| blob | 5d171b7b8393b95c857f9aad5945939a2c999e21 |
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.
721 i8042.direct [HW] Put keyboard port into non-translated mode
722 i8042.dumbkbd [HW] Pretend that controller can only read data from
723 keyboard and cannot control its state
724 (Don't attempt to blink the leds)
725 i8042.noaux [HW] Don't check for auxiliary (== mouse) port
726 i8042.nokbd [HW] Don't check/create keyboard port
727 i8042.nomux [HW] Don't check presence of an active multiplexing
728 controller
729 i8042.nopnp [HW] Don't use ACPIPnP / PnPBIOS to discover KBD/AUX
730 controllers
731 i8042.panicblink=
732 [HW] Frequency with which keyboard LEDs should blink
733 when kernel panics (default is 0.5 sec)
734 i8042.reset [HW] Reset the controller during init and cleanup
735 i8042.unlock [HW] Unlock (ignore) the keylock
737 i810= [HW,DRM]
739 i8k.ignore_dmi [HW] Continue probing hardware even if DMI data
740 indicates that the driver is running on unsupported
741 hardware.
742 i8k.force [HW] Activate i8k driver even if SMM BIOS signature
743 does not match list of supported models.
744 i8k.power_status
745 [HW] Report power status in /proc/i8k
746 (disabled by default)
747 i8k.restricted [HW] Allow controlling fans only if SYS_ADMIN
748 capability is set.
750 ibmmcascsi= [HW,MCA,SCSI] IBM MicroChannel SCSI adapter
751 See Documentation/mca.txt.
753 icn= [HW,ISDN]
754 Format: <io>[,<membase>[,<icn_id>[,<icn_id2>]]]
756 ide= [HW] (E)IDE subsystem
757 Format: ide=nodma or ide=doubler or ide=reverse
758 See Documentation/ide.txt.
760 ide?= [HW] (E)IDE subsystem
761 Format: ide?=noprobe or chipset specific parameters.
762 See Documentation/ide.txt.
764 idebus= [HW] (E)IDE subsystem - VLB/PCI bus speed
765 See Documentation/ide.txt.
767 idle= [X86]
768 Format: idle=poll or idle=mwait
769 Poll forces a polling idle loop that can slightly improves the performance
770 of waking up a idle CPU, but will use a lot of power and make the system
771 run hot. Not recommended.
772 idle=mwait. On systems which support MONITOR/MWAIT but the kernel chose
773 to not use it because it doesn't save as much power as a normal idle
774 loop use the MONITOR/MWAIT idle loop anyways. Performance should be the same
775 as idle=poll.
777 ignore_loglevel [KNL]
778 Ignore loglevel setting - this will print /all/
779 kernel messages to the console. Useful for debugging.
781 ihash_entries= [KNL]
782 Set number of hash buckets for inode cache.
784 in2000= [HW,SCSI]
785 See header of drivers/scsi/in2000.c.
787 init= [KNL]
788 Format: <full_path>
789 Run specified binary instead of /sbin/init as init
790 process.
792 initcall_debug [KNL] Trace initcalls as they are executed. Useful
793 for working out where the kernel is dying during
794 startup.
796 initrd= [BOOT] Specify the location of the initial ramdisk
798 inport.irq= [HW] Inport (ATI XL and Microsoft) busmouse driver
799 Format: <irq>
801 inttest= [IA64]
803 intel_iommu= [DMAR] Intel IOMMU driver (DMAR) option
804 off
805 Disable intel iommu driver.
806 igfx_off [Default Off]
807 By default, gfx is mapped as normal device. If a gfx
808 device has a dedicated DMAR unit, the DMAR unit is
809 bypassed by not enabling DMAR with this option. In
810 this case, gfx device will use physical address for
811 DMA.
812 forcedac [x86_64]
813 With this option iommu will not optimize to look
814 for io virtual address below 32 bit forcing dual
815 address cycle on pci bus for cards supporting greater
816 than 32 bit addressing. The default is to look
817 for translation below 32 bit and if not available
818 then look in the higher range.
820 io_delay= [X86-32,X86-64] I/O delay method
821 0x80
822 Standard port 0x80 based delay
823 0xed
824 Alternate port 0xed based delay (needed on some systems)
825 udelay
826 Simple two microseconds delay
827 none
828 No delay
830 io7= [HW] IO7 for Marvel based alpha systems
831 See comment before marvel_specify_io7 in
832 arch/alpha/kernel/core_marvel.c.
834 ip= [IP_PNP]
835 See Documentation/nfsroot.txt.
837 ip2= [HW] Set IO/IRQ pairs for up to 4 IntelliPort boards
838 See comment before ip2_setup() in
839 drivers/char/ip2/ip2base.c.
841 ips= [HW,SCSI] Adaptec / IBM ServeRAID controller
842 See header of drivers/scsi/ips.c.
844 ports= [IP_VS_FTP] IPVS ftp helper module
845 Default is 21.
846 Up to 8 (IP_VS_APP_MAX_PORTS) ports
847 may be specified.
848 Format: <port>,<port>....
850 irqfixup [HW]
851 When an interrupt is not handled search all handlers
852 for it. Intended to get systems with badly broken
853 firmware running.
855 irqpoll [HW]
856 When an interrupt is not handled search all handlers
857 for it. Also check all handlers each timer
858 interrupt. Intended to get systems with badly broken
859 firmware running.
861 isapnp= [ISAPNP]
862 Format: <RDP>,<reset>,<pci_scan>,<verbosity>
864 isolcpus= [KNL,SMP] Isolate CPUs from the general scheduler.
865 Format:
866 <cpu number>,...,<cpu number>
867 or
868 <cpu number>-<cpu number> (must be a positive range in ascending order)
869 or a mixture
870 <cpu number>,...,<cpu number>-<cpu number>
871 This option can be used to specify one or more CPUs
872 to isolate from the general SMP balancing and scheduling
873 algorithms. The only way to move a process onto or off
874 an "isolated" CPU is via the CPU affinity syscalls.
875 <cpu number> begins at 0 and the maximum value is
876 "number of CPUs in system - 1".
878 This option is the preferred way to isolate CPUs. The
879 alternative -- manually setting the CPU mask of all
880 tasks in the system -- can cause problems and
881 suboptimal load balancer performance.
883 iucv= [HW,NET]
885 js= [HW,JOY] Analog joystick
886 See Documentation/input/joystick.txt.
888 kernelcore=nn[KMG] [KNL,X86-32,IA-64,PPC,X86-64] This parameter
889 specifies the amount of memory usable by the kernel
890 for non-movable allocations. The requested amount is
891 spread evenly throughout all nodes in the system. The
892 remaining memory in each node is used for Movable
893 pages. In the event, a node is too small to have both
894 kernelcore and Movable pages, kernelcore pages will
895 take priority and other nodes will have a larger number
896 of kernelcore pages. The Movable zone is used for the
897 allocation of pages that may be reclaimed or moved
898 by the page migration subsystem. This means that
899 HugeTLB pages may not be allocated from this zone.
900 Note that allocations like PTEs-from-HighMem still
901 use the HighMem zone if it exists, and the Normal
902 zone if it does not.
904 movablecore=nn[KMG] [KNL,X86-32,IA-64,PPC,X86-64] This parameter
905 is similar to kernelcore except it specifies the
906 amount of memory used for migratable allocations.
907 If both kernelcore and movablecore is specified,
908 then kernelcore will be at *least* the specified
909 value but may be more. If movablecore on its own
910 is specified, the administrator must be careful
911 that the amount of memory usable for all allocations
912 is not too small.
914 keepinitrd [HW,ARM]
916 kstack=N [X86-32,X86-64] Print N words from the kernel stack
917 in oops dumps.
919 l2cr= [PPC]
921 lapic [X86-32,APIC] Enable the local APIC even if BIOS
922 disabled it.
924 lapic_timer_c2_ok [X86-32,x86-64,APIC] trust the local apic timer in
925 C2 power state.
927 libata.dma= [LIBATA] DMA control
928 libata.dma=0 Disable all PATA and SATA DMA
929 libata.dma=1 PATA and SATA Disk DMA only
930 libata.dma=2 ATAPI (CDROM) DMA only
931 libata.dma=4 Compact Flash DMA only
932 Combinations also work, so libata.dma=3 enables DMA
933 for disks and CDROMs, but not CFs.
935 libata.noacpi [LIBATA] Disables use of ACPI in libata suspend/resume
936 when set.
937 Format: <int>
939 load_ramdisk= [RAM] List of ramdisks to load from floppy
940 See Documentation/ramdisk.txt.
942 lockd.nlm_grace_period=P [NFS] Assign grace period.
943 Format: <integer>
945 lockd.nlm_tcpport=N [NFS] Assign TCP port.
946 Format: <integer>
948 lockd.nlm_timeout=T [NFS] Assign timeout value.
949 Format: <integer>
951 lockd.nlm_udpport=M [NFS] Assign UDP port.
952 Format: <integer>
954 logibm.irq= [HW,MOUSE] Logitech Bus Mouse Driver
955 Format: <irq>
957 loglevel= All Kernel Messages with a loglevel smaller than the
958 console loglevel will be printed to the console. It can
959 also be changed with klogd or other programs. The
960 loglevels are defined as follows:
962 0 (KERN_EMERG) system is unusable
963 1 (KERN_ALERT) action must be taken immediately
964 2 (KERN_CRIT) critical conditions
965 3 (KERN_ERR) error conditions
966 4 (KERN_WARNING) warning conditions
967 5 (KERN_NOTICE) normal but significant condition
968 6 (KERN_INFO) informational
969 7 (KERN_DEBUG) debug-level messages
971 log_buf_len=n Sets the size of the printk ring buffer, in bytes.
972 Format: { n | nk | nM }
973 n must be a power of two. The default size
974 is set in the kernel config file.
976 logo.nologo [FB] Disables display of the built-in Linux logo.
977 This may be used to provide more screen space for
978 kernel log messages and is useful when debugging
979 kernel boot problems.
981 lp=0 [LP] Specify parallel ports to use, e.g,
982 lp=port[,port...] lp=none,parport0 (lp0 not configured, lp1 uses
983 lp=reset first parallel port). 'lp=0' disables the
984 lp=auto printer driver. 'lp=reset' (which can be
985 specified in addition to the ports) causes
986 attached printers to be reset. Using
987 lp=port1,port2,... specifies the parallel ports
988 to associate lp devices with, starting with
989 lp0. A port specification may be 'none' to skip
990 that lp device, or a parport name such as
991 'parport0'. Specifying 'lp=auto' instead of a
992 port specification list means that device IDs
993 from each port should be examined, to see if
994 an IEEE 1284-compliant printer is attached; if
995 so, the driver will manage that printer.
996 See also header of drivers/char/lp.c.
998 lpj=n [KNL]
999 Sets loops_per_jiffy to given constant, thus avoiding
1000 time-consuming boot-time autodetection (up to 250 ms per
1001 CPU). 0 enables autodetection (default). To determine
1002 the correct value for your kernel, boot with normal
1003 autodetection and see what value is printed. Note that
1004 on SMP systems the preset will be applied to all CPUs,
1005 which is likely to cause problems if your CPUs need
1006 significantly divergent settings. An incorrect value
1007 will cause delays in the kernel to be wrong, leading to
1008 unpredictable I/O errors and other breakage. Although
1009 unlikely, in the extreme case this might damage your
1010 hardware.
1012 ltpc= [NET]
1013 Format: <io>,<irq>,<dma>
1015 mac5380= [HW,SCSI] Format:
1016 <can_queue>,<cmd_per_lun>,<sg_tablesize>,<hostid>,<use_tags>
1018 mac53c9x= [HW,SCSI] Format:
1019 <num_esps>,<disconnect>,<nosync>,<can_queue>,<cmd_per_lun>,<sg_tablesize>,<hostid>,<use_tags>
1021 machvec= [IA64] Force the use of a particular machine-vector
1022 (machvec) in a generic kernel.
1023 Example: machvec=hpzx1_swiotlb
1025 max_loop= [LOOP] Maximum number of loopback devices that can
1026 be mounted
1027 Format: <1-256>
1029 maxcpus= [SMP] Maximum number of processors that an SMP kernel
1030 should make use of. maxcpus=n : n >= 0 limits the
1031 kernel to using 'n' processors. n=0 is a special case,
1032 it is equivalent to "nosmp", which also disables
1033 the IO APIC.
1035 max_addr=[KMG] [KNL,BOOT,ia64] All physical memory greater than or
1036 equal to this physical address is ignored.
1038 max_luns= [SCSI] Maximum number of LUNs to probe.
1039 Should be between 1 and 2^32-1.
1041 max_report_luns=
1042 [SCSI] Maximum number of LUNs received.
1043 Should be between 1 and 16384.
1045 mca-pentium [BUGS=X86-32]
1047 mcatest= [IA-64]
1049 mce [X86-32] Machine Check Exception
1051 mce=option [X86-64] See Documentation/x86_64/boot-options.txt
1053 md= [HW] RAID subsystems devices and level
1054 See Documentation/md.txt.
1056 mdacon= [MDA]
1057 Format: <first>,<last>
1058 Specifies range of consoles to be captured by the MDA.
1060 mem=nn[KMG] [KNL,BOOT] Force usage of a specific amount of memory
1061 Amount of memory to be used when the kernel is not able
1062 to see the whole system memory or for test.
1063 [X86-32] Use together with memmap= to avoid physical
1064 address space collisions. Without memmap= PCI devices
1065 could be placed at addresses belonging to unused RAM.
1067 mem=nopentium [BUGS=X86-32] Disable usage of 4MB pages for kernel
1068 memory.
1070 memmap=exactmap [KNL,X86-32,X86_64] Enable setting of an exact
1071 E820 memory map, as specified by the user.
1072 Such memmap=exactmap lines can be constructed based on
1073 BIOS output or other requirements. See the memmap=nn@ss
1074 option description.
1076 memmap=nn[KMG]@ss[KMG]
1077 [KNL] Force usage of a specific region of memory
1078 Region of memory to be used, from ss to ss+nn.
1080 memmap=nn[KMG]#ss[KMG]
1081 [KNL,ACPI] Mark specific memory as ACPI data.
1082 Region of memory to be used, from ss to ss+nn.
1084 memmap=nn[KMG]$ss[KMG]
1085 [KNL,ACPI] Mark specific memory as reserved.
1086 Region of memory to be used, from ss to ss+nn.
1088 meye.*= [HW] Set MotionEye Camera parameters
1089 See Documentation/video4linux/meye.txt.
1091 mfgpt_irq= [IA-32] Specify the IRQ to use for the
1092 Multi-Function General Purpose Timers on AMD Geode
1093 platforms.
1095 mfgptfix [X86-32] Fix MFGPT timers on AMD Geode platforms when
1096 the BIOS has incorrectly applied a workaround. TinyBIOS
1097 version 0.98 is known to be affected, 0.99 fixes the
1098 problem by letting the user disable the workaround.
1100 mga= [HW,DRM]
1102 mousedev.tap_time=
1103 [MOUSE] Maximum time between finger touching and
1104 leaving touchpad surface for touch to be considered
1105 a tap and be reported as a left button click (for
1106 touchpads working in absolute mode only).
1107 Format: <msecs>
1108 mousedev.xres= [MOUSE] Horizontal screen resolution, used for devices
1109 reporting absolute coordinates, such as tablets
1110 mousedev.yres= [MOUSE] Vertical screen resolution, used for devices
1111 reporting absolute coordinates, such as tablets
1113 mpu401= [HW,OSS]
1114 Format: <io>,<irq>
1116 MTD_Partition= [MTD]
1117 Format: <name>,<region-number>,<size>,<offset>
1119 MTD_Region= [MTD] Format:
1120 <name>,<region-number>[,<base>,<size>,<buswidth>,<altbuswidth>]
1122 mtdparts= [MTD]
1123 See drivers/mtd/cmdlinepart.c.
1125 mtouchusb.raw_coordinates=
1126 [HW] Make the MicroTouch USB driver use raw coordinates
1127 ('y', default) or cooked coordinates ('n')
1129 n2= [NET] SDL Inc. RISCom/N2 synchronous serial card
1131 NCR_D700= [HW,SCSI]
1132 See header of drivers/scsi/NCR_D700.c.
1134 ncr5380= [HW,SCSI]
1136 ncr53c400= [HW,SCSI]
1138 ncr53c400a= [HW,SCSI]
1140 ncr53c406a= [HW,SCSI]
1142 ncr53c8xx= [HW,SCSI]
1144 netdev= [NET] Network devices parameters
1145 Format: <irq>,<io>,<mem_start>,<mem_end>,<name>
1146 Note that mem_start is often overloaded to mean
1147 something different and driver-specific.
1148 This usage is only documented in each driver source
1149 file if at all.
1151 nfsaddrs= [NFS]
1152 See Documentation/nfsroot.txt.
1154 nfsroot= [NFS] nfs root filesystem for disk-less boxes.
1155 See Documentation/nfsroot.txt.
1157 nfs.callback_tcpport=
1158 [NFS] set the TCP port on which the NFSv4 callback
1159 channel should listen.
1161 nfs.idmap_cache_timeout=
1162 [NFS] set the maximum lifetime for idmapper cache
1163 entries.
1165 nfs.enable_ino64=
1166 [NFS] enable 64-bit inode numbers.
1167 If zero, the NFS client will fake up a 32-bit inode
1168 number for the readdir() and stat() syscalls instead
1169 of returning the full 64-bit number.
1170 The default is to return 64-bit inode numbers.
1172 nmi_debug= [KNL,AVR32] Specify one or more actions to take
1173 when a NMI is triggered.
1174 Format: [state][,regs][,debounce][,die]
1176 nmi_watchdog= [KNL,BUGS=X86-32] Debugging features for SMP kernels
1178 no387 [BUGS=X86-32] Tells the kernel to use the 387 maths
1179 emulation library even if a 387 maths coprocessor
1180 is present.
1182 noaliencache [MM, NUMA, SLAB] Disables the allocation of alien
1183 caches in the slab allocator. Saves per-node memory,
1184 but will impact performance.
1186 noalign [KNL,ARM]
1188 noapic [SMP,APIC] Tells the kernel to not make use of any
1189 IOAPICs that may be present in the system.
1191 nobats [PPC] Do not use BATs for mapping kernel lowmem
1192 on "Classic" PPC cores.
1194 nocache [ARM]
1196 nodelayacct [KNL] Disable per-task delay accounting
1198 nodisconnect [HW,SCSI,M68K] Disables SCSI disconnects.
1200 noefi [X86-32,X86-64] Disable EFI runtime services support.
1202 noexec [IA-64]
1204 noexec [X86-32,X86-64]
1205 noexec=on: enable non-executable mappings (default)
1206 noexec=off: disable nn-executable mappings
1208 nofxsr [BUGS=X86-32] Disables x86 floating point extended
1209 register save and restore. The kernel will only save
1210 legacy floating-point registers on task switch.
1212 noclflush [BUGS=X86] Don't use the CLFLUSH instruction
1214 nohlt [BUGS=ARM]
1216 no-hlt [BUGS=X86-32] Tells the kernel that the hlt
1217 instruction doesn't work correctly and not to
1218 use it.
1220 nohalt [IA-64] Tells the kernel not to use the power saving
1221 function PAL_HALT_LIGHT when idle. This increases
1222 power-consumption. On the positive side, it reduces
1223 interrupt wake-up latency, which may improve performance
1224 in certain environments such as networked servers or
1225 real-time systems.
1227 nohz= [KNL] Boottime enable/disable dynamic ticks
1228 Valid arguments: on, off
1229 Default: on
1231 noirqbalance [X86-32,SMP,KNL] Disable kernel irq balancing
1233 noirqdebug [X86-32] Disables the code which attempts to detect and
1234 disable unhandled interrupt sources.
1236 no_timer_check [X86-32,X86_64,APIC] Disables the code which tests for
1237 broken timer IRQ sources.
1239 noisapnp [ISAPNP] Disables ISA PnP code.
1241 noinitrd [RAM] Tells the kernel not to load any configured
1242 initial RAM disk.
1244 nointroute [IA-64]
1246 nojitter [IA64] Disables jitter checking for ITC timers.
1248 nolapic [X86-32,APIC] Do not enable or use the local APIC.
1250 nolapic_timer [X86-32,APIC] Do not use the local APIC timer.
1252 noltlbs [PPC] Do not use large page/tlb entries for kernel
1253 lowmem mapping on PPC40x.
1255 nomca [IA-64] Disable machine check abort handling
1257 nomce [X86-32] Machine Check Exception
1259 nomfgpt [X86-32] Disable Multi-Function General Purpose
1260 Timer usage (for AMD Geode machines).
1262 noreplace-paravirt [X86-32,PV_OPS] Don't patch paravirt_ops
1264 noreplace-smp [X86-32,SMP] Don't replace SMP instructions
1265 with UP alternatives
1267 noresidual [PPC] Don't use residual data on PReP machines.
1269 noresume [SWSUSP] Disables resume and restores original swap
1270 space.
1272 no-scroll [VGA] Disables scrollback.
1273 This is required for the Braillex ib80-piezo Braille
1274 reader made by F.H. Papenmeier (Germany).
1276 nosbagart [IA-64]
1278 nosep [BUGS=X86-32] Disables x86 SYSENTER/SYSEXIT support.
1280 nosmp [SMP] Tells an SMP kernel to act as a UP kernel,
1281 and disable the IO APIC. legacy for "maxcpus=0".
1283 nosoftlockup [KNL] Disable the soft-lockup detector.
1285 nosync [HW,M68K] Disables sync negotiation for all devices.
1287 notsc [BUGS=X86-32] Disable Time Stamp Counter
1289 nousb [USB] Disable the USB subsystem
1291 nowb [ARM]
1293 numa_zonelist_order= [KNL, BOOT] Select zonelist order for NUMA.
1294 one of ['zone', 'node', 'default'] can be specified
1295 This can be set from sysctl after boot.
1296 See Documentation/sysctl/vm.txt for details.
1298 nr_uarts= [SERIAL] maximum number of UARTs to be registered.
1300 opl3= [HW,OSS]
1301 Format: <io>
1303 oprofile.timer= [HW]
1304 Use timer interrupt instead of performance counters
1306 osst= [HW,SCSI] SCSI Tape Driver
1307 Format: <buffer_size>,<write_threshold>
1308 See also Documentation/scsi/st.txt.
1310 panic= [KNL] Kernel behaviour on panic
1311 Format: <timeout>
1313 parkbd.port= [HW] Parallel port number the keyboard adapter is
1314 connected to, default is 0.
1315 Format: <parport#>
1316 parkbd.mode= [HW] Parallel port keyboard adapter mode of operation,
1317 0 for XT, 1 for AT (default is AT).
1318 Format: <mode>
1320 parport= [HW,PPT] Specify parallel ports. 0 disables.
1321 Format: { 0 | auto | 0xBBB[,IRQ[,DMA]] }
1322 Use 'auto' to force the driver to use any
1323 IRQ/DMA settings detected (the default is to
1324 ignore detected IRQ/DMA settings because of
1325 possible conflicts). You can specify the base
1326 address, IRQ, and DMA settings; IRQ and DMA
1327 should be numbers, or 'auto' (for using detected
1328 settings on that particular port), or 'nofifo'
1329 (to avoid using a FIFO even if it is detected).
1330 Parallel ports are assigned in the order they
1331 are specified on the command line, starting
1332 with parport0.
1334 parport_init_mode= [HW,PPT]
1335 Configure VIA parallel port to operate in
1336 a specific mode. This is necessary on Pegasos
1337 computer where firmware has no options for setting
1338 up parallel port mode and sets it to spp.
1339 Currently this function knows 686a and 8231 chips.
1340 Format: [spp|ps2|epp|ecp|ecpepp]
1342 pas2= [HW,OSS] Format:
1343 <io>,<irq>,<dma>,<dma16>,<sb_io>,<sb_irq>,<sb_dma>,<sb_dma16>
1345 pas16= [HW,SCSI]
1346 See header of drivers/scsi/pas16.c.
1348 pause_on_oops=
1349 Halt all CPUs after the first oops has been printed for
1350 the specified number of seconds. This is to be used if
1351 your oopses keep scrolling off the screen.
1353 pcbit= [HW,ISDN]
1355 pcd. [PARIDE]
1356 See header of drivers/block/paride/pcd.c.
1357 See also Documentation/paride.txt.
1359 pci=option[,option...] [PCI] various PCI subsystem options:
1360 off [X86-32] don't probe for the PCI bus
1361 bios [X86-32] force use of PCI BIOS, don't access
1362 the hardware directly. Use this if your machine
1363 has a non-standard PCI host bridge.
1364 nobios [X86-32] disallow use of PCI BIOS, only direct
1365 hardware access methods are allowed. Use this
1366 if you experience crashes upon bootup and you
1367 suspect they are caused by the BIOS.
1368 conf1 [X86-32] Force use of PCI Configuration
1369 Mechanism 1.
1370 conf2 [X86-32] Force use of PCI Configuration
1371 Mechanism 2.
1372 noaer [PCIE] If the PCIEAER kernel config parameter is
1373 enabled, this kernel boot option can be used to
1374 disable the use of PCIE advanced error reporting.
1375 nodomains [PCI] Disable support for multiple PCI
1376 root domains (aka PCI segments, in ACPI-speak).
1377 nommconf [X86-32,X86_64] Disable use of MMCONFIG for PCI
1378 Configuration
1379 nomsi [MSI] If the PCI_MSI kernel config parameter is
1380 enabled, this kernel boot option can be used to
1381 disable the use of MSI interrupts system-wide.
1382 nosort [X86-32] Don't sort PCI devices according to
1383 order given by the PCI BIOS. This sorting is
1384 done to get a device order compatible with
1385 older kernels.
1386 biosirq [X86-32] Use PCI BIOS calls to get the interrupt
1387 routing table. These calls are known to be buggy
1388 on several machines and they hang the machine
1389 when used, but on other computers it's the only
1390 way to get the interrupt routing table. Try
1391 this option if the kernel is unable to allocate
1392 IRQs or discover secondary PCI buses on your
1393 motherboard.
1394 rom [X86-32] Assign address space to expansion ROMs.
1395 Use with caution as certain devices share
1396 address decoders between ROMs and other
1397 resources.
1398 irqmask=0xMMMM [X86-32] Set a bit mask of IRQs allowed to be
1399 assigned automatically to PCI devices. You can
1400 make the kernel exclude IRQs of your ISA cards
1401 this way.
1402 pirqaddr=0xAAAAA [X86-32] Specify the physical address
1403 of the PIRQ table (normally generated
1404 by the BIOS) if it is outside the
1405 F0000h-100000h range.
1406 lastbus=N [X86-32] Scan all buses thru bus #N. Can be
1407 useful if the kernel is unable to find your
1408 secondary buses and you want to tell it
1409 explicitly which ones they are.
1410 assign-busses [X86-32] Always assign all PCI bus
1411 numbers ourselves, overriding
1412 whatever the firmware may have done.
1413 usepirqmask [X86-32] Honor the possible IRQ mask stored
1414 in the BIOS $PIR table. This is needed on
1415 some systems with broken BIOSes, notably
1416 some HP Pavilion N5400 and Omnibook XE3
1417 notebooks. This will have no effect if ACPI
1418 IRQ routing is enabled.
1419 noacpi [X86-32] Do not use ACPI for IRQ routing
1420 or for PCI scanning.
1421 use_crs [X86-32] Use _CRS for PCI resource
1422 allocation.
1423 routeirq Do IRQ routing for all PCI devices.
1424 This is normally done in pci_enable_device(),
1425 so this option is a temporary workaround
1426 for broken drivers that don't call it.
1427 firmware [ARM] Do not re-enumerate the bus but instead
1428 just use the configuration from the
1429 bootloader. This is currently used on
1430 IXP2000 systems where the bus has to be
1431 configured a certain way for adjunct CPUs.
1432 noearly [X86] Don't do any early type 1 scanning.
1433 This might help on some broken boards which
1434 machine check when some devices' config space
1435 is read. But various workarounds are disabled
1436 and some IOMMU drivers will not work.
1437 bfsort Sort PCI devices into breadth-first order.
1438 This sorting is done to get a device
1439 order compatible with older (<= 2.4) kernels.
1440 nobfsort Don't sort PCI devices into breadth-first order.
1441 cbiosize=nn[KMG] The fixed amount of bus space which is
1442 reserved for the CardBus bridge's IO window.
1443 The default value is 256 bytes.
1444 cbmemsize=nn[KMG] The fixed amount of bus space which is
1445 reserved for the CardBus bridge's memory
1446 window. The default value is 64 megabytes.
1448 pcmv= [HW,PCMCIA] BadgePAD 4
1450 pd. [PARIDE]
1451 See Documentation/paride.txt.
1453 pdcchassis= [PARISC,HW] Disable/Enable PDC Chassis Status codes at
1454 boot time.
1455 Format: { 0 | 1 }
1456 See arch/parisc/kernel/pdc_chassis.c
1458 pf. [PARIDE]
1459 See Documentation/paride.txt.
1461 pg. [PARIDE]
1462 See Documentation/paride.txt.
1464 pirq= [SMP,APIC] Manual mp-table setup
1465 See Documentation/i386/IO-APIC.txt.
1467 plip= [PPT,NET] Parallel port network link
1468 Format: { parport<nr> | timid | 0 }
1469 See also Documentation/parport.txt.
1471 pnpacpi= [ACPI]
1472 { off }
1474 pnpbios= [ISAPNP]
1475 { on | off | curr | res | no-curr | no-res }
1477 pnp_reserve_irq=
1478 [ISAPNP] Exclude IRQs for the autoconfiguration
1480 pnp_reserve_dma=
1481 [ISAPNP] Exclude DMAs for the autoconfiguration
1483 pnp_reserve_io= [ISAPNP] Exclude I/O ports for the autoconfiguration
1484 Ranges are in pairs (I/O port base and size).
1486 pnp_reserve_mem=
1487 [ISAPNP] Exclude memory regions for the
1488 autoconfiguration.
1489 Ranges are in pairs (memory base and size).
1491 print-fatal-signals=
1492 [KNL] debug: print fatal signals
1493 print-fatal-signals=1: print segfault info to
1494 the kernel console.
1495 default: off.
1497 printk.time= Show timing data prefixed to each printk message line
1498 Format: <bool> (1/Y/y=enable, 0/N/n=disable)
1500 profile= [KNL] Enable kernel profiling via /proc/profile
1501 Format: [schedule,]<number>
1502 Param: "schedule" - profile schedule points.
1503 Param: <number> - step/bucket size as a power of 2 for
1504 statistical time based profiling.
1505 Param: "sleep" - profile D-state sleeping (millisecs).
1506 Requires CONFIG_SCHEDSTATS
1507 Param: "kvm" - profile VM exits.
1509 processor.max_cstate= [HW,ACPI]
1510 Limit processor to maximum C-state
1511 max_cstate=9 overrides any DMI blacklist limit.
1513 processor.nocst [HW,ACPI]
1514 Ignore the _CST method to determine C-states,
1515 instead using the legacy FADT method
1517 prompt_ramdisk= [RAM] List of RAM disks to prompt for floppy disk
1518 before loading.
1519 See Documentation/ramdisk.txt.
1521 psmouse.proto= [HW,MOUSE] Highest PS2 mouse protocol extension to
1522 probe for; one of (bare|imps|exps|lifebook|any).
1523 psmouse.rate= [HW,MOUSE] Set desired mouse report rate, in reports
1524 per second.
1525 psmouse.resetafter= [HW,MOUSE]
1526 Try to reset the device after so many bad packets
1527 (0 = never).
1528 psmouse.resolution=
1529 [HW,MOUSE] Set desired mouse resolution, in dpi.
1530 psmouse.smartscroll=
1531 [HW,MOUSE] Controls Logitech smartscroll autorepeat.
1532 0 = disabled, 1 = enabled (default).
1534 pss= [HW,OSS] Personal Sound System (ECHO ESC614)
1535 Format:
1536 <io>,<mss_io>,<mss_irq>,<mss_dma>,<mpu_io>,<mpu_irq>
1538 pt. [PARIDE]
1539 See Documentation/paride.txt.
1541 pty.legacy_count=
1542 [KNL] Number of legacy pty's. Overwrites compiled-in
1543 default number.
1545 quiet [KNL] Disable most log messages
1547 r128= [HW,DRM]
1549 raid= [HW,RAID]
1550 See Documentation/md.txt.
1552 ramdisk_blocksize= [RAM]
1553 See Documentation/ramdisk.txt.
1555 ramdisk_size= [RAM] Sizes of RAM disks in kilobytes
1556 See Documentation/ramdisk.txt.
1558 rcu.blimit= [KNL,BOOT] Set maximum number of finished
1559 RCU callbacks to process in one batch.
1561 rcu.qhimark= [KNL,BOOT] Set threshold of queued
1562 RCU callbacks over which batch limiting is disabled.
1564 rcu.qlowmark= [KNL,BOOT] Set threshold of queued
1565 RCU callbacks below which batch limiting is re-enabled.
1567 rdinit= [KNL]
1568 Format: <full_path>
1569 Run specified binary instead of /init from the ramdisk,
1570 used for early userspace startup. See initrd.
1572 reboot= [BUGS=X86-32,BUGS=ARM,BUGS=IA-64] Rebooting mode
1573 Format: <reboot_mode>[,<reboot_mode2>[,...]]
1574 See arch/*/kernel/reboot.c or arch/*/kernel/process.c
1576 reserve= [KNL,BUGS] Force the kernel to ignore some iomem area
1578 reservetop= [X86-32]
1579 Format: nn[KMG]
1580 Reserves a hole at the top of the kernel virtual
1581 address space.
1583 reset_devices [KNL] Force drivers to reset the underlying device
1584 during initialization.
1586 resume= [SWSUSP]
1587 Specify the partition device for software suspend
1589 resume_offset= [SWSUSP]
1590 Specify the offset from the beginning of the partition
1591 given by "resume=" at which the swap header is located,
1592 in <PAGE_SIZE> units (needed only for swap files).
1593 See Documentation/power/swsusp-and-swap-files.txt
1595 retain_initrd [RAM] Keep initrd memory after extraction
1597 rhash_entries= [KNL,NET]
1598 Set number of hash buckets for route cache
1600 riscom8= [HW,SERIAL]
1601 Format: <io_board1>[,<io_board2>[,...<io_boardN>]]
1603 ro [KNL] Mount root device read-only on boot
1605 root= [KNL] Root filesystem
1607 rootdelay= [KNL] Delay (in seconds) to pause before attempting to
1608 mount the root filesystem
1610 rootflags= [KNL] Set root filesystem mount option string
1612 rootfstype= [KNL] Set root filesystem type
1614 rootwait [KNL] Wait (indefinitely) for root device to show up.
1615 Useful for devices that are detected asynchronously
1616 (e.g. USB and MMC devices).
1618 root_plug.vendor_id=
1619 [ROOTPLUG] Override the default vendor ID
1621 root_plug.product_id=
1622 [ROOTPLUG] Override the default product ID
1624 root_plug.debug=
1625 [ROOTPLUG] Enable debugging output
1627 rw [KNL] Mount root device read-write on boot
1629 S [KNL] Run init in single mode
1631 sa1100ir [NET]
1632 See drivers/net/irda/sa1100_ir.c.
1634 sbni= [NET] Granch SBNI12 leased line adapter
1636 sc1200wdt= [HW,WDT] SC1200 WDT (watchdog) driver
1637 Format: <io>[,<timeout>[,<isapnp>]]
1639 scsi_debug_*= [SCSI]
1640 See drivers/scsi/scsi_debug.c.
1642 scsi_default_dev_flags=
1643 [SCSI] SCSI default device flags
1644 Format: <integer>
1646 scsi_dev_flags= [SCSI] Black/white list entry for vendor and model
1647 Format: <vendor>:<model>:<flags>
1648 (flags are integer value)
1650 scsi_logging_level= [SCSI] a bit mask of logging levels
1651 See drivers/scsi/scsi_logging.h for bits. Also
1652 settable via sysctl at dev.scsi.logging_level
1653 (/proc/sys/dev/scsi/logging_level).
1654 There is also a nice 'scsi_logging_level' script in the
1655 S390-tools package, available for download at
1656 http://www-128.ibm.com/developerworks/linux/linux390/s390-tools-1.5.4.html
1658 scsi_mod.scan= [SCSI] sync (default) scans SCSI busses as they are
1659 discovered. async scans them in kernel threads,
1660 allowing boot to proceed. none ignores them, expecting
1661 user space to do the scan.
1663 selinux [SELINUX] Disable or enable SELinux at boot time.
1664 Format: { "0" | "1" }
1665 See security/selinux/Kconfig help text.
1666 0 -- disable.
1667 1 -- enable.
1668 Default value is set via kernel config option.
1669 If enabled at boot time, /selinux/disable can be used
1670 later to disable prior to initial policy load.
1672 selinux_compat_net =
1673 [SELINUX] Set initial selinux_compat_net flag value.
1674 Format: { "0" | "1" }
1675 0 -- use new secmark-based packet controls
1676 1 -- use legacy packet controls
1677 Default value is 0 (preferred).
1678 Value can be changed at runtime via
1679 /selinux/compat_net.
1681 serialnumber [BUGS=X86-32]
1683 shapers= [NET]
1684 Maximal number of shapers.
1686 sim710= [SCSI,HW]
1687 See header of drivers/scsi/sim710.c.
1689 simeth= [IA-64]
1690 simscsi=
1692 slram= [HW,MTD]
1694 slub_debug[=options[,slabs]] [MM, SLUB]
1695 Enabling slub_debug allows one to determine the
1696 culprit if slab objects become corrupted. Enabling
1697 slub_debug can create guard zones around objects and
1698 may poison objects when not in use. Also tracks the
1699 last alloc / free. For more information see
1700 Documentation/vm/slub.txt.
1702 slub_max_order= [MM, SLUB]
1703 Determines the maximum allowed order for slabs.
1704 A high setting may cause OOMs due to memory
1705 fragmentation. For more information see
1706 Documentation/vm/slub.txt.
1708 slub_min_objects= [MM, SLUB]
1709 The minimum number of objects per slab. SLUB will
1710 increase the slab order up to slub_max_order to
1711 generate a sufficiently large slab able to contain
1712 the number of objects indicated. The higher the number
1713 of objects the smaller the overhead of tracking slabs
1714 and the less frequently locks need to be acquired.
1715 For more information see Documentation/vm/slub.txt.
1717 slub_min_order= [MM, SLUB]
1718 Determines the mininum page order for slabs. Must be
1719 lower than slub_max_order.
1720 For more information see Documentation/vm/slub.txt.
1722 slub_nomerge [MM, SLUB]
1723 Disable merging of slabs with similar size. May be
1724 necessary if there is some reason to distinguish
1725 allocs to different slabs. Debug options disable
1726 merging on their own.
1727 For more information see Documentation/vm/slub.txt.
1729 smart2= [HW]
1730 Format: <io1>[,<io2>[,...,<io8>]]
1732 smp-alt-once [X86-32,SMP] On a hotplug CPU system, only
1733 attempt to substitute SMP alternatives once at boot.
1735 smsc-ircc2.nopnp [HW] Don't use PNP to discover SMC devices
1736 smsc-ircc2.ircc_cfg= [HW] Device configuration I/O port
1737 smsc-ircc2.ircc_sir= [HW] SIR base I/O port
1738 smsc-ircc2.ircc_fir= [HW] FIR base I/O port
1739 smsc-ircc2.ircc_irq= [HW] IRQ line
1740 smsc-ircc2.ircc_dma= [HW] DMA channel
1741 smsc-ircc2.ircc_transceiver= [HW] Transceiver type:
1742 0: Toshiba Satellite 1800 (GP data pin select)
1743 1: Fast pin select (default)
1744 2: ATC IRMode
1746 snd-ad1816a= [HW,ALSA]
1748 snd-ad1848= [HW,ALSA]
1750 snd-ali5451= [HW,ALSA]
1752 snd-als100= [HW,ALSA]
1754 snd-als4000= [HW,ALSA]
1756 snd-azt2320= [HW,ALSA]
1758 snd-cmi8330= [HW,ALSA]
1760 snd-cmipci= [HW,ALSA]
1762 snd-cs4231= [HW,ALSA]
1764 snd-cs4232= [HW,ALSA]
1766 snd-cs4236= [HW,ALSA]
1768 snd-cs4281= [HW,ALSA]
1770 snd-cs46xx= [HW,ALSA]
1772 snd-dt019x= [HW,ALSA]
1774 snd-dummy= [HW,ALSA]
1776 snd-emu10k1= [HW,ALSA]
1778 snd-ens1370= [HW,ALSA]
1780 snd-ens1371= [HW,ALSA]
1782 snd-es968= [HW,ALSA]
1784 snd-es1688= [HW,ALSA]
1786 snd-es18xx= [HW,ALSA]
1788 snd-es1938= [HW,ALSA]
1790 snd-es1968= [HW,ALSA]
1792 snd-fm801= [HW,ALSA]
1794 snd-gusclassic= [HW,ALSA]
1796 snd-gusextreme= [HW,ALSA]
1798 snd-gusmax= [HW,ALSA]
1800 snd-hdsp= [HW,ALSA]
1802 snd-ice1712= [HW,ALSA]
1804 snd-intel8x0= [HW,ALSA]
1806 snd-interwave= [HW,ALSA]
1808 snd-interwave-stb=
1809 [HW,ALSA]
1811 snd-korg1212= [HW,ALSA]
1813 snd-maestro3= [HW,ALSA]
1815 snd-mpu401= [HW,ALSA]
1817 snd-mtpav= [HW,ALSA]
1819 snd-nm256= [HW,ALSA]
1821 snd-opl3sa2= [HW,ALSA]
1823 snd-opti92x-ad1848=
1824 [HW,ALSA]
1826 snd-opti92x-cs4231=
1827 [HW,ALSA]
1829 snd-opti93x= [HW,ALSA]
1831 snd-pmac= [HW,ALSA]
1833 snd-rme32= [HW,ALSA]
1835 snd-rme96= [HW,ALSA]
1837 snd-rme9652= [HW,ALSA]
1839 snd-sb8= [HW,ALSA]
1841 snd-sb16= [HW,ALSA]
1843 snd-sbawe= [HW,ALSA]
1845 snd-serial= [HW,ALSA]
1847 snd-sgalaxy= [HW,ALSA]
1849 snd-sonicvibes= [HW,ALSA]
1851 snd-sun-amd7930=
1852 [HW,ALSA]
1854 snd-sun-cs4231= [HW,ALSA]
1856 snd-trident= [HW,ALSA]
1858 snd-usb-audio= [HW,ALSA,USB]
1860 snd-via82xx= [HW,ALSA]
1862 snd-virmidi= [HW,ALSA]
1864 snd-wavefront= [HW,ALSA]
1866 snd-ymfpci= [HW,ALSA]
1868 sonypi.*= [HW] Sony Programmable I/O Control Device driver
1869 See Documentation/sonypi.txt
1871 specialix= [HW,SERIAL] Specialix multi-serial port adapter
1872 See Documentation/specialix.txt.
1874 spia_io_base= [HW,MTD]
1875 spia_fio_base=
1876 spia_pedr=
1877 spia_peddr=
1879 sscape= [HW,OSS]
1880 Format: <io>,<irq>,<dma>,<mpu_io>,<mpu_irq>
1882 st= [HW,SCSI] SCSI tape parameters (buffers, etc.)
1883 See Documentation/scsi/st.txt.
1885 st0x= [HW,SCSI]
1886 See header of drivers/scsi/seagate.c.
1888 sti= [PARISC,HW]
1889 Format: <num>
1890 Set the STI (builtin display/keyboard on the HP-PARISC
1891 machines) console (graphic card) which should be used
1892 as the initial boot-console.
1893 See also comment in drivers/video/console/sticore.c.
1895 sti_font= [HW]
1896 See comment in drivers/video/console/sticore.c.
1898 stifb= [HW]
1899 Format: bpp:<bpp1>[:<bpp2>[:<bpp3>...]]
1901 sunrpc.pool_mode=
1902 [NFS]
1903 Control how the NFS server code allocates CPUs to
1904 service thread pools. Depending on how many NICs
1905 you have and where their interrupts are bound, this
1906 option will affect which CPUs will do NFS serving.
1907 Note: this parameter cannot be changed while the
1908 NFS server is running.
1910 auto the server chooses an appropriate mode
1911 automatically using heuristics
1912 global a single global pool contains all CPUs
1913 percpu one pool for each CPU
1914 pernode one pool for each NUMA node (equivalent
1915 to global on non-NUMA machines)
1917 swiotlb= [IA-64] Number of I/O TLB slabs
1919 switches= [HW,M68k]
1921 sym53c416= [HW,SCSI]
1922 See header of drivers/scsi/sym53c416.c.
1924 sysrq_always_enabled
1925 [KNL]
1926 Ignore sysrq setting - this boot parameter will
1927 neutralize any effect of /proc/sys/kernel/sysrq.
1928 Useful for debugging.
1930 t128= [HW,SCSI]
1931 See header of drivers/scsi/t128.c.
1933 tdfx= [HW,DRM]
1935 thash_entries= [KNL,NET]
1936 Set number of hash buckets for TCP connection
1938 thermal.act= [HW,ACPI]
1939 -1: disable all active trip points in all thermal zones
1940 <degrees C>: override all lowest active trip points
1942 thermal.crt= [HW,ACPI]
1943 -1: disable all critical trip points in all thermal zones
1944 <degrees C>: lower all critical trip points
1946 thermal.nocrt= [HW,ACPI]
1947 Set to disable actions on ACPI thermal zone
1948 critical and hot trip points.
1950 thermal.off= [HW,ACPI]
1951 1: disable ACPI thermal control
1953 thermal.psv= [HW,ACPI]
1954 -1: disable all passive trip points
1955 <degrees C>: override all passive trip points to this value
1957 thermal.tzp= [HW,ACPI]
1958 Specify global default ACPI thermal zone polling rate
1959 <deci-seconds>: poll all this frequency
1960 0: no polling (default)
1962 time Show timing data prefixed to each printk message line
1963 [deprecated, see 'printk.time']
1965 tipar.timeout= [HW,PPT]
1966 Set communications timeout in tenths of a second
1967 (default 15).
1969 tipar.delay= [HW,PPT]
1970 Set inter-bit delay in microseconds (default 10).
1972 tmc8xx= [HW,SCSI]
1973 See header of drivers/scsi/seagate.c.
1975 tmscsim= [HW,SCSI]
1976 See comment before function dc390_setup() in
1977 drivers/scsi/tmscsim.c.
1979 tp720= [HW,PS2]
1981 trix= [HW,OSS] MediaTrix AudioTrix Pro
1982 Format:
1983 <io>,<irq>,<dma>,<dma2>,<sb_io>,<sb_irq>,<sb_dma>,<mpu_io>,<mpu_irq>
1985 turbografx.map[2|3]= [HW,JOY]
1986 TurboGraFX parallel port interface
1987 Format:
1988 <port#>,<js1>,<js2>,<js3>,<js4>,<js5>,<js6>,<js7>
1989 See also Documentation/input/joystick-parport.txt
1991 u14-34f= [HW,SCSI] UltraStor 14F/34F SCSI host adapter
1992 See header of drivers/scsi/u14-34f.c.
1994 uart401= [HW,OSS]
1995 Format: <io>,<irq>
1997 uart6850= [HW,OSS]
1998 Format: <io>,<irq>
2000 uhci-hcd.ignore_oc=
2001 [USB] Ignore overcurrent events (default N).
2002 Some badly-designed motherboards generate lots of
2003 bogus events, for ports that aren't wired to
2004 anything. Set this parameter to avoid log spamming.
2005 Note that genuine overcurrent events won't be
2006 reported either.
2008 usbcore.autosuspend=
2009 [USB] The autosuspend time delay (in seconds) used
2010 for newly-detected USB devices (default 2). This
2011 is the time required before an idle device will be
2012 autosuspended. Devices for which the delay is set
2013 to a negative value won't be autosuspended at all.
2015 usbhid.mousepoll=
2016 [USBHID] The interval which mice are to be polled at.
2018 vdso= [X86-32,SH,x86-64]
2019 vdso=2: enable compat VDSO (default with COMPAT_VDSO)
2020 vdso=1: enable VDSO (default)
2021 vdso=0: disable VDSO mapping
2023 vdso32= [X86-32,X86-64]
2024 vdso32=2: enable compat VDSO (default with COMPAT_VDSO)
2025 vdso32=1: enable 32-bit VDSO (default)
2026 vdso32=0: disable 32-bit VDSO mapping
2028 vector= [IA-64,SMP]
2029 vector=percpu: enable percpu vector domain
2031 video= [FB] Frame buffer configuration
2032 See Documentation/fb/modedb.txt.
2034 vga= [BOOT,X86-32] Select a particular video mode
2035 See Documentation/i386/boot.txt and
2036 Documentation/svga.txt.
2037 Use vga=ask for menu.
2038 This is actually a boot loader parameter; the value is
2039 passed to the kernel using a special protocol.
2041 vmalloc=nn[KMG] [KNL,BOOT] Forces the vmalloc area to have an exact
2042 size of <nn>. This can be used to increase the
2043 minimum size (128MB on x86). It can also be used to
2044 decrease the size and leave more room for directly
2045 mapped kernel RAM.
2047 vmhalt= [KNL,S390] Perform z/VM CP command after system halt.
2048 Format: <command>
2050 vmpanic= [KNL,S390] Perform z/VM CP command after kernel panic.
2051 Format: <command>
2053 vmpoff= [KNL,S390] Perform z/VM CP command after power off.
2054 Format: <command>
2056 waveartist= [HW,OSS]
2057 Format: <io>,<irq>,<dma>,<dma2>
2059 wd33c93= [HW,SCSI]
2060 See header of drivers/scsi/wd33c93.c.
2062 wd7000= [HW,SCSI]
2063 See header of drivers/scsi/wd7000.c.
2065 wdt= [WDT] Watchdog
2066 See Documentation/watchdog/wdt.txt.
2068 xd= [HW,XT] Original XT pre-IDE (RLL encoded) disks.
2069 xd_geo= See header of drivers/block/xd.c.
2071 xirc2ps_cs= [NET,PCMCIA]
2072 Format:
2073 <irq>,<irq_mask>,<io>,<full_duplex>,<do_sound>,<lockup_hack>[,<irq2>[,<irq3>[,<irq4>]]]
2075 norandmaps Don't use address space randomization
2076 Equivalent to echo 0 > /proc/sys/kernel/randomize_va_space
2078 ______________________________________________________________________
2080 TODO:
2082 Add documentation for ALSA options.
2083 Add more DRM drivers.