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 ARM ARM architecture is enabled.
44 AVR32 AVR32 architecture is enabled.
45 AX25 Appropriate AX.25 support is enabled.
46 BLACKFIN Blackfin architecture is enabled.
47 DRM Direct Rendering Management support is enabled.
48 DYNAMIC_DEBUG Build in debug messages and enable them at runtime
49 EDD BIOS Enhanced Disk Drive Services (EDD) is enabled
50 EFI EFI Partitioning (GPT) is enabled
51 EIDE EIDE/ATAPI support is enabled.
52 EVM Extended Verification Module
53 FB The frame buffer device is enabled.
54 FTRACE Function tracing enabled.
55 GCOV GCOV profiling is enabled.
56 HW Appropriate hardware is enabled.
57 IA-64 IA-64 architecture is enabled.
58 IMA Integrity measurement architecture is enabled.
59 IOSCHED More than one I/O scheduler is enabled.
60 IP_PNP IP DHCP, BOOTP, or RARP is enabled.
61 IPV6 IPv6 support is enabled.
62 ISAPNP ISA PnP code is enabled.
63 ISDN Appropriate ISDN support is enabled.
64 JOY Appropriate joystick support is enabled.
65 KGDB Kernel debugger support is enabled.
66 KVM Kernel Virtual Machine support is enabled.
67 LIBATA Libata driver is enabled
68 LP Printer support is enabled.
69 LOOP Loopback device support is enabled.
70 M68k M68k architecture is enabled.
71 These options have more detailed description inside of
72 Documentation/m68k/kernel-options.txt.
73 MCA MCA bus support is enabled.
74 MDA MDA console support is enabled.
75 MIPS MIPS architecture is enabled.
76 MOUSE Appropriate mouse support is enabled.
77 MSI Message Signaled Interrupts (PCI).
78 MTD MTD (Memory Technology Device) support is enabled.
79 NET Appropriate network support is enabled.
80 NUMA NUMA support is enabled.
81 NFS Appropriate NFS support is enabled.
82 OSS OSS sound support is enabled.
83 PV_OPS A paravirtualized kernel is enabled.
84 PARIDE The ParIDE (parallel port IDE) subsystem is enabled.
85 PARISC The PA-RISC architecture is enabled.
86 PCI PCI bus support is enabled.
87 PCIE PCI Express support is enabled.
88 PCMCIA The PCMCIA subsystem is enabled.
89 PNP Plug & Play support is enabled.
90 PPC PowerPC architecture is enabled.
91 PPT Parallel port support is enabled.
92 PS2 Appropriate PS/2 support is enabled.
93 RAM RAM disk support is enabled.
94 S390 S390 architecture is enabled.
95 SCSI Appropriate SCSI support is enabled.
96 A lot of drivers have their options described inside
97 the Documentation/scsi/ sub-directory.
98 SECURITY Different security models are enabled.
99 SELINUX SELinux support is enabled.
100 APPARMOR AppArmor support is enabled.
101 SERIAL Serial support is enabled.
102 SH SuperH architecture is enabled.
103 SMP The kernel is an SMP kernel.
104 SPARC Sparc architecture is enabled.
105 SWSUSP Software suspend (hibernation) is enabled.
106 SUSPEND System suspend states are enabled.
107 TPM TPM drivers are enabled.
108 TS Appropriate touchscreen support is enabled.
109 UMS USB Mass Storage support is enabled.
110 USB USB support is enabled.
111 USBHID USB Human Interface Device support is enabled.
112 V4L Video For Linux support is enabled.
113 VGA The VGA console has been enabled.
114 VT Virtual terminal support is enabled.
115 WDT Watchdog support is enabled.
116 XT IBM PC/XT MFM hard disk support is enabled.
117 X86-32 X86-32, aka i386 architecture is enabled.
118 X86-64 X86-64 architecture is enabled.
119 More X86-64 boot options can be found in
120 Documentation/x86/x86_64/boot-options.txt .
121 X86 Either 32-bit or 64-bit x86 (same as X86-32+X86-64)
122 XEN Xen support is enabled
124 In addition, the following text indicates that the option:
126 BUGS= Relates to possible processor bugs on the said processor.
127 KNL Is a kernel start-up parameter.
128 BOOT Is a boot loader parameter.
130 Parameters denoted with BOOT are actually interpreted by the boot
131 loader, and have no meaning to the kernel directly.
132 Do not modify the syntax of boot loader parameters without extreme
133 need or coordination with <Documentation/x86/boot.txt>.
135 There are also arch-specific kernel-parameters not documented here.
136 See for example <Documentation/x86/x86_64/boot-options.txt>.
138 Note that ALL kernel parameters listed below are CASE SENSITIVE, and that
139 a trailing = on the name of any parameter states that that parameter will
140 be entered as an environment variable, whereas its absence indicates that
141 it will appear as a kernel argument readable via /proc/cmdline by programs
142 running once the system is up.
144 The number of kernel parameters is not limited, but the length of the
145 complete command line (parameters including spaces etc.) is limited to
146 a fixed number of characters. This limit depends on the architecture
147 and is between 256 and 4096 characters. It is defined in the file
148 ./include/asm/setup.h as COMMAND_LINE_SIZE.
150 Finally, the [KMG] suffix is commonly described after a number of kernel
151 parameter values. These 'K', 'M', and 'G' letters represent the _binary_
152 multipliers 'Kilo', 'Mega', and 'Giga', equalling 2^10, 2^20, and 2^30
153 bytes respectively. Such letter suffixes can also be entirely omitted.
157 Advanced Configuration and Power Interface
158 Format: { force | off | strict | noirq | rsdt }
159 force -- enable ACPI if default was off
160 off -- disable ACPI if default was on
161 noirq -- do not use ACPI for IRQ routing
162 strict -- Be less tolerant of platforms that are not
163 strictly ACPI specification compliant.
164 rsdt -- prefer RSDT over (default) XSDT
165 copy_dsdt -- copy DSDT to memory
167 See also Documentation/power/runtime_pm.txt, pci=noacpi
169 acpi_rsdp= [ACPI,EFI,KEXEC]
170 Pass the RSDP address to the kernel, mostly used
171 on machines running EFI runtime service to boot the
172 second kernel for kdump.
174 acpi_apic_instance= [ACPI, IOAPIC]
176 2: use 2nd APIC table, if available
177 1,0: use 1st APIC table
180 acpi_backlight= [HW,ACPI]
181 acpi_backlight=vendor
183 If set to vendor, prefer vendor specific driver
184 (e.g. thinkpad_acpi, sony_acpi, etc.) instead
185 of the ACPI video.ko driver.
187 acpi.debug_layer= [HW,ACPI,ACPI_DEBUG]
188 acpi.debug_level= [HW,ACPI,ACPI_DEBUG]
190 CONFIG_ACPI_DEBUG must be enabled to produce any ACPI
191 debug output. Bits in debug_layer correspond to a
192 _COMPONENT in an ACPI source file, e.g.,
193 #define _COMPONENT ACPI_PCI_COMPONENT
194 Bits in debug_level correspond to a level in
195 ACPI_DEBUG_PRINT statements, e.g.,
196 ACPI_DEBUG_PRINT((ACPI_DB_INFO, ...
197 The debug_level mask defaults to "info". See
198 Documentation/acpi/debug.txt for more information about
199 debug layers and levels.
201 Enable processor driver info messages:
202 acpi.debug_layer=0x20000000
203 Enable PCI/PCI interrupt routing info messages:
204 acpi.debug_layer=0x400000
205 Enable AML "Debug" output, i.e., stores to the Debug
206 object while interpreting AML:
207 acpi.debug_layer=0xffffffff acpi.debug_level=0x2
208 Enable all messages related to ACPI hardware:
209 acpi.debug_layer=0x2 acpi.debug_level=0xffffffff
211 Some values produce so much output that the system is
212 unusable. The "log_buf_len" parameter may be useful
213 if you need to capture more output.
215 acpi_irq_balance [HW,ACPI]
216 ACPI will balance active IRQs
219 acpi_irq_nobalance [HW,ACPI]
220 ACPI will not move active IRQs (default)
223 acpi_irq_isa= [HW,ACPI] If irq_balance, mark listed IRQs used by ISA
224 Format: <irq>,<irq>...
226 acpi_irq_pci= [HW,ACPI] If irq_balance, clear listed IRQs for
228 Format: <irq>,<irq>...
230 acpi_no_auto_ssdt [HW,ACPI] Disable automatic loading of SSDT
232 acpi_os_name= [HW,ACPI] Tell ACPI BIOS the name of the OS
233 Format: To spoof as Windows 98: ="Microsoft Windows"
235 acpi_osi= [HW,ACPI] Modify list of supported OS interface strings
236 acpi_osi="string1" # add string1 -- only one string
237 acpi_osi="!string2" # remove built-in string2
238 acpi_osi= # disable all strings
241 Override the pmtimer bug detection: force the kernel
242 to assume that this machine's pmtimer latches its value
243 and always returns good values.
245 acpi_sci= [HW,ACPI] ACPI System Control Interrupt trigger mode
246 Format: { level | edge | high | low }
248 acpi_serialize [HW,ACPI] force serialization of AML methods
250 acpi_skip_timer_override [HW,ACPI]
251 Recognize and ignore IRQ0/pin2 Interrupt Override.
252 For broken nForce2 BIOS resulting in XT-PIC timer.
254 acpi_sleep= [HW,ACPI] Sleep options
255 Format: { s3_bios, s3_mode, s3_beep, s3_leds, s4_nohwsig,
256 old_ordering, nonvs, sci_force_enable }
257 See Documentation/power/video.txt for information on
259 s3_beep is for debugging; it makes the PC's speaker beep
260 as soon as the kernel's real-mode entry point is called.
261 s3_leds is for debugging; it flashes the keyboard LEDs
262 3 times as soon as the kernel's real-mode entry point is
264 s4_nohwsig prevents ACPI hardware signature from being
265 used during resume from hibernation.
266 old_ordering causes the ACPI 1.0 ordering of the _PTS
267 control method, with respect to putting devices into
268 low power states, to be enforced (the ACPI 2.0 ordering
269 of _PTS is used by default).
270 nonvs prevents the kernel from saving/restoring the
271 ACPI NVS memory during suspend/hibernation and resume.
272 sci_force_enable causes the kernel to set SCI_EN directly
273 on resume from S1/S3 (which is against the ACPI spec,
274 but some broken systems don't work without it).
276 acpi_use_timer_override [HW,ACPI]
277 Use timer override. For some broken Nvidia NF5 boards
278 that require a timer override, but don't have HPET
280 acpi_enforce_resources= [ACPI]
281 { strict | lax | no }
282 Check for resource conflicts between native drivers
283 and ACPI OperationRegions (SystemIO and SystemMemory
284 only). IO ports and memory declared in ACPI might be
285 used by the ACPI subsystem in arbitrary AML code and
286 can interfere with legacy drivers.
287 strict (default): access to resources claimed by ACPI
288 is denied; legacy drivers trying to access reserved
289 resources will fail to bind to device using them.
290 lax: access to resources claimed by ACPI is allowed;
291 legacy drivers trying to access reserved resources
292 will bind successfully but a warning message is logged.
293 no: ACPI OperationRegions are not marked as reserved,
294 no further checks are performed.
296 add_efi_memmap [EFI; X86] Include EFI memory map in
297 kernel's map of available physical RAM.
300 { off | try_unsupported }
301 off: disable AGP support
302 try_unsupported: try to drive unsupported chipsets
303 (may crash computer or cause data corruption)
306 See Documentation/sound/alsa/alsa-parameters.txt
309 Allow the default userspace alignment fault handler
310 behaviour to be specified. Bit 0 enables warnings,
311 bit 1 enables fixups, and bit 2 sends a segfault.
313 align_va_addr= [X86-64]
314 Align virtual addresses by clearing slice [14:12] when
315 allocating a VMA at process creation time. This option
316 gives you up to 3% performance improvement on AMD F15h
317 machines (where it is enabled by default) for a
318 CPU-intensive style benchmark, and it can vary highly in
319 a microbenchmark depending on workload and compiler.
321 32: only for 32-bit processes
322 64: only for 64-bit processes
323 on: enable for both 32- and 64-bit processes
324 off: disable for both 32- and 64-bit processes
326 amd_iommu= [HW,X86-64]
327 Pass parameters to the AMD IOMMU driver in the system.
329 fullflush - enable flushing of IO/TLB entries when
330 they are unmapped. Otherwise they are
331 flushed before they will be reused, which
333 off - do not initialize any AMD IOMMU found in
336 amijoy.map= [HW,JOY] Amiga joystick support
337 Map of devices attached to JOY0DAT and JOY1DAT
339 See also Documentation/input/joystick.txt
341 analog.map= [HW,JOY] Analog joystick and gamepad support
342 Specifies type or capabilities of an analog joystick
343 connected to one of 16 gameports
344 Format: <type1>,<type2>,..<type16>
347 Power management functions (SPARCstation-4/5 + deriv.)
349 Disable APC CPU standby support. SPARCstation-Fox does
350 not play well with APC CPU idle - disable it if you have
351 APC and your system crashes randomly.
353 apic= [APIC,X86-32] Advanced Programmable Interrupt Controller
354 Change the output verbosity whilst booting
355 Format: { quiet (default) | verbose | debug }
356 Change the amount of debugging information output
357 when initialising the APIC and IO-APIC components.
360 See Documentation/networking/ipv6.txt.
362 show_lapic= [APIC,X86] Advanced Programmable Interrupt Controller
363 Limit apic dumping. The parameter defines the maximal
364 number of local apics being dumped. Also it is possible
365 to set it to "all" by meaning -- no limit here.
366 Format: { 1 (default) | 2 | ... | all }.
367 The parameter valid if only apic=debug or
368 apic=verbose is specified.
369 Example: apic=debug show_lapic=all
371 apm= [APM] Advanced Power Management
372 See header of arch/x86/kernel/apm_32.c.
374 arcrimi= [HW,NET] ARCnet - "RIM I" (entirely mem-mapped) cards
375 Format: <io>,<irq>,<nodeID>
379 atarimouse= [HW,MOUSE] Atari Mouse
381 atkbd.extra= [HW] Enable extra LEDs and keys on IBM RapidAccess,
382 EzKey and similar keyboards
384 atkbd.reset= [HW] Reset keyboard during initialization
386 atkbd.set= [HW] Select keyboard code set
387 Format: <int> (2 = AT (default), 3 = PS/2)
389 atkbd.scroll= [HW] Enable scroll wheel on MS Office and similar
392 atkbd.softraw= [HW] Choose between synthetic and real raw mode
393 Format: <bool> (0 = real, 1 = synthetic (default))
395 atkbd.softrepeat= [HW]
396 Use software keyboard repeat
400 baycom_epp= [HW,AX25]
403 baycom_par= [HW,AX25] BayCom Parallel Port AX.25 Modem
405 See header of drivers/net/hamradio/baycom_par.c.
407 baycom_ser_fdx= [HW,AX25]
408 BayCom Serial Port AX.25 Modem (Full Duplex Mode)
409 Format: <io>,<irq>,<mode>[,<baud>]
410 See header of drivers/net/hamradio/baycom_ser_fdx.c.
412 baycom_ser_hdx= [HW,AX25]
413 BayCom Serial Port AX.25 Modem (Half Duplex Mode)
414 Format: <io>,<irq>,<mode>
415 See header of drivers/net/hamradio/baycom_ser_hdx.c.
417 boot_delay= Milliseconds to delay each printk during boot.
418 Values larger than 10 seconds (10000) are changed to
422 bootmem_debug [KNL] Enable bootmem allocator debug messages.
424 bttv.card= [HW,V4L] bttv (bt848 + bt878 based grabber cards)
425 bttv.radio= Most important insmod options are available as
427 bttv.pll= See Documentation/video4linux/bttv/Insmod-options
430 bulk_remove=off [PPC] This parameter disables the use of the pSeries
431 firmware feature for flushing multiple hpte entries
434 c101= [NET] Moxa C101 synchronous serial card
436 cachesize= [BUGS=X86-32] Override level 2 CPU cache size detection.
437 Sometimes CPU hardware bugs make them report the cache
438 size incorrectly. The kernel will attempt work arounds
439 to fix known problems, but for some CPUs it is not
440 possible to determine what the correct size should be.
441 This option provides an override for these situations.
444 [SECURITY] Disable capabilities. This would normally
445 be used only if an alternative security model is to be
446 configured. Potentially dangerous and should only be
447 used if you are entirely sure of the consequences.
449 ccw_timeout_log [S390]
450 See Documentation/s390/CommonIO for details.
452 cgroup_disable= [KNL] Disable a particular controller
453 Format: {name of the controller(s) to disable}
454 {Currently supported controllers - "memory"}
456 checkreqprot [SELINUX] Set initial checkreqprot flag value.
457 Format: { "0" | "1" }
458 See security/selinux/Kconfig help text.
459 0 -- check protection applied by kernel (includes
460 any implied execute protection).
461 1 -- check protection requested by application.
462 Default value is set via a kernel config option.
463 Value can be changed at runtime via
464 /selinux/checkreqprot.
467 See Documentation/s390/CommonIO for details.
469 clock= [BUGS=X86-32, HW] gettimeofday clocksource override.
471 Forces specified clocksource (if available) to be used
472 when calculating gettimeofday(). If specified
473 clocksource is not available, it defaults to PIT.
474 Format: { pit | tsc | cyclone | pmtmr }
476 clocksource= Override the default clocksource
478 Override the default clocksource and use the clocksource
479 with the name specified.
480 Some clocksource names to choose from, depending on
482 [all] jiffies (this is the base, fallback clocksource)
484 [ARM] imx_timer1,OSTS,netx_timer,mpu_timer2,
485 pxa_timer,timer3,32k_counter,timer0_1
487 [X86-32] pit,hpet,tsc;
488 scx200_hrt on Geode; cyclone on IBM x440
496 clearcpuid=BITNUM [X86]
497 Disable CPUID feature X for the kernel. See
498 arch/x86/include/asm/cpufeature.h for the valid bit
499 numbers. Note the Linux specific bits are not necessarily
500 stable over kernel options, but the vendor specific
502 Also note that user programs calling CPUID directly
503 or using the feature without checking anything
504 will still see it. This just prevents it from
505 being used by the kernel or shown in /proc/cpuinfo.
506 Also note the kernel might malfunction if you disable
509 cmo_free_hint= [PPC] Format: { yes | no }
510 Specify whether pages are marked as being inactive
511 when they are freed. This is used in CMO environments
512 to determine OS memory pressure for page stealing by
516 code_bytes [X86] How many bytes of object code to print
521 com20020= [HW,NET] ARCnet - COM20020 chipset
523 <io>[,<irq>[,<nodeID>[,<backplane>[,<ckp>[,<timeout>]]]]]
525 com90io= [HW,NET] ARCnet - COM90xx chipset (IO-mapped buffers)
529 ARCnet - COM90xx chipset (memory-mapped buffers)
530 Format: <io>[,<irq>[,<memstart>]]
532 condev= [HW,S390] console device
535 console= [KNL] Output console device and options.
537 tty<n> Use the virtual console device <n>.
541 Use the specified serial port. The options are of
542 the form "bbbbpnf", where "bbbb" is the baud rate,
543 "p" is parity ("n", "o", or "e"), "n" is number of
544 bits, and "f" is flow control ("r" for RTS or
545 omit it). Default is "9600n8".
547 See Documentation/serial-console.txt for more
549 Documentation/networking/netconsole.txt for an
552 uart[8250],io,<addr>[,options]
553 uart[8250],mmio,<addr>[,options]
554 Start an early, polled-mode console on the 8250/16550
555 UART at the specified I/O port or MMIO address,
556 switching to the matching ttyS device later. The
557 options are the same as for ttyS, above.
559 If the device connected to the port is not a TTY but a braille
560 device, prepend "brl," before the device type, for instance
562 For now, only VisioBraille is supported.
564 consoleblank= [KNL] The console blank (screen saver) timeout in
565 seconds. Defaults to 10*60 = 10mins. A value of 0
566 disables the blank timer.
569 [KNL] Change the default value for
570 /proc/<pid>/coredump_filter.
571 See also Documentation/filesystems/proc.txt.
573 cpufreq_driver= [X86] Allow only the named cpu frequency scaling driver
574 to register. Example: cpufreq_driver=powernow-k8
575 Format: { none | STRING }
577 cpuidle.off=1 [CPU_IDLE]
578 disable the cpuidle sub-system
580 cpcihp_generic= [HW,PCI] Generic port I/O CompactPCI driver
582 <first_slot>,<last_slot>,<port>,<enum_bit>[,<debug>]
584 crashkernel=size[KMG][@offset[KMG]]
585 [KNL] Using kexec, Linux can switch to a 'crash kernel'
586 upon panic. This parameter reserves the physical
587 memory region [offset, offset + size] for that kernel
588 image. If '@offset' is omitted, then a suitable offset
589 is selected automatically. Check
590 Documentation/kdump/kdump.txt for further details.
592 crashkernel=range1:size1[,range2:size2,...][@offset]
593 [KNL] Same as above, but depends on the memory
594 in the running system. The syntax of range is
595 start-[end] where start and end are both
596 a memory unit (amount[KMG]). See also
597 Documentation/kdump/kdump.txt for an example.
602 cs89x0_media= [HW,NET]
603 Format: { rj45 | aui | bnc }
606 See header of drivers/s390/block/dasd_devmap.c.
608 db9.dev[2|3]= [HW,JOY] Multisystem joystick support via parallel port
609 (one device per port)
610 Format: <port#>,<type>
611 See also Documentation/input/joystick-parport.txt
613 ddebug_query= [KNL,DYNAMIC_DEBUG] Enable debug messages at early boot
614 time. See Documentation/dynamic-debug-howto.txt for
617 debug [KNL] Enable kernel debugging (events log level).
620 [KNL] verbose self-tests
622 Print debugging info while doing the locking API
624 We default to 0 (no extra messages), setting it to
625 1 will print _a lot_ more information - normally
626 only useful to kernel developers.
628 debug_objects [KNL] Enable object debugging
631 [KNL] Disable object debugging
633 debugpat [X86] Enable PAT debugging
635 decnet.addr= [HW,NET]
636 Format: <area>[,<node>]
637 See also Documentation/networking/decnet.txt.
640 [same as hugepagesz=] The size of the default
641 HugeTLB page size. This is the size represented by
642 the legacy /proc/ hugepages APIs, used for SHM, and
643 default size when mounting hugetlbfs filesystems.
644 Defaults to the default architecture's huge page size
648 Set number of hash buckets for dentry cache.
651 IO parameters + enable/disable command.
653 digiepca= [HW,SERIAL]
654 See drivers/char/README.epca and
655 Documentation/serial/digiepca.txt.
658 See Documentation/networking/ipv6.txt.
660 disable_ddw [PPC/PSERIES]
661 Disable Dynamic DMA Window support. Use this if
662 to workaround buggy firmware.
665 See Documentation/networking/ipv6.txt.
667 disable_mtrr_cleanup [X86]
668 The kernel tries to adjust MTRR layout from continuous
669 to discrete, to make X server driver able to add WB
670 entry later. This parameter disables that.
672 disable_mtrr_trim [X86, Intel and AMD only]
673 By default the kernel will trim any uncacheable
674 memory out of your available memory pool based on
675 MTRR settings. This parameter disables that behavior,
676 possibly causing your machine to run very slowly.
678 disable_timer_pin_1 [X86]
679 Disable PIN 1 of APIC timer
680 Can be useful to work around chipset bugs.
682 dma_debug=off If the kernel is compiled with DMA_API_DEBUG support,
683 this option disables the debugging code at boot.
685 dma_debug_entries=<number>
686 This option allows to tune the number of preallocated
687 entries for DMA-API debugging code. One entry is
688 required per DMA-API allocation. Use this if the
689 DMA-API debugging code disables itself because the
690 architectural default is too low.
692 dma_debug_driver=<driver_name>
693 With this option the DMA-API debugging driver
694 filter feature can be enabled at boot time. Just
695 pass the driver to filter for as the parameter.
696 The filter can be disabled or changed to another
697 driver later using sysfs.
699 drm_kms_helper.edid_firmware=[<connector>:]<file>
700 Broken monitors, graphic adapters and KVMs may
701 send no or incorrect EDID data sets. This parameter
702 allows to specify an EDID data set in the
703 /lib/firmware directory that is used instead.
704 Generic built-in EDID data sets are used, if one of
705 edid/1024x768.bin, edid/1280x1024.bin,
706 edid/1680x1050.bin, or edid/1920x1080.bin is given
707 and no file with the same name exists. Details and
708 instructions how to build your own EDID data are
709 available in Documentation/EDID/HOWTO.txt. An EDID
710 data set will only be used for a particular connector,
711 if its name and a colon are prepended to the EDID
716 earlycon= [KNL] Output early console device and options.
717 uart[8250],io,<addr>[,options]
718 uart[8250],mmio,<addr>[,options]
719 uart[8250],mmio32,<addr>[,options]
720 Start an early, polled-mode console on the 8250/16550
721 UART at the specified I/O port or MMIO address.
722 MMIO inter-register address stride is either 8-bit
723 (mmio) or 32-bit (mmio32).
724 The options are the same as for ttyS, above.
726 earlyprintk= [X86,SH,BLACKFIN]
728 earlyprintk=serial[,ttySn[,baudrate]]
729 earlyprintk=ttySn[,baudrate]
730 earlyprintk=dbgp[debugController#]
732 Append ",keep" to not disable it when the real console
735 Only vga or serial or usb debug port at a time.
737 Currently only ttyS0 and ttyS1 are supported.
739 Interaction with the standard serial driver is not
742 The VGA output is eventually overwritten by the real
745 ekgdboc= [X86,KGDB] Allow early kernel console debugging
748 This is designed to be used in conjunction with
749 the boot argument: earlyprintk=vga
752 Format: {"off" | "on" | "skip[mbr]"}
754 eisa_irq_edge= [PARISC,HW]
755 See header of drivers/parisc/eisa.c.
758 See comment before function elanfreq_setup() in
759 arch/x86/kernel/cpu/cpufreq/elanfreq.c.
762 Format: {"cfq" | "deadline" | "noop"}
763 See Documentation/block/cfq-iosched.txt and
764 Documentation/block/deadline-iosched.txt for details.
766 elfcorehdr=[size[KMG]@]offset[KMG] [IA64,PPC,SH,X86,S390]
767 Specifies physical address of start of kernel core
768 image elf header and optionally the size. Generally
769 kexec loader will pass this option to capture kernel.
770 See Documentation/kdump/kdump.txt for details.
772 enable_mtrr_cleanup [X86]
773 The kernel tries to adjust MTRR layout from continuous
774 to discrete, to make X server driver able to add WB
775 entry later. This parameter enables that.
777 enable_timer_pin_1 [X86]
778 Enable PIN 1 of APIC timer
779 Can be useful to work around chipset bugs
780 (in particular on some ATI chipsets).
781 The kernel tries to set a reasonable default.
783 enforcing [SELINUX] Set initial enforcing status.
785 See security/selinux/Kconfig help text.
786 0 -- permissive (log only, no denials).
787 1 -- enforcing (deny and log).
789 Value can be changed at runtime via /selinux/enforce.
792 Disable Error Record Serialization Table (ERST)
795 ether= [HW,NET] Ethernet cards parameters
796 This option is obsoleted by the "netdev=" option, which
797 has equivalent usage. See its documentation for details.
801 Permit 'security.evm' to be updated regardless of
802 current integrity status.
806 fail_make_request=[KNL]
807 General fault injection mechanism.
808 Format: <interval>,<probability>,<space>,<times>
809 See also Documentation/fault-injection/.
812 See Documentation/blockdev/floppy.txt.
814 force_pal_cache_flush
815 [IA-64] Avoid check_sal_cache_flush which may hang on
816 buggy SAL_CACHE_FLUSH implementations. Using this
817 parameter will force ia64_sal_cache_flush to call
818 ia64_pal_cache_flush instead of SAL_CACHE_FLUSH.
821 [FTRACE] will set and start the specified tracer
822 as early as possible in order to facilitate early
825 ftrace_dump_on_oops[=orig_cpu]
826 [FTRACE] will dump the trace buffers on oops.
827 If no parameter is passed, ftrace will dump
828 buffers of all CPUs, but if you pass orig_cpu, it will
829 dump only the buffer of the CPU that triggered the
832 ftrace_filter=[function-list]
833 [FTRACE] Limit the functions traced by the function
834 tracer at boot up. function-list is a comma separated
835 list of functions. This list can be changed at run
836 time by the set_ftrace_filter file in the debugfs
839 ftrace_notrace=[function-list]
840 [FTRACE] Do not trace the functions specified in
841 function-list. This list can be changed at run time
842 by the set_ftrace_notrace file in the debugfs
845 ftrace_graph_filter=[function-list]
846 [FTRACE] Limit the top level callers functions traced
847 by the function graph tracer at boot up.
848 function-list is a comma separated list of functions
849 that can be changed at run time by the
850 set_graph_function file in the debugfs tracing directory.
853 [HW,JOY] Multisystem joystick and NES/SNES/PSX pad
854 support via parallel port (up to 5 devices per port)
855 Format: <port#>,<pad1>,<pad2>,<pad3>,<pad4>,<pad5>
856 See also Documentation/input/joystick-parport.txt
860 gart_fix_e820= [X86_64] disable the fix e820 for K8 GART
864 gcov_persist= [GCOV] When non-zero (default), profiling data for
865 kernel modules is saved and remains accessible via
866 debugfs, even when the module is unloaded/reloaded.
867 When zero, profiling data is discarded and associated
868 debugfs files are removed at module unload time.
870 gpt [EFI] Forces disk with valid GPT signature but
871 invalid Protective MBR to be treated as GPT.
873 hashdist= [KNL,NUMA] Large hashes allocated during boot
874 are distributed across NUMA nodes. Defaults on
875 for 64-bit NUMA, off otherwise.
876 Format: 0 | 1 (for off | on)
878 hcl= [IA-64] SGI's Hardware Graph compatibility layer
880 hd= [EIDE] (E)IDE hard drive subsystem geometry
881 Format: <cyl>,<head>,<sect>
884 Disable Hardware Error Source Table (HEST) support;
885 corresponding firmware-first mode error processing
886 logic will be disabled.
888 highmem=nn[KMG] [KNL,BOOT] forces the highmem zone to have an exact
889 size of <nn>. This works even on boxes that have no
890 highmem otherwise. This also works to reduce highmem
891 size on bigger boxes.
893 highres= [KNL] Enable/disable high resolution timer mode.
894 Valid parameters: "on", "off"
898 See Documentation/isdn/README.HiSax.
902 hpet= [X86-32,HPET] option to control HPET usage
903 Format: { enable (default) | disable | force |
905 disable: disable HPET and use PIT instead
906 force: allow force enabled of undocumented chips (ICH4,
908 verbose: show contents of HPET registers during setup
910 hugepages= [HW,X86-32,IA-64] HugeTLB pages to allocate at boot.
911 hugepagesz= [HW,IA-64,PPC,X86-64] The size of the HugeTLB pages.
912 On x86-64 and powerpc, this option can be specified
913 multiple times interleaved with hugepages= to reserve
914 huge pages of different sizes. Valid pages sizes on
915 x86-64 are 2M (when the CPU supports "pse") and 1G
916 (when the CPU supports the "pdpe1gb" cpuinfo flag)
917 Note that 1GB pages can only be allocated at boot time
918 using hugepages= and not freed afterwards.
920 hvc_iucv= [S390] Number of z/VM IUCV hypervisor console (HVC)
921 terminal devices. Valid values: 0..8
922 hvc_iucv_allow= [S390] Comma-separated list of z/VM user IDs.
923 If specified, z/VM IUCV HVC accepts connections
924 from listed z/VM user IDs only.
927 Do not unregister boot console at start. This is only
928 useful for debugging when something happens in the window
929 between unregistering the boot console and initializing
932 i2c_bus= [HW] Override the default board specific I2C bus speed
933 or register an additional I2C bus that is not
934 registered from board initialization code.
938 i8042.debug [HW] Toggle i8042 debug mode
939 i8042.direct [HW] Put keyboard port into non-translated mode
940 i8042.dumbkbd [HW] Pretend that controller can only read data from
941 keyboard and cannot control its state
942 (Don't attempt to blink the leds)
943 i8042.noaux [HW] Don't check for auxiliary (== mouse) port
944 i8042.nokbd [HW] Don't check/create keyboard port
945 i8042.noloop [HW] Disable the AUX Loopback command while probing
947 i8042.nomux [HW] Don't check presence of an active multiplexing
949 i8042.nopnp [HW] Don't use ACPIPnP / PnPBIOS to discover KBD/AUX
951 i8042.notimeout [HW] Ignore timeout condition signalled by conroller
952 i8042.reset [HW] Reset the controller during init and cleanup
953 i8042.unlock [HW] Unlock (ignore) the keylock
957 i8k.ignore_dmi [HW] Continue probing hardware even if DMI data
958 indicates that the driver is running on unsupported
960 i8k.force [HW] Activate i8k driver even if SMM BIOS signature
961 does not match list of supported models.
963 [HW] Report power status in /proc/i8k
964 (disabled by default)
965 i8k.restricted [HW] Allow controlling fans only if SYS_ADMIN
969 Format: <io>[,<membase>[,<icn_id>[,<icn_id2>]]]
971 ide-core.nodma= [HW] (E)IDE subsystem
972 Format: =0.0 to prevent dma on hda, =0.1 hdb =1.0 hdc
973 .vlb_clock .pci_clock .noflush .nohpa .noprobe .nowerr
974 .cdrom .chs .ignore_cable are additional options
975 See Documentation/ide/ide.txt.
977 ide-pci-generic.all-generic-ide [HW] (E)IDE subsystem
978 Claim all unknown PCI IDE storage controllers.
981 Format: idle=poll, idle=mwait, idle=halt, idle=nomwait
982 Poll forces a polling idle loop that can slightly
983 improve the performance of waking up a idle CPU, but
984 will use a lot of power and make the system run hot.
986 idle=mwait: On systems which support MONITOR/MWAIT but
987 the kernel chose to not use it because it doesn't save
988 as much power as a normal idle loop, use the
989 MONITOR/MWAIT idle loop anyways. Performance should be
990 the same as idle=poll.
991 idle=halt: Halt is forced to be used for CPU idle.
992 In such case C2/C3 won't be used again.
993 idle=nomwait: Disable mwait for CPU C-states
995 ignore_loglevel [KNL]
996 Ignore loglevel setting - this will print /all/
997 kernel messages to the console. Useful for debugging.
998 We also add it as printk module parameter, so users
999 could change it dynamically, usually by
1000 /sys/module/printk/parameters/ignore_loglevel.
1002 ihash_entries= [KNL]
1003 Set number of hash buckets for inode cache.
1006 Format: { "0" | "1" }
1007 0 -- integrity auditing messages. (Default)
1008 1 -- enable informational integrity auditing messages.
1011 Format: { "sha1" | "md5" }
1015 Load a policy which meets the needs of the Trusted
1016 Computing Base. This means IMA will measure all
1017 programs exec'd, files mmap'd for exec, and all files
1018 opened for read by uid=0.
1022 Run specified binary instead of /sbin/init as init
1025 initcall_debug [KNL] Trace initcalls as they are executed. Useful
1026 for working out where the kernel is dying during
1029 initrd= [BOOT] Specify the location of the initial ramdisk
1031 inport.irq= [HW] Inport (ATI XL and Microsoft) busmouse driver
1034 intel_iommu= [DMAR] Intel IOMMU driver (DMAR) option
1036 Enable intel iommu driver.
1038 Disable intel iommu driver.
1039 igfx_off [Default Off]
1040 By default, gfx is mapped as normal device. If a gfx
1041 device has a dedicated DMAR unit, the DMAR unit is
1042 bypassed by not enabling DMAR with this option. In
1043 this case, gfx device will use physical address for
1046 With this option iommu will not optimize to look
1047 for io virtual address below 32-bit forcing dual
1048 address cycle on pci bus for cards supporting greater
1049 than 32-bit addressing. The default is to look
1050 for translation below 32-bit and if not available
1051 then look in the higher range.
1052 strict [Default Off]
1053 With this option on every unmap_single operation will
1054 result in a hardware IOTLB flush operation as opposed
1055 to batching them for performance.
1056 sp_off [Default Off]
1057 By default, super page will be supported if Intel IOMMU
1058 has the capability. With this option, super page will
1060 intremap= [X86-64, Intel-IOMMU]
1061 on enable Interrupt Remapping (default)
1062 off disable Interrupt Remapping
1063 nosid disable Source ID checking
1065 BIOS x2APIC opt-out request will be ignored
1069 iomem= Disable strict checking of access to MMIO memory
1070 strict regions from userspace.
1086 io7= [HW] IO7 for Marvel based alpha systems
1087 See comment before marvel_specify_io7 in
1088 arch/alpha/kernel/core_marvel.c.
1090 io_delay= [X86] I/O delay method
1092 Standard port 0x80 based delay
1094 Alternate port 0xed based delay (needed on some systems)
1096 Simple two microseconds delay
1101 See Documentation/filesystems/nfs/nfsroot.txt.
1103 ip2= [HW] Set IO/IRQ pairs for up to 4 IntelliPort boards
1104 See comment before ip2_setup() in
1105 drivers/char/ip2/ip2base.c.
1108 When an interrupt is not handled search all handlers
1109 for it. Intended to get systems with badly broken
1113 When an interrupt is not handled search all handlers
1114 for it. Also check all handlers each timer
1115 interrupt. Intended to get systems with badly broken
1119 Format: <RDP>,<reset>,<pci_scan>,<verbosity>
1121 isolcpus= [KNL,SMP] Isolate CPUs from the general scheduler.
1123 <cpu number>,...,<cpu number>
1125 <cpu number>-<cpu number>
1126 (must be a positive range in ascending order)
1128 <cpu number>,...,<cpu number>-<cpu number>
1130 This option can be used to specify one or more CPUs
1131 to isolate from the general SMP balancing and scheduling
1132 algorithms. You can move a process onto or off an
1133 "isolated" CPU via the CPU affinity syscalls or cpuset.
1134 <cpu number> begins at 0 and the maximum value is
1135 "number of CPUs in system - 1".
1137 This option is the preferred way to isolate CPUs. The
1138 alternative -- manually setting the CPU mask of all
1139 tasks in the system -- can cause problems and
1140 suboptimal load balancer performance.
1144 js= [HW,JOY] Analog joystick
1145 See Documentation/input/joystick.txt.
1149 kernelcore=nn[KMG] [KNL,X86,IA-64,PPC] This parameter
1150 specifies the amount of memory usable by the kernel
1151 for non-movable allocations. The requested amount is
1152 spread evenly throughout all nodes in the system. The
1153 remaining memory in each node is used for Movable
1154 pages. In the event, a node is too small to have both
1155 kernelcore and Movable pages, kernelcore pages will
1156 take priority and other nodes will have a larger number
1157 of kernelcore pages. The Movable zone is used for the
1158 allocation of pages that may be reclaimed or moved
1159 by the page migration subsystem. This means that
1160 HugeTLB pages may not be allocated from this zone.
1161 Note that allocations like PTEs-from-HighMem still
1162 use the HighMem zone if it exists, and the Normal
1163 zone if it does not.
1165 kgdbdbgp= [KGDB,HW] kgdb over EHCI usb debug port.
1166 Format: <Controller#>[,poll interval]
1167 The controller # is the number of the ehci usb debug
1168 port as it is probed via PCI. The poll interval is
1169 optional and is the number seconds in between
1170 each poll cycle to the debug port in case you need
1171 the functionality for interrupting the kernel with
1172 gdb or control-c on the dbgp connection. When
1173 not using this parameter you use sysrq-g to break into
1174 the kernel debugger.
1176 kgdboc= [KGDB,HW] kgdb over consoles.
1177 Requires a tty driver that supports console polling,
1178 or a supported polling keyboard driver (non-usb).
1179 Serial only format: <serial_device>[,baud]
1180 keyboard only format: kbd
1181 keyboard and serial format: kbd,<serial_device>[,baud]
1182 Optional Kernel mode setting:
1183 kms, kbd format: kms,kbd
1184 kms, kbd and serial format: kms,kbd,<ser_dev>[,baud]
1186 kgdbwait [KGDB] Stop kernel execution and enter the
1187 kernel debugger at the earliest opportunity.
1189 kmac= [MIPS] korina ethernet MAC address.
1190 Configure the RouterBoard 532 series on-chip
1191 Ethernet adapter MAC address.
1193 kmemleak= [KNL] Boot-time kmemleak enable/disable
1194 Valid arguments: on, off
1197 kstack=N [X86] Print N words from the kernel stack
1200 kvm.ignore_msrs=[KVM] Ignore guest accesses to unhandled MSRs.
1201 Default is 0 (don't ignore, but inject #GP)
1203 kvm.oos_shadow= [KVM] Disable out-of-sync shadow paging.
1204 Default is 1 (enabled)
1206 kvm.mmu_audit= [KVM] This is a R/W parameter which allows audit
1210 kvm-amd.nested= [KVM,AMD] Allow nested virtualization in KVM/SVM.
1211 Default is 1 (enabled)
1213 kvm-amd.npt= [KVM,AMD] Disable nested paging (virtualized MMU)
1215 Default is 1 (enabled) if in 64-bit or 32-bit PAE mode.
1217 kvm-intel.ept= [KVM,Intel] Disable extended page tables
1218 (virtualized MMU) support on capable Intel chips.
1219 Default is 1 (enabled)
1221 kvm-intel.emulate_invalid_guest_state=
1222 [KVM,Intel] Enable emulation of invalid guest states
1223 Default is 0 (disabled)
1225 kvm-intel.flexpriority=
1226 [KVM,Intel] Disable FlexPriority feature (TPR shadow).
1227 Default is 1 (enabled)
1230 [KVM,Intel] Enable VMX nesting (nVMX).
1231 Default is 0 (disabled)
1233 kvm-intel.unrestricted_guest=
1234 [KVM,Intel] Disable unrestricted guest feature
1235 (virtualized real and unpaged mode) on capable
1236 Intel chips. Default is 1 (enabled)
1238 kvm-intel.vpid= [KVM,Intel] Disable Virtual Processor Identification
1239 feature (tagged TLBs) on capable Intel chips.
1240 Default is 1 (enabled)
1246 lapic [X86-32,APIC] Enable the local APIC even if BIOS
1249 lapic_timer_c2_ok [X86,APIC] trust the local apic timer
1252 libata.dma= [LIBATA] DMA control
1253 libata.dma=0 Disable all PATA and SATA DMA
1254 libata.dma=1 PATA and SATA Disk DMA only
1255 libata.dma=2 ATAPI (CDROM) DMA only
1256 libata.dma=4 Compact Flash DMA only
1257 Combinations also work, so libata.dma=3 enables DMA
1258 for disks and CDROMs, but not CFs.
1260 libata.ignore_hpa= [LIBATA] Ignore HPA limit
1261 libata.ignore_hpa=0 keep BIOS limits (default)
1262 libata.ignore_hpa=1 ignore limits, using full disk
1264 libata.noacpi [LIBATA] Disables use of ACPI in libata suspend/resume
1268 libata.force= [LIBATA] Force configurations. The format is comma
1269 separated list of "[ID:]VAL" where ID is
1270 PORT[.DEVICE]. PORT and DEVICE are decimal numbers
1271 matching port, link or device. Basically, it matches
1272 the ATA ID string printed on console by libata. If
1273 the whole ID part is omitted, the last PORT and DEVICE
1274 values are used. If ID hasn't been specified yet, the
1275 configuration applies to all ports, links and devices.
1277 If only DEVICE is omitted, the parameter applies to
1278 the port and all links and devices behind it. DEVICE
1279 number of 0 either selects the first device or the
1280 first fan-out link behind PMP device. It does not
1281 select the host link. DEVICE number of 15 selects the
1282 host link and device attached to it.
1284 The VAL specifies the configuration to force. As long
1285 as there's no ambiguity shortcut notation is allowed.
1286 For example, both 1.5 and 1.5G would work for 1.5Gbps.
1287 The following configurations can be forced.
1289 * Cable type: 40c, 80c, short40c, unk, ign or sata.
1290 Any ID with matching PORT is used.
1292 * SATA link speed limit: 1.5Gbps or 3.0Gbps.
1294 * Transfer mode: pio[0-7], mwdma[0-4] and udma[0-7].
1295 udma[/][16,25,33,44,66,100,133] notation is also
1298 * [no]ncq: Turn on or off NCQ.
1300 * nohrst, nosrst, norst: suppress hard, soft
1303 * dump_id: dump IDENTIFY data.
1305 If there are multiple matching configurations changing
1306 the same attribute, the last one is used.
1308 memblock=debug [KNL] Enable memblock debug messages.
1310 load_ramdisk= [RAM] List of ramdisks to load from floppy
1311 See Documentation/blockdev/ramdisk.txt.
1313 lockd.nlm_grace_period=P [NFS] Assign grace period.
1316 lockd.nlm_tcpport=N [NFS] Assign TCP port.
1319 lockd.nlm_timeout=T [NFS] Assign timeout value.
1322 lockd.nlm_udpport=M [NFS] Assign UDP port.
1325 logibm.irq= [HW,MOUSE] Logitech Bus Mouse Driver
1328 loglevel= All Kernel Messages with a loglevel smaller than the
1329 console loglevel will be printed to the console. It can
1330 also be changed with klogd or other programs. The
1331 loglevels are defined as follows:
1333 0 (KERN_EMERG) system is unusable
1334 1 (KERN_ALERT) action must be taken immediately
1335 2 (KERN_CRIT) critical conditions
1336 3 (KERN_ERR) error conditions
1337 4 (KERN_WARNING) warning conditions
1338 5 (KERN_NOTICE) normal but significant condition
1339 6 (KERN_INFO) informational
1340 7 (KERN_DEBUG) debug-level messages
1342 log_buf_len=n[KMG] Sets the size of the printk ring buffer,
1343 in bytes. n must be a power of two. The default
1344 size is set in the kernel config file.
1346 logo.nologo [FB] Disables display of the built-in Linux logo.
1347 This may be used to provide more screen space for
1348 kernel log messages and is useful when debugging
1349 kernel boot problems.
1351 lp=0 [LP] Specify parallel ports to use, e.g,
1352 lp=port[,port...] lp=none,parport0 (lp0 not configured, lp1 uses
1353 lp=reset first parallel port). 'lp=0' disables the
1354 lp=auto printer driver. 'lp=reset' (which can be
1355 specified in addition to the ports) causes
1356 attached printers to be reset. Using
1357 lp=port1,port2,... specifies the parallel ports
1358 to associate lp devices with, starting with
1359 lp0. A port specification may be 'none' to skip
1360 that lp device, or a parport name such as
1361 'parport0'. Specifying 'lp=auto' instead of a
1362 port specification list means that device IDs
1363 from each port should be examined, to see if
1364 an IEEE 1284-compliant printer is attached; if
1365 so, the driver will manage that printer.
1366 See also header of drivers/char/lp.c.
1369 Sets loops_per_jiffy to given constant, thus avoiding
1370 time-consuming boot-time autodetection (up to 250 ms per
1371 CPU). 0 enables autodetection (default). To determine
1372 the correct value for your kernel, boot with normal
1373 autodetection and see what value is printed. Note that
1374 on SMP systems the preset will be applied to all CPUs,
1375 which is likely to cause problems if your CPUs need
1376 significantly divergent settings. An incorrect value
1377 will cause delays in the kernel to be wrong, leading to
1378 unpredictable I/O errors and other breakage. Although
1379 unlikely, in the extreme case this might damage your
1383 Format: <io>,<irq>,<dma>
1385 machvec= [IA-64] Force the use of a particular machine-vector
1386 (machvec) in a generic kernel.
1387 Example: machvec=hpzx1_swiotlb
1389 machtype= [Loongson] Share the same kernel image file between different
1391 Example: machtype=lemote-yeeloong-2f-7inch
1393 max_addr=nn[KMG] [KNL,BOOT,ia64] All physical memory greater
1394 than or equal to this physical address is ignored.
1396 maxcpus= [SMP] Maximum number of processors that an SMP kernel
1397 should make use of. maxcpus=n : n >= 0 limits the
1398 kernel to using 'n' processors. n=0 is a special case,
1399 it is equivalent to "nosmp", which also disables
1402 max_loop= [LOOP] The number of loop block devices that get
1403 (loop.max_loop) unconditionally pre-created at init time. The default
1404 number is configured by BLK_DEV_LOOP_MIN_COUNT. Instead
1405 of statically allocating a predefined number, loop
1406 devices can be requested on-demand with the
1407 /dev/loop-control interface.
1411 mce [X86-32] Machine Check Exception
1413 mce=option [X86-64] See Documentation/x86/x86_64/boot-options.txt
1415 md= [HW] RAID subsystems devices and level
1416 See Documentation/md.txt.
1419 Format: <first>,<last>
1420 Specifies range of consoles to be captured by the MDA.
1422 mem=nn[KMG] [KNL,BOOT] Force usage of a specific amount of memory
1423 Amount of memory to be used when the kernel is not able
1424 to see the whole system memory or for test.
1425 [X86-32] Use together with memmap= to avoid physical
1426 address space collisions. Without memmap= PCI devices
1427 could be placed at addresses belonging to unused RAM.
1429 mem=nopentium [BUGS=X86-32] Disable usage of 4MB pages for kernel
1433 [KNL,SH] Allow user to override the default size for
1434 per-device physically contiguous DMA buffers.
1436 memmap=exactmap [KNL,X86] Enable setting of an exact
1437 E820 memory map, as specified by the user.
1438 Such memmap=exactmap lines can be constructed based on
1439 BIOS output or other requirements. See the memmap=nn@ss
1442 memmap=nn[KMG]@ss[KMG]
1443 [KNL] Force usage of a specific region of memory
1444 Region of memory to be used, from ss to ss+nn.
1446 memmap=nn[KMG]#ss[KMG]
1447 [KNL,ACPI] Mark specific memory as ACPI data.
1448 Region of memory to be used, from ss to ss+nn.
1450 memmap=nn[KMG]$ss[KMG]
1451 [KNL,ACPI] Mark specific memory as reserved.
1452 Region of memory to be used, from ss to ss+nn.
1453 Example: Exclude memory from 0x18690000-0x1869ffff
1454 memmap=64K$0x18690000
1456 memmap=0x10000$0x18690000
1458 memory_corruption_check=0/1 [X86]
1459 Some BIOSes seem to corrupt the first 64k of
1460 memory when doing things like suspend/resume.
1461 Setting this option will scan the memory
1462 looking for corruption. Enabling this will
1463 both detect corruption and prevent the kernel
1464 from using the memory being corrupted.
1465 However, its intended as a diagnostic tool; if
1466 repeatable BIOS-originated corruption always
1467 affects the same memory, you can use memmap=
1468 to prevent the kernel from using that memory.
1470 memory_corruption_check_size=size [X86]
1471 By default it checks for corruption in the low
1472 64k, making this memory unavailable for normal
1473 use. Use this parameter to scan for
1474 corruption in more or less memory.
1476 memory_corruption_check_period=seconds [X86]
1477 By default it checks for corruption every 60
1478 seconds. Use this parameter to check at some
1479 other rate. 0 disables periodic checking.
1481 memtest= [KNL,X86] Enable memtest
1483 default : 0 <disable>
1484 Specifies the number of memtest passes to be
1485 performed. Each pass selects another test
1486 pattern from a given set of patterns. Memtest
1487 fills the memory with this pattern, validates
1488 memory contents and reserves bad memory
1489 regions that are detected.
1491 meye.*= [HW] Set MotionEye Camera parameters
1492 See Documentation/video4linux/meye.txt.
1494 mfgpt_irq= [IA-32] Specify the IRQ to use for the
1495 Multi-Function General Purpose Timers on AMD Geode
1498 mfgptfix [X86-32] Fix MFGPT timers on AMD Geode platforms when
1499 the BIOS has incorrectly applied a workaround. TinyBIOS
1500 version 0.98 is known to be affected, 0.99 fixes the
1501 problem by letting the user disable the workaround.
1505 min_addr=nn[KMG] [KNL,BOOT,ia64] All physical memory below this
1506 physical address is ignored.
1508 mini2440= [ARM,HW,KNL]
1509 Format:[0..2][b][c][t]
1511 MINI2440 configuration specification:
1512 0 - The attached screen is the 3.5" TFT
1513 1 - The attached screen is the 7" TFT
1514 2 - The VGA Shield is attached (1024x768)
1515 Leaving out the screen size parameter will not load
1516 the TFT driver, and the framebuffer will be left
1518 b - Enable backlight. The TFT backlight pin will be
1519 linked to the kernel VESA blanking code and a GPIO
1520 LED. This parameter is not necessary when using the
1522 c - Enable the s3c camera interface.
1523 t - Reserved for enabling touchscreen support. The
1524 touchscreen support is not enabled in the mainstream
1525 kernel as of 2.6.30, a preliminary port can be found
1526 in the "bleeding edge" mini2440 support kernel at
1527 http://repo.or.cz/w/linux-2.6/mini2440.git
1530 [KNL] When CONFIG_DEBUG_MEMORY_INIT is set, this
1531 parameter allows control of the logging verbosity for
1532 the additional memory initialisation checks. A value
1533 of 0 disables mminit logging and a level of 4 will
1534 log everything. Information is printed at KERN_DEBUG
1535 so loglevel=8 may also need to be specified.
1538 [MOUSE] Maximum time between finger touching and
1539 leaving touchpad surface for touch to be considered
1540 a tap and be reported as a left button click (for
1541 touchpads working in absolute mode only).
1543 mousedev.xres= [MOUSE] Horizontal screen resolution, used for devices
1544 reporting absolute coordinates, such as tablets
1545 mousedev.yres= [MOUSE] Vertical screen resolution, used for devices
1546 reporting absolute coordinates, such as tablets
1548 movablecore=nn[KMG] [KNL,X86,IA-64,PPC] This parameter
1549 is similar to kernelcore except it specifies the
1550 amount of memory used for migratable allocations.
1551 If both kernelcore and movablecore is specified,
1552 then kernelcore will be at *least* the specified
1553 value but may be more. If movablecore on its own
1554 is specified, the administrator must be careful
1555 that the amount of memory usable for all allocations
1558 MTD_Partition= [MTD]
1559 Format: <name>,<region-number>,<size>,<offset>
1561 MTD_Region= [MTD] Format:
1562 <name>,<region-number>[,<base>,<size>,<buswidth>,<altbuswidth>]
1565 See drivers/mtd/cmdlinepart.c.
1567 multitce=off [PPC] This parameter disables the use of the pSeries
1568 firmware feature for updating multiple TCE entries
1571 onenand.bdry= [HW,MTD] Flex-OneNAND Boundary Configuration
1573 Format: [die0_boundary][,die0_lock][,die1_boundary][,die1_lock]
1575 boundary - index of last SLC block on Flex-OneNAND.
1576 The remaining blocks are configured as MLC blocks.
1577 lock - Configure if Flex-OneNAND boundary should be locked.
1578 Once locked, the boundary cannot be changed.
1579 1 indicates lock status, 0 indicates unlock status.
1582 ARM/S3C2412 JIVE boot control
1584 See arch/arm/mach-s3c2412/mach-jive.c
1586 mtouchusb.raw_coordinates=
1587 [HW] Make the MicroTouch USB driver use raw coordinates
1588 ('y', default) or cooked coordinates ('n')
1590 mtrr_chunk_size=nn[KMG] [X86]
1591 used for mtrr cleanup. It is largest continuous chunk
1592 that could hold holes aka. UC entries.
1594 mtrr_gran_size=nn[KMG] [X86]
1595 Used for mtrr cleanup. It is granularity of mtrr block.
1597 Large value could prevent small alignment from
1600 mtrr_spare_reg_nr=n [X86]
1602 Range: 0,7 : spare reg number
1604 Used for mtrr cleanup. It is spare mtrr entries number.
1605 Set to 2 or more if your graphical card needs more.
1607 n2= [NET] SDL Inc. RISCom/N2 synchronous serial card
1609 netdev= [NET] Network devices parameters
1610 Format: <irq>,<io>,<mem_start>,<mem_end>,<name>
1611 Note that mem_start is often overloaded to mean
1612 something different and driver-specific.
1613 This usage is only documented in each driver source
1617 [NETFILTER] Enable connection tracking flow accounting
1618 0 to disable accounting
1619 1 to enable accounting
1622 nfsaddrs= [NFS] Deprecated. Use ip= instead.
1623 See Documentation/filesystems/nfs/nfsroot.txt.
1625 nfsroot= [NFS] nfs root filesystem for disk-less boxes.
1626 See Documentation/filesystems/nfs/nfsroot.txt.
1628 nfsrootdebug [NFS] enable nfsroot debugging messages.
1629 See Documentation/filesystems/nfs/nfsroot.txt.
1631 nfs.callback_tcpport=
1632 [NFS] set the TCP port on which the NFSv4 callback
1633 channel should listen.
1636 [NFS] sets the pathname to the program which is used
1637 to update the NFS client cache entries.
1639 nfs.cache_getent_timeout=
1640 [NFS] sets the timeout after which an attempt to
1641 update a cache entry is deemed to have failed.
1643 nfs.idmap_cache_timeout=
1644 [NFS] set the maximum lifetime for idmapper cache
1648 [NFS] enable 64-bit inode numbers.
1649 If zero, the NFS client will fake up a 32-bit inode
1650 number for the readdir() and stat() syscalls instead
1651 of returning the full 64-bit number.
1652 The default is to return 64-bit inode numbers.
1654 nfs.nfs4_disable_idmapping=
1655 [NFSv4] When set, this option disables the NFSv4
1656 idmapper on the client, but only if the mount
1657 is using the 'sec=sys' security flavour. This may
1658 make migration from legacy NFSv2/v3 systems easier
1659 provided that the server has the appropriate support.
1660 The default is to always enable NFSv4 idmapping.
1662 nmi_debug= [KNL,AVR32,SH] Specify one or more actions to take
1663 when a NMI is triggered.
1664 Format: [state][,regs][,debounce][,die]
1666 nmi_watchdog= [KNL,BUGS=X86] Debugging features for SMP kernels
1667 Format: [panic,][nopanic,][num]
1669 0 - turn nmi_watchdog off
1670 When panic is specified, panic when an NMI watchdog
1671 timeout occurs (or 'nopanic' to override the opposite
1673 This is useful when you use a panic=... timeout and
1674 need the box quickly up again.
1676 netpoll.carrier_timeout=
1677 [NET] Specifies amount of time (in seconds) that
1678 netpoll should wait for a carrier. By default netpoll
1681 no387 [BUGS=X86-32] Tells the kernel to use the 387 maths
1682 emulation library even if a 387 maths coprocessor
1686 [HW] Never suspend the console
1687 Disable suspending of consoles during suspend and
1688 hibernate operations. Once disabled, debugging
1689 messages can reach various consoles while the rest
1690 of the system is being put to sleep (ie, while
1691 debugging driver suspend/resume hooks). This may
1692 not work reliably with all consoles, but is known
1693 to work with serial and VGA consoles.
1694 To facilitate more flexible debugging, we also add
1695 console_suspend, a printk module parameter to control
1696 it. Users could use console_suspend (usually
1697 /sys/module/printk/parameters/console_suspend) to
1698 turn on/off it dynamically.
1700 noaliencache [MM, NUMA, SLAB] Disables the allocation of alien
1701 caches in the slab allocator. Saves per-node memory,
1702 but will impact performance.
1706 noapic [SMP,APIC] Tells the kernel to not make use of any
1707 IOAPICs that may be present in the system.
1709 noautogroup Disable scheduler automatic task group creation.
1711 nobats [PPC] Do not use BATs for mapping kernel lowmem
1712 on "Classic" PPC cores.
1716 noclflush [BUGS=X86] Don't use the CLFLUSH instruction
1718 nodelayacct [KNL] Disable per-task delay accounting
1720 nodisconnect [HW,SCSI,M68K] Disables SCSI disconnects.
1722 nodsp [SH] Disable hardware DSP at boot time.
1724 noefi [X86] Disable EFI runtime services support.
1729 On X86-32 available only on PAE configured kernels.
1730 noexec=on: enable non-executable mappings (default)
1731 noexec=off: disable non-executable mappings
1734 Disable SMEP (Supervisor Mode Execution Protection)
1735 even if it is supported by processor.
1738 This affects only 32-bit executables.
1739 noexec32=on: enable non-executable mappings (default)
1740 read doesn't imply executable mappings
1741 noexec32=off: disable non-executable mappings
1742 read implies executable mappings
1744 nofpu [SH] Disable hardware FPU at boot time.
1746 nofxsr [BUGS=X86-32] Disables x86 floating point extended
1747 register save and restore. The kernel will only save
1748 legacy floating-point registers on task switch.
1750 noxsave [BUGS=X86] Disables x86 extended register state save
1751 and restore using xsave. The kernel will fallback to
1752 enabling legacy floating-point and sse state.
1754 nohlt [BUGS=ARM,SH] Tells the kernel that the sleep(SH) or
1755 wfi(ARM) instruction doesn't work correctly and not to
1756 use it. This is also useful when using JTAG debugger.
1758 no-hlt [BUGS=X86-32] Tells the kernel that the hlt
1759 instruction doesn't work correctly and not to
1762 no_file_caps Tells the kernel not to honor file capabilities. The
1763 only way then for a file to be executed with privilege
1764 is to be setuid root or executed by root.
1766 nohalt [IA-64] Tells the kernel not to use the power saving
1767 function PAL_HALT_LIGHT when idle. This increases
1768 power-consumption. On the positive side, it reduces
1769 interrupt wake-up latency, which may improve performance
1770 in certain environments such as networked servers or
1773 nohz= [KNL] Boottime enable/disable dynamic ticks
1774 Valid arguments: on, off
1777 noiotrap [SH] Disables trapped I/O port accesses.
1779 noirqdebug [X86-32] Disables the code which attempts to detect and
1780 disable unhandled interrupt sources.
1782 no_timer_check [X86,APIC] Disables the code which tests for
1783 broken timer IRQ sources.
1785 noisapnp [ISAPNP] Disables ISA PnP code.
1787 noinitrd [RAM] Tells the kernel not to load any configured
1790 nointremap [X86-64, Intel-IOMMU] Do not enable interrupt
1792 [Deprecated - use intremap=off]
1796 nojitter [IA-64] Disables jitter checking for ITC timers.
1798 no-kvmclock [X86,KVM] Disable paravirtualized KVM clock driver
1800 no-kvmapf [X86,KVM] Disable paravirtualized asynchronous page
1803 no-steal-acc [X86,KVM] Disable paravirtualized steal time accounting.
1804 steal time is computed, but won't influence scheduler
1807 nolapic [X86-32,APIC] Do not enable or use the local APIC.
1809 nolapic_timer [X86-32,APIC] Do not use the local APIC timer.
1811 noltlbs [PPC] Do not use large page/tlb entries for kernel
1812 lowmem mapping on PPC40x.
1814 nomca [IA-64] Disable machine check abort handling
1816 nomce [X86-32] Machine Check Exception
1818 nomfgpt [X86-32] Disable Multi-Function General Purpose
1819 Timer usage (for AMD Geode machines).
1821 nopat [X86] Disable PAT (page attribute table extension of
1822 pagetables) support.
1824 norandmaps Don't use address space randomization. Equivalent to
1825 echo 0 > /proc/sys/kernel/randomize_va_space
1827 noreplace-paravirt [X86,IA-64,PV_OPS] Don't patch paravirt_ops
1829 noreplace-smp [X86-32,SMP] Don't replace SMP instructions
1830 with UP alternatives
1832 noresidual [PPC] Don't use residual data on PReP machines.
1834 nordrand [X86] Disable the direct use of the RDRAND
1835 instruction even if it is supported by the
1836 processor. RDRAND is still available to user
1839 noresume [SWSUSP] Disables resume and restores original swap
1842 no-scroll [VGA] Disables scrollback.
1843 This is required for the Braillex ib80-piezo Braille
1844 reader made by F.H. Papenmeier (Germany).
1848 nosep [BUGS=X86-32] Disables x86 SYSENTER/SYSEXIT support.
1850 nosmp [SMP] Tells an SMP kernel to act as a UP kernel,
1851 and disable the IO APIC. legacy for "maxcpus=0".
1853 nosoftlockup [KNL] Disable the soft-lockup detector.
1855 nosync [HW,M68K] Disables sync negotiation for all devices.
1857 notsc [BUGS=X86-32] Disable Time Stamp Counter
1859 nousb [USB] Disable the USB subsystem
1861 nowatchdog [KNL] Disable the lockup detector (NMI watchdog).
1865 nox2apic [X86-64,APIC] Do not enable x2APIC mode.
1867 nptcg= [IA-64] Override max number of concurrent global TLB
1868 purges which is reported from either PAL_VM_SUMMARY or
1871 nr_cpus= [SMP] Maximum number of processors that an SMP kernel
1872 could support. nr_cpus=n : n >= 1 limits the kernel to
1873 supporting 'n' processors. Later in runtime you can not
1874 use hotplug cpu feature to put more cpu back to online.
1875 just like you compile the kernel NR_CPUS=n
1877 nr_uarts= [SERIAL] maximum number of UARTs to be registered.
1879 numa_zonelist_order= [KNL, BOOT] Select zonelist order for NUMA.
1880 one of ['zone', 'node', 'default'] can be specified
1881 This can be set from sysctl after boot.
1882 See Documentation/sysctl/vm.txt for details.
1884 ohci1394_dma=early [HW] enable debugging via the ohci1394 driver.
1885 See Documentation/debugging-via-ohci1394.txt for more
1888 olpc_ec_timeout= [OLPC] ms delay when issuing EC commands
1889 Rather than timing out after 20 ms if an EC
1890 command is not properly ACKed, override the length
1891 of the timeout. We have interrupts disabled while
1892 waiting for the ACK, so if this is set too high
1893 interrupts *may* be lost!
1895 omap_mux= [OMAP] Override bootloader pin multiplexing.
1896 Format: <mux_mode0.mode_name=value>...
1897 For example, to override I2C bus2:
1898 omap_mux=i2c2_scl.i2c2_scl=0x100,i2c2_sda.i2c2_sda=0x100
1900 oprofile.timer= [HW]
1901 Use timer interrupt instead of performance counters
1903 oprofile.cpu_type= Force an oprofile cpu type
1904 This might be useful if you have an older oprofile
1905 userland or if you want common events.
1906 Format: { arch_perfmon }
1907 arch_perfmon: [X86] Force use of architectural
1908 perfmon on Intel CPUs instead of the
1909 CPU specific event set.
1911 oops=panic Always panic on oopses. Default is to just kill the
1912 process, but there is a small probability of
1913 deadlocking the machine.
1914 This will also cause panics on machine check exceptions.
1915 Useful together with panic=30 to trigger a reboot.
1918 See Documentation/sound/oss/oss-parameters.txt
1920 panic= [KNL] Kernel behaviour on panic: delay <timeout>
1921 timeout > 0: seconds before rebooting
1922 timeout = 0: wait forever
1923 timeout < 0: reboot immediately
1926 parkbd.port= [HW] Parallel port number the keyboard adapter is
1927 connected to, default is 0.
1929 parkbd.mode= [HW] Parallel port keyboard adapter mode of operation,
1930 0 for XT, 1 for AT (default is AT).
1933 parport= [HW,PPT] Specify parallel ports. 0 disables.
1934 Format: { 0 | auto | 0xBBB[,IRQ[,DMA]] }
1935 Use 'auto' to force the driver to use any
1936 IRQ/DMA settings detected (the default is to
1937 ignore detected IRQ/DMA settings because of
1938 possible conflicts). You can specify the base
1939 address, IRQ, and DMA settings; IRQ and DMA
1940 should be numbers, or 'auto' (for using detected
1941 settings on that particular port), or 'nofifo'
1942 (to avoid using a FIFO even if it is detected).
1943 Parallel ports are assigned in the order they
1944 are specified on the command line, starting
1947 parport_init_mode= [HW,PPT]
1948 Configure VIA parallel port to operate in
1949 a specific mode. This is necessary on Pegasos
1950 computer where firmware has no options for setting
1951 up parallel port mode and sets it to spp.
1952 Currently this function knows 686a and 8231 chips.
1953 Format: [spp|ps2|epp|ecp|ecpepp]
1956 Halt all CPUs after the first oops has been printed for
1957 the specified number of seconds. This is to be used if
1958 your oopses keep scrolling off the screen.
1963 See header of drivers/block/paride/pcd.c.
1964 See also Documentation/blockdev/paride.txt.
1966 pci=option[,option...] [PCI] various PCI subsystem options:
1967 earlydump [X86] dump PCI config space before the kernel
1969 off [X86] don't probe for the PCI bus
1970 bios [X86-32] force use of PCI BIOS, don't access
1971 the hardware directly. Use this if your machine
1972 has a non-standard PCI host bridge.
1973 nobios [X86-32] disallow use of PCI BIOS, only direct
1974 hardware access methods are allowed. Use this
1975 if you experience crashes upon bootup and you
1976 suspect they are caused by the BIOS.
1977 conf1 [X86] Force use of PCI Configuration
1979 conf2 [X86] Force use of PCI Configuration
1981 noaer [PCIE] If the PCIEAER kernel config parameter is
1982 enabled, this kernel boot option can be used to
1983 disable the use of PCIE advanced error reporting.
1984 nodomains [PCI] Disable support for multiple PCI
1985 root domains (aka PCI segments, in ACPI-speak).
1986 nommconf [X86] Disable use of MMCONFIG for PCI
1988 check_enable_amd_mmconf [X86] check for and enable
1989 properly configured MMIO access to PCI
1990 config space on AMD family 10h CPU
1991 nomsi [MSI] If the PCI_MSI kernel config parameter is
1992 enabled, this kernel boot option can be used to
1993 disable the use of MSI interrupts system-wide.
1994 noioapicquirk [APIC] Disable all boot interrupt quirks.
1995 Safety option to keep boot IRQs enabled. This
1996 should never be necessary.
1997 ioapicreroute [APIC] Enable rerouting of boot IRQs to the
1998 primary IO-APIC for bridges that cannot disable
1999 boot IRQs. This fixes a source of spurious IRQs
2000 when the system masks IRQs.
2001 noioapicreroute [APIC] Disable workaround that uses the
2002 boot IRQ equivalent of an IRQ that connects to
2003 a chipset where boot IRQs cannot be disabled.
2004 The opposite of ioapicreroute.
2005 biosirq [X86-32] Use PCI BIOS calls to get the interrupt
2006 routing table. These calls are known to be buggy
2007 on several machines and they hang the machine
2008 when used, but on other computers it's the only
2009 way to get the interrupt routing table. Try
2010 this option if the kernel is unable to allocate
2011 IRQs or discover secondary PCI buses on your
2013 rom [X86] Assign address space to expansion ROMs.
2014 Use with caution as certain devices share
2015 address decoders between ROMs and other
2017 norom [X86] Do not assign address space to
2018 expansion ROMs that do not already have
2019 BIOS assigned address ranges.
2020 nobar [X86] Do not assign address space to the
2021 BARs that weren't assigned by the BIOS.
2022 irqmask=0xMMMM [X86] Set a bit mask of IRQs allowed to be
2023 assigned automatically to PCI devices. You can
2024 make the kernel exclude IRQs of your ISA cards
2026 pirqaddr=0xAAAAA [X86] Specify the physical address
2027 of the PIRQ table (normally generated
2028 by the BIOS) if it is outside the
2029 F0000h-100000h range.
2030 lastbus=N [X86] Scan all buses thru bus #N. Can be
2031 useful if the kernel is unable to find your
2032 secondary buses and you want to tell it
2033 explicitly which ones they are.
2034 assign-busses [X86] Always assign all PCI bus
2035 numbers ourselves, overriding
2036 whatever the firmware may have done.
2037 usepirqmask [X86] Honor the possible IRQ mask stored
2038 in the BIOS $PIR table. This is needed on
2039 some systems with broken BIOSes, notably
2040 some HP Pavilion N5400 and Omnibook XE3
2041 notebooks. This will have no effect if ACPI
2042 IRQ routing is enabled.
2043 noacpi [X86] Do not use ACPI for IRQ routing
2044 or for PCI scanning.
2045 use_crs [X86] Use PCI host bridge window information
2046 from ACPI. On BIOSes from 2008 or later, this
2047 is enabled by default. If you need to use this,
2048 please report a bug.
2049 nocrs [X86] Ignore PCI host bridge windows from ACPI.
2050 If you need to use this, please report a bug.
2051 routeirq Do IRQ routing for all PCI devices.
2052 This is normally done in pci_enable_device(),
2053 so this option is a temporary workaround
2054 for broken drivers that don't call it.
2055 skip_isa_align [X86] do not align io start addr, so can
2056 handle more pci cards
2057 firmware [ARM] Do not re-enumerate the bus but instead
2058 just use the configuration from the
2059 bootloader. This is currently used on
2060 IXP2000 systems where the bus has to be
2061 configured a certain way for adjunct CPUs.
2062 noearly [X86] Don't do any early type 1 scanning.
2063 This might help on some broken boards which
2064 machine check when some devices' config space
2065 is read. But various workarounds are disabled
2066 and some IOMMU drivers will not work.
2067 bfsort Sort PCI devices into breadth-first order.
2068 This sorting is done to get a device
2069 order compatible with older (<= 2.4) kernels.
2070 nobfsort Don't sort PCI devices into breadth-first order.
2071 cbiosize=nn[KMG] The fixed amount of bus space which is
2072 reserved for the CardBus bridge's IO window.
2073 The default value is 256 bytes.
2074 cbmemsize=nn[KMG] The fixed amount of bus space which is
2075 reserved for the CardBus bridge's memory
2076 window. The default value is 64 megabytes.
2079 [<order of align>@][<domain>:]<bus>:<slot>.<func>[; ...]
2080 Specifies alignment and device to reassign
2081 aligned memory resources.
2082 If <order of align> is not specified,
2083 PAGE_SIZE is used as alignment.
2084 PCI-PCI bridge can be specified, if resource
2085 windows need to be expanded.
2086 ecrc= Enable/disable PCIe ECRC (transaction layer
2087 end-to-end CRC checking).
2088 bios: Use BIOS/firmware settings. This is the
2092 realloc reallocate PCI resources if allocations done by BIOS
2095 pcie_aspm= [PCIE] Forcibly enable or disable PCIe Active State Power
2098 force Enable ASPM even on devices that claim not to support it.
2099 WARNING: Forcing ASPM on may cause system lockups.
2101 pcie_ports= [PCIE] PCIe ports handling:
2102 auto Ask the BIOS whether or not to use native PCIe services
2103 associated with PCIe ports (PME, hot-plug, AER). Use
2104 them only if that is allowed by the BIOS.
2105 native Use native PCIe services associated with PCIe ports
2107 compat Treat PCIe ports as PCI-to-PCI bridges, disable the PCIe
2110 pcie_pme= [PCIE,PM] Native PCIe PME signaling options:
2111 nomsi Do not use MSI for native PCIe PME signaling (this makes
2112 all PCIe root ports use INTx for all services).
2114 pcmv= [HW,PCMCIA] BadgePAD 4
2117 See Documentation/blockdev/paride.txt.
2119 pdcchassis= [PARISC,HW] Disable/Enable PDC Chassis Status codes at
2122 See arch/parisc/kernel/pdc_chassis.c
2124 percpu_alloc= Select which percpu first chunk allocator to use.
2125 Currently supported values are "embed" and "page".
2126 Archs may support subset or none of the selections.
2127 See comments in mm/percpu.c for details on each
2128 allocator. This parameter is primarily for debugging
2129 and performance comparison.
2132 See Documentation/blockdev/paride.txt.
2135 See Documentation/blockdev/paride.txt.
2137 pirq= [SMP,APIC] Manual mp-table setup
2138 See Documentation/x86/i386/IO-APIC.txt.
2140 plip= [PPT,NET] Parallel port network link
2141 Format: { parport<nr> | timid | 0 }
2142 See also Documentation/parport.txt.
2144 pmtmr= [X86] Manual setup of pmtmr I/O Port.
2145 Override pmtimer IOPort with a hex value.
2149 Enable PNP debug messages (depends on the
2150 CONFIG_PNP_DEBUG_MESSAGES option). Change at run-time
2151 via /sys/module/pnp/parameters/debug. We always show
2152 current resource usage; turning this on also shows
2153 possible settings and some assignment information.
2159 { on | off | curr | res | no-curr | no-res }
2162 [ISAPNP] Exclude IRQs for the autoconfiguration
2165 [ISAPNP] Exclude DMAs for the autoconfiguration
2167 pnp_reserve_io= [ISAPNP] Exclude I/O ports for the autoconfiguration
2168 Ranges are in pairs (I/O port base and size).
2171 [ISAPNP] Exclude memory regions for the
2173 Ranges are in pairs (memory base and size).
2175 ports= [IP_VS_FTP] IPVS ftp helper module
2177 Up to 8 (IP_VS_APP_MAX_PORTS) ports
2179 Format: <port>,<port>....
2181 print-fatal-signals=
2182 [KNL] debug: print fatal signals
2184 If enabled, warn about various signal handling
2185 related application anomalies: too many signals,
2186 too many POSIX.1 timers, fatal signals causing a
2189 If you hit the warning due to signal overflow,
2190 you might want to try "ulimit -i unlimited".
2194 printk.always_kmsg_dump=
2195 Trigger kmsg_dump for cases other than kernel oops or
2197 Format: <bool> (1/Y/y=enable, 0/N/n=disable)
2200 printk.time= Show timing data prefixed to each printk message line
2201 Format: <bool> (1/Y/y=enable, 0/N/n=disable)
2203 processor.max_cstate= [HW,ACPI]
2204 Limit processor to maximum C-state
2205 max_cstate=9 overrides any DMI blacklist limit.
2207 processor.nocst [HW,ACPI]
2208 Ignore the _CST method to determine C-states,
2209 instead using the legacy FADT method
2211 profile= [KNL] Enable kernel profiling via /proc/profile
2212 Format: [schedule,]<number>
2213 Param: "schedule" - profile schedule points.
2214 Param: <number> - step/bucket size as a power of 2 for
2215 statistical time based profiling.
2216 Param: "sleep" - profile D-state sleeping (millisecs).
2217 Requires CONFIG_SCHEDSTATS
2218 Param: "kvm" - profile VM exits.
2220 prompt_ramdisk= [RAM] List of RAM disks to prompt for floppy disk
2222 See Documentation/blockdev/ramdisk.txt.
2224 psmouse.proto= [HW,MOUSE] Highest PS2 mouse protocol extension to
2225 probe for; one of (bare|imps|exps|lifebook|any).
2226 psmouse.rate= [HW,MOUSE] Set desired mouse report rate, in reports
2228 psmouse.resetafter= [HW,MOUSE]
2229 Try to reset the device after so many bad packets
2232 [HW,MOUSE] Set desired mouse resolution, in dpi.
2233 psmouse.smartscroll=
2234 [HW,MOUSE] Controls Logitech smartscroll autorepeat.
2235 0 = disabled, 1 = enabled (default).
2237 pstore.backend= Specify the name of the pstore backend to use
2240 See Documentation/blockdev/paride.txt.
2243 [KNL] Number of legacy pty's. Overwrites compiled-in
2246 quiet [KNL] Disable most log messages
2251 See Documentation/md.txt.
2253 ramdisk_blocksize= [RAM]
2254 See Documentation/blockdev/ramdisk.txt.
2256 ramdisk_size= [RAM] Sizes of RAM disks in kilobytes
2257 See Documentation/blockdev/ramdisk.txt.
2259 rcupdate.blimit= [KNL,BOOT]
2260 Set maximum number of finished RCU callbacks to process
2263 rcupdate.qhimark= [KNL,BOOT]
2264 Set threshold of queued
2265 RCU callbacks over which batch limiting is disabled.
2267 rcupdate.qlowmark= [KNL,BOOT]
2268 Set threshold of queued RCU callbacks below which
2269 batch limiting is re-enabled.
2273 Run specified binary instead of /init from the ramdisk,
2274 used for early userspace startup. See initrd.
2276 reboot= [BUGS=X86-32,BUGS=ARM,BUGS=IA-64] Rebooting mode
2277 Format: <reboot_mode>[,<reboot_mode2>[,...]]
2278 See arch/*/kernel/reboot.c or arch/*/kernel/process.c
2281 [KNL, SMP] Set scheduler's default relax_domain_level.
2282 See Documentation/cgroups/cpusets.txt.
2284 reserve= [KNL,BUGS] Force the kernel to ignore some iomem area
2286 reservetop= [X86-32]
2288 Reserves a hole at the top of the kernel virtual
2293 Set the amount of memory to reserve for BIOS at
2294 the bottom of the address space.
2296 reset_devices [KNL] Force drivers to reset the underlying device
2297 during initialization.
2300 Specify the partition device for software suspend
2302 resume_offset= [SWSUSP]
2303 Specify the offset from the beginning of the partition
2304 given by "resume=" at which the swap header is located,
2305 in <PAGE_SIZE> units (needed only for swap files).
2306 See Documentation/power/swsusp-and-swap-files.txt
2308 resumedelay= [HIBERNATION] Delay (in seconds) to pause before attempting to
2309 read the resume files
2311 resumewait [HIBERNATION] Wait (indefinitely) for resume device to show up.
2312 Useful for devices that are detected asynchronously
2313 (e.g. USB and MMC devices).
2315 hibernate= [HIBERNATION]
2316 noresume Don't check if there's a hibernation image
2317 present during boot.
2318 nocompress Don't compress/decompress hibernation images.
2320 retain_initrd [RAM] Keep initrd memory after extraction
2322 rhash_entries= [KNL,NET]
2323 Set number of hash buckets for route cache
2325 riscom8= [HW,SERIAL]
2326 Format: <io_board1>[,<io_board2>[,...<io_boardN>]]
2328 ro [KNL] Mount root device read-only on boot
2330 root= [KNL] Root filesystem
2331 See name_to_dev_t comment in init/do_mounts.c.
2333 rootdelay= [KNL] Delay (in seconds) to pause before attempting to
2334 mount the root filesystem
2336 rootflags= [KNL] Set root filesystem mount option string
2338 rootfstype= [KNL] Set root filesystem type
2340 rootwait [KNL] Wait (indefinitely) for root device to show up.
2341 Useful for devices that are detected asynchronously
2342 (e.g. USB and MMC devices).
2344 rw [KNL] Mount root device read-write on boot
2346 S [KNL] Run init in single mode
2349 See drivers/net/irda/sa1100_ir.c.
2351 sbni= [NET] Granch SBNI12 leased line adapter
2353 sched_debug [KNL] Enables verbose scheduler debug messages.
2355 security= [SECURITY] Choose a security module to enable at boot.
2356 If this boot parameter is not specified, only the first
2357 security module asking for security registration will be
2358 loaded. An invalid security module name will be treated
2359 as if no module has been chosen.
2361 selinux= [SELINUX] Disable or enable SELinux at boot time.
2362 Format: { "0" | "1" }
2363 See security/selinux/Kconfig help text.
2366 Default value is set via kernel config option.
2367 If enabled at boot time, /selinux/disable can be used
2368 later to disable prior to initial policy load.
2370 apparmor= [APPARMOR] Disable or enable AppArmor at boot time
2371 Format: { "0" | "1" }
2372 See security/apparmor/Kconfig help text
2375 Default value is set via kernel config option.
2377 serialnumber [BUGS=X86-32]
2380 Maximal number of shapers.
2382 show_msr= [x86] show boot-time MSR settings
2383 Format: { <integer> }
2384 Show boot-time (BIOS-initialized) MSR settings.
2385 The parameter means the number of CPUs to show,
2386 for example 1 means boot CPU only.
2393 slub_debug[=options[,slabs]] [MM, SLUB]
2394 Enabling slub_debug allows one to determine the
2395 culprit if slab objects become corrupted. Enabling
2396 slub_debug can create guard zones around objects and
2397 may poison objects when not in use. Also tracks the
2398 last alloc / free. For more information see
2399 Documentation/vm/slub.txt.
2401 slub_max_order= [MM, SLUB]
2402 Determines the maximum allowed order for slabs.
2403 A high setting may cause OOMs due to memory
2404 fragmentation. For more information see
2405 Documentation/vm/slub.txt.
2407 slub_min_objects= [MM, SLUB]
2408 The minimum number of objects per slab. SLUB will
2409 increase the slab order up to slub_max_order to
2410 generate a sufficiently large slab able to contain
2411 the number of objects indicated. The higher the number
2412 of objects the smaller the overhead of tracking slabs
2413 and the less frequently locks need to be acquired.
2414 For more information see Documentation/vm/slub.txt.
2416 slub_min_order= [MM, SLUB]
2417 Determines the mininum page order for slabs. Must be
2418 lower than slub_max_order.
2419 For more information see Documentation/vm/slub.txt.
2421 slub_nomerge [MM, SLUB]
2422 Disable merging of slabs with similar size. May be
2423 necessary if there is some reason to distinguish
2424 allocs to different slabs. Debug options disable
2425 merging on their own.
2426 For more information see Documentation/vm/slub.txt.
2429 Format: <io1>[,<io2>[,...,<io8>]]
2431 smp-alt-once [X86-32,SMP] On a hotplug CPU system, only
2432 attempt to substitute SMP alternatives once at boot.
2434 smsc-ircc2.nopnp [HW] Don't use PNP to discover SMC devices
2435 smsc-ircc2.ircc_cfg= [HW] Device configuration I/O port
2436 smsc-ircc2.ircc_sir= [HW] SIR base I/O port
2437 smsc-ircc2.ircc_fir= [HW] FIR base I/O port
2438 smsc-ircc2.ircc_irq= [HW] IRQ line
2439 smsc-ircc2.ircc_dma= [HW] DMA channel
2440 smsc-ircc2.ircc_transceiver= [HW] Transceiver type:
2441 0: Toshiba Satellite 1800 (GP data pin select)
2442 1: Fast pin select (default)
2446 [KNL] Should the soft-lockup detector generate panics.
2449 sonypi.*= [HW] Sony Programmable I/O Control Device driver
2450 See Documentation/laptops/sonypi.txt
2452 specialix= [HW,SERIAL] Specialix multi-serial port adapter
2453 See Documentation/serial/specialix.txt.
2455 spia_io_base= [HW,MTD]
2461 Enabled the stack tracer on boot up.
2465 Set the STI (builtin display/keyboard on the HP-PARISC
2466 machines) console (graphic card) which should be used
2467 as the initial boot-console.
2468 See also comment in drivers/video/console/sticore.c.
2471 See comment in drivers/video/console/sticore.c.
2474 Format: bpp:<bpp1>[:<bpp2>[:<bpp3>...]]
2476 sunrpc.min_resvport=
2477 sunrpc.max_resvport=
2479 SunRPC servers often require that client requests
2480 originate from a privileged port (i.e. a port in the
2481 range 0 < portnr < 1024).
2482 An administrator who wishes to reserve some of these
2483 ports for other uses may adjust the range that the
2484 kernel's sunrpc client considers to be privileged
2485 using these two parameters to set the minimum and
2486 maximum port values.
2490 Control how the NFS server code allocates CPUs to
2491 service thread pools. Depending on how many NICs
2492 you have and where their interrupts are bound, this
2493 option will affect which CPUs will do NFS serving.
2494 Note: this parameter cannot be changed while the
2495 NFS server is running.
2497 auto the server chooses an appropriate mode
2498 automatically using heuristics
2499 global a single global pool contains all CPUs
2500 percpu one pool for each CPU
2501 pernode one pool for each NUMA node (equivalent
2502 to global on non-NUMA machines)
2504 sunrpc.tcp_slot_table_entries=
2505 sunrpc.udp_slot_table_entries=
2507 Sets the upper limit on the number of simultaneous
2508 RPC calls that can be sent from the client to a
2509 server. Increasing these values may allow you to
2510 improve throughput, but will also increase the
2511 amount of memory reserved for use by the client.
2514 [KNL] Enable accounting of swap in memory resource
2515 controller if no parameter or 1 is given or disable
2516 it if 0 is given (See Documentation/cgroups/memory.txt)
2518 swiotlb= [IA-64] Number of I/O TLB slabs
2522 sysfs.deprecated=0|1 [KNL]
2523 Enable/disable old style sysfs layout for old udev
2524 on older distributions. When this option is enabled
2525 very new udev will not work anymore. When this option
2526 is disabled (or CONFIG_SYSFS_DEPRECATED not compiled)
2527 in older udev will not work anymore.
2528 Default depends on CONFIG_SYSFS_DEPRECATED_V2 set in
2529 the kernel configuration.
2531 sysrq_always_enabled
2533 Ignore sysrq setting - this boot parameter will
2534 neutralize any effect of /proc/sys/kernel/sysrq.
2535 Useful for debugging.
2539 test_suspend= [SUSPEND]
2540 Specify "mem" (for Suspend-to-RAM) or "standby" (for
2541 standby suspend) as the system sleep state to briefly
2542 enter during system startup. The system is woken from
2543 this state using a wakeup-capable RTC alarm.
2545 thash_entries= [KNL,NET]
2546 Set number of hash buckets for TCP connection
2548 thermal.act= [HW,ACPI]
2549 -1: disable all active trip points in all thermal zones
2550 <degrees C>: override all lowest active trip points
2552 thermal.crt= [HW,ACPI]
2553 -1: disable all critical trip points in all thermal zones
2554 <degrees C>: override all critical trip points
2556 thermal.nocrt= [HW,ACPI]
2557 Set to disable actions on ACPI thermal zone
2558 critical and hot trip points.
2560 thermal.off= [HW,ACPI]
2561 1: disable ACPI thermal control
2563 thermal.psv= [HW,ACPI]
2564 -1: disable all passive trip points
2565 <degrees C>: override all passive trip points to this
2568 thermal.tzp= [HW,ACPI]
2569 Specify global default ACPI thermal zone polling rate
2570 <deci-seconds>: poll all this frequency
2571 0: no polling (default)
2574 Force threading of all interrupt handlers except those
2575 marked explicitely IRQF_NO_THREAD.
2579 Specify if the kernel should make use of the cpu
2580 topology information if the hardware supports this.
2581 The scheduler will make use of this information and
2582 e.g. base its process migration decisions on it.
2587 tpm_suspend_pcr=[HW,TPM]
2588 Format: integer pcr id
2589 Specify that at suspend time, the tpm driver
2590 should extend the specified pcr with zeros,
2591 as a workaround for some chips which fail to
2592 flush the last written pcr on TPM_SaveState.
2593 This will guarantee that all the other pcrs
2596 trace_buf_size=nn[KMG]
2597 [FTRACE] will set tracing buffer size.
2599 trace_event=[event-list]
2600 [FTRACE] Set and start specified trace events in order
2601 to facilitate early boot debugging.
2602 See also Documentation/trace/events.txt
2604 tsc= Disable clocksource stability checks for TSC.
2606 [x86] reliable: mark tsc clocksource as reliable, this
2607 disables clocksource verification at runtime, as well
2608 as the stability checks done at bootup. Used to enable
2609 high-resolution timer mode on older hardware, and in
2610 virtualized environment.
2611 [x86] noirqtime: Do not use TSC to do irq accounting.
2612 Used to run time disable IRQ_TIME_ACCOUNTING on any
2613 platforms where RDTSC is slow and this accounting
2616 turbografx.map[2|3]= [HW,JOY]
2617 TurboGraFX parallel port interface
2619 <port#>,<js1>,<js2>,<js3>,<js4>,<js5>,<js6>,<js7>
2620 See also Documentation/input/joystick-parport.txt
2622 udbg-immortal [PPC] When debugging early kernel crashes that
2623 happen after console_init() and before a proper
2624 console driver takes over, this boot options might
2625 help "seeing" what's going on.
2627 uhash_entries= [KNL,NET]
2628 Set number of hash buckets for UDP/UDP-Lite connections
2631 [USB] Ignore overcurrent events (default N).
2632 Some badly-designed motherboards generate lots of
2633 bogus events, for ports that aren't wired to
2634 anything. Set this parameter to avoid log spamming.
2635 Note that genuine overcurrent events won't be
2639 [X86] Cause panic on unknown NMI.
2641 usbcore.authorized_default=
2642 [USB] Default USB device authorization:
2643 (default -1 = authorized except for wireless USB,
2644 0 = not authorized, 1 = authorized)
2646 usbcore.autosuspend=
2647 [USB] The autosuspend time delay (in seconds) used
2648 for newly-detected USB devices (default 2). This
2649 is the time required before an idle device will be
2650 autosuspended. Devices for which the delay is set
2651 to a negative value won't be autosuspended at all.
2653 usbcore.usbfs_snoop=
2654 [USB] Set to log all usbfs traffic (default 0 = off).
2656 usbcore.blinkenlights=
2657 [USB] Set to cycle leds on hubs (default 0 = off).
2659 usbcore.old_scheme_first=
2660 [USB] Start with the old device initialization
2661 scheme (default 0 = off).
2663 usbcore.use_both_schemes=
2664 [USB] Try the other device initialization scheme
2665 if the first one fails (default 1 = enabled).
2667 usbcore.initial_descriptor_timeout=
2668 [USB] Specifies timeout for the initial 64-byte
2669 USB_REQ_GET_DESCRIPTOR request in milliseconds
2670 (default 5000 = 5.0 seconds).
2673 [USBHID] The interval which mice are to be polled at.
2675 usb-storage.delay_use=
2676 [UMS] The delay in seconds before a new device is
2677 scanned for Logical Units (default 5).
2680 [UMS] A list of quirks entries to supplement or
2681 override the built-in unusual_devs list. List
2682 entries are separated by commas. Each entry has
2683 the form VID:PID:Flags where VID and PID are Vendor
2684 and Product ID values (4-digit hex numbers) and
2685 Flags is a set of characters, each corresponding
2686 to a common usb-storage quirk flag as follows:
2687 a = SANE_SENSE (collect more than 18 bytes
2689 b = BAD_SENSE (don't collect more than 18
2690 bytes of sense data);
2691 c = FIX_CAPACITY (decrease the reported
2692 device capacity by one sector);
2693 d = NO_READ_DISC_INFO (don't use
2694 READ_DISC_INFO command);
2695 e = NO_READ_CAPACITY_16 (don't use
2696 READ_CAPACITY_16 command);
2697 h = CAPACITY_HEURISTICS (decrease the
2698 reported device capacity by one
2699 sector if the number is odd);
2700 i = IGNORE_DEVICE (don't bind to this
2702 l = NOT_LOCKABLE (don't try to lock and
2703 unlock ejectable media);
2704 m = MAX_SECTORS_64 (don't transfer more
2705 than 64 sectors = 32 KB at a time);
2706 n = INITIAL_READ10 (force a retry of the
2707 initial READ(10) command);
2708 o = CAPACITY_OK (accept the capacity
2709 reported by the device);
2710 r = IGNORE_RESIDUE (the device reports
2711 bogus residue values);
2712 s = SINGLE_LUN (the device has only one
2714 w = NO_WP_DETECT (don't test whether the
2715 medium is write-protected).
2716 Example: quirks=0419:aaf5:rl,0421:0433:rc
2718 user_debug= [KNL,ARM]
2720 See arch/arm/Kconfig.debug help text.
2721 1 - undefined instruction events
2723 4 - invalid data aborts
2726 Example: user_debug=31
2729 [X86] Flags controlling user PTE allocations.
2731 nohigh = do not allocate PTE pages in
2732 HIGHMEM regardless of setting
2736 vdso=2: enable compat VDSO (default with COMPAT_VDSO)
2737 vdso=1: enable VDSO (default)
2738 vdso=0: disable VDSO mapping
2741 vdso32=2: enable compat VDSO (default with COMPAT_VDSO)
2742 vdso32=1: enable 32-bit VDSO (default)
2743 vdso32=0: disable 32-bit VDSO mapping
2746 vector=percpu: enable percpu vector domain
2748 video= [FB] Frame buffer configuration
2749 See Documentation/fb/modedb.txt.
2751 vga= [BOOT,X86-32] Select a particular video mode
2752 See Documentation/x86/boot.txt and
2753 Documentation/svga.txt.
2754 Use vga=ask for menu.
2755 This is actually a boot loader parameter; the value is
2756 passed to the kernel using a special protocol.
2758 vmalloc=nn[KMG] [KNL,BOOT] Forces the vmalloc area to have an exact
2759 size of <nn>. This can be used to increase the
2760 minimum size (128MB on x86). It can also be used to
2761 decrease the size and leave more room for directly
2764 vmhalt= [KNL,S390] Perform z/VM CP command after system halt.
2767 vmpanic= [KNL,S390] Perform z/VM CP command after kernel panic.
2770 vmpoff= [KNL,S390] Perform z/VM CP command after power off.
2774 Controls the behavior of vsyscalls (i.e. calls to
2775 fixed addresses of 0xffffffffff600x00 from legacy
2776 code). Most statically-linked binaries and older
2777 versions of glibc use these calls. Because these
2778 functions are at fixed addresses, they make nice
2779 targets for exploits that can control RIP.
2781 emulate Vsyscalls turn into traps and are emulated
2784 native [default] Vsyscalls are native syscall
2786 This is a little bit faster than trapping
2787 and makes a few dynamic recompilers work
2788 better than they would in emulation mode.
2789 It also makes exploits much easier to write.
2791 none Vsyscalls don't work at all. This makes
2792 them quite hard to use for exploits but
2793 might break your system.
2795 vt.cur_default= [VT] Default cursor shape.
2796 Format: 0xCCBBAA, where AA, BB, and CC are the same as
2797 the parameters of the <Esc>[?A;B;Cc escape sequence;
2798 see VGA-softcursor.txt. Default: 2 = underline.
2800 vt.default_blu= [VT]
2801 Format: <blue0>,<blue1>,<blue2>,...,<blue15>
2802 Change the default blue palette of the console.
2803 This is a 16-member array composed of values
2806 vt.default_grn= [VT]
2807 Format: <green0>,<green1>,<green2>,...,<green15>
2808 Change the default green palette of the console.
2809 This is a 16-member array composed of values
2812 vt.default_red= [VT]
2813 Format: <red0>,<red1>,<red2>,...,<red15>
2814 Change the default red palette of the console.
2815 This is a 16-member array composed of values
2821 Set system-wide default UTF-8 mode for all tty's.
2822 Default is 1, i.e. UTF-8 mode is enabled for all
2823 newly opened terminals.
2825 vt.global_cursor_default=
2828 Set system-wide default for whether a cursor
2829 is shown on new VTs. Default is -1,
2830 i.e. cursors will be created by default unless
2831 overridden by individual drivers. 0 will hide
2832 cursors, 1 will display them.
2834 watchdog timers [HW,WDT] For information on watchdog timers,
2835 see Documentation/watchdog/watchdog-parameters.txt
2836 or other driver-specific files in the
2837 Documentation/watchdog/ directory.
2839 x2apic_phys [X86-64,APIC] Use x2apic physical mode instead of
2840 default x2apic cluster mode on platforms
2843 x86_mrst_timer= [X86-32,APBT]
2844 Choose timer option for x86 Moorestown MID platform.
2845 Two valid options are apbt timer only and lapic timer
2846 plus one apbt timer for broadcast timer.
2847 x86_mrst_timer=apbt_only | lapic_and_apbt
2849 xd= [HW,XT] Original XT pre-IDE (RLL encoded) disks.
2850 xd_geo= See header of drivers/block/xd.c.
2852 xen_emul_unplug= [HW,X86,XEN]
2853 Unplug Xen emulated devices
2854 Format: [unplug0,][unplug1]
2855 ide-disks -- unplug primary master IDE devices
2856 aux-ide-disks -- unplug non-primary-master IDE devices
2857 nics -- unplug network devices
2858 all -- unplug all emulated devices (NICs and IDE disks)
2859 unnecessary -- unplugging emulated devices is
2860 unnecessary even if the host did not respond to
2862 never -- do not unplug even if version check succeeds
2864 xirc2ps_cs= [NET,PCMCIA]
2866 <irq>,<irq_mask>,<io>,<full_duplex>,<do_sound>,<lockup_hack>[,<irq2>[,<irq3>[,<irq4>]]]
2868 ______________________________________________________________________
2872 Add more DRM drivers.
projects / linux-flexiantxendom0.git / blob