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 (hibernation) is enabled.
91 SUSPEND System suspend states are enabled.
92 TS Appropriate touchscreen support is enabled.
93 USB USB support is enabled.
94 USBHID USB Human Interface Device support is enabled.
95 V4L Video For Linux support is enabled.
96 VGA The VGA console has been enabled.
97 VT Virtual terminal support is enabled.
98 WDT Watchdog support is enabled.
99 XT IBM PC/XT MFM hard disk support is enabled.
100 X86-32 X86-32, aka i386 architecture is enabled.
101 X86-64 X86-64 architecture is enabled.
102 More X86-64 boot options can be found in
103 Documentation/x86_64/boot-options.txt .
105 In addition, the following text indicates that the option:
107 BUGS= Relates to possible processor bugs on the said processor.
108 KNL Is a kernel start-up parameter.
109 BOOT Is a boot loader parameter.
111 Parameters denoted with BOOT are actually interpreted by the boot
112 loader, and have no meaning to the kernel directly.
113 Do not modify the syntax of boot loader parameters without extreme
114 need or coordination with <Documentation/i386/boot.txt>.
116 There are also arch-specific kernel-parameters not documented here.
117 See for example <Documentation/x86_64/boot-options.txt>.
119 Note that ALL kernel parameters listed below are CASE SENSITIVE, and that
120 a trailing = on the name of any parameter states that that parameter will
121 be entered as an environment variable, whereas its absence indicates that
122 it will appear as a kernel argument readable via /proc/cmdline by programs
123 running once the system is up.
125 The number of kernel parameters is not limited, but the length of the
126 complete command line (parameters including spaces etc.) is limited to
127 a fixed number of characters. This limit depends on the architecture
128 and is between 256 and 4096 characters. It is defined in the file
129 ./include/asm/setup.h as COMMAND_LINE_SIZE.
132 acpi= [HW,ACPI,X86-64,i386]
133 Advanced Configuration and Power Interface
134 Format: { force | off | ht | strict | noirq }
135 force -- enable ACPI if default was off
136 off -- disable ACPI if default was on
137 noirq -- do not use ACPI for IRQ routing
138 ht -- run only enough ACPI to enable Hyper Threading
139 strict -- Be less tolerant of platforms that are not
140 strictly ACPI specification compliant.
142 See also Documentation/power/pm.txt, pci=noacpi
144 acpi_apic_instance= [ACPI, IOAPIC]
146 2: use 2nd APIC table, if available
147 1,0: use 1st APIC table
150 acpi_sleep= [HW,ACPI] Sleep options
151 Format: { s3_bios, s3_mode, s3_beep, s4_nohwsig, old_ordering }
152 See Documentation/power/video.txt for s3_bios and s3_mode.
153 s3_beep is for debugging; it makes the PC's speaker beep
154 as soon as the kernel's real-mode entry point is called.
155 s4_nohwsig prevents ACPI hardware signature from being
156 used during resume from hibernation.
157 old_ordering causes the ACPI 1.0 ordering of the _PTS
158 control method, wrt putting devices into low power
159 states, to be enforced (the ACPI 2.0 ordering of _PTS is
162 acpi_sci= [HW,ACPI] ACPI System Control Interrupt trigger mode
163 Format: { level | edge | high | low }
165 acpi_irq_balance [HW,ACPI]
166 ACPI will balance active IRQs
169 acpi_irq_nobalance [HW,ACPI]
170 ACPI will not move active IRQs (default)
173 acpi_irq_pci= [HW,ACPI] If irq_balance, clear listed IRQs for
175 Format: <irq>,<irq>...
177 acpi_irq_isa= [HW,ACPI] If irq_balance, mark listed IRQs used by ISA
178 Format: <irq>,<irq>...
180 acpi_no_auto_ssdt [HW,ACPI] Disable automatic loading of SSDT
182 acpi_os_name= [HW,ACPI] Tell ACPI BIOS the name of the OS
183 Format: To spoof as Windows 98: ="Microsoft Windows"
185 acpi_osi= [HW,ACPI] Modify list of supported OS interface strings
186 acpi_osi="string1" # add string1 -- only one string
187 acpi_osi="!string2" # remove built-in string2
188 acpi_osi= # disable all strings
190 acpi_serialize [HW,ACPI] force serialization of AML methods
192 acpi_skip_timer_override [HW,ACPI]
193 Recognize and ignore IRQ0/pin2 Interrupt Override.
194 For broken nForce2 BIOS resulting in XT-PIC timer.
195 acpi_use_timer_override [HW,ACPI}
196 Use timer override. For some broken Nvidia NF5 boards
197 that require a timer override, but don't have
200 acpi.debug_layer= [HW,ACPI]
202 Each bit of the <int> indicates an ACPI debug layer,
203 1: enable, 0: disable. It is useful for boot time
204 debugging. After system has booted up, it can be set
205 via /sys/module/acpi/parameters/debug_layer.
206 CONFIG_ACPI_DEBUG must be enabled for this to produce any output.
207 Available bits (add the numbers together) to enable debug output
208 for specific parts of the ACPI subsystem:
209 0x01 utilities 0x02 hardware 0x04 events 0x08 tables
210 0x10 namespace 0x20 parser 0x40 dispatcher
211 0x80 executer 0x100 resources 0x200 acpica debugger
212 0x400 os services 0x800 acpica disassembler.
213 The number can be in decimal or prefixed with 0x in hex.
214 Warning: Many of these options can produce a lot of
215 output and make your system unusable. Be very careful.
217 acpi.debug_level= [HW,ACPI]
219 Each bit of the <int> indicates an ACPI debug level,
220 1: enable, 0: disable. It is useful for boot time
221 debugging. After system has booted up, it can be set
222 via /sys/module/acpi/parameters/debug_level.
223 CONFIG_ACPI_DEBUG must be enabled for this to produce any output.
224 Available bits (add the numbers together) to enable different
225 debug output levels of the ACPI subsystem:
226 0x01 error 0x02 warn 0x04 init 0x08 debug object
227 0x10 info 0x20 init names 0x40 parse 0x80 load
228 0x100 dispatch 0x200 execute 0x400 names 0x800 operation region
229 0x1000 bfield 0x2000 tables 0x4000 values 0x8000 objects
230 0x10000 resources 0x20000 user requests 0x40000 package.
231 The number can be in decimal or prefixed with 0x in hex.
232 Warning: Many of these options can produce a lot of
233 output and make your system unusable. Be very careful.
235 acpi_pm_good [X86-32,X86-64]
236 Override the pmtimer bug detection: force the kernel
237 to assume that this machine's pmtimer latches its value
238 and always returns good values.
241 { off | try_unsupported }
242 off: disable AGP support
243 try_unsupported: try to drive unsupported chipsets
244 (may crash computer or cause data corruption)
246 enable_timer_pin_1 [i386,x86-64]
247 Enable PIN 1 of APIC timer
248 Can be useful to work around chipset bugs
249 (in particular on some ATI chipsets).
250 The kernel tries to set a reasonable default.
252 disable_timer_pin_1 [i386,x86-64]
253 Disable PIN 1 of APIC timer
254 Can be useful to work around chipset bugs.
257 Format: <io>,<irq>,<dma>,<dma2>,<type>
260 See header of drivers/scsi/advansys.c.
262 advwdt= [HW,WDT] Advantech WDT
263 Format: <iostart>,<iostop>
265 aedsp16= [HW,OSS] Audio Excel DSP 16
266 Format: <io>,<irq>,<dma>,<mss_io>,<mpu_io>,<mpu_irq>
267 See also header of sound/oss/aedsp16.c.
270 See Documentation/scsi/aha152x.txt.
273 Format: <portbase>[,<buson>,<busoff>[,<dmaspeed>]]
276 See Documentation/scsi/aic7xxx.txt.
279 See Documentation/scsi/aic79xx.txt.
281 amd_iommu= [HW,X86-84]
282 Pass parameters to the AMD IOMMU driver in the system.
284 isolate - enable device isolation (each device, as far
285 as possible, will get its own protection
287 amd_iommu_size= [HW,X86-64]
288 Define the size of the aperture for the AMD IOMMU
289 driver. Possible values are:
290 '32M', '64M' (default), '128M', '256M', '512M', '1G'
292 amijoy.map= [HW,JOY] Amiga joystick support
293 Map of devices attached to JOY0DAT and JOY1DAT
295 See also Documentation/kernel/input/joystick.txt
297 analog.map= [HW,JOY] Analog joystick and gamepad support
298 Specifies type or capabilities of an analog joystick
299 connected to one of 16 gameports
300 Format: <type1>,<type2>,..<type16>
303 Power management functions (SPARCstation-4/5 + deriv.)
305 Disable APC CPU standby support. SPARCstation-Fox does
306 not play well with APC CPU idle - disable it if you have
307 APC and your system crashes randomly.
309 apic= [APIC,i386] Advanced Programmable Interrupt Controller
310 Change the output verbosity whilst booting
311 Format: { quiet (default) | verbose | debug }
312 Change the amount of debugging information output
313 when initialising the APIC and IO-APIC components.
315 apm= [APM] Advanced Power Management
316 See header of arch/x86/kernel/apm_32.c.
318 arcrimi= [HW,NET] ARCnet - "RIM I" (entirely mem-mapped) cards
319 Format: <io>,<irq>,<nodeID>
323 atarimouse= [HW,MOUSE] Atari Mouse
325 atascsi= [HW,SCSI] Atari SCSI
327 atkbd.extra= [HW] Enable extra LEDs and keys on IBM RapidAccess,
328 EzKey and similar keyboards
330 atkbd.reset= [HW] Reset keyboard during initialization
332 atkbd.set= [HW] Select keyboard code set
333 Format: <int> (2 = AT (default), 3 = PS/2)
335 atkbd.scroll= [HW] Enable scroll wheel on MS Office and similar
338 atkbd.softraw= [HW] Choose between synthetic and real raw mode
339 Format: <bool> (0 = real, 1 = synthetic (default))
341 atkbd.softrepeat= [HW]
342 Use software keyboard repeat
346 baycom_epp= [HW,AX25]
349 baycom_par= [HW,AX25] BayCom Parallel Port AX.25 Modem
351 See header of drivers/net/hamradio/baycom_par.c.
353 baycom_ser_fdx= [HW,AX25]
354 BayCom Serial Port AX.25 Modem (Full Duplex Mode)
355 Format: <io>,<irq>,<mode>[,<baud>]
356 See header of drivers/net/hamradio/baycom_ser_fdx.c.
358 baycom_ser_hdx= [HW,AX25]
359 BayCom Serial Port AX.25 Modem (Half Duplex Mode)
360 Format: <io>,<irq>,<mode>
361 See header of drivers/net/hamradio/baycom_ser_hdx.c.
363 boot_delay= Milliseconds to delay each printk during boot.
364 Values larger than 10 seconds (10000) are changed to
368 bootmem_debug [KNL] Enable bootmem allocator debug messages.
370 bttv.card= [HW,V4L] bttv (bt848 + bt878 based grabber cards)
371 bttv.radio= Most important insmod options are available as
373 bttv.pll= See Documentation/video4linux/bttv/Insmod-options
374 bttv.tuner= and Documentation/video4linux/bttv/CARDLIST
377 See drivers/scsi/BusLogic.c, comment before function
378 BusLogic_ParseDriverOptions().
380 c101= [NET] Moxa C101 synchronous serial card
382 cachesize= [BUGS=X86-32] Override level 2 CPU cache size detection.
383 Sometimes CPU hardware bugs make them report the cache
384 size incorrectly. The kernel will attempt work arounds
385 to fix known problems, but for some CPUs it is not
386 possible to determine what the correct size should be.
387 This option provides an override for these situations.
389 security= [SECURITY] Choose a security module to enable at boot.
390 If this boot parameter is not specified, only the first
391 security module asking for security registration will be
392 loaded. An invalid security module name will be treated
393 as if no module has been chosen.
396 [SECURITY] Disable capabilities. This would normally
397 be used only if an alternative security model is to be
398 configured. Potentially dangerous and should only be
399 used if you are entirely sure of the consequences.
401 ccw_timeout_log [S390]
402 See Documentation/s390/CommonIO for details.
404 cgroup_disable= [KNL] Disable a particular controller
405 Format: {name of the controller(s) to disable}
406 {Currently supported controllers - "memory"}
408 checkreqprot [SELINUX] Set initial checkreqprot flag value.
409 Format: { "0" | "1" }
410 See security/selinux/Kconfig help text.
411 0 -- check protection applied by kernel (includes
412 any implied execute protection).
413 1 -- check protection requested by application.
414 Default value is set via a kernel config option.
415 Value can be changed at runtime via
416 /selinux/checkreqprot.
419 See Documentation/s390/CommonIO for details.
421 clock= [BUGS=X86-32, HW] gettimeofday clocksource override.
423 Forces specified clocksource (if available) to be used
424 when calculating gettimeofday(). If specified
425 clocksource is not available, it defaults to PIT.
426 Format: { pit | tsc | cyclone | pmtmr }
428 clocksource= [GENERIC_TIME] Override the default clocksource
430 Override the default clocksource and use the clocksource
431 with the name specified.
432 Some clocksource names to choose from, depending on
434 [all] jiffies (this is the base, fallback clocksource)
436 [ARM] imx_timer1,OSTS,netx_timer,mpu_timer2,
437 pxa_timer,timer3,32k_counter,timer0_1
439 [X86-32] pit,hpet,tsc,vmi-timer;
440 scx200_hrt on Geode; cyclone on IBM x440
448 clearcpuid=BITNUM [X86]
449 Disable CPUID feature X for the kernel. See
450 include/asm-x86/cpufeature.h for the valid bit numbers.
451 Note the Linux specific bits are not necessarily
452 stable over kernel options, but the vendor specific
454 Also note that user programs calling CPUID directly
455 or using the feature without checking anything
456 will still see it. This just prevents it from
457 being used by the kernel or shown in /proc/cpuinfo.
458 Also note the kernel might malfunction if you disable
461 code_bytes [IA32/X86_64] How many bytes of object code to print
468 [IA32/X86_64] Disable/Enable interrupt 0 timer routing
469 over the 8254 in addition to over the IO-APIC. The
470 kernel tries to set a sensible default.
472 hpet= [X86-32,HPET] option to control HPET usage
473 Format: { enable (default) | disable | force }
474 disable: disable HPET and use PIT instead
475 force: allow force enabled of undocumented chips (ICH4,
478 com20020= [HW,NET] ARCnet - COM20020 chipset
480 <io>[,<irq>[,<nodeID>[,<backplane>[,<ckp>[,<timeout>]]]]]
482 com90io= [HW,NET] ARCnet - COM90xx chipset (IO-mapped buffers)
486 ARCnet - COM90xx chipset (memory-mapped buffers)
487 Format: <io>[,<irq>[,<memstart>]]
489 condev= [HW,S390] console device
492 console= [KNL] Output console device and options.
494 tty<n> Use the virtual console device <n>.
498 Use the specified serial port. The options are of
499 the form "bbbbpnf", where "bbbb" is the baud rate,
500 "p" is parity ("n", "o", or "e"), "n" is number of
501 bits, and "f" is flow control ("r" for RTS or
502 omit it). Default is "9600n8".
504 See Documentation/serial-console.txt for more
506 Documentation/networking/netconsole.txt for an
509 uart[8250],io,<addr>[,options]
510 uart[8250],mmio,<addr>[,options]
511 Start an early, polled-mode console on the 8250/16550
512 UART at the specified I/O port or MMIO address,
513 switching to the matching ttyS device later. The
514 options are the same as for ttyS, above.
516 If the device connected to the port is not a TTY but a braille
517 device, prepend "brl," before the device type, for instance
519 For now, only VisioBraille is supported.
521 earlycon= [KNL] Output early console device and options.
522 uart[8250],io,<addr>[,options]
523 uart[8250],mmio,<addr>[,options]
524 Start an early, polled-mode console on the 8250/16550
525 UART at the specified I/O port or MMIO address.
526 The options are the same as for ttyS, above.
529 [HW] Never suspend the console
530 Disable suspending of consoles during suspend and
531 hibernate operations. Once disabled, debugging
532 messages can reach various consoles while the rest
533 of the system is being put to sleep (ie, while
534 debugging driver suspend/resume hooks). This may
535 not work reliably with all consoles, but is known
536 to work with serial and VGA consoles.
538 cpcihp_generic= [HW,PCI] Generic port I/O CompactPCI driver
540 <first_slot>,<last_slot>,<port>,<enum_bit>[,<debug>]
542 crashkernel=nn[KMG]@ss[KMG]
543 [KNL] Reserve a chunk of physical memory to
544 hold a kernel to switch to with kexec on panic.
546 crashkernel=range1:size1[,range2:size2,...][@offset]
547 [KNL] Same as above, but depends on the memory
548 in the running system. The syntax of range is
549 start-[end] where start and end are both
550 a memory unit (amount[KMG]). See also
551 Documentation/kdump/kdump.txt for a example.
554 Format: <io>,<irq>,<dma>,<dma2>,<mpuio>,<mpuirq>
559 cs89x0_media= [HW,NET]
560 Format: { rj45 | aui | bnc }
563 See header of drivers/s390/block/dasd_devmap.c.
565 db9.dev[2|3]= [HW,JOY] Multisystem joystick support via parallel port
566 (one device per port)
567 Format: <port#>,<type>
568 See also Documentation/input/joystick-parport.txt
570 debug [KNL] Enable kernel debugging (events log level).
573 [KNL] verbose self-tests
575 Print debugging info while doing the locking API
577 We default to 0 (no extra messages), setting it to
578 1 will print _a lot_ more information - normally
579 only useful to kernel developers.
581 debug_objects [KNL] Enable object debugging
583 debugpat [X86] Enable PAT debugging
585 decnet.addr= [HW,NET]
586 Format: <area>[,<node>]
587 See also Documentation/networking/decnet.txt.
590 Format: <blue0>,<blue1>,<blue2>,...,<blue15>
591 Change the default blue palette of the console.
592 This is a 16-member array composed of values
596 Format: <green0>,<green1>,<green2>,...,<green15>
597 Change the default green palette of the console.
598 This is a 16-member array composed of values
602 Format: <red0>,<red1>,<red2>,...,<red15>
603 Change the default red palette of the console.
604 This is a 16-member array composed of values
610 Set system-wide default UTF-8 mode for all tty's.
611 Default is 1, i.e. UTF-8 mode is enabled for all
612 newly opened terminals.
615 Set number of hash buckets for dentry cache.
618 IO parameters + enable/disable command.
620 digiepca= [HW,SERIAL]
621 See drivers/char/README.epca and
622 Documentation/digiepca.txt.
624 disable_mtrr_cleanup [X86]
625 enable_mtrr_cleanup [X86]
626 The kernel tries to adjust MTRR layout from continuous
627 to discrete, to make X server driver able to add WB
628 entry later. This parameter enables/disables that.
630 mtrr_chunk_size=nn[KMG] [X86]
631 used for mtrr cleanup. It is largest continous chunk
632 that could hold holes aka. UC entries.
634 mtrr_gran_size=nn[KMG] [X86]
635 Used for mtrr cleanup. It is granularity of mtrr block.
637 Large value could prevent small alignment from
640 mtrr_spare_reg_nr=n [X86]
642 Range: 0,7 : spare reg number
644 Used for mtrr cleanup. It is spare mtrr entries number.
645 Set to 2 or more if your graphical card needs more.
647 disable_mtrr_trim [X86, Intel and AMD only]
648 By default the kernel will trim any uncacheable
649 memory out of your available memory pool based on
650 MTRR settings. This parameter disables that behavior,
651 possibly causing your machine to run very slowly.
653 dmasound= [HW,OSS] Sound subsystem buffers
659 earlyprintk= [X86-32,X86-64,SH,BLACKFIN]
661 earlyprintk=serial[,ttySn[,baudrate]]
663 Append ",keep" to not disable it when the real console
666 Only vga or serial at a time, not both.
668 Currently only ttyS0 and ttyS1 are supported.
670 Interaction with the standard serial driver is not
673 The VGA output is eventually overwritten by the real
679 Format: {"off" | "on" | "skip[mbr]"}
681 eisa_irq_edge= [PARISC,HW]
682 See header of drivers/parisc/eisa.c.
685 See comment before function elanfreq_setup() in
686 arch/x86/kernel/cpu/cpufreq/elanfreq.c.
689 Format: {"anticipatory" | "cfq" | "deadline" | "noop"}
690 See Documentation/block/as-iosched.txt and
691 Documentation/block/deadline-iosched.txt for details.
693 elfcorehdr= [X86-32, X86_64]
694 Specifies physical address of start of kernel core
695 image elf header. Generally kexec loader will
696 pass this option to capture kernel.
697 See Documentation/kdump/kdump.txt for details.
699 enforcing [SELINUX] Set initial enforcing status.
701 See security/selinux/Kconfig help text.
702 0 -- permissive (log only, no denials).
703 1 -- enforcing (deny and log).
705 Value can be changed at runtime via /selinux/enforce.
708 Format: <spdif>,[<nomix>,[<amplifier>]]
709 See also header of sound/oss/es1371.c.
711 ether= [HW,NET] Ethernet cards parameters
712 This option is obsoleted by the "netdev=" option, which
713 has equivalent usage. See its documentation for details.
715 eurwdt= [HW,WDT] Eurotech CPU-1220/1410 onboard watchdog.
720 fail_make_request=[KNL]
721 General fault injection mechanism.
722 Format: <interval>,<probability>,<space>,<times>
723 See also /Documentation/fault-injection/.
726 See header of drivers/scsi/fd_mcs.c.
729 See header of drivers/scsi/fdomain.c.
732 See Documentation/floppy.txt.
734 force_pal_cache_flush
735 [IA-64] Avoid check_sal_cache_flush which may hang on
736 buggy SAL_CACHE_FLUSH implementations. Using this
737 parameter will force ia64_sal_cache_flush to call
738 ia64_pal_cache_flush instead of SAL_CACHE_FLUSH.
741 [HW,JOY] Multisystem joystick and NES/SNES/PSX pad
742 support via parallel port (up to 5 devices per port)
743 Format: <port#>,<pad1>,<pad2>,<pad3>,<pad4>,<pad5>
744 See also Documentation/input/joystick-parport.txt
748 gart_fix_e820= [X86_64] disable the fix e820 for K8 GART
753 See header of drivers/scsi/gdth.c.
755 gpt [EFI] Forces disk with valid GPT signature but
756 invalid Protective MBR to be treated as GPT.
760 hashdist= [KNL,NUMA] Large hashes allocated during boot
761 are distributed across NUMA nodes. Defaults on
762 for IA-64, off otherwise.
763 Format: 0 | 1 (for off | on)
765 hcl= [IA-64] SGI's Hardware Graph compatibility layer
767 hd= [EIDE] (E)IDE hard drive subsystem geometry
768 Format: <cyl>,<head>,<sect>
770 highmem=nn[KMG] [KNL,BOOT] forces the highmem zone to have an exact
771 size of <nn>. This works even on boxes that have no
772 highmem otherwise. This also works to reduce highmem
773 size on bigger boxes.
775 highres= [KNL] Enable/disable high resolution timer mode.
776 Valid parameters: "on", "off"
780 See Documentation/isdn/README.HiSax.
782 hugepages= [HW,X86-32,IA-64] HugeTLB pages to allocate at boot.
783 hugepagesz= [HW,IA-64,PPC,X86-64] The size of the HugeTLB pages.
784 On x86-64 and powerpc, this option can be specified
785 multiple times interleaved with hugepages= to reserve
786 huge pages of different sizes. Valid pages sizes on
787 x86-64 are 2M (when the CPU supports "pse") and 1G
788 (when the CPU supports the "pdpe1gb" cpuinfo flag)
789 Note that 1GB pages can only be allocated at boot time
790 using hugepages= and not freed afterwards.
792 [same as hugepagesz=] The size of the default
793 HugeTLB page size. This is the size represented by
794 the legacy /proc/ hugepages APIs, used for SHM, and
795 default size when mounting hugetlbfs filesystems.
796 Defaults to the default architecture's huge page size
799 i8042.direct [HW] Put keyboard port into non-translated mode
800 i8042.dumbkbd [HW] Pretend that controller can only read data from
801 keyboard and cannot control its state
802 (Don't attempt to blink the leds)
803 i8042.noaux [HW] Don't check for auxiliary (== mouse) port
804 i8042.nokbd [HW] Don't check/create keyboard port
805 i8042.noloop [HW] Disable the AUX Loopback command while probing
807 i8042.nomux [HW] Don't check presence of an active multiplexing
809 i8042.nopnp [HW] Don't use ACPIPnP / PnPBIOS to discover KBD/AUX
812 [HW] Frequency with which keyboard LEDs should blink
813 when kernel panics (default is 0.5 sec)
814 i8042.reset [HW] Reset the controller during init and cleanup
815 i8042.unlock [HW] Unlock (ignore) the keylock
819 i8k.ignore_dmi [HW] Continue probing hardware even if DMI data
820 indicates that the driver is running on unsupported
822 i8k.force [HW] Activate i8k driver even if SMM BIOS signature
823 does not match list of supported models.
825 [HW] Report power status in /proc/i8k
826 (disabled by default)
827 i8k.restricted [HW] Allow controlling fans only if SYS_ADMIN
830 ibmmcascsi= [HW,MCA,SCSI] IBM MicroChannel SCSI adapter
831 See Documentation/mca.txt.
834 Format: <io>[,<membase>[,<icn_id>[,<icn_id2>]]]
836 ide= [HW] (E)IDE subsystem
837 Format: ide=nodma or ide=doubler
838 See Documentation/ide/ide.txt.
840 idebus= [HW] (E)IDE subsystem - VLB/PCI bus speed
841 See Documentation/ide/ide.txt.
844 Format: idle=poll or idle=mwait, idle=halt, idle=nomwait
845 Poll forces a polling idle loop that can slightly improves the performance
846 of waking up a idle CPU, but will use a lot of power and make the system
847 run hot. Not recommended.
848 idle=mwait. On systems which support MONITOR/MWAIT but the kernel chose
849 to not use it because it doesn't save as much power as a normal idle
850 loop use the MONITOR/MWAIT idle loop anyways. Performance should be the same
852 idle=halt. Halt is forced to be used for CPU idle.
853 In such case C2/C3 won't be used again.
854 idle=nomwait. Disable mwait for CPU C-states
856 ide-pci-generic.all-generic-ide [HW] (E)IDE subsystem
857 Claim all unknown PCI IDE storage controllers.
859 ignore_loglevel [KNL]
860 Ignore loglevel setting - this will print /all/
861 kernel messages to the console. Useful for debugging.
864 Set number of hash buckets for inode cache.
867 See header of drivers/scsi/in2000.c.
871 Run specified binary instead of /sbin/init as init
874 initcall_debug [KNL] Trace initcalls as they are executed. Useful
875 for working out where the kernel is dying during
878 initrd= [BOOT] Specify the location of the initial ramdisk
880 inport.irq= [HW] Inport (ATI XL and Microsoft) busmouse driver
898 intel_iommu= [DMAR] Intel IOMMU driver (DMAR) option
900 Disable intel iommu driver.
901 igfx_off [Default Off]
902 By default, gfx is mapped as normal device. If a gfx
903 device has a dedicated DMAR unit, the DMAR unit is
904 bypassed by not enabling DMAR with this option. In
905 this case, gfx device will use physical address for
908 With this option iommu will not optimize to look
909 for io virtual address below 32 bit forcing dual
910 address cycle on pci bus for cards supporting greater
911 than 32 bit addressing. The default is to look
912 for translation below 32 bit and if not available
913 then look in the higher range.
915 With this option on every unmap_single operation will
916 result in a hardware IOTLB flush operation as opposed
917 to batching them for performance.
919 io_delay= [X86-32,X86-64] I/O delay method
921 Standard port 0x80 based delay
923 Alternate port 0xed based delay (needed on some systems)
925 Simple two microseconds delay
929 io7= [HW] IO7 for Marvel based alpha systems
930 See comment before marvel_specify_io7 in
931 arch/alpha/kernel/core_marvel.c.
934 See Documentation/filesystems/nfsroot.txt.
936 ip2= [HW] Set IO/IRQ pairs for up to 4 IntelliPort boards
937 See comment before ip2_setup() in
938 drivers/char/ip2/ip2base.c.
940 ips= [HW,SCSI] Adaptec / IBM ServeRAID controller
941 See header of drivers/scsi/ips.c.
943 ports= [IP_VS_FTP] IPVS ftp helper module
945 Up to 8 (IP_VS_APP_MAX_PORTS) ports
947 Format: <port>,<port>....
950 When an interrupt is not handled search all handlers
951 for it. Intended to get systems with badly broken
955 When an interrupt is not handled search all handlers
956 for it. Also check all handlers each timer
957 interrupt. Intended to get systems with badly broken
961 Format: <RDP>,<reset>,<pci_scan>,<verbosity>
963 isolcpus= [KNL,SMP] Isolate CPUs from the general scheduler.
965 <cpu number>,...,<cpu number>
967 <cpu number>-<cpu number> (must be a positive range in ascending order)
969 <cpu number>,...,<cpu number>-<cpu number>
970 This option can be used to specify one or more CPUs
971 to isolate from the general SMP balancing and scheduling
972 algorithms. The only way to move a process onto or off
973 an "isolated" CPU is via the CPU affinity syscalls.
974 <cpu number> begins at 0 and the maximum value is
975 "number of CPUs in system - 1".
977 This option is the preferred way to isolate CPUs. The
978 alternative -- manually setting the CPU mask of all
979 tasks in the system -- can cause problems and
980 suboptimal load balancer performance.
984 js= [HW,JOY] Analog joystick
985 See Documentation/input/joystick.txt.
987 kernelcore=nn[KMG] [KNL,X86-32,IA-64,PPC,X86-64] This parameter
988 specifies the amount of memory usable by the kernel
989 for non-movable allocations. The requested amount is
990 spread evenly throughout all nodes in the system. The
991 remaining memory in each node is used for Movable
992 pages. In the event, a node is too small to have both
993 kernelcore and Movable pages, kernelcore pages will
994 take priority and other nodes will have a larger number
995 of kernelcore pages. The Movable zone is used for the
996 allocation of pages that may be reclaimed or moved
997 by the page migration subsystem. This means that
998 HugeTLB pages may not be allocated from this zone.
999 Note that allocations like PTEs-from-HighMem still
1000 use the HighMem zone if it exists, and the Normal
1001 zone if it does not.
1003 movablecore=nn[KMG] [KNL,X86-32,IA-64,PPC,X86-64] This parameter
1004 is similar to kernelcore except it specifies the
1005 amount of memory used for migratable allocations.
1006 If both kernelcore and movablecore is specified,
1007 then kernelcore will be at *least* the specified
1008 value but may be more. If movablecore on its own
1009 is specified, the administrator must be careful
1010 that the amount of memory usable for all allocations
1015 kstack=N [X86-32,X86-64] Print N words from the kernel stack
1018 kgdboc= [HW] kgdb over consoles.
1019 Requires a tty driver that supports console polling.
1020 (only serial suported for now)
1021 Format: <serial_device>[,baud]
1027 lapic [X86-32,APIC] Enable the local APIC even if BIOS
1030 lapic_timer_c2_ok [X86-32,x86-64,APIC] trust the local apic timer in
1033 libata.dma= [LIBATA] DMA control
1034 libata.dma=0 Disable all PATA and SATA DMA
1035 libata.dma=1 PATA and SATA Disk DMA only
1036 libata.dma=2 ATAPI (CDROM) DMA only
1037 libata.dma=4 Compact Flash DMA only
1038 Combinations also work, so libata.dma=3 enables DMA
1039 for disks and CDROMs, but not CFs.
1041 libata.noacpi [LIBATA] Disables use of ACPI in libata suspend/resume
1045 libata.force= [LIBATA] Force configurations. The format is comma
1046 separated list of "[ID:]VAL" where ID is
1047 PORT[:DEVICE]. PORT and DEVICE are decimal numbers
1048 matching port, link or device. Basically, it matches
1049 the ATA ID string printed on console by libata. If
1050 the whole ID part is omitted, the last PORT and DEVICE
1051 values are used. If ID hasn't been specified yet, the
1052 configuration applies to all ports, links and devices.
1054 If only DEVICE is omitted, the parameter applies to
1055 the port and all links and devices behind it. DEVICE
1056 number of 0 either selects the first device or the
1057 first fan-out link behind PMP device. It does not
1058 select the host link. DEVICE number of 15 selects the
1059 host link and device attached to it.
1061 The VAL specifies the configuration to force. As long
1062 as there's no ambiguity shortcut notation is allowed.
1063 For example, both 1.5 and 1.5G would work for 1.5Gbps.
1064 The following configurations can be forced.
1066 * Cable type: 40c, 80c, short40c, unk, ign or sata.
1067 Any ID with matching PORT is used.
1069 * SATA link speed limit: 1.5Gbps or 3.0Gbps.
1071 * Transfer mode: pio[0-7], mwdma[0-4] and udma[0-7].
1072 udma[/][16,25,33,44,66,100,133] notation is also
1075 * [no]ncq: Turn on or off NCQ.
1077 If there are multiple matching configurations changing
1078 the same attribute, the last one is used.
1080 load_ramdisk= [RAM] List of ramdisks to load from floppy
1081 See Documentation/ramdisk.txt.
1083 lockd.nlm_grace_period=P [NFS] Assign grace period.
1086 lockd.nlm_tcpport=N [NFS] Assign TCP port.
1089 lockd.nlm_timeout=T [NFS] Assign timeout value.
1092 lockd.nlm_udpport=M [NFS] Assign UDP port.
1095 logibm.irq= [HW,MOUSE] Logitech Bus Mouse Driver
1098 loglevel= All Kernel Messages with a loglevel smaller than the
1099 console loglevel will be printed to the console. It can
1100 also be changed with klogd or other programs. The
1101 loglevels are defined as follows:
1103 0 (KERN_EMERG) system is unusable
1104 1 (KERN_ALERT) action must be taken immediately
1105 2 (KERN_CRIT) critical conditions
1106 3 (KERN_ERR) error conditions
1107 4 (KERN_WARNING) warning conditions
1108 5 (KERN_NOTICE) normal but significant condition
1109 6 (KERN_INFO) informational
1110 7 (KERN_DEBUG) debug-level messages
1112 log_buf_len=n Sets the size of the printk ring buffer, in bytes.
1113 Format: { n | nk | nM }
1114 n must be a power of two. The default size
1115 is set in the kernel config file.
1117 logo.nologo [FB] Disables display of the built-in Linux logo.
1118 This may be used to provide more screen space for
1119 kernel log messages and is useful when debugging
1120 kernel boot problems.
1122 lp=0 [LP] Specify parallel ports to use, e.g,
1123 lp=port[,port...] lp=none,parport0 (lp0 not configured, lp1 uses
1124 lp=reset first parallel port). 'lp=0' disables the
1125 lp=auto printer driver. 'lp=reset' (which can be
1126 specified in addition to the ports) causes
1127 attached printers to be reset. Using
1128 lp=port1,port2,... specifies the parallel ports
1129 to associate lp devices with, starting with
1130 lp0. A port specification may be 'none' to skip
1131 that lp device, or a parport name such as
1132 'parport0'. Specifying 'lp=auto' instead of a
1133 port specification list means that device IDs
1134 from each port should be examined, to see if
1135 an IEEE 1284-compliant printer is attached; if
1136 so, the driver will manage that printer.
1137 See also header of drivers/char/lp.c.
1140 Sets loops_per_jiffy to given constant, thus avoiding
1141 time-consuming boot-time autodetection (up to 250 ms per
1142 CPU). 0 enables autodetection (default). To determine
1143 the correct value for your kernel, boot with normal
1144 autodetection and see what value is printed. Note that
1145 on SMP systems the preset will be applied to all CPUs,
1146 which is likely to cause problems if your CPUs need
1147 significantly divergent settings. An incorrect value
1148 will cause delays in the kernel to be wrong, leading to
1149 unpredictable I/O errors and other breakage. Although
1150 unlikely, in the extreme case this might damage your
1154 Format: <io>,<irq>,<dma>
1156 mac5380= [HW,SCSI] Format:
1157 <can_queue>,<cmd_per_lun>,<sg_tablesize>,<hostid>,<use_tags>
1159 machvec= [IA64] Force the use of a particular machine-vector
1160 (machvec) in a generic kernel.
1161 Example: machvec=hpzx1_swiotlb
1163 max_loop= [LOOP] Maximum number of loopback devices that can
1167 maxcpus= [SMP] Maximum number of processors that an SMP kernel
1168 should make use of. maxcpus=n : n >= 0 limits the
1169 kernel to using 'n' processors. n=0 is a special case,
1170 it is equivalent to "nosmp", which also disables
1173 max_addr=[KMG] [KNL,BOOT,ia64] All physical memory greater than or
1174 equal to this physical address is ignored.
1176 max_luns= [SCSI] Maximum number of LUNs to probe.
1177 Should be between 1 and 2^32-1.
1180 [SCSI] Maximum number of LUNs received.
1181 Should be between 1 and 16384.
1185 mce [X86-32] Machine Check Exception
1187 mce=option [X86-64] See Documentation/x86_64/boot-options.txt
1189 md= [HW] RAID subsystems devices and level
1190 See Documentation/md.txt.
1193 Format: <first>,<last>
1194 Specifies range of consoles to be captured by the MDA.
1196 mem=nn[KMG] [KNL,BOOT] Force usage of a specific amount of memory
1197 Amount of memory to be used when the kernel is not able
1198 to see the whole system memory or for test.
1199 [X86-32] Use together with memmap= to avoid physical
1200 address space collisions. Without memmap= PCI devices
1201 could be placed at addresses belonging to unused RAM.
1203 mem=nopentium [BUGS=X86-32] Disable usage of 4MB pages for kernel
1206 memmap=exactmap [KNL,X86-32,X86_64] Enable setting of an exact
1207 E820 memory map, as specified by the user.
1208 Such memmap=exactmap lines can be constructed based on
1209 BIOS output or other requirements. See the memmap=nn@ss
1212 memmap=nn[KMG]@ss[KMG]
1213 [KNL] Force usage of a specific region of memory
1214 Region of memory to be used, from ss to ss+nn.
1216 memmap=nn[KMG]#ss[KMG]
1217 [KNL,ACPI] Mark specific memory as ACPI data.
1218 Region of memory to be used, from ss to ss+nn.
1220 memmap=nn[KMG]$ss[KMG]
1221 [KNL,ACPI] Mark specific memory as reserved.
1222 Region of memory to be used, from ss to ss+nn.
1223 Example: Exclude memory from 0x18690000-0x1869ffff
1224 memmap=64K$0x18690000
1226 memmap=0x10000$0x18690000
1228 memtest= [KNL,X86] Enable memtest
1230 range: 0,4 : pattern number
1231 default : 0 <disable>
1233 meye.*= [HW] Set MotionEye Camera parameters
1234 See Documentation/video4linux/meye.txt.
1236 mfgpt_irq= [IA-32] Specify the IRQ to use for the
1237 Multi-Function General Purpose Timers on AMD Geode
1240 mfgptfix [X86-32] Fix MFGPT timers on AMD Geode platforms when
1241 the BIOS has incorrectly applied a workaround. TinyBIOS
1242 version 0.98 is known to be affected, 0.99 fixes the
1243 problem by letting the user disable the workaround.
1248 [KNL] When CONFIG_DEBUG_MEMORY_INIT is set, this
1249 parameter allows control of the logging verbosity for
1250 the additional memory initialisation checks. A value
1251 of 0 disables mminit logging and a level of 4 will
1252 log everything. Information is printed at KERN_DEBUG
1253 so loglevel=8 may also need to be specified.
1256 [MOUSE] Maximum time between finger touching and
1257 leaving touchpad surface for touch to be considered
1258 a tap and be reported as a left button click (for
1259 touchpads working in absolute mode only).
1261 mousedev.xres= [MOUSE] Horizontal screen resolution, used for devices
1262 reporting absolute coordinates, such as tablets
1263 mousedev.yres= [MOUSE] Vertical screen resolution, used for devices
1264 reporting absolute coordinates, such as tablets
1269 MTD_Partition= [MTD]
1270 Format: <name>,<region-number>,<size>,<offset>
1272 MTD_Region= [MTD] Format:
1273 <name>,<region-number>[,<base>,<size>,<buswidth>,<altbuswidth>]
1276 See drivers/mtd/cmdlinepart.c.
1279 ARM/S3C2412 JIVE boot control
1281 See arch/arm/mach-s3c2412/mach-jive.c
1283 mtouchusb.raw_coordinates=
1284 [HW] Make the MicroTouch USB driver use raw coordinates
1285 ('y', default) or cooked coordinates ('n')
1287 n2= [NET] SDL Inc. RISCom/N2 synchronous serial card
1290 See header of drivers/scsi/NCR_D700.c.
1294 ncr53c400= [HW,SCSI]
1296 ncr53c400a= [HW,SCSI]
1298 ncr53c406a= [HW,SCSI]
1300 ncr53c8xx= [HW,SCSI]
1302 netdev= [NET] Network devices parameters
1303 Format: <irq>,<io>,<mem_start>,<mem_end>,<name>
1304 Note that mem_start is often overloaded to mean
1305 something different and driver-specific.
1306 This usage is only documented in each driver source
1310 [NETFILTER] Enable connection tracking flow accounting
1311 0 to disable accounting
1312 1 to enable accounting
1313 Default value depends on CONFIG_NF_CT_ACCT that is
1314 going to be removed in 2.6.29.
1317 See Documentation/filesystems/nfsroot.txt.
1319 nfsroot= [NFS] nfs root filesystem for disk-less boxes.
1320 See Documentation/filesystems/nfsroot.txt.
1322 nfs.callback_tcpport=
1323 [NFS] set the TCP port on which the NFSv4 callback
1324 channel should listen.
1326 nfs.idmap_cache_timeout=
1327 [NFS] set the maximum lifetime for idmapper cache
1331 [NFS] enable 64-bit inode numbers.
1332 If zero, the NFS client will fake up a 32-bit inode
1333 number for the readdir() and stat() syscalls instead
1334 of returning the full 64-bit number.
1335 The default is to return 64-bit inode numbers.
1337 nmi_debug= [KNL,AVR32] Specify one or more actions to take
1338 when a NMI is triggered.
1339 Format: [state][,regs][,debounce][,die]
1341 nmi_watchdog= [KNL,BUGS=X86-32] Debugging features for SMP kernels
1343 no387 [BUGS=X86-32] Tells the kernel to use the 387 maths
1344 emulation library even if a 387 maths coprocessor
1347 noaliencache [MM, NUMA, SLAB] Disables the allocation of alien
1348 caches in the slab allocator. Saves per-node memory,
1349 but will impact performance.
1353 noapic [SMP,APIC] Tells the kernel to not make use of any
1354 IOAPICs that may be present in the system.
1356 nobats [PPC] Do not use BATs for mapping kernel lowmem
1357 on "Classic" PPC cores.
1361 nodelayacct [KNL] Disable per-task delay accounting
1363 nodisconnect [HW,SCSI,M68K] Disables SCSI disconnects.
1365 noefi [X86-32,X86-64] Disable EFI runtime services support.
1369 noexec [X86-32,X86-64]
1370 On X86-32 available only on PAE configured kernels.
1371 noexec=on: enable non-executable mappings (default)
1372 noexec=off: disable non-executable mappings
1375 This affects only 32-bit executables.
1376 noexec32=on: enable non-executable mappings (default)
1377 read doesn't imply executable mappings
1378 noexec32=off: disable non-executable mappings
1379 read implies executable mappings
1381 nofxsr [BUGS=X86-32] Disables x86 floating point extended
1382 register save and restore. The kernel will only save
1383 legacy floating-point registers on task switch.
1385 noclflush [BUGS=X86] Don't use the CLFLUSH instruction
1389 no-hlt [BUGS=X86-32] Tells the kernel that the hlt
1390 instruction doesn't work correctly and not to
1393 nohalt [IA-64] Tells the kernel not to use the power saving
1394 function PAL_HALT_LIGHT when idle. This increases
1395 power-consumption. On the positive side, it reduces
1396 interrupt wake-up latency, which may improve performance
1397 in certain environments such as networked servers or
1400 nohz= [KNL] Boottime enable/disable dynamic ticks
1401 Valid arguments: on, off
1404 noirqbalance [X86-32,SMP,KNL] Disable kernel irq balancing
1406 noirqdebug [X86-32] Disables the code which attempts to detect and
1407 disable unhandled interrupt sources.
1409 no_timer_check [X86-32,X86_64,APIC] Disables the code which tests for
1410 broken timer IRQ sources.
1412 noisapnp [ISAPNP] Disables ISA PnP code.
1414 noinitrd [RAM] Tells the kernel not to load any configured
1419 nojitter [IA64] Disables jitter checking for ITC timers.
1421 nolapic [X86-32,APIC] Do not enable or use the local APIC.
1423 nolapic_timer [X86-32,APIC] Do not use the local APIC timer.
1425 noltlbs [PPC] Do not use large page/tlb entries for kernel
1426 lowmem mapping on PPC40x.
1428 nomca [IA-64] Disable machine check abort handling
1430 nomce [X86-32] Machine Check Exception
1432 nomfgpt [X86-32] Disable Multi-Function General Purpose
1433 Timer usage (for AMD Geode machines).
1435 noreplace-paravirt [X86-32,PV_OPS] Don't patch paravirt_ops
1437 noreplace-smp [X86-32,SMP] Don't replace SMP instructions
1438 with UP alternatives
1440 noresidual [PPC] Don't use residual data on PReP machines.
1442 noresume [SWSUSP] Disables resume and restores original swap
1445 no-scroll [VGA] Disables scrollback.
1446 This is required for the Braillex ib80-piezo Braille
1447 reader made by F.H. Papenmeier (Germany).
1451 nosep [BUGS=X86-32] Disables x86 SYSENTER/SYSEXIT support.
1453 nosmp [SMP] Tells an SMP kernel to act as a UP kernel,
1454 and disable the IO APIC. legacy for "maxcpus=0".
1456 nosoftlockup [KNL] Disable the soft-lockup detector.
1458 nosync [HW,M68K] Disables sync negotiation for all devices.
1460 notsc [BUGS=X86-32] Disable Time Stamp Counter
1462 nousb [USB] Disable the USB subsystem
1466 nptcg= [IA64] Override max number of concurrent global TLB
1467 purges which is reported from either PAL_VM_SUMMARY or
1470 numa_zonelist_order= [KNL, BOOT] Select zonelist order for NUMA.
1471 one of ['zone', 'node', 'default'] can be specified
1472 This can be set from sysctl after boot.
1473 See Documentation/sysctl/vm.txt for details.
1475 nr_uarts= [SERIAL] maximum number of UARTs to be registered.
1477 olpc_ec_timeout= [OLPC] ms delay when issuing EC commands
1478 Rather than timing out after 20 ms if an EC
1479 command is not properly ACKed, override the length
1480 of the timeout. We have interrupts disabled while
1481 waiting for the ACK, so if this is set too high
1482 interrupts *may* be lost!
1487 oprofile.timer= [HW]
1488 Use timer interrupt instead of performance counters
1490 osst= [HW,SCSI] SCSI Tape Driver
1491 Format: <buffer_size>,<write_threshold>
1492 See also Documentation/scsi/st.txt.
1494 panic= [KNL] Kernel behaviour on panic
1497 parkbd.port= [HW] Parallel port number the keyboard adapter is
1498 connected to, default is 0.
1500 parkbd.mode= [HW] Parallel port keyboard adapter mode of operation,
1501 0 for XT, 1 for AT (default is AT).
1504 parport= [HW,PPT] Specify parallel ports. 0 disables.
1505 Format: { 0 | auto | 0xBBB[,IRQ[,DMA]] }
1506 Use 'auto' to force the driver to use any
1507 IRQ/DMA settings detected (the default is to
1508 ignore detected IRQ/DMA settings because of
1509 possible conflicts). You can specify the base
1510 address, IRQ, and DMA settings; IRQ and DMA
1511 should be numbers, or 'auto' (for using detected
1512 settings on that particular port), or 'nofifo'
1513 (to avoid using a FIFO even if it is detected).
1514 Parallel ports are assigned in the order they
1515 are specified on the command line, starting
1518 parport_init_mode= [HW,PPT]
1519 Configure VIA parallel port to operate in
1520 a specific mode. This is necessary on Pegasos
1521 computer where firmware has no options for setting
1522 up parallel port mode and sets it to spp.
1523 Currently this function knows 686a and 8231 chips.
1524 Format: [spp|ps2|epp|ecp|ecpepp]
1526 pas2= [HW,OSS] Format:
1527 <io>,<irq>,<dma>,<dma16>,<sb_io>,<sb_irq>,<sb_dma>,<sb_dma16>
1530 See header of drivers/scsi/pas16.c.
1533 Halt all CPUs after the first oops has been printed for
1534 the specified number of seconds. This is to be used if
1535 your oopses keep scrolling off the screen.
1540 See header of drivers/block/paride/pcd.c.
1541 See also Documentation/paride.txt.
1543 pci=option[,option...] [PCI] various PCI subsystem options:
1544 off [X86-32] don't probe for the PCI bus
1545 bios [X86-32] force use of PCI BIOS, don't access
1546 the hardware directly. Use this if your machine
1547 has a non-standard PCI host bridge.
1548 nobios [X86-32] disallow use of PCI BIOS, only direct
1549 hardware access methods are allowed. Use this
1550 if you experience crashes upon bootup and you
1551 suspect they are caused by the BIOS.
1552 conf1 [X86-32] Force use of PCI Configuration
1554 conf2 [X86-32] Force use of PCI Configuration
1556 noaer [PCIE] If the PCIEAER kernel config parameter is
1557 enabled, this kernel boot option can be used to
1558 disable the use of PCIE advanced error reporting.
1559 nodomains [PCI] Disable support for multiple PCI
1560 root domains (aka PCI segments, in ACPI-speak).
1561 nommconf [X86-32,X86_64] Disable use of MMCONFIG for PCI
1563 nomsi [MSI] If the PCI_MSI kernel config parameter is
1564 enabled, this kernel boot option can be used to
1565 disable the use of MSI interrupts system-wide.
1566 biosirq [X86-32] Use PCI BIOS calls to get the interrupt
1567 routing table. These calls are known to be buggy
1568 on several machines and they hang the machine
1569 when used, but on other computers it's the only
1570 way to get the interrupt routing table. Try
1571 this option if the kernel is unable to allocate
1572 IRQs or discover secondary PCI buses on your
1574 rom [X86-32] Assign address space to expansion ROMs.
1575 Use with caution as certain devices share
1576 address decoders between ROMs and other
1578 norom [X86-32,X86_64] Do not assign address space to
1579 expansion ROMs that do not already have
1580 BIOS assigned address ranges.
1581 irqmask=0xMMMM [X86-32] Set a bit mask of IRQs allowed to be
1582 assigned automatically to PCI devices. You can
1583 make the kernel exclude IRQs of your ISA cards
1585 pirqaddr=0xAAAAA [X86-32] Specify the physical address
1586 of the PIRQ table (normally generated
1587 by the BIOS) if it is outside the
1588 F0000h-100000h range.
1589 lastbus=N [X86-32] Scan all buses thru bus #N. Can be
1590 useful if the kernel is unable to find your
1591 secondary buses and you want to tell it
1592 explicitly which ones they are.
1593 assign-busses [X86-32] Always assign all PCI bus
1594 numbers ourselves, overriding
1595 whatever the firmware may have done.
1596 usepirqmask [X86-32] Honor the possible IRQ mask stored
1597 in the BIOS $PIR table. This is needed on
1598 some systems with broken BIOSes, notably
1599 some HP Pavilion N5400 and Omnibook XE3
1600 notebooks. This will have no effect if ACPI
1601 IRQ routing is enabled.
1602 noacpi [X86-32] Do not use ACPI for IRQ routing
1603 or for PCI scanning.
1604 use_crs [X86-32] Use _CRS for PCI resource
1606 routeirq Do IRQ routing for all PCI devices.
1607 This is normally done in pci_enable_device(),
1608 so this option is a temporary workaround
1609 for broken drivers that don't call it.
1610 skip_isa_align [X86] do not align io start addr, so can
1611 handle more pci cards
1612 firmware [ARM] Do not re-enumerate the bus but instead
1613 just use the configuration from the
1614 bootloader. This is currently used on
1615 IXP2000 systems where the bus has to be
1616 configured a certain way for adjunct CPUs.
1617 noearly [X86] Don't do any early type 1 scanning.
1618 This might help on some broken boards which
1619 machine check when some devices' config space
1620 is read. But various workarounds are disabled
1621 and some IOMMU drivers will not work.
1622 bfsort Sort PCI devices into breadth-first order.
1623 This sorting is done to get a device
1624 order compatible with older (<= 2.4) kernels.
1625 nobfsort Don't sort PCI devices into breadth-first order.
1626 cbiosize=nn[KMG] The fixed amount of bus space which is
1627 reserved for the CardBus bridge's IO window.
1628 The default value is 256 bytes.
1629 cbmemsize=nn[KMG] The fixed amount of bus space which is
1630 reserved for the CardBus bridge's memory
1631 window. The default value is 64 megabytes.
1633 pcmv= [HW,PCMCIA] BadgePAD 4
1636 See Documentation/paride.txt.
1638 pdcchassis= [PARISC,HW] Disable/Enable PDC Chassis Status codes at
1641 See arch/parisc/kernel/pdc_chassis.c
1644 See Documentation/paride.txt.
1647 See Documentation/paride.txt.
1649 pirq= [SMP,APIC] Manual mp-table setup
1650 See Documentation/i386/IO-APIC.txt.
1652 plip= [PPT,NET] Parallel port network link
1653 Format: { parport<nr> | timid | 0 }
1654 See also Documentation/parport.txt.
1656 pmtmr= [X86] Manual setup of pmtmr I/O Port.
1657 Override pmtimer IOPort with a hex value.
1664 { on | off | curr | res | no-curr | no-res }
1667 [ISAPNP] Exclude IRQs for the autoconfiguration
1670 [ISAPNP] Exclude DMAs for the autoconfiguration
1672 pnp_reserve_io= [ISAPNP] Exclude I/O ports for the autoconfiguration
1673 Ranges are in pairs (I/O port base and size).
1676 [ISAPNP] Exclude memory regions for the
1678 Ranges are in pairs (memory base and size).
1680 print-fatal-signals=
1681 [KNL] debug: print fatal signals
1682 print-fatal-signals=1: print segfault info to
1686 printk.time= Show timing data prefixed to each printk message line
1687 Format: <bool> (1/Y/y=enable, 0/N/n=disable)
1689 profile= [KNL] Enable kernel profiling via /proc/profile
1690 Format: [schedule,]<number>
1691 Param: "schedule" - profile schedule points.
1692 Param: <number> - step/bucket size as a power of 2 for
1693 statistical time based profiling.
1694 Param: "sleep" - profile D-state sleeping (millisecs).
1695 Requires CONFIG_SCHEDSTATS
1696 Param: "kvm" - profile VM exits.
1698 processor.max_cstate= [HW,ACPI]
1699 Limit processor to maximum C-state
1700 max_cstate=9 overrides any DMI blacklist limit.
1702 processor.nocst [HW,ACPI]
1703 Ignore the _CST method to determine C-states,
1704 instead using the legacy FADT method
1706 prompt_ramdisk= [RAM] List of RAM disks to prompt for floppy disk
1708 See Documentation/ramdisk.txt.
1710 psmouse.proto= [HW,MOUSE] Highest PS2 mouse protocol extension to
1711 probe for; one of (bare|imps|exps|lifebook|any).
1712 psmouse.rate= [HW,MOUSE] Set desired mouse report rate, in reports
1714 psmouse.resetafter= [HW,MOUSE]
1715 Try to reset the device after so many bad packets
1718 [HW,MOUSE] Set desired mouse resolution, in dpi.
1719 psmouse.smartscroll=
1720 [HW,MOUSE] Controls Logitech smartscroll autorepeat.
1721 0 = disabled, 1 = enabled (default).
1723 pss= [HW,OSS] Personal Sound System (ECHO ESC614)
1725 <io>,<mss_io>,<mss_irq>,<mss_dma>,<mpu_io>,<mpu_irq>
1728 See Documentation/paride.txt.
1731 [KNL] Number of legacy pty's. Overwrites compiled-in
1734 quiet [KNL] Disable most log messages
1739 See Documentation/md.txt.
1741 ramdisk_blocksize= [RAM]
1742 See Documentation/ramdisk.txt.
1744 ramdisk_size= [RAM] Sizes of RAM disks in kilobytes
1745 See Documentation/ramdisk.txt.
1747 rcupdate.blimit= [KNL,BOOT]
1748 Set maximum number of finished RCU callbacks to process
1751 rcupdate.qhimark= [KNL,BOOT]
1752 Set threshold of queued
1753 RCU callbacks over which batch limiting is disabled.
1755 rcupdate.qlowmark= [KNL,BOOT]
1756 Set threshold of queued RCU callbacks below which
1757 batch limiting is re-enabled.
1761 Run specified binary instead of /init from the ramdisk,
1762 used for early userspace startup. See initrd.
1764 reboot= [BUGS=X86-32,BUGS=ARM,BUGS=IA-64] Rebooting mode
1765 Format: <reboot_mode>[,<reboot_mode2>[,...]]
1766 See arch/*/kernel/reboot.c or arch/*/kernel/process.c
1769 [KNL, SMP] Set scheduler's default relax_domain_level.
1770 See Documentation/cpusets.txt.
1772 reserve= [KNL,BUGS] Force the kernel to ignore some iomem area
1774 reservetop= [X86-32]
1776 Reserves a hole at the top of the kernel virtual
1779 reset_devices [KNL] Force drivers to reset the underlying device
1780 during initialization.
1783 Specify the partition device for software suspend
1785 resume_offset= [SWSUSP]
1786 Specify the offset from the beginning of the partition
1787 given by "resume=" at which the swap header is located,
1788 in <PAGE_SIZE> units (needed only for swap files).
1789 See Documentation/power/swsusp-and-swap-files.txt
1791 retain_initrd [RAM] Keep initrd memory after extraction
1793 rhash_entries= [KNL,NET]
1794 Set number of hash buckets for route cache
1796 riscom8= [HW,SERIAL]
1797 Format: <io_board1>[,<io_board2>[,...<io_boardN>]]
1799 ro [KNL] Mount root device read-only on boot
1801 root= [KNL] Root filesystem
1803 rootdelay= [KNL] Delay (in seconds) to pause before attempting to
1804 mount the root filesystem
1806 rootflags= [KNL] Set root filesystem mount option string
1808 rootfstype= [KNL] Set root filesystem type
1810 rootwait [KNL] Wait (indefinitely) for root device to show up.
1811 Useful for devices that are detected asynchronously
1812 (e.g. USB and MMC devices).
1814 root_plug.vendor_id=
1815 [ROOTPLUG] Override the default vendor ID
1817 root_plug.product_id=
1818 [ROOTPLUG] Override the default product ID
1821 [ROOTPLUG] Enable debugging output
1823 rw [KNL] Mount root device read-write on boot
1825 S [KNL] Run init in single mode
1828 See drivers/net/irda/sa1100_ir.c.
1830 sbni= [NET] Granch SBNI12 leased line adapter
1832 sc1200wdt= [HW,WDT] SC1200 WDT (watchdog) driver
1833 Format: <io>[,<timeout>[,<isapnp>]]
1835 scsi_debug_*= [SCSI]
1836 See drivers/scsi/scsi_debug.c.
1838 scsi_default_dev_flags=
1839 [SCSI] SCSI default device flags
1842 scsi_dev_flags= [SCSI] Black/white list entry for vendor and model
1843 Format: <vendor>:<model>:<flags>
1844 (flags are integer value)
1846 scsi_logging_level= [SCSI] a bit mask of logging levels
1847 See drivers/scsi/scsi_logging.h for bits. Also
1848 settable via sysctl at dev.scsi.logging_level
1849 (/proc/sys/dev/scsi/logging_level).
1850 There is also a nice 'scsi_logging_level' script in the
1851 S390-tools package, available for download at
1852 http://www-128.ibm.com/developerworks/linux/linux390/s390-tools-1.5.4.html
1854 scsi_mod.scan= [SCSI] sync (default) scans SCSI busses as they are
1855 discovered. async scans them in kernel threads,
1856 allowing boot to proceed. none ignores them, expecting
1857 user space to do the scan.
1859 selinux [SELINUX] Disable or enable SELinux at boot time.
1860 Format: { "0" | "1" }
1861 See security/selinux/Kconfig help text.
1864 Default value is set via kernel config option.
1865 If enabled at boot time, /selinux/disable can be used
1866 later to disable prior to initial policy load.
1868 selinux_compat_net =
1869 [SELINUX] Set initial selinux_compat_net flag value.
1870 Format: { "0" | "1" }
1871 0 -- use new secmark-based packet controls
1872 1 -- use legacy packet controls
1873 Default value is 0 (preferred).
1874 Value can be changed at runtime via
1875 /selinux/compat_net.
1877 serialnumber [BUGS=X86-32]
1880 Maximal number of shapers.
1883 See header of drivers/scsi/sim710.c.
1890 slub_debug[=options[,slabs]] [MM, SLUB]
1891 Enabling slub_debug allows one to determine the
1892 culprit if slab objects become corrupted. Enabling
1893 slub_debug can create guard zones around objects and
1894 may poison objects when not in use. Also tracks the
1895 last alloc / free. For more information see
1896 Documentation/vm/slub.txt.
1898 slub_max_order= [MM, SLUB]
1899 Determines the maximum allowed order for slabs.
1900 A high setting may cause OOMs due to memory
1901 fragmentation. For more information see
1902 Documentation/vm/slub.txt.
1904 slub_min_objects= [MM, SLUB]
1905 The minimum number of objects per slab. SLUB will
1906 increase the slab order up to slub_max_order to
1907 generate a sufficiently large slab able to contain
1908 the number of objects indicated. The higher the number
1909 of objects the smaller the overhead of tracking slabs
1910 and the less frequently locks need to be acquired.
1911 For more information see Documentation/vm/slub.txt.
1913 slub_min_order= [MM, SLUB]
1914 Determines the mininum page order for slabs. Must be
1915 lower than slub_max_order.
1916 For more information see Documentation/vm/slub.txt.
1918 slub_nomerge [MM, SLUB]
1919 Disable merging of slabs with similar size. May be
1920 necessary if there is some reason to distinguish
1921 allocs to different slabs. Debug options disable
1922 merging on their own.
1923 For more information see Documentation/vm/slub.txt.
1926 Format: <io1>[,<io2>[,...,<io8>]]
1928 smp-alt-once [X86-32,SMP] On a hotplug CPU system, only
1929 attempt to substitute SMP alternatives once at boot.
1931 smsc-ircc2.nopnp [HW] Don't use PNP to discover SMC devices
1932 smsc-ircc2.ircc_cfg= [HW] Device configuration I/O port
1933 smsc-ircc2.ircc_sir= [HW] SIR base I/O port
1934 smsc-ircc2.ircc_fir= [HW] FIR base I/O port
1935 smsc-ircc2.ircc_irq= [HW] IRQ line
1936 smsc-ircc2.ircc_dma= [HW] DMA channel
1937 smsc-ircc2.ircc_transceiver= [HW] Transceiver type:
1938 0: Toshiba Satellite 1800 (GP data pin select)
1939 1: Fast pin select (default)
1942 snd-ad1816a= [HW,ALSA]
1944 snd-ad1848= [HW,ALSA]
1946 snd-ali5451= [HW,ALSA]
1948 snd-als100= [HW,ALSA]
1950 snd-als4000= [HW,ALSA]
1952 snd-azt2320= [HW,ALSA]
1954 snd-cmi8330= [HW,ALSA]
1956 snd-cmipci= [HW,ALSA]
1958 snd-cs4231= [HW,ALSA]
1960 snd-cs4232= [HW,ALSA]
1962 snd-cs4236= [HW,ALSA]
1964 snd-cs4281= [HW,ALSA]
1966 snd-cs46xx= [HW,ALSA]
1968 snd-dt019x= [HW,ALSA]
1970 snd-dummy= [HW,ALSA]
1972 snd-emu10k1= [HW,ALSA]
1974 snd-ens1370= [HW,ALSA]
1976 snd-ens1371= [HW,ALSA]
1978 snd-es968= [HW,ALSA]
1980 snd-es1688= [HW,ALSA]
1982 snd-es18xx= [HW,ALSA]
1984 snd-es1938= [HW,ALSA]
1986 snd-es1968= [HW,ALSA]
1988 snd-fm801= [HW,ALSA]
1990 snd-gusclassic= [HW,ALSA]
1992 snd-gusextreme= [HW,ALSA]
1994 snd-gusmax= [HW,ALSA]
1998 snd-ice1712= [HW,ALSA]
2000 snd-intel8x0= [HW,ALSA]
2002 snd-interwave= [HW,ALSA]
2007 snd-korg1212= [HW,ALSA]
2009 snd-maestro3= [HW,ALSA]
2011 snd-mpu401= [HW,ALSA]
2013 snd-mtpav= [HW,ALSA]
2015 snd-nm256= [HW,ALSA]
2017 snd-opl3sa2= [HW,ALSA]
2025 snd-opti93x= [HW,ALSA]
2029 snd-rme32= [HW,ALSA]
2031 snd-rme96= [HW,ALSA]
2033 snd-rme9652= [HW,ALSA]
2039 snd-sbawe= [HW,ALSA]
2041 snd-serial= [HW,ALSA]
2043 snd-sgalaxy= [HW,ALSA]
2045 snd-sonicvibes= [HW,ALSA]
2050 snd-sun-cs4231= [HW,ALSA]
2052 snd-trident= [HW,ALSA]
2054 snd-usb-audio= [HW,ALSA,USB]
2056 snd-via82xx= [HW,ALSA]
2058 snd-virmidi= [HW,ALSA]
2060 snd-wavefront= [HW,ALSA]
2062 snd-ymfpci= [HW,ALSA]
2065 [KNL] Should the soft-lockup detector generate panics.
2067 sonypi.*= [HW] Sony Programmable I/O Control Device driver
2068 See Documentation/sonypi.txt
2070 specialix= [HW,SERIAL] Specialix multi-serial port adapter
2071 See Documentation/specialix.txt.
2073 spia_io_base= [HW,MTD]
2079 Format: <io>,<irq>,<dma>,<mpu_io>,<mpu_irq>
2081 st= [HW,SCSI] SCSI tape parameters (buffers, etc.)
2082 See Documentation/scsi/st.txt.
2086 Set the STI (builtin display/keyboard on the HP-PARISC
2087 machines) console (graphic card) which should be used
2088 as the initial boot-console.
2089 See also comment in drivers/video/console/sticore.c.
2092 See comment in drivers/video/console/sticore.c.
2095 Format: bpp:<bpp1>[:<bpp2>[:<bpp3>...]]
2099 Control how the NFS server code allocates CPUs to
2100 service thread pools. Depending on how many NICs
2101 you have and where their interrupts are bound, this
2102 option will affect which CPUs will do NFS serving.
2103 Note: this parameter cannot be changed while the
2104 NFS server is running.
2106 auto the server chooses an appropriate mode
2107 automatically using heuristics
2108 global a single global pool contains all CPUs
2109 percpu one pool for each CPU
2110 pernode one pool for each NUMA node (equivalent
2111 to global on non-NUMA machines)
2113 swiotlb= [IA-64] Number of I/O TLB slabs
2117 sym53c416= [HW,SCSI]
2118 See header of drivers/scsi/sym53c416.c.
2120 sysrq_always_enabled
2122 Ignore sysrq setting - this boot parameter will
2123 neutralize any effect of /proc/sys/kernel/sysrq.
2124 Useful for debugging.
2127 See header of drivers/scsi/t128.c.
2131 test_suspend= [SUSPEND]
2132 Specify "mem" (for Suspend-to-RAM) or "standby" (for
2133 standby suspend) as the system sleep state to briefly
2134 enter during system startup. The system is woken from
2135 this state using a wakeup-capable RTC alarm.
2137 thash_entries= [KNL,NET]
2138 Set number of hash buckets for TCP connection
2140 thermal.act= [HW,ACPI]
2141 -1: disable all active trip points in all thermal zones
2142 <degrees C>: override all lowest active trip points
2144 thermal.crt= [HW,ACPI]
2145 -1: disable all critical trip points in all thermal zones
2146 <degrees C>: lower all critical trip points
2148 thermal.nocrt= [HW,ACPI]
2149 Set to disable actions on ACPI thermal zone
2150 critical and hot trip points.
2152 thermal.off= [HW,ACPI]
2153 1: disable ACPI thermal control
2155 thermal.psv= [HW,ACPI]
2156 -1: disable all passive trip points
2157 <degrees C>: override all passive trip points to this value
2159 thermal.tzp= [HW,ACPI]
2160 Specify global default ACPI thermal zone polling rate
2161 <deci-seconds>: poll all this frequency
2162 0: no polling (default)
2165 See comment before function dc390_setup() in
2166 drivers/scsi/tmscsim.c.
2170 trix= [HW,OSS] MediaTrix AudioTrix Pro
2172 <io>,<irq>,<dma>,<dma2>,<sb_io>,<sb_irq>,<sb_dma>,<mpu_io>,<mpu_irq>
2174 turbografx.map[2|3]= [HW,JOY]
2175 TurboGraFX parallel port interface
2177 <port#>,<js1>,<js2>,<js3>,<js4>,<js5>,<js6>,<js7>
2178 See also Documentation/input/joystick-parport.txt
2180 u14-34f= [HW,SCSI] UltraStor 14F/34F SCSI host adapter
2181 See header of drivers/scsi/u14-34f.c.
2190 [USB] Ignore overcurrent events (default N).
2191 Some badly-designed motherboards generate lots of
2192 bogus events, for ports that aren't wired to
2193 anything. Set this parameter to avoid log spamming.
2194 Note that genuine overcurrent events won't be
2199 Set unknown_nmi_panic=1 early on boot.
2201 usbcore.autosuspend=
2202 [USB] The autosuspend time delay (in seconds) used
2203 for newly-detected USB devices (default 2). This
2204 is the time required before an idle device will be
2205 autosuspended. Devices for which the delay is set
2206 to a negative value won't be autosuspended at all.
2209 [USBHID] The interval which mice are to be polled at.
2211 add_efi_memmap [EFI; x86-32,X86-64] Include EFI memory map in
2212 kernel's map of available physical RAM.
2214 vdso= [X86-32,SH,x86-64]
2215 vdso=2: enable compat VDSO (default with COMPAT_VDSO)
2216 vdso=1: enable VDSO (default)
2217 vdso=0: disable VDSO mapping
2219 vdso32= [X86-32,X86-64]
2220 vdso32=2: enable compat VDSO (default with COMPAT_VDSO)
2221 vdso32=1: enable 32-bit VDSO (default)
2222 vdso32=0: disable 32-bit VDSO mapping
2225 vector=percpu: enable percpu vector domain
2227 video= [FB] Frame buffer configuration
2228 See Documentation/fb/modedb.txt.
2230 vga= [BOOT,X86-32] Select a particular video mode
2231 See Documentation/i386/boot.txt and
2232 Documentation/svga.txt.
2233 Use vga=ask for menu.
2234 This is actually a boot loader parameter; the value is
2235 passed to the kernel using a special protocol.
2237 vmalloc=nn[KMG] [KNL,BOOT] Forces the vmalloc area to have an exact
2238 size of <nn>. This can be used to increase the
2239 minimum size (128MB on x86). It can also be used to
2240 decrease the size and leave more room for directly
2243 vmhalt= [KNL,S390] Perform z/VM CP command after system halt.
2246 vmpanic= [KNL,S390] Perform z/VM CP command after kernel panic.
2249 vmpoff= [KNL,S390] Perform z/VM CP command after power off.
2252 waveartist= [HW,OSS]
2253 Format: <io>,<irq>,<dma>,<dma2>
2256 See header of drivers/scsi/wd33c93.c.
2259 See header of drivers/scsi/wd7000.c.
2262 See Documentation/watchdog/wdt.txt.
2264 xd= [HW,XT] Original XT pre-IDE (RLL encoded) disks.
2265 xd_geo= See header of drivers/block/xd.c.
2267 xirc2ps_cs= [NET,PCMCIA]
2269 <irq>,<irq_mask>,<io>,<full_duplex>,<do_sound>,<lockup_hack>[,<irq2>[,<irq3>[,<irq4>]]]
2271 norandmaps Don't use address space randomization
2272 Equivalent to echo 0 > /proc/sys/kernel/randomize_va_space
2274 ______________________________________________________________________
2278 Add documentation for ALSA options.
2279 Add more DRM drivers.
projects / linux-2.6 / blob