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
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/power/pm.txt, pci=noacpi
143 acpi_apic_instance= [ACPI, IOAPIC]
145 2: use 2nd APIC table, if available
146 1,0: use 1st APIC table
149 acpi_sleep= [HW,ACPI] Sleep options
150 Format: { s3_bios, s3_mode, s3_beep, old_ordering }
151 See Documentation/power/video.txt for s3_bios and s3_mode.
152 s3_beep is for debugging; it makes the PC's speaker beep
153 as soon as the kernel's real-mode entry point is called.
154 old_ordering causes the ACPI 1.0 ordering of the _PTS
155 control method, wrt putting devices into low power
156 states, to be enforced (the ACPI 2.0 ordering of _PTS is
159 acpi_sci= [HW,ACPI] ACPI System Control Interrupt trigger mode
160 Format: { level | edge | high | low }
162 acpi_irq_balance [HW,ACPI]
163 ACPI will balance active IRQs
166 acpi_irq_nobalance [HW,ACPI]
167 ACPI will not move active IRQs (default)
170 acpi_irq_pci= [HW,ACPI] If irq_balance, clear listed IRQs for
172 Format: <irq>,<irq>...
174 acpi_irq_isa= [HW,ACPI] If irq_balance, mark listed IRQs used by ISA
175 Format: <irq>,<irq>...
177 acpi_no_auto_ssdt [HW,ACPI] Disable automatic loading of SSDT
179 acpi_os_name= [HW,ACPI] Tell ACPI BIOS the name of the OS
180 Format: To spoof as Windows 98: ="Microsoft Windows"
182 acpi_osi= [HW,ACPI] Modify list of supported OS interface strings
183 acpi_osi="string1" # add string1 -- only one string
184 acpi_osi="!string2" # remove built-in string2
185 acpi_osi= # disable all strings
187 acpi_serialize [HW,ACPI] force serialization of AML methods
189 acpi_skip_timer_override [HW,ACPI]
190 Recognize and ignore IRQ0/pin2 Interrupt Override.
191 For broken nForce2 BIOS resulting in XT-PIC timer.
192 acpi_use_timer_override [HW,ACPI}
193 Use timer override. For some broken Nvidia NF5 boards
194 that require a timer override, but don't have
197 acpi.debug_layer= [HW,ACPI]
199 Each bit of the <int> indicates an ACPI debug layer,
200 1: enable, 0: disable. It is useful for boot time
201 debugging. After system has booted up, it can be set
202 via /sys/module/acpi/parameters/debug_layer.
203 CONFIG_ACPI_DEBUG must be enabled for this to produce any output.
204 Available bits (add the numbers together) to enable debug output
205 for specific parts of the ACPI subsystem:
206 0x01 utilities 0x02 hardware 0x04 events 0x08 tables
207 0x10 namespace 0x20 parser 0x40 dispatcher
208 0x80 executer 0x100 resources 0x200 acpica debugger
209 0x400 os services 0x800 acpica disassembler.
210 The number can be in decimal or prefixed with 0x in hex.
211 Warning: Many of these options can produce a lot of
212 output and make your system unusable. Be very careful.
214 acpi.debug_level= [HW,ACPI]
216 Each bit of the <int> indicates an ACPI debug level,
217 1: enable, 0: disable. It is useful for boot time
218 debugging. After system has booted up, it can be set
219 via /sys/module/acpi/parameters/debug_level.
220 CONFIG_ACPI_DEBUG must be enabled for this to produce any output.
221 Available bits (add the numbers together) to enable different
222 debug output levels of the ACPI subsystem:
223 0x01 error 0x02 warn 0x04 init 0x08 debug object
224 0x10 info 0x20 init names 0x40 parse 0x80 load
225 0x100 dispatch 0x200 execute 0x400 names 0x800 operation region
226 0x1000 bfield 0x2000 tables 0x4000 values 0x8000 objects
227 0x10000 resources 0x20000 user requests 0x40000 package.
228 The number can be in decimal or prefixed with 0x in hex.
229 Warning: Many of these options can produce a lot of
230 output and make your system unusable. Be very careful.
232 acpi_pm_good [X86-32,X86-64]
233 Override the pmtimer bug detection: force the kernel
234 to assume that this machine's pmtimer latches its value
235 and always returns good values.
238 { off | try_unsupported }
239 off: disable AGP support
240 try_unsupported: try to drive unsupported chipsets
241 (may crash computer or cause data corruption)
243 enable_timer_pin_1 [i386,x86-64]
244 Enable PIN 1 of APIC timer
245 Can be useful to work around chipset bugs
246 (in particular on some ATI chipsets).
247 The kernel tries to set a reasonable default.
249 disable_timer_pin_1 [i386,x86-64]
250 Disable PIN 1 of APIC timer
251 Can be useful to work around chipset bugs.
254 Format: <io>,<irq>,<dma>,<dma2>,<type>
257 See header of drivers/scsi/advansys.c.
259 advwdt= [HW,WDT] Advantech WDT
260 Format: <iostart>,<iostop>
262 aedsp16= [HW,OSS] Audio Excel DSP 16
263 Format: <io>,<irq>,<dma>,<mss_io>,<mpu_io>,<mpu_irq>
264 See also header of sound/oss/aedsp16.c.
267 See Documentation/scsi/aha152x.txt.
270 Format: <portbase>[,<buson>,<busoff>[,<dmaspeed>]]
273 See Documentation/scsi/aic7xxx.txt.
276 See Documentation/scsi/aic79xx.txt.
278 amd_iommu= [HW,X86-84]
279 Pass parameters to the AMD IOMMU driver in the system.
281 isolate - enable device isolation (each device, as far
282 as possible, will get its own protection
284 amd_iommu_size= [HW,X86-64]
285 Define the size of the aperture for the AMD IOMMU
286 driver. Possible values are:
287 '32M', '64M' (default), '128M', '256M', '512M', '1G'
289 amijoy.map= [HW,JOY] Amiga joystick support
290 Map of devices attached to JOY0DAT and JOY1DAT
292 See also Documentation/kernel/input/joystick.txt
294 analog.map= [HW,JOY] Analog joystick and gamepad support
295 Specifies type or capabilities of an analog joystick
296 connected to one of 16 gameports
297 Format: <type1>,<type2>,..<type16>
300 Power management functions (SPARCstation-4/5 + deriv.)
302 Disable APC CPU standby support. SPARCstation-Fox does
303 not play well with APC CPU idle - disable it if you have
304 APC and your system crashes randomly.
306 apic= [APIC,i386] Advanced Programmable Interrupt Controller
307 Change the output verbosity whilst booting
308 Format: { quiet (default) | verbose | debug }
309 Change the amount of debugging information output
310 when initialising the APIC and IO-APIC components.
312 apm= [APM] Advanced Power Management
313 See header of arch/x86/kernel/apm_32.c.
315 arcrimi= [HW,NET] ARCnet - "RIM I" (entirely mem-mapped) cards
316 Format: <io>,<irq>,<nodeID>
320 atarimouse= [HW,MOUSE] Atari Mouse
322 atascsi= [HW,SCSI] Atari SCSI
324 atkbd.extra= [HW] Enable extra LEDs and keys on IBM RapidAccess,
325 EzKey and similar keyboards
327 atkbd.reset= [HW] Reset keyboard during initialization
329 atkbd.set= [HW] Select keyboard code set
330 Format: <int> (2 = AT (default), 3 = PS/2)
332 atkbd.scroll= [HW] Enable scroll wheel on MS Office and similar
335 atkbd.softraw= [HW] Choose between synthetic and real raw mode
336 Format: <bool> (0 = real, 1 = synthetic (default))
338 atkbd.softrepeat= [HW]
339 Use software keyboard repeat
343 baycom_epp= [HW,AX25]
346 baycom_par= [HW,AX25] BayCom Parallel Port AX.25 Modem
348 See header of drivers/net/hamradio/baycom_par.c.
350 baycom_ser_fdx= [HW,AX25]
351 BayCom Serial Port AX.25 Modem (Full Duplex Mode)
352 Format: <io>,<irq>,<mode>[,<baud>]
353 See header of drivers/net/hamradio/baycom_ser_fdx.c.
355 baycom_ser_hdx= [HW,AX25]
356 BayCom Serial Port AX.25 Modem (Half Duplex Mode)
357 Format: <io>,<irq>,<mode>
358 See header of drivers/net/hamradio/baycom_ser_hdx.c.
360 boot_delay= Milliseconds to delay each printk during boot.
361 Values larger than 10 seconds (10000) are changed to
365 bttv.card= [HW,V4L] bttv (bt848 + bt878 based grabber cards)
366 bttv.radio= Most important insmod options are available as
368 bttv.pll= See Documentation/video4linux/bttv/Insmod-options
369 bttv.tuner= and Documentation/video4linux/bttv/CARDLIST
372 See drivers/scsi/BusLogic.c, comment before function
373 BusLogic_ParseDriverOptions().
375 c101= [NET] Moxa C101 synchronous serial card
377 cachesize= [BUGS=X86-32] Override level 2 CPU cache size detection.
378 Sometimes CPU hardware bugs make them report the cache
379 size incorrectly. The kernel will attempt work arounds
380 to fix known problems, but for some CPUs it is not
381 possible to determine what the correct size should be.
382 This option provides an override for these situations.
384 security= [SECURITY] Choose a security module to enable at boot.
385 If this boot parameter is not specified, only the first
386 security module asking for security registration will be
387 loaded. An invalid security module name will be treated
388 as if no module has been chosen.
391 [SECURITY] Disable capabilities. This would normally
392 be used only if an alternative security model is to be
393 configured. Potentially dangerous and should only be
394 used if you are entirely sure of the consequences.
396 ccw_timeout_log [S390]
397 See Documentation/s390/CommonIO for details.
399 cgroup_disable= [KNL] Disable a particular controller
400 Format: {name of the controller(s) to disable}
401 {Currently supported controllers - "memory"}
403 checkreqprot [SELINUX] Set initial checkreqprot flag value.
404 Format: { "0" | "1" }
405 See security/selinux/Kconfig help text.
406 0 -- check protection applied by kernel (includes
407 any implied execute protection).
408 1 -- check protection requested by application.
409 Default value is set via a kernel config option.
410 Value can be changed at runtime via
411 /selinux/checkreqprot.
414 See Documentation/s390/CommonIO for details.
416 clock= [BUGS=X86-32, HW] gettimeofday clocksource override.
418 Forces specified clocksource (if available) to be used
419 when calculating gettimeofday(). If specified
420 clocksource is not available, it defaults to PIT.
421 Format: { pit | tsc | cyclone | pmtmr }
423 clocksource= [GENERIC_TIME] Override the default clocksource
425 Override the default clocksource and use the clocksource
426 with the name specified.
427 Some clocksource names to choose from, depending on
429 [all] jiffies (this is the base, fallback clocksource)
431 [ARM] imx_timer1,OSTS,netx_timer,mpu_timer2,
432 pxa_timer,timer3,32k_counter,timer0_1
434 [X86-32] pit,hpet,tsc,vmi-timer;
435 scx200_hrt on Geode; cyclone on IBM x440
443 clearcpuid=BITNUM [X86]
444 Disable CPUID feature X for the kernel. See
445 include/asm-x86/cpufeature.h for the valid bit numbers.
446 Note the Linux specific bits are not necessarily
447 stable over kernel options, but the vendor specific
449 Also note that user programs calling CPUID directly
450 or using the feature without checking anything
451 will still see it. This just prevents it from
452 being used by the kernel or shown in /proc/cpuinfo.
453 Also note the kernel might malfunction if you disable
456 code_bytes [IA32/X86_64] How many bytes of object code to print
463 [IA32/X86_64] Disable/Enable interrupt 0 timer routing
464 over the 8254 in addition to over the IO-APIC. The
465 kernel tries to set a sensible default.
467 hpet= [X86-32,HPET] option to control HPET usage
468 Format: { enable (default) | disable | force }
469 disable: disable HPET and use PIT instead
470 force: allow force enabled of undocumented chips (ICH4,
473 com20020= [HW,NET] ARCnet - COM20020 chipset
475 <io>[,<irq>[,<nodeID>[,<backplane>[,<ckp>[,<timeout>]]]]]
477 com90io= [HW,NET] ARCnet - COM90xx chipset (IO-mapped buffers)
481 ARCnet - COM90xx chipset (memory-mapped buffers)
482 Format: <io>[,<irq>[,<memstart>]]
484 condev= [HW,S390] console device
487 console= [KNL] Output console device and options.
489 tty<n> Use the virtual console device <n>.
493 Use the specified serial port. The options are of
494 the form "bbbbpnf", where "bbbb" is the baud rate,
495 "p" is parity ("n", "o", or "e"), "n" is number of
496 bits, and "f" is flow control ("r" for RTS or
497 omit it). Default is "9600n8".
499 See Documentation/serial-console.txt for more
501 Documentation/networking/netconsole.txt for an
504 uart[8250],io,<addr>[,options]
505 uart[8250],mmio,<addr>[,options]
506 Start an early, polled-mode console on the 8250/16550
507 UART at the specified I/O port or MMIO address,
508 switching to the matching ttyS device later. The
509 options are the same as for ttyS, above.
511 If the device connected to the port is not a TTY but a braille
512 device, prepend "brl," before the device type, for instance
514 For now, only VisioBraille is supported.
516 earlycon= [KNL] Output early console device and options.
517 uart[8250],io,<addr>[,options]
518 uart[8250],mmio,<addr>[,options]
519 Start an early, polled-mode console on the 8250/16550
520 UART at the specified I/O port or MMIO address.
521 The options are the same as for ttyS, above.
524 [HW] Never suspend the console
525 Disable suspending of consoles during suspend and
526 hibernate operations. Once disabled, debugging
527 messages can reach various consoles while the rest
528 of the system is being put to sleep (ie, while
529 debugging driver suspend/resume hooks). This may
530 not work reliably with all consoles, but is known
531 to work with serial and VGA consoles.
533 cpcihp_generic= [HW,PCI] Generic port I/O CompactPCI driver
535 <first_slot>,<last_slot>,<port>,<enum_bit>[,<debug>]
537 crashkernel=nn[KMG]@ss[KMG]
538 [KNL] Reserve a chunk of physical memory to
539 hold a kernel to switch to with kexec on panic.
541 crashkernel=range1:size1[,range2:size2,...][@offset]
542 [KNL] Same as above, but depends on the memory
543 in the running system. The syntax of range is
544 start-[end] where start and end are both
545 a memory unit (amount[KMG]). See also
546 Documentation/kdump/kdump.txt for a example.
549 Format: <io>,<irq>,<dma>,<dma2>,<mpuio>,<mpuirq>
554 cs89x0_media= [HW,NET]
555 Format: { rj45 | aui | bnc }
558 See header of drivers/s390/block/dasd_devmap.c.
560 db9.dev[2|3]= [HW,JOY] Multisystem joystick support via parallel port
561 (one device per port)
562 Format: <port#>,<type>
563 See also Documentation/input/joystick-parport.txt
565 debug [KNL] Enable kernel debugging (events log level).
568 [KNL] verbose self-tests
570 Print debugging info while doing the locking API
572 We default to 0 (no extra messages), setting it to
573 1 will print _a lot_ more information - normally
574 only useful to kernel developers.
576 debug_objects [KNL] Enable object debugging
578 debugpat [X86] Enable PAT debugging
580 decnet.addr= [HW,NET]
581 Format: <area>[,<node>]
582 See also Documentation/networking/decnet.txt.
585 Format: <blue0>,<blue1>,<blue2>,...,<blue15>
586 Change the default blue palette of the console.
587 This is a 16-member array composed of values
591 Format: <green0>,<green1>,<green2>,...,<green15>
592 Change the default green palette of the console.
593 This is a 16-member array composed of values
597 Format: <red0>,<red1>,<red2>,...,<red15>
598 Change the default red palette of the console.
599 This is a 16-member array composed of values
605 Set system-wide default UTF-8 mode for all tty's.
606 Default is 1, i.e. UTF-8 mode is enabled for all
607 newly opened terminals.
610 Set number of hash buckets for dentry cache.
613 IO parameters + enable/disable command.
615 digiepca= [HW,SERIAL]
616 See drivers/char/README.epca and
617 Documentation/digiepca.txt.
619 disable_mtrr_cleanup [X86]
620 enable_mtrr_cleanup [X86]
621 The kernel tries to adjust MTRR layout from continuous
622 to discrete, to make X server driver able to add WB
623 entry later. This parameter enables/disables that.
625 mtrr_chunk_size=nn[KMG] [X86]
626 used for mtrr cleanup. It is largest continous chunk
627 that could hold holes aka. UC entries.
629 mtrr_gran_size=nn[KMG] [X86]
630 Used for mtrr cleanup. It is granularity of mtrr block.
632 Large value could prevent small alignment from
635 mtrr_spare_reg_nr=n [X86]
637 Range: 0,7 : spare reg number
639 Used for mtrr cleanup. It is spare mtrr entries number.
640 Set to 2 or more if your graphical card needs more.
642 disable_mtrr_trim [X86, Intel and AMD only]
643 By default the kernel will trim any uncacheable
644 memory out of your available memory pool based on
645 MTRR settings. This parameter disables that behavior,
646 possibly causing your machine to run very slowly.
648 dmasound= [HW,OSS] Sound subsystem buffers
654 earlyprintk= [X86-32,X86-64,SH,BLACKFIN]
656 earlyprintk=serial[,ttySn[,baudrate]]
658 Append ",keep" to not disable it when the real console
661 Only vga or serial at a time, not both.
663 Currently only ttyS0 and ttyS1 are supported.
665 Interaction with the standard serial driver is not
668 The VGA output is eventually overwritten by the real
674 Format: {"off" | "on" | "skip[mbr]"}
676 eisa_irq_edge= [PARISC,HW]
677 See header of drivers/parisc/eisa.c.
680 See comment before function elanfreq_setup() in
681 arch/x86/kernel/cpu/cpufreq/elanfreq.c.
684 Format: {"anticipatory" | "cfq" | "deadline" | "noop"}
685 See Documentation/block/as-iosched.txt and
686 Documentation/block/deadline-iosched.txt for details.
688 elfcorehdr= [X86-32, X86_64]
689 Specifies physical address of start of kernel core
690 image elf header. Generally kexec loader will
691 pass this option to capture kernel.
692 See Documentation/kdump/kdump.txt for details.
694 enforcing [SELINUX] Set initial enforcing status.
696 See security/selinux/Kconfig help text.
697 0 -- permissive (log only, no denials).
698 1 -- enforcing (deny and log).
700 Value can be changed at runtime via /selinux/enforce.
703 Format: <spdif>,[<nomix>,[<amplifier>]]
704 See also header of sound/oss/es1371.c.
706 ether= [HW,NET] Ethernet cards parameters
707 This option is obsoleted by the "netdev=" option, which
708 has equivalent usage. See its documentation for details.
710 eurwdt= [HW,WDT] Eurotech CPU-1220/1410 onboard watchdog.
715 fail_make_request=[KNL]
716 General fault injection mechanism.
717 Format: <interval>,<probability>,<space>,<times>
718 See also /Documentation/fault-injection/.
721 See header of drivers/scsi/fd_mcs.c.
724 See header of drivers/scsi/fdomain.c.
727 See Documentation/floppy.txt.
729 force_pal_cache_flush
730 [IA-64] Avoid check_sal_cache_flush which may hang on
731 buggy SAL_CACHE_FLUSH implementations. Using this
732 parameter will force ia64_sal_cache_flush to call
733 ia64_pal_cache_flush instead of SAL_CACHE_FLUSH.
736 [HW,JOY] Multisystem joystick and NES/SNES/PSX pad
737 support via parallel port (up to 5 devices per port)
738 Format: <port#>,<pad1>,<pad2>,<pad3>,<pad4>,<pad5>
739 See also Documentation/input/joystick-parport.txt
743 gart_fix_e820= [X86_64] disable the fix e820 for K8 GART
748 See header of drivers/scsi/gdth.c.
750 gpt [EFI] Forces disk with valid GPT signature but
751 invalid Protective MBR to be treated as GPT.
755 hashdist= [KNL,NUMA] Large hashes allocated during boot
756 are distributed across NUMA nodes. Defaults on
757 for IA-64, off otherwise.
758 Format: 0 | 1 (for off | on)
760 hcl= [IA-64] SGI's Hardware Graph compatibility layer
762 hd= [EIDE] (E)IDE hard drive subsystem geometry
763 Format: <cyl>,<head>,<sect>
765 highmem=nn[KMG] [KNL,BOOT] forces the highmem zone to have an exact
766 size of <nn>. This works even on boxes that have no
767 highmem otherwise. This also works to reduce highmem
768 size on bigger boxes.
770 highres= [KNL] Enable/disable high resolution timer mode.
771 Valid parameters: "on", "off"
775 See Documentation/isdn/README.HiSax.
777 hugepages= [HW,X86-32,IA-64] Maximal number of HugeTLB pages.
778 hugepagesz= [HW,IA-64,PPC] The size of the HugeTLB pages.
780 i8042.direct [HW] Put keyboard port into non-translated mode
781 i8042.dumbkbd [HW] Pretend that controller can only read data from
782 keyboard and cannot control its state
783 (Don't attempt to blink the leds)
784 i8042.noaux [HW] Don't check for auxiliary (== mouse) port
785 i8042.nokbd [HW] Don't check/create keyboard port
786 i8042.noloop [HW] Disable the AUX Loopback command while probing
788 i8042.nomux [HW] Don't check presence of an active multiplexing
790 i8042.nopnp [HW] Don't use ACPIPnP / PnPBIOS to discover KBD/AUX
793 [HW] Frequency with which keyboard LEDs should blink
794 when kernel panics (default is 0.5 sec)
795 i8042.reset [HW] Reset the controller during init and cleanup
796 i8042.unlock [HW] Unlock (ignore) the keylock
800 i8k.ignore_dmi [HW] Continue probing hardware even if DMI data
801 indicates that the driver is running on unsupported
803 i8k.force [HW] Activate i8k driver even if SMM BIOS signature
804 does not match list of supported models.
806 [HW] Report power status in /proc/i8k
807 (disabled by default)
808 i8k.restricted [HW] Allow controlling fans only if SYS_ADMIN
811 ibmmcascsi= [HW,MCA,SCSI] IBM MicroChannel SCSI adapter
812 See Documentation/mca.txt.
815 Format: <io>[,<membase>[,<icn_id>[,<icn_id2>]]]
817 ide= [HW] (E)IDE subsystem
818 Format: ide=nodma or ide=doubler
819 See Documentation/ide/ide.txt.
821 idebus= [HW] (E)IDE subsystem - VLB/PCI bus speed
822 See Documentation/ide/ide.txt.
825 Format: idle=poll or idle=mwait, idle=halt, idle=nomwait
826 Poll forces a polling idle loop that can slightly improves the performance
827 of waking up a idle CPU, but will use a lot of power and make the system
828 run hot. Not recommended.
829 idle=mwait. On systems which support MONITOR/MWAIT but the kernel chose
830 to not use it because it doesn't save as much power as a normal idle
831 loop use the MONITOR/MWAIT idle loop anyways. Performance should be the same
833 idle=halt. Halt is forced to be used for CPU idle.
834 In such case C2/C3 won't be used again.
835 idle=nomwait. Disable mwait for CPU C-states
837 ide-pci-generic.all-generic-ide [HW] (E)IDE subsystem
838 Claim all unknown PCI IDE storage controllers.
840 ignore_loglevel [KNL]
841 Ignore loglevel setting - this will print /all/
842 kernel messages to the console. Useful for debugging.
845 Set number of hash buckets for inode cache.
848 See header of drivers/scsi/in2000.c.
852 Run specified binary instead of /sbin/init as init
855 initcall_debug [KNL] Trace initcalls as they are executed. Useful
856 for working out where the kernel is dying during
859 initrd= [BOOT] Specify the location of the initial ramdisk
861 inport.irq= [HW] Inport (ATI XL and Microsoft) busmouse driver
879 intel_iommu= [DMAR] Intel IOMMU driver (DMAR) option
881 Disable intel iommu driver.
882 igfx_off [Default Off]
883 By default, gfx is mapped as normal device. If a gfx
884 device has a dedicated DMAR unit, the DMAR unit is
885 bypassed by not enabling DMAR with this option. In
886 this case, gfx device will use physical address for
889 With this option iommu will not optimize to look
890 for io virtual address below 32 bit forcing dual
891 address cycle on pci bus for cards supporting greater
892 than 32 bit addressing. The default is to look
893 for translation below 32 bit and if not available
894 then look in the higher range.
896 With this option on every unmap_single operation will
897 result in a hardware IOTLB flush operation as opposed
898 to batching them for performance.
900 io_delay= [X86-32,X86-64] I/O delay method
902 Standard port 0x80 based delay
904 Alternate port 0xed based delay (needed on some systems)
906 Simple two microseconds delay
910 io7= [HW] IO7 for Marvel based alpha systems
911 See comment before marvel_specify_io7 in
912 arch/alpha/kernel/core_marvel.c.
915 See Documentation/filesystems/nfsroot.txt.
917 ip2= [HW] Set IO/IRQ pairs for up to 4 IntelliPort boards
918 See comment before ip2_setup() in
919 drivers/char/ip2/ip2base.c.
921 ips= [HW,SCSI] Adaptec / IBM ServeRAID controller
922 See header of drivers/scsi/ips.c.
924 ports= [IP_VS_FTP] IPVS ftp helper module
926 Up to 8 (IP_VS_APP_MAX_PORTS) ports
928 Format: <port>,<port>....
931 When an interrupt is not handled search all handlers
932 for it. Intended to get systems with badly broken
936 When an interrupt is not handled search all handlers
937 for it. Also check all handlers each timer
938 interrupt. Intended to get systems with badly broken
942 Format: <RDP>,<reset>,<pci_scan>,<verbosity>
944 isolcpus= [KNL,SMP] Isolate CPUs from the general scheduler.
946 <cpu number>,...,<cpu number>
948 <cpu number>-<cpu number> (must be a positive range in ascending order)
950 <cpu number>,...,<cpu number>-<cpu number>
951 This option can be used to specify one or more CPUs
952 to isolate from the general SMP balancing and scheduling
953 algorithms. The only way to move a process onto or off
954 an "isolated" CPU is via the CPU affinity syscalls.
955 <cpu number> begins at 0 and the maximum value is
956 "number of CPUs in system - 1".
958 This option is the preferred way to isolate CPUs. The
959 alternative -- manually setting the CPU mask of all
960 tasks in the system -- can cause problems and
961 suboptimal load balancer performance.
965 js= [HW,JOY] Analog joystick
966 See Documentation/input/joystick.txt.
968 kernelcore=nn[KMG] [KNL,X86-32,IA-64,PPC,X86-64] This parameter
969 specifies the amount of memory usable by the kernel
970 for non-movable allocations. The requested amount is
971 spread evenly throughout all nodes in the system. The
972 remaining memory in each node is used for Movable
973 pages. In the event, a node is too small to have both
974 kernelcore and Movable pages, kernelcore pages will
975 take priority and other nodes will have a larger number
976 of kernelcore pages. The Movable zone is used for the
977 allocation of pages that may be reclaimed or moved
978 by the page migration subsystem. This means that
979 HugeTLB pages may not be allocated from this zone.
980 Note that allocations like PTEs-from-HighMem still
981 use the HighMem zone if it exists, and the Normal
984 movablecore=nn[KMG] [KNL,X86-32,IA-64,PPC,X86-64] This parameter
985 is similar to kernelcore except it specifies the
986 amount of memory used for migratable allocations.
987 If both kernelcore and movablecore is specified,
988 then kernelcore will be at *least* the specified
989 value but may be more. If movablecore on its own
990 is specified, the administrator must be careful
991 that the amount of memory usable for all allocations
996 kstack=N [X86-32,X86-64] Print N words from the kernel stack
999 kgdboc= [HW] kgdb over consoles.
1000 Requires a tty driver that supports console polling.
1001 (only serial suported for now)
1002 Format: <serial_device>[,baud]
1008 lapic [X86-32,APIC] Enable the local APIC even if BIOS
1011 lapic_timer_c2_ok [X86-32,x86-64,APIC] trust the local apic timer in
1014 libata.dma= [LIBATA] DMA control
1015 libata.dma=0 Disable all PATA and SATA DMA
1016 libata.dma=1 PATA and SATA Disk DMA only
1017 libata.dma=2 ATAPI (CDROM) DMA only
1018 libata.dma=4 Compact Flash DMA only
1019 Combinations also work, so libata.dma=3 enables DMA
1020 for disks and CDROMs, but not CFs.
1022 libata.noacpi [LIBATA] Disables use of ACPI in libata suspend/resume
1026 libata.force= [LIBATA] Force configurations. The format is comma
1027 separated list of "[ID:]VAL" where ID is
1028 PORT[:DEVICE]. PORT and DEVICE are decimal numbers
1029 matching port, link or device. Basically, it matches
1030 the ATA ID string printed on console by libata. If
1031 the whole ID part is omitted, the last PORT and DEVICE
1032 values are used. If ID hasn't been specified yet, the
1033 configuration applies to all ports, links and devices.
1035 If only DEVICE is omitted, the parameter applies to
1036 the port and all links and devices behind it. DEVICE
1037 number of 0 either selects the first device or the
1038 first fan-out link behind PMP device. It does not
1039 select the host link. DEVICE number of 15 selects the
1040 host link and device attached to it.
1042 The VAL specifies the configuration to force. As long
1043 as there's no ambiguity shortcut notation is allowed.
1044 For example, both 1.5 and 1.5G would work for 1.5Gbps.
1045 The following configurations can be forced.
1047 * Cable type: 40c, 80c, short40c, unk, ign or sata.
1048 Any ID with matching PORT is used.
1050 * SATA link speed limit: 1.5Gbps or 3.0Gbps.
1052 * Transfer mode: pio[0-7], mwdma[0-4] and udma[0-7].
1053 udma[/][16,25,33,44,66,100,133] notation is also
1056 * [no]ncq: Turn on or off NCQ.
1058 If there are multiple matching configurations changing
1059 the same attribute, the last one is used.
1061 load_ramdisk= [RAM] List of ramdisks to load from floppy
1062 See Documentation/ramdisk.txt.
1064 lockd.nlm_grace_period=P [NFS] Assign grace period.
1067 lockd.nlm_tcpport=N [NFS] Assign TCP port.
1070 lockd.nlm_timeout=T [NFS] Assign timeout value.
1073 lockd.nlm_udpport=M [NFS] Assign UDP port.
1076 logibm.irq= [HW,MOUSE] Logitech Bus Mouse Driver
1079 loglevel= All Kernel Messages with a loglevel smaller than the
1080 console loglevel will be printed to the console. It can
1081 also be changed with klogd or other programs. The
1082 loglevels are defined as follows:
1084 0 (KERN_EMERG) system is unusable
1085 1 (KERN_ALERT) action must be taken immediately
1086 2 (KERN_CRIT) critical conditions
1087 3 (KERN_ERR) error conditions
1088 4 (KERN_WARNING) warning conditions
1089 5 (KERN_NOTICE) normal but significant condition
1090 6 (KERN_INFO) informational
1091 7 (KERN_DEBUG) debug-level messages
1093 log_buf_len=n Sets the size of the printk ring buffer, in bytes.
1094 Format: { n | nk | nM }
1095 n must be a power of two. The default size
1096 is set in the kernel config file.
1098 logo.nologo [FB] Disables display of the built-in Linux logo.
1099 This may be used to provide more screen space for
1100 kernel log messages and is useful when debugging
1101 kernel boot problems.
1103 lp=0 [LP] Specify parallel ports to use, e.g,
1104 lp=port[,port...] lp=none,parport0 (lp0 not configured, lp1 uses
1105 lp=reset first parallel port). 'lp=0' disables the
1106 lp=auto printer driver. 'lp=reset' (which can be
1107 specified in addition to the ports) causes
1108 attached printers to be reset. Using
1109 lp=port1,port2,... specifies the parallel ports
1110 to associate lp devices with, starting with
1111 lp0. A port specification may be 'none' to skip
1112 that lp device, or a parport name such as
1113 'parport0'. Specifying 'lp=auto' instead of a
1114 port specification list means that device IDs
1115 from each port should be examined, to see if
1116 an IEEE 1284-compliant printer is attached; if
1117 so, the driver will manage that printer.
1118 See also header of drivers/char/lp.c.
1121 Sets loops_per_jiffy to given constant, thus avoiding
1122 time-consuming boot-time autodetection (up to 250 ms per
1123 CPU). 0 enables autodetection (default). To determine
1124 the correct value for your kernel, boot with normal
1125 autodetection and see what value is printed. Note that
1126 on SMP systems the preset will be applied to all CPUs,
1127 which is likely to cause problems if your CPUs need
1128 significantly divergent settings. An incorrect value
1129 will cause delays in the kernel to be wrong, leading to
1130 unpredictable I/O errors and other breakage. Although
1131 unlikely, in the extreme case this might damage your
1135 Format: <io>,<irq>,<dma>
1137 mac5380= [HW,SCSI] Format:
1138 <can_queue>,<cmd_per_lun>,<sg_tablesize>,<hostid>,<use_tags>
1140 machvec= [IA64] Force the use of a particular machine-vector
1141 (machvec) in a generic kernel.
1142 Example: machvec=hpzx1_swiotlb
1144 max_loop= [LOOP] Maximum number of loopback devices that can
1148 maxcpus= [SMP] Maximum number of processors that an SMP kernel
1149 should make use of. maxcpus=n : n >= 0 limits the
1150 kernel to using 'n' processors. n=0 is a special case,
1151 it is equivalent to "nosmp", which also disables
1154 max_addr=[KMG] [KNL,BOOT,ia64] All physical memory greater than or
1155 equal to this physical address is ignored.
1157 max_luns= [SCSI] Maximum number of LUNs to probe.
1158 Should be between 1 and 2^32-1.
1161 [SCSI] Maximum number of LUNs received.
1162 Should be between 1 and 16384.
1166 mce [X86-32] Machine Check Exception
1168 mce=option [X86-64] See Documentation/x86_64/boot-options.txt
1170 md= [HW] RAID subsystems devices and level
1171 See Documentation/md.txt.
1174 Format: <first>,<last>
1175 Specifies range of consoles to be captured by the MDA.
1177 mem=nn[KMG] [KNL,BOOT] Force usage of a specific amount of memory
1178 Amount of memory to be used when the kernel is not able
1179 to see the whole system memory or for test.
1180 [X86-32] Use together with memmap= to avoid physical
1181 address space collisions. Without memmap= PCI devices
1182 could be placed at addresses belonging to unused RAM.
1184 mem=nopentium [BUGS=X86-32] Disable usage of 4MB pages for kernel
1187 memmap=exactmap [KNL,X86-32,X86_64] Enable setting of an exact
1188 E820 memory map, as specified by the user.
1189 Such memmap=exactmap lines can be constructed based on
1190 BIOS output or other requirements. See the memmap=nn@ss
1193 memmap=nn[KMG]@ss[KMG]
1194 [KNL] Force usage of a specific region of memory
1195 Region of memory to be used, from ss to ss+nn.
1197 memmap=nn[KMG]#ss[KMG]
1198 [KNL,ACPI] Mark specific memory as ACPI data.
1199 Region of memory to be used, from ss to ss+nn.
1201 memmap=nn[KMG]$ss[KMG]
1202 [KNL,ACPI] Mark specific memory as reserved.
1203 Region of memory to be used, from ss to ss+nn.
1204 Example: Exclude memory from 0x18690000-0x1869ffff
1205 memmap=64K$0x18690000
1207 memmap=0x10000$0x18690000
1209 memtest= [KNL,X86_64] Enable memtest
1211 range: 0,4 : pattern number
1212 default : 0 <disable>
1214 meye.*= [HW] Set MotionEye Camera parameters
1215 See Documentation/video4linux/meye.txt.
1217 mfgpt_irq= [IA-32] Specify the IRQ to use for the
1218 Multi-Function General Purpose Timers on AMD Geode
1221 mfgptfix [X86-32] Fix MFGPT timers on AMD Geode platforms when
1222 the BIOS has incorrectly applied a workaround. TinyBIOS
1223 version 0.98 is known to be affected, 0.99 fixes the
1224 problem by letting the user disable the workaround.
1229 [MOUSE] Maximum time between finger touching and
1230 leaving touchpad surface for touch to be considered
1231 a tap and be reported as a left button click (for
1232 touchpads working in absolute mode only).
1234 mousedev.xres= [MOUSE] Horizontal screen resolution, used for devices
1235 reporting absolute coordinates, such as tablets
1236 mousedev.yres= [MOUSE] Vertical screen resolution, used for devices
1237 reporting absolute coordinates, such as tablets
1242 MTD_Partition= [MTD]
1243 Format: <name>,<region-number>,<size>,<offset>
1245 MTD_Region= [MTD] Format:
1246 <name>,<region-number>[,<base>,<size>,<buswidth>,<altbuswidth>]
1249 See drivers/mtd/cmdlinepart.c.
1252 ARM/S3C2412 JIVE boot control
1254 See arch/arm/mach-s3c2412/mach-jive.c
1256 mtouchusb.raw_coordinates=
1257 [HW] Make the MicroTouch USB driver use raw coordinates
1258 ('y', default) or cooked coordinates ('n')
1260 n2= [NET] SDL Inc. RISCom/N2 synchronous serial card
1263 See header of drivers/scsi/NCR_D700.c.
1267 ncr53c400= [HW,SCSI]
1269 ncr53c400a= [HW,SCSI]
1271 ncr53c406a= [HW,SCSI]
1273 ncr53c8xx= [HW,SCSI]
1275 netdev= [NET] Network devices parameters
1276 Format: <irq>,<io>,<mem_start>,<mem_end>,<name>
1277 Note that mem_start is often overloaded to mean
1278 something different and driver-specific.
1279 This usage is only documented in each driver source
1283 See Documentation/filesystems/nfsroot.txt.
1285 nfsroot= [NFS] nfs root filesystem for disk-less boxes.
1286 See Documentation/filesystems/nfsroot.txt.
1288 nfs.callback_tcpport=
1289 [NFS] set the TCP port on which the NFSv4 callback
1290 channel should listen.
1292 nfs.idmap_cache_timeout=
1293 [NFS] set the maximum lifetime for idmapper cache
1297 [NFS] enable 64-bit inode numbers.
1298 If zero, the NFS client will fake up a 32-bit inode
1299 number for the readdir() and stat() syscalls instead
1300 of returning the full 64-bit number.
1301 The default is to return 64-bit inode numbers.
1303 nmi_debug= [KNL,AVR32] Specify one or more actions to take
1304 when a NMI is triggered.
1305 Format: [state][,regs][,debounce][,die]
1307 nmi_watchdog= [KNL,BUGS=X86-32] Debugging features for SMP kernels
1309 no387 [BUGS=X86-32] Tells the kernel to use the 387 maths
1310 emulation library even if a 387 maths coprocessor
1313 noaliencache [MM, NUMA, SLAB] Disables the allocation of alien
1314 caches in the slab allocator. Saves per-node memory,
1315 but will impact performance.
1319 noapic [SMP,APIC] Tells the kernel to not make use of any
1320 IOAPICs that may be present in the system.
1322 nobats [PPC] Do not use BATs for mapping kernel lowmem
1323 on "Classic" PPC cores.
1327 nodelayacct [KNL] Disable per-task delay accounting
1329 nodisconnect [HW,SCSI,M68K] Disables SCSI disconnects.
1331 noefi [X86-32,X86-64] Disable EFI runtime services support.
1335 noexec [X86-32,X86-64]
1336 On X86-32 available only on PAE configured kernels.
1337 noexec=on: enable non-executable mappings (default)
1338 noexec=off: disable non-executable mappings
1341 This affects only 32-bit executables.
1342 noexec32=on: enable non-executable mappings (default)
1343 read doesn't imply executable mappings
1344 noexec32=off: disable non-executable mappings
1345 read implies executable mappings
1347 nofxsr [BUGS=X86-32] Disables x86 floating point extended
1348 register save and restore. The kernel will only save
1349 legacy floating-point registers on task switch.
1351 noclflush [BUGS=X86] Don't use the CLFLUSH instruction
1355 no-hlt [BUGS=X86-32] Tells the kernel that the hlt
1356 instruction doesn't work correctly and not to
1359 nohalt [IA-64] Tells the kernel not to use the power saving
1360 function PAL_HALT_LIGHT when idle. This increases
1361 power-consumption. On the positive side, it reduces
1362 interrupt wake-up latency, which may improve performance
1363 in certain environments such as networked servers or
1366 nohz= [KNL] Boottime enable/disable dynamic ticks
1367 Valid arguments: on, off
1370 noirqbalance [X86-32,SMP,KNL] Disable kernel irq balancing
1372 noirqdebug [X86-32] Disables the code which attempts to detect and
1373 disable unhandled interrupt sources.
1375 no_timer_check [X86-32,X86_64,APIC] Disables the code which tests for
1376 broken timer IRQ sources.
1378 noisapnp [ISAPNP] Disables ISA PnP code.
1380 noinitrd [RAM] Tells the kernel not to load any configured
1385 nojitter [IA64] Disables jitter checking for ITC timers.
1387 nolapic [X86-32,APIC] Do not enable or use the local APIC.
1389 nolapic_timer [X86-32,APIC] Do not use the local APIC timer.
1391 noltlbs [PPC] Do not use large page/tlb entries for kernel
1392 lowmem mapping on PPC40x.
1394 nomca [IA-64] Disable machine check abort handling
1396 nomce [X86-32] Machine Check Exception
1398 nomfgpt [X86-32] Disable Multi-Function General Purpose
1399 Timer usage (for AMD Geode machines).
1401 noreplace-paravirt [X86-32,PV_OPS] Don't patch paravirt_ops
1403 noreplace-smp [X86-32,SMP] Don't replace SMP instructions
1404 with UP alternatives
1406 noresidual [PPC] Don't use residual data on PReP machines.
1408 noresume [SWSUSP] Disables resume and restores original swap
1411 no-scroll [VGA] Disables scrollback.
1412 This is required for the Braillex ib80-piezo Braille
1413 reader made by F.H. Papenmeier (Germany).
1417 nosep [BUGS=X86-32] Disables x86 SYSENTER/SYSEXIT support.
1419 nosmp [SMP] Tells an SMP kernel to act as a UP kernel,
1420 and disable the IO APIC. legacy for "maxcpus=0".
1422 nosoftlockup [KNL] Disable the soft-lockup detector.
1424 nosync [HW,M68K] Disables sync negotiation for all devices.
1426 notsc [BUGS=X86-32] Disable Time Stamp Counter
1428 nousb [USB] Disable the USB subsystem
1432 nptcg= [IA64] Override max number of concurrent global TLB
1433 purges which is reported from either PAL_VM_SUMMARY or
1436 numa_zonelist_order= [KNL, BOOT] Select zonelist order for NUMA.
1437 one of ['zone', 'node', 'default'] can be specified
1438 This can be set from sysctl after boot.
1439 See Documentation/sysctl/vm.txt for details.
1441 nr_uarts= [SERIAL] maximum number of UARTs to be registered.
1443 olpc_ec_timeout= [OLPC] ms delay when issuing EC commands
1444 Rather than timing out after 20 ms if an EC
1445 command is not properly ACKed, override the length
1446 of the timeout. We have interrupts disabled while
1447 waiting for the ACK, so if this is set too high
1448 interrupts *may* be lost!
1453 oprofile.timer= [HW]
1454 Use timer interrupt instead of performance counters
1456 osst= [HW,SCSI] SCSI Tape Driver
1457 Format: <buffer_size>,<write_threshold>
1458 See also Documentation/scsi/st.txt.
1460 panic= [KNL] Kernel behaviour on panic
1463 parkbd.port= [HW] Parallel port number the keyboard adapter is
1464 connected to, default is 0.
1466 parkbd.mode= [HW] Parallel port keyboard adapter mode of operation,
1467 0 for XT, 1 for AT (default is AT).
1470 parport= [HW,PPT] Specify parallel ports. 0 disables.
1471 Format: { 0 | auto | 0xBBB[,IRQ[,DMA]] }
1472 Use 'auto' to force the driver to use any
1473 IRQ/DMA settings detected (the default is to
1474 ignore detected IRQ/DMA settings because of
1475 possible conflicts). You can specify the base
1476 address, IRQ, and DMA settings; IRQ and DMA
1477 should be numbers, or 'auto' (for using detected
1478 settings on that particular port), or 'nofifo'
1479 (to avoid using a FIFO even if it is detected).
1480 Parallel ports are assigned in the order they
1481 are specified on the command line, starting
1484 parport_init_mode= [HW,PPT]
1485 Configure VIA parallel port to operate in
1486 a specific mode. This is necessary on Pegasos
1487 computer where firmware has no options for setting
1488 up parallel port mode and sets it to spp.
1489 Currently this function knows 686a and 8231 chips.
1490 Format: [spp|ps2|epp|ecp|ecpepp]
1492 pas2= [HW,OSS] Format:
1493 <io>,<irq>,<dma>,<dma16>,<sb_io>,<sb_irq>,<sb_dma>,<sb_dma16>
1496 See header of drivers/scsi/pas16.c.
1499 Halt all CPUs after the first oops has been printed for
1500 the specified number of seconds. This is to be used if
1501 your oopses keep scrolling off the screen.
1506 See header of drivers/block/paride/pcd.c.
1507 See also Documentation/paride.txt.
1509 pci=option[,option...] [PCI] various PCI subsystem options:
1510 off [X86-32] don't probe for the PCI bus
1511 bios [X86-32] force use of PCI BIOS, don't access
1512 the hardware directly. Use this if your machine
1513 has a non-standard PCI host bridge.
1514 nobios [X86-32] disallow use of PCI BIOS, only direct
1515 hardware access methods are allowed. Use this
1516 if you experience crashes upon bootup and you
1517 suspect they are caused by the BIOS.
1518 conf1 [X86-32] Force use of PCI Configuration
1520 conf2 [X86-32] Force use of PCI Configuration
1522 noaer [PCIE] If the PCIEAER kernel config parameter is
1523 enabled, this kernel boot option can be used to
1524 disable the use of PCIE advanced error reporting.
1525 nodomains [PCI] Disable support for multiple PCI
1526 root domains (aka PCI segments, in ACPI-speak).
1527 nommconf [X86-32,X86_64] Disable use of MMCONFIG for PCI
1529 nomsi [MSI] If the PCI_MSI kernel config parameter is
1530 enabled, this kernel boot option can be used to
1531 disable the use of MSI interrupts system-wide.
1532 biosirq [X86-32] Use PCI BIOS calls to get the interrupt
1533 routing table. These calls are known to be buggy
1534 on several machines and they hang the machine
1535 when used, but on other computers it's the only
1536 way to get the interrupt routing table. Try
1537 this option if the kernel is unable to allocate
1538 IRQs or discover secondary PCI buses on your
1540 rom [X86-32] Assign address space to expansion ROMs.
1541 Use with caution as certain devices share
1542 address decoders between ROMs and other
1544 norom [X86-32,X86_64] Do not assign address space to
1545 expansion ROMs that do not already have
1546 BIOS assigned address ranges.
1547 irqmask=0xMMMM [X86-32] Set a bit mask of IRQs allowed to be
1548 assigned automatically to PCI devices. You can
1549 make the kernel exclude IRQs of your ISA cards
1551 pirqaddr=0xAAAAA [X86-32] Specify the physical address
1552 of the PIRQ table (normally generated
1553 by the BIOS) if it is outside the
1554 F0000h-100000h range.
1555 lastbus=N [X86-32] Scan all buses thru bus #N. Can be
1556 useful if the kernel is unable to find your
1557 secondary buses and you want to tell it
1558 explicitly which ones they are.
1559 assign-busses [X86-32] Always assign all PCI bus
1560 numbers ourselves, overriding
1561 whatever the firmware may have done.
1562 usepirqmask [X86-32] Honor the possible IRQ mask stored
1563 in the BIOS $PIR table. This is needed on
1564 some systems with broken BIOSes, notably
1565 some HP Pavilion N5400 and Omnibook XE3
1566 notebooks. This will have no effect if ACPI
1567 IRQ routing is enabled.
1568 noacpi [X86-32] Do not use ACPI for IRQ routing
1569 or for PCI scanning.
1570 use_crs [X86-32] Use _CRS for PCI resource
1572 routeirq Do IRQ routing for all PCI devices.
1573 This is normally done in pci_enable_device(),
1574 so this option is a temporary workaround
1575 for broken drivers that don't call it.
1576 skip_isa_align [X86] do not align io start addr, so can
1577 handle more pci cards
1578 firmware [ARM] Do not re-enumerate the bus but instead
1579 just use the configuration from the
1580 bootloader. This is currently used on
1581 IXP2000 systems where the bus has to be
1582 configured a certain way for adjunct CPUs.
1583 noearly [X86] Don't do any early type 1 scanning.
1584 This might help on some broken boards which
1585 machine check when some devices' config space
1586 is read. But various workarounds are disabled
1587 and some IOMMU drivers will not work.
1588 bfsort Sort PCI devices into breadth-first order.
1589 This sorting is done to get a device
1590 order compatible with older (<= 2.4) kernels.
1591 nobfsort Don't sort PCI devices into breadth-first order.
1592 cbiosize=nn[KMG] The fixed amount of bus space which is
1593 reserved for the CardBus bridge's IO window.
1594 The default value is 256 bytes.
1595 cbmemsize=nn[KMG] The fixed amount of bus space which is
1596 reserved for the CardBus bridge's memory
1597 window. The default value is 64 megabytes.
1599 pcmv= [HW,PCMCIA] BadgePAD 4
1602 See Documentation/paride.txt.
1604 pdcchassis= [PARISC,HW] Disable/Enable PDC Chassis Status codes at
1607 See arch/parisc/kernel/pdc_chassis.c
1610 See Documentation/paride.txt.
1613 See Documentation/paride.txt.
1615 pirq= [SMP,APIC] Manual mp-table setup
1616 See Documentation/i386/IO-APIC.txt.
1618 plip= [PPT,NET] Parallel port network link
1619 Format: { parport<nr> | timid | 0 }
1620 See also Documentation/parport.txt.
1622 pmtmr= [X86] Manual setup of pmtmr I/O Port.
1623 Override pmtimer IOPort with a hex value.
1630 { on | off | curr | res | no-curr | no-res }
1633 [ISAPNP] Exclude IRQs for the autoconfiguration
1636 [ISAPNP] Exclude DMAs for the autoconfiguration
1638 pnp_reserve_io= [ISAPNP] Exclude I/O ports for the autoconfiguration
1639 Ranges are in pairs (I/O port base and size).
1642 [ISAPNP] Exclude memory regions for the
1644 Ranges are in pairs (memory base and size).
1646 print-fatal-signals=
1647 [KNL] debug: print fatal signals
1648 print-fatal-signals=1: print segfault info to
1652 printk.time= Show timing data prefixed to each printk message line
1653 Format: <bool> (1/Y/y=enable, 0/N/n=disable)
1655 profile= [KNL] Enable kernel profiling via /proc/profile
1656 Format: [schedule,]<number>
1657 Param: "schedule" - profile schedule points.
1658 Param: <number> - step/bucket size as a power of 2 for
1659 statistical time based profiling.
1660 Param: "sleep" - profile D-state sleeping (millisecs).
1661 Requires CONFIG_SCHEDSTATS
1662 Param: "kvm" - profile VM exits.
1664 processor.max_cstate= [HW,ACPI]
1665 Limit processor to maximum C-state
1666 max_cstate=9 overrides any DMI blacklist limit.
1668 processor.nocst [HW,ACPI]
1669 Ignore the _CST method to determine C-states,
1670 instead using the legacy FADT method
1672 prompt_ramdisk= [RAM] List of RAM disks to prompt for floppy disk
1674 See Documentation/ramdisk.txt.
1676 psmouse.proto= [HW,MOUSE] Highest PS2 mouse protocol extension to
1677 probe for; one of (bare|imps|exps|lifebook|any).
1678 psmouse.rate= [HW,MOUSE] Set desired mouse report rate, in reports
1680 psmouse.resetafter= [HW,MOUSE]
1681 Try to reset the device after so many bad packets
1684 [HW,MOUSE] Set desired mouse resolution, in dpi.
1685 psmouse.smartscroll=
1686 [HW,MOUSE] Controls Logitech smartscroll autorepeat.
1687 0 = disabled, 1 = enabled (default).
1689 pss= [HW,OSS] Personal Sound System (ECHO ESC614)
1691 <io>,<mss_io>,<mss_irq>,<mss_dma>,<mpu_io>,<mpu_irq>
1694 See Documentation/paride.txt.
1697 [KNL] Number of legacy pty's. Overwrites compiled-in
1700 quiet [KNL] Disable most log messages
1705 See Documentation/md.txt.
1707 ramdisk_blocksize= [RAM]
1708 See Documentation/ramdisk.txt.
1710 ramdisk_size= [RAM] Sizes of RAM disks in kilobytes
1711 See Documentation/ramdisk.txt.
1713 rcupdate.blimit= [KNL,BOOT]
1714 Set maximum number of finished RCU callbacks to process
1717 rcupdate.qhimark= [KNL,BOOT]
1718 Set threshold of queued
1719 RCU callbacks over which batch limiting is disabled.
1721 rcupdate.qlowmark= [KNL,BOOT]
1722 Set threshold of queued RCU callbacks below which
1723 batch limiting is re-enabled.
1727 Run specified binary instead of /init from the ramdisk,
1728 used for early userspace startup. See initrd.
1730 reboot= [BUGS=X86-32,BUGS=ARM,BUGS=IA-64] Rebooting mode
1731 Format: <reboot_mode>[,<reboot_mode2>[,...]]
1732 See arch/*/kernel/reboot.c or arch/*/kernel/process.c
1735 [KNL, SMP] Set scheduler's default relax_domain_level.
1736 See Documentation/cpusets.txt.
1738 reserve= [KNL,BUGS] Force the kernel to ignore some iomem area
1740 reservetop= [X86-32]
1742 Reserves a hole at the top of the kernel virtual
1745 reset_devices [KNL] Force drivers to reset the underlying device
1746 during initialization.
1749 Specify the partition device for software suspend
1751 resume_offset= [SWSUSP]
1752 Specify the offset from the beginning of the partition
1753 given by "resume=" at which the swap header is located,
1754 in <PAGE_SIZE> units (needed only for swap files).
1755 See Documentation/power/swsusp-and-swap-files.txt
1757 retain_initrd [RAM] Keep initrd memory after extraction
1759 rhash_entries= [KNL,NET]
1760 Set number of hash buckets for route cache
1762 riscom8= [HW,SERIAL]
1763 Format: <io_board1>[,<io_board2>[,...<io_boardN>]]
1765 ro [KNL] Mount root device read-only on boot
1767 root= [KNL] Root filesystem
1769 rootdelay= [KNL] Delay (in seconds) to pause before attempting to
1770 mount the root filesystem
1772 rootflags= [KNL] Set root filesystem mount option string
1774 rootfstype= [KNL] Set root filesystem type
1776 rootwait [KNL] Wait (indefinitely) for root device to show up.
1777 Useful for devices that are detected asynchronously
1778 (e.g. USB and MMC devices).
1780 root_plug.vendor_id=
1781 [ROOTPLUG] Override the default vendor ID
1783 root_plug.product_id=
1784 [ROOTPLUG] Override the default product ID
1787 [ROOTPLUG] Enable debugging output
1789 rw [KNL] Mount root device read-write on boot
1791 S [KNL] Run init in single mode
1794 See drivers/net/irda/sa1100_ir.c.
1796 sbni= [NET] Granch SBNI12 leased line adapter
1798 sc1200wdt= [HW,WDT] SC1200 WDT (watchdog) driver
1799 Format: <io>[,<timeout>[,<isapnp>]]
1801 scsi_debug_*= [SCSI]
1802 See drivers/scsi/scsi_debug.c.
1804 scsi_default_dev_flags=
1805 [SCSI] SCSI default device flags
1808 scsi_dev_flags= [SCSI] Black/white list entry for vendor and model
1809 Format: <vendor>:<model>:<flags>
1810 (flags are integer value)
1812 scsi_logging_level= [SCSI] a bit mask of logging levels
1813 See drivers/scsi/scsi_logging.h for bits. Also
1814 settable via sysctl at dev.scsi.logging_level
1815 (/proc/sys/dev/scsi/logging_level).
1816 There is also a nice 'scsi_logging_level' script in the
1817 S390-tools package, available for download at
1818 http://www-128.ibm.com/developerworks/linux/linux390/s390-tools-1.5.4.html
1820 scsi_mod.scan= [SCSI] sync (default) scans SCSI busses as they are
1821 discovered. async scans them in kernel threads,
1822 allowing boot to proceed. none ignores them, expecting
1823 user space to do the scan.
1825 selinux [SELINUX] Disable or enable SELinux at boot time.
1826 Format: { "0" | "1" }
1827 See security/selinux/Kconfig help text.
1830 Default value is set via kernel config option.
1831 If enabled at boot time, /selinux/disable can be used
1832 later to disable prior to initial policy load.
1834 selinux_compat_net =
1835 [SELINUX] Set initial selinux_compat_net flag value.
1836 Format: { "0" | "1" }
1837 0 -- use new secmark-based packet controls
1838 1 -- use legacy packet controls
1839 Default value is 0 (preferred).
1840 Value can be changed at runtime via
1841 /selinux/compat_net.
1843 serialnumber [BUGS=X86-32]
1846 Maximal number of shapers.
1849 See header of drivers/scsi/sim710.c.
1856 slub_debug[=options[,slabs]] [MM, SLUB]
1857 Enabling slub_debug allows one to determine the
1858 culprit if slab objects become corrupted. Enabling
1859 slub_debug can create guard zones around objects and
1860 may poison objects when not in use. Also tracks the
1861 last alloc / free. For more information see
1862 Documentation/vm/slub.txt.
1864 slub_max_order= [MM, SLUB]
1865 Determines the maximum allowed order for slabs.
1866 A high setting may cause OOMs due to memory
1867 fragmentation. For more information see
1868 Documentation/vm/slub.txt.
1870 slub_min_objects= [MM, SLUB]
1871 The minimum number of objects per slab. SLUB will
1872 increase the slab order up to slub_max_order to
1873 generate a sufficiently large slab able to contain
1874 the number of objects indicated. The higher the number
1875 of objects the smaller the overhead of tracking slabs
1876 and the less frequently locks need to be acquired.
1877 For more information see Documentation/vm/slub.txt.
1879 slub_min_order= [MM, SLUB]
1880 Determines the mininum page order for slabs. Must be
1881 lower than slub_max_order.
1882 For more information see Documentation/vm/slub.txt.
1884 slub_nomerge [MM, SLUB]
1885 Disable merging of slabs with similar size. May be
1886 necessary if there is some reason to distinguish
1887 allocs to different slabs. Debug options disable
1888 merging on their own.
1889 For more information see Documentation/vm/slub.txt.
1892 Format: <io1>[,<io2>[,...,<io8>]]
1894 smp-alt-once [X86-32,SMP] On a hotplug CPU system, only
1895 attempt to substitute SMP alternatives once at boot.
1897 smsc-ircc2.nopnp [HW] Don't use PNP to discover SMC devices
1898 smsc-ircc2.ircc_cfg= [HW] Device configuration I/O port
1899 smsc-ircc2.ircc_sir= [HW] SIR base I/O port
1900 smsc-ircc2.ircc_fir= [HW] FIR base I/O port
1901 smsc-ircc2.ircc_irq= [HW] IRQ line
1902 smsc-ircc2.ircc_dma= [HW] DMA channel
1903 smsc-ircc2.ircc_transceiver= [HW] Transceiver type:
1904 0: Toshiba Satellite 1800 (GP data pin select)
1905 1: Fast pin select (default)
1908 snd-ad1816a= [HW,ALSA]
1910 snd-ad1848= [HW,ALSA]
1912 snd-ali5451= [HW,ALSA]
1914 snd-als100= [HW,ALSA]
1916 snd-als4000= [HW,ALSA]
1918 snd-azt2320= [HW,ALSA]
1920 snd-cmi8330= [HW,ALSA]
1922 snd-cmipci= [HW,ALSA]
1924 snd-cs4231= [HW,ALSA]
1926 snd-cs4232= [HW,ALSA]
1928 snd-cs4236= [HW,ALSA]
1930 snd-cs4281= [HW,ALSA]
1932 snd-cs46xx= [HW,ALSA]
1934 snd-dt019x= [HW,ALSA]
1936 snd-dummy= [HW,ALSA]
1938 snd-emu10k1= [HW,ALSA]
1940 snd-ens1370= [HW,ALSA]
1942 snd-ens1371= [HW,ALSA]
1944 snd-es968= [HW,ALSA]
1946 snd-es1688= [HW,ALSA]
1948 snd-es18xx= [HW,ALSA]
1950 snd-es1938= [HW,ALSA]
1952 snd-es1968= [HW,ALSA]
1954 snd-fm801= [HW,ALSA]
1956 snd-gusclassic= [HW,ALSA]
1958 snd-gusextreme= [HW,ALSA]
1960 snd-gusmax= [HW,ALSA]
1964 snd-ice1712= [HW,ALSA]
1966 snd-intel8x0= [HW,ALSA]
1968 snd-interwave= [HW,ALSA]
1973 snd-korg1212= [HW,ALSA]
1975 snd-maestro3= [HW,ALSA]
1977 snd-mpu401= [HW,ALSA]
1979 snd-mtpav= [HW,ALSA]
1981 snd-nm256= [HW,ALSA]
1983 snd-opl3sa2= [HW,ALSA]
1991 snd-opti93x= [HW,ALSA]
1995 snd-rme32= [HW,ALSA]
1997 snd-rme96= [HW,ALSA]
1999 snd-rme9652= [HW,ALSA]
2005 snd-sbawe= [HW,ALSA]
2007 snd-serial= [HW,ALSA]
2009 snd-sgalaxy= [HW,ALSA]
2011 snd-sonicvibes= [HW,ALSA]
2016 snd-sun-cs4231= [HW,ALSA]
2018 snd-trident= [HW,ALSA]
2020 snd-usb-audio= [HW,ALSA,USB]
2022 snd-via82xx= [HW,ALSA]
2024 snd-virmidi= [HW,ALSA]
2026 snd-wavefront= [HW,ALSA]
2028 snd-ymfpci= [HW,ALSA]
2030 sonypi.*= [HW] Sony Programmable I/O Control Device driver
2031 See Documentation/sonypi.txt
2033 specialix= [HW,SERIAL] Specialix multi-serial port adapter
2034 See Documentation/specialix.txt.
2036 spia_io_base= [HW,MTD]
2042 Format: <io>,<irq>,<dma>,<mpu_io>,<mpu_irq>
2044 st= [HW,SCSI] SCSI tape parameters (buffers, etc.)
2045 See Documentation/scsi/st.txt.
2049 Set the STI (builtin display/keyboard on the HP-PARISC
2050 machines) console (graphic card) which should be used
2051 as the initial boot-console.
2052 See also comment in drivers/video/console/sticore.c.
2055 See comment in drivers/video/console/sticore.c.
2058 Format: bpp:<bpp1>[:<bpp2>[:<bpp3>...]]
2062 Control how the NFS server code allocates CPUs to
2063 service thread pools. Depending on how many NICs
2064 you have and where their interrupts are bound, this
2065 option will affect which CPUs will do NFS serving.
2066 Note: this parameter cannot be changed while the
2067 NFS server is running.
2069 auto the server chooses an appropriate mode
2070 automatically using heuristics
2071 global a single global pool contains all CPUs
2072 percpu one pool for each CPU
2073 pernode one pool for each NUMA node (equivalent
2074 to global on non-NUMA machines)
2076 swiotlb= [IA-64] Number of I/O TLB slabs
2080 sym53c416= [HW,SCSI]
2081 See header of drivers/scsi/sym53c416.c.
2083 sysrq_always_enabled
2085 Ignore sysrq setting - this boot parameter will
2086 neutralize any effect of /proc/sys/kernel/sysrq.
2087 Useful for debugging.
2090 See header of drivers/scsi/t128.c.
2094 thash_entries= [KNL,NET]
2095 Set number of hash buckets for TCP connection
2097 thermal.act= [HW,ACPI]
2098 -1: disable all active trip points in all thermal zones
2099 <degrees C>: override all lowest active trip points
2101 thermal.crt= [HW,ACPI]
2102 -1: disable all critical trip points in all thermal zones
2103 <degrees C>: lower all critical trip points
2105 thermal.nocrt= [HW,ACPI]
2106 Set to disable actions on ACPI thermal zone
2107 critical and hot trip points.
2109 thermal.off= [HW,ACPI]
2110 1: disable ACPI thermal control
2112 thermal.psv= [HW,ACPI]
2113 -1: disable all passive trip points
2114 <degrees C>: override all passive trip points to this value
2116 thermal.tzp= [HW,ACPI]
2117 Specify global default ACPI thermal zone polling rate
2118 <deci-seconds>: poll all this frequency
2119 0: no polling (default)
2121 tipar.timeout= [HW,PPT]
2122 Set communications timeout in tenths of a second
2125 tipar.delay= [HW,PPT]
2126 Set inter-bit delay in microseconds (default 10).
2129 See comment before function dc390_setup() in
2130 drivers/scsi/tmscsim.c.
2134 trix= [HW,OSS] MediaTrix AudioTrix Pro
2136 <io>,<irq>,<dma>,<dma2>,<sb_io>,<sb_irq>,<sb_dma>,<mpu_io>,<mpu_irq>
2138 turbografx.map[2|3]= [HW,JOY]
2139 TurboGraFX parallel port interface
2141 <port#>,<js1>,<js2>,<js3>,<js4>,<js5>,<js6>,<js7>
2142 See also Documentation/input/joystick-parport.txt
2144 u14-34f= [HW,SCSI] UltraStor 14F/34F SCSI host adapter
2145 See header of drivers/scsi/u14-34f.c.
2154 [USB] Ignore overcurrent events (default N).
2155 Some badly-designed motherboards generate lots of
2156 bogus events, for ports that aren't wired to
2157 anything. Set this parameter to avoid log spamming.
2158 Note that genuine overcurrent events won't be
2161 usbcore.autosuspend=
2162 [USB] The autosuspend time delay (in seconds) used
2163 for newly-detected USB devices (default 2). This
2164 is the time required before an idle device will be
2165 autosuspended. Devices for which the delay is set
2166 to a negative value won't be autosuspended at all.
2169 [USBHID] The interval which mice are to be polled at.
2171 add_efi_memmap [EFI; x86-32,X86-64] Include EFI memory map in
2172 kernel's map of available physical RAM.
2174 vdso= [X86-32,SH,x86-64]
2175 vdso=2: enable compat VDSO (default with COMPAT_VDSO)
2176 vdso=1: enable VDSO (default)
2177 vdso=0: disable VDSO mapping
2179 vdso32= [X86-32,X86-64]
2180 vdso32=2: enable compat VDSO (default with COMPAT_VDSO)
2181 vdso32=1: enable 32-bit VDSO (default)
2182 vdso32=0: disable 32-bit VDSO mapping
2185 vector=percpu: enable percpu vector domain
2187 video= [FB] Frame buffer configuration
2188 See Documentation/fb/modedb.txt.
2190 vga= [BOOT,X86-32] Select a particular video mode
2191 See Documentation/i386/boot.txt and
2192 Documentation/svga.txt.
2193 Use vga=ask for menu.
2194 This is actually a boot loader parameter; the value is
2195 passed to the kernel using a special protocol.
2197 vmalloc=nn[KMG] [KNL,BOOT] Forces the vmalloc area to have an exact
2198 size of <nn>. This can be used to increase the
2199 minimum size (128MB on x86). It can also be used to
2200 decrease the size and leave more room for directly
2203 vmhalt= [KNL,S390] Perform z/VM CP command after system halt.
2206 vmpanic= [KNL,S390] Perform z/VM CP command after kernel panic.
2209 vmpoff= [KNL,S390] Perform z/VM CP command after power off.
2212 waveartist= [HW,OSS]
2213 Format: <io>,<irq>,<dma>,<dma2>
2216 See header of drivers/scsi/wd33c93.c.
2219 See header of drivers/scsi/wd7000.c.
2222 See Documentation/watchdog/wdt.txt.
2224 xd= [HW,XT] Original XT pre-IDE (RLL encoded) disks.
2225 xd_geo= See header of drivers/block/xd.c.
2227 xirc2ps_cs= [NET,PCMCIA]
2229 <irq>,<irq_mask>,<io>,<full_duplex>,<do_sound>,<lockup_hack>[,<irq2>[,<irq3>[,<irq4>]]]
2231 norandmaps Don't use address space randomization
2232 Equivalent to echo 0 > /proc/sys/kernel/randomize_va_space
2234 ______________________________________________________________________
2238 Add documentation for ALSA options.
2239 Add more DRM drivers.