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/x86_64/boot-options.txt .
104 X86 Either 32bit or 64bit x86 (same as X86-32+X86-64)
106 In addition, the following text indicates that the option:
108 BUGS= Relates to possible processor bugs on the said processor.
109 KNL Is a kernel start-up parameter.
110 BOOT Is a boot loader parameter.
112 Parameters denoted with BOOT are actually interpreted by the boot
113 loader, and have no meaning to the kernel directly.
114 Do not modify the syntax of boot loader parameters without extreme
115 need or coordination with <Documentation/x86/i386/boot.txt>.
117 There are also arch-specific kernel-parameters not documented here.
118 See for example <Documentation/x86/x86_64/boot-options.txt>.
120 Note that ALL kernel parameters listed below are CASE SENSITIVE, and that
121 a trailing = on the name of any parameter states that that parameter will
122 be entered as an environment variable, whereas its absence indicates that
123 it will appear as a kernel argument readable via /proc/cmdline by programs
124 running once the system is up.
126 The number of kernel parameters is not limited, but the length of the
127 complete command line (parameters including spaces etc.) is limited to
128 a fixed number of characters. This limit depends on the architecture
129 and is between 256 and 4096 characters. It is defined in the file
130 ./include/asm/setup.h as COMMAND_LINE_SIZE.
133 acpi= [HW,ACPI,X86-64,i386]
134 Advanced Configuration and Power Interface
135 Format: { force | off | ht | strict | noirq }
136 force -- enable ACPI if default was off
137 off -- disable ACPI if default was on
138 noirq -- do not use ACPI for IRQ routing
139 ht -- run only enough ACPI to enable Hyper Threading
140 strict -- Be less tolerant of platforms that are not
141 strictly ACPI specification compliant.
143 See also Documentation/power/pm.txt, pci=noacpi
145 acpi_apic_instance= [ACPI, IOAPIC]
147 2: use 2nd APIC table, if available
148 1,0: use 1st APIC table
151 acpi_sleep= [HW,ACPI] Sleep options
152 Format: { s3_bios, s3_mode, s3_beep, s4_nohwsig, old_ordering }
153 See Documentation/power/video.txt for s3_bios and s3_mode.
154 s3_beep is for debugging; it makes the PC's speaker beep
155 as soon as the kernel's real-mode entry point is called.
156 s4_nohwsig prevents ACPI hardware signature from being
157 used during resume from hibernation.
158 old_ordering causes the ACPI 1.0 ordering of the _PTS
159 control method, wrt putting devices into low power
160 states, to be enforced (the ACPI 2.0 ordering of _PTS is
163 acpi_sci= [HW,ACPI] ACPI System Control Interrupt trigger mode
164 Format: { level | edge | high | low }
166 acpi_irq_balance [HW,ACPI]
167 ACPI will balance active IRQs
170 acpi_irq_nobalance [HW,ACPI]
171 ACPI will not move active IRQs (default)
174 acpi_irq_pci= [HW,ACPI] If irq_balance, clear listed IRQs for
176 Format: <irq>,<irq>...
178 acpi_irq_isa= [HW,ACPI] If irq_balance, mark listed IRQs used by ISA
179 Format: <irq>,<irq>...
181 acpi_no_auto_ssdt [HW,ACPI] Disable automatic loading of SSDT
183 acpi_os_name= [HW,ACPI] Tell ACPI BIOS the name of the OS
184 Format: To spoof as Windows 98: ="Microsoft Windows"
186 acpi_osi= [HW,ACPI] Modify list of supported OS interface strings
187 acpi_osi="string1" # add string1 -- only one string
188 acpi_osi="!string2" # remove built-in string2
189 acpi_osi= # disable all strings
191 acpi_serialize [HW,ACPI] force serialization of AML methods
193 acpi_skip_timer_override [HW,ACPI]
194 Recognize and ignore IRQ0/pin2 Interrupt Override.
195 For broken nForce2 BIOS resulting in XT-PIC timer.
196 acpi_use_timer_override [HW,ACPI}
197 Use timer override. For some broken Nvidia NF5 boards
198 that require a timer override, but don't have
201 acpi_backlight= [HW,ACPI]
202 acpi_backlight=vendor
204 If set to vendor, prefer vendor specific driver
205 (e.g. thinkpad_acpi, sony_acpi, etc.) instead
206 of the ACPI video.ko driver.
208 acpi_display_output= [HW,ACPI]
209 acpi_display_output=vendor
210 acpi_display_output=video
213 acpi.debug_layer= [HW,ACPI]
215 Each bit of the <int> indicates an ACPI debug layer,
216 1: enable, 0: disable. It is useful for boot time
217 debugging. After system has booted up, it can be set
218 via /sys/module/acpi/parameters/debug_layer.
219 CONFIG_ACPI_DEBUG must be enabled for this to produce any output.
220 Available bits (add the numbers together) to enable debug output
221 for specific parts of the ACPI subsystem:
222 0x01 utilities 0x02 hardware 0x04 events 0x08 tables
223 0x10 namespace 0x20 parser 0x40 dispatcher
224 0x80 executer 0x100 resources 0x200 acpica debugger
225 0x400 os services 0x800 acpica disassembler.
226 The number can be in decimal or prefixed with 0x in hex.
227 Warning: Many of these options can produce a lot of
228 output and make your system unusable. Be very careful.
230 acpi.debug_level= [HW,ACPI]
232 Each bit of the <int> indicates an ACPI debug level,
233 which corresponds to the level in an ACPI_DEBUG_PRINT
234 statement. After system has booted up, this mask
235 can be set via /sys/module/acpi/parameters/debug_level.
237 CONFIG_ACPI_DEBUG must be enabled for this to produce
238 any output. The number can be in decimal or prefixed
239 with 0x in hex. Some of these options produce so much
240 output that the system is unusable.
242 The following global components are defined by the
255 0x800 operation region
261 0x20000 user requests
263 The number can be in decimal or prefixed with 0x in hex.
264 Warning: Many of these options can produce a lot of
265 output and make your system unusable. Be very careful.
267 acpi.power_nocheck= [HW,ACPI]
268 Format: 1/0 enable/disable the check of power state.
269 On some bogus BIOS the _PSC object/_STA object of
270 power resource can't return the correct device power
271 state. In such case it is unneccessary to check its
272 power state again in power transition.
273 1 : disable the power state check
275 acpi_pm_good [X86-32,X86-64]
276 Override the pmtimer bug detection: force the kernel
277 to assume that this machine's pmtimer latches its value
278 and always returns good values.
281 { off | try_unsupported }
282 off: disable AGP support
283 try_unsupported: try to drive unsupported chipsets
284 (may crash computer or cause data corruption)
286 enable_timer_pin_1 [i386,x86-64]
287 Enable PIN 1 of APIC timer
288 Can be useful to work around chipset bugs
289 (in particular on some ATI chipsets).
290 The kernel tries to set a reasonable default.
292 disable_timer_pin_1 [i386,x86-64]
293 Disable PIN 1 of APIC timer
294 Can be useful to work around chipset bugs.
297 Format: <io>,<irq>,<dma>,<dma2>,<type>
300 See header of drivers/scsi/advansys.c.
302 advwdt= [HW,WDT] Advantech WDT
303 Format: <iostart>,<iostop>
305 aedsp16= [HW,OSS] Audio Excel DSP 16
306 Format: <io>,<irq>,<dma>,<mss_io>,<mpu_io>,<mpu_irq>
307 See also header of sound/oss/aedsp16.c.
310 See Documentation/scsi/aha152x.txt.
313 Format: <portbase>[,<buson>,<busoff>[,<dmaspeed>]]
316 See Documentation/scsi/aic7xxx.txt.
319 See Documentation/scsi/aic79xx.txt.
321 amd_iommu= [HW,X86-84]
322 Pass parameters to the AMD IOMMU driver in the system.
324 isolate - enable device isolation (each device, as far
325 as possible, will get its own protection
327 fullflush - enable flushing of IO/TLB entries when
328 they are unmapped. Otherwise they are
329 flushed before they will be reused, which
332 amd_iommu_size= [HW,X86-64]
333 Define the size of the aperture for the AMD IOMMU
334 driver. Possible values are:
335 '32M', '64M' (default), '128M', '256M', '512M', '1G'
337 amijoy.map= [HW,JOY] Amiga joystick support
338 Map of devices attached to JOY0DAT and JOY1DAT
340 See also Documentation/kernel/input/joystick.txt
342 analog.map= [HW,JOY] Analog joystick and gamepad support
343 Specifies type or capabilities of an analog joystick
344 connected to one of 16 gameports
345 Format: <type1>,<type2>,..<type16>
348 Power management functions (SPARCstation-4/5 + deriv.)
350 Disable APC CPU standby support. SPARCstation-Fox does
351 not play well with APC CPU idle - disable it if you have
352 APC and your system crashes randomly.
354 apic= [APIC,i386] Advanced Programmable Interrupt Controller
355 Change the output verbosity whilst booting
356 Format: { quiet (default) | verbose | debug }
357 Change the amount of debugging information output
358 when initialising the APIC and IO-APIC components.
360 apm= [APM] Advanced Power Management
361 See header of arch/x86/kernel/apm_32.c.
363 arcrimi= [HW,NET] ARCnet - "RIM I" (entirely mem-mapped) cards
364 Format: <io>,<irq>,<nodeID>
368 atarimouse= [HW,MOUSE] Atari Mouse
370 atascsi= [HW,SCSI] Atari SCSI
372 atkbd.extra= [HW] Enable extra LEDs and keys on IBM RapidAccess,
373 EzKey and similar keyboards
375 atkbd.reset= [HW] Reset keyboard during initialization
377 atkbd.set= [HW] Select keyboard code set
378 Format: <int> (2 = AT (default), 3 = PS/2)
380 atkbd.scroll= [HW] Enable scroll wheel on MS Office and similar
383 atkbd.softraw= [HW] Choose between synthetic and real raw mode
384 Format: <bool> (0 = real, 1 = synthetic (default))
386 atkbd.softrepeat= [HW]
387 Use software keyboard repeat
391 baycom_epp= [HW,AX25]
394 baycom_par= [HW,AX25] BayCom Parallel Port AX.25 Modem
396 See header of drivers/net/hamradio/baycom_par.c.
398 baycom_ser_fdx= [HW,AX25]
399 BayCom Serial Port AX.25 Modem (Full Duplex Mode)
400 Format: <io>,<irq>,<mode>[,<baud>]
401 See header of drivers/net/hamradio/baycom_ser_fdx.c.
403 baycom_ser_hdx= [HW,AX25]
404 BayCom Serial Port AX.25 Modem (Half Duplex Mode)
405 Format: <io>,<irq>,<mode>
406 See header of drivers/net/hamradio/baycom_ser_hdx.c.
408 boot_delay= Milliseconds to delay each printk during boot.
409 Values larger than 10 seconds (10000) are changed to
413 bootmem_debug [KNL] Enable bootmem allocator debug messages.
415 bttv.card= [HW,V4L] bttv (bt848 + bt878 based grabber cards)
416 bttv.radio= Most important insmod options are available as
418 bttv.pll= See Documentation/video4linux/bttv/Insmod-options
419 bttv.tuner= and Documentation/video4linux/bttv/CARDLIST
422 See drivers/scsi/BusLogic.c, comment before function
423 BusLogic_ParseDriverOptions().
425 c101= [NET] Moxa C101 synchronous serial card
427 cachesize= [BUGS=X86-32] Override level 2 CPU cache size detection.
428 Sometimes CPU hardware bugs make them report the cache
429 size incorrectly. The kernel will attempt work arounds
430 to fix known problems, but for some CPUs it is not
431 possible to determine what the correct size should be.
432 This option provides an override for these situations.
434 security= [SECURITY] Choose a security module to enable at boot.
435 If this boot parameter is not specified, only the first
436 security module asking for security registration will be
437 loaded. An invalid security module name will be treated
438 as if no module has been chosen.
441 [SECURITY] Disable capabilities. This would normally
442 be used only if an alternative security model is to be
443 configured. Potentially dangerous and should only be
444 used if you are entirely sure of the consequences.
446 ccw_timeout_log [S390]
447 See Documentation/s390/CommonIO for details.
449 cgroup_disable= [KNL] Disable a particular controller
450 Format: {name of the controller(s) to disable}
451 {Currently supported controllers - "memory"}
453 checkreqprot [SELINUX] Set initial checkreqprot flag value.
454 Format: { "0" | "1" }
455 See security/selinux/Kconfig help text.
456 0 -- check protection applied by kernel (includes
457 any implied execute protection).
458 1 -- check protection requested by application.
459 Default value is set via a kernel config option.
460 Value can be changed at runtime via
461 /selinux/checkreqprot.
464 See Documentation/s390/CommonIO for details.
466 clock= [BUGS=X86-32, HW] gettimeofday clocksource override.
468 Forces specified clocksource (if available) to be used
469 when calculating gettimeofday(). If specified
470 clocksource is not available, it defaults to PIT.
471 Format: { pit | tsc | cyclone | pmtmr }
473 clocksource= [GENERIC_TIME] Override the default clocksource
475 Override the default clocksource and use the clocksource
476 with the name specified.
477 Some clocksource names to choose from, depending on
479 [all] jiffies (this is the base, fallback clocksource)
481 [ARM] imx_timer1,OSTS,netx_timer,mpu_timer2,
482 pxa_timer,timer3,32k_counter,timer0_1
484 [X86-32] pit,hpet,tsc,vmi-timer;
485 scx200_hrt on Geode; cyclone on IBM x440
493 clearcpuid=BITNUM [X86]
494 Disable CPUID feature X for the kernel. See
495 include/asm-x86/cpufeature.h for the valid bit numbers.
496 Note the Linux specific bits are not necessarily
497 stable over kernel options, but the vendor specific
499 Also note that user programs calling CPUID directly
500 or using the feature without checking anything
501 will still see it. This just prevents it from
502 being used by the kernel or shown in /proc/cpuinfo.
503 Also note the kernel might malfunction if you disable
506 code_bytes [IA32/X86_64] How many bytes of object code to print
511 hpet= [X86-32,HPET] option to control HPET usage
512 Format: { enable (default) | disable | force }
513 disable: disable HPET and use PIT instead
514 force: allow force enabled of undocumented chips (ICH4,
517 com20020= [HW,NET] ARCnet - COM20020 chipset
519 <io>[,<irq>[,<nodeID>[,<backplane>[,<ckp>[,<timeout>]]]]]
521 com90io= [HW,NET] ARCnet - COM90xx chipset (IO-mapped buffers)
525 ARCnet - COM90xx chipset (memory-mapped buffers)
526 Format: <io>[,<irq>[,<memstart>]]
528 condev= [HW,S390] console device
531 console= [KNL] Output console device and options.
533 tty<n> Use the virtual console device <n>.
537 Use the specified serial port. The options are of
538 the form "bbbbpnf", where "bbbb" is the baud rate,
539 "p" is parity ("n", "o", or "e"), "n" is number of
540 bits, and "f" is flow control ("r" for RTS or
541 omit it). Default is "9600n8".
543 See Documentation/serial-console.txt for more
545 Documentation/networking/netconsole.txt for an
548 uart[8250],io,<addr>[,options]
549 uart[8250],mmio,<addr>[,options]
550 Start an early, polled-mode console on the 8250/16550
551 UART at the specified I/O port or MMIO address,
552 switching to the matching ttyS device later. The
553 options are the same as for ttyS, above.
555 If the device connected to the port is not a TTY but a braille
556 device, prepend "brl," before the device type, for instance
558 For now, only VisioBraille is supported.
560 earlycon= [KNL] Output early console device and options.
561 uart[8250],io,<addr>[,options]
562 uart[8250],mmio,<addr>[,options]
563 Start an early, polled-mode console on the 8250/16550
564 UART at the specified I/O port or MMIO address.
565 The options are the same as for ttyS, above.
568 [HW] Never suspend the console
569 Disable suspending of consoles during suspend and
570 hibernate operations. Once disabled, debugging
571 messages can reach various consoles while the rest
572 of the system is being put to sleep (ie, while
573 debugging driver suspend/resume hooks). This may
574 not work reliably with all consoles, but is known
575 to work with serial and VGA consoles.
577 cpcihp_generic= [HW,PCI] Generic port I/O CompactPCI driver
579 <first_slot>,<last_slot>,<port>,<enum_bit>[,<debug>]
581 crashkernel=nn[KMG]@ss[KMG]
582 [KNL] Reserve a chunk of physical memory to
583 hold a kernel to switch to with kexec on panic.
585 crashkernel=range1:size1[,range2:size2,...][@offset]
586 [KNL] Same as above, but depends on the memory
587 in the running system. The syntax of range is
588 start-[end] where start and end are both
589 a memory unit (amount[KMG]). See also
590 Documentation/kdump/kdump.txt for a example.
593 Format: <io>,<irq>,<dma>,<dma2>,<mpuio>,<mpuirq>
598 cs89x0_media= [HW,NET]
599 Format: { rj45 | aui | bnc }
602 See header of drivers/s390/block/dasd_devmap.c.
604 db9.dev[2|3]= [HW,JOY] Multisystem joystick support via parallel port
605 (one device per port)
606 Format: <port#>,<type>
607 See also Documentation/input/joystick-parport.txt
609 debug [KNL] Enable kernel debugging (events log level).
612 [KNL] verbose self-tests
614 Print debugging info while doing the locking API
616 We default to 0 (no extra messages), setting it to
617 1 will print _a lot_ more information - normally
618 only useful to kernel developers.
620 debug_objects [KNL] Enable object debugging
622 debugpat [X86] Enable PAT debugging
624 decnet.addr= [HW,NET]
625 Format: <area>[,<node>]
626 See also Documentation/networking/decnet.txt.
629 Format: <blue0>,<blue1>,<blue2>,...,<blue15>
630 Change the default blue palette of the console.
631 This is a 16-member array composed of values
635 Format: <green0>,<green1>,<green2>,...,<green15>
636 Change the default green palette of the console.
637 This is a 16-member array composed of values
641 Format: <red0>,<red1>,<red2>,...,<red15>
642 Change the default red palette of the console.
643 This is a 16-member array composed of values
649 Set system-wide default UTF-8 mode for all tty's.
650 Default is 1, i.e. UTF-8 mode is enabled for all
651 newly opened terminals.
654 Set number of hash buckets for dentry cache.
657 IO parameters + enable/disable command.
659 digiepca= [HW,SERIAL]
660 See drivers/char/README.epca and
661 Documentation/digiepca.txt.
663 disable_mtrr_cleanup [X86]
664 enable_mtrr_cleanup [X86]
665 The kernel tries to adjust MTRR layout from continuous
666 to discrete, to make X server driver able to add WB
667 entry later. This parameter enables/disables that.
669 mtrr_chunk_size=nn[KMG] [X86]
670 used for mtrr cleanup. It is largest continous chunk
671 that could hold holes aka. UC entries.
673 mtrr_gran_size=nn[KMG] [X86]
674 Used for mtrr cleanup. It is granularity of mtrr block.
676 Large value could prevent small alignment from
679 mtrr_spare_reg_nr=n [X86]
681 Range: 0,7 : spare reg number
683 Used for mtrr cleanup. It is spare mtrr entries number.
684 Set to 2 or more if your graphical card needs more.
686 disable_mtrr_trim [X86, Intel and AMD only]
687 By default the kernel will trim any uncacheable
688 memory out of your available memory pool based on
689 MTRR settings. This parameter disables that behavior,
690 possibly causing your machine to run very slowly.
692 dmasound= [HW,OSS] Sound subsystem buffers
698 earlyprintk= [X86-32,X86-64,SH,BLACKFIN]
700 earlyprintk=serial[,ttySn[,baudrate]]
703 Append ",keep" to not disable it when the real console
706 Only vga or serial or usb debug port at a time.
708 Currently only ttyS0 and ttyS1 are supported.
710 Interaction with the standard serial driver is not
713 The VGA output is eventually overwritten by the real
719 Format: {"off" | "on" | "skip[mbr]"}
721 eisa_irq_edge= [PARISC,HW]
722 See header of drivers/parisc/eisa.c.
725 See comment before function elanfreq_setup() in
726 arch/x86/kernel/cpu/cpufreq/elanfreq.c.
729 Format: {"anticipatory" | "cfq" | "deadline" | "noop"}
730 See Documentation/block/as-iosched.txt and
731 Documentation/block/deadline-iosched.txt for details.
733 elfcorehdr= [IA64,PPC,SH,X86-32,X86_64]
734 Specifies physical address of start of kernel core
735 image elf header. Generally kexec loader will
736 pass this option to capture kernel.
737 See Documentation/kdump/kdump.txt for details.
739 enforcing [SELINUX] Set initial enforcing status.
741 See security/selinux/Kconfig help text.
742 0 -- permissive (log only, no denials).
743 1 -- enforcing (deny and log).
745 Value can be changed at runtime via /selinux/enforce.
748 Format: <spdif>,[<nomix>,[<amplifier>]]
749 See also header of sound/oss/es1371.c.
751 ether= [HW,NET] Ethernet cards parameters
752 This option is obsoleted by the "netdev=" option, which
753 has equivalent usage. See its documentation for details.
755 eurwdt= [HW,WDT] Eurotech CPU-1220/1410 onboard watchdog.
760 fail_make_request=[KNL]
761 General fault injection mechanism.
762 Format: <interval>,<probability>,<space>,<times>
763 See also /Documentation/fault-injection/.
766 See header of drivers/scsi/fd_mcs.c.
769 See header of drivers/scsi/fdomain.c.
772 See Documentation/floppy.txt.
774 force_pal_cache_flush
775 [IA-64] Avoid check_sal_cache_flush which may hang on
776 buggy SAL_CACHE_FLUSH implementations. Using this
777 parameter will force ia64_sal_cache_flush to call
778 ia64_pal_cache_flush instead of SAL_CACHE_FLUSH.
781 [HW,JOY] Multisystem joystick and NES/SNES/PSX pad
782 support via parallel port (up to 5 devices per port)
783 Format: <port#>,<pad1>,<pad2>,<pad3>,<pad4>,<pad5>
784 See also Documentation/input/joystick-parport.txt
788 gart_fix_e820= [X86_64] disable the fix e820 for K8 GART
793 See header of drivers/scsi/gdth.c.
795 gpt [EFI] Forces disk with valid GPT signature but
796 invalid Protective MBR to be treated as GPT.
800 hashdist= [KNL,NUMA] Large hashes allocated during boot
801 are distributed across NUMA nodes. Defaults on
802 for IA-64, off otherwise.
803 Format: 0 | 1 (for off | on)
805 hcl= [IA-64] SGI's Hardware Graph compatibility layer
807 hd= [EIDE] (E)IDE hard drive subsystem geometry
808 Format: <cyl>,<head>,<sect>
810 highmem=nn[KMG] [KNL,BOOT] forces the highmem zone to have an exact
811 size of <nn>. This works even on boxes that have no
812 highmem otherwise. This also works to reduce highmem
813 size on bigger boxes.
815 highres= [KNL] Enable/disable high resolution timer mode.
816 Valid parameters: "on", "off"
820 See Documentation/isdn/README.HiSax.
822 hugepages= [HW,X86-32,IA-64] HugeTLB pages to allocate at boot.
823 hugepagesz= [HW,IA-64,PPC,X86-64] The size of the HugeTLB pages.
824 On x86-64 and powerpc, this option can be specified
825 multiple times interleaved with hugepages= to reserve
826 huge pages of different sizes. Valid pages sizes on
827 x86-64 are 2M (when the CPU supports "pse") and 1G
828 (when the CPU supports the "pdpe1gb" cpuinfo flag)
829 Note that 1GB pages can only be allocated at boot time
830 using hugepages= and not freed afterwards.
832 [same as hugepagesz=] The size of the default
833 HugeTLB page size. This is the size represented by
834 the legacy /proc/ hugepages APIs, used for SHM, and
835 default size when mounting hugetlbfs filesystems.
836 Defaults to the default architecture's huge page size
841 i8042.debug [HW] Toggle i8042 debug mode
842 i8042.direct [HW] Put keyboard port into non-translated mode
843 i8042.dumbkbd [HW] Pretend that controller can only read data from
844 keyboard and cannot control its state
845 (Don't attempt to blink the leds)
846 i8042.noaux [HW] Don't check for auxiliary (== mouse) port
847 i8042.nokbd [HW] Don't check/create keyboard port
848 i8042.noloop [HW] Disable the AUX Loopback command while probing
850 i8042.nomux [HW] Don't check presence of an active multiplexing
852 i8042.nopnp [HW] Don't use ACPIPnP / PnPBIOS to discover KBD/AUX
855 [HW] Frequency with which keyboard LEDs should blink
856 when kernel panics (default is 0.5 sec)
857 i8042.reset [HW] Reset the controller during init and cleanup
858 i8042.unlock [HW] Unlock (ignore) the keylock
862 i8k.ignore_dmi [HW] Continue probing hardware even if DMI data
863 indicates that the driver is running on unsupported
865 i8k.force [HW] Activate i8k driver even if SMM BIOS signature
866 does not match list of supported models.
868 [HW] Report power status in /proc/i8k
869 (disabled by default)
870 i8k.restricted [HW] Allow controlling fans only if SYS_ADMIN
873 ibmmcascsi= [HW,MCA,SCSI] IBM MicroChannel SCSI adapter
874 See Documentation/mca.txt.
877 Format: <io>[,<membase>[,<icn_id>[,<icn_id2>]]]
879 ide= [HW] (E)IDE subsystem
880 Format: ide=nodma or ide=doubler
881 See Documentation/ide/ide.txt.
883 idebus= [HW] (E)IDE subsystem - VLB/PCI bus speed
884 See Documentation/ide/ide.txt.
887 Format: idle=poll or idle=mwait, idle=halt, idle=nomwait
888 Poll forces a polling idle loop that can slightly improves the performance
889 of waking up a idle CPU, but will use a lot of power and make the system
890 run hot. Not recommended.
891 idle=mwait. On systems which support MONITOR/MWAIT but the kernel chose
892 to not use it because it doesn't save as much power as a normal idle
893 loop use the MONITOR/MWAIT idle loop anyways. Performance should be the same
895 idle=halt. Halt is forced to be used for CPU idle.
896 In such case C2/C3 won't be used again.
897 idle=nomwait. Disable mwait for CPU C-states
899 ide-pci-generic.all-generic-ide [HW] (E)IDE subsystem
900 Claim all unknown PCI IDE storage controllers.
902 ignore_loglevel [KNL]
903 Ignore loglevel setting - this will print /all/
904 kernel messages to the console. Useful for debugging.
907 Set number of hash buckets for inode cache.
910 See header of drivers/scsi/in2000.c.
914 Run specified binary instead of /sbin/init as init
917 initcall_debug [KNL] Trace initcalls as they are executed. Useful
918 for working out where the kernel is dying during
921 initrd= [BOOT] Specify the location of the initial ramdisk
923 inport.irq= [HW] Inport (ATI XL and Microsoft) busmouse driver
941 intel_iommu= [DMAR] Intel IOMMU driver (DMAR) option
943 Disable intel iommu driver.
944 igfx_off [Default Off]
945 By default, gfx is mapped as normal device. If a gfx
946 device has a dedicated DMAR unit, the DMAR unit is
947 bypassed by not enabling DMAR with this option. In
948 this case, gfx device will use physical address for
951 With this option iommu will not optimize to look
952 for io virtual address below 32 bit forcing dual
953 address cycle on pci bus for cards supporting greater
954 than 32 bit addressing. The default is to look
955 for translation below 32 bit and if not available
956 then look in the higher range.
958 With this option on every unmap_single operation will
959 result in a hardware IOTLB flush operation as opposed
960 to batching them for performance.
962 io_delay= [X86-32,X86-64] I/O delay method
964 Standard port 0x80 based delay
966 Alternate port 0xed based delay (needed on some systems)
968 Simple two microseconds delay
972 io7= [HW] IO7 for Marvel based alpha systems
973 See comment before marvel_specify_io7 in
974 arch/alpha/kernel/core_marvel.c.
977 See Documentation/filesystems/nfsroot.txt.
979 ip2= [HW] Set IO/IRQ pairs for up to 4 IntelliPort boards
980 See comment before ip2_setup() in
981 drivers/char/ip2/ip2base.c.
983 ips= [HW,SCSI] Adaptec / IBM ServeRAID controller
984 See header of drivers/scsi/ips.c.
986 ports= [IP_VS_FTP] IPVS ftp helper module
988 Up to 8 (IP_VS_APP_MAX_PORTS) ports
990 Format: <port>,<port>....
993 When an interrupt is not handled search all handlers
994 for it. Intended to get systems with badly broken
998 When an interrupt is not handled search all handlers
999 for it. Also check all handlers each timer
1000 interrupt. Intended to get systems with badly broken
1004 Format: <RDP>,<reset>,<pci_scan>,<verbosity>
1006 isolcpus= [KNL,SMP] Isolate CPUs from the general scheduler.
1008 <cpu number>,...,<cpu number>
1010 <cpu number>-<cpu number>
1011 (must be a positive range in ascending order)
1013 <cpu number>,...,<cpu number>-<cpu number>
1015 This option can be used to specify one or more CPUs
1016 to isolate from the general SMP balancing and scheduling
1017 algorithms. You can move a process onto or off an
1018 "isolated" CPU via the CPU affinity syscalls or cpuset.
1019 <cpu number> begins at 0 and the maximum value is
1020 "number of CPUs in system - 1".
1022 This option is the preferred way to isolate CPUs. The
1023 alternative -- manually setting the CPU mask of all
1024 tasks in the system -- can cause problems and
1025 suboptimal load balancer performance.
1029 js= [HW,JOY] Analog joystick
1030 See Documentation/input/joystick.txt.
1032 kernelcore=nn[KMG] [KNL,X86-32,IA-64,PPC,X86-64] This parameter
1033 specifies the amount of memory usable by the kernel
1034 for non-movable allocations. The requested amount is
1035 spread evenly throughout all nodes in the system. The
1036 remaining memory in each node is used for Movable
1037 pages. In the event, a node is too small to have both
1038 kernelcore and Movable pages, kernelcore pages will
1039 take priority and other nodes will have a larger number
1040 of kernelcore pages. The Movable zone is used for the
1041 allocation of pages that may be reclaimed or moved
1042 by the page migration subsystem. This means that
1043 HugeTLB pages may not be allocated from this zone.
1044 Note that allocations like PTEs-from-HighMem still
1045 use the HighMem zone if it exists, and the Normal
1046 zone if it does not.
1048 movablecore=nn[KMG] [KNL,X86-32,IA-64,PPC,X86-64] This parameter
1049 is similar to kernelcore except it specifies the
1050 amount of memory used for migratable allocations.
1051 If both kernelcore and movablecore is specified,
1052 then kernelcore will be at *least* the specified
1053 value but may be more. If movablecore on its own
1054 is specified, the administrator must be careful
1055 that the amount of memory usable for all allocations
1060 kstack=N [X86-32,X86-64] Print N words from the kernel stack
1063 kgdboc= [HW] kgdb over consoles.
1064 Requires a tty driver that supports console polling.
1065 (only serial suported for now)
1066 Format: <serial_device>[,baud]
1068 kmac= [MIPS] korina ethernet MAC address.
1069 Configure the RouterBoard 532 series on-chip
1070 Ethernet adapter MAC address.
1076 lapic [X86-32,APIC] Enable the local APIC even if BIOS
1079 lapic_timer_c2_ok [X86-32,x86-64,APIC] trust the local apic timer in
1082 libata.dma= [LIBATA] DMA control
1083 libata.dma=0 Disable all PATA and SATA DMA
1084 libata.dma=1 PATA and SATA Disk DMA only
1085 libata.dma=2 ATAPI (CDROM) DMA only
1086 libata.dma=4 Compact Flash DMA only
1087 Combinations also work, so libata.dma=3 enables DMA
1088 for disks and CDROMs, but not CFs.
1090 libata.noacpi [LIBATA] Disables use of ACPI in libata suspend/resume
1094 libata.force= [LIBATA] Force configurations. The format is comma
1095 separated list of "[ID:]VAL" where ID is
1096 PORT[:DEVICE]. PORT and DEVICE are decimal numbers
1097 matching port, link or device. Basically, it matches
1098 the ATA ID string printed on console by libata. If
1099 the whole ID part is omitted, the last PORT and DEVICE
1100 values are used. If ID hasn't been specified yet, the
1101 configuration applies to all ports, links and devices.
1103 If only DEVICE is omitted, the parameter applies to
1104 the port and all links and devices behind it. DEVICE
1105 number of 0 either selects the first device or the
1106 first fan-out link behind PMP device. It does not
1107 select the host link. DEVICE number of 15 selects the
1108 host link and device attached to it.
1110 The VAL specifies the configuration to force. As long
1111 as there's no ambiguity shortcut notation is allowed.
1112 For example, both 1.5 and 1.5G would work for 1.5Gbps.
1113 The following configurations can be forced.
1115 * Cable type: 40c, 80c, short40c, unk, ign or sata.
1116 Any ID with matching PORT is used.
1118 * SATA link speed limit: 1.5Gbps or 3.0Gbps.
1120 * Transfer mode: pio[0-7], mwdma[0-4] and udma[0-7].
1121 udma[/][16,25,33,44,66,100,133] notation is also
1124 * [no]ncq: Turn on or off NCQ.
1126 * nohrst, nosrst, norst: suppress hard, soft
1129 If there are multiple matching configurations changing
1130 the same attribute, the last one is used.
1132 load_ramdisk= [RAM] List of ramdisks to load from floppy
1133 See Documentation/ramdisk.txt.
1135 lockd.nlm_grace_period=P [NFS] Assign grace period.
1138 lockd.nlm_tcpport=N [NFS] Assign TCP port.
1141 lockd.nlm_timeout=T [NFS] Assign timeout value.
1144 lockd.nlm_udpport=M [NFS] Assign UDP port.
1147 logibm.irq= [HW,MOUSE] Logitech Bus Mouse Driver
1150 loglevel= All Kernel Messages with a loglevel smaller than the
1151 console loglevel will be printed to the console. It can
1152 also be changed with klogd or other programs. The
1153 loglevels are defined as follows:
1155 0 (KERN_EMERG) system is unusable
1156 1 (KERN_ALERT) action must be taken immediately
1157 2 (KERN_CRIT) critical conditions
1158 3 (KERN_ERR) error conditions
1159 4 (KERN_WARNING) warning conditions
1160 5 (KERN_NOTICE) normal but significant condition
1161 6 (KERN_INFO) informational
1162 7 (KERN_DEBUG) debug-level messages
1164 log_buf_len=n Sets the size of the printk ring buffer, in bytes.
1165 Format: { n | nk | nM }
1166 n must be a power of two. The default size
1167 is set in the kernel config file.
1169 logo.nologo [FB] Disables display of the built-in Linux logo.
1170 This may be used to provide more screen space for
1171 kernel log messages and is useful when debugging
1172 kernel boot problems.
1174 lp=0 [LP] Specify parallel ports to use, e.g,
1175 lp=port[,port...] lp=none,parport0 (lp0 not configured, lp1 uses
1176 lp=reset first parallel port). 'lp=0' disables the
1177 lp=auto printer driver. 'lp=reset' (which can be
1178 specified in addition to the ports) causes
1179 attached printers to be reset. Using
1180 lp=port1,port2,... specifies the parallel ports
1181 to associate lp devices with, starting with
1182 lp0. A port specification may be 'none' to skip
1183 that lp device, or a parport name such as
1184 'parport0'. Specifying 'lp=auto' instead of a
1185 port specification list means that device IDs
1186 from each port should be examined, to see if
1187 an IEEE 1284-compliant printer is attached; if
1188 so, the driver will manage that printer.
1189 See also header of drivers/char/lp.c.
1192 Sets loops_per_jiffy to given constant, thus avoiding
1193 time-consuming boot-time autodetection (up to 250 ms per
1194 CPU). 0 enables autodetection (default). To determine
1195 the correct value for your kernel, boot with normal
1196 autodetection and see what value is printed. Note that
1197 on SMP systems the preset will be applied to all CPUs,
1198 which is likely to cause problems if your CPUs need
1199 significantly divergent settings. An incorrect value
1200 will cause delays in the kernel to be wrong, leading to
1201 unpredictable I/O errors and other breakage. Although
1202 unlikely, in the extreme case this might damage your
1206 Format: <io>,<irq>,<dma>
1208 mac5380= [HW,SCSI] Format:
1209 <can_queue>,<cmd_per_lun>,<sg_tablesize>,<hostid>,<use_tags>
1211 machvec= [IA64] Force the use of a particular machine-vector
1212 (machvec) in a generic kernel.
1213 Example: machvec=hpzx1_swiotlb
1215 max_loop= [LOOP] Maximum number of loopback devices that can
1219 maxcpus= [SMP] Maximum number of processors that an SMP kernel
1220 should make use of. maxcpus=n : n >= 0 limits the
1221 kernel to using 'n' processors. n=0 is a special case,
1222 it is equivalent to "nosmp", which also disables
1225 max_addr=[KMG] [KNL,BOOT,ia64] All physical memory greater than or
1226 equal to this physical address is ignored.
1228 max_luns= [SCSI] Maximum number of LUNs to probe.
1229 Should be between 1 and 2^32-1.
1232 [SCSI] Maximum number of LUNs received.
1233 Should be between 1 and 16384.
1237 mce [X86-32] Machine Check Exception
1239 mce=option [X86-64] See Documentation/x86/x86_64/boot-options.txt
1241 md= [HW] RAID subsystems devices and level
1242 See Documentation/md.txt.
1245 Format: <first>,<last>
1246 Specifies range of consoles to be captured by the MDA.
1248 mem=nn[KMG] [KNL,BOOT] Force usage of a specific amount of memory
1249 Amount of memory to be used when the kernel is not able
1250 to see the whole system memory or for test.
1251 [X86-32] Use together with memmap= to avoid physical
1252 address space collisions. Without memmap= PCI devices
1253 could be placed at addresses belonging to unused RAM.
1255 mem=nopentium [BUGS=X86-32] Disable usage of 4MB pages for kernel
1259 [KNL,SH] Allow user to override the default size for
1260 per-device physically contiguous DMA buffers.
1262 memmap=exactmap [KNL,X86-32,X86_64] Enable setting of an exact
1263 E820 memory map, as specified by the user.
1264 Such memmap=exactmap lines can be constructed based on
1265 BIOS output or other requirements. See the memmap=nn@ss
1268 memmap=nn[KMG]@ss[KMG]
1269 [KNL] Force usage of a specific region of memory
1270 Region of memory to be used, from ss to ss+nn.
1272 memmap=nn[KMG]#ss[KMG]
1273 [KNL,ACPI] Mark specific memory as ACPI data.
1274 Region of memory to be used, from ss to ss+nn.
1276 memmap=nn[KMG]$ss[KMG]
1277 [KNL,ACPI] Mark specific memory as reserved.
1278 Region of memory to be used, from ss to ss+nn.
1279 Example: Exclude memory from 0x18690000-0x1869ffff
1280 memmap=64K$0x18690000
1282 memmap=0x10000$0x18690000
1284 memory_corruption_check=0/1 [X86]
1285 Some BIOSes seem to corrupt the first 64k of
1286 memory when doing things like suspend/resume.
1287 Setting this option will scan the memory
1288 looking for corruption. Enabling this will
1289 both detect corruption and prevent the kernel
1290 from using the memory being corrupted.
1291 However, its intended as a diagnostic tool; if
1292 repeatable BIOS-originated corruption always
1293 affects the same memory, you can use memmap=
1294 to prevent the kernel from using that memory.
1296 memory_corruption_check_size=size [X86]
1297 By default it checks for corruption in the low
1298 64k, making this memory unavailable for normal
1299 use. Use this parameter to scan for
1300 corruption in more or less memory.
1302 memory_corruption_check_period=seconds [X86]
1303 By default it checks for corruption every 60
1304 seconds. Use this parameter to check at some
1305 other rate. 0 disables periodic checking.
1307 memtest= [KNL,X86] Enable memtest
1309 range: 0,4 : pattern number
1310 default : 0 <disable>
1312 meye.*= [HW] Set MotionEye Camera parameters
1313 See Documentation/video4linux/meye.txt.
1315 mfgpt_irq= [IA-32] Specify the IRQ to use for the
1316 Multi-Function General Purpose Timers on AMD Geode
1319 mfgptfix [X86-32] Fix MFGPT timers on AMD Geode platforms when
1320 the BIOS has incorrectly applied a workaround. TinyBIOS
1321 version 0.98 is known to be affected, 0.99 fixes the
1322 problem by letting the user disable the workaround.
1327 [KNL] When CONFIG_DEBUG_MEMORY_INIT is set, this
1328 parameter allows control of the logging verbosity for
1329 the additional memory initialisation checks. A value
1330 of 0 disables mminit logging and a level of 4 will
1331 log everything. Information is printed at KERN_DEBUG
1332 so loglevel=8 may also need to be specified.
1335 [MOUSE] Maximum time between finger touching and
1336 leaving touchpad surface for touch to be considered
1337 a tap and be reported as a left button click (for
1338 touchpads working in absolute mode only).
1340 mousedev.xres= [MOUSE] Horizontal screen resolution, used for devices
1341 reporting absolute coordinates, such as tablets
1342 mousedev.yres= [MOUSE] Vertical screen resolution, used for devices
1343 reporting absolute coordinates, such as tablets
1348 MTD_Partition= [MTD]
1349 Format: <name>,<region-number>,<size>,<offset>
1351 MTD_Region= [MTD] Format:
1352 <name>,<region-number>[,<base>,<size>,<buswidth>,<altbuswidth>]
1355 See drivers/mtd/cmdlinepart.c.
1358 ARM/S3C2412 JIVE boot control
1360 See arch/arm/mach-s3c2412/mach-jive.c
1362 mtouchusb.raw_coordinates=
1363 [HW] Make the MicroTouch USB driver use raw coordinates
1364 ('y', default) or cooked coordinates ('n')
1366 n2= [NET] SDL Inc. RISCom/N2 synchronous serial card
1369 See header of drivers/scsi/NCR_D700.c.
1373 ncr53c400= [HW,SCSI]
1375 ncr53c400a= [HW,SCSI]
1377 ncr53c406a= [HW,SCSI]
1379 ncr53c8xx= [HW,SCSI]
1381 netdev= [NET] Network devices parameters
1382 Format: <irq>,<io>,<mem_start>,<mem_end>,<name>
1383 Note that mem_start is often overloaded to mean
1384 something different and driver-specific.
1385 This usage is only documented in each driver source
1389 [NETFILTER] Enable connection tracking flow accounting
1390 0 to disable accounting
1391 1 to enable accounting
1392 Default value depends on CONFIG_NF_CT_ACCT that is
1393 going to be removed in 2.6.29.
1396 See Documentation/filesystems/nfsroot.txt.
1398 nfsroot= [NFS] nfs root filesystem for disk-less boxes.
1399 See Documentation/filesystems/nfsroot.txt.
1401 nfs.callback_tcpport=
1402 [NFS] set the TCP port on which the NFSv4 callback
1403 channel should listen.
1405 nfs.idmap_cache_timeout=
1406 [NFS] set the maximum lifetime for idmapper cache
1410 [NFS] enable 64-bit inode numbers.
1411 If zero, the NFS client will fake up a 32-bit inode
1412 number for the readdir() and stat() syscalls instead
1413 of returning the full 64-bit number.
1414 The default is to return 64-bit inode numbers.
1416 nmi_debug= [KNL,AVR32] Specify one or more actions to take
1417 when a NMI is triggered.
1418 Format: [state][,regs][,debounce][,die]
1420 nmi_watchdog= [KNL,BUGS=X86-32] Debugging features for SMP kernels
1422 no387 [BUGS=X86-32] Tells the kernel to use the 387 maths
1423 emulation library even if a 387 maths coprocessor
1426 noaliencache [MM, NUMA, SLAB] Disables the allocation of alien
1427 caches in the slab allocator. Saves per-node memory,
1428 but will impact performance.
1432 noapic [SMP,APIC] Tells the kernel to not make use of any
1433 IOAPICs that may be present in the system.
1435 nobats [PPC] Do not use BATs for mapping kernel lowmem
1436 on "Classic" PPC cores.
1440 nodelayacct [KNL] Disable per-task delay accounting
1442 nodisconnect [HW,SCSI,M68K] Disables SCSI disconnects.
1444 nodsp [SH] Disable hardware DSP at boot time.
1446 noefi [X86-32,X86-64] Disable EFI runtime services support.
1450 noexec [X86-32,X86-64]
1451 On X86-32 available only on PAE configured kernels.
1452 noexec=on: enable non-executable mappings (default)
1453 noexec=off: disable non-executable mappings
1456 This affects only 32-bit executables.
1457 noexec32=on: enable non-executable mappings (default)
1458 read doesn't imply executable mappings
1459 noexec32=off: disable non-executable mappings
1460 read implies executable mappings
1462 nofpu [SH] Disable hardware FPU at boot time.
1464 nofxsr [BUGS=X86-32] Disables x86 floating point extended
1465 register save and restore. The kernel will only save
1466 legacy floating-point registers on task switch.
1468 noclflush [BUGS=X86] Don't use the CLFLUSH instruction
1472 no-hlt [BUGS=X86-32] Tells the kernel that the hlt
1473 instruction doesn't work correctly and not to
1476 nohalt [IA-64] Tells the kernel not to use the power saving
1477 function PAL_HALT_LIGHT when idle. This increases
1478 power-consumption. On the positive side, it reduces
1479 interrupt wake-up latency, which may improve performance
1480 in certain environments such as networked servers or
1483 nohz= [KNL] Boottime enable/disable dynamic ticks
1484 Valid arguments: on, off
1487 noirqdebug [X86-32] Disables the code which attempts to detect and
1488 disable unhandled interrupt sources.
1490 no_timer_check [X86-32,X86_64,APIC] Disables the code which tests for
1491 broken timer IRQ sources.
1493 noisapnp [ISAPNP] Disables ISA PnP code.
1495 noinitrd [RAM] Tells the kernel not to load any configured
1500 nojitter [IA64] Disables jitter checking for ITC timers.
1502 nolapic [X86-32,APIC] Do not enable or use the local APIC.
1504 nolapic_timer [X86-32,APIC] Do not use the local APIC timer.
1506 nox2apic [X86-64,APIC] Do not enable x2APIC mode.
1508 x2apic_phys [X86-64,APIC] Use x2apic physical mode instead of
1509 default x2apic cluster mode on platforms
1512 noltlbs [PPC] Do not use large page/tlb entries for kernel
1513 lowmem mapping on PPC40x.
1515 nomca [IA-64] Disable machine check abort handling
1517 nomce [X86-32] Machine Check Exception
1519 nomfgpt [X86-32] Disable Multi-Function General Purpose
1520 Timer usage (for AMD Geode machines).
1522 noreplace-paravirt [X86-32,PV_OPS] Don't patch paravirt_ops
1524 noreplace-smp [X86-32,SMP] Don't replace SMP instructions
1525 with UP alternatives
1527 noresidual [PPC] Don't use residual data on PReP machines.
1529 noresume [SWSUSP] Disables resume and restores original swap
1532 no-scroll [VGA] Disables scrollback.
1533 This is required for the Braillex ib80-piezo Braille
1534 reader made by F.H. Papenmeier (Germany).
1538 nosep [BUGS=X86-32] Disables x86 SYSENTER/SYSEXIT support.
1540 nosmp [SMP] Tells an SMP kernel to act as a UP kernel,
1541 and disable the IO APIC. legacy for "maxcpus=0".
1543 nosoftlockup [KNL] Disable the soft-lockup detector.
1545 nosync [HW,M68K] Disables sync negotiation for all devices.
1547 notsc [BUGS=X86-32] Disable Time Stamp Counter
1549 nousb [USB] Disable the USB subsystem
1553 nptcg= [IA64] Override max number of concurrent global TLB
1554 purges which is reported from either PAL_VM_SUMMARY or
1557 numa_zonelist_order= [KNL, BOOT] Select zonelist order for NUMA.
1558 one of ['zone', 'node', 'default'] can be specified
1559 This can be set from sysctl after boot.
1560 See Documentation/sysctl/vm.txt for details.
1562 nr_uarts= [SERIAL] maximum number of UARTs to be registered.
1564 olpc_ec_timeout= [OLPC] ms delay when issuing EC commands
1565 Rather than timing out after 20 ms if an EC
1566 command is not properly ACKed, override the length
1567 of the timeout. We have interrupts disabled while
1568 waiting for the ACK, so if this is set too high
1569 interrupts *may* be lost!
1574 oprofile.timer= [HW]
1575 Use timer interrupt instead of performance counters
1577 osst= [HW,SCSI] SCSI Tape Driver
1578 Format: <buffer_size>,<write_threshold>
1579 See also Documentation/scsi/st.txt.
1581 panic= [KNL] Kernel behaviour on panic
1584 parkbd.port= [HW] Parallel port number the keyboard adapter is
1585 connected to, default is 0.
1587 parkbd.mode= [HW] Parallel port keyboard adapter mode of operation,
1588 0 for XT, 1 for AT (default is AT).
1591 parport= [HW,PPT] Specify parallel ports. 0 disables.
1592 Format: { 0 | auto | 0xBBB[,IRQ[,DMA]] }
1593 Use 'auto' to force the driver to use any
1594 IRQ/DMA settings detected (the default is to
1595 ignore detected IRQ/DMA settings because of
1596 possible conflicts). You can specify the base
1597 address, IRQ, and DMA settings; IRQ and DMA
1598 should be numbers, or 'auto' (for using detected
1599 settings on that particular port), or 'nofifo'
1600 (to avoid using a FIFO even if it is detected).
1601 Parallel ports are assigned in the order they
1602 are specified on the command line, starting
1605 parport_init_mode= [HW,PPT]
1606 Configure VIA parallel port to operate in
1607 a specific mode. This is necessary on Pegasos
1608 computer where firmware has no options for setting
1609 up parallel port mode and sets it to spp.
1610 Currently this function knows 686a and 8231 chips.
1611 Format: [spp|ps2|epp|ecp|ecpepp]
1613 pas2= [HW,OSS] Format:
1614 <io>,<irq>,<dma>,<dma16>,<sb_io>,<sb_irq>,<sb_dma>,<sb_dma16>
1617 See header of drivers/scsi/pas16.c.
1620 Halt all CPUs after the first oops has been printed for
1621 the specified number of seconds. This is to be used if
1622 your oopses keep scrolling off the screen.
1627 See header of drivers/block/paride/pcd.c.
1628 See also Documentation/paride.txt.
1630 pci=option[,option...] [PCI] various PCI subsystem options:
1631 off [X86] don't probe for the PCI bus
1632 bios [X86-32] force use of PCI BIOS, don't access
1633 the hardware directly. Use this if your machine
1634 has a non-standard PCI host bridge.
1635 nobios [X86-32] disallow use of PCI BIOS, only direct
1636 hardware access methods are allowed. Use this
1637 if you experience crashes upon bootup and you
1638 suspect they are caused by the BIOS.
1639 conf1 [X86] Force use of PCI Configuration
1641 conf2 [X86] Force use of PCI Configuration
1643 noaer [PCIE] If the PCIEAER kernel config parameter is
1644 enabled, this kernel boot option can be used to
1645 disable the use of PCIE advanced error reporting.
1646 nodomains [PCI] Disable support for multiple PCI
1647 root domains (aka PCI segments, in ACPI-speak).
1648 nommconf [X86-32,X86_64] Disable use of MMCONFIG for PCI
1650 nomsi [MSI] If the PCI_MSI kernel config parameter is
1651 enabled, this kernel boot option can be used to
1652 disable the use of MSI interrupts system-wide.
1653 biosirq [X86-32] Use PCI BIOS calls to get the interrupt
1654 routing table. These calls are known to be buggy
1655 on several machines and they hang the machine
1656 when used, but on other computers it's the only
1657 way to get the interrupt routing table. Try
1658 this option if the kernel is unable to allocate
1659 IRQs or discover secondary PCI buses on your
1661 rom [X86] Assign address space to expansion ROMs.
1662 Use with caution as certain devices share
1663 address decoders between ROMs and other
1665 norom [X86] Do not assign address space to
1666 expansion ROMs that do not already have
1667 BIOS assigned address ranges.
1668 irqmask=0xMMMM [X86] Set a bit mask of IRQs allowed to be
1669 assigned automatically to PCI devices. You can
1670 make the kernel exclude IRQs of your ISA cards
1672 pirqaddr=0xAAAAA [X86] Specify the physical address
1673 of the PIRQ table (normally generated
1674 by the BIOS) if it is outside the
1675 F0000h-100000h range.
1676 lastbus=N [X86] Scan all buses thru bus #N. Can be
1677 useful if the kernel is unable to find your
1678 secondary buses and you want to tell it
1679 explicitly which ones they are.
1680 assign-busses [X86] Always assign all PCI bus
1681 numbers ourselves, overriding
1682 whatever the firmware may have done.
1683 usepirqmask [X86] Honor the possible IRQ mask stored
1684 in the BIOS $PIR table. This is needed on
1685 some systems with broken BIOSes, notably
1686 some HP Pavilion N5400 and Omnibook XE3
1687 notebooks. This will have no effect if ACPI
1688 IRQ routing is enabled.
1689 noacpi [X86] Do not use ACPI for IRQ routing
1690 or for PCI scanning.
1691 use_crs [X86] Use _CRS for PCI resource
1693 routeirq Do IRQ routing for all PCI devices.
1694 This is normally done in pci_enable_device(),
1695 so this option is a temporary workaround
1696 for broken drivers that don't call it.
1697 skip_isa_align [X86] do not align io start addr, so can
1698 handle more pci cards
1699 firmware [ARM] Do not re-enumerate the bus but instead
1700 just use the configuration from the
1701 bootloader. This is currently used on
1702 IXP2000 systems where the bus has to be
1703 configured a certain way for adjunct CPUs.
1704 noearly [X86] Don't do any early type 1 scanning.
1705 This might help on some broken boards which
1706 machine check when some devices' config space
1707 is read. But various workarounds are disabled
1708 and some IOMMU drivers will not work.
1709 bfsort Sort PCI devices into breadth-first order.
1710 This sorting is done to get a device
1711 order compatible with older (<= 2.4) kernels.
1712 nobfsort Don't sort PCI devices into breadth-first order.
1713 cbiosize=nn[KMG] The fixed amount of bus space which is
1714 reserved for the CardBus bridge's IO window.
1715 The default value is 256 bytes.
1716 cbmemsize=nn[KMG] The fixed amount of bus space which is
1717 reserved for the CardBus bridge's memory
1718 window. The default value is 64 megabytes.
1720 pcie_aspm= [PCIE] Forcibly enable or disable PCIe Active State Power
1723 force Enable ASPM even on devices that claim not to support it.
1724 WARNING: Forcing ASPM on may cause system lockups.
1726 pcmv= [HW,PCMCIA] BadgePAD 4
1729 See Documentation/paride.txt.
1731 pdcchassis= [PARISC,HW] Disable/Enable PDC Chassis Status codes at
1734 See arch/parisc/kernel/pdc_chassis.c
1737 See Documentation/paride.txt.
1740 See Documentation/paride.txt.
1742 pirq= [SMP,APIC] Manual mp-table setup
1743 See Documentation/x86/i386/IO-APIC.txt.
1745 plip= [PPT,NET] Parallel port network link
1746 Format: { parport<nr> | timid | 0 }
1747 See also Documentation/parport.txt.
1749 pmtmr= [X86] Manual setup of pmtmr I/O Port.
1750 Override pmtimer IOPort with a hex value.
1754 Enable PNP debug messages. This depends on the
1755 CONFIG_PNP_DEBUG_MESSAGES option.
1761 { on | off | curr | res | no-curr | no-res }
1764 [ISAPNP] Exclude IRQs for the autoconfiguration
1767 [ISAPNP] Exclude DMAs for the autoconfiguration
1769 pnp_reserve_io= [ISAPNP] Exclude I/O ports for the autoconfiguration
1770 Ranges are in pairs (I/O port base and size).
1773 [ISAPNP] Exclude memory regions for the
1775 Ranges are in pairs (memory base and size).
1778 Enables pr_debug()/dev_dbg() calls if
1779 CONFIG_DYNAMIC_PRINTK_DEBUG has been enabled. These can also
1780 be switched on/off via <debugfs>/dynamic_printk/modules
1782 print-fatal-signals=
1783 [KNL] debug: print fatal signals
1784 print-fatal-signals=1: print segfault info to
1788 printk.time= Show timing data prefixed to each printk message line
1789 Format: <bool> (1/Y/y=enable, 0/N/n=disable)
1791 profile= [KNL] Enable kernel profiling via /proc/profile
1792 Format: [schedule,]<number>
1793 Param: "schedule" - profile schedule points.
1794 Param: <number> - step/bucket size as a power of 2 for
1795 statistical time based profiling.
1796 Param: "sleep" - profile D-state sleeping (millisecs).
1797 Requires CONFIG_SCHEDSTATS
1798 Param: "kvm" - profile VM exits.
1800 processor.max_cstate= [HW,ACPI]
1801 Limit processor to maximum C-state
1802 max_cstate=9 overrides any DMI blacklist limit.
1804 processor.nocst [HW,ACPI]
1805 Ignore the _CST method to determine C-states,
1806 instead using the legacy FADT method
1808 prompt_ramdisk= [RAM] List of RAM disks to prompt for floppy disk
1810 See Documentation/ramdisk.txt.
1812 psmouse.proto= [HW,MOUSE] Highest PS2 mouse protocol extension to
1813 probe for; one of (bare|imps|exps|lifebook|any).
1814 psmouse.rate= [HW,MOUSE] Set desired mouse report rate, in reports
1816 psmouse.resetafter= [HW,MOUSE]
1817 Try to reset the device after so many bad packets
1820 [HW,MOUSE] Set desired mouse resolution, in dpi.
1821 psmouse.smartscroll=
1822 [HW,MOUSE] Controls Logitech smartscroll autorepeat.
1823 0 = disabled, 1 = enabled (default).
1825 pss= [HW,OSS] Personal Sound System (ECHO ESC614)
1827 <io>,<mss_io>,<mss_irq>,<mss_dma>,<mpu_io>,<mpu_irq>
1830 See Documentation/paride.txt.
1833 [KNL] Number of legacy pty's. Overwrites compiled-in
1836 quiet [KNL] Disable most log messages
1841 See Documentation/md.txt.
1843 ramdisk_blocksize= [RAM]
1844 See Documentation/ramdisk.txt.
1846 ramdisk_size= [RAM] Sizes of RAM disks in kilobytes
1847 See Documentation/ramdisk.txt.
1849 rcupdate.blimit= [KNL,BOOT]
1850 Set maximum number of finished RCU callbacks to process
1853 rcupdate.qhimark= [KNL,BOOT]
1854 Set threshold of queued
1855 RCU callbacks over which batch limiting is disabled.
1857 rcupdate.qlowmark= [KNL,BOOT]
1858 Set threshold of queued RCU callbacks below which
1859 batch limiting is re-enabled.
1863 Run specified binary instead of /init from the ramdisk,
1864 used for early userspace startup. See initrd.
1866 reboot= [BUGS=X86-32,BUGS=ARM,BUGS=IA-64] Rebooting mode
1867 Format: <reboot_mode>[,<reboot_mode2>[,...]]
1868 See arch/*/kernel/reboot.c or arch/*/kernel/process.c
1871 [KNL, SMP] Set scheduler's default relax_domain_level.
1872 See Documentation/cpusets.txt.
1874 reserve= [KNL,BUGS] Force the kernel to ignore some iomem area
1876 reservetop= [X86-32]
1878 Reserves a hole at the top of the kernel virtual
1881 reset_devices [KNL] Force drivers to reset the underlying device
1882 during initialization.
1885 Specify the partition device for software suspend
1887 resume_offset= [SWSUSP]
1888 Specify the offset from the beginning of the partition
1889 given by "resume=" at which the swap header is located,
1890 in <PAGE_SIZE> units (needed only for swap files).
1891 See Documentation/power/swsusp-and-swap-files.txt
1893 retain_initrd [RAM] Keep initrd memory after extraction
1895 rhash_entries= [KNL,NET]
1896 Set number of hash buckets for route cache
1898 riscom8= [HW,SERIAL]
1899 Format: <io_board1>[,<io_board2>[,...<io_boardN>]]
1901 ro [KNL] Mount root device read-only on boot
1903 root= [KNL] Root filesystem
1905 rootdelay= [KNL] Delay (in seconds) to pause before attempting to
1906 mount the root filesystem
1908 rootflags= [KNL] Set root filesystem mount option string
1910 rootfstype= [KNL] Set root filesystem type
1912 rootwait [KNL] Wait (indefinitely) for root device to show up.
1913 Useful for devices that are detected asynchronously
1914 (e.g. USB and MMC devices).
1916 root_plug.vendor_id=
1917 [ROOTPLUG] Override the default vendor ID
1919 root_plug.product_id=
1920 [ROOTPLUG] Override the default product ID
1923 [ROOTPLUG] Enable debugging output
1925 rw [KNL] Mount root device read-write on boot
1927 S [KNL] Run init in single mode
1930 See drivers/net/irda/sa1100_ir.c.
1932 sbni= [NET] Granch SBNI12 leased line adapter
1934 sc1200wdt= [HW,WDT] SC1200 WDT (watchdog) driver
1935 Format: <io>[,<timeout>[,<isapnp>]]
1937 scsi_debug_*= [SCSI]
1938 See drivers/scsi/scsi_debug.c.
1940 scsi_default_dev_flags=
1941 [SCSI] SCSI default device flags
1944 scsi_dev_flags= [SCSI] Black/white list entry for vendor and model
1945 Format: <vendor>:<model>:<flags>
1946 (flags are integer value)
1948 scsi_logging_level= [SCSI] a bit mask of logging levels
1949 See drivers/scsi/scsi_logging.h for bits. Also
1950 settable via sysctl at dev.scsi.logging_level
1951 (/proc/sys/dev/scsi/logging_level).
1952 There is also a nice 'scsi_logging_level' script in the
1953 S390-tools package, available for download at
1954 http://www-128.ibm.com/developerworks/linux/linux390/s390-tools-1.5.4.html
1956 scsi_mod.scan= [SCSI] sync (default) scans SCSI busses as they are
1957 discovered. async scans them in kernel threads,
1958 allowing boot to proceed. none ignores them, expecting
1959 user space to do the scan.
1961 selinux [SELINUX] Disable or enable SELinux at boot time.
1962 Format: { "0" | "1" }
1963 See security/selinux/Kconfig help text.
1966 Default value is set via kernel config option.
1967 If enabled at boot time, /selinux/disable can be used
1968 later to disable prior to initial policy load.
1970 selinux_compat_net =
1971 [SELINUX] Set initial selinux_compat_net flag value.
1972 Format: { "0" | "1" }
1973 0 -- use new secmark-based packet controls
1974 1 -- use legacy packet controls
1975 Default value is 0 (preferred).
1976 Value can be changed at runtime via
1977 /selinux/compat_net.
1979 serialnumber [BUGS=X86-32]
1982 Maximal number of shapers.
1984 show_msr= [x86] show boot-time MSR settings
1985 Format: { <integer> }
1986 Show boot-time (BIOS-initialized) MSR settings.
1987 The parameter means the number of CPUs to show,
1988 for example 1 means boot CPU only.
1991 See header of drivers/scsi/sim710.c.
1998 slub_debug[=options[,slabs]] [MM, SLUB]
1999 Enabling slub_debug allows one to determine the
2000 culprit if slab objects become corrupted. Enabling
2001 slub_debug can create guard zones around objects and
2002 may poison objects when not in use. Also tracks the
2003 last alloc / free. For more information see
2004 Documentation/vm/slub.txt.
2006 slub_max_order= [MM, SLUB]
2007 Determines the maximum allowed order for slabs.
2008 A high setting may cause OOMs due to memory
2009 fragmentation. For more information see
2010 Documentation/vm/slub.txt.
2012 slub_min_objects= [MM, SLUB]
2013 The minimum number of objects per slab. SLUB will
2014 increase the slab order up to slub_max_order to
2015 generate a sufficiently large slab able to contain
2016 the number of objects indicated. The higher the number
2017 of objects the smaller the overhead of tracking slabs
2018 and the less frequently locks need to be acquired.
2019 For more information see Documentation/vm/slub.txt.
2021 slub_min_order= [MM, SLUB]
2022 Determines the mininum page order for slabs. Must be
2023 lower than slub_max_order.
2024 For more information see Documentation/vm/slub.txt.
2026 slub_nomerge [MM, SLUB]
2027 Disable merging of slabs with similar size. May be
2028 necessary if there is some reason to distinguish
2029 allocs to different slabs. Debug options disable
2030 merging on their own.
2031 For more information see Documentation/vm/slub.txt.
2034 Format: <io1>[,<io2>[,...,<io8>]]
2036 smp-alt-once [X86-32,SMP] On a hotplug CPU system, only
2037 attempt to substitute SMP alternatives once at boot.
2039 smsc-ircc2.nopnp [HW] Don't use PNP to discover SMC devices
2040 smsc-ircc2.ircc_cfg= [HW] Device configuration I/O port
2041 smsc-ircc2.ircc_sir= [HW] SIR base I/O port
2042 smsc-ircc2.ircc_fir= [HW] FIR base I/O port
2043 smsc-ircc2.ircc_irq= [HW] IRQ line
2044 smsc-ircc2.ircc_dma= [HW] DMA channel
2045 smsc-ircc2.ircc_transceiver= [HW] Transceiver type:
2046 0: Toshiba Satellite 1800 (GP data pin select)
2047 1: Fast pin select (default)
2050 snd-ad1816a= [HW,ALSA]
2052 snd-ad1848= [HW,ALSA]
2054 snd-ali5451= [HW,ALSA]
2056 snd-als100= [HW,ALSA]
2058 snd-als4000= [HW,ALSA]
2060 snd-azt2320= [HW,ALSA]
2062 snd-cmi8330= [HW,ALSA]
2064 snd-cmipci= [HW,ALSA]
2066 snd-cs4231= [HW,ALSA]
2068 snd-cs4232= [HW,ALSA]
2070 snd-cs4236= [HW,ALSA]
2072 snd-cs4281= [HW,ALSA]
2074 snd-cs46xx= [HW,ALSA]
2076 snd-dt019x= [HW,ALSA]
2078 snd-dummy= [HW,ALSA]
2080 snd-emu10k1= [HW,ALSA]
2082 snd-ens1370= [HW,ALSA]
2084 snd-ens1371= [HW,ALSA]
2086 snd-es968= [HW,ALSA]
2088 snd-es1688= [HW,ALSA]
2090 snd-es18xx= [HW,ALSA]
2092 snd-es1938= [HW,ALSA]
2094 snd-es1968= [HW,ALSA]
2096 snd-fm801= [HW,ALSA]
2098 snd-gusclassic= [HW,ALSA]
2100 snd-gusextreme= [HW,ALSA]
2102 snd-gusmax= [HW,ALSA]
2106 snd-ice1712= [HW,ALSA]
2108 snd-intel8x0= [HW,ALSA]
2110 snd-interwave= [HW,ALSA]
2115 snd-korg1212= [HW,ALSA]
2117 snd-maestro3= [HW,ALSA]
2119 snd-mpu401= [HW,ALSA]
2121 snd-mtpav= [HW,ALSA]
2123 snd-nm256= [HW,ALSA]
2125 snd-opl3sa2= [HW,ALSA]
2133 snd-opti93x= [HW,ALSA]
2137 snd-rme32= [HW,ALSA]
2139 snd-rme96= [HW,ALSA]
2141 snd-rme9652= [HW,ALSA]
2147 snd-sbawe= [HW,ALSA]
2149 snd-serial= [HW,ALSA]
2151 snd-sgalaxy= [HW,ALSA]
2153 snd-sonicvibes= [HW,ALSA]
2158 snd-sun-cs4231= [HW,ALSA]
2160 snd-trident= [HW,ALSA]
2162 snd-usb-audio= [HW,ALSA,USB]
2164 snd-via82xx= [HW,ALSA]
2166 snd-virmidi= [HW,ALSA]
2168 snd-wavefront= [HW,ALSA]
2170 snd-ymfpci= [HW,ALSA]
2173 [KNL] Should the soft-lockup detector generate panics.
2175 sonypi.*= [HW] Sony Programmable I/O Control Device driver
2176 See Documentation/sonypi.txt
2178 specialix= [HW,SERIAL] Specialix multi-serial port adapter
2179 See Documentation/specialix.txt.
2181 spia_io_base= [HW,MTD]
2187 Format: <io>,<irq>,<dma>,<mpu_io>,<mpu_irq>
2189 st= [HW,SCSI] SCSI tape parameters (buffers, etc.)
2190 See Documentation/scsi/st.txt.
2194 Set the STI (builtin display/keyboard on the HP-PARISC
2195 machines) console (graphic card) which should be used
2196 as the initial boot-console.
2197 See also comment in drivers/video/console/sticore.c.
2200 See comment in drivers/video/console/sticore.c.
2203 Format: bpp:<bpp1>[:<bpp2>[:<bpp3>...]]
2207 Control how the NFS server code allocates CPUs to
2208 service thread pools. Depending on how many NICs
2209 you have and where their interrupts are bound, this
2210 option will affect which CPUs will do NFS serving.
2211 Note: this parameter cannot be changed while the
2212 NFS server is running.
2214 auto the server chooses an appropriate mode
2215 automatically using heuristics
2216 global a single global pool contains all CPUs
2217 percpu one pool for each CPU
2218 pernode one pool for each NUMA node (equivalent
2219 to global on non-NUMA machines)
2221 swiotlb= [IA-64] Number of I/O TLB slabs
2225 sym53c416= [HW,SCSI]
2226 See header of drivers/scsi/sym53c416.c.
2228 sysrq_always_enabled
2230 Ignore sysrq setting - this boot parameter will
2231 neutralize any effect of /proc/sys/kernel/sysrq.
2232 Useful for debugging.
2235 See header of drivers/scsi/t128.c.
2239 test_suspend= [SUSPEND]
2240 Specify "mem" (for Suspend-to-RAM) or "standby" (for
2241 standby suspend) as the system sleep state to briefly
2242 enter during system startup. The system is woken from
2243 this state using a wakeup-capable RTC alarm.
2245 thash_entries= [KNL,NET]
2246 Set number of hash buckets for TCP connection
2248 thermal.act= [HW,ACPI]
2249 -1: disable all active trip points in all thermal zones
2250 <degrees C>: override all lowest active trip points
2252 thermal.crt= [HW,ACPI]
2253 -1: disable all critical trip points in all thermal zones
2254 <degrees C>: override all critical trip points
2256 thermal.nocrt= [HW,ACPI]
2257 Set to disable actions on ACPI thermal zone
2258 critical and hot trip points.
2260 thermal.off= [HW,ACPI]
2261 1: disable ACPI thermal control
2263 thermal.psv= [HW,ACPI]
2264 -1: disable all passive trip points
2265 <degrees C>: override all passive trip points to this value
2267 thermal.tzp= [HW,ACPI]
2268 Specify global default ACPI thermal zone polling rate
2269 <deci-seconds>: poll all this frequency
2270 0: no polling (default)
2273 See comment before function dc390_setup() in
2274 drivers/scsi/tmscsim.c.
2278 trix= [HW,OSS] MediaTrix AudioTrix Pro
2280 <io>,<irq>,<dma>,<dma2>,<sb_io>,<sb_irq>,<sb_dma>,<mpu_io>,<mpu_irq>
2282 turbografx.map[2|3]= [HW,JOY]
2283 TurboGraFX parallel port interface
2285 <port#>,<js1>,<js2>,<js3>,<js4>,<js5>,<js6>,<js7>
2286 See also Documentation/input/joystick-parport.txt
2288 u14-34f= [HW,SCSI] UltraStor 14F/34F SCSI host adapter
2289 See header of drivers/scsi/u14-34f.c.
2298 [USB] Ignore overcurrent events (default N).
2299 Some badly-designed motherboards generate lots of
2300 bogus events, for ports that aren't wired to
2301 anything. Set this parameter to avoid log spamming.
2302 Note that genuine overcurrent events won't be
2307 Set unknown_nmi_panic=1 early on boot.
2309 usbcore.autosuspend=
2310 [USB] The autosuspend time delay (in seconds) used
2311 for newly-detected USB devices (default 2). This
2312 is the time required before an idle device will be
2313 autosuspended. Devices for which the delay is set
2314 to a negative value won't be autosuspended at all.
2316 usbcore.usbfs_snoop=
2317 [USB] Set to log all usbfs traffic (default 0 = off).
2319 usbcore.blinkenlights=
2320 [USB] Set to cycle leds on hubs (default 0 = off).
2322 usbcore.old_scheme_first=
2323 [USB] Start with the old device initialization
2324 scheme (default 0 = off).
2326 usbcore.use_both_schemes=
2327 [USB] Try the other device initialization scheme
2328 if the first one fails (default 1 = enabled).
2330 usbcore.initial_descriptor_timeout=
2331 [USB] Specifies timeout for the initial 64-byte
2332 USB_REQ_GET_DESCRIPTOR request in milliseconds
2333 (default 5000 = 5.0 seconds).
2336 [USBHID] The interval which mice are to be polled at.
2338 add_efi_memmap [EFI; x86-32,X86-64] Include EFI memory map in
2339 kernel's map of available physical RAM.
2341 vdso= [X86-32,SH,x86-64]
2342 vdso=2: enable compat VDSO (default with COMPAT_VDSO)
2343 vdso=1: enable VDSO (default)
2344 vdso=0: disable VDSO mapping
2346 vdso32= [X86-32,X86-64]
2347 vdso32=2: enable compat VDSO (default with COMPAT_VDSO)
2348 vdso32=1: enable 32-bit VDSO (default)
2349 vdso32=0: disable 32-bit VDSO mapping
2352 vector=percpu: enable percpu vector domain
2354 video= [FB] Frame buffer configuration
2355 See Documentation/fb/modedb.txt.
2357 vga= [BOOT,X86-32] Select a particular video mode
2358 See Documentation/x86/i386/boot.txt and
2359 Documentation/svga.txt.
2360 Use vga=ask for menu.
2361 This is actually a boot loader parameter; the value is
2362 passed to the kernel using a special protocol.
2364 vmalloc=nn[KMG] [KNL,BOOT] Forces the vmalloc area to have an exact
2365 size of <nn>. This can be used to increase the
2366 minimum size (128MB on x86). It can also be used to
2367 decrease the size and leave more room for directly
2370 vmhalt= [KNL,S390] Perform z/VM CP command after system halt.
2373 vmpanic= [KNL,S390] Perform z/VM CP command after kernel panic.
2376 vmpoff= [KNL,S390] Perform z/VM CP command after power off.
2379 waveartist= [HW,OSS]
2380 Format: <io>,<irq>,<dma>,<dma2>
2383 See header of drivers/scsi/wd33c93.c.
2386 See header of drivers/scsi/wd7000.c.
2389 See Documentation/watchdog/wdt.txt.
2391 xd= [HW,XT] Original XT pre-IDE (RLL encoded) disks.
2392 xd_geo= See header of drivers/block/xd.c.
2394 xirc2ps_cs= [NET,PCMCIA]
2396 <irq>,<irq_mask>,<io>,<full_duplex>,<do_sound>,<lockup_hack>[,<irq2>[,<irq3>[,<irq4>]]]
2398 norandmaps Don't use address space randomization
2399 Equivalent to echo 0 > /proc/sys/kernel/randomize_va_space
2401 ______________________________________________________________________
2405 Add documentation for ALSA options.
2406 Add more DRM drivers.
git://ftp.safe.ca / safe / jmp / linux-2.6 / blob