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1 Kernel Parameters
2 ~~~~~~~~~~~~~~~~~
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.
9 Module parameters for loadable modules are specified only as the
10 parameter name with optional '=' and value as appropriate, such as:
12 modprobe usbcore blinkenlights=1
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:
18 usbcore.blinkenlights=1
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}".
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:
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 AVR32 AVR32 architecture is enabled.
38 AX25 Appropriate AX.25 support is enabled.
39 BLACKFIN Blackfin architecture is enabled.
40 DRM Direct Rendering Management support is enabled.
41 EDD BIOS Enhanced Disk Drive Services (EDD) is enabled
42 EFI EFI Partitioning (GPT) is enabled
43 EIDE EIDE/ATAPI support is enabled.
44 FB The frame buffer device is enabled.
45 HW Appropriate hardware is enabled.
46 IA-64 IA-64 architecture is enabled.
47 IOSCHED More than one I/O scheduler is enabled.
48 IP_PNP IP DHCP, BOOTP, or RARP is enabled.
49 ISAPNP ISA PnP code is enabled.
50 ISDN Appropriate ISDN support is enabled.
51 JOY Appropriate joystick support is enabled.
52 LIBATA Libata driver is enabled
53 LP Printer support is enabled.
54 LOOP Loopback device support is enabled.
55 M68k M68k architecture is enabled.
56 These options have more detailed description inside of
57 Documentation/m68k/kernel-options.txt.
58 MCA MCA bus support is enabled.
59 MDA MDA console support is enabled.
60 MOUSE Appropriate mouse support is enabled.
61 MSI Message Signaled Interrupts (PCI).
62 MTD MTD (Memory Technology Device) support is enabled.
63 NET Appropriate network support is enabled.
64 NUMA NUMA support is enabled.
65 GENERIC_TIME The generic timeofday code is enabled.
66 NFS Appropriate NFS support is enabled.
67 OSS OSS sound support is enabled.
68 PV_OPS A paravirtualized kernel is enabled.
69 PARIDE The ParIDE (parallel port IDE) subsystem is enabled.
70 PARISC The PA-RISC architecture is enabled.
71 PCI PCI bus support is enabled.
72 PCIE PCI Express support is enabled.
73 PCMCIA The PCMCIA subsystem is enabled.
74 PNP Plug & Play support is enabled.
75 PPC PowerPC architecture is enabled.
76 PPT Parallel port support is enabled.
77 PS2 Appropriate PS/2 support is enabled.
78 RAM RAM disk support is enabled.
79 ROOTPLUG The example Root Plug LSM is enabled.
80 S390 S390 architecture is enabled.
81 SCSI Appropriate SCSI support is enabled.
82 A lot of drivers has their options described inside of
83 Documentation/scsi/.
84 SECURITY Different security models are enabled.
85 SELINUX SELinux support is enabled.
86 SERIAL Serial support is enabled.
87 SH SuperH architecture is enabled.
88 SMP The kernel is an SMP kernel.
89 SPARC Sparc architecture is enabled.
90 SWSUSP Software suspend is enabled.
91 TS Appropriate touchscreen support is enabled.
92 USB USB support is enabled.
93 USBHID USB Human Interface Device support is enabled.
94 V4L Video For Linux support is enabled.
95 VGA The VGA console has been enabled.
96 VT Virtual terminal support is enabled.
97 WDT Watchdog support is enabled.
98 XT IBM PC/XT MFM hard disk support is enabled.
99 X86-32 X86-32, aka i386 architecture is enabled.
100 X86-64 X86-64 architecture is enabled.
101 More X86-64 boot options can be found in
102 Documentation/x86_64/boot-options.txt .
104 In addition, the following text indicates that the option:
106 BUGS= Relates to possible processor bugs on the said processor.
107 KNL Is a kernel start-up parameter.
108 BOOT Is a boot loader parameter.
110 Parameters denoted with BOOT are actually interpreted by the boot
111 loader, and have no meaning to the kernel directly.
112 Do not modify the syntax of boot loader parameters without extreme
113 need or coordination with <Documentation/i386/boot.txt>.
115 There are also arch-specific kernel-parameters not documented here.
116 See for example <Documentation/x86_64/boot-options.txt>.
118 Note that ALL kernel parameters listed below are CASE SENSITIVE, and that
119 a trailing = on the name of any parameter states that that parameter will
120 be entered as an environment variable, whereas its absence indicates that
121 it will appear as a kernel argument readable via /proc/cmdline by programs
122 running once the system is up.
124 The number of kernel parameters is not limited, but the length of the
125 complete command line (parameters including spaces etc.) is limited to
126 a fixed number of characters. This limit depends on the architecture
127 and is between 256 and 4096 characters. It is defined in the file
128 ./include/asm/setup.h as COMMAND_LINE_SIZE.
131 acpi= [HW,ACPI,X86-64,i386]
132 Advanced Configuration and Power Interface
133 Format: { force | off | ht | strict | noirq }
134 force -- enable ACPI if default was off
135 off -- disable ACPI if default was on
136 noirq -- do not use ACPI for IRQ routing
137 ht -- run only enough ACPI to enable Hyper Threading
138 strict -- Be less tolerant of platforms that are not
139 strictly ACPI specification compliant.
141 See also Documentation/pm.txt, pci=noacpi
143 acpi_apic_instance= [ACPI, IOAPIC]
144 Format: <int>
145 2: use 2nd APIC table, if available
146 1,0: use 1st APIC table
147 default: 0
149 acpi_sleep= [HW,ACPI] Sleep options
150 Format: { s3_bios, s3_mode }
151 See Documentation/power/video.txt
153 acpi_sci= [HW,ACPI] ACPI System Control Interrupt trigger mode
154 Format: { level | edge | high | low }
156 acpi_irq_balance [HW,ACPI]
157 ACPI will balance active IRQs
158 default in APIC mode
160 acpi_irq_nobalance [HW,ACPI]
161 ACPI will not move active IRQs (default)
162 default in PIC mode
164 acpi_irq_pci= [HW,ACPI] If irq_balance, clear listed IRQs for
165 use by PCI
166 Format: <irq>,<irq>...
168 acpi_irq_isa= [HW,ACPI] If irq_balance, mark listed IRQs used by ISA
169 Format: <irq>,<irq>...
171 acpi_no_auto_ssdt [HW,ACPI] Disable automatic loading of SSDT
173 acpi_os_name= [HW,ACPI] Tell ACPI BIOS the name of the OS
174 Format: To spoof as Windows 98: ="Microsoft Windows"
176 acpi_osi= [HW,ACPI] Modify list of supported OS interface strings
177 acpi_osi="string1" # add string1 -- only one string
178 acpi_osi="!string2" # remove built-in string2
179 acpi_osi= # disable all strings
181 acpi_serialize [HW,ACPI] force serialization of AML methods
183 acpi_skip_timer_override [HW,ACPI]
184 Recognize and ignore IRQ0/pin2 Interrupt Override.
185 For broken nForce2 BIOS resulting in XT-PIC timer.
186 acpi_use_timer_override [HW,ACPI}
187 Use timer override. For some broken Nvidia NF5 boards
188 that require a timer override, but don't have
189 HPET
191 acpi.debug_layer= [HW,ACPI]
192 Format: <int>
193 Each bit of the <int> indicates an ACPI debug layer,
194 1: enable, 0: disable. It is useful for boot time
195 debugging. After system has booted up, it can be set
196 via /sys/module/acpi/parameters/debug_layer.
197 CONFIG_ACPI_DEBUG must be enabled for this to produce any output.
198 Available bits (add the numbers together) to enable debug output
199 for specific parts of the ACPI subsystem:
200 0x01 utilities 0x02 hardware 0x04 events 0x08 tables
201 0x10 namespace 0x20 parser 0x40 dispatcher
202 0x80 executer 0x100 resources 0x200 acpica debugger
203 0x400 os services 0x800 acpica disassembler.
204 The number can be in decimal or prefixed with 0x in hex.
205 Warning: Many of these options can produce a lot of
206 output and make your system unusable. Be very careful.
208 acpi.debug_level= [HW,ACPI]
209 Format: <int>
210 Each bit of the <int> indicates an ACPI debug level,
211 1: enable, 0: disable. It is useful for boot time
212 debugging. After system has booted up, it can be set
213 via /sys/module/acpi/parameters/debug_level.
214 CONFIG_ACPI_DEBUG must be enabled for this to produce any output.
215 Available bits (add the numbers together) to enable different
216 debug output levels of the ACPI subsystem:
217 0x01 error 0x02 warn 0x04 init 0x08 debug object
218 0x10 info 0x20 init names 0x40 parse 0x80 load
219 0x100 dispatch 0x200 execute 0x400 names 0x800 operation region
220 0x1000 bfield 0x2000 tables 0x4000 values 0x8000 objects
221 0x10000 resources 0x20000 user requests 0x40000 package.
222 The number can be in decimal or prefixed with 0x in hex.
223 Warning: Many of these options can produce a lot of
224 output and make your system unusable. Be very careful.
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.
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)
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.
243 disable_timer_pin_1 [i386,x86-64]
244 Disable PIN 1 of APIC timer
245 Can be useful to work around chipset bugs.
247 ad1848= [HW,OSS]
248 Format: <io>,<irq>,<dma>,<dma2>,<type>
250 advansys= [HW,SCSI]
251 See header of drivers/scsi/advansys.c.
253 advwdt= [HW,WDT] Advantech WDT
254 Format: <iostart>,<iostop>
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.
260 aha152x= [HW,SCSI]
261 See Documentation/scsi/aha152x.txt.
263 aha1542= [HW,SCSI]
264 Format: <portbase>[,<buson>,<busoff>[,<dmaspeed>]]
266 aic7xxx= [HW,SCSI]
267 See Documentation/scsi/aic7xxx.txt.
269 aic79xx= [HW,SCSI]
270 See Documentation/scsi/aic79xx.txt.
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
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>
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.
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.
295 apm= [APM] Advanced Power Management
296 See header of arch/i386/kernel/apm.c.
298 arcrimi= [HW,NET] ARCnet - "RIM I" (entirely mem-mapped) cards
299 Format: <io>,<irq>,<nodeID>
301 ataflop= [HW,M68k]
303 atarimouse= [HW,MOUSE] Atari Mouse
305 atascsi= [HW,SCSI] Atari SCSI
307 atkbd.extra= [HW] Enable extra LEDs and keys on IBM RapidAccess,
308 EzKey and similar keyboards
310 atkbd.reset= [HW] Reset keyboard during initialization
312 atkbd.set= [HW] Select keyboard code set
313 Format: <int> (2 = AT (default), 3 = PS/2)
315 atkbd.scroll= [HW] Enable scroll wheel on MS Office and similar
316 keyboards
318 atkbd.softraw= [HW] Choose between synthetic and real raw mode
319 Format: <bool> (0 = real, 1 = synthetic (default))
321 atkbd.softrepeat= [HW]
322 Use software keyboard repeat
324 autotest [IA64]
326 baycom_epp= [HW,AX25]
327 Format: <io>,<mode>
329 baycom_par= [HW,AX25] BayCom Parallel Port AX.25 Modem
330 Format: <io>,<mode>
331 See header of drivers/net/hamradio/baycom_par.c.
333 baycom_ser_fdx= [HW,AX25]
334 BayCom Serial Port AX.25 Modem (Full Duplex Mode)
335 Format: <io>,<irq>,<mode>[,<baud>]
336 See header of drivers/net/hamradio/baycom_ser_fdx.c.
338 baycom_ser_hdx= [HW,AX25]
339 BayCom Serial Port AX.25 Modem (Half Duplex Mode)
340 Format: <io>,<irq>,<mode>
341 See header of drivers/net/hamradio/baycom_ser_hdx.c.
343 boot_delay= Milliseconds to delay each printk during boot.
344 Values larger than 10 seconds (10000) are changed to
345 no delay (0).
346 Format: integer
348 bttv.card= [HW,V4L] bttv (bt848 + bt878 based grabber cards)
349 bttv.radio= Most important insmod options are available as
350 kernel args too.
351 bttv.pll= See Documentation/video4linux/bttv/Insmod-options
352 bttv.tuner= and Documentation/video4linux/bttv/CARDLIST
354 BusLogic= [HW,SCSI]
355 See drivers/scsi/BusLogic.c, comment before function
356 BusLogic_ParseDriverOptions().
358 c101= [NET] Moxa C101 synchronous serial card
360 cachesize= [BUGS=X86-32] Override level 2 CPU cache size detection.
361 Sometimes CPU hardware bugs make them report the cache
362 size incorrectly. The kernel will attempt work arounds
363 to fix known problems, but for some CPUs it is not
364 possible to determine what the correct size should be.
365 This option provides an override for these situations.
367 capability.disable=
368 [SECURITY] Disable capabilities. This would normally
369 be used only if an alternative security model is to be
370 configured. Potentially dangerous and should only be
371 used if you are entirely sure of the consequences.
373 ccw_timeout_log [S390]
374 See Documentation/s390/CommonIO for details.
376 checkreqprot [SELINUX] Set initial checkreqprot flag value.
377 Format: { "0" | "1" }
378 See security/selinux/Kconfig help text.
379 0 -- check protection applied by kernel (includes
380 any implied execute protection).
381 1 -- check protection requested by application.
382 Default value is set via a kernel config option.
383 Value can be changed at runtime via
384 /selinux/checkreqprot.
386 cio_ignore= [S390]
387 See Documentation/s390/CommonIO for details.
389 cio_msg= [S390]
390 See Documentation/s390/CommonIO for details.
392 clock= [BUGS=X86-32, HW] gettimeofday clocksource override.
393 [Deprecated]
394 Forces specified clocksource (if available) to be used
395 when calculating gettimeofday(). If specified
396 clocksource is not available, it defaults to PIT.
397 Format: { pit | tsc | cyclone | pmtmr }
399 clocksource= [GENERIC_TIME] Override the default clocksource
400 Format: <string>
401 Override the default clocksource and use the clocksource
402 with the name specified.
403 Some clocksource names to choose from, depending on
404 the platform:
405 [all] jiffies (this is the base, fallback clocksource)
406 [ACPI] acpi_pm
407 [ARM] imx_timer1,OSTS,netx_timer,mpu_timer2,
408 pxa_timer,timer3,32k_counter,timer0_1
409 [AVR32] avr32
410 [X86-32] pit,hpet,tsc,vmi-timer;
411 scx200_hrt on Geode; cyclone on IBM x440
412 [MIPS] MIPS
413 [PARISC] cr16
414 [S390] tod
415 [SH] SuperH
416 [SPARC64] tick
417 [X86-64] hpet,tsc
419 clearcpuid=BITNUM [X86]
420 Disable CPUID feature X for the kernel. See
421 include/asm-x86/cpufeature.h for the valid bit numbers.
422 Note the Linux specific bits are not necessarily
423 stable over kernel options, but the vendor specific
424 ones should be.
425 Also note that user programs calling CPUID directly
426 or using the feature without checking anything
427 will still see it. This just prevents it from
428 being used by the kernel or shown in /proc/cpuinfo.
429 Also note the kernel might malfunction if you disable
430 some critical bits.
432 code_bytes [IA32/X86_64] How many bytes of object code to print
433 in an oops report.
434 Range: 0 - 8192
435 Default: 64
437 disable_8254_timer
438 enable_8254_timer
439 [IA32/X86_64] Disable/Enable interrupt 0 timer routing
440 over the 8254 in addition to over the IO-APIC. The
441 kernel tries to set a sensible default.
443 hpet= [X86-32,HPET] option to control HPET usage
444 Format: { enable (default) | disable | force }
445 disable: disable HPET and use PIT instead
446 force: allow force enabled of undocumented chips (ICH4,
447 VIA, nVidia)
449 com20020= [HW,NET] ARCnet - COM20020 chipset
450 Format:
451 <io>[,<irq>[,<nodeID>[,<backplane>[,<ckp>[,<timeout>]]]]]
453 com90io= [HW,NET] ARCnet - COM90xx chipset (IO-mapped buffers)
454 Format: <io>[,<irq>]
456 com90xx= [HW,NET]
457 ARCnet - COM90xx chipset (memory-mapped buffers)
458 Format: <io>[,<irq>[,<memstart>]]
460 condev= [HW,S390] console device
461 conmode=
463 console= [KNL] Output console device and options.
465 tty<n> Use the virtual console device <n>.
467 ttyS<n>[,options]
468 ttyUSB0[,options]
469 Use the specified serial port. The options are of
470 the form "bbbbpnf", where "bbbb" is the baud rate,
471 "p" is parity ("n", "o", or "e"), "n" is number of
472 bits, and "f" is flow control ("r" for RTS or
473 omit it). Default is "9600n8".
475 See Documentation/serial-console.txt for more
476 information. See
477 Documentation/networking/netconsole.txt for an
478 alternative.
480 uart[8250],io,<addr>[,options]
481 uart[8250],mmio,<addr>[,options]
482 Start an early, polled-mode console on the 8250/16550
483 UART at the specified I/O port or MMIO address,
484 switching to the matching ttyS device later. The
485 options are the same as for ttyS, above.
487 earlycon= [KNL] Output early console device and options.
488 uart[8250],io,<addr>[,options]
489 uart[8250],mmio,<addr>[,options]
490 Start an early, polled-mode console on the 8250/16550
491 UART at the specified I/O port or MMIO address.
492 The options are the same as for ttyS, above.
494 no_console_suspend
495 [HW] Never suspend the console
496 Disable suspending of consoles during suspend and
497 hibernate operations. Once disabled, debugging
498 messages can reach various consoles while the rest
499 of the system is being put to sleep (ie, while
500 debugging driver suspend/resume hooks). This may
501 not work reliably with all consoles, but is known
502 to work with serial and VGA consoles.
504 cpcihp_generic= [HW,PCI] Generic port I/O CompactPCI driver
505 Format:
506 <first_slot>,<last_slot>,<port>,<enum_bit>[,<debug>]
508 crashkernel=nn[KMG]@ss[KMG]
509 [KNL] Reserve a chunk of physical memory to
510 hold a kernel to switch to with kexec on panic.
512 crashkernel=range1:size1[,range2:size2,...][@offset]
513 [KNL] Same as above, but depends on the memory
514 in the running system. The syntax of range is
515 start-[end] where start and end are both
516 a memory unit (amount[KMG]). See also
517 Documentation/kdump/kdump.txt for a example.
519 cs4232= [HW,OSS]
520 Format: <io>,<irq>,<dma>,<dma2>,<mpuio>,<mpuirq>
522 cs89x0_dma= [HW,NET]
523 Format: <dma>
525 cs89x0_media= [HW,NET]
526 Format: { rj45 | aui | bnc }
528 dasd= [HW,NET]
529 See header of drivers/s390/block/dasd_devmap.c.
531 db9.dev[2|3]= [HW,JOY] Multisystem joystick support via parallel port
532 (one device per port)
533 Format: <port#>,<type>
534 See also Documentation/input/joystick-parport.txt
536 debug [KNL] Enable kernel debugging (events log level).
538 debug_locks_verbose=
539 [KNL] verbose self-tests
540 Format=<0|1>
541 Print debugging info while doing the locking API
542 self-tests.
543 We default to 0 (no extra messages), setting it to
544 1 will print _a lot_ more information - normally
545 only useful to kernel developers.
547 decnet= [HW,NET]
548 Format: <area>[,<node>]
549 See also Documentation/networking/decnet.txt.
551 vt.default_blu= [VT]
552 Format: <blue0>,<blue1>,<blue2>,...,<blue15>
553 Change the default blue palette of the console.
554 This is a 16-member array composed of values
555 ranging from 0-255.
557 vt.default_grn= [VT]
558 Format: <green0>,<green1>,<green2>,...,<green15>
559 Change the default green palette of the console.
560 This is a 16-member array composed of values
561 ranging from 0-255.
563 vt.default_red= [VT]
564 Format: <red0>,<red1>,<red2>,...,<red15>
565 Change the default red palette of the console.
566 This is a 16-member array composed of values
567 ranging from 0-255.
569 vt.default_utf8=
570 [VT]
571 Format=<0|1>
572 Set system-wide default UTF-8 mode for all tty's.
573 Default is 1, i.e. UTF-8 mode is enabled for all
574 newly opened terminals.
576 dhash_entries= [KNL]
577 Set number of hash buckets for dentry cache.
579 digi= [HW,SERIAL]
580 IO parameters + enable/disable command.
582 digiepca= [HW,SERIAL]
583 See drivers/char/README.epca and
584 Documentation/digiepca.txt.
586 disable_mtrr_trim [X86, Intel and AMD only]
587 By default the kernel will trim any uncacheable
588 memory out of your available memory pool based on
589 MTRR settings. This parameter disables that behavior,
590 possibly causing your machine to run very slowly.
592 dmasound= [HW,OSS] Sound subsystem buffers
594 dscc4.setup= [NET]
596 dtc3181e= [HW,SCSI]
598 earlyprintk= [X86-32,X86-64,SH,BLACKFIN]
599 earlyprintk=vga
600 earlyprintk=serial[,ttySn[,baudrate]]
602 Append ",keep" to not disable it when the real console
603 takes over.
605 Only vga or serial at a time, not both.
607 Currently only ttyS0 and ttyS1 are supported.
609 Interaction with the standard serial driver is not
610 very good.
612 The VGA output is eventually overwritten by the real
613 console.
615 eata= [HW,SCSI]
617 edd= [EDD]
618 Format: {"of[f]" | "sk[ipmbr]"}
619 See comment in arch/i386/boot/edd.S
621 eisa_irq_edge= [PARISC,HW]
622 See header of drivers/parisc/eisa.c.
624 elanfreq= [X86-32]
625 See comment before function elanfreq_setup() in
626 arch/i386/kernel/cpu/cpufreq/elanfreq.c.
628 elevator= [IOSCHED]
629 Format: {"anticipatory" | "cfq" | "deadline" | "noop"}
630 See Documentation/block/as-iosched.txt and
631 Documentation/block/deadline-iosched.txt for details.
633 elfcorehdr= [X86-32, X86_64]
634 Specifies physical address of start of kernel core
635 image elf header. Generally kexec loader will
636 pass this option to capture kernel.
637 See Documentation/kdump/kdump.txt for details.
639 enforcing [SELINUX] Set initial enforcing status.
640 Format: {"0" | "1"}
641 See security/selinux/Kconfig help text.
642 0 -- permissive (log only, no denials).
643 1 -- enforcing (deny and log).
644 Default value is 0.
645 Value can be changed at runtime via /selinux/enforce.
647 es1371= [HW,OSS]
648 Format: <spdif>,[<nomix>,[<amplifier>]]
649 See also header of sound/oss/es1371.c.
651 ether= [HW,NET] Ethernet cards parameters
652 This option is obsoleted by the "netdev=" option, which
653 has equivalent usage. See its documentation for details.
655 eurwdt= [HW,WDT] Eurotech CPU-1220/1410 onboard watchdog.
656 Format: <io>[,<irq>]
658 failslab=
659 fail_page_alloc=
660 fail_make_request=[KNL]
661 General fault injection mechanism.
662 Format: <interval>,<probability>,<space>,<times>
663 See also /Documentation/fault-injection/.
665 fd_mcs= [HW,SCSI]
666 See header of drivers/scsi/fd_mcs.c.
668 fdomain= [HW,SCSI]
669 See header of drivers/scsi/fdomain.c.
671 floppy= [HW]
672 See Documentation/floppy.txt.
674 gamecon.map[2|3]=
675 [HW,JOY] Multisystem joystick and NES/SNES/PSX pad
676 support via parallel port (up to 5 devices per port)
677 Format: <port#>,<pad1>,<pad2>,<pad3>,<pad4>,<pad5>
678 See also Documentation/input/joystick-parport.txt
680 gamma= [HW,DRM]
682 gart_fix_e820= [X86_64] disable the fix e820 for K8 GART
683 Format: off | on
684 default: on
686 gdth= [HW,SCSI]
687 See header of drivers/scsi/gdth.c.
689 gpt [EFI] Forces disk with valid GPT signature but
690 invalid Protective MBR to be treated as GPT.
692 gvp11= [HW,SCSI]
694 hashdist= [KNL,NUMA] Large hashes allocated during boot
695 are distributed across NUMA nodes. Defaults on
696 for IA-64, off otherwise.
697 Format: 0 | 1 (for off | on)
699 hcl= [IA-64] SGI's Hardware Graph compatibility layer
701 hd= [EIDE] (E)IDE hard drive subsystem geometry
702 Format: <cyl>,<head>,<sect>
704 hd?= [HW] (E)IDE subsystem
705 hd?lun= See Documentation/ide.txt.
707 highmem=nn[KMG] [KNL,BOOT] forces the highmem zone to have an exact
708 size of <nn>. This works even on boxes that have no
709 highmem otherwise. This also works to reduce highmem
710 size on bigger boxes.
712 highres= [KNL] Enable/disable high resolution timer mode.
713 Valid parameters: "on", "off"
714 Default: "on"
716 hisax= [HW,ISDN]
717 See Documentation/isdn/README.HiSax.
719 hugepages= [HW,X86-32,IA-64] Maximal number of HugeTLB pages.
720 hugepagesz= [HW,IA-64,PPC] The size of the HugeTLB pages.
722 i8042.direct [HW] Put keyboard port into non-translated mode
723 i8042.dumbkbd [HW] Pretend that controller can only read data from
724 keyboard and cannot control its state
725 (Don't attempt to blink the leds)
726 i8042.noaux [HW] Don't check for auxiliary (== mouse) port
727 i8042.nokbd [HW] Don't check/create keyboard port
728 i8042.nomux [HW] Don't check presence of an active multiplexing
729 controller
730 i8042.nopnp [HW] Don't use ACPIPnP / PnPBIOS to discover KBD/AUX
731 controllers
732 i8042.panicblink=
733 [HW] Frequency with which keyboard LEDs should blink
734 when kernel panics (default is 0.5 sec)
735 i8042.reset [HW] Reset the controller during init and cleanup
736 i8042.unlock [HW] Unlock (ignore) the keylock
738 i810= [HW,DRM]
740 i8k.ignore_dmi [HW] Continue probing hardware even if DMI data
741 indicates that the driver is running on unsupported
742 hardware.
743 i8k.force [HW] Activate i8k driver even if SMM BIOS signature
744 does not match list of supported models.
745 i8k.power_status
746 [HW] Report power status in /proc/i8k
747 (disabled by default)
748 i8k.restricted [HW] Allow controlling fans only if SYS_ADMIN
749 capability is set.
751 ibmmcascsi= [HW,MCA,SCSI] IBM MicroChannel SCSI adapter
752 See Documentation/mca.txt.
754 icn= [HW,ISDN]
755 Format: <io>[,<membase>[,<icn_id>[,<icn_id2>]]]
757 ide= [HW] (E)IDE subsystem
758 Format: ide=nodma or ide=doubler or ide=reverse
759 See Documentation/ide.txt.
761 ide?= [HW] (E)IDE subsystem
762 Format: ide?=noprobe or chipset specific parameters.
763 See Documentation/ide.txt.
765 idebus= [HW] (E)IDE subsystem - VLB/PCI bus speed
766 See Documentation/ide.txt.
768 idle= [X86]
769 Format: idle=poll or idle=mwait
770 Poll forces a polling idle loop that can slightly improves the performance
771 of waking up a idle CPU, but will use a lot of power and make the system
772 run hot. Not recommended.
773 idle=mwait. On systems which support MONITOR/MWAIT but the kernel chose
774 to not use it because it doesn't save as much power as a normal idle
775 loop use the MONITOR/MWAIT idle loop anyways. Performance should be the same
776 as idle=poll.
778 ignore_loglevel [KNL]
779 Ignore loglevel setting - this will print /all/
780 kernel messages to the console. Useful for debugging.
782 ihash_entries= [KNL]
783 Set number of hash buckets for inode cache.
785 in2000= [HW,SCSI]
786 See header of drivers/scsi/in2000.c.
788 init= [KNL]
789 Format: <full_path>
790 Run specified binary instead of /sbin/init as init
791 process.
793 initcall_debug [KNL] Trace initcalls as they are executed. Useful
794 for working out where the kernel is dying during
795 startup.
797 initrd= [BOOT] Specify the location of the initial ramdisk
799 inport.irq= [HW] Inport (ATI XL and Microsoft) busmouse driver
800 Format: <irq>
802 inttest= [IA64]
804 intel_iommu= [DMAR] Intel IOMMU driver (DMAR) option
805 off
806 Disable intel iommu driver.
807 igfx_off [Default Off]
808 By default, gfx is mapped as normal device. If a gfx
809 device has a dedicated DMAR unit, the DMAR unit is
810 bypassed by not enabling DMAR with this option. In
811 this case, gfx device will use physical address for
812 DMA.
813 forcedac [x86_64]
814 With this option iommu will not optimize to look
815 for io virtual address below 32 bit forcing dual
816 address cycle on pci bus for cards supporting greater
817 than 32 bit addressing. The default is to look
818 for translation below 32 bit and if not available
819 then look in the higher range.
821 io_delay= [X86-32,X86-64] I/O delay method
822 0x80
823 Standard port 0x80 based delay
824 0xed
825 Alternate port 0xed based delay (needed on some systems)
826 udelay
827 Simple two microseconds delay
828 none
829 No delay
831 io7= [HW] IO7 for Marvel based alpha systems
832 See comment before marvel_specify_io7 in
833 arch/alpha/kernel/core_marvel.c.
835 ip= [IP_PNP]
836 See Documentation/nfsroot.txt.
838 ip2= [HW] Set IO/IRQ pairs for up to 4 IntelliPort boards
839 See comment before ip2_setup() in
840 drivers/char/ip2/ip2base.c.
842 ips= [HW,SCSI] Adaptec / IBM ServeRAID controller
843 See header of drivers/scsi/ips.c.
845 ports= [IP_VS_FTP] IPVS ftp helper module
846 Default is 21.
847 Up to 8 (IP_VS_APP_MAX_PORTS) ports
848 may be specified.
849 Format: <port>,<port>....
851 irqfixup [HW]
852 When an interrupt is not handled search all handlers
853 for it. Intended to get systems with badly broken
854 firmware running.
856 irqpoll [HW]
857 When an interrupt is not handled search all handlers
858 for it. Also check all handlers each timer
859 interrupt. Intended to get systems with badly broken
860 firmware running.
862 isapnp= [ISAPNP]
863 Format: <RDP>,<reset>,<pci_scan>,<verbosity>
865 isolcpus= [KNL,SMP] Isolate CPUs from the general scheduler.
866 Format:
867 <cpu number>,...,<cpu number>
868 or
869 <cpu number>-<cpu number> (must be a positive range in ascending order)
870 or a mixture
871 <cpu number>,...,<cpu number>-<cpu number>
872 This option can be used to specify one or more CPUs
873 to isolate from the general SMP balancing and scheduling
874 algorithms. The only way to move a process onto or off
875 an "isolated" CPU is via the CPU affinity syscalls.
876 <cpu number> begins at 0 and the maximum value is
877 "number of CPUs in system - 1".
879 This option is the preferred way to isolate CPUs. The
880 alternative -- manually setting the CPU mask of all
881 tasks in the system -- can cause problems and
882 suboptimal load balancer performance.
884 iucv= [HW,NET]
886 js= [HW,JOY] Analog joystick
887 See Documentation/input/joystick.txt.
889 kernelcore=nn[KMG] [KNL,X86-32,IA-64,PPC,X86-64] This parameter
890 specifies the amount of memory usable by the kernel
891 for non-movable allocations. The requested amount is
892 spread evenly throughout all nodes in the system. The
893 remaining memory in each node is used for Movable
894 pages. In the event, a node is too small to have both
895 kernelcore and Movable pages, kernelcore pages will
896 take priority and other nodes will have a larger number
897 of kernelcore pages. The Movable zone is used for the
898 allocation of pages that may be reclaimed or moved
899 by the page migration subsystem. This means that
900 HugeTLB pages may not be allocated from this zone.
901 Note that allocations like PTEs-from-HighMem still
902 use the HighMem zone if it exists, and the Normal
903 zone if it does not.
905 movablecore=nn[KMG] [KNL,X86-32,IA-64,PPC,X86-64] This parameter
906 is similar to kernelcore except it specifies the
907 amount of memory used for migratable allocations.
908 If both kernelcore and movablecore is specified,
909 then kernelcore will be at *least* the specified
910 value but may be more. If movablecore on its own
911 is specified, the administrator must be careful
912 that the amount of memory usable for all allocations
913 is not too small.
915 keepinitrd [HW,ARM]
917 kstack=N [X86-32,X86-64] Print N words from the kernel stack
918 in oops dumps.
920 l2cr= [PPC]
922 lapic [X86-32,APIC] Enable the local APIC even if BIOS
923 disabled it.
925 lapic_timer_c2_ok [X86-32,x86-64,APIC] trust the local apic timer in
926 C2 power state.
928 libata.dma= [LIBATA] DMA control
929 libata.dma=0 Disable all PATA and SATA DMA
930 libata.dma=1 PATA and SATA Disk DMA only
931 libata.dma=2 ATAPI (CDROM) DMA only
932 libata.dma=4 Compact Flash DMA only
933 Combinations also work, so libata.dma=3 enables DMA
934 for disks and CDROMs, but not CFs.
936 libata.noacpi [LIBATA] Disables use of ACPI in libata suspend/resume
937 when set.
938 Format: <int>
940 load_ramdisk= [RAM] List of ramdisks to load from floppy
941 See Documentation/ramdisk.txt.
943 lockd.nlm_grace_period=P [NFS] Assign grace period.
944 Format: <integer>
946 lockd.nlm_tcpport=N [NFS] Assign TCP port.
947 Format: <integer>
949 lockd.nlm_timeout=T [NFS] Assign timeout value.
950 Format: <integer>
952 lockd.nlm_udpport=M [NFS] Assign UDP port.
953 Format: <integer>
955 logibm.irq= [HW,MOUSE] Logitech Bus Mouse Driver
956 Format: <irq>
958 loglevel= All Kernel Messages with a loglevel smaller than the
959 console loglevel will be printed to the console. It can
960 also be changed with klogd or other programs. The
961 loglevels are defined as follows:
963 0 (KERN_EMERG) system is unusable
964 1 (KERN_ALERT) action must be taken immediately
965 2 (KERN_CRIT) critical conditions
966 3 (KERN_ERR) error conditions
967 4 (KERN_WARNING) warning conditions
968 5 (KERN_NOTICE) normal but significant condition
969 6 (KERN_INFO) informational
970 7 (KERN_DEBUG) debug-level messages
972 log_buf_len=n Sets the size of the printk ring buffer, in bytes.
973 Format: { n | nk | nM }
974 n must be a power of two. The default size
975 is set in the kernel config file.
977 logo.nologo [FB] Disables display of the built-in Linux logo.
978 This may be used to provide more screen space for
979 kernel log messages and is useful when debugging
980 kernel boot problems.
982 lp=0 [LP] Specify parallel ports to use, e.g,
983 lp=port[,port...] lp=none,parport0 (lp0 not configured, lp1 uses
984 lp=reset first parallel port). 'lp=0' disables the
985 lp=auto printer driver. 'lp=reset' (which can be
986 specified in addition to the ports) causes
987 attached printers to be reset. Using
988 lp=port1,port2,... specifies the parallel ports
989 to associate lp devices with, starting with
990 lp0. A port specification may be 'none' to skip
991 that lp device, or a parport name such as
992 'parport0'. Specifying 'lp=auto' instead of a
993 port specification list means that device IDs
994 from each port should be examined, to see if
995 an IEEE 1284-compliant printer is attached; if
996 so, the driver will manage that printer.
997 See also header of drivers/char/lp.c.
999 lpj=n [KNL]
1000 Sets loops_per_jiffy to given constant, thus avoiding
1001 time-consuming boot-time autodetection (up to 250 ms per
1002 CPU). 0 enables autodetection (default). To determine
1003 the correct value for your kernel, boot with normal
1004 autodetection and see what value is printed. Note that
1005 on SMP systems the preset will be applied to all CPUs,
1006 which is likely to cause problems if your CPUs need
1007 significantly divergent settings. An incorrect value
1008 will cause delays in the kernel to be wrong, leading to
1009 unpredictable I/O errors and other breakage. Although
1010 unlikely, in the extreme case this might damage your
1011 hardware.
1013 ltpc= [NET]
1014 Format: <io>,<irq>,<dma>
1016 mac5380= [HW,SCSI] Format:
1017 <can_queue>,<cmd_per_lun>,<sg_tablesize>,<hostid>,<use_tags>
1019 mac53c9x= [HW,SCSI] Format:
1020 <num_esps>,<disconnect>,<nosync>,<can_queue>,<cmd_per_lun>,<sg_tablesize>,<hostid>,<use_tags>
1022 machvec= [IA64] Force the use of a particular machine-vector
1023 (machvec) in a generic kernel.
1024 Example: machvec=hpzx1_swiotlb
1026 max_loop= [LOOP] Maximum number of loopback devices that can
1027 be mounted
1028 Format: <1-256>
1030 maxcpus= [SMP] Maximum number of processors that an SMP kernel
1031 should make use of. maxcpus=n : n >= 0 limits the
1032 kernel to using 'n' processors. n=0 is a special case,
1033 it is equivalent to "nosmp", which also disables
1034 the IO APIC.
1036 max_addr=[KMG] [KNL,BOOT,ia64] All physical memory greater than or
1037 equal to this physical address is ignored.
1039 max_luns= [SCSI] Maximum number of LUNs to probe.
1040 Should be between 1 and 2^32-1.
1042 max_report_luns=
1043 [SCSI] Maximum number of LUNs received.
1044 Should be between 1 and 16384.
1046 mca-pentium [BUGS=X86-32]
1048 mcatest= [IA-64]
1050 mce [X86-32] Machine Check Exception
1052 mce=option [X86-64] See Documentation/x86_64/boot-options.txt
1054 md= [HW] RAID subsystems devices and level
1055 See Documentation/md.txt.
1057 mdacon= [MDA]
1058 Format: <first>,<last>
1059 Specifies range of consoles to be captured by the MDA.
1061 mem=nn[KMG] [KNL,BOOT] Force usage of a specific amount of memory
1062 Amount of memory to be used when the kernel is not able
1063 to see the whole system memory or for test.
1064 [X86-32] Use together with memmap= to avoid physical
1065 address space collisions. Without memmap= PCI devices
1066 could be placed at addresses belonging to unused RAM.
1068 mem=nopentium [BUGS=X86-32] Disable usage of 4MB pages for kernel
1069 memory.
1071 memmap=exactmap [KNL,X86-32,X86_64] Enable setting of an exact
1072 E820 memory map, as specified by the user.
1073 Such memmap=exactmap lines can be constructed based on
1074 BIOS output or other requirements. See the memmap=nn@ss
1075 option description.
1077 memmap=nn[KMG]@ss[KMG]
1078 [KNL] Force usage of a specific region of memory
1079 Region of memory to be used, from ss to ss+nn.
1081 memmap=nn[KMG]#ss[KMG]
1082 [KNL,ACPI] Mark specific memory as ACPI data.
1083 Region of memory to be used, from ss to ss+nn.
1085 memmap=nn[KMG]$ss[KMG]
1086 [KNL,ACPI] Mark specific memory as reserved.
1087 Region of memory to be used, from ss to ss+nn.
1089 meye.*= [HW] Set MotionEye Camera parameters
1090 See Documentation/video4linux/meye.txt.
1092 mfgpt_irq= [IA-32] Specify the IRQ to use for the
1093 Multi-Function General Purpose Timers on AMD Geode
1094 platforms.
1096 mfgptfix [X86-32] Fix MFGPT timers on AMD Geode platforms when
1097 the BIOS has incorrectly applied a workaround. TinyBIOS
1098 version 0.98 is known to be affected, 0.99 fixes the
1099 problem by letting the user disable the workaround.
1101 mga= [HW,DRM]
1103 mousedev.tap_time=
1104 [MOUSE] Maximum time between finger touching and
1105 leaving touchpad surface for touch to be considered
1106 a tap and be reported as a left button click (for
1107 touchpads working in absolute mode only).
1108 Format: <msecs>
1109 mousedev.xres= [MOUSE] Horizontal screen resolution, used for devices
1110 reporting absolute coordinates, such as tablets
1111 mousedev.yres= [MOUSE] Vertical screen resolution, used for devices
1112 reporting absolute coordinates, such as tablets
1114 mpu401= [HW,OSS]
1115 Format: <io>,<irq>
1117 MTD_Partition= [MTD]
1118 Format: <name>,<region-number>,<size>,<offset>
1120 MTD_Region= [MTD] Format:
1121 <name>,<region-number>[,<base>,<size>,<buswidth>,<altbuswidth>]
1123 mtdparts= [MTD]
1124 See drivers/mtd/cmdlinepart.c.
1126 mtouchusb.raw_coordinates=
1127 [HW] Make the MicroTouch USB driver use raw coordinates
1128 ('y', default) or cooked coordinates ('n')
1130 n2= [NET] SDL Inc. RISCom/N2 synchronous serial card
1132 NCR_D700= [HW,SCSI]
1133 See header of drivers/scsi/NCR_D700.c.
1135 ncr5380= [HW,SCSI]
1137 ncr53c400= [HW,SCSI]
1139 ncr53c400a= [HW,SCSI]
1141 ncr53c406a= [HW,SCSI]
1143 ncr53c8xx= [HW,SCSI]
1145 netdev= [NET] Network devices parameters
1146 Format: <irq>,<io>,<mem_start>,<mem_end>,<name>
1147 Note that mem_start is often overloaded to mean
1148 something different and driver-specific.
1149 This usage is only documented in each driver source
1150 file if at all.
1152 nfsaddrs= [NFS]
1153 See Documentation/nfsroot.txt.
1155 nfsroot= [NFS] nfs root filesystem for disk-less boxes.
1156 See Documentation/nfsroot.txt.
1158 nfs.callback_tcpport=
1159 [NFS] set the TCP port on which the NFSv4 callback
1160 channel should listen.
1162 nfs.idmap_cache_timeout=
1163 [NFS] set the maximum lifetime for idmapper cache
1164 entries.
1166 nfs.enable_ino64=
1167 [NFS] enable 64-bit inode numbers.
1168 If zero, the NFS client will fake up a 32-bit inode
1169 number for the readdir() and stat() syscalls instead
1170 of returning the full 64-bit number.
1171 The default is to return 64-bit inode numbers.
1173 nmi_debug= [KNL,AVR32] Specify one or more actions to take
1174 when a NMI is triggered.
1175 Format: [state][,regs][,debounce][,die]
1177 nmi_watchdog= [KNL,BUGS=X86-32] Debugging features for SMP kernels
1179 no387 [BUGS=X86-32] Tells the kernel to use the 387 maths
1180 emulation library even if a 387 maths coprocessor
1181 is present.
1183 noaliencache [MM, NUMA, SLAB] Disables the allocation of alien
1184 caches in the slab allocator. Saves per-node memory,
1185 but will impact performance.
1187 noalign [KNL,ARM]
1189 noapic [SMP,APIC] Tells the kernel to not make use of any
1190 IOAPICs that may be present in the system.
1192 nobats [PPC] Do not use BATs for mapping kernel lowmem
1193 on "Classic" PPC cores.
1195 nocache [ARM]
1197 nodelayacct [KNL] Disable per-task delay accounting
1199 nodisconnect [HW,SCSI,M68K] Disables SCSI disconnects.
1201 noefi [X86-32,X86-64] Disable EFI runtime services support.
1203 noexec [IA-64]
1205 noexec [X86-32,X86-64]
1206 noexec=on: enable non-executable mappings (default)
1207 noexec=off: disable nn-executable mappings
1209 nofxsr [BUGS=X86-32] Disables x86 floating point extended
1210 register save and restore. The kernel will only save
1211 legacy floating-point registers on task switch.
1213 noclflush [BUGS=X86] Don't use the CLFLUSH instruction
1215 nohlt [BUGS=ARM]
1217 no-hlt [BUGS=X86-32] Tells the kernel that the hlt
1218 instruction doesn't work correctly and not to
1219 use it.
1221 nohalt [IA-64] Tells the kernel not to use the power saving
1222 function PAL_HALT_LIGHT when idle. This increases
1223 power-consumption. On the positive side, it reduces
1224 interrupt wake-up latency, which may improve performance
1225 in certain environments such as networked servers or
1226 real-time systems.
1228 nohz= [KNL] Boottime enable/disable dynamic ticks
1229 Valid arguments: on, off
1230 Default: on
1232 noirqbalance [X86-32,SMP,KNL] Disable kernel irq balancing
1234 noirqdebug [X86-32] Disables the code which attempts to detect and
1235 disable unhandled interrupt sources.
1237 no_timer_check [X86-32,X86_64,APIC] Disables the code which tests for
1238 broken timer IRQ sources.
1240 noisapnp [ISAPNP] Disables ISA PnP code.
1242 noinitrd [RAM] Tells the kernel not to load any configured
1243 initial RAM disk.
1245 nointroute [IA-64]
1247 nojitter [IA64] Disables jitter checking for ITC timers.
1249 nolapic [X86-32,APIC] Do not enable or use the local APIC.
1251 nolapic_timer [X86-32,APIC] Do not use the local APIC timer.
1253 noltlbs [PPC] Do not use large page/tlb entries for kernel
1254 lowmem mapping on PPC40x.
1256 nomca [IA-64] Disable machine check abort handling
1258 nomce [X86-32] Machine Check Exception
1260 nomfgpt [X86-32] Disable Multi-Function General Purpose
1261 Timer usage (for AMD Geode machines).
1263 noreplace-paravirt [X86-32,PV_OPS] Don't patch paravirt_ops
1265 noreplace-smp [X86-32,SMP] Don't replace SMP instructions
1266 with UP alternatives
1268 noresidual [PPC] Don't use residual data on PReP machines.
1270 noresume [SWSUSP] Disables resume and restores original swap
1271 space.
1273 no-scroll [VGA] Disables scrollback.
1274 This is required for the Braillex ib80-piezo Braille
1275 reader made by F.H. Papenmeier (Germany).
1277 nosbagart [IA-64]
1279 nosep [BUGS=X86-32] Disables x86 SYSENTER/SYSEXIT support.
1281 nosmp [SMP] Tells an SMP kernel to act as a UP kernel,
1282 and disable the IO APIC. legacy for "maxcpus=0".
1284 nosoftlockup [KNL] Disable the soft-lockup detector.
1286 nosync [HW,M68K] Disables sync negotiation for all devices.
1288 notsc [BUGS=X86-32] Disable Time Stamp Counter
1290 nousb [USB] Disable the USB subsystem
1292 nowb [ARM]
1294 numa_zonelist_order= [KNL, BOOT] Select zonelist order for NUMA.
1295 one of ['zone', 'node', 'default'] can be specified
1296 This can be set from sysctl after boot.
1297 See Documentation/sysctl/vm.txt for details.
1299 nr_uarts= [SERIAL] maximum number of UARTs to be registered.
1301 opl3= [HW,OSS]
1302 Format: <io>
1304 oprofile.timer= [HW]
1305 Use timer interrupt instead of performance counters
1307 osst= [HW,SCSI] SCSI Tape Driver
1308 Format: <buffer_size>,<write_threshold>
1309 See also Documentation/scsi/st.txt.
1311 panic= [KNL] Kernel behaviour on panic
1312 Format: <timeout>
1314 parkbd.port= [HW] Parallel port number the keyboard adapter is
1315 connected to, default is 0.
1316 Format: <parport#>
1317 parkbd.mode= [HW] Parallel port keyboard adapter mode of operation,
1318 0 for XT, 1 for AT (default is AT).
1319 Format: <mode>
1321 parport= [HW,PPT] Specify parallel ports. 0 disables.
1322 Format: { 0 | auto | 0xBBB[,IRQ[,DMA]] }
1323 Use 'auto' to force the driver to use any
1324 IRQ/DMA settings detected (the default is to
1325 ignore detected IRQ/DMA settings because of
1326 possible conflicts). You can specify the base
1327 address, IRQ, and DMA settings; IRQ and DMA
1328 should be numbers, or 'auto' (for using detected
1329 settings on that particular port), or 'nofifo'
1330 (to avoid using a FIFO even if it is detected).
1331 Parallel ports are assigned in the order they
1332 are specified on the command line, starting
1333 with parport0.
1335 parport_init_mode= [HW,PPT]
1336 Configure VIA parallel port to operate in
1337 a specific mode. This is necessary on Pegasos
1338 computer where firmware has no options for setting
1339 up parallel port mode and sets it to spp.
1340 Currently this function knows 686a and 8231 chips.
1341 Format: [spp|ps2|epp|ecp|ecpepp]
1343 pas2= [HW,OSS] Format:
1344 <io>,<irq>,<dma>,<dma16>,<sb_io>,<sb_irq>,<sb_dma>,<sb_dma16>
1346 pas16= [HW,SCSI]
1347 See header of drivers/scsi/pas16.c.
1349 pause_on_oops=
1350 Halt all CPUs after the first oops has been printed for
1351 the specified number of seconds. This is to be used if
1352 your oopses keep scrolling off the screen.
1354 pcbit= [HW,ISDN]
1356 pcd. [PARIDE]
1357 See header of drivers/block/paride/pcd.c.
1358 See also Documentation/paride.txt.
1360 pci=option[,option...] [PCI] various PCI subsystem options:
1361 off [X86-32] don't probe for the PCI bus
1362 bios [X86-32] force use of PCI BIOS, don't access
1363 the hardware directly. Use this if your machine
1364 has a non-standard PCI host bridge.
1365 nobios [X86-32] disallow use of PCI BIOS, only direct
1366 hardware access methods are allowed. Use this
1367 if you experience crashes upon bootup and you
1368 suspect they are caused by the BIOS.
1369 conf1 [X86-32] Force use of PCI Configuration
1370 Mechanism 1.
1371 conf2 [X86-32] Force use of PCI Configuration
1372 Mechanism 2.
1373 noaer [PCIE] If the PCIEAER kernel config parameter is
1374 enabled, this kernel boot option can be used to
1375 disable the use of PCIE advanced error reporting.
1376 nodomains [PCI] Disable support for multiple PCI
1377 root domains (aka PCI segments, in ACPI-speak).
1378 nommconf [X86-32,X86_64] Disable use of MMCONFIG for PCI
1379 Configuration
1380 nomsi [MSI] If the PCI_MSI kernel config parameter is
1381 enabled, this kernel boot option can be used to
1382 disable the use of MSI interrupts system-wide.
1383 nosort [X86-32] Don't sort PCI devices according to
1384 order given by the PCI BIOS. This sorting is
1385 done to get a device order compatible with
1386 older kernels.
1387 biosirq [X86-32] Use PCI BIOS calls to get the interrupt
1388 routing table. These calls are known to be buggy
1389 on several machines and they hang the machine
1390 when used, but on other computers it's the only
1391 way to get the interrupt routing table. Try
1392 this option if the kernel is unable to allocate
1393 IRQs or discover secondary PCI buses on your
1394 motherboard.
1395 rom [X86-32] Assign address space to expansion ROMs.
1396 Use with caution as certain devices share
1397 address decoders between ROMs and other
1398 resources.
1399 irqmask=0xMMMM [X86-32] Set a bit mask of IRQs allowed to be
1400 assigned automatically to PCI devices. You can
1401 make the kernel exclude IRQs of your ISA cards
1402 this way.
1403 pirqaddr=0xAAAAA [X86-32] Specify the physical address
1404 of the PIRQ table (normally generated
1405 by the BIOS) if it is outside the
1406 F0000h-100000h range.
1407 lastbus=N [X86-32] Scan all buses thru bus #N. Can be
1408 useful if the kernel is unable to find your
1409 secondary buses and you want to tell it
1410 explicitly which ones they are.
1411 assign-busses [X86-32] Always assign all PCI bus
1412 numbers ourselves, overriding
1413 whatever the firmware may have done.
1414 usepirqmask [X86-32] Honor the possible IRQ mask stored
1415 in the BIOS $PIR table. This is needed on
1416 some systems with broken BIOSes, notably
1417 some HP Pavilion N5400 and Omnibook XE3
1418 notebooks. This will have no effect if ACPI
1419 IRQ routing is enabled.
1420 noacpi [X86-32] Do not use ACPI for IRQ routing
1421 or for PCI scanning.
1422 use_crs [X86-32] Use _CRS for PCI resource
1423 allocation.
1424 routeirq Do IRQ routing for all PCI devices.
1425 This is normally done in pci_enable_device(),
1426 so this option is a temporary workaround
1427 for broken drivers that don't call it.
1428 firmware [ARM] Do not re-enumerate the bus but instead
1429 just use the configuration from the
1430 bootloader. This is currently used on
1431 IXP2000 systems where the bus has to be
1432 configured a certain way for adjunct CPUs.
1433 noearly [X86] Don't do any early type 1 scanning.
1434 This might help on some broken boards which
1435 machine check when some devices' config space
1436 is read. But various workarounds are disabled
1437 and some IOMMU drivers will not work.
1438 bfsort Sort PCI devices into breadth-first order.
1439 This sorting is done to get a device
1440 order compatible with older (<= 2.4) kernels.
1441 nobfsort Don't sort PCI devices into breadth-first order.
1442 cbiosize=nn[KMG] The fixed amount of bus space which is
1443 reserved for the CardBus bridge's IO window.
1444 The default value is 256 bytes.
1445 cbmemsize=nn[KMG] The fixed amount of bus space which is
1446 reserved for the CardBus bridge's memory
1447 window. The default value is 64 megabytes.
1449 pcmv= [HW,PCMCIA] BadgePAD 4
1451 pd. [PARIDE]
1452 See Documentation/paride.txt.
1454 pdcchassis= [PARISC,HW] Disable/Enable PDC Chassis Status codes at
1455 boot time.
1456 Format: { 0 | 1 }
1457 See arch/parisc/kernel/pdc_chassis.c
1459 pf. [PARIDE]
1460 See Documentation/paride.txt.
1462 pg. [PARIDE]
1463 See Documentation/paride.txt.
1465 pirq= [SMP,APIC] Manual mp-table setup
1466 See Documentation/i386/IO-APIC.txt.
1468 plip= [PPT,NET] Parallel port network link
1469 Format: { parport<nr> | timid | 0 }
1470 See also Documentation/parport.txt.
1472 pnpacpi= [ACPI]
1473 { off }
1475 pnpbios= [ISAPNP]
1476 { on | off | curr | res | no-curr | no-res }
1478 pnp_reserve_irq=
1479 [ISAPNP] Exclude IRQs for the autoconfiguration
1481 pnp_reserve_dma=
1482 [ISAPNP] Exclude DMAs for the autoconfiguration
1484 pnp_reserve_io= [ISAPNP] Exclude I/O ports for the autoconfiguration
1485 Ranges are in pairs (I/O port base and size).
1487 pnp_reserve_mem=
1488 [ISAPNP] Exclude memory regions for the
1489 autoconfiguration.
1490 Ranges are in pairs (memory base and size).
1492 print-fatal-signals=
1493 [KNL] debug: print fatal signals
1494 print-fatal-signals=1: print segfault info to
1495 the kernel console.
1496 default: off.
1498 printk.time= Show timing data prefixed to each printk message line
1499 Format: <bool> (1/Y/y=enable, 0/N/n=disable)
1501 profile= [KNL] Enable kernel profiling via /proc/profile
1502 Format: [schedule,]<number>
1503 Param: "schedule" - profile schedule points.
1504 Param: <number> - step/bucket size as a power of 2 for
1505 statistical time based profiling.
1506 Param: "sleep" - profile D-state sleeping (millisecs).
1507 Requires CONFIG_SCHEDSTATS
1508 Param: "kvm" - profile VM exits.
1510 processor.max_cstate= [HW,ACPI]
1511 Limit processor to maximum C-state
1512 max_cstate=9 overrides any DMI blacklist limit.
1514 processor.nocst [HW,ACPI]
1515 Ignore the _CST method to determine C-states,
1516 instead using the legacy FADT method
1518 prompt_ramdisk= [RAM] List of RAM disks to prompt for floppy disk
1519 before loading.
1520 See Documentation/ramdisk.txt.
1522 psmouse.proto= [HW,MOUSE] Highest PS2 mouse protocol extension to
1523 probe for; one of (bare|imps|exps|lifebook|any).
1524 psmouse.rate= [HW,MOUSE] Set desired mouse report rate, in reports
1525 per second.
1526 psmouse.resetafter= [HW,MOUSE]
1527 Try to reset the device after so many bad packets
1528 (0 = never).
1529 psmouse.resolution=
1530 [HW,MOUSE] Set desired mouse resolution, in dpi.
1531 psmouse.smartscroll=
1532 [HW,MOUSE] Controls Logitech smartscroll autorepeat.
1533 0 = disabled, 1 = enabled (default).
1535 pss= [HW,OSS] Personal Sound System (ECHO ESC614)
1536 Format:
1537 <io>,<mss_io>,<mss_irq>,<mss_dma>,<mpu_io>,<mpu_irq>
1539 pt. [PARIDE]
1540 See Documentation/paride.txt.
1542 pty.legacy_count=
1543 [KNL] Number of legacy pty's. Overwrites compiled-in
1544 default number.
1546 quiet [KNL] Disable most log messages
1548 r128= [HW,DRM]
1550 raid= [HW,RAID]
1551 See Documentation/md.txt.
1553 ramdisk_blocksize= [RAM]
1554 See Documentation/ramdisk.txt.
1556 ramdisk_size= [RAM] Sizes of RAM disks in kilobytes
1557 See Documentation/ramdisk.txt.
1559 rcu.blimit= [KNL,BOOT] Set maximum number of finished
1560 RCU callbacks to process in one batch.
1562 rcu.qhimark= [KNL,BOOT] Set threshold of queued
1563 RCU callbacks over which batch limiting is disabled.
1565 rcu.qlowmark= [KNL,BOOT] Set threshold of queued
1566 RCU callbacks below which batch limiting is re-enabled.
1568 rdinit= [KNL]
1569 Format: <full_path>
1570 Run specified binary instead of /init from the ramdisk,
1571 used for early userspace startup. See initrd.
1573 reboot= [BUGS=X86-32,BUGS=ARM,BUGS=IA-64] Rebooting mode
1574 Format: <reboot_mode>[,<reboot_mode2>[,...]]
1575 See arch/*/kernel/reboot.c or arch/*/kernel/process.c
1577 reserve= [KNL,BUGS] Force the kernel to ignore some iomem area
1579 reservetop= [X86-32]
1580 Format: nn[KMG]
1581 Reserves a hole at the top of the kernel virtual
1582 address space.
1584 reset_devices [KNL] Force drivers to reset the underlying device
1585 during initialization.
1587 resume= [SWSUSP]
1588 Specify the partition device for software suspend
1590 resume_offset= [SWSUSP]
1591 Specify the offset from the beginning of the partition
1592 given by "resume=" at which the swap header is located,
1593 in <PAGE_SIZE> units (needed only for swap files).
1594 See Documentation/power/swsusp-and-swap-files.txt
1596 retain_initrd [RAM] Keep initrd memory after extraction
1598 rhash_entries= [KNL,NET]
1599 Set number of hash buckets for route cache
1601 riscom8= [HW,SERIAL]
1602 Format: <io_board1>[,<io_board2>[,...<io_boardN>]]
1604 ro [KNL] Mount root device read-only on boot
1606 root= [KNL] Root filesystem
1608 rootdelay= [KNL] Delay (in seconds) to pause before attempting to
1609 mount the root filesystem
1611 rootflags= [KNL] Set root filesystem mount option string
1613 rootfstype= [KNL] Set root filesystem type
1615 rootwait [KNL] Wait (indefinitely) for root device to show up.
1616 Useful for devices that are detected asynchronously
1617 (e.g. USB and MMC devices).
1619 root_plug.vendor_id=
1620 [ROOTPLUG] Override the default vendor ID
1622 root_plug.product_id=
1623 [ROOTPLUG] Override the default product ID
1625 root_plug.debug=
1626 [ROOTPLUG] Enable debugging output
1628 rw [KNL] Mount root device read-write on boot
1630 S [KNL] Run init in single mode
1632 sa1100ir [NET]
1633 See drivers/net/irda/sa1100_ir.c.
1635 sbni= [NET] Granch SBNI12 leased line adapter
1637 sc1200wdt= [HW,WDT] SC1200 WDT (watchdog) driver
1638 Format: <io>[,<timeout>[,<isapnp>]]
1640 scsi_debug_*= [SCSI]
1641 See drivers/scsi/scsi_debug.c.
1643 scsi_default_dev_flags=
1644 [SCSI] SCSI default device flags
1645 Format: <integer>
1647 scsi_dev_flags= [SCSI] Black/white list entry for vendor and model
1648 Format: <vendor>:<model>:<flags>
1649 (flags are integer value)
1651 scsi_logging_level= [SCSI] a bit mask of logging levels
1652 See drivers/scsi/scsi_logging.h for bits. Also
1653 settable via sysctl at dev.scsi.logging_level
1654 (/proc/sys/dev/scsi/logging_level).
1655 There is also a nice 'scsi_logging_level' script in the
1656 S390-tools package, available for download at
1657 http://www-128.ibm.com/developerworks/linux/linux390/s390-tools-1.5.4.html
1659 scsi_mod.scan= [SCSI] sync (default) scans SCSI busses as they are
1660 discovered. async scans them in kernel threads,
1661 allowing boot to proceed. none ignores them, expecting
1662 user space to do the scan.
1664 selinux [SELINUX] Disable or enable SELinux at boot time.
1665 Format: { "0" | "1" }
1666 See security/selinux/Kconfig help text.
1667 0 -- disable.
1668 1 -- enable.
1669 Default value is set via kernel config option.
1670 If enabled at boot time, /selinux/disable can be used
1671 later to disable prior to initial policy load.
1673 selinux_compat_net =
1674 [SELINUX] Set initial selinux_compat_net flag value.
1675 Format: { "0" | "1" }
1676 0 -- use new secmark-based packet controls
1677 1 -- use legacy packet controls
1678 Default value is 0 (preferred).
1679 Value can be changed at runtime via
1680 /selinux/compat_net.
1682 serialnumber [BUGS=X86-32]
1684 shapers= [NET]
1685 Maximal number of shapers.
1687 sim710= [SCSI,HW]
1688 See header of drivers/scsi/sim710.c.
1690 simeth= [IA-64]
1691 simscsi=
1693 slram= [HW,MTD]
1695 slub_debug[=options[,slabs]] [MM, SLUB]
1696 Enabling slub_debug allows one to determine the
1697 culprit if slab objects become corrupted. Enabling
1698 slub_debug can create guard zones around objects and
1699 may poison objects when not in use. Also tracks the
1700 last alloc / free. For more information see
1701 Documentation/vm/slub.txt.
1703 slub_max_order= [MM, SLUB]
1704 Determines the maximum allowed order for slabs.
1705 A high setting may cause OOMs due to memory
1706 fragmentation. For more information see
1707 Documentation/vm/slub.txt.
1709 slub_min_objects= [MM, SLUB]
1710 The minimum number of objects per slab. SLUB will
1711 increase the slab order up to slub_max_order to
1712 generate a sufficiently large slab able to contain
1713 the number of objects indicated. The higher the number
1714 of objects the smaller the overhead of tracking slabs
1715 and the less frequently locks need to be acquired.
1716 For more information see Documentation/vm/slub.txt.
1718 slub_min_order= [MM, SLUB]
1719 Determines the mininum page order for slabs. Must be
1720 lower than slub_max_order.
1721 For more information see Documentation/vm/slub.txt.
1723 slub_nomerge [MM, SLUB]
1724 Disable merging of slabs with similar size. May be
1725 necessary if there is some reason to distinguish
1726 allocs to different slabs. Debug options disable
1727 merging on their own.
1728 For more information see Documentation/vm/slub.txt.
1730 smart2= [HW]
1731 Format: <io1>[,<io2>[,...,<io8>]]
1733 smp-alt-once [X86-32,SMP] On a hotplug CPU system, only
1734 attempt to substitute SMP alternatives once at boot.
1736 smsc-ircc2.nopnp [HW] Don't use PNP to discover SMC devices
1737 smsc-ircc2.ircc_cfg= [HW] Device configuration I/O port
1738 smsc-ircc2.ircc_sir= [HW] SIR base I/O port
1739 smsc-ircc2.ircc_fir= [HW] FIR base I/O port
1740 smsc-ircc2.ircc_irq= [HW] IRQ line
1741 smsc-ircc2.ircc_dma= [HW] DMA channel
1742 smsc-ircc2.ircc_transceiver= [HW] Transceiver type:
1743 0: Toshiba Satellite 1800 (GP data pin select)
1744 1: Fast pin select (default)
1745 2: ATC IRMode
1747 snd-ad1816a= [HW,ALSA]
1749 snd-ad1848= [HW,ALSA]
1751 snd-ali5451= [HW,ALSA]
1753 snd-als100= [HW,ALSA]
1755 snd-als4000= [HW,ALSA]
1757 snd-azt2320= [HW,ALSA]
1759 snd-cmi8330= [HW,ALSA]
1761 snd-cmipci= [HW,ALSA]
1763 snd-cs4231= [HW,ALSA]
1765 snd-cs4232= [HW,ALSA]
1767 snd-cs4236= [HW,ALSA]
1769 snd-cs4281= [HW,ALSA]
1771 snd-cs46xx= [HW,ALSA]
1773 snd-dt019x= [HW,ALSA]
1775 snd-dummy= [HW,ALSA]
1777 snd-emu10k1= [HW,ALSA]
1779 snd-ens1370= [HW,ALSA]
1781 snd-ens1371= [HW,ALSA]
1783 snd-es968= [HW,ALSA]
1785 snd-es1688= [HW,ALSA]
1787 snd-es18xx= [HW,ALSA]
1789 snd-es1938= [HW,ALSA]
1791 snd-es1968= [HW,ALSA]
1793 snd-fm801= [HW,ALSA]
1795 snd-gusclassic= [HW,ALSA]
1797 snd-gusextreme= [HW,ALSA]
1799 snd-gusmax= [HW,ALSA]
1801 snd-hdsp= [HW,ALSA]
1803 snd-ice1712= [HW,ALSA]
1805 snd-intel8x0= [HW,ALSA]
1807 snd-interwave= [HW,ALSA]
1809 snd-interwave-stb=
1810 [HW,ALSA]
1812 snd-korg1212= [HW,ALSA]
1814 snd-maestro3= [HW,ALSA]
1816 snd-mpu401= [HW,ALSA]
1818 snd-mtpav= [HW,ALSA]
1820 snd-nm256= [HW,ALSA]
1822 snd-opl3sa2= [HW,ALSA]
1824 snd-opti92x-ad1848=
1825 [HW,ALSA]
1827 snd-opti92x-cs4231=
1828 [HW,ALSA]
1830 snd-opti93x= [HW,ALSA]
1832 snd-pmac= [HW,ALSA]
1834 snd-rme32= [HW,ALSA]
1836 snd-rme96= [HW,ALSA]
1838 snd-rme9652= [HW,ALSA]
1840 snd-sb8= [HW,ALSA]
1842 snd-sb16= [HW,ALSA]
1844 snd-sbawe= [HW,ALSA]
1846 snd-serial= [HW,ALSA]
1848 snd-sgalaxy= [HW,ALSA]
1850 snd-sonicvibes= [HW,ALSA]
1852 snd-sun-amd7930=
1853 [HW,ALSA]
1855 snd-sun-cs4231= [HW,ALSA]
1857 snd-trident= [HW,ALSA]
1859 snd-usb-audio= [HW,ALSA,USB]
1861 snd-via82xx= [HW,ALSA]
1863 snd-virmidi= [HW,ALSA]
1865 snd-wavefront= [HW,ALSA]
1867 snd-ymfpci= [HW,ALSA]
1869 sonypi.*= [HW] Sony Programmable I/O Control Device driver
1870 See Documentation/sonypi.txt
1872 specialix= [HW,SERIAL] Specialix multi-serial port adapter
1873 See Documentation/specialix.txt.
1875 spia_io_base= [HW,MTD]
1876 spia_fio_base=
1877 spia_pedr=
1878 spia_peddr=
1880 sscape= [HW,OSS]
1881 Format: <io>,<irq>,<dma>,<mpu_io>,<mpu_irq>
1883 st= [HW,SCSI] SCSI tape parameters (buffers, etc.)
1884 See Documentation/scsi/st.txt.
1886 st0x= [HW,SCSI]
1887 See header of drivers/scsi/seagate.c.
1889 sti= [PARISC,HW]
1890 Format: <num>
1891 Set the STI (builtin display/keyboard on the HP-PARISC
1892 machines) console (graphic card) which should be used
1893 as the initial boot-console.
1894 See also comment in drivers/video/console/sticore.c.
1896 sti_font= [HW]
1897 See comment in drivers/video/console/sticore.c.
1899 stifb= [HW]
1900 Format: bpp:<bpp1>[:<bpp2>[:<bpp3>...]]
1902 sunrpc.pool_mode=
1903 [NFS]
1904 Control how the NFS server code allocates CPUs to
1905 service thread pools. Depending on how many NICs
1906 you have and where their interrupts are bound, this
1907 option will affect which CPUs will do NFS serving.
1908 Note: this parameter cannot be changed while the
1909 NFS server is running.
1911 auto the server chooses an appropriate mode
1912 automatically using heuristics
1913 global a single global pool contains all CPUs
1914 percpu one pool for each CPU
1915 pernode one pool for each NUMA node (equivalent
1916 to global on non-NUMA machines)
1918 swiotlb= [IA-64] Number of I/O TLB slabs
1920 switches= [HW,M68k]
1922 sym53c416= [HW,SCSI]
1923 See header of drivers/scsi/sym53c416.c.
1925 sysrq_always_enabled
1926 [KNL]
1927 Ignore sysrq setting - this boot parameter will
1928 neutralize any effect of /proc/sys/kernel/sysrq.
1929 Useful for debugging.
1931 t128= [HW,SCSI]
1932 See header of drivers/scsi/t128.c.
1934 tdfx= [HW,DRM]
1936 thash_entries= [KNL,NET]
1937 Set number of hash buckets for TCP connection
1939 thermal.act= [HW,ACPI]
1940 -1: disable all active trip points in all thermal zones
1941 <degrees C>: override all lowest active trip points
1943 thermal.crt= [HW,ACPI]
1944 -1: disable all critical trip points in all thermal zones
1945 <degrees C>: lower all critical trip points
1947 thermal.nocrt= [HW,ACPI]
1948 Set to disable actions on ACPI thermal zone
1949 critical and hot trip points.
1951 thermal.off= [HW,ACPI]
1952 1: disable ACPI thermal control
1954 thermal.psv= [HW,ACPI]
1955 -1: disable all passive trip points
1956 <degrees C>: override all passive trip points to this value
1958 thermal.tzp= [HW,ACPI]
1959 Specify global default ACPI thermal zone polling rate
1960 <deci-seconds>: poll all this frequency
1961 0: no polling (default)
1963 time Show timing data prefixed to each printk message line
1964 [deprecated, see 'printk.time']
1966 tipar.timeout= [HW,PPT]
1967 Set communications timeout in tenths of a second
1968 (default 15).
1970 tipar.delay= [HW,PPT]
1971 Set inter-bit delay in microseconds (default 10).
1973 tmc8xx= [HW,SCSI]
1974 See header of drivers/scsi/seagate.c.
1976 tmscsim= [HW,SCSI]
1977 See comment before function dc390_setup() in
1978 drivers/scsi/tmscsim.c.
1980 tp720= [HW,PS2]
1982 trix= [HW,OSS] MediaTrix AudioTrix Pro
1983 Format:
1984 <io>,<irq>,<dma>,<dma2>,<sb_io>,<sb_irq>,<sb_dma>,<mpu_io>,<mpu_irq>
1986 turbografx.map[2|3]= [HW,JOY]
1987 TurboGraFX parallel port interface
1988 Format:
1989 <port#>,<js1>,<js2>,<js3>,<js4>,<js5>,<js6>,<js7>
1990 See also Documentation/input/joystick-parport.txt
1992 u14-34f= [HW,SCSI] UltraStor 14F/34F SCSI host adapter
1993 See header of drivers/scsi/u14-34f.c.
1995 uart401= [HW,OSS]
1996 Format: <io>,<irq>
1998 uart6850= [HW,OSS]
1999 Format: <io>,<irq>
2001 uhci-hcd.ignore_oc=
2002 [USB] Ignore overcurrent events (default N).
2003 Some badly-designed motherboards generate lots of
2004 bogus events, for ports that aren't wired to
2005 anything. Set this parameter to avoid log spamming.
2006 Note that genuine overcurrent events won't be
2007 reported either.
2009 usbcore.autosuspend=
2010 [USB] The autosuspend time delay (in seconds) used
2011 for newly-detected USB devices (default 2). This
2012 is the time required before an idle device will be
2013 autosuspended. Devices for which the delay is set
2014 to a negative value won't be autosuspended at all.
2016 usbhid.mousepoll=
2017 [USBHID] The interval which mice are to be polled at.
2019 vdso= [X86-32,SH,x86-64]
2020 vdso=2: enable compat VDSO (default with COMPAT_VDSO)
2021 vdso=1: enable VDSO (default)
2022 vdso=0: disable VDSO mapping
2024 vdso32= [X86-32,X86-64]
2025 vdso32=2: enable compat VDSO (default with COMPAT_VDSO)
2026 vdso32=1: enable 32-bit VDSO (default)
2027 vdso32=0: disable 32-bit VDSO mapping
2029 vector= [IA-64,SMP]
2030 vector=percpu: enable percpu vector domain
2032 video= [FB] Frame buffer configuration
2033 See Documentation/fb/modedb.txt.
2035 vga= [BOOT,X86-32] Select a particular video mode
2036 See Documentation/i386/boot.txt and
2037 Documentation/svga.txt.
2038 Use vga=ask for menu.
2039 This is actually a boot loader parameter; the value is
2040 passed to the kernel using a special protocol.
2042 vmalloc=nn[KMG] [KNL,BOOT] Forces the vmalloc area to have an exact
2043 size of <nn>. This can be used to increase the
2044 minimum size (128MB on x86). It can also be used to
2045 decrease the size and leave more room for directly
2046 mapped kernel RAM.
2048 vmhalt= [KNL,S390] Perform z/VM CP command after system halt.
2049 Format: <command>
2051 vmpanic= [KNL,S390] Perform z/VM CP command after kernel panic.
2052 Format: <command>
2054 vmpoff= [KNL,S390] Perform z/VM CP command after power off.
2055 Format: <command>
2057 waveartist= [HW,OSS]
2058 Format: <io>,<irq>,<dma>,<dma2>
2060 wd33c93= [HW,SCSI]
2061 See header of drivers/scsi/wd33c93.c.
2063 wd7000= [HW,SCSI]
2064 See header of drivers/scsi/wd7000.c.
2066 wdt= [WDT] Watchdog
2067 See Documentation/watchdog/wdt.txt.
2069 xd= [HW,XT] Original XT pre-IDE (RLL encoded) disks.
2070 xd_geo= See header of drivers/block/xd.c.
2072 xirc2ps_cs= [NET,PCMCIA]
2073 Format:
2074 <irq>,<irq_mask>,<io>,<full_duplex>,<do_sound>,<lockup_hack>[,<irq2>[,<irq3>[,<irq4>]]]
2076 norandmaps Don't use address space randomization
2077 Equivalent to echo 0 > /proc/sys/kernel/randomize_va_space
2079 ______________________________________________________________________
2081 TODO:
2083 Add documentation for ALSA options.
2084 Add more DRM drivers.