4 The following is a consolidated list of the kernel parameters as implemented
5 (mostly) by the __setup() macro and sorted into English Dictionary order
6 (defined as ignoring all punctuation and sorting digits before letters in a
7 case insensitive manner), and with descriptions where known.
9 Module parameters for loadable modules are specified only as the
10 parameter name with optional '=' and value as appropriate, such as:
12 modprobe usbcore blinkenlights=1
14 Module parameters for modules that are built into the kernel image
15 are specified on the kernel command line with the module name plus
16 '.' plus parameter name, with '=' and value if appropriate, such as:
18 usbcore.blinkenlights=1
20 This document may not be entirely up to date and comprehensive. The command
21 "modinfo -p ${modulename}" shows a current list of all parameters of a loadable
22 module. Loadable modules, after being loaded into the running kernel, also
23 reveal their parameters in /sys/module/${modulename}/parameters/. Some of these
24 parameters may be changed at runtime by the command
25 "echo -n ${value} > /sys/module/${modulename}/parameters/${parm}".
27 The parameters listed below are only valid if certain kernel build options were
28 enabled and if respective hardware is present. The text in square brackets at
29 the beginning of each description states the restrictions within which a
30 parameter is applicable:
32 ACPI ACPI support is enabled.
33 AGP AGP (Accelerated Graphics Port) is enabled.
34 ALSA ALSA sound support is enabled.
35 APIC APIC support is enabled.
36 APM Advanced Power Management support is enabled.
37 AVR32 AVR32 architecture is enabled.
38 AX25 Appropriate AX.25 support is enabled.
39 BLACKFIN Blackfin architecture is enabled.
40 DRM Direct Rendering Management support is enabled.
41 EDD BIOS Enhanced Disk Drive Services (EDD) is enabled
42 EFI EFI Partitioning (GPT) is enabled
43 EIDE EIDE/ATAPI support is enabled.
44 FB The frame buffer device is enabled.
45 HW Appropriate hardware is enabled.
46 IA-64 IA-64 architecture is enabled.
47 IOSCHED More than one I/O scheduler is enabled.
48 IP_PNP IP DHCP, BOOTP, or RARP is enabled.
49 ISAPNP ISA PnP code is enabled.
50 ISDN Appropriate ISDN support is enabled.
51 JOY Appropriate joystick support is enabled.
52 LIBATA Libata driver is enabled
53 LP Printer support is enabled.
54 LOOP Loopback device support is enabled.
55 M68k M68k architecture is enabled.
56 These options have more detailed description inside of
57 Documentation/m68k/kernel-options.txt.
58 MCA MCA bus support is enabled.
59 MDA MDA console support is enabled.
60 MOUSE Appropriate mouse support is enabled.
61 MSI Message Signaled Interrupts (PCI).
62 MTD MTD (Memory Technology Device) support is enabled.
63 NET Appropriate network support is enabled.
64 NUMA NUMA support is enabled.
65 GENERIC_TIME The generic timeofday code is enabled.
66 NFS Appropriate NFS support is enabled.
67 OSS OSS sound support is enabled.
68 PV_OPS A paravirtualized kernel is enabled.
69 PARIDE The ParIDE (parallel port IDE) subsystem is enabled.
70 PARISC The PA-RISC architecture is enabled.
71 PCI PCI bus support is enabled.
72 PCIE PCI Express support is enabled.
73 PCMCIA The PCMCIA subsystem is enabled.
74 PNP Plug & Play support is enabled.
75 PPC PowerPC architecture is enabled.
76 PPT Parallel port support is enabled.
77 PS2 Appropriate PS/2 support is enabled.
78 RAM RAM disk support is enabled.
79 ROOTPLUG The example Root Plug LSM is enabled.
80 S390 S390 architecture is enabled.
81 SCSI Appropriate SCSI support is enabled.
82 A lot of drivers has their options described inside of
84 SECURITY Different security models are enabled.
85 SELINUX SELinux support is enabled.
86 SERIAL Serial support is enabled.
87 SH SuperH architecture is enabled.
88 SMP The kernel is an SMP kernel.
89 SPARC Sparc architecture is enabled.
90 SWSUSP Software suspend (hibernation) is enabled.
91 SUSPEND System suspend states are enabled.
92 TS Appropriate touchscreen support is enabled.
93 USB USB support is enabled.
94 USBHID USB Human Interface Device support is enabled.
95 V4L Video For Linux support is enabled.
96 VGA The VGA console has been enabled.
97 VT Virtual terminal support is enabled.
98 WDT Watchdog support is enabled.
99 XT IBM PC/XT MFM hard disk support is enabled.
100 X86-32 X86-32, aka i386 architecture is enabled.
101 X86-64 X86-64 architecture is enabled.
102 More X86-64 boot options can be found in
103 Documentation/x86_64/boot-options.txt .
105 In addition, the following text indicates that the option:
107 BUGS= Relates to possible processor bugs on the said processor.
108 KNL Is a kernel start-up parameter.
109 BOOT Is a boot loader parameter.
111 Parameters denoted with BOOT are actually interpreted by the boot
112 loader, and have no meaning to the kernel directly.
113 Do not modify the syntax of boot loader parameters without extreme
114 need or coordination with <Documentation/i386/boot.txt>.
116 There are also arch-specific kernel-parameters not documented here.
117 See for example <Documentation/x86_64/boot-options.txt>.
119 Note that ALL kernel parameters listed below are CASE SENSITIVE, and that
120 a trailing = on the name of any parameter states that that parameter will
121 be entered as an environment variable, whereas its absence indicates that
122 it will appear as a kernel argument readable via /proc/cmdline by programs
123 running once the system is up.
125 The number of kernel parameters is not limited, but the length of the
126 complete command line (parameters including spaces etc.) is limited to
127 a fixed number of characters. This limit depends on the architecture
128 and is between 256 and 4096 characters. It is defined in the file
129 ./include/asm/setup.h as COMMAND_LINE_SIZE.
132 acpi= [HW,ACPI,X86-64,i386]
133 Advanced Configuration and Power Interface
134 Format: { force | off | ht | strict | noirq }
135 force -- enable ACPI if default was off
136 off -- disable ACPI if default was on
137 noirq -- do not use ACPI for IRQ routing
138 ht -- run only enough ACPI to enable Hyper Threading
139 strict -- Be less tolerant of platforms that are not
140 strictly ACPI specification compliant.
142 See also Documentation/power/pm.txt, pci=noacpi
144 acpi_apic_instance= [ACPI, IOAPIC]
146 2: use 2nd APIC table, if available
147 1,0: use 1st APIC table
150 acpi_sleep= [HW,ACPI] Sleep options
151 Format: { s3_bios, s3_mode, s3_beep, s4_nohwsig, old_ordering }
152 See Documentation/power/video.txt for s3_bios and s3_mode.
153 s3_beep is for debugging; it makes the PC's speaker beep
154 as soon as the kernel's real-mode entry point is called.
155 s4_nohwsig prevents ACPI hardware signature from being
156 used during resume from hibernation.
157 old_ordering causes the ACPI 1.0 ordering of the _PTS
158 control method, wrt putting devices into low power
159 states, to be enforced (the ACPI 2.0 ordering of _PTS is
162 acpi_sci= [HW,ACPI] ACPI System Control Interrupt trigger mode
163 Format: { level | edge | high | low }
165 acpi_irq_balance [HW,ACPI]
166 ACPI will balance active IRQs
169 acpi_irq_nobalance [HW,ACPI]
170 ACPI will not move active IRQs (default)
173 acpi_irq_pci= [HW,ACPI] If irq_balance, clear listed IRQs for
175 Format: <irq>,<irq>...
177 acpi_irq_isa= [HW,ACPI] If irq_balance, mark listed IRQs used by ISA
178 Format: <irq>,<irq>...
180 acpi_no_auto_ssdt [HW,ACPI] Disable automatic loading of SSDT
182 acpi_os_name= [HW,ACPI] Tell ACPI BIOS the name of the OS
183 Format: To spoof as Windows 98: ="Microsoft Windows"
185 acpi_osi= [HW,ACPI] Modify list of supported OS interface strings
186 acpi_osi="string1" # add string1 -- only one string
187 acpi_osi="!string2" # remove built-in string2
188 acpi_osi= # disable all strings
190 acpi_serialize [HW,ACPI] force serialization of AML methods
192 acpi_skip_timer_override [HW,ACPI]
193 Recognize and ignore IRQ0/pin2 Interrupt Override.
194 For broken nForce2 BIOS resulting in XT-PIC timer.
195 acpi_use_timer_override [HW,ACPI}
196 Use timer override. For some broken Nvidia NF5 boards
197 that require a timer override, but don't have
200 acpi.debug_layer= [HW,ACPI]
202 Each bit of the <int> indicates an ACPI debug layer,
203 1: enable, 0: disable. It is useful for boot time
204 debugging. After system has booted up, it can be set
205 via /sys/module/acpi/parameters/debug_layer.
206 CONFIG_ACPI_DEBUG must be enabled for this to produce any output.
207 Available bits (add the numbers together) to enable debug output
208 for specific parts of the ACPI subsystem:
209 0x01 utilities 0x02 hardware 0x04 events 0x08 tables
210 0x10 namespace 0x20 parser 0x40 dispatcher
211 0x80 executer 0x100 resources 0x200 acpica debugger
212 0x400 os services 0x800 acpica disassembler.
213 The number can be in decimal or prefixed with 0x in hex.
214 Warning: Many of these options can produce a lot of
215 output and make your system unusable. Be very careful.
217 acpi.debug_level= [HW,ACPI]
219 Each bit of the <int> indicates an ACPI debug level,
220 1: enable, 0: disable. It is useful for boot time
221 debugging. After system has booted up, it can be set
222 via /sys/module/acpi/parameters/debug_level.
223 CONFIG_ACPI_DEBUG must be enabled for this to produce any output.
224 Available bits (add the numbers together) to enable different
225 debug output levels of the ACPI subsystem:
226 0x01 error 0x02 warn 0x04 init 0x08 debug object
227 0x10 info 0x20 init names 0x40 parse 0x80 load
228 0x100 dispatch 0x200 execute 0x400 names 0x800 operation region
229 0x1000 bfield 0x2000 tables 0x4000 values 0x8000 objects
230 0x10000 resources 0x20000 user requests 0x40000 package.
231 The number can be in decimal or prefixed with 0x in hex.
232 Warning: Many of these options can produce a lot of
233 output and make your system unusable. Be very careful.
235 acpi_pm_good [X86-32,X86-64]
236 Override the pmtimer bug detection: force the kernel
237 to assume that this machine's pmtimer latches its value
238 and always returns good values.
241 { off | try_unsupported }
242 off: disable AGP support
243 try_unsupported: try to drive unsupported chipsets
244 (may crash computer or cause data corruption)
246 enable_timer_pin_1 [i386,x86-64]
247 Enable PIN 1 of APIC timer
248 Can be useful to work around chipset bugs
249 (in particular on some ATI chipsets).
250 The kernel tries to set a reasonable default.
252 disable_timer_pin_1 [i386,x86-64]
253 Disable PIN 1 of APIC timer
254 Can be useful to work around chipset bugs.
257 Format: <io>,<irq>,<dma>,<dma2>,<type>
260 See header of drivers/scsi/advansys.c.
262 advwdt= [HW,WDT] Advantech WDT
263 Format: <iostart>,<iostop>
265 aedsp16= [HW,OSS] Audio Excel DSP 16
266 Format: <io>,<irq>,<dma>,<mss_io>,<mpu_io>,<mpu_irq>
267 See also header of sound/oss/aedsp16.c.
270 See Documentation/scsi/aha152x.txt.
273 Format: <portbase>[,<buson>,<busoff>[,<dmaspeed>]]
276 See Documentation/scsi/aic7xxx.txt.
279 See Documentation/scsi/aic79xx.txt.
281 amd_iommu= [HW,X86-84]
282 Pass parameters to the AMD IOMMU driver in the system.
284 isolate - enable device isolation (each device, as far
285 as possible, will get its own protection
287 amd_iommu_size= [HW,X86-64]
288 Define the size of the aperture for the AMD IOMMU
289 driver. Possible values are:
290 '32M', '64M' (default), '128M', '256M', '512M', '1G'
292 amijoy.map= [HW,JOY] Amiga joystick support
293 Map of devices attached to JOY0DAT and JOY1DAT
295 See also Documentation/kernel/input/joystick.txt
297 analog.map= [HW,JOY] Analog joystick and gamepad support
298 Specifies type or capabilities of an analog joystick
299 connected to one of 16 gameports
300 Format: <type1>,<type2>,..<type16>
303 Power management functions (SPARCstation-4/5 + deriv.)
305 Disable APC CPU standby support. SPARCstation-Fox does
306 not play well with APC CPU idle - disable it if you have
307 APC and your system crashes randomly.
309 apic= [APIC,i386] Advanced Programmable Interrupt Controller
310 Change the output verbosity whilst booting
311 Format: { quiet (default) | verbose | debug }
312 Change the amount of debugging information output
313 when initialising the APIC and IO-APIC components.
315 apm= [APM] Advanced Power Management
316 See header of arch/x86/kernel/apm_32.c.
318 arcrimi= [HW,NET] ARCnet - "RIM I" (entirely mem-mapped) cards
319 Format: <io>,<irq>,<nodeID>
323 atarimouse= [HW,MOUSE] Atari Mouse
325 atascsi= [HW,SCSI] Atari SCSI
327 atkbd.extra= [HW] Enable extra LEDs and keys on IBM RapidAccess,
328 EzKey and similar keyboards
330 atkbd.reset= [HW] Reset keyboard during initialization
332 atkbd.set= [HW] Select keyboard code set
333 Format: <int> (2 = AT (default), 3 = PS/2)
335 atkbd.scroll= [HW] Enable scroll wheel on MS Office and similar
338 atkbd.softraw= [HW] Choose between synthetic and real raw mode
339 Format: <bool> (0 = real, 1 = synthetic (default))
341 atkbd.softrepeat= [HW]
342 Use software keyboard repeat
346 baycom_epp= [HW,AX25]
349 baycom_par= [HW,AX25] BayCom Parallel Port AX.25 Modem
351 See header of drivers/net/hamradio/baycom_par.c.
353 baycom_ser_fdx= [HW,AX25]
354 BayCom Serial Port AX.25 Modem (Full Duplex Mode)
355 Format: <io>,<irq>,<mode>[,<baud>]
356 See header of drivers/net/hamradio/baycom_ser_fdx.c.
358 baycom_ser_hdx= [HW,AX25]
359 BayCom Serial Port AX.25 Modem (Half Duplex Mode)
360 Format: <io>,<irq>,<mode>
361 See header of drivers/net/hamradio/baycom_ser_hdx.c.
363 boot_delay= Milliseconds to delay each printk during boot.
364 Values larger than 10 seconds (10000) are changed to
368 bttv.card= [HW,V4L] bttv (bt848 + bt878 based grabber cards)
369 bttv.radio= Most important insmod options are available as
371 bttv.pll= See Documentation/video4linux/bttv/Insmod-options
372 bttv.tuner= and Documentation/video4linux/bttv/CARDLIST
375 See drivers/scsi/BusLogic.c, comment before function
376 BusLogic_ParseDriverOptions().
378 c101= [NET] Moxa C101 synchronous serial card
380 cachesize= [BUGS=X86-32] Override level 2 CPU cache size detection.
381 Sometimes CPU hardware bugs make them report the cache
382 size incorrectly. The kernel will attempt work arounds
383 to fix known problems, but for some CPUs it is not
384 possible to determine what the correct size should be.
385 This option provides an override for these situations.
387 security= [SECURITY] Choose a security module to enable at boot.
388 If this boot parameter is not specified, only the first
389 security module asking for security registration will be
390 loaded. An invalid security module name will be treated
391 as if no module has been chosen.
394 [SECURITY] Disable capabilities. This would normally
395 be used only if an alternative security model is to be
396 configured. Potentially dangerous and should only be
397 used if you are entirely sure of the consequences.
399 ccw_timeout_log [S390]
400 See Documentation/s390/CommonIO for details.
402 cgroup_disable= [KNL] Disable a particular controller
403 Format: {name of the controller(s) to disable}
404 {Currently supported controllers - "memory"}
406 checkreqprot [SELINUX] Set initial checkreqprot flag value.
407 Format: { "0" | "1" }
408 See security/selinux/Kconfig help text.
409 0 -- check protection applied by kernel (includes
410 any implied execute protection).
411 1 -- check protection requested by application.
412 Default value is set via a kernel config option.
413 Value can be changed at runtime via
414 /selinux/checkreqprot.
417 See Documentation/s390/CommonIO for details.
419 clock= [BUGS=X86-32, HW] gettimeofday clocksource override.
421 Forces specified clocksource (if available) to be used
422 when calculating gettimeofday(). If specified
423 clocksource is not available, it defaults to PIT.
424 Format: { pit | tsc | cyclone | pmtmr }
426 clocksource= [GENERIC_TIME] Override the default clocksource
428 Override the default clocksource and use the clocksource
429 with the name specified.
430 Some clocksource names to choose from, depending on
432 [all] jiffies (this is the base, fallback clocksource)
434 [ARM] imx_timer1,OSTS,netx_timer,mpu_timer2,
435 pxa_timer,timer3,32k_counter,timer0_1
437 [X86-32] pit,hpet,tsc,vmi-timer;
438 scx200_hrt on Geode; cyclone on IBM x440
446 clearcpuid=BITNUM [X86]
447 Disable CPUID feature X for the kernel. See
448 include/asm-x86/cpufeature.h for the valid bit numbers.
449 Note the Linux specific bits are not necessarily
450 stable over kernel options, but the vendor specific
452 Also note that user programs calling CPUID directly
453 or using the feature without checking anything
454 will still see it. This just prevents it from
455 being used by the kernel or shown in /proc/cpuinfo.
456 Also note the kernel might malfunction if you disable
459 code_bytes [IA32/X86_64] How many bytes of object code to print
466 [IA32/X86_64] Disable/Enable interrupt 0 timer routing
467 over the 8254 in addition to over the IO-APIC. The
468 kernel tries to set a sensible default.
470 hpet= [X86-32,HPET] option to control HPET usage
471 Format: { enable (default) | disable | force }
472 disable: disable HPET and use PIT instead
473 force: allow force enabled of undocumented chips (ICH4,
476 com20020= [HW,NET] ARCnet - COM20020 chipset
478 <io>[,<irq>[,<nodeID>[,<backplane>[,<ckp>[,<timeout>]]]]]
480 com90io= [HW,NET] ARCnet - COM90xx chipset (IO-mapped buffers)
484 ARCnet - COM90xx chipset (memory-mapped buffers)
485 Format: <io>[,<irq>[,<memstart>]]
487 condev= [HW,S390] console device
490 console= [KNL] Output console device and options.
492 tty<n> Use the virtual console device <n>.
496 Use the specified serial port. The options are of
497 the form "bbbbpnf", where "bbbb" is the baud rate,
498 "p" is parity ("n", "o", or "e"), "n" is number of
499 bits, and "f" is flow control ("r" for RTS or
500 omit it). Default is "9600n8".
502 See Documentation/serial-console.txt for more
504 Documentation/networking/netconsole.txt for an
507 uart[8250],io,<addr>[,options]
508 uart[8250],mmio,<addr>[,options]
509 Start an early, polled-mode console on the 8250/16550
510 UART at the specified I/O port or MMIO address,
511 switching to the matching ttyS device later. The
512 options are the same as for ttyS, above.
514 If the device connected to the port is not a TTY but a braille
515 device, prepend "brl," before the device type, for instance
517 For now, only VisioBraille is supported.
519 earlycon= [KNL] Output early console device and options.
520 uart[8250],io,<addr>[,options]
521 uart[8250],mmio,<addr>[,options]
522 Start an early, polled-mode console on the 8250/16550
523 UART at the specified I/O port or MMIO address.
524 The options are the same as for ttyS, above.
527 [HW] Never suspend the console
528 Disable suspending of consoles during suspend and
529 hibernate operations. Once disabled, debugging
530 messages can reach various consoles while the rest
531 of the system is being put to sleep (ie, while
532 debugging driver suspend/resume hooks). This may
533 not work reliably with all consoles, but is known
534 to work with serial and VGA consoles.
536 cpcihp_generic= [HW,PCI] Generic port I/O CompactPCI driver
538 <first_slot>,<last_slot>,<port>,<enum_bit>[,<debug>]
540 crashkernel=nn[KMG]@ss[KMG]
541 [KNL] Reserve a chunk of physical memory to
542 hold a kernel to switch to with kexec on panic.
544 crashkernel=range1:size1[,range2:size2,...][@offset]
545 [KNL] Same as above, but depends on the memory
546 in the running system. The syntax of range is
547 start-[end] where start and end are both
548 a memory unit (amount[KMG]). See also
549 Documentation/kdump/kdump.txt for a example.
552 Format: <io>,<irq>,<dma>,<dma2>,<mpuio>,<mpuirq>
557 cs89x0_media= [HW,NET]
558 Format: { rj45 | aui | bnc }
561 See header of drivers/s390/block/dasd_devmap.c.
563 db9.dev[2|3]= [HW,JOY] Multisystem joystick support via parallel port
564 (one device per port)
565 Format: <port#>,<type>
566 See also Documentation/input/joystick-parport.txt
568 debug [KNL] Enable kernel debugging (events log level).
571 [KNL] verbose self-tests
573 Print debugging info while doing the locking API
575 We default to 0 (no extra messages), setting it to
576 1 will print _a lot_ more information - normally
577 only useful to kernel developers.
579 debug_objects [KNL] Enable object debugging
581 debugpat [X86] Enable PAT debugging
583 decnet.addr= [HW,NET]
584 Format: <area>[,<node>]
585 See also Documentation/networking/decnet.txt.
588 Format: <blue0>,<blue1>,<blue2>,...,<blue15>
589 Change the default blue palette of the console.
590 This is a 16-member array composed of values
594 Format: <green0>,<green1>,<green2>,...,<green15>
595 Change the default green palette of the console.
596 This is a 16-member array composed of values
600 Format: <red0>,<red1>,<red2>,...,<red15>
601 Change the default red palette of the console.
602 This is a 16-member array composed of values
608 Set system-wide default UTF-8 mode for all tty's.
609 Default is 1, i.e. UTF-8 mode is enabled for all
610 newly opened terminals.
613 Set number of hash buckets for dentry cache.
616 IO parameters + enable/disable command.
618 digiepca= [HW,SERIAL]
619 See drivers/char/README.epca and
620 Documentation/digiepca.txt.
622 disable_mtrr_cleanup [X86]
623 enable_mtrr_cleanup [X86]
624 The kernel tries to adjust MTRR layout from continuous
625 to discrete, to make X server driver able to add WB
626 entry later. This parameter enables/disables that.
628 mtrr_chunk_size=nn[KMG] [X86]
629 used for mtrr cleanup. It is largest continous chunk
630 that could hold holes aka. UC entries.
632 mtrr_gran_size=nn[KMG] [X86]
633 Used for mtrr cleanup. It is granularity of mtrr block.
635 Large value could prevent small alignment from
638 mtrr_spare_reg_nr=n [X86]
640 Range: 0,7 : spare reg number
642 Used for mtrr cleanup. It is spare mtrr entries number.
643 Set to 2 or more if your graphical card needs more.
645 disable_mtrr_trim [X86, Intel and AMD only]
646 By default the kernel will trim any uncacheable
647 memory out of your available memory pool based on
648 MTRR settings. This parameter disables that behavior,
649 possibly causing your machine to run very slowly.
651 dmasound= [HW,OSS] Sound subsystem buffers
657 earlyprintk= [X86-32,X86-64,SH,BLACKFIN]
659 earlyprintk=serial[,ttySn[,baudrate]]
662 Append ",keep" to not disable it when the real console
665 Only vga or serial or usb debug port at a time.
667 Currently only ttyS0 and ttyS1 are supported.
669 Interaction with the standard serial driver is not
672 The VGA output is eventually overwritten by the real
678 Format: {"off" | "on" | "skip[mbr]"}
680 eisa_irq_edge= [PARISC,HW]
681 See header of drivers/parisc/eisa.c.
684 See comment before function elanfreq_setup() in
685 arch/x86/kernel/cpu/cpufreq/elanfreq.c.
688 Format: {"anticipatory" | "cfq" | "deadline" | "noop"}
689 See Documentation/block/as-iosched.txt and
690 Documentation/block/deadline-iosched.txt for details.
692 elfcorehdr= [X86-32, X86_64]
693 Specifies physical address of start of kernel core
694 image elf header. Generally kexec loader will
695 pass this option to capture kernel.
696 See Documentation/kdump/kdump.txt for details.
698 enforcing [SELINUX] Set initial enforcing status.
700 See security/selinux/Kconfig help text.
701 0 -- permissive (log only, no denials).
702 1 -- enforcing (deny and log).
704 Value can be changed at runtime via /selinux/enforce.
707 Format: <spdif>,[<nomix>,[<amplifier>]]
708 See also header of sound/oss/es1371.c.
710 ether= [HW,NET] Ethernet cards parameters
711 This option is obsoleted by the "netdev=" option, which
712 has equivalent usage. See its documentation for details.
714 eurwdt= [HW,WDT] Eurotech CPU-1220/1410 onboard watchdog.
719 fail_make_request=[KNL]
720 General fault injection mechanism.
721 Format: <interval>,<probability>,<space>,<times>
722 See also /Documentation/fault-injection/.
725 See header of drivers/scsi/fd_mcs.c.
728 See header of drivers/scsi/fdomain.c.
731 See Documentation/floppy.txt.
733 force_pal_cache_flush
734 [IA-64] Avoid check_sal_cache_flush which may hang on
735 buggy SAL_CACHE_FLUSH implementations. Using this
736 parameter will force ia64_sal_cache_flush to call
737 ia64_pal_cache_flush instead of SAL_CACHE_FLUSH.
740 [HW,JOY] Multisystem joystick and NES/SNES/PSX pad
741 support via parallel port (up to 5 devices per port)
742 Format: <port#>,<pad1>,<pad2>,<pad3>,<pad4>,<pad5>
743 See also Documentation/input/joystick-parport.txt
747 gart_fix_e820= [X86_64] disable the fix e820 for K8 GART
752 See header of drivers/scsi/gdth.c.
754 gpt [EFI] Forces disk with valid GPT signature but
755 invalid Protective MBR to be treated as GPT.
759 hashdist= [KNL,NUMA] Large hashes allocated during boot
760 are distributed across NUMA nodes. Defaults on
761 for IA-64, off otherwise.
762 Format: 0 | 1 (for off | on)
764 hcl= [IA-64] SGI's Hardware Graph compatibility layer
766 hd= [EIDE] (E)IDE hard drive subsystem geometry
767 Format: <cyl>,<head>,<sect>
769 highmem=nn[KMG] [KNL,BOOT] forces the highmem zone to have an exact
770 size of <nn>. This works even on boxes that have no
771 highmem otherwise. This also works to reduce highmem
772 size on bigger boxes.
774 highres= [KNL] Enable/disable high resolution timer mode.
775 Valid parameters: "on", "off"
779 See Documentation/isdn/README.HiSax.
781 hugepages= [HW,X86-32,IA-64] HugeTLB pages to allocate at boot.
782 hugepagesz= [HW,IA-64,PPC,X86-64] The size of the HugeTLB pages.
783 On x86-64 and powerpc, this option can be specified
784 multiple times interleaved with hugepages= to reserve
785 huge pages of different sizes. Valid pages sizes on
786 x86-64 are 2M (when the CPU supports "pse") and 1G
787 (when the CPU supports the "pdpe1gb" cpuinfo flag)
788 Note that 1GB pages can only be allocated at boot time
789 using hugepages= and not freed afterwards.
791 [same as hugepagesz=] The size of the default
792 HugeTLB page size. This is the size represented by
793 the legacy /proc/ hugepages APIs, used for SHM, and
794 default size when mounting hugetlbfs filesystems.
795 Defaults to the default architecture's huge page size
798 i8042.direct [HW] Put keyboard port into non-translated mode
799 i8042.dumbkbd [HW] Pretend that controller can only read data from
800 keyboard and cannot control its state
801 (Don't attempt to blink the leds)
802 i8042.noaux [HW] Don't check for auxiliary (== mouse) port
803 i8042.nokbd [HW] Don't check/create keyboard port
804 i8042.noloop [HW] Disable the AUX Loopback command while probing
806 i8042.nomux [HW] Don't check presence of an active multiplexing
808 i8042.nopnp [HW] Don't use ACPIPnP / PnPBIOS to discover KBD/AUX
811 [HW] Frequency with which keyboard LEDs should blink
812 when kernel panics (default is 0.5 sec)
813 i8042.reset [HW] Reset the controller during init and cleanup
814 i8042.unlock [HW] Unlock (ignore) the keylock
818 i8k.ignore_dmi [HW] Continue probing hardware even if DMI data
819 indicates that the driver is running on unsupported
821 i8k.force [HW] Activate i8k driver even if SMM BIOS signature
822 does not match list of supported models.
824 [HW] Report power status in /proc/i8k
825 (disabled by default)
826 i8k.restricted [HW] Allow controlling fans only if SYS_ADMIN
829 ibmmcascsi= [HW,MCA,SCSI] IBM MicroChannel SCSI adapter
830 See Documentation/mca.txt.
833 Format: <io>[,<membase>[,<icn_id>[,<icn_id2>]]]
835 ide= [HW] (E)IDE subsystem
836 Format: ide=nodma or ide=doubler
837 See Documentation/ide/ide.txt.
839 idebus= [HW] (E)IDE subsystem - VLB/PCI bus speed
840 See Documentation/ide/ide.txt.
843 Format: idle=poll or idle=mwait, idle=halt, idle=nomwait
844 Poll forces a polling idle loop that can slightly improves the performance
845 of waking up a idle CPU, but will use a lot of power and make the system
846 run hot. Not recommended.
847 idle=mwait. On systems which support MONITOR/MWAIT but the kernel chose
848 to not use it because it doesn't save as much power as a normal idle
849 loop use the MONITOR/MWAIT idle loop anyways. Performance should be the same
851 idle=halt. Halt is forced to be used for CPU idle.
852 In such case C2/C3 won't be used again.
853 idle=nomwait. Disable mwait for CPU C-states
855 ide-pci-generic.all-generic-ide [HW] (E)IDE subsystem
856 Claim all unknown PCI IDE storage controllers.
858 ignore_loglevel [KNL]
859 Ignore loglevel setting - this will print /all/
860 kernel messages to the console. Useful for debugging.
863 Set number of hash buckets for inode cache.
866 See header of drivers/scsi/in2000.c.
870 Run specified binary instead of /sbin/init as init
873 initcall_debug [KNL] Trace initcalls as they are executed. Useful
874 for working out where the kernel is dying during
877 initrd= [BOOT] Specify the location of the initial ramdisk
879 inport.irq= [HW] Inport (ATI XL and Microsoft) busmouse driver
897 intel_iommu= [DMAR] Intel IOMMU driver (DMAR) option
899 Disable intel iommu driver.
900 igfx_off [Default Off]
901 By default, gfx is mapped as normal device. If a gfx
902 device has a dedicated DMAR unit, the DMAR unit is
903 bypassed by not enabling DMAR with this option. In
904 this case, gfx device will use physical address for
907 With this option iommu will not optimize to look
908 for io virtual address below 32 bit forcing dual
909 address cycle on pci bus for cards supporting greater
910 than 32 bit addressing. The default is to look
911 for translation below 32 bit and if not available
912 then look in the higher range.
914 With this option on every unmap_single operation will
915 result in a hardware IOTLB flush operation as opposed
916 to batching them for performance.
918 io_delay= [X86-32,X86-64] I/O delay method
920 Standard port 0x80 based delay
922 Alternate port 0xed based delay (needed on some systems)
924 Simple two microseconds delay
928 io7= [HW] IO7 for Marvel based alpha systems
929 See comment before marvel_specify_io7 in
930 arch/alpha/kernel/core_marvel.c.
933 See Documentation/filesystems/nfsroot.txt.
935 ip2= [HW] Set IO/IRQ pairs for up to 4 IntelliPort boards
936 See comment before ip2_setup() in
937 drivers/char/ip2/ip2base.c.
939 ips= [HW,SCSI] Adaptec / IBM ServeRAID controller
940 See header of drivers/scsi/ips.c.
942 ports= [IP_VS_FTP] IPVS ftp helper module
944 Up to 8 (IP_VS_APP_MAX_PORTS) ports
946 Format: <port>,<port>....
949 When an interrupt is not handled search all handlers
950 for it. Intended to get systems with badly broken
954 When an interrupt is not handled search all handlers
955 for it. Also check all handlers each timer
956 interrupt. Intended to get systems with badly broken
960 Format: <RDP>,<reset>,<pci_scan>,<verbosity>
962 isolcpus= [KNL,SMP] Isolate CPUs from the general scheduler.
964 <cpu number>,...,<cpu number>
966 <cpu number>-<cpu number> (must be a positive range in ascending order)
968 <cpu number>,...,<cpu number>-<cpu number>
969 This option can be used to specify one or more CPUs
970 to isolate from the general SMP balancing and scheduling
971 algorithms. The only way to move a process onto or off
972 an "isolated" CPU is via the CPU affinity syscalls.
973 <cpu number> begins at 0 and the maximum value is
974 "number of CPUs in system - 1".
976 This option is the preferred way to isolate CPUs. The
977 alternative -- manually setting the CPU mask of all
978 tasks in the system -- can cause problems and
979 suboptimal load balancer performance.
983 js= [HW,JOY] Analog joystick
984 See Documentation/input/joystick.txt.
986 kernelcore=nn[KMG] [KNL,X86-32,IA-64,PPC,X86-64] This parameter
987 specifies the amount of memory usable by the kernel
988 for non-movable allocations. The requested amount is
989 spread evenly throughout all nodes in the system. The
990 remaining memory in each node is used for Movable
991 pages. In the event, a node is too small to have both
992 kernelcore and Movable pages, kernelcore pages will
993 take priority and other nodes will have a larger number
994 of kernelcore pages. The Movable zone is used for the
995 allocation of pages that may be reclaimed or moved
996 by the page migration subsystem. This means that
997 HugeTLB pages may not be allocated from this zone.
998 Note that allocations like PTEs-from-HighMem still
999 use the HighMem zone if it exists, and the Normal
1000 zone if it does not.
1002 movablecore=nn[KMG] [KNL,X86-32,IA-64,PPC,X86-64] This parameter
1003 is similar to kernelcore except it specifies the
1004 amount of memory used for migratable allocations.
1005 If both kernelcore and movablecore is specified,
1006 then kernelcore will be at *least* the specified
1007 value but may be more. If movablecore on its own
1008 is specified, the administrator must be careful
1009 that the amount of memory usable for all allocations
1014 kstack=N [X86-32,X86-64] Print N words from the kernel stack
1017 kgdboc= [HW] kgdb over consoles.
1018 Requires a tty driver that supports console polling.
1019 (only serial suported for now)
1020 Format: <serial_device>[,baud]
1026 lapic [X86-32,APIC] Enable the local APIC even if BIOS
1029 lapic_timer_c2_ok [X86-32,x86-64,APIC] trust the local apic timer in
1032 libata.dma= [LIBATA] DMA control
1033 libata.dma=0 Disable all PATA and SATA DMA
1034 libata.dma=1 PATA and SATA Disk DMA only
1035 libata.dma=2 ATAPI (CDROM) DMA only
1036 libata.dma=4 Compact Flash DMA only
1037 Combinations also work, so libata.dma=3 enables DMA
1038 for disks and CDROMs, but not CFs.
1040 libata.noacpi [LIBATA] Disables use of ACPI in libata suspend/resume
1044 libata.force= [LIBATA] Force configurations. The format is comma
1045 separated list of "[ID:]VAL" where ID is
1046 PORT[:DEVICE]. PORT and DEVICE are decimal numbers
1047 matching port, link or device. Basically, it matches
1048 the ATA ID string printed on console by libata. If
1049 the whole ID part is omitted, the last PORT and DEVICE
1050 values are used. If ID hasn't been specified yet, the
1051 configuration applies to all ports, links and devices.
1053 If only DEVICE is omitted, the parameter applies to
1054 the port and all links and devices behind it. DEVICE
1055 number of 0 either selects the first device or the
1056 first fan-out link behind PMP device. It does not
1057 select the host link. DEVICE number of 15 selects the
1058 host link and device attached to it.
1060 The VAL specifies the configuration to force. As long
1061 as there's no ambiguity shortcut notation is allowed.
1062 For example, both 1.5 and 1.5G would work for 1.5Gbps.
1063 The following configurations can be forced.
1065 * Cable type: 40c, 80c, short40c, unk, ign or sata.
1066 Any ID with matching PORT is used.
1068 * SATA link speed limit: 1.5Gbps or 3.0Gbps.
1070 * Transfer mode: pio[0-7], mwdma[0-4] and udma[0-7].
1071 udma[/][16,25,33,44,66,100,133] notation is also
1074 * [no]ncq: Turn on or off NCQ.
1076 If there are multiple matching configurations changing
1077 the same attribute, the last one is used.
1079 load_ramdisk= [RAM] List of ramdisks to load from floppy
1080 See Documentation/ramdisk.txt.
1082 lockd.nlm_grace_period=P [NFS] Assign grace period.
1085 lockd.nlm_tcpport=N [NFS] Assign TCP port.
1088 lockd.nlm_timeout=T [NFS] Assign timeout value.
1091 lockd.nlm_udpport=M [NFS] Assign UDP port.
1094 logibm.irq= [HW,MOUSE] Logitech Bus Mouse Driver
1097 loglevel= All Kernel Messages with a loglevel smaller than the
1098 console loglevel will be printed to the console. It can
1099 also be changed with klogd or other programs. The
1100 loglevels are defined as follows:
1102 0 (KERN_EMERG) system is unusable
1103 1 (KERN_ALERT) action must be taken immediately
1104 2 (KERN_CRIT) critical conditions
1105 3 (KERN_ERR) error conditions
1106 4 (KERN_WARNING) warning conditions
1107 5 (KERN_NOTICE) normal but significant condition
1108 6 (KERN_INFO) informational
1109 7 (KERN_DEBUG) debug-level messages
1111 log_buf_len=n Sets the size of the printk ring buffer, in bytes.
1112 Format: { n | nk | nM }
1113 n must be a power of two. The default size
1114 is set in the kernel config file.
1116 logo.nologo [FB] Disables display of the built-in Linux logo.
1117 This may be used to provide more screen space for
1118 kernel log messages and is useful when debugging
1119 kernel boot problems.
1121 lp=0 [LP] Specify parallel ports to use, e.g,
1122 lp=port[,port...] lp=none,parport0 (lp0 not configured, lp1 uses
1123 lp=reset first parallel port). 'lp=0' disables the
1124 lp=auto printer driver. 'lp=reset' (which can be
1125 specified in addition to the ports) causes
1126 attached printers to be reset. Using
1127 lp=port1,port2,... specifies the parallel ports
1128 to associate lp devices with, starting with
1129 lp0. A port specification may be 'none' to skip
1130 that lp device, or a parport name such as
1131 'parport0'. Specifying 'lp=auto' instead of a
1132 port specification list means that device IDs
1133 from each port should be examined, to see if
1134 an IEEE 1284-compliant printer is attached; if
1135 so, the driver will manage that printer.
1136 See also header of drivers/char/lp.c.
1139 Sets loops_per_jiffy to given constant, thus avoiding
1140 time-consuming boot-time autodetection (up to 250 ms per
1141 CPU). 0 enables autodetection (default). To determine
1142 the correct value for your kernel, boot with normal
1143 autodetection and see what value is printed. Note that
1144 on SMP systems the preset will be applied to all CPUs,
1145 which is likely to cause problems if your CPUs need
1146 significantly divergent settings. An incorrect value
1147 will cause delays in the kernel to be wrong, leading to
1148 unpredictable I/O errors and other breakage. Although
1149 unlikely, in the extreme case this might damage your
1153 Format: <io>,<irq>,<dma>
1155 mac5380= [HW,SCSI] Format:
1156 <can_queue>,<cmd_per_lun>,<sg_tablesize>,<hostid>,<use_tags>
1158 machvec= [IA64] Force the use of a particular machine-vector
1159 (machvec) in a generic kernel.
1160 Example: machvec=hpzx1_swiotlb
1162 max_loop= [LOOP] Maximum number of loopback devices that can
1166 maxcpus= [SMP] Maximum number of processors that an SMP kernel
1167 should make use of. maxcpus=n : n >= 0 limits the
1168 kernel to using 'n' processors. n=0 is a special case,
1169 it is equivalent to "nosmp", which also disables
1172 max_addr=[KMG] [KNL,BOOT,ia64] All physical memory greater than or
1173 equal to this physical address is ignored.
1175 max_luns= [SCSI] Maximum number of LUNs to probe.
1176 Should be between 1 and 2^32-1.
1179 [SCSI] Maximum number of LUNs received.
1180 Should be between 1 and 16384.
1184 mce [X86-32] Machine Check Exception
1186 mce=option [X86-64] See Documentation/x86_64/boot-options.txt
1188 md= [HW] RAID subsystems devices and level
1189 See Documentation/md.txt.
1192 Format: <first>,<last>
1193 Specifies range of consoles to be captured by the MDA.
1195 mem=nn[KMG] [KNL,BOOT] Force usage of a specific amount of memory
1196 Amount of memory to be used when the kernel is not able
1197 to see the whole system memory or for test.
1198 [X86-32] Use together with memmap= to avoid physical
1199 address space collisions. Without memmap= PCI devices
1200 could be placed at addresses belonging to unused RAM.
1202 mem=nopentium [BUGS=X86-32] Disable usage of 4MB pages for kernel
1205 memmap=exactmap [KNL,X86-32,X86_64] Enable setting of an exact
1206 E820 memory map, as specified by the user.
1207 Such memmap=exactmap lines can be constructed based on
1208 BIOS output or other requirements. See the memmap=nn@ss
1211 memmap=nn[KMG]@ss[KMG]
1212 [KNL] Force usage of a specific region of memory
1213 Region of memory to be used, from ss to ss+nn.
1215 memmap=nn[KMG]#ss[KMG]
1216 [KNL,ACPI] Mark specific memory as ACPI data.
1217 Region of memory to be used, from ss to ss+nn.
1219 memmap=nn[KMG]$ss[KMG]
1220 [KNL,ACPI] Mark specific memory as reserved.
1221 Region of memory to be used, from ss to ss+nn.
1222 Example: Exclude memory from 0x18690000-0x1869ffff
1223 memmap=64K$0x18690000
1225 memmap=0x10000$0x18690000
1227 memtest= [KNL,X86] Enable memtest
1229 range: 0,4 : pattern number
1230 default : 0 <disable>
1232 meye.*= [HW] Set MotionEye Camera parameters
1233 See Documentation/video4linux/meye.txt.
1235 mfgpt_irq= [IA-32] Specify the IRQ to use for the
1236 Multi-Function General Purpose Timers on AMD Geode
1239 mfgptfix [X86-32] Fix MFGPT timers on AMD Geode platforms when
1240 the BIOS has incorrectly applied a workaround. TinyBIOS
1241 version 0.98 is known to be affected, 0.99 fixes the
1242 problem by letting the user disable the workaround.
1247 [KNL] When CONFIG_DEBUG_MEMORY_INIT is set, this
1248 parameter allows control of the logging verbosity for
1249 the additional memory initialisation checks. A value
1250 of 0 disables mminit logging and a level of 4 will
1251 log everything. Information is printed at KERN_DEBUG
1252 so loglevel=8 may also need to be specified.
1255 [MOUSE] Maximum time between finger touching and
1256 leaving touchpad surface for touch to be considered
1257 a tap and be reported as a left button click (for
1258 touchpads working in absolute mode only).
1260 mousedev.xres= [MOUSE] Horizontal screen resolution, used for devices
1261 reporting absolute coordinates, such as tablets
1262 mousedev.yres= [MOUSE] Vertical screen resolution, used for devices
1263 reporting absolute coordinates, such as tablets
1268 MTD_Partition= [MTD]
1269 Format: <name>,<region-number>,<size>,<offset>
1271 MTD_Region= [MTD] Format:
1272 <name>,<region-number>[,<base>,<size>,<buswidth>,<altbuswidth>]
1275 See drivers/mtd/cmdlinepart.c.
1278 ARM/S3C2412 JIVE boot control
1280 See arch/arm/mach-s3c2412/mach-jive.c
1282 mtouchusb.raw_coordinates=
1283 [HW] Make the MicroTouch USB driver use raw coordinates
1284 ('y', default) or cooked coordinates ('n')
1286 n2= [NET] SDL Inc. RISCom/N2 synchronous serial card
1289 See header of drivers/scsi/NCR_D700.c.
1293 ncr53c400= [HW,SCSI]
1295 ncr53c400a= [HW,SCSI]
1297 ncr53c406a= [HW,SCSI]
1299 ncr53c8xx= [HW,SCSI]
1301 netdev= [NET] Network devices parameters
1302 Format: <irq>,<io>,<mem_start>,<mem_end>,<name>
1303 Note that mem_start is often overloaded to mean
1304 something different and driver-specific.
1305 This usage is only documented in each driver source
1309 [NETFILTER] Enable connection tracking flow accounting
1310 0 to disable accounting
1311 1 to enable accounting
1312 Default value depends on CONFIG_NF_CT_ACCT that is
1313 going to be removed in 2.6.29.
1316 See Documentation/filesystems/nfsroot.txt.
1318 nfsroot= [NFS] nfs root filesystem for disk-less boxes.
1319 See Documentation/filesystems/nfsroot.txt.
1321 nfs.callback_tcpport=
1322 [NFS] set the TCP port on which the NFSv4 callback
1323 channel should listen.
1325 nfs.idmap_cache_timeout=
1326 [NFS] set the maximum lifetime for idmapper cache
1330 [NFS] enable 64-bit inode numbers.
1331 If zero, the NFS client will fake up a 32-bit inode
1332 number for the readdir() and stat() syscalls instead
1333 of returning the full 64-bit number.
1334 The default is to return 64-bit inode numbers.
1336 nmi_debug= [KNL,AVR32] Specify one or more actions to take
1337 when a NMI is triggered.
1338 Format: [state][,regs][,debounce][,die]
1340 nmi_watchdog= [KNL,BUGS=X86-32] Debugging features for SMP kernels
1342 no387 [BUGS=X86-32] Tells the kernel to use the 387 maths
1343 emulation library even if a 387 maths coprocessor
1346 noaliencache [MM, NUMA, SLAB] Disables the allocation of alien
1347 caches in the slab allocator. Saves per-node memory,
1348 but will impact performance.
1352 noapic [SMP,APIC] Tells the kernel to not make use of any
1353 IOAPICs that may be present in the system.
1355 nobats [PPC] Do not use BATs for mapping kernel lowmem
1356 on "Classic" PPC cores.
1360 nodelayacct [KNL] Disable per-task delay accounting
1362 nodisconnect [HW,SCSI,M68K] Disables SCSI disconnects.
1364 noefi [X86-32,X86-64] Disable EFI runtime services support.
1368 noexec [X86-32,X86-64]
1369 On X86-32 available only on PAE configured kernels.
1370 noexec=on: enable non-executable mappings (default)
1371 noexec=off: disable non-executable mappings
1374 This affects only 32-bit executables.
1375 noexec32=on: enable non-executable mappings (default)
1376 read doesn't imply executable mappings
1377 noexec32=off: disable non-executable mappings
1378 read implies executable mappings
1380 nofxsr [BUGS=X86-32] Disables x86 floating point extended
1381 register save and restore. The kernel will only save
1382 legacy floating-point registers on task switch.
1384 noclflush [BUGS=X86] Don't use the CLFLUSH instruction
1388 no-hlt [BUGS=X86-32] Tells the kernel that the hlt
1389 instruction doesn't work correctly and not to
1392 nohalt [IA-64] Tells the kernel not to use the power saving
1393 function PAL_HALT_LIGHT when idle. This increases
1394 power-consumption. On the positive side, it reduces
1395 interrupt wake-up latency, which may improve performance
1396 in certain environments such as networked servers or
1399 nohz= [KNL] Boottime enable/disable dynamic ticks
1400 Valid arguments: on, off
1403 noirqbalance [X86-32,SMP,KNL] Disable kernel irq balancing
1405 noirqdebug [X86-32] Disables the code which attempts to detect and
1406 disable unhandled interrupt sources.
1408 no_timer_check [X86-32,X86_64,APIC] Disables the code which tests for
1409 broken timer IRQ sources.
1411 noisapnp [ISAPNP] Disables ISA PnP code.
1413 noinitrd [RAM] Tells the kernel not to load any configured
1418 nojitter [IA64] Disables jitter checking for ITC timers.
1420 nolapic [X86-32,APIC] Do not enable or use the local APIC.
1422 nolapic_timer [X86-32,APIC] Do not use the local APIC timer.
1424 noltlbs [PPC] Do not use large page/tlb entries for kernel
1425 lowmem mapping on PPC40x.
1427 nomca [IA-64] Disable machine check abort handling
1429 nomce [X86-32] Machine Check Exception
1431 nomfgpt [X86-32] Disable Multi-Function General Purpose
1432 Timer usage (for AMD Geode machines).
1434 noreplace-paravirt [X86-32,PV_OPS] Don't patch paravirt_ops
1436 noreplace-smp [X86-32,SMP] Don't replace SMP instructions
1437 with UP alternatives
1439 noresidual [PPC] Don't use residual data on PReP machines.
1441 noresume [SWSUSP] Disables resume and restores original swap
1444 no-scroll [VGA] Disables scrollback.
1445 This is required for the Braillex ib80-piezo Braille
1446 reader made by F.H. Papenmeier (Germany).
1450 nosep [BUGS=X86-32] Disables x86 SYSENTER/SYSEXIT support.
1452 nosmp [SMP] Tells an SMP kernel to act as a UP kernel,
1453 and disable the IO APIC. legacy for "maxcpus=0".
1455 nosoftlockup [KNL] Disable the soft-lockup detector.
1457 nosync [HW,M68K] Disables sync negotiation for all devices.
1459 notsc [BUGS=X86-32] Disable Time Stamp Counter
1461 nousb [USB] Disable the USB subsystem
1465 nptcg= [IA64] Override max number of concurrent global TLB
1466 purges which is reported from either PAL_VM_SUMMARY or
1469 numa_zonelist_order= [KNL, BOOT] Select zonelist order for NUMA.
1470 one of ['zone', 'node', 'default'] can be specified
1471 This can be set from sysctl after boot.
1472 See Documentation/sysctl/vm.txt for details.
1474 nr_uarts= [SERIAL] maximum number of UARTs to be registered.
1476 olpc_ec_timeout= [OLPC] ms delay when issuing EC commands
1477 Rather than timing out after 20 ms if an EC
1478 command is not properly ACKed, override the length
1479 of the timeout. We have interrupts disabled while
1480 waiting for the ACK, so if this is set too high
1481 interrupts *may* be lost!
1486 oprofile.timer= [HW]
1487 Use timer interrupt instead of performance counters
1489 osst= [HW,SCSI] SCSI Tape Driver
1490 Format: <buffer_size>,<write_threshold>
1491 See also Documentation/scsi/st.txt.
1493 panic= [KNL] Kernel behaviour on panic
1496 parkbd.port= [HW] Parallel port number the keyboard adapter is
1497 connected to, default is 0.
1499 parkbd.mode= [HW] Parallel port keyboard adapter mode of operation,
1500 0 for XT, 1 for AT (default is AT).
1503 parport= [HW,PPT] Specify parallel ports. 0 disables.
1504 Format: { 0 | auto | 0xBBB[,IRQ[,DMA]] }
1505 Use 'auto' to force the driver to use any
1506 IRQ/DMA settings detected (the default is to
1507 ignore detected IRQ/DMA settings because of
1508 possible conflicts). You can specify the base
1509 address, IRQ, and DMA settings; IRQ and DMA
1510 should be numbers, or 'auto' (for using detected
1511 settings on that particular port), or 'nofifo'
1512 (to avoid using a FIFO even if it is detected).
1513 Parallel ports are assigned in the order they
1514 are specified on the command line, starting
1517 parport_init_mode= [HW,PPT]
1518 Configure VIA parallel port to operate in
1519 a specific mode. This is necessary on Pegasos
1520 computer where firmware has no options for setting
1521 up parallel port mode and sets it to spp.
1522 Currently this function knows 686a and 8231 chips.
1523 Format: [spp|ps2|epp|ecp|ecpepp]
1525 pas2= [HW,OSS] Format:
1526 <io>,<irq>,<dma>,<dma16>,<sb_io>,<sb_irq>,<sb_dma>,<sb_dma16>
1529 See header of drivers/scsi/pas16.c.
1532 Halt all CPUs after the first oops has been printed for
1533 the specified number of seconds. This is to be used if
1534 your oopses keep scrolling off the screen.
1539 See header of drivers/block/paride/pcd.c.
1540 See also Documentation/paride.txt.
1542 pci=option[,option...] [PCI] various PCI subsystem options:
1543 off [X86-32] don't probe for the PCI bus
1544 bios [X86-32] force use of PCI BIOS, don't access
1545 the hardware directly. Use this if your machine
1546 has a non-standard PCI host bridge.
1547 nobios [X86-32] disallow use of PCI BIOS, only direct
1548 hardware access methods are allowed. Use this
1549 if you experience crashes upon bootup and you
1550 suspect they are caused by the BIOS.
1551 conf1 [X86-32] Force use of PCI Configuration
1553 conf2 [X86-32] Force use of PCI Configuration
1555 noaer [PCIE] If the PCIEAER kernel config parameter is
1556 enabled, this kernel boot option can be used to
1557 disable the use of PCIE advanced error reporting.
1558 nodomains [PCI] Disable support for multiple PCI
1559 root domains (aka PCI segments, in ACPI-speak).
1560 nommconf [X86-32,X86_64] Disable use of MMCONFIG for PCI
1562 nomsi [MSI] If the PCI_MSI kernel config parameter is
1563 enabled, this kernel boot option can be used to
1564 disable the use of MSI interrupts system-wide.
1565 biosirq [X86-32] Use PCI BIOS calls to get the interrupt
1566 routing table. These calls are known to be buggy
1567 on several machines and they hang the machine
1568 when used, but on other computers it's the only
1569 way to get the interrupt routing table. Try
1570 this option if the kernel is unable to allocate
1571 IRQs or discover secondary PCI buses on your
1573 rom [X86-32] Assign address space to expansion ROMs.
1574 Use with caution as certain devices share
1575 address decoders between ROMs and other
1577 norom [X86-32,X86_64] Do not assign address space to
1578 expansion ROMs that do not already have
1579 BIOS assigned address ranges.
1580 irqmask=0xMMMM [X86-32] Set a bit mask of IRQs allowed to be
1581 assigned automatically to PCI devices. You can
1582 make the kernel exclude IRQs of your ISA cards
1584 pirqaddr=0xAAAAA [X86-32] Specify the physical address
1585 of the PIRQ table (normally generated
1586 by the BIOS) if it is outside the
1587 F0000h-100000h range.
1588 lastbus=N [X86-32] Scan all buses thru bus #N. Can be
1589 useful if the kernel is unable to find your
1590 secondary buses and you want to tell it
1591 explicitly which ones they are.
1592 assign-busses [X86-32] Always assign all PCI bus
1593 numbers ourselves, overriding
1594 whatever the firmware may have done.
1595 usepirqmask [X86-32] Honor the possible IRQ mask stored
1596 in the BIOS $PIR table. This is needed on
1597 some systems with broken BIOSes, notably
1598 some HP Pavilion N5400 and Omnibook XE3
1599 notebooks. This will have no effect if ACPI
1600 IRQ routing is enabled.
1601 noacpi [X86-32] Do not use ACPI for IRQ routing
1602 or for PCI scanning.
1603 use_crs [X86-32] Use _CRS for PCI resource
1605 routeirq Do IRQ routing for all PCI devices.
1606 This is normally done in pci_enable_device(),
1607 so this option is a temporary workaround
1608 for broken drivers that don't call it.
1609 skip_isa_align [X86] do not align io start addr, so can
1610 handle more pci cards
1611 firmware [ARM] Do not re-enumerate the bus but instead
1612 just use the configuration from the
1613 bootloader. This is currently used on
1614 IXP2000 systems where the bus has to be
1615 configured a certain way for adjunct CPUs.
1616 noearly [X86] Don't do any early type 1 scanning.
1617 This might help on some broken boards which
1618 machine check when some devices' config space
1619 is read. But various workarounds are disabled
1620 and some IOMMU drivers will not work.
1621 bfsort Sort PCI devices into breadth-first order.
1622 This sorting is done to get a device
1623 order compatible with older (<= 2.4) kernels.
1624 nobfsort Don't sort PCI devices into breadth-first order.
1625 cbiosize=nn[KMG] The fixed amount of bus space which is
1626 reserved for the CardBus bridge's IO window.
1627 The default value is 256 bytes.
1628 cbmemsize=nn[KMG] The fixed amount of bus space which is
1629 reserved for the CardBus bridge's memory
1630 window. The default value is 64 megabytes.
1632 pcmv= [HW,PCMCIA] BadgePAD 4
1635 See Documentation/paride.txt.
1637 pdcchassis= [PARISC,HW] Disable/Enable PDC Chassis Status codes at
1640 See arch/parisc/kernel/pdc_chassis.c
1643 See Documentation/paride.txt.
1646 See Documentation/paride.txt.
1648 pirq= [SMP,APIC] Manual mp-table setup
1649 See Documentation/i386/IO-APIC.txt.
1651 plip= [PPT,NET] Parallel port network link
1652 Format: { parport<nr> | timid | 0 }
1653 See also Documentation/parport.txt.
1655 pmtmr= [X86] Manual setup of pmtmr I/O Port.
1656 Override pmtimer IOPort with a hex value.
1663 { on | off | curr | res | no-curr | no-res }
1666 [ISAPNP] Exclude IRQs for the autoconfiguration
1669 [ISAPNP] Exclude DMAs for the autoconfiguration
1671 pnp_reserve_io= [ISAPNP] Exclude I/O ports for the autoconfiguration
1672 Ranges are in pairs (I/O port base and size).
1675 [ISAPNP] Exclude memory regions for the
1677 Ranges are in pairs (memory base and size).
1679 print-fatal-signals=
1680 [KNL] debug: print fatal signals
1681 print-fatal-signals=1: print segfault info to
1685 printk.time= Show timing data prefixed to each printk message line
1686 Format: <bool> (1/Y/y=enable, 0/N/n=disable)
1688 profile= [KNL] Enable kernel profiling via /proc/profile
1689 Format: [schedule,]<number>
1690 Param: "schedule" - profile schedule points.
1691 Param: <number> - step/bucket size as a power of 2 for
1692 statistical time based profiling.
1693 Param: "sleep" - profile D-state sleeping (millisecs).
1694 Requires CONFIG_SCHEDSTATS
1695 Param: "kvm" - profile VM exits.
1697 processor.max_cstate= [HW,ACPI]
1698 Limit processor to maximum C-state
1699 max_cstate=9 overrides any DMI blacklist limit.
1701 processor.nocst [HW,ACPI]
1702 Ignore the _CST method to determine C-states,
1703 instead using the legacy FADT method
1705 prompt_ramdisk= [RAM] List of RAM disks to prompt for floppy disk
1707 See Documentation/ramdisk.txt.
1709 psmouse.proto= [HW,MOUSE] Highest PS2 mouse protocol extension to
1710 probe for; one of (bare|imps|exps|lifebook|any).
1711 psmouse.rate= [HW,MOUSE] Set desired mouse report rate, in reports
1713 psmouse.resetafter= [HW,MOUSE]
1714 Try to reset the device after so many bad packets
1717 [HW,MOUSE] Set desired mouse resolution, in dpi.
1718 psmouse.smartscroll=
1719 [HW,MOUSE] Controls Logitech smartscroll autorepeat.
1720 0 = disabled, 1 = enabled (default).
1722 pss= [HW,OSS] Personal Sound System (ECHO ESC614)
1724 <io>,<mss_io>,<mss_irq>,<mss_dma>,<mpu_io>,<mpu_irq>
1727 See Documentation/paride.txt.
1730 [KNL] Number of legacy pty's. Overwrites compiled-in
1733 quiet [KNL] Disable most log messages
1738 See Documentation/md.txt.
1740 ramdisk_blocksize= [RAM]
1741 See Documentation/ramdisk.txt.
1743 ramdisk_size= [RAM] Sizes of RAM disks in kilobytes
1744 See Documentation/ramdisk.txt.
1746 rcupdate.blimit= [KNL,BOOT]
1747 Set maximum number of finished RCU callbacks to process
1750 rcupdate.qhimark= [KNL,BOOT]
1751 Set threshold of queued
1752 RCU callbacks over which batch limiting is disabled.
1754 rcupdate.qlowmark= [KNL,BOOT]
1755 Set threshold of queued RCU callbacks below which
1756 batch limiting is re-enabled.
1760 Run specified binary instead of /init from the ramdisk,
1761 used for early userspace startup. See initrd.
1763 reboot= [BUGS=X86-32,BUGS=ARM,BUGS=IA-64] Rebooting mode
1764 Format: <reboot_mode>[,<reboot_mode2>[,...]]
1765 See arch/*/kernel/reboot.c or arch/*/kernel/process.c
1768 [KNL, SMP] Set scheduler's default relax_domain_level.
1769 See Documentation/cpusets.txt.
1771 reserve= [KNL,BUGS] Force the kernel to ignore some iomem area
1773 reservetop= [X86-32]
1775 Reserves a hole at the top of the kernel virtual
1778 reset_devices [KNL] Force drivers to reset the underlying device
1779 during initialization.
1782 Specify the partition device for software suspend
1784 resume_offset= [SWSUSP]
1785 Specify the offset from the beginning of the partition
1786 given by "resume=" at which the swap header is located,
1787 in <PAGE_SIZE> units (needed only for swap files).
1788 See Documentation/power/swsusp-and-swap-files.txt
1790 retain_initrd [RAM] Keep initrd memory after extraction
1792 rhash_entries= [KNL,NET]
1793 Set number of hash buckets for route cache
1795 riscom8= [HW,SERIAL]
1796 Format: <io_board1>[,<io_board2>[,...<io_boardN>]]
1798 ro [KNL] Mount root device read-only on boot
1800 root= [KNL] Root filesystem
1802 rootdelay= [KNL] Delay (in seconds) to pause before attempting to
1803 mount the root filesystem
1805 rootflags= [KNL] Set root filesystem mount option string
1807 rootfstype= [KNL] Set root filesystem type
1809 rootwait [KNL] Wait (indefinitely) for root device to show up.
1810 Useful for devices that are detected asynchronously
1811 (e.g. USB and MMC devices).
1813 root_plug.vendor_id=
1814 [ROOTPLUG] Override the default vendor ID
1816 root_plug.product_id=
1817 [ROOTPLUG] Override the default product ID
1820 [ROOTPLUG] Enable debugging output
1822 rw [KNL] Mount root device read-write on boot
1824 S [KNL] Run init in single mode
1827 See drivers/net/irda/sa1100_ir.c.
1829 sbni= [NET] Granch SBNI12 leased line adapter
1831 sc1200wdt= [HW,WDT] SC1200 WDT (watchdog) driver
1832 Format: <io>[,<timeout>[,<isapnp>]]
1834 scsi_debug_*= [SCSI]
1835 See drivers/scsi/scsi_debug.c.
1837 scsi_default_dev_flags=
1838 [SCSI] SCSI default device flags
1841 scsi_dev_flags= [SCSI] Black/white list entry for vendor and model
1842 Format: <vendor>:<model>:<flags>
1843 (flags are integer value)
1845 scsi_logging_level= [SCSI] a bit mask of logging levels
1846 See drivers/scsi/scsi_logging.h for bits. Also
1847 settable via sysctl at dev.scsi.logging_level
1848 (/proc/sys/dev/scsi/logging_level).
1849 There is also a nice 'scsi_logging_level' script in the
1850 S390-tools package, available for download at
1851 http://www-128.ibm.com/developerworks/linux/linux390/s390-tools-1.5.4.html
1853 scsi_mod.scan= [SCSI] sync (default) scans SCSI busses as they are
1854 discovered. async scans them in kernel threads,
1855 allowing boot to proceed. none ignores them, expecting
1856 user space to do the scan.
1858 selinux [SELINUX] Disable or enable SELinux at boot time.
1859 Format: { "0" | "1" }
1860 See security/selinux/Kconfig help text.
1863 Default value is set via kernel config option.
1864 If enabled at boot time, /selinux/disable can be used
1865 later to disable prior to initial policy load.
1867 selinux_compat_net =
1868 [SELINUX] Set initial selinux_compat_net flag value.
1869 Format: { "0" | "1" }
1870 0 -- use new secmark-based packet controls
1871 1 -- use legacy packet controls
1872 Default value is 0 (preferred).
1873 Value can be changed at runtime via
1874 /selinux/compat_net.
1876 serialnumber [BUGS=X86-32]
1879 Maximal number of shapers.
1882 See header of drivers/scsi/sim710.c.
1889 slub_debug[=options[,slabs]] [MM, SLUB]
1890 Enabling slub_debug allows one to determine the
1891 culprit if slab objects become corrupted. Enabling
1892 slub_debug can create guard zones around objects and
1893 may poison objects when not in use. Also tracks the
1894 last alloc / free. For more information see
1895 Documentation/vm/slub.txt.
1897 slub_max_order= [MM, SLUB]
1898 Determines the maximum allowed order for slabs.
1899 A high setting may cause OOMs due to memory
1900 fragmentation. For more information see
1901 Documentation/vm/slub.txt.
1903 slub_min_objects= [MM, SLUB]
1904 The minimum number of objects per slab. SLUB will
1905 increase the slab order up to slub_max_order to
1906 generate a sufficiently large slab able to contain
1907 the number of objects indicated. The higher the number
1908 of objects the smaller the overhead of tracking slabs
1909 and the less frequently locks need to be acquired.
1910 For more information see Documentation/vm/slub.txt.
1912 slub_min_order= [MM, SLUB]
1913 Determines the mininum page order for slabs. Must be
1914 lower than slub_max_order.
1915 For more information see Documentation/vm/slub.txt.
1917 slub_nomerge [MM, SLUB]
1918 Disable merging of slabs with similar size. May be
1919 necessary if there is some reason to distinguish
1920 allocs to different slabs. Debug options disable
1921 merging on their own.
1922 For more information see Documentation/vm/slub.txt.
1925 Format: <io1>[,<io2>[,...,<io8>]]
1927 smp-alt-once [X86-32,SMP] On a hotplug CPU system, only
1928 attempt to substitute SMP alternatives once at boot.
1930 smsc-ircc2.nopnp [HW] Don't use PNP to discover SMC devices
1931 smsc-ircc2.ircc_cfg= [HW] Device configuration I/O port
1932 smsc-ircc2.ircc_sir= [HW] SIR base I/O port
1933 smsc-ircc2.ircc_fir= [HW] FIR base I/O port
1934 smsc-ircc2.ircc_irq= [HW] IRQ line
1935 smsc-ircc2.ircc_dma= [HW] DMA channel
1936 smsc-ircc2.ircc_transceiver= [HW] Transceiver type:
1937 0: Toshiba Satellite 1800 (GP data pin select)
1938 1: Fast pin select (default)
1941 snd-ad1816a= [HW,ALSA]
1943 snd-ad1848= [HW,ALSA]
1945 snd-ali5451= [HW,ALSA]
1947 snd-als100= [HW,ALSA]
1949 snd-als4000= [HW,ALSA]
1951 snd-azt2320= [HW,ALSA]
1953 snd-cmi8330= [HW,ALSA]
1955 snd-cmipci= [HW,ALSA]
1957 snd-cs4231= [HW,ALSA]
1959 snd-cs4232= [HW,ALSA]
1961 snd-cs4236= [HW,ALSA]
1963 snd-cs4281= [HW,ALSA]
1965 snd-cs46xx= [HW,ALSA]
1967 snd-dt019x= [HW,ALSA]
1969 snd-dummy= [HW,ALSA]
1971 snd-emu10k1= [HW,ALSA]
1973 snd-ens1370= [HW,ALSA]
1975 snd-ens1371= [HW,ALSA]
1977 snd-es968= [HW,ALSA]
1979 snd-es1688= [HW,ALSA]
1981 snd-es18xx= [HW,ALSA]
1983 snd-es1938= [HW,ALSA]
1985 snd-es1968= [HW,ALSA]
1987 snd-fm801= [HW,ALSA]
1989 snd-gusclassic= [HW,ALSA]
1991 snd-gusextreme= [HW,ALSA]
1993 snd-gusmax= [HW,ALSA]
1997 snd-ice1712= [HW,ALSA]
1999 snd-intel8x0= [HW,ALSA]
2001 snd-interwave= [HW,ALSA]
2006 snd-korg1212= [HW,ALSA]
2008 snd-maestro3= [HW,ALSA]
2010 snd-mpu401= [HW,ALSA]
2012 snd-mtpav= [HW,ALSA]
2014 snd-nm256= [HW,ALSA]
2016 snd-opl3sa2= [HW,ALSA]
2024 snd-opti93x= [HW,ALSA]
2028 snd-rme32= [HW,ALSA]
2030 snd-rme96= [HW,ALSA]
2032 snd-rme9652= [HW,ALSA]
2038 snd-sbawe= [HW,ALSA]
2040 snd-serial= [HW,ALSA]
2042 snd-sgalaxy= [HW,ALSA]
2044 snd-sonicvibes= [HW,ALSA]
2049 snd-sun-cs4231= [HW,ALSA]
2051 snd-trident= [HW,ALSA]
2053 snd-usb-audio= [HW,ALSA,USB]
2055 snd-via82xx= [HW,ALSA]
2057 snd-virmidi= [HW,ALSA]
2059 snd-wavefront= [HW,ALSA]
2061 snd-ymfpci= [HW,ALSA]
2064 [KNL] Should the soft-lockup detector generate panics.
2066 sonypi.*= [HW] Sony Programmable I/O Control Device driver
2067 See Documentation/sonypi.txt
2069 specialix= [HW,SERIAL] Specialix multi-serial port adapter
2070 See Documentation/specialix.txt.
2072 spia_io_base= [HW,MTD]
2078 Format: <io>,<irq>,<dma>,<mpu_io>,<mpu_irq>
2080 st= [HW,SCSI] SCSI tape parameters (buffers, etc.)
2081 See Documentation/scsi/st.txt.
2085 Set the STI (builtin display/keyboard on the HP-PARISC
2086 machines) console (graphic card) which should be used
2087 as the initial boot-console.
2088 See also comment in drivers/video/console/sticore.c.
2091 See comment in drivers/video/console/sticore.c.
2094 Format: bpp:<bpp1>[:<bpp2>[:<bpp3>...]]
2098 Control how the NFS server code allocates CPUs to
2099 service thread pools. Depending on how many NICs
2100 you have and where their interrupts are bound, this
2101 option will affect which CPUs will do NFS serving.
2102 Note: this parameter cannot be changed while the
2103 NFS server is running.
2105 auto the server chooses an appropriate mode
2106 automatically using heuristics
2107 global a single global pool contains all CPUs
2108 percpu one pool for each CPU
2109 pernode one pool for each NUMA node (equivalent
2110 to global on non-NUMA machines)
2112 swiotlb= [IA-64] Number of I/O TLB slabs
2116 sym53c416= [HW,SCSI]
2117 See header of drivers/scsi/sym53c416.c.
2119 sysrq_always_enabled
2121 Ignore sysrq setting - this boot parameter will
2122 neutralize any effect of /proc/sys/kernel/sysrq.
2123 Useful for debugging.
2126 See header of drivers/scsi/t128.c.
2130 test_suspend= [SUSPEND]
2131 Specify "mem" (for Suspend-to-RAM) or "standby" (for
2132 standby suspend) as the system sleep state to briefly
2133 enter during system startup. The system is woken from
2134 this state using a wakeup-capable RTC alarm.
2136 thash_entries= [KNL,NET]
2137 Set number of hash buckets for TCP connection
2139 thermal.act= [HW,ACPI]
2140 -1: disable all active trip points in all thermal zones
2141 <degrees C>: override all lowest active trip points
2143 thermal.crt= [HW,ACPI]
2144 -1: disable all critical trip points in all thermal zones
2145 <degrees C>: lower all critical trip points
2147 thermal.nocrt= [HW,ACPI]
2148 Set to disable actions on ACPI thermal zone
2149 critical and hot trip points.
2151 thermal.off= [HW,ACPI]
2152 1: disable ACPI thermal control
2154 thermal.psv= [HW,ACPI]
2155 -1: disable all passive trip points
2156 <degrees C>: override all passive trip points to this value
2158 thermal.tzp= [HW,ACPI]
2159 Specify global default ACPI thermal zone polling rate
2160 <deci-seconds>: poll all this frequency
2161 0: no polling (default)
2164 See comment before function dc390_setup() in
2165 drivers/scsi/tmscsim.c.
2169 trix= [HW,OSS] MediaTrix AudioTrix Pro
2171 <io>,<irq>,<dma>,<dma2>,<sb_io>,<sb_irq>,<sb_dma>,<mpu_io>,<mpu_irq>
2173 turbografx.map[2|3]= [HW,JOY]
2174 TurboGraFX parallel port interface
2176 <port#>,<js1>,<js2>,<js3>,<js4>,<js5>,<js6>,<js7>
2177 See also Documentation/input/joystick-parport.txt
2179 u14-34f= [HW,SCSI] UltraStor 14F/34F SCSI host adapter
2180 See header of drivers/scsi/u14-34f.c.
2189 [USB] Ignore overcurrent events (default N).
2190 Some badly-designed motherboards generate lots of
2191 bogus events, for ports that aren't wired to
2192 anything. Set this parameter to avoid log spamming.
2193 Note that genuine overcurrent events won't be
2198 Set unknown_nmi_panic=1 early on boot.
2200 usbcore.autosuspend=
2201 [USB] The autosuspend time delay (in seconds) used
2202 for newly-detected USB devices (default 2). This
2203 is the time required before an idle device will be
2204 autosuspended. Devices for which the delay is set
2205 to a negative value won't be autosuspended at all.
2208 [USBHID] The interval which mice are to be polled at.
2210 add_efi_memmap [EFI; x86-32,X86-64] Include EFI memory map in
2211 kernel's map of available physical RAM.
2213 vdso= [X86-32,SH,x86-64]
2214 vdso=2: enable compat VDSO (default with COMPAT_VDSO)
2215 vdso=1: enable VDSO (default)
2216 vdso=0: disable VDSO mapping
2218 vdso32= [X86-32,X86-64]
2219 vdso32=2: enable compat VDSO (default with COMPAT_VDSO)
2220 vdso32=1: enable 32-bit VDSO (default)
2221 vdso32=0: disable 32-bit VDSO mapping
2224 vector=percpu: enable percpu vector domain
2226 video= [FB] Frame buffer configuration
2227 See Documentation/fb/modedb.txt.
2229 vga= [BOOT,X86-32] Select a particular video mode
2230 See Documentation/i386/boot.txt and
2231 Documentation/svga.txt.
2232 Use vga=ask for menu.
2233 This is actually a boot loader parameter; the value is
2234 passed to the kernel using a special protocol.
2236 vmalloc=nn[KMG] [KNL,BOOT] Forces the vmalloc area to have an exact
2237 size of <nn>. This can be used to increase the
2238 minimum size (128MB on x86). It can also be used to
2239 decrease the size and leave more room for directly
2242 vmhalt= [KNL,S390] Perform z/VM CP command after system halt.
2245 vmpanic= [KNL,S390] Perform z/VM CP command after kernel panic.
2248 vmpoff= [KNL,S390] Perform z/VM CP command after power off.
2251 waveartist= [HW,OSS]
2252 Format: <io>,<irq>,<dma>,<dma2>
2255 See header of drivers/scsi/wd33c93.c.
2258 See header of drivers/scsi/wd7000.c.
2261 See Documentation/watchdog/wdt.txt.
2263 xd= [HW,XT] Original XT pre-IDE (RLL encoded) disks.
2264 xd_geo= See header of drivers/block/xd.c.
2266 xirc2ps_cs= [NET,PCMCIA]
2268 <irq>,<irq_mask>,<io>,<full_duplex>,<do_sound>,<lockup_hack>[,<irq2>[,<irq3>[,<irq4>]]]
2270 norandmaps Don't use address space randomization
2271 Equivalent to echo 0 > /proc/sys/kernel/randomize_va_space
2273 ______________________________________________________________________
2277 Add documentation for ALSA options.
2278 Add more DRM drivers.