 (KERN_ALERT) action must be taken immediately
893 2 (KERN_CRIT) critical conditions
894 3 (KERN_ERR) error conditions
895 4 (KERN_WARNING) warning conditions
896 5 (KERN_NOTICE) normal but significant condition
897 6 (KERN_INFO) informational
898 7 (KERN_DEBUG) debug-level messages
899
900 log_buf_len=n Sets the size of the printk ring buffer, in bytes.
901 Format: { n | nk | nM }
902 n must be a power of two. The default size
903 is set in the kernel config file.
904
905 lp=0 [LP] Specify parallel ports to use, e.g,
906 lp=port[,port...] lp=none,parport0 (lp0 not configured, lp1 uses
907 lp=reset first parallel port). 'lp=0' disables the
908 lp=auto printer driver. 'lp=reset' (which can be
909 specified in addition to the ports) causes
910 attached printers to be reset. Using
911 lp=port1,port2,... specifies the parallel ports
912 to associate lp devices with, starting with
913 lp0. A port specification may be 'none' to skip
914 that lp device, or a parport name such as
915 'parport0'. Specifying 'lp=auto' instead of a
916 port specification list means that device IDs
917 from each port should be examined, to see if
918 an IEEE 1284-compliant printer is attached; if
919 so, the driver will manage that printer.
920 See also header of drivers/char/lp.c.
921
922 lpj=n [KNL]
923 Sets loops_per_jiffy to given constant, thus avoiding
924 time-consuming boot-time autodetection (up to 250 ms per
925 CPU). 0 enables autodetection (default). To determine
926 the correct value for your kernel, boot with normal
927 autodetection and see what value is printed. Note that
928 on SMP systems the preset will be applied to all CPUs,
929 which is likely to cause problems if your CPUs need
930 significantly divergent settings. An incorrect value
931 will cause delays in the kernel to be wrong, leading to
932 unpredictable I/O errors and other breakage. Although
933 unlikely, in the extreme case this might damage your
934 hardware.
935
936 ltpc= [NET]
937 Format: <io>,<irq>,<dma>
938
939 mac5380= [HW,SCSI] Format:
940 <can_queue>,<cmd_per_lun>,<sg_tablesize>,<hostid>,<use_tags>
941
942 mac53c9x= [HW,SCSI] Format:
943 <num_esps>,<disconnect>,<nosync>,<can_queue>,<cmd_per_lun>,<sg_tablesize>,<hostid>,<use_tags>
944
945 machvec= [IA64] Force the use of a particular machine-vector
946 (machvec) in a generic kernel.
947 Example: machvec=hpzx1_swiotlb
948
949 max_loop= [LOOP] Maximum number of loopback devices that can
950 be mounted
951 Format: <1-256>
952
953 maxcpus= [SMP] Maximum number of processors that an SMP kernel
954 should make use of. maxcpus=n : n >= 0 limits the
955 kernel to using 'n' processors. n=0 is a special case,
956 it is equivalent to "nosmp", which also disables
957 the IO APIC.
958
959 max_addr=[KMG] [KNL,BOOT,ia64] All physical memory greater than or
960 equal to this physical address is ignored.
961
962 max_luns= [SCSI] Maximum number of LUNs to probe.
963 Should be between 1 and 2^32-1.
964
965 max_report_luns=
966 [SCSI] Maximum number of LUNs received.
967 Should be between 1 and 16384.
968
969 mca-pentium [BUGS=X86-32]
970
971 mcatest= [IA-64]
972
973 mce [X86-32] Machine Check Exception
974
975 md= [HW] RAID subsystems devices and level
976 See Documentation/md.txt.
977
978 mdacon= [MDA]
979 Format: <first>,<last>
980 Specifies range of consoles to be captured by the MDA.
981
982 mem=nn[KMG] [KNL,BOOT] Force usage of a specific amount of memory
983 Amount of memory to be used when the kernel is not able
984 to see the whole system memory or for test.
985 [X86-32] Use together with memmap= to avoid physical
986 address space collisions. Without memmap= PCI devices
987 could be placed at addresses belonging to unused RAM.
988
989 mem=nopentium [BUGS=X86-32] Disable usage of 4MB pages for kernel
990 memory.
991
992 memmap=exactmap [KNL,X86-32,X86_64] Enable setting of an exact
993 E820 memory map, as specified by the user.
994 Such memmap=exactmap lines can be constructed based on
995 BIOS output or other requirements. See the memmap=nn@ss
996 option description.
997
998 memmap=nn[KMG]@ss[KMG]
999 [KNL] Force usage of a specific region of memory
1000 Region of memory to be used, from ss to ss+nn.
1001
1002 memmap=nn[KMG]#ss[KMG]
1003 [KNL,ACPI] Mark specific memory as ACPI data.
1004 Region of memory to be used, from ss to ss+nn.
1005
1006 memmap=nn[KMG]$ss[KMG]
1007 [KNL,ACPI] Mark specific memory as reserved.
1008 Region of memory to be used, from ss to ss+nn.
1009
1010 meye.*= [HW] Set MotionEye Camera parameters
1011 See Documentation/video4linux/meye.txt.
1012
1013 mga= [HW,DRM]
1014
1015 mousedev.tap_time=
1016 [MOUSE] Maximum time between finger touching and
1017 leaving touchpad surface for touch to be considered
1018 a tap and be reported as a left button click (for
1019 touchpads working in absolute mode only).
1020 Format: <msecs>
1021 mousedev.xres= [MOUSE] Horizontal screen resolution, used for devices
1022 reporting absolute coordinates, such as tablets
1023 mousedev.yres= [MOUSE] Vertical screen resolution, used for devices
1024 reporting absolute coordinates, such as tablets
1025
1026 mpu401= [HW,OSS]
1027 Format: <io>,<irq>
1028
1029 MTD_Partition= [MTD]
1030 Format: <name>,<region-number>,<size>,<offset>
1031
1032 MTD_Region= [MTD] Format:
1033 <name>,<region-number>[,<base>,<size>,<buswidth>,<altbuswidth>]
1034
1035 mtdparts= [MTD]
1036 See drivers/mtd/cmdlinepart.c.
1037
1038 mtouchusb.raw_coordinates=
1039 [HW] Make the MicroTouch USB driver use raw coordinates
1040 ('y', default) or cooked coordinates ('n')
1041
1042 n2= [NET] SDL Inc. RISCom/N2 synchronous serial card
1043
1044 NCR_D700= [HW,SCSI]
1045 See header of drivers/scsi/NCR_D700.c.
1046
1047 ncr5380= [HW,SCSI]
1048
1049 ncr53c400= [HW,SCSI]
1050
1051 ncr53c400a= [HW,SCSI]
1052
1053 ncr53c406a= [HW,SCSI]
1054
1055 ncr53c8xx= [HW,SCSI]
1056
1057 netdev= [NET] Network devices parameters
1058 Format: <irq>,<io>,<mem_start>,<mem_end>,<name>
1059 Note that mem_start is often overloaded to mean
1060 something different and driver-specific.
1061 This usage is only documented in each driver source
1062 file if at all.
1063
1064 nfsaddrs= [NFS]
1065 See Documentation/nfsroot.txt.
1066
1067 nfsroot= [NFS] nfs root filesystem for disk-less boxes.
1068 See Documentation/nfsroot.txt.
1069
1070 nfs.callback_tcpport=
1071 [NFS] set the TCP port on which the NFSv4 callback
1072 channel should listen.
1073
1074 nfs.idmap_cache_timeout=
1075 [NFS] set the maximum lifetime for idmapper cache
1076 entries.
1077
1078 nmi_watchdog= [KNL,BUGS=X86-32] Debugging features for SMP kernels
1079
1080 no387 [BUGS=X86-32] Tells the kernel to use the 387 maths
1081 emulation library even if a 387 maths coprocessor
1082 is present.
1083
1084 noacpi [LIBATA] Disables use of ACPI in libata suspend/resume
1085 when set.
1086 Format: <int>
1087
1088 noaliencache [MM, NUMA, SLAB] Disables the allocation of alien
1089 caches in the slab allocator. Saves per-node memory,
1090 but will impact performance.
1091
1092 noalign [KNL,ARM]
1093
1094 noapic [SMP,APIC] Tells the kernel to not make use of any
1095 IOAPICs that may be present in the system.
1096
1097 noasync [HW,M68K] Disables async and sync negotiation for
1098 all devices.
1099
1100 nobats [PPC] Do not use BATs for mapping kernel lowmem
1101 on "Classic" PPC cores.
1102
1103 nocache [ARM]
1104
1105 nodelayacct [KNL] Disable per-task delay accounting
1106
1107 nodisconnect [HW,SCSI,M68K] Disables SCSI disconnects.
1108
1109 noexec [IA-64]
1110
1111 noexec [X86-32,X86-64]
1112 noexec=on: enable non-executable mappings (default)
1113 noexec=off: disable nn-executable mappings
1114
1115 nofxsr [BUGS=X86-32] Disables x86 floating point extended
1116 register save and restore. The kernel will only save
1117 legacy floating-point registers on task switch.
1118
1119 nohlt [BUGS=ARM]
1120
1121 no-hlt [BUGS=X86-32] Tells the kernel that the hlt
1122 instruction doesn't work correctly and not to
1123 use it.
1124
1125 nohalt [IA-64] Tells the kernel not to use the power saving
1126 function PAL_HALT_LIGHT when idle. This increases
1127 power-consumption. On the positive side, it reduces
1128 interrupt wake-up latency, which may improve performance
1129 in certain environments such as networked servers or
1130 real-time systems.
1131
1132 nohz= [KNL] Boottime enable/disable dynamic ticks
1133 Valid arguments: on, off
1134 Default: on
1135
1136 noirqbalance [X86-32,SMP,KNL] Disable kernel irq balancing
1137
1138 noirqdebug [X86-32] Disables the code which attempts to detect and
1139 disable unhandled interrupt sources.
1140
1141 no_timer_check [X86-32,X86_64,APIC] Disables the code which tests for
1142 broken timer IRQ sources.
1143
1144 noisapnp [ISAPNP] Disables ISA PnP code.
1145
1146 noinitrd [RAM] Tells the kernel not to load any configured
1147 initial RAM disk.
1148
1149 nointroute [IA-64]
1150
1151 nojitter [IA64] Disables jitter checking for ITC timers.
1152
1153 nolapic [X86-32,APIC] Do not enable or use the local APIC.
1154
1155 nolapic_timer [X86-32,APIC] Do not use the local APIC timer.
1156
1157 noltlbs [PPC] Do not use large page/tlb entries for kernel
1158 lowmem mapping on PPC40x.
1159
1160 nomca [IA-64] Disable machine check abort handling
1161
1162 nomce [X86-32] Machine Check Exception
1163
1164 noreplace-paravirt [X86-32,PV_OPS] Don't patch paravirt_ops
1165
1166 noreplace-smp [X86-32,SMP] Don't replace SMP instructions
1167 with UP alternatives
1168
1169 noresidual [PPC] Don't use residual data on PReP machines.
1170
1171 noresume [SWSUSP] Disables resume and restores original swap
1172 space.
1173
1174 no-scroll [VGA] Disables scrollback.
1175 This is required for the Braillex ib80-piezo Braille
1176 reader made by F.H. Papenmeier (Germany).
1177
1178 nosbagart [IA-64]
1179
1180 nosep [BUGS=X86-32] Disables x86 SYSENTER/SYSEXIT support.
1181
1182 nosmp [SMP] Tells an SMP kernel to act as a UP kernel,
1183 and disable the IO APIC. legacy for "maxcpus=0".
1184
1185 nosoftlockup [KNL] Disable the soft-lockup detector.
1186
1187 nosync [HW,M68K] Disables sync negotiation for all devices.
1188
1189 notsc [BUGS=X86-32] Disable Time Stamp Counter
1190
1191 nousb [USB] Disable the USB subsystem
1192
1193 nowb [ARM]
1194
1195 numa_zonelist_order= [KNL, BOOT] Select zonelist order for NUMA.
1196 one of ['zone', 'node', 'default'] can be specified
1197 This can be set from sysctl after boot.
1198 See Documentation/sysctl/vm.txt for details.
1199
1200 nr_uarts= [SERIAL] maximum number of UARTs to be registered.
1201
1202 opl3= [HW,OSS]
1203 Format: <io>
1204
1205 oprofile.timer= [HW]
1206 Use timer interrupt instead of performance counters
1207
1208 osst= [HW,SCSI] SCSI Tape Driver
1209 Format: <buffer_size>,<write_threshold>
1210 See also Documentation/scsi/st.txt.
1211
1212 panic= [KNL] Kernel behaviour on panic
1213 Format: <timeout>
1214
1215 parkbd.port= [HW] Parallel port number the keyboard adapter is
1216 connected to, default is 0.
1217 Format: <parport#>
1218 parkbd.mode= [HW] Parallel port keyboard adapter mode of operation,
1219 0 for XT, 1 for AT (default is AT).
1220 Format: <mode>
1221
1222 parport= [HW,PPT] Specify parallel ports. 0 disables.
1223 Format: { 0 | auto | 0xBBB[,IRQ[,DMA]] }
1224 Use 'auto' to force the driver to use any
1225 IRQ/DMA settings detected (the default is to
1226 ignore detected IRQ/DMA settings because of
1227 possible conflicts). You can specify the base
1228 address, IRQ, and DMA settings; IRQ and DMA
1229 should be numbers, or 'auto' (for using detected
1230 settings on that particular port), or 'nofifo'
1231 (to avoid using a FIFO even if it is detected).
1232 Parallel ports are assigned in the order they
1233 are specified on the command line, starting
1234 with parport0.
1235
1236 parport_init_mode= [HW,PPT]
1237 Configure VIA parallel port to operate in
1238 a specific mode. This is necessary on Pegasos
1239 computer where firmware has no options for setting
1240 up parallel port mode and sets it to spp.
1241 Currently this function knows 686a and 8231 chips.
1242 Format: [spp|ps2|epp|ecp|ecpepp]
1243
1244 pas2= [HW,OSS] Format:
1245 <io>,<irq>,<dma>,<dma16>,<sb_io>,<sb_irq>,<sb_dma>,<sb_dma16>
1246
1247 pas16= [HW,SCSI]
1248 See header of drivers/scsi/pas16.c.
1249
1250 pause_on_oops=
1251 Halt all CPUs after the first oops has been printed for
1252 the specified number of seconds. This is to be used if
1253 your oopses keep scrolling off the screen.
1254
1255 pcbit= [HW,ISDN]
1256
1257 pcd. [PARIDE]
1258 See header of drivers/block/paride/pcd.c.
1259 See also Documentation/paride.txt.
1260
1261 pci=option[,option...] [PCI] various PCI subsystem options:
1262 off [X86-32] don't probe for the PCI bus
1263 bios [X86-32] force use of PCI BIOS, don't access
1264 the hardware directly. Use this if your machine
1265 has a non-standard PCI host bridge.
1266 nobios [X86-32] disallow use of PCI BIOS, only direct
1267 hardware access methods are allowed. Use this
1268 if you experience crashes upon bootup and you
1269 suspect they are caused by the BIOS.
1270 conf1 [X86-32] Force use of PCI Configuration
1271 Mechanism 1.
1272 conf2 [X86-32] Force use of PCI Configuration
1273 Mechanism 2.
1274 noaer [PCIE] If the PCIEAER kernel config parameter is
1275 enabled, this kernel boot option can be used to
1276 disable the use of PCIE advanced error reporting.
1277 nommconf [X86-32,X86_64] Disable use of MMCONFIG for PCI
1278 Configuration
1279 nomsi [MSI] If the PCI_MSI kernel config parameter is
1280 enabled, this kernel boot option can be used to
1281 disable the use of MSI interrupts system-wide.
1282 nosort [X86-32] Don't sort PCI devices according to
1283 order given by the PCI BIOS. This sorting is
1284 done to get a device order compatible with
1285 older kernels.
1286 biosirq [X86-32] Use PCI BIOS calls to get the interrupt
1287 routing table. These calls are known to be buggy
1288 on several machines and they hang the machine
1289 when used, but on other computers it's the only
1290 way to get the interrupt routing table. Try
1291 this option if the kernel is unable to allocate
1292 IRQs or discover secondary PCI buses on your
1293 motherboard.
1294 rom [X86-32] Assign address space to expansion ROMs.
1295 Use with caution as certain devices share
1296 address decoders between ROMs and other
1297 resources.
1298 irqmask=0xMMMM [X86-32] Set a bit mask of IRQs allowed to be
1299 assigned automatically to PCI devices. You can
1300 make the kernel exclude IRQs of your ISA cards
1301 this way.
1302 pirqaddr=0xAAAAA [X86-32] Specify the physical address
1303 of the PIRQ table (normally generated
1304 by the BIOS) if it is outside the
1305 F0000h-100000h range.
1306 lastbus=N [X86-32] Scan all buses thru bus #N. Can be
1307 useful if the kernel is unable to find your
1308 secondary buses and you want to tell it
1309 explicitly which ones they are.
1310 assign-busses [X86-32] Always assign all PCI bus
1311 numbers ourselves, overriding
1312 whatever the firmware may have done.
1313 usepirqmask [X86-32] Honor the possible IRQ mask stored
1314 in the BIOS $PIR table. This is needed on
1315 some systems with broken BIOSes, notably
1316 some HP Pavilion N5400 and Omnibook XE3
1317 notebooks. This will have no effect if ACPI
1318 IRQ routing is enabled.
1319 noacpi [X86-32] Do not use ACPI for IRQ routing
1320 or for PCI scanning.
1321 use_crs [X86-32] Use _CRS for PCI resource
1322 allocation.
1323 routeirq Do IRQ routing for all PCI devices.
1324 This is normally done in pci_enable_device(),
1325 so this option is a temporary workaround
1326 for broken drivers that don't call it.
1327 firmware [ARM] Do not re-enumerate the bus but instead
1328 just use the configuration from the
1329 bootloader. This is currently used on
1330 IXP2000 systems where the bus has to be
1331 configured a certain way for adjunct CPUs.
1332 noearly [X86] Don't do any early type 1 scanning.
1333 This might help on some broken boards which
1334 machine check when some devices' config space
1335 is read. But various workarounds are disabled
1336 and some IOMMU drivers will not work.
1337 bfsort Sort PCI devices into breadth-first order.
1338 This sorting is done to get a device
1339 order compatible with older (<= 2.4) kernels.
1340 nobfsort Don't sort PCI devices into breadth-first order.
1341 cbiosize=nn[KMG] The fixed amount of bus space which is
1342 reserved for the CardBus bridge's IO window.
1343 The default value is 256 bytes.
1344 cbmemsize=nn[KMG] The fixed amount of bus space which is
1345 reserved for the CardBus bridge's memory
1346 window. The default value is 64 megabytes.
1347
1348 pcmv= [HW,PCMCIA] BadgePAD 4
1349
1350 pd. [PARIDE]
1351 See Documentation/paride.txt.
1352
1353 pdcchassis= [PARISC,HW] Disable/Enable PDC Chassis Status codes at
1354 boot time.
1355 Format: { 0 | 1 }
1356 See arch/parisc/kernel/pdc_chassis.c
1357
1358 pf. [PARIDE]
1359 See Documentation/paride.txt.
1360
1361 pg. [PARIDE]
1362 See Documentation/paride.txt.
1363
1364 pirq= [SMP,APIC] Manual mp-table setup
1365 See Documentation/i386/IO-APIC.txt.
1366
1367 plip= [PPT,NET] Parallel port network link
1368 Format: { parport<nr> | timid | 0 }
1369 See also Documentation/parport.txt.
1370
1371 pnpacpi= [ACPI]
1372 { off }
1373
1374 pnpbios= [ISAPNP]
1375 { on | off | curr | res | no-curr | no-res }
1376
1377 pnp_reserve_irq=
1378 [ISAPNP] Exclude IRQs for the autoconfiguration
1379
1380 pnp_reserve_dma=
1381 [ISAPNP] Exclude DMAs for the autoconfiguration
1382
1383 pnp_reserve_io= [ISAPNP] Exclude I/O ports for the autoconfiguration
1384 Ranges are in pairs (I/O port base and size).
1385
1386 pnp_reserve_mem=
1387 [ISAPNP] Exclude memory regions for the
1388 autoconfiguration.
1389 Ranges are in pairs (memory base and size).
1390
1391 print-fatal-signals=
1392 [KNL] debug: print fatal signals
1393 print-fatal-signals=1: print segfault info to
1394 the kernel console.
1395 default: off.
1396
1397 printk.time= Show timing data prefixed to each printk message line
1398 Format: <bool> (1/Y/y=enable, 0/N/n=disable)
1399
1400 profile= [KNL] Enable kernel profiling via /proc/profile
1401 Format: [schedule,]<number>
1402 Param: "schedule" - profile schedule points.
1403 Param: <number> - step/bucket size as a power of 2 for
1404 statistical time based profiling.
1405 Param: "sleep" - profile D-state sleeping (millisecs)
1406
1407 processor.max_cstate= [HW,ACPI]
1408 Limit processor to maximum C-state
1409 max_cstate=9 overrides any DMI blacklist limit.
1410
1411 processor.nocst [HW,ACPI]
1412 Ignore the _CST method to determine C-states,
1413 instead using the legacy FADT method
1414
1415 prompt_ramdisk= [RAM] List of RAM disks to prompt for floppy disk
1416 before loading.
1417 See Documentation/ramdisk.txt.
1418
1419 psmouse.proto= [HW,MOUSE] Highest PS2 mouse protocol extension to
1420 probe for; one of (bare|imps|exps|lifebook|any).
1421 psmouse.rate= [HW,MOUSE] Set desired mouse report rate, in reports
1422 per second.
1423 psmouse.resetafter= [HW,MOUSE]
1424 Try to reset the device after so many bad packets
1425 (0 = never).
1426 psmouse.resolution=
1427 [HW,MOUSE] Set desired mouse resolution, in dpi.
1428 psmouse.smartscroll=
1429 [HW,MOUSE] Controls Logitech smartscroll autorepeat.
1430 0 = disabled, 1 = enabled (default).
1431
1432 pss= [HW,OSS] Personal Sound System (ECHO ESC614)
1433 Format:
1434 <io>,<mss_io>,<mss_irq>,<mss_dma>,<mpu_io>,<mpu_irq>
1435
1436 pt. [PARIDE]
1437 See Documentation/paride.txt.
1438
1439 quiet [KNL] Disable most log messages
1440
1441 r128= [HW,DRM]
1442
1443 raid= [HW,RAID]
1444 See Documentation/md.txt.
1445
1446 ramdisk= [RAM] Sizes of RAM disks in kilobytes [deprecated]
1447 See Documentation/ramdisk.txt.
1448
1449 ramdisk_blocksize= [RAM]
1450 See Documentation/ramdisk.txt.
1451
1452 ramdisk_size= [RAM] Sizes of RAM disks in kilobytes
1453 New name for the ramdisk parameter.
1454 See Documentation/ramdisk.txt.
1455
1456 rcu.blimit= [KNL,BOOT] Set maximum number of finished
1457 RCU callbacks to process in one batch.
1458
1459 rcu.qhimark= [KNL,BOOT] Set threshold of queued
1460 RCU callbacks over which batch limiting is disabled.
1461
1462 rcu.qlowmark= [KNL,BOOT] Set threshold of queued
1463 RCU callbacks below which batch limiting is re-enabled.
1464
1465 rdinit= [KNL]
1466 Format: <full_path>
1467 Run specified binary instead of /init from the ramdisk,
1468 used for early userspace startup. See initrd.
1469
1470 reboot= [BUGS=X86-32,BUGS=ARM,BUGS=IA-64] Rebooting mode
1471 Format: <reboot_mode>[,<reboot_mode2>[,...]]
1472 See arch/*/kernel/reboot.c or arch/*/kernel/process.c
1473
1474 reserve= [KNL,BUGS] Force the kernel to ignore some iomem area
1475
1476 reservetop= [X86-32]
1477 Format: nn[KMG]
1478 Reserves a hole at the top of the kernel virtual
1479 address space.
1480
1481 reset_devices [KNL] Force drivers to reset the underlying device
1482 during initialization.
1483
1484 resume= [SWSUSP]
1485 Specify the partition device for software suspend
1486
1487 resume_offset= [SWSUSP]
1488 Specify the offset from the beginning of the partition
1489 given by "resume=" at which the swap header is located,
1490 in <PAGE_SIZE> units (needed only for swap files).
1491 See Documentation/power/swsusp-and-swap-files.txt
1492
1493 retain_initrd [RAM] Keep initrd memory after extraction
1494
1495 rhash_entries= [KNL,NET]
1496 Set number of hash buckets for route cache
1497
1498 riscom8= [HW,SERIAL]
1499 Format: <io_board1>[,<io_board2>[,...<io_boardN>]]
1500
1501 ro [KNL] Mount root device read-only on boot
1502
1503 root= [KNL] Root filesystem
1504
1505 rootdelay= [KNL] Delay (in seconds) to pause before attempting to
1506 mount the root filesystem
1507
1508 rootflags= [KNL] Set root filesystem mount option string
1509
1510 rootfstype= [KNL] Set root filesystem type
1511
1512 rootwait [KNL] Wait (indefinitely) for root device to show up.
1513 Useful for devices that are detected asynchronously
1514 (e.g. USB and MMC devices).
1515
1516 rw [KNL] Mount root device read-write on boot
1517
1518 S [KNL] Run init in single mode
1519
1520 sa1100ir [NET]
1521 See drivers/net/irda/sa1100_ir.c.
1522
1523 sb= [HW,OSS]
1524 Format: <io>,<irq>,<dma>,<dma2>
1525
1526 sbni= [NET] Granch SBNI12 leased line adapter
1527
1528 sc1200wdt= [HW,WDT] SC1200 WDT (watchdog) driver
1529 Format: <io>[,<timeout>[,<isapnp>]]
1530
1531 scsi_debug_*= [SCSI]
1532 See drivers/scsi/scsi_debug.c.
1533
1534 scsi_default_dev_flags=
1535 [SCSI] SCSI default device flags
1536 Format: <integer>
1537
1538 scsi_dev_flags= [SCSI] Black/white list entry for vendor and model
1539 Format: <vendor>:<model>:<flags>
1540 (flags are integer value)
1541
1542 scsi_logging= [SCSI]
1543
1544 scsi_mod.scan= [SCSI] sync (default) scans SCSI busses as they are
1545 discovered. async scans them in kernel threads,
1546 allowing boot to proceed. none ignores them, expecting
1547 user space to do the scan.
1548
1549 selinux [SELINUX] Disable or enable SELinux at boot time.
1550 Format: { "0" | "1" }
1551 See security/selinux/Kconfig help text.
1552 0 -- disable.
1553 1 -- enable.
1554 Default value is set via kernel config option.
1555 If enabled at boot time, /selinux/disable can be used
1556 later to disable prior to initial policy load.
1557
1558 selinux_compat_net =
1559 [SELINUX] Set initial selinux_compat_net flag value.
1560 Format: { "0" | "1" }
1561 0 -- use new secmark-based packet controls
1562 1 -- use legacy packet controls
1563 Default value is 0 (preferred).
1564 Value can be changed at runtime via
1565 /selinux/compat_net.
1566
1567 serialnumber [BUGS=X86-32]
1568
1569 sg_def_reserved_size= [SCSI]
1570
1571 shapers= [NET]
1572 Maximal number of shapers.
1573
1574 sim710= [SCSI,HW]
1575 See header of drivers/scsi/sim710.c.
1576
1577 simeth= [IA-64]
1578 simscsi=
1579
1580 slram= [HW,MTD]
1581
1582 slub_debug[=options[,slabs]] [MM, SLUB]
1583 Enabling slub_debug allows one to determine the
1584 culprit if slab objects become corrupted. Enabling
1585 slub_debug can create guard zones around objects and
1586 may poison objects when not in use. Also tracks the
1587 last alloc / free. For more information see
1588 Documentation/vm/slub.txt.
1589
1590 slub_max_order= [MM, SLUB]
1591 Determines the maximum allowed order for slabs.
1592 A high setting may cause OOMs due to memory
1593 fragmentation. For more information see
1594 Documentation/vm/slub.txt.
1595
1596 slub_min_objects= [MM, SLUB]
1597 The minimum number of objects per slab. SLUB will
1598 increase the slab order up to slub_max_order to
1599 generate a sufficiently large slab able to contain
1600 the number of objects indicated. The higher the number
1601 of objects the smaller the overhead of tracking slabs
1602 and the less frequently locks need to be acquired.
1603 For more information see Documentation/vm/slub.txt.
1604
1605 slub_min_order= [MM, SLUB]
1606 Determines the mininum page order for slabs. Must be
1607 lower than slub_max_order.
1608 For more information see Documentation/vm/slub.txt.
1609
1610 slub_nomerge [MM, SLUB]
1611 Disable merging of slabs with similar size. May be
1612 necessary if there is some reason to distinguish
1613 allocs to different slabs. Debug options disable
1614 merging on their own.
1615 For more information see Documentation/vm/slub.txt.
1616
1617 smart2= [HW]
1618 Format: <io1>[,<io2>[,...,<io8>]]
1619
1620 smp-alt-once [X86-32,SMP] On a hotplug CPU system, only
1621 attempt to substitute SMP alternatives once at boot.
1622
1623 smsc-ircc2.nopnp [HW] Don't use PNP to discover SMC devices
1624 smsc-ircc2.ircc_cfg= [HW] Device configuration I/O port
1625 smsc-ircc2.ircc_sir= [HW] SIR base I/O port
1626 smsc-ircc2.ircc_fir= [HW] FIR base I/O port
1627 smsc-ircc2.ircc_irq= [HW] IRQ line
1628 smsc-ircc2.ircc_dma= [HW] DMA channel
1629 smsc-ircc2.ircc_transceiver= [HW] Transceiver type:
1630 0: Toshiba Satellite 1800 (GP data pin select)
1631 1: Fast pin select (default)
1632 2: ATC IRMode
1633
1634 snd-ad1816a= [HW,ALSA]
1635
1636 snd-ad1848= [HW,ALSA]
1637
1638 snd-ali5451= [HW,ALSA]
1639
1640 snd-als100= [HW,ALSA]
1641
1642 snd-als4000= [HW,ALSA]
1643
1644 snd-azt2320= [HW,ALSA]
1645
1646 snd-cmi8330= [HW,ALSA]
1647
1648 snd-cmipci= [HW,ALSA]
1649
1650 snd-cs4231= [HW,ALSA]
1651
1652 snd-cs4232= [HW,ALSA]
1653
1654 snd-cs4236= [HW,ALSA]
1655
1656 snd-cs4281= [HW,ALSA]
1657
1658 snd-cs46xx= [HW,ALSA]
1659
1660 snd-dt019x= [HW,ALSA]
1661
1662 snd-dummy= [HW,ALSA]
1663
1664 snd-emu10k1= [HW,ALSA]
1665
1666 snd-ens1370= [HW,ALSA]
1667
1668 snd-ens1371= [HW,ALSA]
1669
1670 snd-es968= [HW,ALSA]
1671
1672 snd-es1688= [HW,ALSA]
1673
1674 snd-es18xx= [HW,ALSA]
1675
1676 snd-es1938= [HW,ALSA]
1677
1678 snd-es1968= [HW,ALSA]
1679
1680 snd-fm801= [HW,ALSA]
1681
1682 snd-gusclassic= [HW,ALSA]
1683
1684 snd-gusextreme= [HW,ALSA]
1685
1686 snd-gusmax= [HW,ALSA]
1687
1688 snd-hdsp= [HW,ALSA]
1689
1690 snd-ice1712= [HW,ALSA]
1691
1692 snd-intel8x0= [HW,ALSA]
1693
1694 snd-interwave= [HW,ALSA]
1695
1696 snd-interwave-stb=
1697 [HW,ALSA]
1698
1699 snd-korg1212= [HW,ALSA]
1700
1701 snd-maestro3= [HW,ALSA]
1702
1703 snd-mpu401= [HW,ALSA]
1704
1705 snd-mtpav= [HW,ALSA]
1706
1707 snd-nm256= [HW,ALSA]
1708
1709 snd-opl3sa2= [HW,ALSA]
1710
1711 snd-opti92x-ad1848=
1712 [HW,ALSA]
1713
1714 snd-opti92x-cs4231=
1715 [HW,ALSA]
1716
1717 snd-opti93x= [HW,ALSA]
1718
1719 snd-pmac= [HW,ALSA]
1720
1721 snd-rme32= [HW,ALSA]
1722
1723 snd-rme96= [HW,ALSA]
1724
1725 snd-rme9652= [HW,ALSA]
1726
1727 snd-sb8= [HW,ALSA]
1728
1729 snd-sb16= [HW,ALSA]
1730
1731 snd-sbawe= [HW,ALSA]
1732
1733 snd-serial= [HW,ALSA]
1734
1735 snd-sgalaxy= [HW,ALSA]
1736
1737 snd-sonicvibes= [HW,ALSA]
1738
1739 snd-sun-amd7930=
1740 [HW,ALSA]
1741
1742 snd-sun-cs4231= [HW,ALSA]
1743
1744 snd-trident= [HW,ALSA]
1745
1746 snd-usb-audio= [HW,ALSA,USB]
1747
1748 snd-via82xx= [HW,ALSA]
1749
1750 snd-virmidi= [HW,ALSA]
1751
1752 snd-wavefront= [HW,ALSA]
1753
1754 snd-ymfpci= [HW,ALSA]
1755
1756 sonypi.*= [HW] Sony Programmable I/O Control Device driver
1757 See Documentation/sonypi.txt
1758
1759 specialix= [HW,SERIAL] Specialix multi-serial port adapter
1760 See Documentation/specialix.txt.
1761
1762 spia_io_base= [HW,MTD]
1763 spia_fio_base=
1764 spia_pedr=
1765 spia_peddr=
1766
1767 sscape= [HW,OSS]
1768 Format: <io>,<irq>,<dma>,<mpu_io>,<mpu_irq>
1769
1770 st= [HW,SCSI] SCSI tape parameters (buffers, etc.)
1771 See Documentation/scsi/st.txt.
1772
1773 st0x= [HW,SCSI]
1774 See header of drivers/scsi/seagate.c.
1775
1776 sti= [PARISC,HW]
1777 Format: <num>
1778 Set the STI (builtin display/keyboard on the HP-PARISC
1779 machines) console (graphic card) which should be used
1780 as the initial boot-console.
1781 See also comment in drivers/video/console/sticore.c.
1782
1783 sti_font= [HW]
1784 See comment in drivers/video/console/sticore.c.
1785
1786 stifb= [HW]
1787 Format: bpp:<bpp1>[:<bpp2>[:<bpp3>...]]
1788
1789 sunrpc.pool_mode=
1790 [NFS]
1791 Control how the NFS server code allocates CPUs to
1792 service thread pools. Depending on how many NICs
1793 you have and where their interrupts are bound, this
1794 option will affect which CPUs will do NFS serving.
1795 Note: this parameter cannot be changed while the
1796 NFS server is running.
1797
1798 auto the server chooses an appropriate mode
1799 automatically using heuristics
1800 global a single global pool contains all CPUs
1801 percpu one pool for each CPU
1802 pernode one pool for each NUMA node (equivalent
1803 to global on non-NUMA machines)
1804
1805 swiotlb= [IA-64] Number of I/O TLB slabs
1806
1807 switches= [HW,M68k]
1808
1809 sym53c416= [HW,SCSI]
1810 See header of drivers/scsi/sym53c416.c.
1811
1812 sysrq_always_enabled
1813 [KNL]
1814 Ignore sysrq setting - this boot parameter will
1815 neutralize any effect of /proc/sys/kernel/sysrq.
1816 Useful for debugging.
1817
1818 t128= [HW,SCSI]
1819 See header of drivers/scsi/t128.c.
1820
1821 tdfx= [HW,DRM]
1822
1823 thash_entries= [KNL,NET]
1824 Set number of hash buckets for TCP connection
1825
1826 thermal.act= [HW,ACPI]
1827 -1: disable all active trip points in all thermal zones
1828 <degrees C>: override all lowest active trip points
1829
1830 thermal.crt= [HW,ACPI]
1831 -1: disable all critical trip points in all thermal zones
1832 <degrees C>: lower all critical trip points
1833
1834 thermal.nocrt= [HW,ACPI]
1835 Set to disable actions on ACPI thermal zone
1836 critical and hot trip points.
1837
1838 thermal.off= [HW,ACPI]
1839 1: disable ACPI thermal control
1840
1841 thermal.psv= [HW,ACPI]
1842 -1: disable all passive trip points
1843 <degrees C>: override all passive trip points to this value
1844
1845 thermal.tzp= [HW,ACPI]
1846 Specify global default ACPI thermal zone polling rate
1847 <deci-seconds>: poll all this frequency
1848 0: no polling (default)
1849
1850 time Show timing data prefixed to each printk message line
1851 [deprecated, see 'printk.time']
1852
1853 tipar.timeout= [HW,PPT]
1854 Set communications timeout in tenths of a second
1855 (default 15).
1856
1857 tipar.delay= [HW,PPT]
1858 Set inter-bit delay in microseconds (default 10).
1859
1860 tmc8xx= [HW,SCSI]
1861 See header of drivers/scsi/seagate.c.
1862
1863 tmscsim= [HW,SCSI]
1864 See comment before function dc390_setup() in
1865 drivers/scsi/tmscsim.c.
1866
1867 tp720= [HW,PS2]
1868
1869 trix= [HW,OSS] MediaTrix AudioTrix Pro
1870 Format:
1871 <io>,<irq>,<dma>,<dma2>,<sb_io>,<sb_irq>,<sb_dma>,<mpu_io>,<mpu_irq>
1872
1873 tsdev.xres= [TS] Horizontal screen resolution.
1874 tsdev.yres= [TS] Vertical screen resolution.
1875
1876 turbografx.map[2|3]= [HW,JOY]
1877 TurboGraFX parallel port interface
1878 Format:
1879 <port#>,<js1>,<js2>,<js3>,<js4>,<js5>,<js6>,<js7>
1880 See also Documentation/input/joystick-parport.txt
1881
1882 u14-34f= [HW,SCSI] UltraStor 14F/34F SCSI host adapter
1883 See header of drivers/scsi/u14-34f.c.
1884
1885 uart401= [HW,OSS]
1886 Format: <io>,<irq>
1887
1888 uart6850= [HW,OSS]
1889 Format: <io>,<irq>
1890
1891 uhci-hcd.ignore_oc=
1892 [USB] Ignore overcurrent events (default N).
1893 Some badly-designed motherboards generate lots of
1894 bogus events, for ports that aren't wired to
1895 anything. Set this parameter to avoid log spamming.
1896 Note that genuine overcurrent events won't be
1897 reported either.
1898
1899 usbcore.autosuspend=
1900 [USB] The autosuspend time delay (in seconds) used
1901 for newly-detected USB devices (default 2). This
1902 is the time required before an idle device will be
1903 autosuspended. Devices for which the delay is set
1904 to a negative value won't be autosuspended at all.
1905
1906 usbhid.mousepoll=
1907 [USBHID] The interval which mice are to be polled at.
1908
1909 vdso= [X86-32,SH,x86-64]
1910 vdso=2: enable compat VDSO (default with COMPAT_VDSO)
1911 vdso=1: enable VDSO (default)
1912 vdso=0: disable VDSO mapping
1913
1914 vector= [IA-64,SMP]
1915 vector=percpu: enable percpu vector domain
1916
1917 video= [FB] Frame buffer configuration
1918 See Documentation/fb/modedb.txt.
1919
1920 vga= [BOOT,X86-32] Select a particular video mode
1921 See Documentation/i386/boot.txt and
1922 Documentation/svga.txt.
1923 Use vga=ask for menu.
1924 This is actually a boot loader parameter; the value is
1925 passed to the kernel using a special protocol.
1926
1927 vmalloc=nn[KMG] [KNL,BOOT] Forces the vmalloc area to have an exact
1928 size of <nn>. This can be used to increase the
1929 minimum size (128MB on x86). It can also be used to
1930 decrease the size and leave more room for directly
1931 mapped kernel RAM.
1932
1933 vmhalt= [KNL,S390] Perform z/VM CP command after system halt.
1934 Format: <command>
1935
1936 vmpanic= [KNL,S390] Perform z/VM CP command after kernel panic.
1937 Format: <command>
1938
1939 vmpoff= [KNL,S390] Perform z/VM CP command after power off.
1940 Format: <command>
1941
1942 waveartist= [HW,OSS]
1943 Format: <io>,<irq>,<dma>,<dma2>
1944
1945 wd33c93= [HW,SCSI]
1946 See header of drivers/scsi/wd33c93.c.
1947
1948 wd7000= [HW,SCSI]
1949 See header of drivers/scsi/wd7000.c.
1950
1951 wdt= [WDT] Watchdog
1952 See Documentation/watchdog/wdt.txt.
1953
1954 xd= [HW,XT] Original XT pre-IDE (RLL encoded) disks.
1955 xd_geo= See header of drivers/block/xd.c.
1956
1957 xirc2ps_cs= [NET,PCMCIA]
1958 Format:
1959 <irq>,<irq_mask>,<io>,<full_duplex>,<do_sound>,<lockup_hack>[,<irq2>[,<irq3>[,<irq4>]]]
1960
1961 norandmaps Don't use address space randomization
1962 Equivalent to echo 0 > /proc/sys/kernel/randomize_va_space
1963
1964 unwind_debug=N N > 0 will enable dwarf2 unwinder debugging
1965 This is useful to get more information why
1966 you got a "dwarf2 unwinder stuck"
1967
1968 ______________________________________________________________________
1969
1970 TODO:
1971
1972 Add documentation for ALSA options.
1973 Add more DRM drivers.