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 fullflush - enable flushing of IO/TLB entries when
288 they are unmapped. Otherwise they are
289 flushed before they will be reused, which
292 amd_iommu_size= [HW,X86-64]
293 Define the size of the aperture for the AMD IOMMU
294 driver. Possible values are:
295 '32M', '64M' (default), '128M', '256M', '512M', '1G'
297 amijoy.map= [HW,JOY] Amiga joystick support
298 Map of devices attached to JOY0DAT and JOY1DAT
300 See also Documentation/kernel/input/joystick.txt
302 analog.map= [HW,JOY] Analog joystick and gamepad support
303 Specifies type or capabilities of an analog joystick
304 connected to one of 16 gameports
305 Format: <type1>,<type2>,..<type16>
308 Power management functions (SPARCstation-4/5 + deriv.)
310 Disable APC CPU standby support. SPARCstation-Fox does
311 not play well with APC CPU idle - disable it if you have
312 APC and your system crashes randomly.
314 apic= [APIC,i386] Advanced Programmable Interrupt Controller
315 Change the output verbosity whilst booting
316 Format: { quiet (default) | verbose | debug }
317 Change the amount of debugging information output
318 when initialising the APIC and IO-APIC components.
320 apm= [APM] Advanced Power Management
321 See header of arch/x86/kernel/apm_32.c.
323 arcrimi= [HW,NET] ARCnet - "RIM I" (entirely mem-mapped) cards
324 Format: <io>,<irq>,<nodeID>
328 atarimouse= [HW,MOUSE] Atari Mouse
330 atascsi= [HW,SCSI] Atari SCSI
332 atkbd.extra= [HW] Enable extra LEDs and keys on IBM RapidAccess,
333 EzKey and similar keyboards
335 atkbd.reset= [HW] Reset keyboard during initialization
337 atkbd.set= [HW] Select keyboard code set
338 Format: <int> (2 = AT (default), 3 = PS/2)
340 atkbd.scroll= [HW] Enable scroll wheel on MS Office and similar
343 atkbd.softraw= [HW] Choose between synthetic and real raw mode
344 Format: <bool> (0 = real, 1 = synthetic (default))
346 atkbd.softrepeat= [HW]
347 Use software keyboard repeat
351 baycom_epp= [HW,AX25]
354 baycom_par= [HW,AX25] BayCom Parallel Port AX.25 Modem
356 See header of drivers/net/hamradio/baycom_par.c.
358 baycom_ser_fdx= [HW,AX25]
359 BayCom Serial Port AX.25 Modem (Full Duplex Mode)
360 Format: <io>,<irq>,<mode>[,<baud>]
361 See header of drivers/net/hamradio/baycom_ser_fdx.c.
363 baycom_ser_hdx= [HW,AX25]
364 BayCom Serial Port AX.25 Modem (Half Duplex Mode)
365 Format: <io>,<irq>,<mode>
366 See header of drivers/net/hamradio/baycom_ser_hdx.c.
368 boot_delay= Milliseconds to delay each printk during boot.
369 Values larger than 10 seconds (10000) are changed to
373 bootmem_debug [KNL] Enable bootmem allocator debug messages.
375 bttv.card= [HW,V4L] bttv (bt848 + bt878 based grabber cards)
376 bttv.radio= Most important insmod options are available as
378 bttv.pll= See Documentation/video4linux/bttv/Insmod-options
379 bttv.tuner= and Documentation/video4linux/bttv/CARDLIST
382 See drivers/scsi/BusLogic.c, comment before function
383 BusLogic_ParseDriverOptions().
385 c101= [NET] Moxa C101 synchronous serial card
387 cachesize= [BUGS=X86-32] Override level 2 CPU cache size detection.
388 Sometimes CPU hardware bugs make them report the cache
389 size incorrectly. The kernel will attempt work arounds
390 to fix known problems, but for some CPUs it is not
391 possible to determine what the correct size should be.
392 This option provides an override for these situations.
394 security= [SECURITY] Choose a security module to enable at boot.
395 If this boot parameter is not specified, only the first
396 security module asking for security registration will be
397 loaded. An invalid security module name will be treated
398 as if no module has been chosen.
401 [SECURITY] Disable capabilities. This would normally
402 be used only if an alternative security model is to be
403 configured. Potentially dangerous and should only be
404 used if you are entirely sure of the consequences.
406 ccw_timeout_log [S390]
407 See Documentation/s390/CommonIO for details.
409 cgroup_disable= [KNL] Disable a particular controller
410 Format: {name of the controller(s) to disable}
411 {Currently supported controllers - "memory"}
413 checkreqprot [SELINUX] Set initial checkreqprot flag value.
414 Format: { "0" | "1" }
415 See security/selinux/Kconfig help text.
416 0 -- check protection applied by kernel (includes
417 any implied execute protection).
418 1 -- check protection requested by application.
419 Default value is set via a kernel config option.
420 Value can be changed at runtime via
421 /selinux/checkreqprot.
424 See Documentation/s390/CommonIO for details.
426 clock= [BUGS=X86-32, HW] gettimeofday clocksource override.
428 Forces specified clocksource (if available) to be used
429 when calculating gettimeofday(). If specified
430 clocksource is not available, it defaults to PIT.
431 Format: { pit | tsc | cyclone | pmtmr }
433 clocksource= [GENERIC_TIME] Override the default clocksource
435 Override the default clocksource and use the clocksource
436 with the name specified.
437 Some clocksource names to choose from, depending on
439 [all] jiffies (this is the base, fallback clocksource)
441 [ARM] imx_timer1,OSTS,netx_timer,mpu_timer2,
442 pxa_timer,timer3,32k_counter,timer0_1
444 [X86-32] pit,hpet,tsc,vmi-timer;
445 scx200_hrt on Geode; cyclone on IBM x440
453 clearcpuid=BITNUM [X86]
454 Disable CPUID feature X for the kernel. See
455 include/asm-x86/cpufeature.h for the valid bit numbers.
456 Note the Linux specific bits are not necessarily
457 stable over kernel options, but the vendor specific
459 Also note that user programs calling CPUID directly
460 or using the feature without checking anything
461 will still see it. This just prevents it from
462 being used by the kernel or shown in /proc/cpuinfo.
463 Also note the kernel might malfunction if you disable
466 code_bytes [IA32/X86_64] How many bytes of object code to print
471 hpet= [X86-32,HPET] option to control HPET usage
472 Format: { enable (default) | disable | force }
473 disable: disable HPET and use PIT instead
474 force: allow force enabled of undocumented chips (ICH4,
477 com20020= [HW,NET] ARCnet - COM20020 chipset
479 <io>[,<irq>[,<nodeID>[,<backplane>[,<ckp>[,<timeout>]]]]]
481 com90io= [HW,NET] ARCnet - COM90xx chipset (IO-mapped buffers)
485 ARCnet - COM90xx chipset (memory-mapped buffers)
486 Format: <io>[,<irq>[,<memstart>]]
488 condev= [HW,S390] console device
491 console= [KNL] Output console device and options.
493 tty<n> Use the virtual console device <n>.
497 Use the specified serial port. The options are of
498 the form "bbbbpnf", where "bbbb" is the baud rate,
499 "p" is parity ("n", "o", or "e"), "n" is number of
500 bits, and "f" is flow control ("r" for RTS or
501 omit it). Default is "9600n8".
503 See Documentation/serial-console.txt for more
505 Documentation/networking/netconsole.txt for an
508 uart[8250],io,<addr>[,options]
509 uart[8250],mmio,<addr>[,options]
510 Start an early, polled-mode console on the 8250/16550
511 UART at the specified I/O port or MMIO address,
512 switching to the matching ttyS device later. The
513 options are the same as for ttyS, above.
515 If the device connected to the port is not a TTY but a braille
516 device, prepend "brl," before the device type, for instance
518 For now, only VisioBraille is supported.
520 earlycon= [KNL] Output early console device and options.
521 uart[8250],io,<addr>[,options]
522 uart[8250],mmio,<addr>[,options]
523 Start an early, polled-mode console on the 8250/16550
524 UART at the specified I/O port or MMIO address.
525 The options are the same as for ttyS, above.
528 [HW] Never suspend the console
529 Disable suspending of consoles during suspend and
530 hibernate operations. Once disabled, debugging
531 messages can reach various consoles while the rest
532 of the system is being put to sleep (ie, while
533 debugging driver suspend/resume hooks). This may
534 not work reliably with all consoles, but is known
535 to work with serial and VGA consoles.
537 cpcihp_generic= [HW,PCI] Generic port I/O CompactPCI driver
539 <first_slot>,<last_slot>,<port>,<enum_bit>[,<debug>]
541 crashkernel=nn[KMG]@ss[KMG]
542 [KNL] Reserve a chunk of physical memory to
543 hold a kernel to switch to with kexec on panic.
545 crashkernel=range1:size1[,range2:size2,...][@offset]
546 [KNL] Same as above, but depends on the memory
547 in the running system. The syntax of range is
548 start-[end] where start and end are both
549 a memory unit (amount[KMG]). See also
550 Documentation/kdump/kdump.txt for a example.
553 Format: <io>,<irq>,<dma>,<dma2>,<mpuio>,<mpuirq>
558 cs89x0_media= [HW,NET]
559 Format: { rj45 | aui | bnc }
562 See header of drivers/s390/block/dasd_devmap.c.
564 db9.dev[2|3]= [HW,JOY] Multisystem joystick support via parallel port
565 (one device per port)
566 Format: <port#>,<type>
567 See also Documentation/input/joystick-parport.txt
569 debug [KNL] Enable kernel debugging (events log level).
572 [KNL] verbose self-tests
574 Print debugging info while doing the locking API
576 We default to 0 (no extra messages), setting it to
577 1 will print _a lot_ more information - normally
578 only useful to kernel developers.
580 debug_objects [KNL] Enable object debugging
582 debugpat [X86] Enable PAT debugging
584 decnet.addr= [HW,NET]
585 Format: <area>[,<node>]
586 See also Documentation/networking/decnet.txt.
589 Format: <blue0>,<blue1>,<blue2>,...,<blue15>
590 Change the default blue palette of the console.
591 This is a 16-member array composed of values
595 Format: <green0>,<green1>,<green2>,...,<green15>
596 Change the default green palette of the console.
597 This is a 16-member array composed of values
601 Format: <red0>,<red1>,<red2>,...,<red15>
602 Change the default red palette of the console.
603 This is a 16-member array composed of values
609 Set system-wide default UTF-8 mode for all tty's.
610 Default is 1, i.e. UTF-8 mode is enabled for all
611 newly opened terminals.
614 Set number of hash buckets for dentry cache.
617 IO parameters + enable/disable command.
619 digiepca= [HW,SERIAL]
620 See drivers/char/README.epca and
621 Documentation/digiepca.txt.
623 disable_mtrr_cleanup [X86]
624 enable_mtrr_cleanup [X86]
625 The kernel tries to adjust MTRR layout from continuous
626 to discrete, to make X server driver able to add WB
627 entry later. This parameter enables/disables that.
629 mtrr_chunk_size=nn[KMG] [X86]
630 used for mtrr cleanup. It is largest continous chunk
631 that could hold holes aka. UC entries.
633 mtrr_gran_size=nn[KMG] [X86]
634 Used for mtrr cleanup. It is granularity of mtrr block.
636 Large value could prevent small alignment from
639 mtrr_spare_reg_nr=n [X86]
641 Range: 0,7 : spare reg number
643 Used for mtrr cleanup. It is spare mtrr entries number.
644 Set to 2 or more if your graphical card needs more.
646 disable_mtrr_trim [X86, Intel and AMD only]
647 By default the kernel will trim any uncacheable
648 memory out of your available memory pool based on
649 MTRR settings. This parameter disables that behavior,
650 possibly causing your machine to run very slowly.
652 dmasound= [HW,OSS] Sound subsystem buffers
658 earlyprintk= [X86-32,X86-64,SH,BLACKFIN]
660 earlyprintk=serial[,ttySn[,baudrate]]
663 Append ",keep" to not disable it when the real console
666 Only vga or serial or usb debug port at a time.
668 Currently only ttyS0 and ttyS1 are supported.
670 Interaction with the standard serial driver is not
673 The VGA output is eventually overwritten by the real
679 Format: {"off" | "on" | "skip[mbr]"}
681 eisa_irq_edge= [PARISC,HW]
682 See header of drivers/parisc/eisa.c.
685 See comment before function elanfreq_setup() in
686 arch/x86/kernel/cpu/cpufreq/elanfreq.c.
689 Format: {"anticipatory" | "cfq" | "deadline" | "noop"}
690 See Documentation/block/as-iosched.txt and
691 Documentation/block/deadline-iosched.txt for details.
693 elfcorehdr= [X86-32, X86_64]
694 Specifies physical address of start of kernel core
695 image elf header. Generally kexec loader will
696 pass this option to capture kernel.
697 See Documentation/kdump/kdump.txt for details.
699 enforcing [SELINUX] Set initial enforcing status.
701 See security/selinux/Kconfig help text.
702 0 -- permissive (log only, no denials).
703 1 -- enforcing (deny and log).
705 Value can be changed at runtime via /selinux/enforce.
708 Format: <spdif>,[<nomix>,[<amplifier>]]
709 See also header of sound/oss/es1371.c.
711 ether= [HW,NET] Ethernet cards parameters
712 This option is obsoleted by the "netdev=" option, which
713 has equivalent usage. See its documentation for details.
715 eurwdt= [HW,WDT] Eurotech CPU-1220/1410 onboard watchdog.
720 fail_make_request=[KNL]
721 General fault injection mechanism.
722 Format: <interval>,<probability>,<space>,<times>
723 See also /Documentation/fault-injection/.
726 See header of drivers/scsi/fd_mcs.c.
729 See header of drivers/scsi/fdomain.c.
732 See Documentation/floppy.txt.
734 force_pal_cache_flush
735 [IA-64] Avoid check_sal_cache_flush which may hang on
736 buggy SAL_CACHE_FLUSH implementations. Using this
737 parameter will force ia64_sal_cache_flush to call
738 ia64_pal_cache_flush instead of SAL_CACHE_FLUSH.
741 [HW,JOY] Multisystem joystick and NES/SNES/PSX pad
742 support via parallel port (up to 5 devices per port)
743 Format: <port#>,<pad1>,<pad2>,<pad3>,<pad4>,<pad5>
744 See also Documentation/input/joystick-parport.txt
748 gart_fix_e820= [X86_64] disable the fix e820 for K8 GART
753 See header of drivers/scsi/gdth.c.
755 gpt [EFI] Forces disk with valid GPT signature but
756 invalid Protective MBR to be treated as GPT.
760 hashdist= [KNL,NUMA] Large hashes allocated during boot
761 are distributed across NUMA nodes. Defaults on
762 for IA-64, off otherwise.
763 Format: 0 | 1 (for off | on)
765 hcl= [IA-64] SGI's Hardware Graph compatibility layer
767 hd= [EIDE] (E)IDE hard drive subsystem geometry
768 Format: <cyl>,<head>,<sect>
770 highmem=nn[KMG] [KNL,BOOT] forces the highmem zone to have an exact
771 size of <nn>. This works even on boxes that have no
772 highmem otherwise. This also works to reduce highmem
773 size on bigger boxes.
775 highres= [KNL] Enable/disable high resolution timer mode.
776 Valid parameters: "on", "off"
780 See Documentation/isdn/README.HiSax.
782 hugepages= [HW,X86-32,IA-64] HugeTLB pages to allocate at boot.
783 hugepagesz= [HW,IA-64,PPC,X86-64] The size of the HugeTLB pages.
784 On x86-64 and powerpc, this option can be specified
785 multiple times interleaved with hugepages= to reserve
786 huge pages of different sizes. Valid pages sizes on
787 x86-64 are 2M (when the CPU supports "pse") and 1G
788 (when the CPU supports the "pdpe1gb" cpuinfo flag)
789 Note that 1GB pages can only be allocated at boot time
790 using hugepages= and not freed afterwards.
792 [same as hugepagesz=] The size of the default
793 HugeTLB page size. This is the size represented by
794 the legacy /proc/ hugepages APIs, used for SHM, and
795 default size when mounting hugetlbfs filesystems.
796 Defaults to the default architecture's huge page size
799 i8042.debug [HW] Toggle i8042 debug mode
800 i8042.direct [HW] Put keyboard port into non-translated mode
801 i8042.dumbkbd [HW] Pretend that controller can only read data from
802 keyboard and cannot control its state
803 (Don't attempt to blink the leds)
804 i8042.noaux [HW] Don't check for auxiliary (== mouse) port
805 i8042.nokbd [HW] Don't check/create keyboard port
806 i8042.noloop [HW] Disable the AUX Loopback command while probing
808 i8042.nomux [HW] Don't check presence of an active multiplexing
810 i8042.nopnp [HW] Don't use ACPIPnP / PnPBIOS to discover KBD/AUX
813 [HW] Frequency with which keyboard LEDs should blink
814 when kernel panics (default is 0.5 sec)
815 i8042.reset [HW] Reset the controller during init and cleanup
816 i8042.unlock [HW] Unlock (ignore) the keylock
820 i8k.ignore_dmi [HW] Continue probing hardware even if DMI data
821 indicates that the driver is running on unsupported
823 i8k.force [HW] Activate i8k driver even if SMM BIOS signature
824 does not match list of supported models.
826 [HW] Report power status in /proc/i8k
827 (disabled by default)
828 i8k.restricted [HW] Allow controlling fans only if SYS_ADMIN
831 ibmmcascsi= [HW,MCA,SCSI] IBM MicroChannel SCSI adapter
832 See Documentation/mca.txt.
835 Format: <io>[,<membase>[,<icn_id>[,<icn_id2>]]]
837 ide= [HW] (E)IDE subsystem
838 Format: ide=nodma or ide=doubler
839 See Documentation/ide/ide.txt.
841 idebus= [HW] (E)IDE subsystem - VLB/PCI bus speed
842 See Documentation/ide/ide.txt.
845 Format: idle=poll or idle=mwait, idle=halt, idle=nomwait
846 Poll forces a polling idle loop that can slightly improves the performance
847 of waking up a idle CPU, but will use a lot of power and make the system
848 run hot. Not recommended.
849 idle=mwait. On systems which support MONITOR/MWAIT but the kernel chose
850 to not use it because it doesn't save as much power as a normal idle
851 loop use the MONITOR/MWAIT idle loop anyways. Performance should be the same
853 idle=halt. Halt is forced to be used for CPU idle.
854 In such case C2/C3 won't be used again.
855 idle=nomwait. Disable mwait for CPU C-states
857 ide-pci-generic.all-generic-ide [HW] (E)IDE subsystem
858 Claim all unknown PCI IDE storage controllers.
860 ignore_loglevel [KNL]
861 Ignore loglevel setting - this will print /all/
862 kernel messages to the console. Useful for debugging.
865 Set number of hash buckets for inode cache.
868 See header of drivers/scsi/in2000.c.
872 Run specified binary instead of /sbin/init as init
875 initcall_debug [KNL] Trace initcalls as they are executed. Useful
876 for working out where the kernel is dying during
879 initrd= [BOOT] Specify the location of the initial ramdisk
881 inport.irq= [HW] Inport (ATI XL and Microsoft) busmouse driver
899 intel_iommu= [DMAR] Intel IOMMU driver (DMAR) option
901 Disable intel iommu driver.
902 igfx_off [Default Off]
903 By default, gfx is mapped as normal device. If a gfx
904 device has a dedicated DMAR unit, the DMAR unit is
905 bypassed by not enabling DMAR with this option. In
906 this case, gfx device will use physical address for
909 With this option iommu will not optimize to look
910 for io virtual address below 32 bit forcing dual
911 address cycle on pci bus for cards supporting greater
912 than 32 bit addressing. The default is to look
913 for translation below 32 bit and if not available
914 then look in the higher range.
916 With this option on every unmap_single operation will
917 result in a hardware IOTLB flush operation as opposed
918 to batching them for performance.
920 io_delay= [X86-32,X86-64] I/O delay method
922 Standard port 0x80 based delay
924 Alternate port 0xed based delay (needed on some systems)
926 Simple two microseconds delay
930 io7= [HW] IO7 for Marvel based alpha systems
931 See comment before marvel_specify_io7 in
932 arch/alpha/kernel/core_marvel.c.
935 See Documentation/filesystems/nfsroot.txt.
937 ip2= [HW] Set IO/IRQ pairs for up to 4 IntelliPort boards
938 See comment before ip2_setup() in
939 drivers/char/ip2/ip2base.c.
941 ips= [HW,SCSI] Adaptec / IBM ServeRAID controller
942 See header of drivers/scsi/ips.c.
944 ports= [IP_VS_FTP] IPVS ftp helper module
946 Up to 8 (IP_VS_APP_MAX_PORTS) ports
948 Format: <port>,<port>....
951 When an interrupt is not handled search all handlers
952 for it. Intended to get systems with badly broken
956 When an interrupt is not handled search all handlers
957 for it. Also check all handlers each timer
958 interrupt. Intended to get systems with badly broken
962 Format: <RDP>,<reset>,<pci_scan>,<verbosity>
964 isolcpus= [KNL,SMP] Isolate CPUs from the general scheduler.
966 <cpu number>,...,<cpu number>
968 <cpu number>-<cpu number> (must be a positive range in ascending order)
970 <cpu number>,...,<cpu number>-<cpu number>
971 This option can be used to specify one or more CPUs
972 to isolate from the general SMP balancing and scheduling
973 algorithms. The only way to move a process onto or off
974 an "isolated" CPU is via the CPU affinity syscalls.
975 <cpu number> begins at 0 and the maximum value is
976 "number of CPUs in system - 1".
978 This option is the preferred way to isolate CPUs. The
979 alternative -- manually setting the CPU mask of all
980 tasks in the system -- can cause problems and
981 suboptimal load balancer performance.
985 js= [HW,JOY] Analog joystick
986 See Documentation/input/joystick.txt.
988 kernelcore=nn[KMG] [KNL,X86-32,IA-64,PPC,X86-64] This parameter
989 specifies the amount of memory usable by the kernel
990 for non-movable allocations. The requested amount is
991 spread evenly throughout all nodes in the system. The
992 remaining memory in each node is used for Movable
993 pages. In the event, a node is too small to have both
994 kernelcore and Movable pages, kernelcore pages will
995 take priority and other nodes will have a larger number
996 of kernelcore pages. The Movable zone is used for the
997 allocation of pages that may be reclaimed or moved
998 by the page migration subsystem. This means that
999 HugeTLB pages may not be allocated from this zone.
1000 Note that allocations like PTEs-from-HighMem still
1001 use the HighMem zone if it exists, and the Normal
1002 zone if it does not.
1004 movablecore=nn[KMG] [KNL,X86-32,IA-64,PPC,X86-64] This parameter
1005 is similar to kernelcore except it specifies the
1006 amount of memory used for migratable allocations.
1007 If both kernelcore and movablecore is specified,
1008 then kernelcore will be at *least* the specified
1009 value but may be more. If movablecore on its own
1010 is specified, the administrator must be careful
1011 that the amount of memory usable for all allocations
1016 kstack=N [X86-32,X86-64] Print N words from the kernel stack
1019 kgdboc= [HW] kgdb over consoles.
1020 Requires a tty driver that supports console polling.
1021 (only serial suported for now)
1022 Format: <serial_device>[,baud]
1024 kmac= [MIPS] korina ethernet MAC address.
1025 Configure the RouterBoard 532 series on-chip
1026 Ethernet adapter MAC address.
1032 lapic [X86-32,APIC] Enable the local APIC even if BIOS
1035 lapic_timer_c2_ok [X86-32,x86-64,APIC] trust the local apic timer in
1038 libata.dma= [LIBATA] DMA control
1039 libata.dma=0 Disable all PATA and SATA DMA
1040 libata.dma=1 PATA and SATA Disk DMA only
1041 libata.dma=2 ATAPI (CDROM) DMA only
1042 libata.dma=4 Compact Flash DMA only
1043 Combinations also work, so libata.dma=3 enables DMA
1044 for disks and CDROMs, but not CFs.
1046 libata.noacpi [LIBATA] Disables use of ACPI in libata suspend/resume
1050 libata.force= [LIBATA] Force configurations. The format is comma
1051 separated list of "[ID:]VAL" where ID is
1052 PORT[:DEVICE]. PORT and DEVICE are decimal numbers
1053 matching port, link or device. Basically, it matches
1054 the ATA ID string printed on console by libata. If
1055 the whole ID part is omitted, the last PORT and DEVICE
1056 values are used. If ID hasn't been specified yet, the
1057 configuration applies to all ports, links and devices.
1059 If only DEVICE is omitted, the parameter applies to
1060 the port and all links and devices behind it. DEVICE
1061 number of 0 either selects the first device or the
1062 first fan-out link behind PMP device. It does not
1063 select the host link. DEVICE number of 15 selects the
1064 host link and device attached to it.
1066 The VAL specifies the configuration to force. As long
1067 as there's no ambiguity shortcut notation is allowed.
1068 For example, both 1.5 and 1.5G would work for 1.5Gbps.
1069 The following configurations can be forced.
1071 * Cable type: 40c, 80c, short40c, unk, ign or sata.
1072 Any ID with matching PORT is used.
1074 * SATA link speed limit: 1.5Gbps or 3.0Gbps.
1076 * Transfer mode: pio[0-7], mwdma[0-4] and udma[0-7].
1077 udma[/][16,25,33,44,66,100,133] notation is also
1080 * [no]ncq: Turn on or off NCQ.
1082 * nohrst, nosrst, norst: suppress hard, soft
1085 If there are multiple matching configurations changing
1086 the same attribute, the last one is used.
1088 load_ramdisk= [RAM] List of ramdisks to load from floppy
1089 See Documentation/ramdisk.txt.
1091 lockd.nlm_grace_period=P [NFS] Assign grace period.
1094 lockd.nlm_tcpport=N [NFS] Assign TCP port.
1097 lockd.nlm_timeout=T [NFS] Assign timeout value.
1100 lockd.nlm_udpport=M [NFS] Assign UDP port.
1103 logibm.irq= [HW,MOUSE] Logitech Bus Mouse Driver
1106 loglevel= All Kernel Messages with a loglevel smaller than the
1107 console loglevel will be printed to the console. It can
1108 also be changed with klogd or other programs. The
1109 loglevels are defined as follows:
1111 0 (KERN_EMERG) system is unusable
1112 1 (KERN_ALERT) action must be taken immediately
1113 2 (KERN_CRIT) critical conditions
1114 3 (KERN_ERR) error conditions
1115 4 (KERN_WARNING) warning conditions
1116 5 (KERN_NOTICE) normal but significant condition
1117 6 (KERN_INFO) informational
1118 7 (KERN_DEBUG) debug-level messages
1120 log_buf_len=n Sets the size of the printk ring buffer, in bytes.
1121 Format: { n | nk | nM }
1122 n must be a power of two. The default size
1123 is set in the kernel config file.
1125 logo.nologo [FB] Disables display of the built-in Linux logo.
1126 This may be used to provide more screen space for
1127 kernel log messages and is useful when debugging
1128 kernel boot problems.
1130 lp=0 [LP] Specify parallel ports to use, e.g,
1131 lp=port[,port...] lp=none,parport0 (lp0 not configured, lp1 uses
1132 lp=reset first parallel port). 'lp=0' disables the
1133 lp=auto printer driver. 'lp=reset' (which can be
1134 specified in addition to the ports) causes
1135 attached printers to be reset. Using
1136 lp=port1,port2,... specifies the parallel ports
1137 to associate lp devices with, starting with
1138 lp0. A port specification may be 'none' to skip
1139 that lp device, or a parport name such as
1140 'parport0'. Specifying 'lp=auto' instead of a
1141 port specification list means that device IDs
1142 from each port should be examined, to see if
1143 an IEEE 1284-compliant printer is attached; if
1144 so, the driver will manage that printer.
1145 See also header of drivers/char/lp.c.
1148 Sets loops_per_jiffy to given constant, thus avoiding
1149 time-consuming boot-time autodetection (up to 250 ms per
1150 CPU). 0 enables autodetection (default). To determine
1151 the correct value for your kernel, boot with normal
1152 autodetection and see what value is printed. Note that
1153 on SMP systems the preset will be applied to all CPUs,
1154 which is likely to cause problems if your CPUs need
1155 significantly divergent settings. An incorrect value
1156 will cause delays in the kernel to be wrong, leading to
1157 unpredictable I/O errors and other breakage. Although
1158 unlikely, in the extreme case this might damage your
1162 Format: <io>,<irq>,<dma>
1164 mac5380= [HW,SCSI] Format:
1165 <can_queue>,<cmd_per_lun>,<sg_tablesize>,<hostid>,<use_tags>
1167 machvec= [IA64] Force the use of a particular machine-vector
1168 (machvec) in a generic kernel.
1169 Example: machvec=hpzx1_swiotlb
1171 max_loop= [LOOP] Maximum number of loopback devices that can
1175 maxcpus= [SMP] Maximum number of processors that an SMP kernel
1176 should make use of. maxcpus=n : n >= 0 limits the
1177 kernel to using 'n' processors. n=0 is a special case,
1178 it is equivalent to "nosmp", which also disables
1181 max_addr=[KMG] [KNL,BOOT,ia64] All physical memory greater than or
1182 equal to this physical address is ignored.
1184 max_luns= [SCSI] Maximum number of LUNs to probe.
1185 Should be between 1 and 2^32-1.
1188 [SCSI] Maximum number of LUNs received.
1189 Should be between 1 and 16384.
1193 mce [X86-32] Machine Check Exception
1195 mce=option [X86-64] See Documentation/x86_64/boot-options.txt
1197 md= [HW] RAID subsystems devices and level
1198 See Documentation/md.txt.
1201 Format: <first>,<last>
1202 Specifies range of consoles to be captured by the MDA.
1204 mem=nn[KMG] [KNL,BOOT] Force usage of a specific amount of memory
1205 Amount of memory to be used when the kernel is not able
1206 to see the whole system memory or for test.
1207 [X86-32] Use together with memmap= to avoid physical
1208 address space collisions. Without memmap= PCI devices
1209 could be placed at addresses belonging to unused RAM.
1211 mem=nopentium [BUGS=X86-32] Disable usage of 4MB pages for kernel
1214 memmap=exactmap [KNL,X86-32,X86_64] Enable setting of an exact
1215 E820 memory map, as specified by the user.
1216 Such memmap=exactmap lines can be constructed based on
1217 BIOS output or other requirements. See the memmap=nn@ss
1220 memmap=nn[KMG]@ss[KMG]
1221 [KNL] Force usage of a specific region of memory
1222 Region of memory to be used, from ss to ss+nn.
1224 memmap=nn[KMG]#ss[KMG]
1225 [KNL,ACPI] Mark specific memory as ACPI data.
1226 Region of memory to be used, from ss to ss+nn.
1228 memmap=nn[KMG]$ss[KMG]
1229 [KNL,ACPI] Mark specific memory as reserved.
1230 Region of memory to be used, from ss to ss+nn.
1231 Example: Exclude memory from 0x18690000-0x1869ffff
1232 memmap=64K$0x18690000
1234 memmap=0x10000$0x18690000
1236 memory_corruption_check=0/1 [X86]
1237 Some BIOSes seem to corrupt the first 64k of
1238 memory when doing things like suspend/resume.
1239 Setting this option will scan the memory
1240 looking for corruption. Enabling this will
1241 both detect corruption and prevent the kernel
1242 from using the memory being corrupted.
1243 However, its intended as a diagnostic tool; if
1244 repeatable BIOS-originated corruption always
1245 affects the same memory, you can use memmap=
1246 to prevent the kernel from using that memory.
1248 memory_corruption_check_size=size [X86]
1249 By default it checks for corruption in the low
1250 64k, making this memory unavailable for normal
1251 use. Use this parameter to scan for
1252 corruption in more or less memory.
1254 memory_corruption_check_period=seconds [X86]
1255 By default it checks for corruption every 60
1256 seconds. Use this parameter to check at some
1257 other rate. 0 disables periodic checking.
1259 memtest= [KNL,X86] Enable memtest
1261 range: 0,4 : pattern number
1262 default : 0 <disable>
1264 meye.*= [HW] Set MotionEye Camera parameters
1265 See Documentation/video4linux/meye.txt.
1267 mfgpt_irq= [IA-32] Specify the IRQ to use for the
1268 Multi-Function General Purpose Timers on AMD Geode
1271 mfgptfix [X86-32] Fix MFGPT timers on AMD Geode platforms when
1272 the BIOS has incorrectly applied a workaround. TinyBIOS
1273 version 0.98 is known to be affected, 0.99 fixes the
1274 problem by letting the user disable the workaround.
1279 [KNL] When CONFIG_DEBUG_MEMORY_INIT is set, this
1280 parameter allows control of the logging verbosity for
1281 the additional memory initialisation checks. A value
1282 of 0 disables mminit logging and a level of 4 will
1283 log everything. Information is printed at KERN_DEBUG
1284 so loglevel=8 may also need to be specified.
1287 [MOUSE] Maximum time between finger touching and
1288 leaving touchpad surface for touch to be considered
1289 a tap and be reported as a left button click (for
1290 touchpads working in absolute mode only).
1292 mousedev.xres= [MOUSE] Horizontal screen resolution, used for devices
1293 reporting absolute coordinates, such as tablets
1294 mousedev.yres= [MOUSE] Vertical screen resolution, used for devices
1295 reporting absolute coordinates, such as tablets
1300 MTD_Partition= [MTD]
1301 Format: <name>,<region-number>,<size>,<offset>
1303 MTD_Region= [MTD] Format:
1304 <name>,<region-number>[,<base>,<size>,<buswidth>,<altbuswidth>]
1307 See drivers/mtd/cmdlinepart.c.
1310 ARM/S3C2412 JIVE boot control
1312 See arch/arm/mach-s3c2412/mach-jive.c
1314 mtouchusb.raw_coordinates=
1315 [HW] Make the MicroTouch USB driver use raw coordinates
1316 ('y', default) or cooked coordinates ('n')
1318 n2= [NET] SDL Inc. RISCom/N2 synchronous serial card
1321 See header of drivers/scsi/NCR_D700.c.
1325 ncr53c400= [HW,SCSI]
1327 ncr53c400a= [HW,SCSI]
1329 ncr53c406a= [HW,SCSI]
1331 ncr53c8xx= [HW,SCSI]
1333 netdev= [NET] Network devices parameters
1334 Format: <irq>,<io>,<mem_start>,<mem_end>,<name>
1335 Note that mem_start is often overloaded to mean
1336 something different and driver-specific.
1337 This usage is only documented in each driver source
1341 [NETFILTER] Enable connection tracking flow accounting
1342 0 to disable accounting
1343 1 to enable accounting
1344 Default value depends on CONFIG_NF_CT_ACCT that is
1345 going to be removed in 2.6.29.
1348 See Documentation/filesystems/nfsroot.txt.
1350 nfsroot= [NFS] nfs root filesystem for disk-less boxes.
1351 See Documentation/filesystems/nfsroot.txt.
1353 nfs.callback_tcpport=
1354 [NFS] set the TCP port on which the NFSv4 callback
1355 channel should listen.
1357 nfs.idmap_cache_timeout=
1358 [NFS] set the maximum lifetime for idmapper cache
1362 [NFS] enable 64-bit inode numbers.
1363 If zero, the NFS client will fake up a 32-bit inode
1364 number for the readdir() and stat() syscalls instead
1365 of returning the full 64-bit number.
1366 The default is to return 64-bit inode numbers.
1368 nmi_debug= [KNL,AVR32] Specify one or more actions to take
1369 when a NMI is triggered.
1370 Format: [state][,regs][,debounce][,die]
1372 nmi_watchdog= [KNL,BUGS=X86-32] Debugging features for SMP kernels
1374 no387 [BUGS=X86-32] Tells the kernel to use the 387 maths
1375 emulation library even if a 387 maths coprocessor
1378 noaliencache [MM, NUMA, SLAB] Disables the allocation of alien
1379 caches in the slab allocator. Saves per-node memory,
1380 but will impact performance.
1384 noapic [SMP,APIC] Tells the kernel to not make use of any
1385 IOAPICs that may be present in the system.
1387 nobats [PPC] Do not use BATs for mapping kernel lowmem
1388 on "Classic" PPC cores.
1392 nodelayacct [KNL] Disable per-task delay accounting
1394 nodisconnect [HW,SCSI,M68K] Disables SCSI disconnects.
1396 noefi [X86-32,X86-64] Disable EFI runtime services support.
1400 noexec [X86-32,X86-64]
1401 On X86-32 available only on PAE configured kernels.
1402 noexec=on: enable non-executable mappings (default)
1403 noexec=off: disable non-executable mappings
1406 This affects only 32-bit executables.
1407 noexec32=on: enable non-executable mappings (default)
1408 read doesn't imply executable mappings
1409 noexec32=off: disable non-executable mappings
1410 read implies executable mappings
1412 nofxsr [BUGS=X86-32] Disables x86 floating point extended
1413 register save and restore. The kernel will only save
1414 legacy floating-point registers on task switch.
1416 noclflush [BUGS=X86] Don't use the CLFLUSH instruction
1420 no-hlt [BUGS=X86-32] Tells the kernel that the hlt
1421 instruction doesn't work correctly and not to
1424 nohalt [IA-64] Tells the kernel not to use the power saving
1425 function PAL_HALT_LIGHT when idle. This increases
1426 power-consumption. On the positive side, it reduces
1427 interrupt wake-up latency, which may improve performance
1428 in certain environments such as networked servers or
1431 nohz= [KNL] Boottime enable/disable dynamic ticks
1432 Valid arguments: on, off
1435 noirqbalance [X86-32,SMP,KNL] Disable kernel irq balancing
1437 noirqdebug [X86-32] Disables the code which attempts to detect and
1438 disable unhandled interrupt sources.
1440 no_timer_check [X86-32,X86_64,APIC] Disables the code which tests for
1441 broken timer IRQ sources.
1443 noisapnp [ISAPNP] Disables ISA PnP code.
1445 noinitrd [RAM] Tells the kernel not to load any configured
1450 nojitter [IA64] Disables jitter checking for ITC timers.
1452 nolapic [X86-32,APIC] Do not enable or use the local APIC.
1454 nolapic_timer [X86-32,APIC] Do not use the local APIC timer.
1456 nox2apic [X86-64,APIC] Do not enable x2APIC mode.
1458 x2apic_phys [X86-64,APIC] Use x2apic physical mode instead of
1459 default x2apic cluster mode on platforms
1462 noltlbs [PPC] Do not use large page/tlb entries for kernel
1463 lowmem mapping on PPC40x.
1465 nomca [IA-64] Disable machine check abort handling
1467 nomce [X86-32] Machine Check Exception
1469 nomfgpt [X86-32] Disable Multi-Function General Purpose
1470 Timer usage (for AMD Geode machines).
1472 noreplace-paravirt [X86-32,PV_OPS] Don't patch paravirt_ops
1474 noreplace-smp [X86-32,SMP] Don't replace SMP instructions
1475 with UP alternatives
1477 noresidual [PPC] Don't use residual data on PReP machines.
1479 noresume [SWSUSP] Disables resume and restores original swap
1482 no-scroll [VGA] Disables scrollback.
1483 This is required for the Braillex ib80-piezo Braille
1484 reader made by F.H. Papenmeier (Germany).
1488 nosep [BUGS=X86-32] Disables x86 SYSENTER/SYSEXIT support.
1490 nosmp [SMP] Tells an SMP kernel to act as a UP kernel,
1491 and disable the IO APIC. legacy for "maxcpus=0".
1493 nosoftlockup [KNL] Disable the soft-lockup detector.
1495 nosync [HW,M68K] Disables sync negotiation for all devices.
1497 notsc [BUGS=X86-32] Disable Time Stamp Counter
1499 nousb [USB] Disable the USB subsystem
1503 nptcg= [IA64] Override max number of concurrent global TLB
1504 purges which is reported from either PAL_VM_SUMMARY or
1507 numa_zonelist_order= [KNL, BOOT] Select zonelist order for NUMA.
1508 one of ['zone', 'node', 'default'] can be specified
1509 This can be set from sysctl after boot.
1510 See Documentation/sysctl/vm.txt for details.
1512 nr_uarts= [SERIAL] maximum number of UARTs to be registered.
1514 olpc_ec_timeout= [OLPC] ms delay when issuing EC commands
1515 Rather than timing out after 20 ms if an EC
1516 command is not properly ACKed, override the length
1517 of the timeout. We have interrupts disabled while
1518 waiting for the ACK, so if this is set too high
1519 interrupts *may* be lost!
1524 oprofile.timer= [HW]
1525 Use timer interrupt instead of performance counters
1527 osst= [HW,SCSI] SCSI Tape Driver
1528 Format: <buffer_size>,<write_threshold>
1529 See also Documentation/scsi/st.txt.
1531 panic= [KNL] Kernel behaviour on panic
1534 parkbd.port= [HW] Parallel port number the keyboard adapter is
1535 connected to, default is 0.
1537 parkbd.mode= [HW] Parallel port keyboard adapter mode of operation,
1538 0 for XT, 1 for AT (default is AT).
1541 parport= [HW,PPT] Specify parallel ports. 0 disables.
1542 Format: { 0 | auto | 0xBBB[,IRQ[,DMA]] }
1543 Use 'auto' to force the driver to use any
1544 IRQ/DMA settings detected (the default is to
1545 ignore detected IRQ/DMA settings because of
1546 possible conflicts). You can specify the base
1547 address, IRQ, and DMA settings; IRQ and DMA
1548 should be numbers, or 'auto' (for using detected
1549 settings on that particular port), or 'nofifo'
1550 (to avoid using a FIFO even if it is detected).
1551 Parallel ports are assigned in the order they
1552 are specified on the command line, starting
1555 parport_init_mode= [HW,PPT]
1556 Configure VIA parallel port to operate in
1557 a specific mode. This is necessary on Pegasos
1558 computer where firmware has no options for setting
1559 up parallel port mode and sets it to spp.
1560 Currently this function knows 686a and 8231 chips.
1561 Format: [spp|ps2|epp|ecp|ecpepp]
1563 pas2= [HW,OSS] Format:
1564 <io>,<irq>,<dma>,<dma16>,<sb_io>,<sb_irq>,<sb_dma>,<sb_dma16>
1567 See header of drivers/scsi/pas16.c.
1570 Halt all CPUs after the first oops has been printed for
1571 the specified number of seconds. This is to be used if
1572 your oopses keep scrolling off the screen.
1577 See header of drivers/block/paride/pcd.c.
1578 See also Documentation/paride.txt.
1580 pci=option[,option...] [PCI] various PCI subsystem options:
1581 off [X86-32] don't probe for the PCI bus
1582 bios [X86-32] force use of PCI BIOS, don't access
1583 the hardware directly. Use this if your machine
1584 has a non-standard PCI host bridge.
1585 nobios [X86-32] disallow use of PCI BIOS, only direct
1586 hardware access methods are allowed. Use this
1587 if you experience crashes upon bootup and you
1588 suspect they are caused by the BIOS.
1589 conf1 [X86-32] Force use of PCI Configuration
1591 conf2 [X86-32] Force use of PCI Configuration
1593 noaer [PCIE] If the PCIEAER kernel config parameter is
1594 enabled, this kernel boot option can be used to
1595 disable the use of PCIE advanced error reporting.
1596 nodomains [PCI] Disable support for multiple PCI
1597 root domains (aka PCI segments, in ACPI-speak).
1598 nommconf [X86-32,X86_64] Disable use of MMCONFIG for PCI
1600 nomsi [MSI] If the PCI_MSI kernel config parameter is
1601 enabled, this kernel boot option can be used to
1602 disable the use of MSI interrupts system-wide.
1603 biosirq [X86-32] Use PCI BIOS calls to get the interrupt
1604 routing table. These calls are known to be buggy
1605 on several machines and they hang the machine
1606 when used, but on other computers it's the only
1607 way to get the interrupt routing table. Try
1608 this option if the kernel is unable to allocate
1609 IRQs or discover secondary PCI buses on your
1611 rom [X86-32] Assign address space to expansion ROMs.
1612 Use with caution as certain devices share
1613 address decoders between ROMs and other
1615 norom [X86-32,X86_64] Do not assign address space to
1616 expansion ROMs that do not already have
1617 BIOS assigned address ranges.
1618 irqmask=0xMMMM [X86-32] Set a bit mask of IRQs allowed to be
1619 assigned automatically to PCI devices. You can
1620 make the kernel exclude IRQs of your ISA cards
1622 pirqaddr=0xAAAAA [X86-32] Specify the physical address
1623 of the PIRQ table (normally generated
1624 by the BIOS) if it is outside the
1625 F0000h-100000h range.
1626 lastbus=N [X86-32] Scan all buses thru bus #N. Can be
1627 useful if the kernel is unable to find your
1628 secondary buses and you want to tell it
1629 explicitly which ones they are.
1630 assign-busses [X86-32] Always assign all PCI bus
1631 numbers ourselves, overriding
1632 whatever the firmware may have done.
1633 usepirqmask [X86-32] Honor the possible IRQ mask stored
1634 in the BIOS $PIR table. This is needed on
1635 some systems with broken BIOSes, notably
1636 some HP Pavilion N5400 and Omnibook XE3
1637 notebooks. This will have no effect if ACPI
1638 IRQ routing is enabled.
1639 noacpi [X86-32] Do not use ACPI for IRQ routing
1640 or for PCI scanning.
1641 use_crs [X86-32] Use _CRS for PCI resource
1643 routeirq Do IRQ routing for all PCI devices.
1644 This is normally done in pci_enable_device(),
1645 so this option is a temporary workaround
1646 for broken drivers that don't call it.
1647 skip_isa_align [X86] do not align io start addr, so can
1648 handle more pci cards
1649 firmware [ARM] Do not re-enumerate the bus but instead
1650 just use the configuration from the
1651 bootloader. This is currently used on
1652 IXP2000 systems where the bus has to be
1653 configured a certain way for adjunct CPUs.
1654 noearly [X86] Don't do any early type 1 scanning.
1655 This might help on some broken boards which
1656 machine check when some devices' config space
1657 is read. But various workarounds are disabled
1658 and some IOMMU drivers will not work.
1659 bfsort Sort PCI devices into breadth-first order.
1660 This sorting is done to get a device
1661 order compatible with older (<= 2.4) kernels.
1662 nobfsort Don't sort PCI devices into breadth-first order.
1663 cbiosize=nn[KMG] The fixed amount of bus space which is
1664 reserved for the CardBus bridge's IO window.
1665 The default value is 256 bytes.
1666 cbmemsize=nn[KMG] The fixed amount of bus space which is
1667 reserved for the CardBus bridge's memory
1668 window. The default value is 64 megabytes.
1670 pcmv= [HW,PCMCIA] BadgePAD 4
1673 See Documentation/paride.txt.
1675 pdcchassis= [PARISC,HW] Disable/Enable PDC Chassis Status codes at
1678 See arch/parisc/kernel/pdc_chassis.c
1681 See Documentation/paride.txt.
1684 See Documentation/paride.txt.
1686 pirq= [SMP,APIC] Manual mp-table setup
1687 See Documentation/i386/IO-APIC.txt.
1689 plip= [PPT,NET] Parallel port network link
1690 Format: { parport<nr> | timid | 0 }
1691 See also Documentation/parport.txt.
1693 pmtmr= [X86] Manual setup of pmtmr I/O Port.
1694 Override pmtimer IOPort with a hex value.
1701 { on | off | curr | res | no-curr | no-res }
1704 [ISAPNP] Exclude IRQs for the autoconfiguration
1707 [ISAPNP] Exclude DMAs for the autoconfiguration
1709 pnp_reserve_io= [ISAPNP] Exclude I/O ports for the autoconfiguration
1710 Ranges are in pairs (I/O port base and size).
1713 [ISAPNP] Exclude memory regions for the
1715 Ranges are in pairs (memory base and size).
1718 Enables pr_debug()/dev_dbg() calls if
1719 CONFIG_DYNAMIC_PRINTK_DEBUG has been enabled. These can also
1720 be switched on/off via <debugfs>/dynamic_printk/modules
1722 print-fatal-signals=
1723 [KNL] debug: print fatal signals
1724 print-fatal-signals=1: print segfault info to
1728 printk.time= Show timing data prefixed to each printk message line
1729 Format: <bool> (1/Y/y=enable, 0/N/n=disable)
1731 profile= [KNL] Enable kernel profiling via /proc/profile
1732 Format: [schedule,]<number>
1733 Param: "schedule" - profile schedule points.
1734 Param: <number> - step/bucket size as a power of 2 for
1735 statistical time based profiling.
1736 Param: "sleep" - profile D-state sleeping (millisecs).
1737 Requires CONFIG_SCHEDSTATS
1738 Param: "kvm" - profile VM exits.
1740 processor.max_cstate= [HW,ACPI]
1741 Limit processor to maximum C-state
1742 max_cstate=9 overrides any DMI blacklist limit.
1744 processor.nocst [HW,ACPI]
1745 Ignore the _CST method to determine C-states,
1746 instead using the legacy FADT method
1748 prompt_ramdisk= [RAM] List of RAM disks to prompt for floppy disk
1750 See Documentation/ramdisk.txt.
1752 psmouse.proto= [HW,MOUSE] Highest PS2 mouse protocol extension to
1753 probe for; one of (bare|imps|exps|lifebook|any).
1754 psmouse.rate= [HW,MOUSE] Set desired mouse report rate, in reports
1756 psmouse.resetafter= [HW,MOUSE]
1757 Try to reset the device after so many bad packets
1760 [HW,MOUSE] Set desired mouse resolution, in dpi.
1761 psmouse.smartscroll=
1762 [HW,MOUSE] Controls Logitech smartscroll autorepeat.
1763 0 = disabled, 1 = enabled (default).
1765 pss= [HW,OSS] Personal Sound System (ECHO ESC614)
1767 <io>,<mss_io>,<mss_irq>,<mss_dma>,<mpu_io>,<mpu_irq>
1770 See Documentation/paride.txt.
1773 [KNL] Number of legacy pty's. Overwrites compiled-in
1776 quiet [KNL] Disable most log messages
1781 See Documentation/md.txt.
1783 ramdisk_blocksize= [RAM]
1784 See Documentation/ramdisk.txt.
1786 ramdisk_size= [RAM] Sizes of RAM disks in kilobytes
1787 See Documentation/ramdisk.txt.
1789 rcupdate.blimit= [KNL,BOOT]
1790 Set maximum number of finished RCU callbacks to process
1793 rcupdate.qhimark= [KNL,BOOT]
1794 Set threshold of queued
1795 RCU callbacks over which batch limiting is disabled.
1797 rcupdate.qlowmark= [KNL,BOOT]
1798 Set threshold of queued RCU callbacks below which
1799 batch limiting is re-enabled.
1803 Run specified binary instead of /init from the ramdisk,
1804 used for early userspace startup. See initrd.
1806 reboot= [BUGS=X86-32,BUGS=ARM,BUGS=IA-64] Rebooting mode
1807 Format: <reboot_mode>[,<reboot_mode2>[,...]]
1808 See arch/*/kernel/reboot.c or arch/*/kernel/process.c
1811 [KNL, SMP] Set scheduler's default relax_domain_level.
1812 See Documentation/cpusets.txt.
1814 reserve= [KNL,BUGS] Force the kernel to ignore some iomem area
1816 reservetop= [X86-32]
1818 Reserves a hole at the top of the kernel virtual
1821 reset_devices [KNL] Force drivers to reset the underlying device
1822 during initialization.
1825 Specify the partition device for software suspend
1827 resume_offset= [SWSUSP]
1828 Specify the offset from the beginning of the partition
1829 given by "resume=" at which the swap header is located,
1830 in <PAGE_SIZE> units (needed only for swap files).
1831 See Documentation/power/swsusp-and-swap-files.txt
1833 retain_initrd [RAM] Keep initrd memory after extraction
1835 rhash_entries= [KNL,NET]
1836 Set number of hash buckets for route cache
1838 riscom8= [HW,SERIAL]
1839 Format: <io_board1>[,<io_board2>[,...<io_boardN>]]
1841 ro [KNL] Mount root device read-only on boot
1843 root= [KNL] Root filesystem
1845 rootdelay= [KNL] Delay (in seconds) to pause before attempting to
1846 mount the root filesystem
1848 rootflags= [KNL] Set root filesystem mount option string
1850 rootfstype= [KNL] Set root filesystem type
1852 rootwait [KNL] Wait (indefinitely) for root device to show up.
1853 Useful for devices that are detected asynchronously
1854 (e.g. USB and MMC devices).
1856 root_plug.vendor_id=
1857 [ROOTPLUG] Override the default vendor ID
1859 root_plug.product_id=
1860 [ROOTPLUG] Override the default product ID
1863 [ROOTPLUG] Enable debugging output
1865 rw [KNL] Mount root device read-write on boot
1867 S [KNL] Run init in single mode
1870 See drivers/net/irda/sa1100_ir.c.
1872 sbni= [NET] Granch SBNI12 leased line adapter
1874 sc1200wdt= [HW,WDT] SC1200 WDT (watchdog) driver
1875 Format: <io>[,<timeout>[,<isapnp>]]
1877 scsi_debug_*= [SCSI]
1878 See drivers/scsi/scsi_debug.c.
1880 scsi_default_dev_flags=
1881 [SCSI] SCSI default device flags
1884 scsi_dev_flags= [SCSI] Black/white list entry for vendor and model
1885 Format: <vendor>:<model>:<flags>
1886 (flags are integer value)
1888 scsi_logging_level= [SCSI] a bit mask of logging levels
1889 See drivers/scsi/scsi_logging.h for bits. Also
1890 settable via sysctl at dev.scsi.logging_level
1891 (/proc/sys/dev/scsi/logging_level).
1892 There is also a nice 'scsi_logging_level' script in the
1893 S390-tools package, available for download at
1894 http://www-128.ibm.com/developerworks/linux/linux390/s390-tools-1.5.4.html
1896 scsi_mod.scan= [SCSI] sync (default) scans SCSI busses as they are
1897 discovered. async scans them in kernel threads,
1898 allowing boot to proceed. none ignores them, expecting
1899 user space to do the scan.
1901 selinux [SELINUX] Disable or enable SELinux at boot time.
1902 Format: { "0" | "1" }
1903 See security/selinux/Kconfig help text.
1906 Default value is set via kernel config option.
1907 If enabled at boot time, /selinux/disable can be used
1908 later to disable prior to initial policy load.
1910 selinux_compat_net =
1911 [SELINUX] Set initial selinux_compat_net flag value.
1912 Format: { "0" | "1" }
1913 0 -- use new secmark-based packet controls
1914 1 -- use legacy packet controls
1915 Default value is 0 (preferred).
1916 Value can be changed at runtime via
1917 /selinux/compat_net.
1919 serialnumber [BUGS=X86-32]
1922 Maximal number of shapers.
1924 show_msr= [x86] show boot-time MSR settings
1925 Format: { <integer> }
1926 Show boot-time (BIOS-initialized) MSR settings.
1927 The parameter means the number of CPUs to show,
1928 for example 1 means boot CPU only.
1931 See header of drivers/scsi/sim710.c.
1938 slub_debug[=options[,slabs]] [MM, SLUB]
1939 Enabling slub_debug allows one to determine the
1940 culprit if slab objects become corrupted. Enabling
1941 slub_debug can create guard zones around objects and
1942 may poison objects when not in use. Also tracks the
1943 last alloc / free. For more information see
1944 Documentation/vm/slub.txt.
1946 slub_max_order= [MM, SLUB]
1947 Determines the maximum allowed order for slabs.
1948 A high setting may cause OOMs due to memory
1949 fragmentation. For more information see
1950 Documentation/vm/slub.txt.
1952 slub_min_objects= [MM, SLUB]
1953 The minimum number of objects per slab. SLUB will
1954 increase the slab order up to slub_max_order to
1955 generate a sufficiently large slab able to contain
1956 the number of objects indicated. The higher the number
1957 of objects the smaller the overhead of tracking slabs
1958 and the less frequently locks need to be acquired.
1959 For more information see Documentation/vm/slub.txt.
1961 slub_min_order= [MM, SLUB]
1962 Determines the mininum page order for slabs. Must be
1963 lower than slub_max_order.
1964 For more information see Documentation/vm/slub.txt.
1966 slub_nomerge [MM, SLUB]
1967 Disable merging of slabs with similar size. May be
1968 necessary if there is some reason to distinguish
1969 allocs to different slabs. Debug options disable
1970 merging on their own.
1971 For more information see Documentation/vm/slub.txt.
1974 Format: <io1>[,<io2>[,...,<io8>]]
1976 smp-alt-once [X86-32,SMP] On a hotplug CPU system, only
1977 attempt to substitute SMP alternatives once at boot.
1979 smsc-ircc2.nopnp [HW] Don't use PNP to discover SMC devices
1980 smsc-ircc2.ircc_cfg= [HW] Device configuration I/O port
1981 smsc-ircc2.ircc_sir= [HW] SIR base I/O port
1982 smsc-ircc2.ircc_fir= [HW] FIR base I/O port
1983 smsc-ircc2.ircc_irq= [HW] IRQ line
1984 smsc-ircc2.ircc_dma= [HW] DMA channel
1985 smsc-ircc2.ircc_transceiver= [HW] Transceiver type:
1986 0: Toshiba Satellite 1800 (GP data pin select)
1987 1: Fast pin select (default)
1990 snd-ad1816a= [HW,ALSA]
1992 snd-ad1848= [HW,ALSA]
1994 snd-ali5451= [HW,ALSA]
1996 snd-als100= [HW,ALSA]
1998 snd-als4000= [HW,ALSA]
2000 snd-azt2320= [HW,ALSA]
2002 snd-cmi8330= [HW,ALSA]
2004 snd-cmipci= [HW,ALSA]
2006 snd-cs4231= [HW,ALSA]
2008 snd-cs4232= [HW,ALSA]
2010 snd-cs4236= [HW,ALSA]
2012 snd-cs4281= [HW,ALSA]
2014 snd-cs46xx= [HW,ALSA]
2016 snd-dt019x= [HW,ALSA]
2018 snd-dummy= [HW,ALSA]
2020 snd-emu10k1= [HW,ALSA]
2022 snd-ens1370= [HW,ALSA]
2024 snd-ens1371= [HW,ALSA]
2026 snd-es968= [HW,ALSA]
2028 snd-es1688= [HW,ALSA]
2030 snd-es18xx= [HW,ALSA]
2032 snd-es1938= [HW,ALSA]
2034 snd-es1968= [HW,ALSA]
2036 snd-fm801= [HW,ALSA]
2038 snd-gusclassic= [HW,ALSA]
2040 snd-gusextreme= [HW,ALSA]
2042 snd-gusmax= [HW,ALSA]
2046 snd-ice1712= [HW,ALSA]
2048 snd-intel8x0= [HW,ALSA]
2050 snd-interwave= [HW,ALSA]
2055 snd-korg1212= [HW,ALSA]
2057 snd-maestro3= [HW,ALSA]
2059 snd-mpu401= [HW,ALSA]
2061 snd-mtpav= [HW,ALSA]
2063 snd-nm256= [HW,ALSA]
2065 snd-opl3sa2= [HW,ALSA]
2073 snd-opti93x= [HW,ALSA]
2077 snd-rme32= [HW,ALSA]
2079 snd-rme96= [HW,ALSA]
2081 snd-rme9652= [HW,ALSA]
2087 snd-sbawe= [HW,ALSA]
2089 snd-serial= [HW,ALSA]
2091 snd-sgalaxy= [HW,ALSA]
2093 snd-sonicvibes= [HW,ALSA]
2098 snd-sun-cs4231= [HW,ALSA]
2100 snd-trident= [HW,ALSA]
2102 snd-usb-audio= [HW,ALSA,USB]
2104 snd-via82xx= [HW,ALSA]
2106 snd-virmidi= [HW,ALSA]
2108 snd-wavefront= [HW,ALSA]
2110 snd-ymfpci= [HW,ALSA]
2113 [KNL] Should the soft-lockup detector generate panics.
2115 sonypi.*= [HW] Sony Programmable I/O Control Device driver
2116 See Documentation/sonypi.txt
2118 specialix= [HW,SERIAL] Specialix multi-serial port adapter
2119 See Documentation/specialix.txt.
2121 spia_io_base= [HW,MTD]
2127 Format: <io>,<irq>,<dma>,<mpu_io>,<mpu_irq>
2129 st= [HW,SCSI] SCSI tape parameters (buffers, etc.)
2130 See Documentation/scsi/st.txt.
2134 Set the STI (builtin display/keyboard on the HP-PARISC
2135 machines) console (graphic card) which should be used
2136 as the initial boot-console.
2137 See also comment in drivers/video/console/sticore.c.
2140 See comment in drivers/video/console/sticore.c.
2143 Format: bpp:<bpp1>[:<bpp2>[:<bpp3>...]]
2147 Control how the NFS server code allocates CPUs to
2148 service thread pools. Depending on how many NICs
2149 you have and where their interrupts are bound, this
2150 option will affect which CPUs will do NFS serving.
2151 Note: this parameter cannot be changed while the
2152 NFS server is running.
2154 auto the server chooses an appropriate mode
2155 automatically using heuristics
2156 global a single global pool contains all CPUs
2157 percpu one pool for each CPU
2158 pernode one pool for each NUMA node (equivalent
2159 to global on non-NUMA machines)
2161 swiotlb= [IA-64] Number of I/O TLB slabs
2165 sym53c416= [HW,SCSI]
2166 See header of drivers/scsi/sym53c416.c.
2168 sysrq_always_enabled
2170 Ignore sysrq setting - this boot parameter will
2171 neutralize any effect of /proc/sys/kernel/sysrq.
2172 Useful for debugging.
2175 See header of drivers/scsi/t128.c.
2179 test_suspend= [SUSPEND]
2180 Specify "mem" (for Suspend-to-RAM) or "standby" (for
2181 standby suspend) as the system sleep state to briefly
2182 enter during system startup. The system is woken from
2183 this state using a wakeup-capable RTC alarm.
2185 thash_entries= [KNL,NET]
2186 Set number of hash buckets for TCP connection
2188 thermal.act= [HW,ACPI]
2189 -1: disable all active trip points in all thermal zones
2190 <degrees C>: override all lowest active trip points
2192 thermal.crt= [HW,ACPI]
2193 -1: disable all critical trip points in all thermal zones
2194 <degrees C>: lower all critical trip points
2196 thermal.nocrt= [HW,ACPI]
2197 Set to disable actions on ACPI thermal zone
2198 critical and hot trip points.
2200 thermal.off= [HW,ACPI]
2201 1: disable ACPI thermal control
2203 thermal.psv= [HW,ACPI]
2204 -1: disable all passive trip points
2205 <degrees C>: override all passive trip points to this value
2207 thermal.tzp= [HW,ACPI]
2208 Specify global default ACPI thermal zone polling rate
2209 <deci-seconds>: poll all this frequency
2210 0: no polling (default)
2213 See comment before function dc390_setup() in
2214 drivers/scsi/tmscsim.c.
2218 trix= [HW,OSS] MediaTrix AudioTrix Pro
2220 <io>,<irq>,<dma>,<dma2>,<sb_io>,<sb_irq>,<sb_dma>,<mpu_io>,<mpu_irq>
2222 turbografx.map[2|3]= [HW,JOY]
2223 TurboGraFX parallel port interface
2225 <port#>,<js1>,<js2>,<js3>,<js4>,<js5>,<js6>,<js7>
2226 See also Documentation/input/joystick-parport.txt
2228 u14-34f= [HW,SCSI] UltraStor 14F/34F SCSI host adapter
2229 See header of drivers/scsi/u14-34f.c.
2238 [USB] Ignore overcurrent events (default N).
2239 Some badly-designed motherboards generate lots of
2240 bogus events, for ports that aren't wired to
2241 anything. Set this parameter to avoid log spamming.
2242 Note that genuine overcurrent events won't be
2247 Set unknown_nmi_panic=1 early on boot.
2249 usbcore.autosuspend=
2250 [USB] The autosuspend time delay (in seconds) used
2251 for newly-detected USB devices (default 2). This
2252 is the time required before an idle device will be
2253 autosuspended. Devices for which the delay is set
2254 to a negative value won't be autosuspended at all.
2257 [USBHID] The interval which mice are to be polled at.
2259 add_efi_memmap [EFI; x86-32,X86-64] Include EFI memory map in
2260 kernel's map of available physical RAM.
2262 vdso= [X86-32,SH,x86-64]
2263 vdso=2: enable compat VDSO (default with COMPAT_VDSO)
2264 vdso=1: enable VDSO (default)
2265 vdso=0: disable VDSO mapping
2267 vdso32= [X86-32,X86-64]
2268 vdso32=2: enable compat VDSO (default with COMPAT_VDSO)
2269 vdso32=1: enable 32-bit VDSO (default)
2270 vdso32=0: disable 32-bit VDSO mapping
2273 vector=percpu: enable percpu vector domain
2275 video= [FB] Frame buffer configuration
2276 See Documentation/fb/modedb.txt.
2278 vga= [BOOT,X86-32] Select a particular video mode
2279 See Documentation/i386/boot.txt and
2280 Documentation/svga.txt.
2281 Use vga=ask for menu.
2282 This is actually a boot loader parameter; the value is
2283 passed to the kernel using a special protocol.
2285 vmalloc=nn[KMG] [KNL,BOOT] Forces the vmalloc area to have an exact
2286 size of <nn>. This can be used to increase the
2287 minimum size (128MB on x86). It can also be used to
2288 decrease the size and leave more room for directly
2291 vmhalt= [KNL,S390] Perform z/VM CP command after system halt.
2294 vmpanic= [KNL,S390] Perform z/VM CP command after kernel panic.
2297 vmpoff= [KNL,S390] Perform z/VM CP command after power off.
2300 waveartist= [HW,OSS]
2301 Format: <io>,<irq>,<dma>,<dma2>
2304 See header of drivers/scsi/wd33c93.c.
2307 See header of drivers/scsi/wd7000.c.
2310 See Documentation/watchdog/wdt.txt.
2312 xd= [HW,XT] Original XT pre-IDE (RLL encoded) disks.
2313 xd_geo= See header of drivers/block/xd.c.
2315 xirc2ps_cs= [NET,PCMCIA]
2317 <irq>,<irq_mask>,<io>,<full_duplex>,<do_sound>,<lockup_hack>[,<irq2>[,<irq3>[,<irq4>]]]
2319 norandmaps Don't use address space randomization
2320 Equivalent to echo 0 > /proc/sys/kernel/randomize_va_space
2322 ______________________________________________________________________
2326 Add documentation for ALSA options.
2327 Add more DRM drivers.
projects / linux-2.6 / blob