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
466 hpet= [X86-32,HPET] option to control HPET usage
467 Format: { enable (default) | disable | force }
468 disable: disable HPET and use PIT instead
469 force: allow force enabled of undocumented chips (ICH4,
472 com20020= [HW,NET] ARCnet - COM20020 chipset
474 <io>[,<irq>[,<nodeID>[,<backplane>[,<ckp>[,<timeout>]]]]]
476 com90io= [HW,NET] ARCnet - COM90xx chipset (IO-mapped buffers)
480 ARCnet - COM90xx chipset (memory-mapped buffers)
481 Format: <io>[,<irq>[,<memstart>]]
483 condev= [HW,S390] console device
486 console= [KNL] Output console device and options.
488 tty<n> Use the virtual console device <n>.
492 Use the specified serial port. The options are of
493 the form "bbbbpnf", where "bbbb" is the baud rate,
494 "p" is parity ("n", "o", or "e"), "n" is number of
495 bits, and "f" is flow control ("r" for RTS or
496 omit it). Default is "9600n8".
498 See Documentation/serial-console.txt for more
500 Documentation/networking/netconsole.txt for an
503 uart[8250],io,<addr>[,options]
504 uart[8250],mmio,<addr>[,options]
505 Start an early, polled-mode console on the 8250/16550
506 UART at the specified I/O port or MMIO address,
507 switching to the matching ttyS device later. The
508 options are the same as for ttyS, above.
510 If the device connected to the port is not a TTY but a braille
511 device, prepend "brl," before the device type, for instance
513 For now, only VisioBraille is supported.
515 earlycon= [KNL] Output early console device and options.
516 uart[8250],io,<addr>[,options]
517 uart[8250],mmio,<addr>[,options]
518 Start an early, polled-mode console on the 8250/16550
519 UART at the specified I/O port or MMIO address.
520 The options are the same as for ttyS, above.
523 [HW] Never suspend the console
524 Disable suspending of consoles during suspend and
525 hibernate operations. Once disabled, debugging
526 messages can reach various consoles while the rest
527 of the system is being put to sleep (ie, while
528 debugging driver suspend/resume hooks). This may
529 not work reliably with all consoles, but is known
530 to work with serial and VGA consoles.
532 cpcihp_generic= [HW,PCI] Generic port I/O CompactPCI driver
534 <first_slot>,<last_slot>,<port>,<enum_bit>[,<debug>]
536 crashkernel=nn[KMG]@ss[KMG]
537 [KNL] Reserve a chunk of physical memory to
538 hold a kernel to switch to with kexec on panic.
540 crashkernel=range1:size1[,range2:size2,...][@offset]
541 [KNL] Same as above, but depends on the memory
542 in the running system. The syntax of range is
543 start-[end] where start and end are both
544 a memory unit (amount[KMG]). See also
545 Documentation/kdump/kdump.txt for a example.
548 Format: <io>,<irq>,<dma>,<dma2>,<mpuio>,<mpuirq>
553 cs89x0_media= [HW,NET]
554 Format: { rj45 | aui | bnc }
557 See header of drivers/s390/block/dasd_devmap.c.
559 db9.dev[2|3]= [HW,JOY] Multisystem joystick support via parallel port
560 (one device per port)
561 Format: <port#>,<type>
562 See also Documentation/input/joystick-parport.txt
564 debug [KNL] Enable kernel debugging (events log level).
567 [KNL] verbose self-tests
569 Print debugging info while doing the locking API
571 We default to 0 (no extra messages), setting it to
572 1 will print _a lot_ more information - normally
573 only useful to kernel developers.
575 debug_objects [KNL] Enable object debugging
577 debugpat [X86] Enable PAT debugging
579 decnet.addr= [HW,NET]
580 Format: <area>[,<node>]
581 See also Documentation/networking/decnet.txt.
584 Format: <blue0>,<blue1>,<blue2>,...,<blue15>
585 Change the default blue palette of the console.
586 This is a 16-member array composed of values
590 Format: <green0>,<green1>,<green2>,...,<green15>
591 Change the default green palette of the console.
592 This is a 16-member array composed of values
596 Format: <red0>,<red1>,<red2>,...,<red15>
597 Change the default red palette of the console.
598 This is a 16-member array composed of values
604 Set system-wide default UTF-8 mode for all tty's.
605 Default is 1, i.e. UTF-8 mode is enabled for all
606 newly opened terminals.
609 Set number of hash buckets for dentry cache.
612 IO parameters + enable/disable command.
614 digiepca= [HW,SERIAL]
615 See drivers/char/README.epca and
616 Documentation/digiepca.txt.
618 disable_mtrr_cleanup [X86]
619 enable_mtrr_cleanup [X86]
620 The kernel tries to adjust MTRR layout from continuous
621 to discrete, to make X server driver able to add WB
622 entry later. This parameter enables/disables that.
624 mtrr_chunk_size=nn[KMG] [X86]
625 used for mtrr cleanup. It is largest continous chunk
626 that could hold holes aka. UC entries.
628 mtrr_gran_size=nn[KMG] [X86]
629 Used for mtrr cleanup. It is granularity of mtrr block.
631 Large value could prevent small alignment from
634 mtrr_spare_reg_nr=n [X86]
636 Range: 0,7 : spare reg number
638 Used for mtrr cleanup. It is spare mtrr entries number.
639 Set to 2 or more if your graphical card needs more.
641 disable_mtrr_trim [X86, Intel and AMD only]
642 By default the kernel will trim any uncacheable
643 memory out of your available memory pool based on
644 MTRR settings. This parameter disables that behavior,
645 possibly causing your machine to run very slowly.
647 dmasound= [HW,OSS] Sound subsystem buffers
653 earlyprintk= [X86-32,X86-64,SH,BLACKFIN]
655 earlyprintk=serial[,ttySn[,baudrate]]
657 Append ",keep" to not disable it when the real console
660 Only vga or serial at a time, not both.
662 Currently only ttyS0 and ttyS1 are supported.
664 Interaction with the standard serial driver is not
667 The VGA output is eventually overwritten by the real
673 Format: {"off" | "on" | "skip[mbr]"}
675 eisa_irq_edge= [PARISC,HW]
676 See header of drivers/parisc/eisa.c.
679 See comment before function elanfreq_setup() in
680 arch/x86/kernel/cpu/cpufreq/elanfreq.c.
683 Format: {"anticipatory" | "cfq" | "deadline" | "noop"}
684 See Documentation/block/as-iosched.txt and
685 Documentation/block/deadline-iosched.txt for details.
687 elfcorehdr= [X86-32, X86_64]
688 Specifies physical address of start of kernel core
689 image elf header. Generally kexec loader will
690 pass this option to capture kernel.
691 See Documentation/kdump/kdump.txt for details.
693 enforcing [SELINUX] Set initial enforcing status.
695 See security/selinux/Kconfig help text.
696 0 -- permissive (log only, no denials).
697 1 -- enforcing (deny and log).
699 Value can be changed at runtime via /selinux/enforce.
702 Format: <spdif>,[<nomix>,[<amplifier>]]
703 See also header of sound/oss/es1371.c.
705 ether= [HW,NET] Ethernet cards parameters
706 This option is obsoleted by the "netdev=" option, which
707 has equivalent usage. See its documentation for details.
709 eurwdt= [HW,WDT] Eurotech CPU-1220/1410 onboard watchdog.
714 fail_make_request=[KNL]
715 General fault injection mechanism.
716 Format: <interval>,<probability>,<space>,<times>
717 See also /Documentation/fault-injection/.
720 See header of drivers/scsi/fd_mcs.c.
723 See header of drivers/scsi/fdomain.c.
726 See Documentation/floppy.txt.
728 force_pal_cache_flush
729 [IA-64] Avoid check_sal_cache_flush which may hang on
730 buggy SAL_CACHE_FLUSH implementations. Using this
731 parameter will force ia64_sal_cache_flush to call
732 ia64_pal_cache_flush instead of SAL_CACHE_FLUSH.
735 [HW,JOY] Multisystem joystick and NES/SNES/PSX pad
736 support via parallel port (up to 5 devices per port)
737 Format: <port#>,<pad1>,<pad2>,<pad3>,<pad4>,<pad5>
738 See also Documentation/input/joystick-parport.txt
742 gart_fix_e820= [X86_64] disable the fix e820 for K8 GART
747 See header of drivers/scsi/gdth.c.
749 gpt [EFI] Forces disk with valid GPT signature but
750 invalid Protective MBR to be treated as GPT.
754 hashdist= [KNL,NUMA] Large hashes allocated during boot
755 are distributed across NUMA nodes. Defaults on
756 for IA-64, off otherwise.
757 Format: 0 | 1 (for off | on)
759 hcl= [IA-64] SGI's Hardware Graph compatibility layer
761 hd= [EIDE] (E)IDE hard drive subsystem geometry
762 Format: <cyl>,<head>,<sect>
764 highmem=nn[KMG] [KNL,BOOT] forces the highmem zone to have an exact
765 size of <nn>. This works even on boxes that have no
766 highmem otherwise. This also works to reduce highmem
767 size on bigger boxes.
769 highres= [KNL] Enable/disable high resolution timer mode.
770 Valid parameters: "on", "off"
774 See Documentation/isdn/README.HiSax.
776 hugepages= [HW,X86-32,IA-64] HugeTLB pages to allocate at boot.
777 hugepagesz= [HW,IA-64,PPC,X86-64] The size of the HugeTLB pages.
778 On x86-64 and powerpc, this option can be specified
779 multiple times interleaved with hugepages= to reserve
780 huge pages of different sizes. Valid pages sizes on
781 x86-64 are 2M (when the CPU supports "pse") and 1G
782 (when the CPU supports the "pdpe1gb" cpuinfo flag)
783 Note that 1GB pages can only be allocated at boot time
784 using hugepages= and not freed afterwards.
786 [same as hugepagesz=] The size of the default
787 HugeTLB page size. This is the size represented by
788 the legacy /proc/ hugepages APIs, used for SHM, and
789 default size when mounting hugetlbfs filesystems.
790 Defaults to the default architecture's huge page size
793 i8042.direct [HW] Put keyboard port into non-translated mode
794 i8042.dumbkbd [HW] Pretend that controller can only read data from
795 keyboard and cannot control its state
796 (Don't attempt to blink the leds)
797 i8042.noaux [HW] Don't check for auxiliary (== mouse) port
798 i8042.nokbd [HW] Don't check/create keyboard port
799 i8042.noloop [HW] Disable the AUX Loopback command while probing
801 i8042.nomux [HW] Don't check presence of an active multiplexing
803 i8042.nopnp [HW] Don't use ACPIPnP / PnPBIOS to discover KBD/AUX
806 [HW] Frequency with which keyboard LEDs should blink
807 when kernel panics (default is 0.5 sec)
808 i8042.reset [HW] Reset the controller during init and cleanup
809 i8042.unlock [HW] Unlock (ignore) the keylock
813 i8k.ignore_dmi [HW] Continue probing hardware even if DMI data
814 indicates that the driver is running on unsupported
816 i8k.force [HW] Activate i8k driver even if SMM BIOS signature
817 does not match list of supported models.
819 [HW] Report power status in /proc/i8k
820 (disabled by default)
821 i8k.restricted [HW] Allow controlling fans only if SYS_ADMIN
824 ibmmcascsi= [HW,MCA,SCSI] IBM MicroChannel SCSI adapter
825 See Documentation/mca.txt.
828 Format: <io>[,<membase>[,<icn_id>[,<icn_id2>]]]
830 ide= [HW] (E)IDE subsystem
831 Format: ide=nodma or ide=doubler
832 See Documentation/ide/ide.txt.
834 idebus= [HW] (E)IDE subsystem - VLB/PCI bus speed
835 See Documentation/ide/ide.txt.
838 Format: idle=poll or idle=mwait, idle=halt, idle=nomwait
839 Poll forces a polling idle loop that can slightly improves the performance
840 of waking up a idle CPU, but will use a lot of power and make the system
841 run hot. Not recommended.
842 idle=mwait. On systems which support MONITOR/MWAIT but the kernel chose
843 to not use it because it doesn't save as much power as a normal idle
844 loop use the MONITOR/MWAIT idle loop anyways. Performance should be the same
846 idle=halt. Halt is forced to be used for CPU idle.
847 In such case C2/C3 won't be used again.
848 idle=nomwait. Disable mwait for CPU C-states
850 ide-pci-generic.all-generic-ide [HW] (E)IDE subsystem
851 Claim all unknown PCI IDE storage controllers.
853 ignore_loglevel [KNL]
854 Ignore loglevel setting - this will print /all/
855 kernel messages to the console. Useful for debugging.
858 Set number of hash buckets for inode cache.
861 See header of drivers/scsi/in2000.c.
865 Run specified binary instead of /sbin/init as init
868 initcall_debug [KNL] Trace initcalls as they are executed. Useful
869 for working out where the kernel is dying during
872 initrd= [BOOT] Specify the location of the initial ramdisk
874 inport.irq= [HW] Inport (ATI XL and Microsoft) busmouse driver
892 intel_iommu= [DMAR] Intel IOMMU driver (DMAR) option
894 Disable intel iommu driver.
895 igfx_off [Default Off]
896 By default, gfx is mapped as normal device. If a gfx
897 device has a dedicated DMAR unit, the DMAR unit is
898 bypassed by not enabling DMAR with this option. In
899 this case, gfx device will use physical address for
902 With this option iommu will not optimize to look
903 for io virtual address below 32 bit forcing dual
904 address cycle on pci bus for cards supporting greater
905 than 32 bit addressing. The default is to look
906 for translation below 32 bit and if not available
907 then look in the higher range.
909 With this option on every unmap_single operation will
910 result in a hardware IOTLB flush operation as opposed
911 to batching them for performance.
913 io_delay= [X86-32,X86-64] I/O delay method
915 Standard port 0x80 based delay
917 Alternate port 0xed based delay (needed on some systems)
919 Simple two microseconds delay
923 io7= [HW] IO7 for Marvel based alpha systems
924 See comment before marvel_specify_io7 in
925 arch/alpha/kernel/core_marvel.c.
928 See Documentation/filesystems/nfsroot.txt.
930 ip2= [HW] Set IO/IRQ pairs for up to 4 IntelliPort boards
931 See comment before ip2_setup() in
932 drivers/char/ip2/ip2base.c.
934 ips= [HW,SCSI] Adaptec / IBM ServeRAID controller
935 See header of drivers/scsi/ips.c.
937 ports= [IP_VS_FTP] IPVS ftp helper module
939 Up to 8 (IP_VS_APP_MAX_PORTS) ports
941 Format: <port>,<port>....
944 When an interrupt is not handled search all handlers
945 for it. Intended to get systems with badly broken
949 When an interrupt is not handled search all handlers
950 for it. Also check all handlers each timer
951 interrupt. Intended to get systems with badly broken
955 Format: <RDP>,<reset>,<pci_scan>,<verbosity>
957 isolcpus= [KNL,SMP] Isolate CPUs from the general scheduler.
959 <cpu number>,...,<cpu number>
961 <cpu number>-<cpu number> (must be a positive range in ascending order)
963 <cpu number>,...,<cpu number>-<cpu number>
964 This option can be used to specify one or more CPUs
965 to isolate from the general SMP balancing and scheduling
966 algorithms. The only way to move a process onto or off
967 an "isolated" CPU is via the CPU affinity syscalls.
968 <cpu number> begins at 0 and the maximum value is
969 "number of CPUs in system - 1".
971 This option is the preferred way to isolate CPUs. The
972 alternative -- manually setting the CPU mask of all
973 tasks in the system -- can cause problems and
974 suboptimal load balancer performance.
978 js= [HW,JOY] Analog joystick
979 See Documentation/input/joystick.txt.
981 kernelcore=nn[KMG] [KNL,X86-32,IA-64,PPC,X86-64] This parameter
982 specifies the amount of memory usable by the kernel
983 for non-movable allocations. The requested amount is
984 spread evenly throughout all nodes in the system. The
985 remaining memory in each node is used for Movable
986 pages. In the event, a node is too small to have both
987 kernelcore and Movable pages, kernelcore pages will
988 take priority and other nodes will have a larger number
989 of kernelcore pages. The Movable zone is used for the
990 allocation of pages that may be reclaimed or moved
991 by the page migration subsystem. This means that
992 HugeTLB pages may not be allocated from this zone.
993 Note that allocations like PTEs-from-HighMem still
994 use the HighMem zone if it exists, and the Normal
997 movablecore=nn[KMG] [KNL,X86-32,IA-64,PPC,X86-64] This parameter
998 is similar to kernelcore except it specifies the
999 amount of memory used for migratable allocations.
1000 If both kernelcore and movablecore is specified,
1001 then kernelcore will be at *least* the specified
1002 value but may be more. If movablecore on its own
1003 is specified, the administrator must be careful
1004 that the amount of memory usable for all allocations
1009 kstack=N [X86-32,X86-64] Print N words from the kernel stack
1012 kgdboc= [HW] kgdb over consoles.
1013 Requires a tty driver that supports console polling.
1014 (only serial suported for now)
1015 Format: <serial_device>[,baud]
1017 kmac= [MIPS] korina ethernet MAC address.
1018 Configure the RouterBoard 532 series on-chip
1019 Ethernet adapter MAC address.
1025 lapic [X86-32,APIC] Enable the local APIC even if BIOS
1028 lapic_timer_c2_ok [X86-32,x86-64,APIC] trust the local apic timer in
1031 libata.dma= [LIBATA] DMA control
1032 libata.dma=0 Disable all PATA and SATA DMA
1033 libata.dma=1 PATA and SATA Disk DMA only
1034 libata.dma=2 ATAPI (CDROM) DMA only
1035 libata.dma=4 Compact Flash DMA only
1036 Combinations also work, so libata.dma=3 enables DMA
1037 for disks and CDROMs, but not CFs.
1039 libata.noacpi [LIBATA] Disables use of ACPI in libata suspend/resume
1043 libata.force= [LIBATA] Force configurations. The format is comma
1044 separated list of "[ID:]VAL" where ID is
1045 PORT[:DEVICE]. PORT and DEVICE are decimal numbers
1046 matching port, link or device. Basically, it matches
1047 the ATA ID string printed on console by libata. If
1048 the whole ID part is omitted, the last PORT and DEVICE
1049 values are used. If ID hasn't been specified yet, the
1050 configuration applies to all ports, links and devices.
1052 If only DEVICE is omitted, the parameter applies to
1053 the port and all links and devices behind it. DEVICE
1054 number of 0 either selects the first device or the
1055 first fan-out link behind PMP device. It does not
1056 select the host link. DEVICE number of 15 selects the
1057 host link and device attached to it.
1059 The VAL specifies the configuration to force. As long
1060 as there's no ambiguity shortcut notation is allowed.
1061 For example, both 1.5 and 1.5G would work for 1.5Gbps.
1062 The following configurations can be forced.
1064 * Cable type: 40c, 80c, short40c, unk, ign or sata.
1065 Any ID with matching PORT is used.
1067 * SATA link speed limit: 1.5Gbps or 3.0Gbps.
1069 * Transfer mode: pio[0-7], mwdma[0-4] and udma[0-7].
1070 udma[/][16,25,33,44,66,100,133] notation is also
1073 * [no]ncq: Turn on or off NCQ.
1075 * nohrst, nosrst, norst: suppress hard, soft
1078 If there are multiple matching configurations changing
1079 the same attribute, the last one is used.
1081 load_ramdisk= [RAM] List of ramdisks to load from floppy
1082 See Documentation/ramdisk.txt.
1084 lockd.nlm_grace_period=P [NFS] Assign grace period.
1087 lockd.nlm_tcpport=N [NFS] Assign TCP port.
1090 lockd.nlm_timeout=T [NFS] Assign timeout value.
1093 lockd.nlm_udpport=M [NFS] Assign UDP port.
1096 logibm.irq= [HW,MOUSE] Logitech Bus Mouse Driver
1099 loglevel= All Kernel Messages with a loglevel smaller than the
1100 console loglevel will be printed to the console. It can
1101 also be changed with klogd or other programs. The
1102 loglevels are defined as follows:
1104 0 (KERN_EMERG) system is unusable
1105 1 (KERN_ALERT) action must be taken immediately
1106 2 (KERN_CRIT) critical conditions
1107 3 (KERN_ERR) error conditions
1108 4 (KERN_WARNING) warning conditions
1109 5 (KERN_NOTICE) normal but significant condition
1110 6 (KERN_INFO) informational
1111 7 (KERN_DEBUG) debug-level messages
1113 log_buf_len=n Sets the size of the printk ring buffer, in bytes.
1114 Format: { n | nk | nM }
1115 n must be a power of two. The default size
1116 is set in the kernel config file.
1118 logo.nologo [FB] Disables display of the built-in Linux logo.
1119 This may be used to provide more screen space for
1120 kernel log messages and is useful when debugging
1121 kernel boot problems.
1123 lp=0 [LP] Specify parallel ports to use, e.g,
1124 lp=port[,port...] lp=none,parport0 (lp0 not configured, lp1 uses
1125 lp=reset first parallel port). 'lp=0' disables the
1126 lp=auto printer driver. 'lp=reset' (which can be
1127 specified in addition to the ports) causes
1128 attached printers to be reset. Using
1129 lp=port1,port2,... specifies the parallel ports
1130 to associate lp devices with, starting with
1131 lp0. A port specification may be 'none' to skip
1132 that lp device, or a parport name such as
1133 'parport0'. Specifying 'lp=auto' instead of a
1134 port specification list means that device IDs
1135 from each port should be examined, to see if
1136 an IEEE 1284-compliant printer is attached; if
1137 so, the driver will manage that printer.
1138 See also header of drivers/char/lp.c.
1141 Sets loops_per_jiffy to given constant, thus avoiding
1142 time-consuming boot-time autodetection (up to 250 ms per
1143 CPU). 0 enables autodetection (default). To determine
1144 the correct value for your kernel, boot with normal
1145 autodetection and see what value is printed. Note that
1146 on SMP systems the preset will be applied to all CPUs,
1147 which is likely to cause problems if your CPUs need
1148 significantly divergent settings. An incorrect value
1149 will cause delays in the kernel to be wrong, leading to
1150 unpredictable I/O errors and other breakage. Although
1151 unlikely, in the extreme case this might damage your
1155 Format: <io>,<irq>,<dma>
1157 mac5380= [HW,SCSI] Format:
1158 <can_queue>,<cmd_per_lun>,<sg_tablesize>,<hostid>,<use_tags>
1160 machvec= [IA64] Force the use of a particular machine-vector
1161 (machvec) in a generic kernel.
1162 Example: machvec=hpzx1_swiotlb
1164 max_loop= [LOOP] Maximum number of loopback devices that can
1168 maxcpus= [SMP] Maximum number of processors that an SMP kernel
1169 should make use of. maxcpus=n : n >= 0 limits the
1170 kernel to using 'n' processors. n=0 is a special case,
1171 it is equivalent to "nosmp", which also disables
1174 max_addr=[KMG] [KNL,BOOT,ia64] All physical memory greater than or
1175 equal to this physical address is ignored.
1177 max_luns= [SCSI] Maximum number of LUNs to probe.
1178 Should be between 1 and 2^32-1.
1181 [SCSI] Maximum number of LUNs received.
1182 Should be between 1 and 16384.
1186 mce [X86-32] Machine Check Exception
1188 mce=option [X86-64] See Documentation/x86_64/boot-options.txt
1190 md= [HW] RAID subsystems devices and level
1191 See Documentation/md.txt.
1194 Format: <first>,<last>
1195 Specifies range of consoles to be captured by the MDA.
1197 mem=nn[KMG] [KNL,BOOT] Force usage of a specific amount of memory
1198 Amount of memory to be used when the kernel is not able
1199 to see the whole system memory or for test.
1200 [X86-32] Use together with memmap= to avoid physical
1201 address space collisions. Without memmap= PCI devices
1202 could be placed at addresses belonging to unused RAM.
1204 mem=nopentium [BUGS=X86-32] Disable usage of 4MB pages for kernel
1207 memmap=exactmap [KNL,X86-32,X86_64] Enable setting of an exact
1208 E820 memory map, as specified by the user.
1209 Such memmap=exactmap lines can be constructed based on
1210 BIOS output or other requirements. See the memmap=nn@ss
1213 memmap=nn[KMG]@ss[KMG]
1214 [KNL] Force usage of a specific region of memory
1215 Region of memory to be used, from ss to ss+nn.
1217 memmap=nn[KMG]#ss[KMG]
1218 [KNL,ACPI] Mark specific memory as ACPI data.
1219 Region of memory to be used, from ss to ss+nn.
1221 memmap=nn[KMG]$ss[KMG]
1222 [KNL,ACPI] Mark specific memory as reserved.
1223 Region of memory to be used, from ss to ss+nn.
1224 Example: Exclude memory from 0x18690000-0x1869ffff
1225 memmap=64K$0x18690000
1227 memmap=0x10000$0x18690000
1229 memtest= [KNL,X86] Enable memtest
1231 range: 0,4 : pattern number
1232 default : 0 <disable>
1234 meye.*= [HW] Set MotionEye Camera parameters
1235 See Documentation/video4linux/meye.txt.
1237 mfgpt_irq= [IA-32] Specify the IRQ to use for the
1238 Multi-Function General Purpose Timers on AMD Geode
1241 mfgptfix [X86-32] Fix MFGPT timers on AMD Geode platforms when
1242 the BIOS has incorrectly applied a workaround. TinyBIOS
1243 version 0.98 is known to be affected, 0.99 fixes the
1244 problem by letting the user disable the workaround.
1249 [KNL] When CONFIG_DEBUG_MEMORY_INIT is set, this
1250 parameter allows control of the logging verbosity for
1251 the additional memory initialisation checks. A value
1252 of 0 disables mminit logging and a level of 4 will
1253 log everything. Information is printed at KERN_DEBUG
1254 so loglevel=8 may also need to be specified.
1257 [MOUSE] Maximum time between finger touching and
1258 leaving touchpad surface for touch to be considered
1259 a tap and be reported as a left button click (for
1260 touchpads working in absolute mode only).
1262 mousedev.xres= [MOUSE] Horizontal screen resolution, used for devices
1263 reporting absolute coordinates, such as tablets
1264 mousedev.yres= [MOUSE] Vertical screen resolution, used for devices
1265 reporting absolute coordinates, such as tablets
1270 MTD_Partition= [MTD]
1271 Format: <name>,<region-number>,<size>,<offset>
1273 MTD_Region= [MTD] Format:
1274 <name>,<region-number>[,<base>,<size>,<buswidth>,<altbuswidth>]
1277 See drivers/mtd/cmdlinepart.c.
1280 ARM/S3C2412 JIVE boot control
1282 See arch/arm/mach-s3c2412/mach-jive.c
1284 mtouchusb.raw_coordinates=
1285 [HW] Make the MicroTouch USB driver use raw coordinates
1286 ('y', default) or cooked coordinates ('n')
1288 n2= [NET] SDL Inc. RISCom/N2 synchronous serial card
1291 See header of drivers/scsi/NCR_D700.c.
1295 ncr53c400= [HW,SCSI]
1297 ncr53c400a= [HW,SCSI]
1299 ncr53c406a= [HW,SCSI]
1301 ncr53c8xx= [HW,SCSI]
1303 netdev= [NET] Network devices parameters
1304 Format: <irq>,<io>,<mem_start>,<mem_end>,<name>
1305 Note that mem_start is often overloaded to mean
1306 something different and driver-specific.
1307 This usage is only documented in each driver source
1311 [NETFILTER] Enable connection tracking flow accounting
1312 0 to disable accounting
1313 1 to enable accounting
1314 Default value depends on CONFIG_NF_CT_ACCT that is
1315 going to be removed in 2.6.29.
1318 See Documentation/filesystems/nfsroot.txt.
1320 nfsroot= [NFS] nfs root filesystem for disk-less boxes.
1321 See Documentation/filesystems/nfsroot.txt.
1323 nfs.callback_tcpport=
1324 [NFS] set the TCP port on which the NFSv4 callback
1325 channel should listen.
1327 nfs.idmap_cache_timeout=
1328 [NFS] set the maximum lifetime for idmapper cache
1332 [NFS] enable 64-bit inode numbers.
1333 If zero, the NFS client will fake up a 32-bit inode
1334 number for the readdir() and stat() syscalls instead
1335 of returning the full 64-bit number.
1336 The default is to return 64-bit inode numbers.
1338 nmi_debug= [KNL,AVR32] Specify one or more actions to take
1339 when a NMI is triggered.
1340 Format: [state][,regs][,debounce][,die]
1342 nmi_watchdog= [KNL,BUGS=X86-32] Debugging features for SMP kernels
1344 no387 [BUGS=X86-32] Tells the kernel to use the 387 maths
1345 emulation library even if a 387 maths coprocessor
1348 noaliencache [MM, NUMA, SLAB] Disables the allocation of alien
1349 caches in the slab allocator. Saves per-node memory,
1350 but will impact performance.
1354 noapic [SMP,APIC] Tells the kernel to not make use of any
1355 IOAPICs that may be present in the system.
1357 nobats [PPC] Do not use BATs for mapping kernel lowmem
1358 on "Classic" PPC cores.
1362 nodelayacct [KNL] Disable per-task delay accounting
1364 nodisconnect [HW,SCSI,M68K] Disables SCSI disconnects.
1366 noefi [X86-32,X86-64] Disable EFI runtime services support.
1370 noexec [X86-32,X86-64]
1371 On X86-32 available only on PAE configured kernels.
1372 noexec=on: enable non-executable mappings (default)
1373 noexec=off: disable non-executable mappings
1376 This affects only 32-bit executables.
1377 noexec32=on: enable non-executable mappings (default)
1378 read doesn't imply executable mappings
1379 noexec32=off: disable non-executable mappings
1380 read implies executable mappings
1382 nofxsr [BUGS=X86-32] Disables x86 floating point extended
1383 register save and restore. The kernel will only save
1384 legacy floating-point registers on task switch.
1386 noclflush [BUGS=X86] Don't use the CLFLUSH instruction
1390 no-hlt [BUGS=X86-32] Tells the kernel that the hlt
1391 instruction doesn't work correctly and not to
1394 nohalt [IA-64] Tells the kernel not to use the power saving
1395 function PAL_HALT_LIGHT when idle. This increases
1396 power-consumption. On the positive side, it reduces
1397 interrupt wake-up latency, which may improve performance
1398 in certain environments such as networked servers or
1401 nohz= [KNL] Boottime enable/disable dynamic ticks
1402 Valid arguments: on, off
1405 noirqbalance [X86-32,SMP,KNL] Disable kernel irq balancing
1407 noirqdebug [X86-32] Disables the code which attempts to detect and
1408 disable unhandled interrupt sources.
1410 no_timer_check [X86-32,X86_64,APIC] Disables the code which tests for
1411 broken timer IRQ sources.
1413 noisapnp [ISAPNP] Disables ISA PnP code.
1415 noinitrd [RAM] Tells the kernel not to load any configured
1420 nojitter [IA64] Disables jitter checking for ITC timers.
1422 nolapic [X86-32,APIC] Do not enable or use the local APIC.
1424 nolapic_timer [X86-32,APIC] Do not use the local APIC timer.
1426 noltlbs [PPC] Do not use large page/tlb entries for kernel
1427 lowmem mapping on PPC40x.
1429 nomca [IA-64] Disable machine check abort handling
1431 nomce [X86-32] Machine Check Exception
1433 nomfgpt [X86-32] Disable Multi-Function General Purpose
1434 Timer usage (for AMD Geode machines).
1436 noreplace-paravirt [X86-32,PV_OPS] Don't patch paravirt_ops
1438 noreplace-smp [X86-32,SMP] Don't replace SMP instructions
1439 with UP alternatives
1441 noresidual [PPC] Don't use residual data on PReP machines.
1443 noresume [SWSUSP] Disables resume and restores original swap
1446 no-scroll [VGA] Disables scrollback.
1447 This is required for the Braillex ib80-piezo Braille
1448 reader made by F.H. Papenmeier (Germany).
1452 nosep [BUGS=X86-32] Disables x86 SYSENTER/SYSEXIT support.
1454 nosmp [SMP] Tells an SMP kernel to act as a UP kernel,
1455 and disable the IO APIC. legacy for "maxcpus=0".
1457 nosoftlockup [KNL] Disable the soft-lockup detector.
1459 nosync [HW,M68K] Disables sync negotiation for all devices.
1461 notsc [BUGS=X86-32] Disable Time Stamp Counter
1463 nousb [USB] Disable the USB subsystem
1467 nptcg= [IA64] Override max number of concurrent global TLB
1468 purges which is reported from either PAL_VM_SUMMARY or
1471 numa_zonelist_order= [KNL, BOOT] Select zonelist order for NUMA.
1472 one of ['zone', 'node', 'default'] can be specified
1473 This can be set from sysctl after boot.
1474 See Documentation/sysctl/vm.txt for details.
1476 nr_uarts= [SERIAL] maximum number of UARTs to be registered.
1478 olpc_ec_timeout= [OLPC] ms delay when issuing EC commands
1479 Rather than timing out after 20 ms if an EC
1480 command is not properly ACKed, override the length
1481 of the timeout. We have interrupts disabled while
1482 waiting for the ACK, so if this is set too high
1483 interrupts *may* be lost!
1488 oprofile.timer= [HW]
1489 Use timer interrupt instead of performance counters
1491 osst= [HW,SCSI] SCSI Tape Driver
1492 Format: <buffer_size>,<write_threshold>
1493 See also Documentation/scsi/st.txt.
1495 panic= [KNL] Kernel behaviour on panic
1498 parkbd.port= [HW] Parallel port number the keyboard adapter is
1499 connected to, default is 0.
1501 parkbd.mode= [HW] Parallel port keyboard adapter mode of operation,
1502 0 for XT, 1 for AT (default is AT).
1505 parport= [HW,PPT] Specify parallel ports. 0 disables.
1506 Format: { 0 | auto | 0xBBB[,IRQ[,DMA]] }
1507 Use 'auto' to force the driver to use any
1508 IRQ/DMA settings detected (the default is to
1509 ignore detected IRQ/DMA settings because of
1510 possible conflicts). You can specify the base
1511 address, IRQ, and DMA settings; IRQ and DMA
1512 should be numbers, or 'auto' (for using detected
1513 settings on that particular port), or 'nofifo'
1514 (to avoid using a FIFO even if it is detected).
1515 Parallel ports are assigned in the order they
1516 are specified on the command line, starting
1519 parport_init_mode= [HW,PPT]
1520 Configure VIA parallel port to operate in
1521 a specific mode. This is necessary on Pegasos
1522 computer where firmware has no options for setting
1523 up parallel port mode and sets it to spp.
1524 Currently this function knows 686a and 8231 chips.
1525 Format: [spp|ps2|epp|ecp|ecpepp]
1527 pas2= [HW,OSS] Format:
1528 <io>,<irq>,<dma>,<dma16>,<sb_io>,<sb_irq>,<sb_dma>,<sb_dma16>
1531 See header of drivers/scsi/pas16.c.
1534 Halt all CPUs after the first oops has been printed for
1535 the specified number of seconds. This is to be used if
1536 your oopses keep scrolling off the screen.
1541 See header of drivers/block/paride/pcd.c.
1542 See also Documentation/paride.txt.
1544 pci=option[,option...] [PCI] various PCI subsystem options:
1545 off [X86-32] don't probe for the PCI bus
1546 bios [X86-32] force use of PCI BIOS, don't access
1547 the hardware directly. Use this if your machine
1548 has a non-standard PCI host bridge.
1549 nobios [X86-32] disallow use of PCI BIOS, only direct
1550 hardware access methods are allowed. Use this
1551 if you experience crashes upon bootup and you
1552 suspect they are caused by the BIOS.
1553 conf1 [X86-32] Force use of PCI Configuration
1555 conf2 [X86-32] Force use of PCI Configuration
1557 noaer [PCIE] If the PCIEAER kernel config parameter is
1558 enabled, this kernel boot option can be used to
1559 disable the use of PCIE advanced error reporting.
1560 nodomains [PCI] Disable support for multiple PCI
1561 root domains (aka PCI segments, in ACPI-speak).
1562 nommconf [X86-32,X86_64] Disable use of MMCONFIG for PCI
1564 nomsi [MSI] If the PCI_MSI kernel config parameter is
1565 enabled, this kernel boot option can be used to
1566 disable the use of MSI interrupts system-wide.
1567 biosirq [X86-32] Use PCI BIOS calls to get the interrupt
1568 routing table. These calls are known to be buggy
1569 on several machines and they hang the machine
1570 when used, but on other computers it's the only
1571 way to get the interrupt routing table. Try
1572 this option if the kernel is unable to allocate
1573 IRQs or discover secondary PCI buses on your
1575 rom [X86-32] Assign address space to expansion ROMs.
1576 Use with caution as certain devices share
1577 address decoders between ROMs and other
1579 norom [X86-32,X86_64] Do not assign address space to
1580 expansion ROMs that do not already have
1581 BIOS assigned address ranges.
1582 irqmask=0xMMMM [X86-32] Set a bit mask of IRQs allowed to be
1583 assigned automatically to PCI devices. You can
1584 make the kernel exclude IRQs of your ISA cards
1586 pirqaddr=0xAAAAA [X86-32] Specify the physical address
1587 of the PIRQ table (normally generated
1588 by the BIOS) if it is outside the
1589 F0000h-100000h range.
1590 lastbus=N [X86-32] Scan all buses thru bus #N. Can be
1591 useful if the kernel is unable to find your
1592 secondary buses and you want to tell it
1593 explicitly which ones they are.
1594 assign-busses [X86-32] Always assign all PCI bus
1595 numbers ourselves, overriding
1596 whatever the firmware may have done.
1597 usepirqmask [X86-32] Honor the possible IRQ mask stored
1598 in the BIOS $PIR table. This is needed on
1599 some systems with broken BIOSes, notably
1600 some HP Pavilion N5400 and Omnibook XE3
1601 notebooks. This will have no effect if ACPI
1602 IRQ routing is enabled.
1603 noacpi [X86-32] Do not use ACPI for IRQ routing
1604 or for PCI scanning.
1605 use_crs [X86-32] Use _CRS for PCI resource
1607 routeirq Do IRQ routing for all PCI devices.
1608 This is normally done in pci_enable_device(),
1609 so this option is a temporary workaround
1610 for broken drivers that don't call it.
1611 skip_isa_align [X86] do not align io start addr, so can
1612 handle more pci cards
1613 firmware [ARM] Do not re-enumerate the bus but instead
1614 just use the configuration from the
1615 bootloader. This is currently used on
1616 IXP2000 systems where the bus has to be
1617 configured a certain way for adjunct CPUs.
1618 noearly [X86] Don't do any early type 1 scanning.
1619 This might help on some broken boards which
1620 machine check when some devices' config space
1621 is read. But various workarounds are disabled
1622 and some IOMMU drivers will not work.
1623 bfsort Sort PCI devices into breadth-first order.
1624 This sorting is done to get a device
1625 order compatible with older (<= 2.4) kernels.
1626 nobfsort Don't sort PCI devices into breadth-first order.
1627 cbiosize=nn[KMG] The fixed amount of bus space which is
1628 reserved for the CardBus bridge's IO window.
1629 The default value is 256 bytes.
1630 cbmemsize=nn[KMG] The fixed amount of bus space which is
1631 reserved for the CardBus bridge's memory
1632 window. The default value is 64 megabytes.
1634 pcmv= [HW,PCMCIA] BadgePAD 4
1637 See Documentation/paride.txt.
1639 pdcchassis= [PARISC,HW] Disable/Enable PDC Chassis Status codes at
1642 See arch/parisc/kernel/pdc_chassis.c
1645 See Documentation/paride.txt.
1648 See Documentation/paride.txt.
1650 pirq= [SMP,APIC] Manual mp-table setup
1651 See Documentation/i386/IO-APIC.txt.
1653 plip= [PPT,NET] Parallel port network link
1654 Format: { parport<nr> | timid | 0 }
1655 See also Documentation/parport.txt.
1657 pmtmr= [X86] Manual setup of pmtmr I/O Port.
1658 Override pmtimer IOPort with a hex value.
1665 { on | off | curr | res | no-curr | no-res }
1668 [ISAPNP] Exclude IRQs for the autoconfiguration
1671 [ISAPNP] Exclude DMAs for the autoconfiguration
1673 pnp_reserve_io= [ISAPNP] Exclude I/O ports for the autoconfiguration
1674 Ranges are in pairs (I/O port base and size).
1677 [ISAPNP] Exclude memory regions for the
1679 Ranges are in pairs (memory base and size).
1681 print-fatal-signals=
1682 [KNL] debug: print fatal signals
1683 print-fatal-signals=1: print segfault info to
1687 printk.time= Show timing data prefixed to each printk message line
1688 Format: <bool> (1/Y/y=enable, 0/N/n=disable)
1690 profile= [KNL] Enable kernel profiling via /proc/profile
1691 Format: [schedule,]<number>
1692 Param: "schedule" - profile schedule points.
1693 Param: <number> - step/bucket size as a power of 2 for
1694 statistical time based profiling.
1695 Param: "sleep" - profile D-state sleeping (millisecs).
1696 Requires CONFIG_SCHEDSTATS
1697 Param: "kvm" - profile VM exits.
1699 processor.max_cstate= [HW,ACPI]
1700 Limit processor to maximum C-state
1701 max_cstate=9 overrides any DMI blacklist limit.
1703 processor.nocst [HW,ACPI]
1704 Ignore the _CST method to determine C-states,
1705 instead using the legacy FADT method
1707 prompt_ramdisk= [RAM] List of RAM disks to prompt for floppy disk
1709 See Documentation/ramdisk.txt.
1711 psmouse.proto= [HW,MOUSE] Highest PS2 mouse protocol extension to
1712 probe for; one of (bare|imps|exps|lifebook|any).
1713 psmouse.rate= [HW,MOUSE] Set desired mouse report rate, in reports
1715 psmouse.resetafter= [HW,MOUSE]
1716 Try to reset the device after so many bad packets
1719 [HW,MOUSE] Set desired mouse resolution, in dpi.
1720 psmouse.smartscroll=
1721 [HW,MOUSE] Controls Logitech smartscroll autorepeat.
1722 0 = disabled, 1 = enabled (default).
1724 pss= [HW,OSS] Personal Sound System (ECHO ESC614)
1726 <io>,<mss_io>,<mss_irq>,<mss_dma>,<mpu_io>,<mpu_irq>
1729 See Documentation/paride.txt.
1732 [KNL] Number of legacy pty's. Overwrites compiled-in
1735 quiet [KNL] Disable most log messages
1740 See Documentation/md.txt.
1742 ramdisk_blocksize= [RAM]
1743 See Documentation/ramdisk.txt.
1745 ramdisk_size= [RAM] Sizes of RAM disks in kilobytes
1746 See Documentation/ramdisk.txt.
1748 rcupdate.blimit= [KNL,BOOT]
1749 Set maximum number of finished RCU callbacks to process
1752 rcupdate.qhimark= [KNL,BOOT]
1753 Set threshold of queued
1754 RCU callbacks over which batch limiting is disabled.
1756 rcupdate.qlowmark= [KNL,BOOT]
1757 Set threshold of queued RCU callbacks below which
1758 batch limiting is re-enabled.
1762 Run specified binary instead of /init from the ramdisk,
1763 used for early userspace startup. See initrd.
1765 reboot= [BUGS=X86-32,BUGS=ARM,BUGS=IA-64] Rebooting mode
1766 Format: <reboot_mode>[,<reboot_mode2>[,...]]
1767 See arch/*/kernel/reboot.c or arch/*/kernel/process.c
1770 [KNL, SMP] Set scheduler's default relax_domain_level.
1771 See Documentation/cpusets.txt.
1773 reserve= [KNL,BUGS] Force the kernel to ignore some iomem area
1775 reservetop= [X86-32]
1777 Reserves a hole at the top of the kernel virtual
1780 reset_devices [KNL] Force drivers to reset the underlying device
1781 during initialization.
1784 Specify the partition device for software suspend
1786 resume_offset= [SWSUSP]
1787 Specify the offset from the beginning of the partition
1788 given by "resume=" at which the swap header is located,
1789 in <PAGE_SIZE> units (needed only for swap files).
1790 See Documentation/power/swsusp-and-swap-files.txt
1792 retain_initrd [RAM] Keep initrd memory after extraction
1794 rhash_entries= [KNL,NET]
1795 Set number of hash buckets for route cache
1797 riscom8= [HW,SERIAL]
1798 Format: <io_board1>[,<io_board2>[,...<io_boardN>]]
1800 ro [KNL] Mount root device read-only on boot
1802 root= [KNL] Root filesystem
1804 rootdelay= [KNL] Delay (in seconds) to pause before attempting to
1805 mount the root filesystem
1807 rootflags= [KNL] Set root filesystem mount option string
1809 rootfstype= [KNL] Set root filesystem type
1811 rootwait [KNL] Wait (indefinitely) for root device to show up.
1812 Useful for devices that are detected asynchronously
1813 (e.g. USB and MMC devices).
1815 root_plug.vendor_id=
1816 [ROOTPLUG] Override the default vendor ID
1818 root_plug.product_id=
1819 [ROOTPLUG] Override the default product ID
1822 [ROOTPLUG] Enable debugging output
1824 rw [KNL] Mount root device read-write on boot
1826 S [KNL] Run init in single mode
1829 See drivers/net/irda/sa1100_ir.c.
1831 sbni= [NET] Granch SBNI12 leased line adapter
1833 sc1200wdt= [HW,WDT] SC1200 WDT (watchdog) driver
1834 Format: <io>[,<timeout>[,<isapnp>]]
1836 scsi_debug_*= [SCSI]
1837 See drivers/scsi/scsi_debug.c.
1839 scsi_default_dev_flags=
1840 [SCSI] SCSI default device flags
1843 scsi_dev_flags= [SCSI] Black/white list entry for vendor and model
1844 Format: <vendor>:<model>:<flags>
1845 (flags are integer value)
1847 scsi_logging_level= [SCSI] a bit mask of logging levels
1848 See drivers/scsi/scsi_logging.h for bits. Also
1849 settable via sysctl at dev.scsi.logging_level
1850 (/proc/sys/dev/scsi/logging_level).
1851 There is also a nice 'scsi_logging_level' script in the
1852 S390-tools package, available for download at
1853 http://www-128.ibm.com/developerworks/linux/linux390/s390-tools-1.5.4.html
1855 scsi_mod.scan= [SCSI] sync (default) scans SCSI busses as they are
1856 discovered. async scans them in kernel threads,
1857 allowing boot to proceed. none ignores them, expecting
1858 user space to do the scan.
1860 selinux [SELINUX] Disable or enable SELinux at boot time.
1861 Format: { "0" | "1" }
1862 See security/selinux/Kconfig help text.
1865 Default value is set via kernel config option.
1866 If enabled at boot time, /selinux/disable can be used
1867 later to disable prior to initial policy load.
1869 selinux_compat_net =
1870 [SELINUX] Set initial selinux_compat_net flag value.
1871 Format: { "0" | "1" }
1872 0 -- use new secmark-based packet controls
1873 1 -- use legacy packet controls
1874 Default value is 0 (preferred).
1875 Value can be changed at runtime via
1876 /selinux/compat_net.
1878 serialnumber [BUGS=X86-32]
1881 Maximal number of shapers.
1883 show_msr= [x86] show boot-time MSR settings
1884 Format: { <integer> }
1885 Show boot-time (BIOS-initialized) MSR settings.
1886 The parameter means the number of CPUs to show,
1887 for example 1 means boot CPU only.
1890 See header of drivers/scsi/sim710.c.
1897 slub_debug[=options[,slabs]] [MM, SLUB]
1898 Enabling slub_debug allows one to determine the
1899 culprit if slab objects become corrupted. Enabling
1900 slub_debug can create guard zones around objects and
1901 may poison objects when not in use. Also tracks the
1902 last alloc / free. For more information see
1903 Documentation/vm/slub.txt.
1905 slub_max_order= [MM, SLUB]
1906 Determines the maximum allowed order for slabs.
1907 A high setting may cause OOMs due to memory
1908 fragmentation. For more information see
1909 Documentation/vm/slub.txt.
1911 slub_min_objects= [MM, SLUB]
1912 The minimum number of objects per slab. SLUB will
1913 increase the slab order up to slub_max_order to
1914 generate a sufficiently large slab able to contain
1915 the number of objects indicated. The higher the number
1916 of objects the smaller the overhead of tracking slabs
1917 and the less frequently locks need to be acquired.
1918 For more information see Documentation/vm/slub.txt.
1920 slub_min_order= [MM, SLUB]
1921 Determines the mininum page order for slabs. Must be
1922 lower than slub_max_order.
1923 For more information see Documentation/vm/slub.txt.
1925 slub_nomerge [MM, SLUB]
1926 Disable merging of slabs with similar size. May be
1927 necessary if there is some reason to distinguish
1928 allocs to different slabs. Debug options disable
1929 merging on their own.
1930 For more information see Documentation/vm/slub.txt.
1933 Format: <io1>[,<io2>[,...,<io8>]]
1935 smp-alt-once [X86-32,SMP] On a hotplug CPU system, only
1936 attempt to substitute SMP alternatives once at boot.
1938 smsc-ircc2.nopnp [HW] Don't use PNP to discover SMC devices
1939 smsc-ircc2.ircc_cfg= [HW] Device configuration I/O port
1940 smsc-ircc2.ircc_sir= [HW] SIR base I/O port
1941 smsc-ircc2.ircc_fir= [HW] FIR base I/O port
1942 smsc-ircc2.ircc_irq= [HW] IRQ line
1943 smsc-ircc2.ircc_dma= [HW] DMA channel
1944 smsc-ircc2.ircc_transceiver= [HW] Transceiver type:
1945 0: Toshiba Satellite 1800 (GP data pin select)
1946 1: Fast pin select (default)
1949 snd-ad1816a= [HW,ALSA]
1951 snd-ad1848= [HW,ALSA]
1953 snd-ali5451= [HW,ALSA]
1955 snd-als100= [HW,ALSA]
1957 snd-als4000= [HW,ALSA]
1959 snd-azt2320= [HW,ALSA]
1961 snd-cmi8330= [HW,ALSA]
1963 snd-cmipci= [HW,ALSA]
1965 snd-cs4231= [HW,ALSA]
1967 snd-cs4232= [HW,ALSA]
1969 snd-cs4236= [HW,ALSA]
1971 snd-cs4281= [HW,ALSA]
1973 snd-cs46xx= [HW,ALSA]
1975 snd-dt019x= [HW,ALSA]
1977 snd-dummy= [HW,ALSA]
1979 snd-emu10k1= [HW,ALSA]
1981 snd-ens1370= [HW,ALSA]
1983 snd-ens1371= [HW,ALSA]
1985 snd-es968= [HW,ALSA]
1987 snd-es1688= [HW,ALSA]
1989 snd-es18xx= [HW,ALSA]
1991 snd-es1938= [HW,ALSA]
1993 snd-es1968= [HW,ALSA]
1995 snd-fm801= [HW,ALSA]
1997 snd-gusclassic= [HW,ALSA]
1999 snd-gusextreme= [HW,ALSA]
2001 snd-gusmax= [HW,ALSA]
2005 snd-ice1712= [HW,ALSA]
2007 snd-intel8x0= [HW,ALSA]
2009 snd-interwave= [HW,ALSA]
2014 snd-korg1212= [HW,ALSA]
2016 snd-maestro3= [HW,ALSA]
2018 snd-mpu401= [HW,ALSA]
2020 snd-mtpav= [HW,ALSA]
2022 snd-nm256= [HW,ALSA]
2024 snd-opl3sa2= [HW,ALSA]
2032 snd-opti93x= [HW,ALSA]
2036 snd-rme32= [HW,ALSA]
2038 snd-rme96= [HW,ALSA]
2040 snd-rme9652= [HW,ALSA]
2046 snd-sbawe= [HW,ALSA]
2048 snd-serial= [HW,ALSA]
2050 snd-sgalaxy= [HW,ALSA]
2052 snd-sonicvibes= [HW,ALSA]
2057 snd-sun-cs4231= [HW,ALSA]
2059 snd-trident= [HW,ALSA]
2061 snd-usb-audio= [HW,ALSA,USB]
2063 snd-via82xx= [HW,ALSA]
2065 snd-virmidi= [HW,ALSA]
2067 snd-wavefront= [HW,ALSA]
2069 snd-ymfpci= [HW,ALSA]
2072 [KNL] Should the soft-lockup detector generate panics.
2074 sonypi.*= [HW] Sony Programmable I/O Control Device driver
2075 See Documentation/sonypi.txt
2077 specialix= [HW,SERIAL] Specialix multi-serial port adapter
2078 See Documentation/specialix.txt.
2080 spia_io_base= [HW,MTD]
2086 Format: <io>,<irq>,<dma>,<mpu_io>,<mpu_irq>
2088 st= [HW,SCSI] SCSI tape parameters (buffers, etc.)
2089 See Documentation/scsi/st.txt.
2093 Set the STI (builtin display/keyboard on the HP-PARISC
2094 machines) console (graphic card) which should be used
2095 as the initial boot-console.
2096 See also comment in drivers/video/console/sticore.c.
2099 See comment in drivers/video/console/sticore.c.
2102 Format: bpp:<bpp1>[:<bpp2>[:<bpp3>...]]
2106 Control how the NFS server code allocates CPUs to
2107 service thread pools. Depending on how many NICs
2108 you have and where their interrupts are bound, this
2109 option will affect which CPUs will do NFS serving.
2110 Note: this parameter cannot be changed while the
2111 NFS server is running.
2113 auto the server chooses an appropriate mode
2114 automatically using heuristics
2115 global a single global pool contains all CPUs
2116 percpu one pool for each CPU
2117 pernode one pool for each NUMA node (equivalent
2118 to global on non-NUMA machines)
2120 swiotlb= [IA-64] Number of I/O TLB slabs
2124 sym53c416= [HW,SCSI]
2125 See header of drivers/scsi/sym53c416.c.
2127 sysrq_always_enabled
2129 Ignore sysrq setting - this boot parameter will
2130 neutralize any effect of /proc/sys/kernel/sysrq.
2131 Useful for debugging.
2134 See header of drivers/scsi/t128.c.
2138 test_suspend= [SUSPEND]
2139 Specify "mem" (for Suspend-to-RAM) or "standby" (for
2140 standby suspend) as the system sleep state to briefly
2141 enter during system startup. The system is woken from
2142 this state using a wakeup-capable RTC alarm.
2144 thash_entries= [KNL,NET]
2145 Set number of hash buckets for TCP connection
2147 thermal.act= [HW,ACPI]
2148 -1: disable all active trip points in all thermal zones
2149 <degrees C>: override all lowest active trip points
2151 thermal.crt= [HW,ACPI]
2152 -1: disable all critical trip points in all thermal zones
2153 <degrees C>: lower all critical trip points
2155 thermal.nocrt= [HW,ACPI]
2156 Set to disable actions on ACPI thermal zone
2157 critical and hot trip points.
2159 thermal.off= [HW,ACPI]
2160 1: disable ACPI thermal control
2162 thermal.psv= [HW,ACPI]
2163 -1: disable all passive trip points
2164 <degrees C>: override all passive trip points to this value
2166 thermal.tzp= [HW,ACPI]
2167 Specify global default ACPI thermal zone polling rate
2168 <deci-seconds>: poll all this frequency
2169 0: no polling (default)
2172 See comment before function dc390_setup() in
2173 drivers/scsi/tmscsim.c.
2177 trix= [HW,OSS] MediaTrix AudioTrix Pro
2179 <io>,<irq>,<dma>,<dma2>,<sb_io>,<sb_irq>,<sb_dma>,<mpu_io>,<mpu_irq>
2181 turbografx.map[2|3]= [HW,JOY]
2182 TurboGraFX parallel port interface
2184 <port#>,<js1>,<js2>,<js3>,<js4>,<js5>,<js6>,<js7>
2185 See also Documentation/input/joystick-parport.txt
2187 u14-34f= [HW,SCSI] UltraStor 14F/34F SCSI host adapter
2188 See header of drivers/scsi/u14-34f.c.
2197 [USB] Ignore overcurrent events (default N).
2198 Some badly-designed motherboards generate lots of
2199 bogus events, for ports that aren't wired to
2200 anything. Set this parameter to avoid log spamming.
2201 Note that genuine overcurrent events won't be
2206 Set unknown_nmi_panic=1 early on boot.
2208 usbcore.autosuspend=
2209 [USB] The autosuspend time delay (in seconds) used
2210 for newly-detected USB devices (default 2). This
2211 is the time required before an idle device will be
2212 autosuspended. Devices for which the delay is set
2213 to a negative value won't be autosuspended at all.
2216 [USBHID] The interval which mice are to be polled at.
2218 add_efi_memmap [EFI; x86-32,X86-64] Include EFI memory map in
2219 kernel's map of available physical RAM.
2221 vdso= [X86-32,SH,x86-64]
2222 vdso=2: enable compat VDSO (default with COMPAT_VDSO)
2223 vdso=1: enable VDSO (default)
2224 vdso=0: disable VDSO mapping
2226 vdso32= [X86-32,X86-64]
2227 vdso32=2: enable compat VDSO (default with COMPAT_VDSO)
2228 vdso32=1: enable 32-bit VDSO (default)
2229 vdso32=0: disable 32-bit VDSO mapping
2232 vector=percpu: enable percpu vector domain
2234 video= [FB] Frame buffer configuration
2235 See Documentation/fb/modedb.txt.
2237 vga= [BOOT,X86-32] Select a particular video mode
2238 See Documentation/i386/boot.txt and
2239 Documentation/svga.txt.
2240 Use vga=ask for menu.
2241 This is actually a boot loader parameter; the value is
2242 passed to the kernel using a special protocol.
2244 vmalloc=nn[KMG] [KNL,BOOT] Forces the vmalloc area to have an exact
2245 size of <nn>. This can be used to increase the
2246 minimum size (128MB on x86). It can also be used to
2247 decrease the size and leave more room for directly
2250 vmhalt= [KNL,S390] Perform z/VM CP command after system halt.
2253 vmpanic= [KNL,S390] Perform z/VM CP command after kernel panic.
2256 vmpoff= [KNL,S390] Perform z/VM CP command after power off.
2259 waveartist= [HW,OSS]
2260 Format: <io>,<irq>,<dma>,<dma2>
2263 See header of drivers/scsi/wd33c93.c.
2266 See header of drivers/scsi/wd7000.c.
2269 See Documentation/watchdog/wdt.txt.
2271 xd= [HW,XT] Original XT pre-IDE (RLL encoded) disks.
2272 xd_geo= See header of drivers/block/xd.c.
2274 xirc2ps_cs= [NET,PCMCIA]
2276 <irq>,<irq_mask>,<io>,<full_duplex>,<do_sound>,<lockup_hack>[,<irq2>[,<irq3>[,<irq4>]]]
2278 norandmaps Don't use address space randomization
2279 Equivalent to echo 0 > /proc/sys/kernel/randomize_va_space
2281 ______________________________________________________________________
2285 Add documentation for ALSA options.
2286 Add more DRM drivers.