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 Hyphens (dashes) and underscores are equivalent in parameter names, so
21 log_buf_len=1M print-fatal-signals=1
22 can also be entered as
23 log-buf-len=1M print_fatal_signals=1
26 This document may not be entirely up to date and comprehensive. The command
27 "modinfo -p ${modulename}" shows a current list of all parameters of a loadable
28 module. Loadable modules, after being loaded into the running kernel, also
29 reveal their parameters in /sys/module/${modulename}/parameters/. Some of these
30 parameters may be changed at runtime by the command
31 "echo -n ${value} > /sys/module/${modulename}/parameters/${parm}".
33 The parameters listed below are only valid if certain kernel build options were
34 enabled and if respective hardware is present. The text in square brackets at
35 the beginning of each description states the restrictions within which a
36 parameter is applicable:
38 ACPI ACPI support is enabled.
39 AGP AGP (Accelerated Graphics Port) is enabled.
40 ALSA ALSA sound support is enabled.
41 APIC APIC support is enabled.
42 APM Advanced Power Management support is enabled.
43 AVR32 AVR32 architecture is enabled.
44 AX25 Appropriate AX.25 support is enabled.
45 BLACKFIN Blackfin architecture is enabled.
46 DRM Direct Rendering Management support is enabled.
47 EDD BIOS Enhanced Disk Drive Services (EDD) is enabled
48 EFI EFI Partitioning (GPT) is enabled
49 EIDE EIDE/ATAPI support is enabled.
50 FB The frame buffer device is enabled.
51 GCOV GCOV profiling is enabled.
52 HW Appropriate hardware is enabled.
53 IA-64 IA-64 architecture is enabled.
54 IMA Integrity measurement architecture is enabled.
55 IOSCHED More than one I/O scheduler is enabled.
56 IP_PNP IP DHCP, BOOTP, or RARP is enabled.
57 IPV6 IPv6 support is enabled.
58 ISAPNP ISA PnP code is enabled.
59 ISDN Appropriate ISDN support is enabled.
60 JOY Appropriate joystick support is enabled.
61 KVM Kernel Virtual Machine support is enabled.
62 LIBATA Libata driver is enabled
63 LP Printer support is enabled.
64 LOOP Loopback device support is enabled.
65 M68k M68k architecture is enabled.
66 These options have more detailed description inside of
67 Documentation/m68k/kernel-options.txt.
68 MCA MCA bus support is enabled.
69 MDA MDA console support is enabled.
70 MOUSE Appropriate mouse support is enabled.
71 MSI Message Signaled Interrupts (PCI).
72 MTD MTD (Memory Technology Device) support is enabled.
73 NET Appropriate network support is enabled.
74 NUMA NUMA support is enabled.
75 GENERIC_TIME The generic timeofday code is enabled.
76 NFS Appropriate NFS support is enabled.
77 OSS OSS sound support is enabled.
78 PV_OPS A paravirtualized kernel is enabled.
79 PARIDE The ParIDE (parallel port IDE) subsystem is enabled.
80 PARISC The PA-RISC architecture is enabled.
81 PCI PCI bus support is enabled.
82 PCIE PCI Express support is enabled.
83 PCMCIA The PCMCIA subsystem is enabled.
84 PNP Plug & Play support is enabled.
85 PPC PowerPC architecture is enabled.
86 PPT Parallel port support is enabled.
87 PS2 Appropriate PS/2 support is enabled.
88 RAM RAM disk support is enabled.
89 S390 S390 architecture is enabled.
90 SCSI Appropriate SCSI support is enabled.
91 A lot of drivers has their options described inside of
93 SECURITY Different security models are enabled.
94 SELINUX SELinux support is enabled.
95 SERIAL Serial support is enabled.
96 SH SuperH architecture is enabled.
97 SMP The kernel is an SMP kernel.
98 SPARC Sparc architecture is enabled.
99 SWSUSP Software suspend (hibernation) is enabled.
100 SUSPEND System suspend states are enabled.
101 FTRACE Function tracing enabled.
102 TS Appropriate touchscreen support is enabled.
103 UMS USB Mass Storage support is enabled.
104 USB USB support is enabled.
105 USBHID USB Human Interface Device support is enabled.
106 V4L Video For Linux support is enabled.
107 VGA The VGA console has been enabled.
108 VT Virtual terminal support is enabled.
109 WDT Watchdog support is enabled.
110 XT IBM PC/XT MFM hard disk support is enabled.
111 X86-32 X86-32, aka i386 architecture is enabled.
112 X86-64 X86-64 architecture is enabled.
113 More X86-64 boot options can be found in
114 Documentation/x86/x86_64/boot-options.txt .
115 X86 Either 32bit or 64bit x86 (same as X86-32+X86-64)
117 In addition, the following text indicates that the option:
119 BUGS= Relates to possible processor bugs on the said processor.
120 KNL Is a kernel start-up parameter.
121 BOOT Is a boot loader parameter.
123 Parameters denoted with BOOT are actually interpreted by the boot
124 loader, and have no meaning to the kernel directly.
125 Do not modify the syntax of boot loader parameters without extreme
126 need or coordination with <Documentation/x86/boot.txt>.
128 There are also arch-specific kernel-parameters not documented here.
129 See for example <Documentation/x86/x86_64/boot-options.txt>.
131 Note that ALL kernel parameters listed below are CASE SENSITIVE, and that
132 a trailing = on the name of any parameter states that that parameter will
133 be entered as an environment variable, whereas its absence indicates that
134 it will appear as a kernel argument readable via /proc/cmdline by programs
135 running once the system is up.
137 The number of kernel parameters is not limited, but the length of the
138 complete command line (parameters including spaces etc.) is limited to
139 a fixed number of characters. This limit depends on the architecture
140 and is between 256 and 4096 characters. It is defined in the file
141 ./include/asm/setup.h as COMMAND_LINE_SIZE.
145 Advanced Configuration and Power Interface
146 Format: { force | off | ht | strict | noirq | rsdt }
147 force -- enable ACPI if default was off
148 off -- disable ACPI if default was on
149 noirq -- do not use ACPI for IRQ routing
150 ht -- run only enough ACPI to enable Hyper Threading
151 strict -- Be less tolerant of platforms that are not
152 strictly ACPI specification compliant.
153 rsdt -- prefer RSDT over (default) XSDT
155 See also Documentation/power/pm.txt, pci=noacpi
157 acpi_apic_instance= [ACPI, IOAPIC]
159 2: use 2nd APIC table, if available
160 1,0: use 1st APIC table
163 acpi_backlight= [HW,ACPI]
164 acpi_backlight=vendor
166 If set to vendor, prefer vendor specific driver
167 (e.g. thinkpad_acpi, sony_acpi, etc.) instead
168 of the ACPI video.ko driver.
170 acpi.debug_layer= [HW,ACPI,ACPI_DEBUG]
171 acpi.debug_level= [HW,ACPI,ACPI_DEBUG]
173 CONFIG_ACPI_DEBUG must be enabled to produce any ACPI
174 debug output. Bits in debug_layer correspond to a
175 _COMPONENT in an ACPI source file, e.g.,
176 #define _COMPONENT ACPI_PCI_COMPONENT
177 Bits in debug_level correspond to a level in
178 ACPI_DEBUG_PRINT statements, e.g.,
179 ACPI_DEBUG_PRINT((ACPI_DB_INFO, ...
180 The debug_level mask defaults to "info". See
181 Documentation/acpi/debug.txt for more information about
182 debug layers and levels.
184 Enable processor driver info messages:
185 acpi.debug_layer=0x20000000
186 Enable PCI/PCI interrupt routing info messages:
187 acpi.debug_layer=0x400000
188 Enable AML "Debug" output, i.e., stores to the Debug
189 object while interpreting AML:
190 acpi.debug_layer=0xffffffff acpi.debug_level=0x2
191 Enable all messages related to ACPI hardware:
192 acpi.debug_layer=0x2 acpi.debug_level=0xffffffff
194 Some values produce so much output that the system is
195 unusable. The "log_buf_len" parameter may be useful
196 if you need to capture more output.
198 acpi_display_output= [HW,ACPI]
199 acpi_display_output=vendor
200 acpi_display_output=video
203 acpi_irq_balance [HW,ACPI]
204 ACPI will balance active IRQs
207 acpi_irq_nobalance [HW,ACPI]
208 ACPI will not move active IRQs (default)
211 acpi_irq_isa= [HW,ACPI] If irq_balance, mark listed IRQs used by ISA
212 Format: <irq>,<irq>...
214 acpi_irq_pci= [HW,ACPI] If irq_balance, clear listed IRQs for
216 Format: <irq>,<irq>...
218 acpi_no_auto_ssdt [HW,ACPI] Disable automatic loading of SSDT
220 acpi_os_name= [HW,ACPI] Tell ACPI BIOS the name of the OS
221 Format: To spoof as Windows 98: ="Microsoft Windows"
223 acpi_osi= [HW,ACPI] Modify list of supported OS interface strings
224 acpi_osi="string1" # add string1 -- only one string
225 acpi_osi="!string2" # remove built-in string2
226 acpi_osi= # disable all strings
229 Override the pmtimer bug detection: force the kernel
230 to assume that this machine's pmtimer latches its value
231 and always returns good values.
233 acpi_sci= [HW,ACPI] ACPI System Control Interrupt trigger mode
234 Format: { level | edge | high | low }
236 acpi_serialize [HW,ACPI] force serialization of AML methods
238 acpi_skip_timer_override [HW,ACPI]
239 Recognize and ignore IRQ0/pin2 Interrupt Override.
240 For broken nForce2 BIOS resulting in XT-PIC timer.
242 acpi_sleep= [HW,ACPI] Sleep options
243 Format: { s3_bios, s3_mode, s3_beep, s4_nohwsig,
244 old_ordering, s4_nonvs, sci_force_enable }
245 See Documentation/power/video.txt for information on
247 s3_beep is for debugging; it makes the PC's speaker beep
248 as soon as the kernel's real-mode entry point is called.
249 s4_nohwsig prevents ACPI hardware signature from being
250 used during resume from hibernation.
251 old_ordering causes the ACPI 1.0 ordering of the _PTS
252 control method, with respect to putting devices into
253 low power states, to be enforced (the ACPI 2.0 ordering
254 of _PTS is used by default).
255 s4_nonvs prevents the kernel from saving/restoring the
256 ACPI NVS memory during hibernation.
257 sci_force_enable causes the kernel to set SCI_EN directly
258 on resume from S1/S3 (which is against the ACPI spec,
259 but some broken systems don't work without it).
261 acpi_use_timer_override [HW,ACPI]
262 Use timer override. For some broken Nvidia NF5 boards
263 that require a timer override, but don't have HPET
265 acpi_enforce_resources= [ACPI]
266 { strict | lax | no }
267 Check for resource conflicts between native drivers
268 and ACPI OperationRegions (SystemIO and SystemMemory
269 only). IO ports and memory declared in ACPI might be
270 used by the ACPI subsystem in arbitrary AML code and
271 can interfere with legacy drivers.
272 strict (default): access to resources claimed by ACPI
273 is denied; legacy drivers trying to access reserved
274 resources will fail to bind to device using them.
275 lax: access to resources claimed by ACPI is allowed;
276 legacy drivers trying to access reserved resources
277 will bind successfully but a warning message is logged.
278 no: ACPI OperationRegions are not marked as reserved,
279 no further checks are performed.
282 Format: <io>,<irq>,<dma>,<dma2>,<type>
284 add_efi_memmap [EFI; X86] Include EFI memory map in
285 kernel's map of available physical RAM.
288 See header of drivers/scsi/advansys.c.
290 advwdt= [HW,WDT] Advantech WDT
291 Format: <iostart>,<iostop>
293 aedsp16= [HW,OSS] Audio Excel DSP 16
294 Format: <io>,<irq>,<dma>,<mss_io>,<mpu_io>,<mpu_irq>
295 See also header of sound/oss/aedsp16.c.
298 { off | try_unsupported }
299 off: disable AGP support
300 try_unsupported: try to drive unsupported chipsets
301 (may crash computer or cause data corruption)
304 See Documentation/scsi/aha152x.txt.
307 Format: <portbase>[,<buson>,<busoff>[,<dmaspeed>]]
310 See Documentation/scsi/aic7xxx.txt.
313 See Documentation/scsi/aic79xx.txt.
315 amd_iommu= [HW,X86-84]
316 Pass parameters to the AMD IOMMU driver in the system.
318 isolate - enable device isolation (each device, as far
319 as possible, will get its own protection
321 share - put every device behind one IOMMU into the
322 same protection domain
323 fullflush - enable flushing of IO/TLB entries when
324 they are unmapped. Otherwise they are
325 flushed before they will be reused, which
328 amijoy.map= [HW,JOY] Amiga joystick support
329 Map of devices attached to JOY0DAT and JOY1DAT
331 See also Documentation/kernel/input/joystick.txt
333 analog.map= [HW,JOY] Analog joystick and gamepad support
334 Specifies type or capabilities of an analog joystick
335 connected to one of 16 gameports
336 Format: <type1>,<type2>,..<type16>
339 Power management functions (SPARCstation-4/5 + deriv.)
341 Disable APC CPU standby support. SPARCstation-Fox does
342 not play well with APC CPU idle - disable it if you have
343 APC and your system crashes randomly.
345 apic= [APIC,X86-32] Advanced Programmable Interrupt Controller
346 Change the output verbosity whilst booting
347 Format: { quiet (default) | verbose | debug }
348 Change the amount of debugging information output
349 when initialising the APIC and IO-APIC components.
352 See Documentation/networking/ipv6.txt.
354 show_lapic= [APIC,X86] Advanced Programmable Interrupt Controller
355 Limit apic dumping. The parameter defines the maximal
356 number of local apics being dumped. Also it is possible
357 to set it to "all" by meaning -- no limit here.
358 Format: { 1 (default) | 2 | ... | all }.
359 The parameter valid if only apic=debug or
360 apic=verbose is specified.
361 Example: apic=debug show_lapic=all
363 apm= [APM] Advanced Power Management
364 See header of arch/x86/kernel/apm_32.c.
366 arcrimi= [HW,NET] ARCnet - "RIM I" (entirely mem-mapped) cards
367 Format: <io>,<irq>,<nodeID>
371 atarimouse= [HW,MOUSE] Atari Mouse
373 atascsi= [HW,SCSI] Atari SCSI
375 atkbd.extra= [HW] Enable extra LEDs and keys on IBM RapidAccess,
376 EzKey and similar keyboards
378 atkbd.reset= [HW] Reset keyboard during initialization
380 atkbd.set= [HW] Select keyboard code set
381 Format: <int> (2 = AT (default), 3 = PS/2)
383 atkbd.scroll= [HW] Enable scroll wheel on MS Office and similar
386 atkbd.softraw= [HW] Choose between synthetic and real raw mode
387 Format: <bool> (0 = real, 1 = synthetic (default))
389 atkbd.softrepeat= [HW]
390 Use software keyboard repeat
394 baycom_epp= [HW,AX25]
397 baycom_par= [HW,AX25] BayCom Parallel Port AX.25 Modem
399 See header of drivers/net/hamradio/baycom_par.c.
401 baycom_ser_fdx= [HW,AX25]
402 BayCom Serial Port AX.25 Modem (Full Duplex Mode)
403 Format: <io>,<irq>,<mode>[,<baud>]
404 See header of drivers/net/hamradio/baycom_ser_fdx.c.
406 baycom_ser_hdx= [HW,AX25]
407 BayCom Serial Port AX.25 Modem (Half Duplex Mode)
408 Format: <io>,<irq>,<mode>
409 See header of drivers/net/hamradio/baycom_ser_hdx.c.
411 boot_delay= Milliseconds to delay each printk during boot.
412 Values larger than 10 seconds (10000) are changed to
416 bootmem_debug [KNL] Enable bootmem allocator debug messages.
418 bttv.card= [HW,V4L] bttv (bt848 + bt878 based grabber cards)
419 bttv.radio= Most important insmod options are available as
421 bttv.pll= See Documentation/video4linux/bttv/Insmod-options
422 bttv.tuner= and Documentation/video4linux/bttv/CARDLIST
425 See drivers/scsi/BusLogic.c, comment before function
426 BusLogic_ParseDriverOptions().
428 c101= [NET] Moxa C101 synchronous serial card
430 cachesize= [BUGS=X86-32] Override level 2 CPU cache size detection.
431 Sometimes CPU hardware bugs make them report the cache
432 size incorrectly. The kernel will attempt work arounds
433 to fix known problems, but for some CPUs it is not
434 possible to determine what the correct size should be.
435 This option provides an override for these situations.
438 [SECURITY] Disable capabilities. This would normally
439 be used only if an alternative security model is to be
440 configured. Potentially dangerous and should only be
441 used if you are entirely sure of the consequences.
443 ccw_timeout_log [S390]
444 See Documentation/s390/CommonIO for details.
446 cgroup_disable= [KNL] Disable a particular controller
447 Format: {name of the controller(s) to disable}
448 {Currently supported controllers - "memory"}
450 checkreqprot [SELINUX] Set initial checkreqprot flag value.
451 Format: { "0" | "1" }
452 See security/selinux/Kconfig help text.
453 0 -- check protection applied by kernel (includes
454 any implied execute protection).
455 1 -- check protection requested by application.
456 Default value is set via a kernel config option.
457 Value can be changed at runtime via
458 /selinux/checkreqprot.
461 See Documentation/s390/CommonIO for details.
463 clock= [BUGS=X86-32, HW] gettimeofday clocksource override.
465 Forces specified clocksource (if available) to be used
466 when calculating gettimeofday(). If specified
467 clocksource is not available, it defaults to PIT.
468 Format: { pit | tsc | cyclone | pmtmr }
470 clocksource= [GENERIC_TIME] Override the default clocksource
472 Override the default clocksource and use the clocksource
473 with the name specified.
474 Some clocksource names to choose from, depending on
476 [all] jiffies (this is the base, fallback clocksource)
478 [ARM] imx_timer1,OSTS,netx_timer,mpu_timer2,
479 pxa_timer,timer3,32k_counter,timer0_1
481 [X86-32] pit,hpet,tsc,vmi-timer;
482 scx200_hrt on Geode; cyclone on IBM x440
490 clearcpuid=BITNUM [X86]
491 Disable CPUID feature X for the kernel. See
492 arch/x86/include/asm/cpufeature.h for the valid bit
493 numbers. Note the Linux specific bits are not necessarily
494 stable over kernel options, but the vendor specific
496 Also note that user programs calling CPUID directly
497 or using the feature without checking anything
498 will still see it. This just prevents it from
499 being used by the kernel or shown in /proc/cpuinfo.
500 Also note the kernel might malfunction if you disable
503 cmo_free_hint= [PPC] Format: { yes | no }
504 Specify whether pages are marked as being inactive
505 when they are freed. This is used in CMO environments
506 to determine OS memory pressure for page stealing by
510 code_bytes [X86] How many bytes of object code to print
515 com20020= [HW,NET] ARCnet - COM20020 chipset
517 <io>[,<irq>[,<nodeID>[,<backplane>[,<ckp>[,<timeout>]]]]]
519 com90io= [HW,NET] ARCnet - COM90xx chipset (IO-mapped buffers)
523 ARCnet - COM90xx chipset (memory-mapped buffers)
524 Format: <io>[,<irq>[,<memstart>]]
526 condev= [HW,S390] console device
529 console= [KNL] Output console device and options.
531 tty<n> Use the virtual console device <n>.
535 Use the specified serial port. The options are of
536 the form "bbbbpnf", where "bbbb" is the baud rate,
537 "p" is parity ("n", "o", or "e"), "n" is number of
538 bits, and "f" is flow control ("r" for RTS or
539 omit it). Default is "9600n8".
541 See Documentation/serial-console.txt for more
543 Documentation/networking/netconsole.txt for an
546 uart[8250],io,<addr>[,options]
547 uart[8250],mmio,<addr>[,options]
548 Start an early, polled-mode console on the 8250/16550
549 UART at the specified I/O port or MMIO address,
550 switching to the matching ttyS device later. The
551 options are the same as for ttyS, above.
553 If the device connected to the port is not a TTY but a braille
554 device, prepend "brl," before the device type, for instance
556 For now, only VisioBraille is supported.
558 consoleblank= [KNL] The console blank (screen saver) timeout in
559 seconds. Defaults to 10*60 = 10mins. A value of 0
560 disables the blank timer.
563 [KNL] Change the default value for
564 /proc/<pid>/coredump_filter.
565 See also Documentation/filesystems/proc.txt.
567 cpcihp_generic= [HW,PCI] Generic port I/O CompactPCI driver
569 <first_slot>,<last_slot>,<port>,<enum_bit>[,<debug>]
571 crashkernel=nn[KMG]@ss[KMG]
572 [KNL] Reserve a chunk of physical memory to
573 hold a kernel to switch to with kexec on panic.
575 crashkernel=range1:size1[,range2:size2,...][@offset]
576 [KNL] Same as above, but depends on the memory
577 in the running system. The syntax of range is
578 start-[end] where start and end are both
579 a memory unit (amount[KMG]). See also
580 Documentation/kdump/kdump.txt for a example.
585 cs89x0_media= [HW,NET]
586 Format: { rj45 | aui | bnc }
589 See header of drivers/s390/block/dasd_devmap.c.
591 db9.dev[2|3]= [HW,JOY] Multisystem joystick support via parallel port
592 (one device per port)
593 Format: <port#>,<type>
594 See also Documentation/input/joystick-parport.txt
596 debug [KNL] Enable kernel debugging (events log level).
599 [KNL] verbose self-tests
601 Print debugging info while doing the locking API
603 We default to 0 (no extra messages), setting it to
604 1 will print _a lot_ more information - normally
605 only useful to kernel developers.
607 debug_objects [KNL] Enable object debugging
610 [KNL] Disable object debugging
612 debugpat [X86] Enable PAT debugging
614 decnet.addr= [HW,NET]
615 Format: <area>[,<node>]
616 See also Documentation/networking/decnet.txt.
619 [same as hugepagesz=] The size of the default
620 HugeTLB page size. This is the size represented by
621 the legacy /proc/ hugepages APIs, used for SHM, and
622 default size when mounting hugetlbfs filesystems.
623 Defaults to the default architecture's huge page size
627 Set number of hash buckets for dentry cache.
630 IO parameters + enable/disable command.
632 digiepca= [HW,SERIAL]
633 See drivers/char/README.epca and
634 Documentation/serial/digiepca.txt.
637 See Documentation/networking/ipv6.txt.
640 See Documentation/networking/ipv6.txt.
642 disable_mtrr_cleanup [X86]
643 The kernel tries to adjust MTRR layout from continuous
644 to discrete, to make X server driver able to add WB
645 entry later. This parameter disables that.
647 disable_mtrr_trim [X86, Intel and AMD only]
648 By default the kernel will trim any uncacheable
649 memory out of your available memory pool based on
650 MTRR settings. This parameter disables that behavior,
651 possibly causing your machine to run very slowly.
653 disable_timer_pin_1 [X86]
654 Disable PIN 1 of APIC timer
655 Can be useful to work around chipset bugs.
657 dmasound= [HW,OSS] Sound subsystem buffers
659 dma_debug=off If the kernel is compiled with DMA_API_DEBUG support,
660 this option disables the debugging code at boot.
662 dma_debug_entries=<number>
663 This option allows to tune the number of preallocated
664 entries for DMA-API debugging code. One entry is
665 required per DMA-API allocation. Use this if the
666 DMA-API debugging code disables itself because the
667 architectural default is too low.
669 dma_debug_driver=<driver_name>
670 With this option the DMA-API debugging driver
671 filter feature can be enabled at boot time. Just
672 pass the driver to filter for as the parameter.
673 The filter can be disabled or changed to another
674 driver later using sysfs.
680 dynamic_printk Enables pr_debug()/dev_dbg() calls if
681 CONFIG_DYNAMIC_PRINTK_DEBUG has been enabled.
682 These can also be switched on/off via
683 <debugfs>/dynamic_printk/modules
685 earlycon= [KNL] Output early console device and options.
686 uart[8250],io,<addr>[,options]
687 uart[8250],mmio,<addr>[,options]
688 Start an early, polled-mode console on the 8250/16550
689 UART at the specified I/O port or MMIO address.
690 The options are the same as for ttyS, above.
692 earlyprintk= [X86,SH,BLACKFIN]
694 earlyprintk=serial[,ttySn[,baudrate]]
695 earlyprintk=ttySn[,baudrate]
696 earlyprintk=dbgp[debugController#]
698 Append ",keep" to not disable it when the real console
701 Only vga or serial or usb debug port at a time.
703 Currently only ttyS0 and ttyS1 are supported.
705 Interaction with the standard serial driver is not
708 The VGA output is eventually overwritten by the real
714 Format: {"off" | "on" | "skip[mbr]"}
716 eisa_irq_edge= [PARISC,HW]
717 See header of drivers/parisc/eisa.c.
720 See comment before function elanfreq_setup() in
721 arch/x86/kernel/cpu/cpufreq/elanfreq.c.
724 Format: {"anticipatory" | "cfq" | "deadline" | "noop"}
725 See Documentation/block/as-iosched.txt and
726 Documentation/block/deadline-iosched.txt for details.
728 elfcorehdr= [IA64,PPC,SH,X86]
729 Specifies physical address of start of kernel core
730 image elf header. Generally kexec loader will
731 pass this option to capture kernel.
732 See Documentation/kdump/kdump.txt for details.
734 enable_mtrr_cleanup [X86]
735 The kernel tries to adjust MTRR layout from continuous
736 to discrete, to make X server driver able to add WB
737 entry later. This parameter enables that.
739 enable_timer_pin_1 [X86]
740 Enable PIN 1 of APIC timer
741 Can be useful to work around chipset bugs
742 (in particular on some ATI chipsets).
743 The kernel tries to set a reasonable default.
745 enforcing [SELINUX] Set initial enforcing status.
747 See security/selinux/Kconfig help text.
748 0 -- permissive (log only, no denials).
749 1 -- enforcing (deny and log).
751 Value can be changed at runtime via /selinux/enforce.
753 ether= [HW,NET] Ethernet cards parameters
754 This option is obsoleted by the "netdev=" option, which
755 has equivalent usage. See its documentation for details.
757 eurwdt= [HW,WDT] Eurotech CPU-1220/1410 onboard watchdog.
762 fail_make_request=[KNL]
763 General fault injection mechanism.
764 Format: <interval>,<probability>,<space>,<times>
765 See also /Documentation/fault-injection/.
768 See header of drivers/scsi/fd_mcs.c.
771 See header of drivers/scsi/fdomain.c.
774 See Documentation/blockdev/floppy.txt.
776 force_pal_cache_flush
777 [IA-64] Avoid check_sal_cache_flush which may hang on
778 buggy SAL_CACHE_FLUSH implementations. Using this
779 parameter will force ia64_sal_cache_flush to call
780 ia64_pal_cache_flush instead of SAL_CACHE_FLUSH.
783 [FTRACE] will set and start the specified tracer
784 as early as possible in order to facilitate early
788 [FTRACE] will dump the trace buffers on oops.
790 ftrace_filter=[function-list]
791 [FTRACE] Limit the functions traced by the function
792 tracer at boot up. function-list is a comma separated
793 list of functions. This list can be changed at run
794 time by the set_ftrace_filter file in the debugfs
797 ftrace_notrace=[function-list]
798 [FTRACE] Do not trace the functions specified in
799 function-list. This list can be changed at run time
800 by the set_ftrace_notrace file in the debugfs
803 ftrace_graph_filter=[function-list]
804 [FTRACE] Limit the top level callers functions traced
805 by the function graph tracer at boot up.
806 function-list is a comma separated list of functions
807 that can be changed at run time by the
808 set_graph_function file in the debugfs tracing directory.
811 [HW,JOY] Multisystem joystick and NES/SNES/PSX pad
812 support via parallel port (up to 5 devices per port)
813 Format: <port#>,<pad1>,<pad2>,<pad3>,<pad4>,<pad5>
814 See also Documentation/input/joystick-parport.txt
818 gart_fix_e820= [X86_64] disable the fix e820 for K8 GART
822 gcov_persist= [GCOV] When non-zero (default), profiling data for
823 kernel modules is saved and remains accessible via
824 debugfs, even when the module is unloaded/reloaded.
825 When zero, profiling data is discarded and associated
826 debugfs files are removed at module unload time.
829 See header of drivers/scsi/gdth.c.
831 gpt [EFI] Forces disk with valid GPT signature but
832 invalid Protective MBR to be treated as GPT.
836 hashdist= [KNL,NUMA] Large hashes allocated during boot
837 are distributed across NUMA nodes. Defaults on
838 for 64bit NUMA, off otherwise.
839 Format: 0 | 1 (for off | on)
841 hcl= [IA-64] SGI's Hardware Graph compatibility layer
843 hd= [EIDE] (E)IDE hard drive subsystem geometry
844 Format: <cyl>,<head>,<sect>
846 highmem=nn[KMG] [KNL,BOOT] forces the highmem zone to have an exact
847 size of <nn>. This works even on boxes that have no
848 highmem otherwise. This also works to reduce highmem
849 size on bigger boxes.
851 highres= [KNL] Enable/disable high resolution timer mode.
852 Valid parameters: "on", "off"
856 See Documentation/isdn/README.HiSax.
860 hpet= [X86-32,HPET] option to control HPET usage
861 Format: { enable (default) | disable | force |
863 disable: disable HPET and use PIT instead
864 force: allow force enabled of undocumented chips (ICH4,
866 verbose: show contents of HPET registers during setup
868 hugepages= [HW,X86-32,IA-64] HugeTLB pages to allocate at boot.
869 hugepagesz= [HW,IA-64,PPC,X86-64] The size of the HugeTLB pages.
870 On x86-64 and powerpc, this option can be specified
871 multiple times interleaved with hugepages= to reserve
872 huge pages of different sizes. Valid pages sizes on
873 x86-64 are 2M (when the CPU supports "pse") and 1G
874 (when the CPU supports the "pdpe1gb" cpuinfo flag)
875 Note that 1GB pages can only be allocated at boot time
876 using hugepages= and not freed afterwards.
878 hvc_iucv= [S390] Number of z/VM IUCV hypervisor console (HVC)
879 terminal devices. Valid values: 0..8
880 hvc_iucv_allow= [S390] Comma-separated list of z/VM user IDs.
881 If specified, z/VM IUCV HVC accepts connections
882 from listed z/VM user IDs only.
884 i2c_bus= [HW] Override the default board specific I2C bus speed
885 or register an additional I2C bus that is not
886 registered from board initialization code.
890 i8042.debug [HW] Toggle i8042 debug mode
891 i8042.direct [HW] Put keyboard port into non-translated mode
892 i8042.dumbkbd [HW] Pretend that controller can only read data from
893 keyboard and cannot control its state
894 (Don't attempt to blink the leds)
895 i8042.noaux [HW] Don't check for auxiliary (== mouse) port
896 i8042.nokbd [HW] Don't check/create keyboard port
897 i8042.noloop [HW] Disable the AUX Loopback command while probing
899 i8042.nomux [HW] Don't check presence of an active multiplexing
901 i8042.nopnp [HW] Don't use ACPIPnP / PnPBIOS to discover KBD/AUX
904 [HW] Frequency with which keyboard LEDs should blink
905 when kernel panics (default is 0.5 sec)
906 i8042.reset [HW] Reset the controller during init and cleanup
907 i8042.unlock [HW] Unlock (ignore) the keylock
911 i8k.ignore_dmi [HW] Continue probing hardware even if DMI data
912 indicates that the driver is running on unsupported
914 i8k.force [HW] Activate i8k driver even if SMM BIOS signature
915 does not match list of supported models.
917 [HW] Report power status in /proc/i8k
918 (disabled by default)
919 i8k.restricted [HW] Allow controlling fans only if SYS_ADMIN
922 ibmmcascsi= [HW,MCA,SCSI] IBM MicroChannel SCSI adapter
923 See Documentation/mca.txt.
926 Format: <io>[,<membase>[,<icn_id>[,<icn_id2>]]]
928 ide-core.nodma= [HW] (E)IDE subsystem
929 Format: =0.0 to prevent dma on hda, =0.1 hdb =1.0 hdc
930 .vlb_clock .pci_clock .noflush .nohpa .noprobe .nowerr
931 .cdrom .chs .ignore_cable are additional options
932 See Documentation/ide/ide.txt.
934 ide-pci-generic.all-generic-ide [HW] (E)IDE subsystem
935 Claim all unknown PCI IDE storage controllers.
938 Format: idle=poll, idle=mwait, idle=halt, idle=nomwait
939 Poll forces a polling idle loop that can slightly
940 improve the performance of waking up a idle CPU, but
941 will use a lot of power and make the system run hot.
943 idle=mwait: On systems which support MONITOR/MWAIT but
944 the kernel chose to not use it because it doesn't save
945 as much power as a normal idle loop, use the
946 MONITOR/MWAIT idle loop anyways. Performance should be
947 the same as idle=poll.
948 idle=halt: Halt is forced to be used for CPU idle.
949 In such case C2/C3 won't be used again.
950 idle=nomwait: Disable mwait for CPU C-states
952 ignore_loglevel [KNL]
953 Ignore loglevel setting - this will print /all/
954 kernel messages to the console. Useful for debugging.
957 Set number of hash buckets for inode cache.
960 Format: { "0" | "1" }
961 0 -- integrity auditing messages. (Default)
962 1 -- enable informational integrity auditing messages.
965 Format: { "sha1" | "md5" }
969 Load a policy which meets the needs of the Trusted
970 Computing Base. This means IMA will measure all
971 programs exec'd, files mmap'd for exec, and all files
972 opened for read by uid=0.
975 See header of drivers/scsi/in2000.c.
979 Run specified binary instead of /sbin/init as init
982 initcall_debug [KNL] Trace initcalls as they are executed. Useful
983 for working out where the kernel is dying during
986 initrd= [BOOT] Specify the location of the initial ramdisk
988 inport.irq= [HW] Inport (ATI XL and Microsoft) busmouse driver
991 intel_iommu= [DMAR] Intel IOMMU driver (DMAR) option
993 Enable intel iommu driver.
995 Disable intel iommu driver.
996 igfx_off [Default Off]
997 By default, gfx is mapped as normal device. If a gfx
998 device has a dedicated DMAR unit, the DMAR unit is
999 bypassed by not enabling DMAR with this option. In
1000 this case, gfx device will use physical address for
1003 With this option iommu will not optimize to look
1004 for io virtual address below 32 bit forcing dual
1005 address cycle on pci bus for cards supporting greater
1006 than 32 bit addressing. The default is to look
1007 for translation below 32 bit and if not available
1008 then look in the higher range.
1009 strict [Default Off]
1010 With this option on every unmap_single operation will
1011 result in a hardware IOTLB flush operation as opposed
1012 to batching them for performance.
1016 iomem= Disable strict checking of access to MMIO memory
1017 strict regions from userspace.
1033 io7= [HW] IO7 for Marvel based alpha systems
1034 See comment before marvel_specify_io7 in
1035 arch/alpha/kernel/core_marvel.c.
1037 io_delay= [X86] I/O delay method
1039 Standard port 0x80 based delay
1041 Alternate port 0xed based delay (needed on some systems)
1043 Simple two microseconds delay
1048 See Documentation/filesystems/nfs/nfsroot.txt.
1050 ip2= [HW] Set IO/IRQ pairs for up to 4 IntelliPort boards
1051 See comment before ip2_setup() in
1052 drivers/char/ip2/ip2base.c.
1054 ips= [HW,SCSI] Adaptec / IBM ServeRAID controller
1055 See header of drivers/scsi/ips.c.
1058 When an interrupt is not handled search all handlers
1059 for it. Intended to get systems with badly broken
1063 When an interrupt is not handled search all handlers
1064 for it. Also check all handlers each timer
1065 interrupt. Intended to get systems with badly broken
1069 Format: <RDP>,<reset>,<pci_scan>,<verbosity>
1071 isolcpus= [KNL,SMP] Isolate CPUs from the general scheduler.
1073 <cpu number>,...,<cpu number>
1075 <cpu number>-<cpu number>
1076 (must be a positive range in ascending order)
1078 <cpu number>,...,<cpu number>-<cpu number>
1080 This option can be used to specify one or more CPUs
1081 to isolate from the general SMP balancing and scheduling
1082 algorithms. You can move a process onto or off an
1083 "isolated" CPU via the CPU affinity syscalls or cpuset.
1084 <cpu number> begins at 0 and the maximum value is
1085 "number of CPUs in system - 1".
1087 This option is the preferred way to isolate CPUs. The
1088 alternative -- manually setting the CPU mask of all
1089 tasks in the system -- can cause problems and
1090 suboptimal load balancer performance.
1094 js= [HW,JOY] Analog joystick
1095 See Documentation/input/joystick.txt.
1099 kernelcore=nn[KMG] [KNL,X86,IA-64,PPC] This parameter
1100 specifies the amount of memory usable by the kernel
1101 for non-movable allocations. The requested amount is
1102 spread evenly throughout all nodes in the system. The
1103 remaining memory in each node is used for Movable
1104 pages. In the event, a node is too small to have both
1105 kernelcore and Movable pages, kernelcore pages will
1106 take priority and other nodes will have a larger number
1107 of kernelcore pages. The Movable zone is used for the
1108 allocation of pages that may be reclaimed or moved
1109 by the page migration subsystem. This means that
1110 HugeTLB pages may not be allocated from this zone.
1111 Note that allocations like PTEs-from-HighMem still
1112 use the HighMem zone if it exists, and the Normal
1113 zone if it does not.
1115 kgdboc= [HW] kgdb over consoles.
1116 Requires a tty driver that supports console polling.
1117 (only serial supported for now)
1118 Format: <serial_device>[,baud]
1120 kmac= [MIPS] korina ethernet MAC address.
1121 Configure the RouterBoard 532 series on-chip
1122 Ethernet adapter MAC address.
1124 kmemleak= [KNL] Boot-time kmemleak enable/disable
1125 Valid arguments: on, off
1128 kstack=N [X86] Print N words from the kernel stack
1131 kvm.ignore_msrs=[KVM] Ignore guest accesses to unhandled MSRs.
1132 Default is 0 (don't ignore, but inject #GP)
1134 kvm.oos_shadow= [KVM] Disable out-of-sync shadow paging.
1135 Default is 1 (enabled)
1137 kvm-amd.nested= [KVM,AMD] Allow nested virtualization in KVM/SVM.
1140 kvm-amd.npt= [KVM,AMD] Disable nested paging (virtualized MMU)
1142 Default is 1 (enabled) if in 64bit or 32bit-PAE mode
1144 kvm-intel.bypass_guest_pf=
1145 [KVM,Intel] Disables bypassing of guest page faults
1146 on Intel chips. Default is 1 (enabled)
1148 kvm-intel.ept= [KVM,Intel] Disable extended page tables
1149 (virtualized MMU) support on capable Intel chips.
1150 Default is 1 (enabled)
1152 kvm-intel.emulate_invalid_guest_state=
1153 [KVM,Intel] Enable emulation of invalid guest states
1154 Default is 0 (disabled)
1156 kvm-intel.flexpriority=
1157 [KVM,Intel] Disable FlexPriority feature (TPR shadow).
1158 Default is 1 (enabled)
1160 kvm-intel.unrestricted_guest=
1161 [KVM,Intel] Disable unrestricted guest feature
1162 (virtualized real and unpaged mode) on capable
1163 Intel chips. Default is 1 (enabled)
1165 kvm-intel.vpid= [KVM,Intel] Disable Virtual Processor Identification
1166 feature (tagged TLBs) on capable Intel chips.
1167 Default is 1 (enabled)
1173 lapic [X86-32,APIC] Enable the local APIC even if BIOS
1176 lapic_timer_c2_ok [X86,APIC] trust the local apic timer
1179 libata.dma= [LIBATA] DMA control
1180 libata.dma=0 Disable all PATA and SATA DMA
1181 libata.dma=1 PATA and SATA Disk DMA only
1182 libata.dma=2 ATAPI (CDROM) DMA only
1183 libata.dma=4 Compact Flash DMA only
1184 Combinations also work, so libata.dma=3 enables DMA
1185 for disks and CDROMs, but not CFs.
1187 libata.ignore_hpa= [LIBATA] Ignore HPA limit
1188 libata.ignore_hpa=0 keep BIOS limits (default)
1189 libata.ignore_hpa=1 ignore limits, using full disk
1191 libata.noacpi [LIBATA] Disables use of ACPI in libata suspend/resume
1195 libata.force= [LIBATA] Force configurations. The format is comma
1196 separated list of "[ID:]VAL" where ID is
1197 PORT[:DEVICE]. PORT and DEVICE are decimal numbers
1198 matching port, link or device. Basically, it matches
1199 the ATA ID string printed on console by libata. If
1200 the whole ID part is omitted, the last PORT and DEVICE
1201 values are used. If ID hasn't been specified yet, the
1202 configuration applies to all ports, links and devices.
1204 If only DEVICE is omitted, the parameter applies to
1205 the port and all links and devices behind it. DEVICE
1206 number of 0 either selects the first device or the
1207 first fan-out link behind PMP device. It does not
1208 select the host link. DEVICE number of 15 selects the
1209 host link and device attached to it.
1211 The VAL specifies the configuration to force. As long
1212 as there's no ambiguity shortcut notation is allowed.
1213 For example, both 1.5 and 1.5G would work for 1.5Gbps.
1214 The following configurations can be forced.
1216 * Cable type: 40c, 80c, short40c, unk, ign or sata.
1217 Any ID with matching PORT is used.
1219 * SATA link speed limit: 1.5Gbps or 3.0Gbps.
1221 * Transfer mode: pio[0-7], mwdma[0-4] and udma[0-7].
1222 udma[/][16,25,33,44,66,100,133] notation is also
1225 * [no]ncq: Turn on or off NCQ.
1227 * nohrst, nosrst, norst: suppress hard, soft
1230 If there are multiple matching configurations changing
1231 the same attribute, the last one is used.
1233 lmb=debug [KNL] Enable lmb debug messages.
1235 load_ramdisk= [RAM] List of ramdisks to load from floppy
1236 See Documentation/blockdev/ramdisk.txt.
1238 lockd.nlm_grace_period=P [NFS] Assign grace period.
1241 lockd.nlm_tcpport=N [NFS] Assign TCP port.
1244 lockd.nlm_timeout=T [NFS] Assign timeout value.
1247 lockd.nlm_udpport=M [NFS] Assign UDP port.
1250 logibm.irq= [HW,MOUSE] Logitech Bus Mouse Driver
1253 loglevel= All Kernel Messages with a loglevel smaller than the
1254 console loglevel will be printed to the console. It can
1255 also be changed with klogd or other programs. The
1256 loglevels are defined as follows:
1258 0 (KERN_EMERG) system is unusable
1259 1 (KERN_ALERT) action must be taken immediately
1260 2 (KERN_CRIT) critical conditions
1261 3 (KERN_ERR) error conditions
1262 4 (KERN_WARNING) warning conditions
1263 5 (KERN_NOTICE) normal but significant condition
1264 6 (KERN_INFO) informational
1265 7 (KERN_DEBUG) debug-level messages
1267 log_buf_len=n Sets the size of the printk ring buffer, in bytes.
1268 Format: { n | nk | nM }
1269 n must be a power of two. The default size
1270 is set in the kernel config file.
1272 logo.nologo [FB] Disables display of the built-in Linux logo.
1273 This may be used to provide more screen space for
1274 kernel log messages and is useful when debugging
1275 kernel boot problems.
1277 lp=0 [LP] Specify parallel ports to use, e.g,
1278 lp=port[,port...] lp=none,parport0 (lp0 not configured, lp1 uses
1279 lp=reset first parallel port). 'lp=0' disables the
1280 lp=auto printer driver. 'lp=reset' (which can be
1281 specified in addition to the ports) causes
1282 attached printers to be reset. Using
1283 lp=port1,port2,... specifies the parallel ports
1284 to associate lp devices with, starting with
1285 lp0. A port specification may be 'none' to skip
1286 that lp device, or a parport name such as
1287 'parport0'. Specifying 'lp=auto' instead of a
1288 port specification list means that device IDs
1289 from each port should be examined, to see if
1290 an IEEE 1284-compliant printer is attached; if
1291 so, the driver will manage that printer.
1292 See also header of drivers/char/lp.c.
1295 Sets loops_per_jiffy to given constant, thus avoiding
1296 time-consuming boot-time autodetection (up to 250 ms per
1297 CPU). 0 enables autodetection (default). To determine
1298 the correct value for your kernel, boot with normal
1299 autodetection and see what value is printed. Note that
1300 on SMP systems the preset will be applied to all CPUs,
1301 which is likely to cause problems if your CPUs need
1302 significantly divergent settings. An incorrect value
1303 will cause delays in the kernel to be wrong, leading to
1304 unpredictable I/O errors and other breakage. Although
1305 unlikely, in the extreme case this might damage your
1309 Format: <io>,<irq>,<dma>
1311 mac5380= [HW,SCSI] Format:
1312 <can_queue>,<cmd_per_lun>,<sg_tablesize>,<hostid>,<use_tags>
1314 machvec= [IA64] Force the use of a particular machine-vector
1315 (machvec) in a generic kernel.
1316 Example: machvec=hpzx1_swiotlb
1318 machtype= [Loongson] Share the same kernel image file between different
1320 Example: machtype=lemote-yeeloong-2f-7inch
1322 max_addr=nn[KMG] [KNL,BOOT,ia64] All physical memory greater
1323 than or equal to this physical address is ignored.
1325 maxcpus= [SMP] Maximum number of processors that an SMP kernel
1326 should make use of. maxcpus=n : n >= 0 limits the
1327 kernel to using 'n' processors. n=0 is a special case,
1328 it is equivalent to "nosmp", which also disables
1331 max_loop= [LOOP] Maximum number of loopback devices that can
1335 max_luns= [SCSI] Maximum number of LUNs to probe.
1336 Should be between 1 and 2^32-1.
1339 [SCSI] Maximum number of LUNs received.
1340 Should be between 1 and 16384.
1344 mce [X86-32] Machine Check Exception
1346 mce=option [X86-64] See Documentation/x86/x86_64/boot-options.txt
1348 md= [HW] RAID subsystems devices and level
1349 See Documentation/md.txt.
1352 Format: <first>,<last>
1353 Specifies range of consoles to be captured by the MDA.
1355 mem=nn[KMG] [KNL,BOOT] Force usage of a specific amount of memory
1356 Amount of memory to be used when the kernel is not able
1357 to see the whole system memory or for test.
1358 [X86-32] Use together with memmap= to avoid physical
1359 address space collisions. Without memmap= PCI devices
1360 could be placed at addresses belonging to unused RAM.
1362 mem=nopentium [BUGS=X86-32] Disable usage of 4MB pages for kernel
1366 [KNL,SH] Allow user to override the default size for
1367 per-device physically contiguous DMA buffers.
1369 memmap=exactmap [KNL,X86] Enable setting of an exact
1370 E820 memory map, as specified by the user.
1371 Such memmap=exactmap lines can be constructed based on
1372 BIOS output or other requirements. See the memmap=nn@ss
1375 memmap=nn[KMG]@ss[KMG]
1376 [KNL] Force usage of a specific region of memory
1377 Region of memory to be used, from ss to ss+nn.
1379 memmap=nn[KMG]#ss[KMG]
1380 [KNL,ACPI] Mark specific memory as ACPI data.
1381 Region of memory to be used, from ss to ss+nn.
1383 memmap=nn[KMG]$ss[KMG]
1384 [KNL,ACPI] Mark specific memory as reserved.
1385 Region of memory to be used, from ss to ss+nn.
1386 Example: Exclude memory from 0x18690000-0x1869ffff
1387 memmap=64K$0x18690000
1389 memmap=0x10000$0x18690000
1391 memory_corruption_check=0/1 [X86]
1392 Some BIOSes seem to corrupt the first 64k of
1393 memory when doing things like suspend/resume.
1394 Setting this option will scan the memory
1395 looking for corruption. Enabling this will
1396 both detect corruption and prevent the kernel
1397 from using the memory being corrupted.
1398 However, its intended as a diagnostic tool; if
1399 repeatable BIOS-originated corruption always
1400 affects the same memory, you can use memmap=
1401 to prevent the kernel from using that memory.
1403 memory_corruption_check_size=size [X86]
1404 By default it checks for corruption in the low
1405 64k, making this memory unavailable for normal
1406 use. Use this parameter to scan for
1407 corruption in more or less memory.
1409 memory_corruption_check_period=seconds [X86]
1410 By default it checks for corruption every 60
1411 seconds. Use this parameter to check at some
1412 other rate. 0 disables periodic checking.
1414 memtest= [KNL,X86] Enable memtest
1416 default : 0 <disable>
1417 Specifies the number of memtest passes to be
1418 performed. Each pass selects another test
1419 pattern from a given set of patterns. Memtest
1420 fills the memory with this pattern, validates
1421 memory contents and reserves bad memory
1422 regions that are detected.
1424 meye.*= [HW] Set MotionEye Camera parameters
1425 See Documentation/video4linux/meye.txt.
1427 mfgpt_irq= [IA-32] Specify the IRQ to use for the
1428 Multi-Function General Purpose Timers on AMD Geode
1431 mfgptfix [X86-32] Fix MFGPT timers on AMD Geode platforms when
1432 the BIOS has incorrectly applied a workaround. TinyBIOS
1433 version 0.98 is known to be affected, 0.99 fixes the
1434 problem by letting the user disable the workaround.
1438 min_addr=nn[KMG] [KNL,BOOT,ia64] All physical memory below this
1439 physical address is ignored.
1441 mini2440= [ARM,HW,KNL]
1442 Format:[0..2][b][c][t]
1444 MINI2440 configuration specification:
1445 0 - The attached screen is the 3.5" TFT
1446 1 - The attached screen is the 7" TFT
1447 2 - The VGA Shield is attached (1024x768)
1448 Leaving out the screen size parameter will not load
1449 the TFT driver, and the framebuffer will be left
1451 b - Enable backlight. The TFT backlight pin will be
1452 linked to the kernel VESA blanking code and a GPIO
1453 LED. This parameter is not necessary when using the
1455 c - Enable the s3c camera interface.
1456 t - Reserved for enabling touchscreen support. The
1457 touchscreen support is not enabled in the mainstream
1458 kernel as of 2.6.30, a preliminary port can be found
1459 in the "bleeding edge" mini2440 support kernel at
1460 http://repo.or.cz/w/linux-2.6/mini2440.git
1463 [KNL] When CONFIG_DEBUG_MEMORY_INIT is set, this
1464 parameter allows control of the logging verbosity for
1465 the additional memory initialisation checks. A value
1466 of 0 disables mminit logging and a level of 4 will
1467 log everything. Information is printed at KERN_DEBUG
1468 so loglevel=8 may also need to be specified.
1471 [MOUSE] Maximum time between finger touching and
1472 leaving touchpad surface for touch to be considered
1473 a tap and be reported as a left button click (for
1474 touchpads working in absolute mode only).
1476 mousedev.xres= [MOUSE] Horizontal screen resolution, used for devices
1477 reporting absolute coordinates, such as tablets
1478 mousedev.yres= [MOUSE] Vertical screen resolution, used for devices
1479 reporting absolute coordinates, such as tablets
1481 movablecore=nn[KMG] [KNL,X86,IA-64,PPC] This parameter
1482 is similar to kernelcore except it specifies the
1483 amount of memory used for migratable allocations.
1484 If both kernelcore and movablecore is specified,
1485 then kernelcore will be at *least* the specified
1486 value but may be more. If movablecore on its own
1487 is specified, the administrator must be careful
1488 that the amount of memory usable for all allocations
1494 MTD_Partition= [MTD]
1495 Format: <name>,<region-number>,<size>,<offset>
1497 MTD_Region= [MTD] Format:
1498 <name>,<region-number>[,<base>,<size>,<buswidth>,<altbuswidth>]
1501 See drivers/mtd/cmdlinepart.c.
1503 onenand.bdry= [HW,MTD] Flex-OneNAND Boundary Configuration
1505 Format: [die0_boundary][,die0_lock][,die1_boundary][,die1_lock]
1507 boundary - index of last SLC block on Flex-OneNAND.
1508 The remaining blocks are configured as MLC blocks.
1509 lock - Configure if Flex-OneNAND boundary should be locked.
1510 Once locked, the boundary cannot be changed.
1511 1 indicates lock status, 0 indicates unlock status.
1514 ARM/S3C2412 JIVE boot control
1516 See arch/arm/mach-s3c2412/mach-jive.c
1518 mtouchusb.raw_coordinates=
1519 [HW] Make the MicroTouch USB driver use raw coordinates
1520 ('y', default) or cooked coordinates ('n')
1522 mtrr_chunk_size=nn[KMG] [X86]
1523 used for mtrr cleanup. It is largest continuous chunk
1524 that could hold holes aka. UC entries.
1526 mtrr_gran_size=nn[KMG] [X86]
1527 Used for mtrr cleanup. It is granularity of mtrr block.
1529 Large value could prevent small alignment from
1532 mtrr_spare_reg_nr=n [X86]
1534 Range: 0,7 : spare reg number
1536 Used for mtrr cleanup. It is spare mtrr entries number.
1537 Set to 2 or more if your graphical card needs more.
1539 n2= [NET] SDL Inc. RISCom/N2 synchronous serial card
1542 See header of drivers/scsi/NCR_D700.c.
1546 ncr53c400= [HW,SCSI]
1548 ncr53c400a= [HW,SCSI]
1550 ncr53c406a= [HW,SCSI]
1552 ncr53c8xx= [HW,SCSI]
1554 netdev= [NET] Network devices parameters
1555 Format: <irq>,<io>,<mem_start>,<mem_end>,<name>
1556 Note that mem_start is often overloaded to mean
1557 something different and driver-specific.
1558 This usage is only documented in each driver source
1562 [NETFILTER] Enable connection tracking flow accounting
1563 0 to disable accounting
1564 1 to enable accounting
1565 Default value depends on CONFIG_NF_CT_ACCT that is
1566 going to be removed in 2.6.29.
1569 See Documentation/filesystems/nfs/nfsroot.txt.
1571 nfsroot= [NFS] nfs root filesystem for disk-less boxes.
1572 See Documentation/filesystems/nfs/nfsroot.txt.
1574 nfs.callback_tcpport=
1575 [NFS] set the TCP port on which the NFSv4 callback
1576 channel should listen.
1579 [NFS] sets the pathname to the program which is used
1580 to update the NFS client cache entries.
1582 nfs.cache_getent_timeout=
1583 [NFS] sets the timeout after which an attempt to
1584 update a cache entry is deemed to have failed.
1586 nfs.idmap_cache_timeout=
1587 [NFS] set the maximum lifetime for idmapper cache
1591 [NFS] enable 64-bit inode numbers.
1592 If zero, the NFS client will fake up a 32-bit inode
1593 number for the readdir() and stat() syscalls instead
1594 of returning the full 64-bit number.
1595 The default is to return 64-bit inode numbers.
1597 nmi_debug= [KNL,AVR32,SH] Specify one or more actions to take
1598 when a NMI is triggered.
1599 Format: [state][,regs][,debounce][,die]
1601 nmi_watchdog= [KNL,BUGS=X86] Debugging features for SMP kernels
1602 Format: [panic,][num]
1604 0 - turn nmi_watchdog off
1605 1 - use the IO-APIC timer for the NMI watchdog
1606 2 - use the local APIC for the NMI watchdog using
1607 a performance counter. Note: This will use one
1608 performance counter and the local APIC's performance
1610 When panic is specified, panic when an NMI watchdog
1612 This is useful when you use a panic=... timeout and
1613 need the box quickly up again.
1614 Instead of 1 and 2 it is possible to use the following
1615 symbolic names: lapic and ioapic
1616 Example: nmi_watchdog=2 or nmi_watchdog=panic,lapic
1618 netpoll.carrier_timeout=
1619 [NET] Specifies amount of time (in seconds) that
1620 netpoll should wait for a carrier. By default netpoll
1623 no387 [BUGS=X86-32] Tells the kernel to use the 387 maths
1624 emulation library even if a 387 maths coprocessor
1628 [HW] Never suspend the console
1629 Disable suspending of consoles during suspend and
1630 hibernate operations. Once disabled, debugging
1631 messages can reach various consoles while the rest
1632 of the system is being put to sleep (ie, while
1633 debugging driver suspend/resume hooks). This may
1634 not work reliably with all consoles, but is known
1635 to work with serial and VGA consoles.
1637 noaliencache [MM, NUMA, SLAB] Disables the allocation of alien
1638 caches in the slab allocator. Saves per-node memory,
1639 but will impact performance.
1643 noapic [SMP,APIC] Tells the kernel to not make use of any
1644 IOAPICs that may be present in the system.
1646 nobats [PPC] Do not use BATs for mapping kernel lowmem
1647 on "Classic" PPC cores.
1651 noclflush [BUGS=X86] Don't use the CLFLUSH instruction
1653 nodelayacct [KNL] Disable per-task delay accounting
1655 nodisconnect [HW,SCSI,M68K] Disables SCSI disconnects.
1657 nodsp [SH] Disable hardware DSP at boot time.
1659 noefi [X86] Disable EFI runtime services support.
1664 On X86-32 available only on PAE configured kernels.
1665 noexec=on: enable non-executable mappings (default)
1666 noexec=off: disable non-executable mappings
1669 This affects only 32-bit executables.
1670 noexec32=on: enable non-executable mappings (default)
1671 read doesn't imply executable mappings
1672 noexec32=off: disable non-executable mappings
1673 read implies executable mappings
1675 nofpu [SH] Disable hardware FPU at boot time.
1677 nofxsr [BUGS=X86-32] Disables x86 floating point extended
1678 register save and restore. The kernel will only save
1679 legacy floating-point registers on task switch.
1681 noxsave [BUGS=X86] Disables x86 extended register state save
1682 and restore using xsave. The kernel will fallback to
1683 enabling legacy floating-point and sse state.
1685 nohlt [BUGS=ARM,SH] Tells the kernel that the sleep(SH) or
1686 wfi(ARM) instruction doesn't work correctly and not to
1687 use it. This is also useful when using JTAG debugger.
1689 no-hlt [BUGS=X86-32] Tells the kernel that the hlt
1690 instruction doesn't work correctly and not to
1693 no_file_caps Tells the kernel not to honor file capabilities. The
1694 only way then for a file to be executed with privilege
1695 is to be setuid root or executed by root.
1697 nohalt [IA-64] Tells the kernel not to use the power saving
1698 function PAL_HALT_LIGHT when idle. This increases
1699 power-consumption. On the positive side, it reduces
1700 interrupt wake-up latency, which may improve performance
1701 in certain environments such as networked servers or
1704 nohz= [KNL] Boottime enable/disable dynamic ticks
1705 Valid arguments: on, off
1708 noiotrap [SH] Disables trapped I/O port accesses.
1710 noirqdebug [X86-32] Disables the code which attempts to detect and
1711 disable unhandled interrupt sources.
1713 no_timer_check [X86,APIC] Disables the code which tests for
1714 broken timer IRQ sources.
1716 noisapnp [ISAPNP] Disables ISA PnP code.
1718 noinitrd [RAM] Tells the kernel not to load any configured
1721 nointremap [X86-64, Intel-IOMMU] Do not enable interrupt
1726 nojitter [IA64] Disables jitter checking for ITC timers.
1728 nolapic [X86-32,APIC] Do not enable or use the local APIC.
1730 nolapic_timer [X86-32,APIC] Do not use the local APIC timer.
1732 noltlbs [PPC] Do not use large page/tlb entries for kernel
1733 lowmem mapping on PPC40x.
1735 nomca [IA-64] Disable machine check abort handling
1737 nomce [X86-32] Machine Check Exception
1739 nomfgpt [X86-32] Disable Multi-Function General Purpose
1740 Timer usage (for AMD Geode machines).
1742 norandmaps Don't use address space randomization. Equivalent to
1743 echo 0 > /proc/sys/kernel/randomize_va_space
1745 noreplace-paravirt [X86-32,PV_OPS] Don't patch paravirt_ops
1747 noreplace-smp [X86-32,SMP] Don't replace SMP instructions
1748 with UP alternatives
1750 noresidual [PPC] Don't use residual data on PReP machines.
1752 noresume [SWSUSP] Disables resume and restores original swap
1755 no-scroll [VGA] Disables scrollback.
1756 This is required for the Braillex ib80-piezo Braille
1757 reader made by F.H. Papenmeier (Germany).
1761 nosep [BUGS=X86-32] Disables x86 SYSENTER/SYSEXIT support.
1763 nosmp [SMP] Tells an SMP kernel to act as a UP kernel,
1764 and disable the IO APIC. legacy for "maxcpus=0".
1766 nosoftlockup [KNL] Disable the soft-lockup detector.
1768 noswapaccount [KNL] Disable accounting of swap in memory resource
1769 controller. (See Documentation/cgroups/memory.txt)
1771 nosync [HW,M68K] Disables sync negotiation for all devices.
1773 notsc [BUGS=X86-32] Disable Time Stamp Counter
1775 nousb [USB] Disable the USB subsystem
1779 nox2apic [X86-64,APIC] Do not enable x2APIC mode.
1781 nptcg= [IA64] Override max number of concurrent global TLB
1782 purges which is reported from either PAL_VM_SUMMARY or
1785 nr_uarts= [SERIAL] maximum number of UARTs to be registered.
1787 numa_zonelist_order= [KNL, BOOT] Select zonelist order for NUMA.
1788 one of ['zone', 'node', 'default'] can be specified
1789 This can be set from sysctl after boot.
1790 See Documentation/sysctl/vm.txt for details.
1792 ohci1394_dma=early [HW] enable debugging via the ohci1394 driver.
1793 See Documentation/debugging-via-ohci1394.txt for more
1796 olpc_ec_timeout= [OLPC] ms delay when issuing EC commands
1797 Rather than timing out after 20 ms if an EC
1798 command is not properly ACKed, override the length
1799 of the timeout. We have interrupts disabled while
1800 waiting for the ACK, so if this is set too high
1801 interrupts *may* be lost!
1803 omap_mux= [OMAP] Override bootloader pin multiplexing.
1804 Format: <mux_mode0.mode_name=value>...
1805 For example, to override I2C bus2:
1806 omap_mux=i2c2_scl.i2c2_scl=0x100,i2c2_sda.i2c2_sda=0x100
1811 oprofile.timer= [HW]
1812 Use timer interrupt instead of performance counters
1814 oprofile.cpu_type= Force an oprofile cpu type
1815 This might be useful if you have an older oprofile
1816 userland or if you want common events.
1817 Format: { arch_perfmon }
1818 arch_perfmon: [X86] Force use of architectural
1819 perfmon on Intel CPUs instead of the
1820 CPU specific event set.
1822 osst= [HW,SCSI] SCSI Tape Driver
1823 Format: <buffer_size>,<write_threshold>
1824 See also Documentation/scsi/st.txt.
1826 panic= [KNL] Kernel behaviour on panic
1829 parkbd.port= [HW] Parallel port number the keyboard adapter is
1830 connected to, default is 0.
1832 parkbd.mode= [HW] Parallel port keyboard adapter mode of operation,
1833 0 for XT, 1 for AT (default is AT).
1836 parport= [HW,PPT] Specify parallel ports. 0 disables.
1837 Format: { 0 | auto | 0xBBB[,IRQ[,DMA]] }
1838 Use 'auto' to force the driver to use any
1839 IRQ/DMA settings detected (the default is to
1840 ignore detected IRQ/DMA settings because of
1841 possible conflicts). You can specify the base
1842 address, IRQ, and DMA settings; IRQ and DMA
1843 should be numbers, or 'auto' (for using detected
1844 settings on that particular port), or 'nofifo'
1845 (to avoid using a FIFO even if it is detected).
1846 Parallel ports are assigned in the order they
1847 are specified on the command line, starting
1850 parport_init_mode= [HW,PPT]
1851 Configure VIA parallel port to operate in
1852 a specific mode. This is necessary on Pegasos
1853 computer where firmware has no options for setting
1854 up parallel port mode and sets it to spp.
1855 Currently this function knows 686a and 8231 chips.
1856 Format: [spp|ps2|epp|ecp|ecpepp]
1858 pas2= [HW,OSS] Format:
1859 <io>,<irq>,<dma>,<dma16>,<sb_io>,<sb_irq>,<sb_dma>,<sb_dma16>
1862 See header of drivers/scsi/pas16.c.
1865 Halt all CPUs after the first oops has been printed for
1866 the specified number of seconds. This is to be used if
1867 your oopses keep scrolling off the screen.
1872 See header of drivers/block/paride/pcd.c.
1873 See also Documentation/blockdev/paride.txt.
1875 pci=option[,option...] [PCI] various PCI subsystem options:
1876 earlydump [X86] dump PCI config space before the kernel
1878 off [X86] don't probe for the PCI bus
1879 bios [X86-32] force use of PCI BIOS, don't access
1880 the hardware directly. Use this if your machine
1881 has a non-standard PCI host bridge.
1882 nobios [X86-32] disallow use of PCI BIOS, only direct
1883 hardware access methods are allowed. Use this
1884 if you experience crashes upon bootup and you
1885 suspect they are caused by the BIOS.
1886 conf1 [X86] Force use of PCI Configuration
1888 conf2 [X86] Force use of PCI Configuration
1890 noaer [PCIE] If the PCIEAER kernel config parameter is
1891 enabled, this kernel boot option can be used to
1892 disable the use of PCIE advanced error reporting.
1893 nodomains [PCI] Disable support for multiple PCI
1894 root domains (aka PCI segments, in ACPI-speak).
1895 nommconf [X86] Disable use of MMCONFIG for PCI
1897 check_enable_amd_mmconf [X86] check for and enable
1898 properly configured MMIO access to PCI
1899 config space on AMD family 10h CPU
1900 nomsi [MSI] If the PCI_MSI kernel config parameter is
1901 enabled, this kernel boot option can be used to
1902 disable the use of MSI interrupts system-wide.
1903 noioapicquirk [APIC] Disable all boot interrupt quirks.
1904 Safety option to keep boot IRQs enabled. This
1905 should never be necessary.
1906 ioapicreroute [APIC] Enable rerouting of boot IRQs to the
1907 primary IO-APIC for bridges that cannot disable
1908 boot IRQs. This fixes a source of spurious IRQs
1909 when the system masks IRQs.
1910 noioapicreroute [APIC] Disable workaround that uses the
1911 boot IRQ equivalent of an IRQ that connects to
1912 a chipset where boot IRQs cannot be disabled.
1913 The opposite of ioapicreroute.
1914 biosirq [X86-32] Use PCI BIOS calls to get the interrupt
1915 routing table. These calls are known to be buggy
1916 on several machines and they hang the machine
1917 when used, but on other computers it's the only
1918 way to get the interrupt routing table. Try
1919 this option if the kernel is unable to allocate
1920 IRQs or discover secondary PCI buses on your
1922 rom [X86] Assign address space to expansion ROMs.
1923 Use with caution as certain devices share
1924 address decoders between ROMs and other
1926 norom [X86] Do not assign address space to
1927 expansion ROMs that do not already have
1928 BIOS assigned address ranges.
1929 irqmask=0xMMMM [X86] Set a bit mask of IRQs allowed to be
1930 assigned automatically to PCI devices. You can
1931 make the kernel exclude IRQs of your ISA cards
1933 pirqaddr=0xAAAAA [X86] Specify the physical address
1934 of the PIRQ table (normally generated
1935 by the BIOS) if it is outside the
1936 F0000h-100000h range.
1937 lastbus=N [X86] Scan all buses thru bus #N. Can be
1938 useful if the kernel is unable to find your
1939 secondary buses and you want to tell it
1940 explicitly which ones they are.
1941 assign-busses [X86] Always assign all PCI bus
1942 numbers ourselves, overriding
1943 whatever the firmware may have done.
1944 usepirqmask [X86] Honor the possible IRQ mask stored
1945 in the BIOS $PIR table. This is needed on
1946 some systems with broken BIOSes, notably
1947 some HP Pavilion N5400 and Omnibook XE3
1948 notebooks. This will have no effect if ACPI
1949 IRQ routing is enabled.
1950 noacpi [X86] Do not use ACPI for IRQ routing
1951 or for PCI scanning.
1952 use_crs [X86] Use _CRS for PCI resource
1954 routeirq Do IRQ routing for all PCI devices.
1955 This is normally done in pci_enable_device(),
1956 so this option is a temporary workaround
1957 for broken drivers that don't call it.
1958 skip_isa_align [X86] do not align io start addr, so can
1959 handle more pci cards
1960 firmware [ARM] Do not re-enumerate the bus but instead
1961 just use the configuration from the
1962 bootloader. This is currently used on
1963 IXP2000 systems where the bus has to be
1964 configured a certain way for adjunct CPUs.
1965 noearly [X86] Don't do any early type 1 scanning.
1966 This might help on some broken boards which
1967 machine check when some devices' config space
1968 is read. But various workarounds are disabled
1969 and some IOMMU drivers will not work.
1970 bfsort Sort PCI devices into breadth-first order.
1971 This sorting is done to get a device
1972 order compatible with older (<= 2.4) kernels.
1973 nobfsort Don't sort PCI devices into breadth-first order.
1974 cbiosize=nn[KMG] The fixed amount of bus space which is
1975 reserved for the CardBus bridge's IO window.
1976 The default value is 256 bytes.
1977 cbmemsize=nn[KMG] The fixed amount of bus space which is
1978 reserved for the CardBus bridge's memory
1979 window. The default value is 64 megabytes.
1982 [<order of align>@][<domain>:]<bus>:<slot>.<func>[; ...]
1983 Specifies alignment and device to reassign
1984 aligned memory resources.
1985 If <order of align> is not specified,
1986 PAGE_SIZE is used as alignment.
1987 PCI-PCI bridge can be specified, if resource
1988 windows need to be expanded.
1989 ecrc= Enable/disable PCIe ECRC (transaction layer
1990 end-to-end CRC checking).
1991 bios: Use BIOS/firmware settings. This is the
1996 pcie_aspm= [PCIE] Forcibly enable or disable PCIe Active State Power
1999 force Enable ASPM even on devices that claim not to support it.
2000 WARNING: Forcing ASPM on may cause system lockups.
2002 pcmv= [HW,PCMCIA] BadgePAD 4
2005 See Documentation/blockdev/paride.txt.
2007 pdcchassis= [PARISC,HW] Disable/Enable PDC Chassis Status codes at
2010 See arch/parisc/kernel/pdc_chassis.c
2012 percpu_alloc= Select which percpu first chunk allocator to use.
2013 Currently supported values are "embed" and "page".
2014 Archs may support subset or none of the selections.
2015 See comments in mm/percpu.c for details on each
2016 allocator. This parameter is primarily for debugging
2017 and performance comparison.
2020 See Documentation/blockdev/paride.txt.
2023 See Documentation/blockdev/paride.txt.
2025 pirq= [SMP,APIC] Manual mp-table setup
2026 See Documentation/x86/i386/IO-APIC.txt.
2028 plip= [PPT,NET] Parallel port network link
2029 Format: { parport<nr> | timid | 0 }
2030 See also Documentation/parport.txt.
2032 pmtmr= [X86] Manual setup of pmtmr I/O Port.
2033 Override pmtimer IOPort with a hex value.
2037 Enable PNP debug messages. This depends on the
2038 CONFIG_PNP_DEBUG_MESSAGES option.
2044 { on | off | curr | res | no-curr | no-res }
2047 [ISAPNP] Exclude IRQs for the autoconfiguration
2050 [ISAPNP] Exclude DMAs for the autoconfiguration
2052 pnp_reserve_io= [ISAPNP] Exclude I/O ports for the autoconfiguration
2053 Ranges are in pairs (I/O port base and size).
2056 [ISAPNP] Exclude memory regions for the
2058 Ranges are in pairs (memory base and size).
2060 ports= [IP_VS_FTP] IPVS ftp helper module
2062 Up to 8 (IP_VS_APP_MAX_PORTS) ports
2064 Format: <port>,<port>....
2066 print-fatal-signals=
2067 [KNL] debug: print fatal signals
2069 If enabled, warn about various signal handling
2070 related application anomalies: too many signals,
2071 too many POSIX.1 timers, fatal signals causing a
2074 If you hit the warning due to signal overflow,
2075 you might want to try "ulimit -i unlimited".
2079 printk.time= Show timing data prefixed to each printk message line
2080 Format: <bool> (1/Y/y=enable, 0/N/n=disable)
2082 processor.max_cstate= [HW,ACPI]
2083 Limit processor to maximum C-state
2084 max_cstate=9 overrides any DMI blacklist limit.
2086 processor.nocst [HW,ACPI]
2087 Ignore the _CST method to determine C-states,
2088 instead using the legacy FADT method
2090 profile= [KNL] Enable kernel profiling via /proc/profile
2091 Format: [schedule,]<number>
2092 Param: "schedule" - profile schedule points.
2093 Param: <number> - step/bucket size as a power of 2 for
2094 statistical time based profiling.
2095 Param: "sleep" - profile D-state sleeping (millisecs).
2096 Requires CONFIG_SCHEDSTATS
2097 Param: "kvm" - profile VM exits.
2099 prompt_ramdisk= [RAM] List of RAM disks to prompt for floppy disk
2101 See Documentation/blockdev/ramdisk.txt.
2103 psmouse.proto= [HW,MOUSE] Highest PS2 mouse protocol extension to
2104 probe for; one of (bare|imps|exps|lifebook|any).
2105 psmouse.rate= [HW,MOUSE] Set desired mouse report rate, in reports
2107 psmouse.resetafter= [HW,MOUSE]
2108 Try to reset the device after so many bad packets
2111 [HW,MOUSE] Set desired mouse resolution, in dpi.
2112 psmouse.smartscroll=
2113 [HW,MOUSE] Controls Logitech smartscroll autorepeat.
2114 0 = disabled, 1 = enabled (default).
2116 pss= [HW,OSS] Personal Sound System (ECHO ESC614)
2118 <io>,<mss_io>,<mss_irq>,<mss_dma>,<mpu_io>,<mpu_irq>
2121 See Documentation/blockdev/paride.txt.
2124 [KNL] Number of legacy pty's. Overwrites compiled-in
2127 quiet [KNL] Disable most log messages
2132 See Documentation/md.txt.
2134 ramdisk_blocksize= [RAM]
2135 See Documentation/blockdev/ramdisk.txt.
2137 ramdisk_size= [RAM] Sizes of RAM disks in kilobytes
2138 See Documentation/blockdev/ramdisk.txt.
2140 rcupdate.blimit= [KNL,BOOT]
2141 Set maximum number of finished RCU callbacks to process
2144 rcupdate.qhimark= [KNL,BOOT]
2145 Set threshold of queued
2146 RCU callbacks over which batch limiting is disabled.
2148 rcupdate.qlowmark= [KNL,BOOT]
2149 Set threshold of queued RCU callbacks below which
2150 batch limiting is re-enabled.
2154 Run specified binary instead of /init from the ramdisk,
2155 used for early userspace startup. See initrd.
2157 reboot= [BUGS=X86-32,BUGS=ARM,BUGS=IA-64] Rebooting mode
2158 Format: <reboot_mode>[,<reboot_mode2>[,...]]
2159 See arch/*/kernel/reboot.c or arch/*/kernel/process.c
2162 [KNL, SMP] Set scheduler's default relax_domain_level.
2163 See Documentation/cgroups/cpusets.txt.
2165 reserve= [KNL,BUGS] Force the kernel to ignore some iomem area
2167 reservetop= [X86-32]
2169 Reserves a hole at the top of the kernel virtual
2172 reset_devices [KNL] Force drivers to reset the underlying device
2173 during initialization.
2176 Specify the partition device for software suspend
2178 resume_offset= [SWSUSP]
2179 Specify the offset from the beginning of the partition
2180 given by "resume=" at which the swap header is located,
2181 in <PAGE_SIZE> units (needed only for swap files).
2182 See Documentation/power/swsusp-and-swap-files.txt
2184 retain_initrd [RAM] Keep initrd memory after extraction
2186 rhash_entries= [KNL,NET]
2187 Set number of hash buckets for route cache
2189 riscom8= [HW,SERIAL]
2190 Format: <io_board1>[,<io_board2>[,...<io_boardN>]]
2192 ro [KNL] Mount root device read-only on boot
2194 root= [KNL] Root filesystem
2196 rootdelay= [KNL] Delay (in seconds) to pause before attempting to
2197 mount the root filesystem
2199 rootflags= [KNL] Set root filesystem mount option string
2201 rootfstype= [KNL] Set root filesystem type
2203 rootwait [KNL] Wait (indefinitely) for root device to show up.
2204 Useful for devices that are detected asynchronously
2205 (e.g. USB and MMC devices).
2207 rw [KNL] Mount root device read-write on boot
2209 S [KNL] Run init in single mode
2212 See drivers/net/irda/sa1100_ir.c.
2214 sbni= [NET] Granch SBNI12 leased line adapter
2216 sched_debug [KNL] Enables verbose scheduler debug messages.
2218 sc1200wdt= [HW,WDT] SC1200 WDT (watchdog) driver
2219 Format: <io>[,<timeout>[,<isapnp>]]
2221 scsi_debug_*= [SCSI]
2222 See drivers/scsi/scsi_debug.c.
2224 scsi_default_dev_flags=
2225 [SCSI] SCSI default device flags
2228 scsi_dev_flags= [SCSI] Black/white list entry for vendor and model
2229 Format: <vendor>:<model>:<flags>
2230 (flags are integer value)
2232 scsi_logging_level= [SCSI] a bit mask of logging levels
2233 See drivers/scsi/scsi_logging.h for bits. Also
2234 settable via sysctl at dev.scsi.logging_level
2235 (/proc/sys/dev/scsi/logging_level).
2236 There is also a nice 'scsi_logging_level' script in the
2237 S390-tools package, available for download at
2238 http://www-128.ibm.com/developerworks/linux/linux390/s390-tools-1.5.4.html
2240 scsi_mod.scan= [SCSI] sync (default) scans SCSI busses as they are
2241 discovered. async scans them in kernel threads,
2242 allowing boot to proceed. none ignores them, expecting
2243 user space to do the scan.
2245 security= [SECURITY] Choose a security module to enable at boot.
2246 If this boot parameter is not specified, only the first
2247 security module asking for security registration will be
2248 loaded. An invalid security module name will be treated
2249 as if no module has been chosen.
2251 selinux= [SELINUX] Disable or enable SELinux at boot time.
2252 Format: { "0" | "1" }
2253 See security/selinux/Kconfig help text.
2256 Default value is set via kernel config option.
2257 If enabled at boot time, /selinux/disable can be used
2258 later to disable prior to initial policy load.
2260 serialnumber [BUGS=X86-32]
2263 Maximal number of shapers.
2265 show_msr= [x86] show boot-time MSR settings
2266 Format: { <integer> }
2267 Show boot-time (BIOS-initialized) MSR settings.
2268 The parameter means the number of CPUs to show,
2269 for example 1 means boot CPU only.
2272 See header of drivers/scsi/sim710.c.
2279 slub_debug[=options[,slabs]] [MM, SLUB]
2280 Enabling slub_debug allows one to determine the
2281 culprit if slab objects become corrupted. Enabling
2282 slub_debug can create guard zones around objects and
2283 may poison objects when not in use. Also tracks the
2284 last alloc / free. For more information see
2285 Documentation/vm/slub.txt.
2287 slub_max_order= [MM, SLUB]
2288 Determines the maximum allowed order for slabs.
2289 A high setting may cause OOMs due to memory
2290 fragmentation. For more information see
2291 Documentation/vm/slub.txt.
2293 slub_min_objects= [MM, SLUB]
2294 The minimum number of objects per slab. SLUB will
2295 increase the slab order up to slub_max_order to
2296 generate a sufficiently large slab able to contain
2297 the number of objects indicated. The higher the number
2298 of objects the smaller the overhead of tracking slabs
2299 and the less frequently locks need to be acquired.
2300 For more information see Documentation/vm/slub.txt.
2302 slub_min_order= [MM, SLUB]
2303 Determines the mininum page order for slabs. Must be
2304 lower than slub_max_order.
2305 For more information see Documentation/vm/slub.txt.
2307 slub_nomerge [MM, SLUB]
2308 Disable merging of slabs with similar size. May be
2309 necessary if there is some reason to distinguish
2310 allocs to different slabs. Debug options disable
2311 merging on their own.
2312 For more information see Documentation/vm/slub.txt.
2315 Format: <io1>[,<io2>[,...,<io8>]]
2317 smp-alt-once [X86-32,SMP] On a hotplug CPU system, only
2318 attempt to substitute SMP alternatives once at boot.
2320 smsc-ircc2.nopnp [HW] Don't use PNP to discover SMC devices
2321 smsc-ircc2.ircc_cfg= [HW] Device configuration I/O port
2322 smsc-ircc2.ircc_sir= [HW] SIR base I/O port
2323 smsc-ircc2.ircc_fir= [HW] FIR base I/O port
2324 smsc-ircc2.ircc_irq= [HW] IRQ line
2325 smsc-ircc2.ircc_dma= [HW] DMA channel
2326 smsc-ircc2.ircc_transceiver= [HW] Transceiver type:
2327 0: Toshiba Satellite 1800 (GP data pin select)
2328 1: Fast pin select (default)
2331 snd-ad1816a= [HW,ALSA]
2333 snd-ad1848= [HW,ALSA]
2335 snd-ali5451= [HW,ALSA]
2337 snd-als100= [HW,ALSA]
2339 snd-als4000= [HW,ALSA]
2341 snd-azt2320= [HW,ALSA]
2343 snd-cmi8330= [HW,ALSA]
2345 snd-cmipci= [HW,ALSA]
2347 snd-cs4231= [HW,ALSA]
2349 snd-cs4232= [HW,ALSA]
2351 snd-cs4236= [HW,ALSA]
2353 snd-cs4281= [HW,ALSA]
2355 snd-cs46xx= [HW,ALSA]
2357 snd-dt019x= [HW,ALSA]
2359 snd-dummy= [HW,ALSA]
2361 snd-emu10k1= [HW,ALSA]
2363 snd-ens1370= [HW,ALSA]
2365 snd-ens1371= [HW,ALSA]
2367 snd-es968= [HW,ALSA]
2369 snd-es1688= [HW,ALSA]
2371 snd-es18xx= [HW,ALSA]
2373 snd-es1938= [HW,ALSA]
2375 snd-es1968= [HW,ALSA]
2377 snd-fm801= [HW,ALSA]
2379 snd-gusclassic= [HW,ALSA]
2381 snd-gusextreme= [HW,ALSA]
2383 snd-gusmax= [HW,ALSA]
2387 snd-ice1712= [HW,ALSA]
2389 snd-intel8x0= [HW,ALSA]
2391 snd-interwave= [HW,ALSA]
2396 snd-korg1212= [HW,ALSA]
2398 snd-maestro3= [HW,ALSA]
2400 snd-mpu401= [HW,ALSA]
2402 snd-mtpav= [HW,ALSA]
2404 snd-nm256= [HW,ALSA]
2406 snd-opl3sa2= [HW,ALSA]
2414 snd-opti93x= [HW,ALSA]
2418 snd-rme32= [HW,ALSA]
2420 snd-rme96= [HW,ALSA]
2422 snd-rme9652= [HW,ALSA]
2428 snd-sbawe= [HW,ALSA]
2430 snd-serial= [HW,ALSA]
2432 snd-sgalaxy= [HW,ALSA]
2434 snd-sonicvibes= [HW,ALSA]
2439 snd-sun-cs4231= [HW,ALSA]
2441 snd-trident= [HW,ALSA]
2443 snd-usb-audio= [HW,ALSA,USB]
2445 snd-via82xx= [HW,ALSA]
2447 snd-virmidi= [HW,ALSA]
2449 snd-wavefront= [HW,ALSA]
2451 snd-ymfpci= [HW,ALSA]
2454 [KNL] Should the soft-lockup detector generate panics.
2456 sonypi.*= [HW] Sony Programmable I/O Control Device driver
2457 See Documentation/sonypi.txt
2459 specialix= [HW,SERIAL] Specialix multi-serial port adapter
2460 See Documentation/serial/specialix.txt.
2462 spia_io_base= [HW,MTD]
2468 Format: <io>,<irq>,<dma>,<mpu_io>,<mpu_irq>
2470 st= [HW,SCSI] SCSI tape parameters (buffers, etc.)
2471 See Documentation/scsi/st.txt.
2474 Enabled the stack tracer on boot up.
2478 Set the STI (builtin display/keyboard on the HP-PARISC
2479 machines) console (graphic card) which should be used
2480 as the initial boot-console.
2481 See also comment in drivers/video/console/sticore.c.
2484 See comment in drivers/video/console/sticore.c.
2487 Format: bpp:<bpp1>[:<bpp2>[:<bpp3>...]]
2489 sunrpc.min_resvport=
2490 sunrpc.max_resvport=
2492 SunRPC servers often require that client requests
2493 originate from a privileged port (i.e. a port in the
2494 range 0 < portnr < 1024).
2495 An administrator who wishes to reserve some of these
2496 ports for other uses may adjust the range that the
2497 kernel's sunrpc client considers to be privileged
2498 using these two parameters to set the minimum and
2499 maximum port values.
2503 Control how the NFS server code allocates CPUs to
2504 service thread pools. Depending on how many NICs
2505 you have and where their interrupts are bound, this
2506 option will affect which CPUs will do NFS serving.
2507 Note: this parameter cannot be changed while the
2508 NFS server is running.
2510 auto the server chooses an appropriate mode
2511 automatically using heuristics
2512 global a single global pool contains all CPUs
2513 percpu one pool for each CPU
2514 pernode one pool for each NUMA node (equivalent
2515 to global on non-NUMA machines)
2517 sunrpc.tcp_slot_table_entries=
2518 sunrpc.udp_slot_table_entries=
2520 Sets the upper limit on the number of simultaneous
2521 RPC calls that can be sent from the client to a
2522 server. Increasing these values may allow you to
2523 improve throughput, but will also increase the
2524 amount of memory reserved for use by the client.
2526 swiotlb= [IA-64] Number of I/O TLB slabs
2530 sym53c416= [HW,SCSI]
2531 See header of drivers/scsi/sym53c416.c.
2533 sysrq_always_enabled
2535 Ignore sysrq setting - this boot parameter will
2536 neutralize any effect of /proc/sys/kernel/sysrq.
2537 Useful for debugging.
2540 See header of drivers/scsi/t128.c.
2544 test_suspend= [SUSPEND]
2545 Specify "mem" (for Suspend-to-RAM) or "standby" (for
2546 standby suspend) as the system sleep state to briefly
2547 enter during system startup. The system is woken from
2548 this state using a wakeup-capable RTC alarm.
2550 thash_entries= [KNL,NET]
2551 Set number of hash buckets for TCP connection
2553 thermal.act= [HW,ACPI]
2554 -1: disable all active trip points in all thermal zones
2555 <degrees C>: override all lowest active trip points
2557 thermal.crt= [HW,ACPI]
2558 -1: disable all critical trip points in all thermal zones
2559 <degrees C>: override all critical trip points
2561 thermal.nocrt= [HW,ACPI]
2562 Set to disable actions on ACPI thermal zone
2563 critical and hot trip points.
2565 thermal.off= [HW,ACPI]
2566 1: disable ACPI thermal control
2568 thermal.psv= [HW,ACPI]
2569 -1: disable all passive trip points
2570 <degrees C>: override all passive trip points to this
2573 thermal.tzp= [HW,ACPI]
2574 Specify global default ACPI thermal zone polling rate
2575 <deci-seconds>: poll all this frequency
2576 0: no polling (default)
2579 See comment before function dc390_setup() in
2580 drivers/scsi/tmscsim.c.
2584 Specify if the kernel should make use of the cpu
2585 topology informations if the hardware supports these.
2586 The scheduler will make use of these informations and
2587 e.g. base its process migration decisions on it.
2592 trace_buf_size=nn[KMG]
2593 [FTRACE] will set tracing buffer size.
2595 trace_event=[event-list]
2596 [FTRACE] Set and start specified trace events in order
2597 to facilitate early boot debugging.
2598 See also Documentation/trace/events.txt
2600 trix= [HW,OSS] MediaTrix AudioTrix Pro
2602 <io>,<irq>,<dma>,<dma2>,<sb_io>,<sb_irq>,<sb_dma>,<mpu_io>,<mpu_irq>
2604 tsc= Disable clocksource-must-verify flag for TSC.
2606 [x86] reliable: mark tsc clocksource as reliable, this
2607 disables clocksource verification at runtime.
2608 Used to enable high-resolution timer mode on older
2609 hardware, and in virtualized environment.
2611 turbografx.map[2|3]= [HW,JOY]
2612 TurboGraFX parallel port interface
2614 <port#>,<js1>,<js2>,<js3>,<js4>,<js5>,<js6>,<js7>
2615 See also Documentation/input/joystick-parport.txt
2617 u14-34f= [HW,SCSI] UltraStor 14F/34F SCSI host adapter
2618 See header of drivers/scsi/u14-34f.c.
2626 uhash_entries= [KNL,NET]
2627 Set number of hash buckets for UDP/UDP-Lite connections
2630 [USB] Ignore overcurrent events (default N).
2631 Some badly-designed motherboards generate lots of
2632 bogus events, for ports that aren't wired to
2633 anything. Set this parameter to avoid log spamming.
2634 Note that genuine overcurrent events won't be
2639 Set unknown_nmi_panic=1 early on boot.
2641 usbcore.autosuspend=
2642 [USB] The autosuspend time delay (in seconds) used
2643 for newly-detected USB devices (default 2). This
2644 is the time required before an idle device will be
2645 autosuspended. Devices for which the delay is set
2646 to a negative value won't be autosuspended at all.
2648 usbcore.usbfs_snoop=
2649 [USB] Set to log all usbfs traffic (default 0 = off).
2651 usbcore.blinkenlights=
2652 [USB] Set to cycle leds on hubs (default 0 = off).
2654 usbcore.old_scheme_first=
2655 [USB] Start with the old device initialization
2656 scheme (default 0 = off).
2658 usbcore.use_both_schemes=
2659 [USB] Try the other device initialization scheme
2660 if the first one fails (default 1 = enabled).
2662 usbcore.initial_descriptor_timeout=
2663 [USB] Specifies timeout for the initial 64-byte
2664 USB_REQ_GET_DESCRIPTOR request in milliseconds
2665 (default 5000 = 5.0 seconds).
2668 [USBHID] The interval which mice are to be polled at.
2670 usb-storage.delay_use=
2671 [UMS] The delay in seconds before a new device is
2672 scanned for Logical Units (default 5).
2675 [UMS] A list of quirks entries to supplement or
2676 override the built-in unusual_devs list. List
2677 entries are separated by commas. Each entry has
2678 the form VID:PID:Flags where VID and PID are Vendor
2679 and Product ID values (4-digit hex numbers) and
2680 Flags is a set of characters, each corresponding
2681 to a common usb-storage quirk flag as follows:
2682 a = SANE_SENSE (collect more than 18 bytes
2684 b = BAD_SENSE (don't collect more than 18
2685 bytes of sense data);
2686 c = FIX_CAPACITY (decrease the reported
2687 device capacity by one sector);
2688 h = CAPACITY_HEURISTICS (decrease the
2689 reported device capacity by one
2690 sector if the number is odd);
2691 i = IGNORE_DEVICE (don't bind to this
2693 l = NOT_LOCKABLE (don't try to lock and
2694 unlock ejectable media);
2695 m = MAX_SECTORS_64 (don't transfer more
2696 than 64 sectors = 32 KB at a time);
2697 o = CAPACITY_OK (accept the capacity
2698 reported by the device);
2699 r = IGNORE_RESIDUE (the device reports
2700 bogus residue values);
2701 s = SINGLE_LUN (the device has only one
2703 w = NO_WP_DETECT (don't test whether the
2704 medium is write-protected).
2705 Example: quirks=0419:aaf5:rl,0421:0433:rc
2708 vdso=2: enable compat VDSO (default with COMPAT_VDSO)
2709 vdso=1: enable VDSO (default)
2710 vdso=0: disable VDSO mapping
2713 vdso32=2: enable compat VDSO (default with COMPAT_VDSO)
2714 vdso32=1: enable 32-bit VDSO (default)
2715 vdso32=0: disable 32-bit VDSO mapping
2718 vector=percpu: enable percpu vector domain
2720 video= [FB] Frame buffer configuration
2721 See Documentation/fb/modedb.txt.
2723 vga= [BOOT,X86-32] Select a particular video mode
2724 See Documentation/x86/boot.txt and
2725 Documentation/svga.txt.
2726 Use vga=ask for menu.
2727 This is actually a boot loader parameter; the value is
2728 passed to the kernel using a special protocol.
2730 vmalloc=nn[KMG] [KNL,BOOT] Forces the vmalloc area to have an exact
2731 size of <nn>. This can be used to increase the
2732 minimum size (128MB on x86). It can also be used to
2733 decrease the size and leave more room for directly
2736 vmhalt= [KNL,S390] Perform z/VM CP command after system halt.
2739 vmpanic= [KNL,S390] Perform z/VM CP command after kernel panic.
2742 vmpoff= [KNL,S390] Perform z/VM CP command after power off.
2745 vt.cur_default= [VT] Default cursor shape.
2746 Format: 0xCCBBAA, where AA, BB, and CC are the same as
2747 the parameters of the <Esc>[?A;B;Cc escape sequence;
2748 see VGA-softcursor.txt. Default: 2 = underline.
2750 vt.default_blu= [VT]
2751 Format: <blue0>,<blue1>,<blue2>,...,<blue15>
2752 Change the default blue palette of the console.
2753 This is a 16-member array composed of values
2756 vt.default_grn= [VT]
2757 Format: <green0>,<green1>,<green2>,...,<green15>
2758 Change the default green palette of the console.
2759 This is a 16-member array composed of values
2762 vt.default_red= [VT]
2763 Format: <red0>,<red1>,<red2>,...,<red15>
2764 Change the default red palette of the console.
2765 This is a 16-member array composed of values
2771 Set system-wide default UTF-8 mode for all tty's.
2772 Default is 1, i.e. UTF-8 mode is enabled for all
2773 newly opened terminals.
2775 vt.global_cursor_default=
2778 Set system-wide default for whether a cursor
2779 is shown on new VTs. Default is -1,
2780 i.e. cursors will be created by default unless
2781 overridden by individual drivers. 0 will hide
2782 cursors, 1 will display them.
2784 waveartist= [HW,OSS]
2785 Format: <io>,<irq>,<dma>,<dma2>
2788 See header of drivers/scsi/wd33c93.c.
2791 See header of drivers/scsi/wd7000.c.
2794 See Documentation/watchdog/wdt.txt.
2796 x2apic_phys [X86-64,APIC] Use x2apic physical mode instead of
2797 default x2apic cluster mode on platforms
2800 xd= [HW,XT] Original XT pre-IDE (RLL encoded) disks.
2801 xd_geo= See header of drivers/block/xd.c.
2803 xirc2ps_cs= [NET,PCMCIA]
2805 <irq>,<irq_mask>,<io>,<full_duplex>,<do_sound>,<lockup_hack>[,<irq2>[,<irq3>[,<irq4>]]]
2807 ______________________________________________________________________
2811 Add documentation for ALSA options.
2812 Add more DRM drivers.
git://ftp.safe.ca / safe / jmp / linux-2.6 / blob