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, 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 s4_nohwsig prevents ACPI hardware signature from being
262 used during resume from hibernation.
263 old_ordering causes the ACPI 1.0 ordering of the _PTS
264 control method, with respect to putting devices into
265 low power states, to be enforced (the ACPI 2.0 ordering
266 of _PTS is used by default).
267 nonvs prevents the kernel from saving/restoring the
268 ACPI NVS memory during suspend/hibernation and resume.
269 sci_force_enable causes the kernel to set SCI_EN directly
270 on resume from S1/S3 (which is against the ACPI spec,
271 but some broken systems don't work without it).
273 acpi_use_timer_override [HW,ACPI]
274 Use timer override. For some broken Nvidia NF5 boards
275 that require a timer override, but don't have HPET
277 acpi_enforce_resources= [ACPI]
278 { strict | lax | no }
279 Check for resource conflicts between native drivers
280 and ACPI OperationRegions (SystemIO and SystemMemory
281 only). IO ports and memory declared in ACPI might be
282 used by the ACPI subsystem in arbitrary AML code and
283 can interfere with legacy drivers.
284 strict (default): access to resources claimed by ACPI
285 is denied; legacy drivers trying to access reserved
286 resources will fail to bind to device using them.
287 lax: access to resources claimed by ACPI is allowed;
288 legacy drivers trying to access reserved resources
289 will bind successfully but a warning message is logged.
290 no: ACPI OperationRegions are not marked as reserved,
291 no further checks are performed.
293 add_efi_memmap [EFI; X86] Include EFI memory map in
294 kernel's map of available physical RAM.
297 { off | try_unsupported }
298 off: disable AGP support
299 try_unsupported: try to drive unsupported chipsets
300 (may crash computer or cause data corruption)
303 See Documentation/sound/alsa/alsa-parameters.txt
306 Allow the default userspace alignment fault handler
307 behaviour to be specified. Bit 0 enables warnings,
308 bit 1 enables fixups, and bit 2 sends a segfault.
310 align_va_addr= [X86-64]
311 Align virtual addresses by clearing slice [14:12] when
312 allocating a VMA at process creation time. This option
313 gives you up to 3% performance improvement on AMD F15h
314 machines (where it is enabled by default) for a
315 CPU-intensive style benchmark, and it can vary highly in
316 a microbenchmark depending on workload and compiler.
318 32: only for 32-bit processes
319 64: only for 64-bit processes
320 on: enable for both 32- and 64-bit processes
321 off: disable for both 32- and 64-bit processes
323 amd_iommu= [HW,X86-64]
324 Pass parameters to the AMD IOMMU driver in the system.
326 fullflush - enable flushing of IO/TLB entries when
327 they are unmapped. Otherwise they are
328 flushed before they will be reused, which
330 off - do not initialize any AMD IOMMU found in
333 amijoy.map= [HW,JOY] Amiga joystick support
334 Map of devices attached to JOY0DAT and JOY1DAT
336 See also Documentation/input/joystick.txt
338 analog.map= [HW,JOY] Analog joystick and gamepad support
339 Specifies type or capabilities of an analog joystick
340 connected to one of 16 gameports
341 Format: <type1>,<type2>,..<type16>
344 Power management functions (SPARCstation-4/5 + deriv.)
346 Disable APC CPU standby support. SPARCstation-Fox does
347 not play well with APC CPU idle - disable it if you have
348 APC and your system crashes randomly.
350 apic= [APIC,X86-32] Advanced Programmable Interrupt Controller
351 Change the output verbosity whilst booting
352 Format: { quiet (default) | verbose | debug }
353 Change the amount of debugging information output
354 when initialising the APIC and IO-APIC components.
357 See Documentation/networking/ipv6.txt.
359 show_lapic= [APIC,X86] Advanced Programmable Interrupt Controller
360 Limit apic dumping. The parameter defines the maximal
361 number of local apics being dumped. Also it is possible
362 to set it to "all" by meaning -- no limit here.
363 Format: { 1 (default) | 2 | ... | all }.
364 The parameter valid if only apic=debug or
365 apic=verbose is specified.
366 Example: apic=debug show_lapic=all
368 apm= [APM] Advanced Power Management
369 See header of arch/x86/kernel/apm_32.c.
371 arcrimi= [HW,NET] ARCnet - "RIM I" (entirely mem-mapped) cards
372 Format: <io>,<irq>,<nodeID>
376 atarimouse= [HW,MOUSE] Atari Mouse
378 atkbd.extra= [HW] Enable extra LEDs and keys on IBM RapidAccess,
379 EzKey and similar keyboards
381 atkbd.reset= [HW] Reset keyboard during initialization
383 atkbd.set= [HW] Select keyboard code set
384 Format: <int> (2 = AT (default), 3 = PS/2)
386 atkbd.scroll= [HW] Enable scroll wheel on MS Office and similar
389 atkbd.softraw= [HW] Choose between synthetic and real raw mode
390 Format: <bool> (0 = real, 1 = synthetic (default))
392 atkbd.softrepeat= [HW]
393 Use software keyboard repeat
397 baycom_epp= [HW,AX25]
400 baycom_par= [HW,AX25] BayCom Parallel Port AX.25 Modem
402 See header of drivers/net/hamradio/baycom_par.c.
404 baycom_ser_fdx= [HW,AX25]
405 BayCom Serial Port AX.25 Modem (Full Duplex Mode)
406 Format: <io>,<irq>,<mode>[,<baud>]
407 See header of drivers/net/hamradio/baycom_ser_fdx.c.
409 baycom_ser_hdx= [HW,AX25]
410 BayCom Serial Port AX.25 Modem (Half Duplex Mode)
411 Format: <io>,<irq>,<mode>
412 See header of drivers/net/hamradio/baycom_ser_hdx.c.
414 boot_delay= Milliseconds to delay each printk during boot.
415 Values larger than 10 seconds (10000) are changed to
419 bootmem_debug [KNL] Enable bootmem allocator debug messages.
421 bttv.card= [HW,V4L] bttv (bt848 + bt878 based grabber cards)
422 bttv.radio= Most important insmod options are available as
424 bttv.pll= See Documentation/video4linux/bttv/Insmod-options
427 bulk_remove=off [PPC] This parameter disables the use of the pSeries
428 firmware feature for flushing multiple hpte entries
431 c101= [NET] Moxa C101 synchronous serial card
433 cachesize= [BUGS=X86-32] Override level 2 CPU cache size detection.
434 Sometimes CPU hardware bugs make them report the cache
435 size incorrectly. The kernel will attempt work arounds
436 to fix known problems, but for some CPUs it is not
437 possible to determine what the correct size should be.
438 This option provides an override for these situations.
441 [SECURITY] Disable capabilities. This would normally
442 be used only if an alternative security model is to be
443 configured. Potentially dangerous and should only be
444 used if you are entirely sure of the consequences.
446 ccw_timeout_log [S390]
447 See Documentation/s390/CommonIO for details.
449 cgroup_disable= [KNL] Disable a particular controller
450 Format: {name of the controller(s) to disable}
451 {Currently supported controllers - "memory"}
453 checkreqprot [SELINUX] Set initial checkreqprot flag value.
454 Format: { "0" | "1" }
455 See security/selinux/Kconfig help text.
456 0 -- check protection applied by kernel (includes
457 any implied execute protection).
458 1 -- check protection requested by application.
459 Default value is set via a kernel config option.
460 Value can be changed at runtime via
461 /selinux/checkreqprot.
464 See Documentation/s390/CommonIO for details.
466 clock= [BUGS=X86-32, HW] gettimeofday clocksource override.
468 Forces specified clocksource (if available) to be used
469 when calculating gettimeofday(). If specified
470 clocksource is not available, it defaults to PIT.
471 Format: { pit | tsc | cyclone | pmtmr }
473 clocksource= Override the default clocksource
475 Override the default clocksource and use the clocksource
476 with the name specified.
477 Some clocksource names to choose from, depending on
479 [all] jiffies (this is the base, fallback clocksource)
481 [ARM] imx_timer1,OSTS,netx_timer,mpu_timer2,
482 pxa_timer,timer3,32k_counter,timer0_1
484 [X86-32] pit,hpet,tsc;
485 scx200_hrt on Geode; cyclone on IBM x440
493 clearcpuid=BITNUM [X86]
494 Disable CPUID feature X for the kernel. See
495 arch/x86/include/asm/cpufeature.h for the valid bit
496 numbers. Note the Linux specific bits are not necessarily
497 stable over kernel options, but the vendor specific
499 Also note that user programs calling CPUID directly
500 or using the feature without checking anything
501 will still see it. This just prevents it from
502 being used by the kernel or shown in /proc/cpuinfo.
503 Also note the kernel might malfunction if you disable
506 cmo_free_hint= [PPC] Format: { yes | no }
507 Specify whether pages are marked as being inactive
508 when they are freed. This is used in CMO environments
509 to determine OS memory pressure for page stealing by
513 code_bytes [X86] How many bytes of object code to print
518 com20020= [HW,NET] ARCnet - COM20020 chipset
520 <io>[,<irq>[,<nodeID>[,<backplane>[,<ckp>[,<timeout>]]]]]
522 com90io= [HW,NET] ARCnet - COM90xx chipset (IO-mapped buffers)
526 ARCnet - COM90xx chipset (memory-mapped buffers)
527 Format: <io>[,<irq>[,<memstart>]]
529 condev= [HW,S390] console device
532 console= [KNL] Output console device and options.
534 tty<n> Use the virtual console device <n>.
538 Use the specified serial port. The options are of
539 the form "bbbbpnf", where "bbbb" is the baud rate,
540 "p" is parity ("n", "o", or "e"), "n" is number of
541 bits, and "f" is flow control ("r" for RTS or
542 omit it). Default is "9600n8".
544 See Documentation/serial-console.txt for more
546 Documentation/networking/netconsole.txt for an
549 uart[8250],io,<addr>[,options]
550 uart[8250],mmio,<addr>[,options]
551 Start an early, polled-mode console on the 8250/16550
552 UART at the specified I/O port or MMIO address,
553 switching to the matching ttyS device later. The
554 options are the same as for ttyS, above.
555 hvc<n> Use the hypervisor console device <n>. This is for
556 both Xen and PowerPC hypervisors.
558 If the device connected to the port is not a TTY but a braille
559 device, prepend "brl," before the device type, for instance
561 For now, only VisioBraille is supported.
563 consoleblank= [KNL] The console blank (screen saver) timeout in
564 seconds. Defaults to 10*60 = 10mins. A value of 0
565 disables the blank timer.
568 [KNL] Change the default value for
569 /proc/<pid>/coredump_filter.
570 See also Documentation/filesystems/proc.txt.
572 cpuidle.off=1 [CPU_IDLE]
573 disable the cpuidle sub-system
575 cpcihp_generic= [HW,PCI] Generic port I/O CompactPCI driver
577 <first_slot>,<last_slot>,<port>,<enum_bit>[,<debug>]
579 crashkernel=size[KMG][@offset[KMG]]
580 [KNL] Using kexec, Linux can switch to a 'crash kernel'
581 upon panic. This parameter reserves the physical
582 memory region [offset, offset + size] for that kernel
583 image. If '@offset' is omitted, then a suitable offset
584 is selected automatically. Check
585 Documentation/kdump/kdump.txt for further details.
587 crashkernel=range1:size1[,range2:size2,...][@offset]
588 [KNL] Same as above, but depends on the memory
589 in the running system. The syntax of range is
590 start-[end] where start and end are both
591 a memory unit (amount[KMG]). See also
592 Documentation/kdump/kdump.txt for an example.
597 cs89x0_media= [HW,NET]
598 Format: { rj45 | aui | bnc }
601 See header of drivers/s390/block/dasd_devmap.c.
603 db9.dev[2|3]= [HW,JOY] Multisystem joystick support via parallel port
604 (one device per port)
605 Format: <port#>,<type>
606 See also Documentation/input/joystick-parport.txt
608 ddebug_query= [KNL,DYNAMIC_DEBUG] Enable debug messages at early boot
609 time. See Documentation/dynamic-debug-howto.txt for
612 debug [KNL] Enable kernel debugging (events log level).
615 [KNL] verbose self-tests
617 Print debugging info while doing the locking API
619 We default to 0 (no extra messages), setting it to
620 1 will print _a lot_ more information - normally
621 only useful to kernel developers.
623 debug_objects [KNL] Enable object debugging
626 [KNL] Disable object debugging
628 debugpat [X86] Enable PAT debugging
630 decnet.addr= [HW,NET]
631 Format: <area>[,<node>]
632 See also Documentation/networking/decnet.txt.
635 [same as hugepagesz=] The size of the default
636 HugeTLB page size. This is the size represented by
637 the legacy /proc/ hugepages APIs, used for SHM, and
638 default size when mounting hugetlbfs filesystems.
639 Defaults to the default architecture's huge page size
643 Set number of hash buckets for dentry cache.
646 IO parameters + enable/disable command.
648 digiepca= [HW,SERIAL]
649 See drivers/char/README.epca and
650 Documentation/serial/digiepca.txt.
653 See Documentation/networking/ipv6.txt.
655 disable_ddw [PPC/PSERIES]
656 Disable Dynamic DMA Window support. Use this if
657 to workaround buggy firmware.
660 See Documentation/networking/ipv6.txt.
662 disable_mtrr_cleanup [X86]
663 The kernel tries to adjust MTRR layout from continuous
664 to discrete, to make X server driver able to add WB
665 entry later. This parameter disables that.
667 disable_mtrr_trim [X86, Intel and AMD only]
668 By default the kernel will trim any uncacheable
669 memory out of your available memory pool based on
670 MTRR settings. This parameter disables that behavior,
671 possibly causing your machine to run very slowly.
673 disable_timer_pin_1 [X86]
674 Disable PIN 1 of APIC timer
675 Can be useful to work around chipset bugs.
677 dma_debug=off If the kernel is compiled with DMA_API_DEBUG support,
678 this option disables the debugging code at boot.
680 dma_debug_entries=<number>
681 This option allows to tune the number of preallocated
682 entries for DMA-API debugging code. One entry is
683 required per DMA-API allocation. Use this if the
684 DMA-API debugging code disables itself because the
685 architectural default is too low.
687 dma_debug_driver=<driver_name>
688 With this option the DMA-API debugging driver
689 filter feature can be enabled at boot time. Just
690 pass the driver to filter for as the parameter.
691 The filter can be disabled or changed to another
692 driver later using sysfs.
696 earlycon= [KNL] Output early console device and options.
697 uart[8250],io,<addr>[,options]
698 uart[8250],mmio,<addr>[,options]
699 uart[8250],mmio32,<addr>[,options]
700 Start an early, polled-mode console on the 8250/16550
701 UART at the specified I/O port or MMIO address.
702 MMIO inter-register address stride is either 8-bit
703 (mmio) or 32-bit (mmio32).
704 The options are the same as for ttyS, above.
706 earlyprintk= [X86,SH,BLACKFIN]
709 earlyprintk=serial[,ttySn[,baudrate]]
710 earlyprintk=ttySn[,baudrate]
711 earlyprintk=dbgp[debugController#]
713 Append ",keep" to not disable it when the real console
716 Only vga or serial or usb debug port at a time.
718 Currently only ttyS0 and ttyS1 are supported.
720 Interaction with the standard serial driver is not
723 The VGA output is eventually overwritten by the real
726 The xen output can only be used by Xen PV guests.
728 ekgdboc= [X86,KGDB] Allow early kernel console debugging
731 This is designed to be used in conjunction with
732 the boot argument: earlyprintk=vga
735 Format: {"off" | "on" | "skip[mbr]"}
737 efi_no_storage_paranoia [EFI; X86]
738 Using this parameter you can use more than 50% of
739 your efi variable storage. Use this parameter only if
740 you are really sure that your UEFI does sane gc and
741 fulfills the spec otherwise your board may brick.
743 eisa_irq_edge= [PARISC,HW]
744 See header of drivers/parisc/eisa.c.
747 See comment before function elanfreq_setup() in
748 arch/x86/kernel/cpu/cpufreq/elanfreq.c.
751 Format: {"cfq" | "deadline" | "noop"}
752 See Documentation/block/cfq-iosched.txt and
753 Documentation/block/deadline-iosched.txt for details.
755 elfcorehdr=[size[KMG]@]offset[KMG] [IA64,PPC,SH,X86,S390]
756 Specifies physical address of start of kernel core
757 image elf header and optionally the size. Generally
758 kexec loader will pass this option to capture kernel.
759 See Documentation/kdump/kdump.txt for details.
761 enable_mtrr_cleanup [X86]
762 The kernel tries to adjust MTRR layout from continuous
763 to discrete, to make X server driver able to add WB
764 entry later. This parameter enables that.
766 enable_timer_pin_1 [X86]
767 Enable PIN 1 of APIC timer
768 Can be useful to work around chipset bugs
769 (in particular on some ATI chipsets).
770 The kernel tries to set a reasonable default.
772 enforcing [SELINUX] Set initial enforcing status.
774 See security/selinux/Kconfig help text.
775 0 -- permissive (log only, no denials).
776 1 -- enforcing (deny and log).
778 Value can be changed at runtime via /selinux/enforce.
781 Disable Error Record Serialization Table (ERST)
784 ether= [HW,NET] Ethernet cards parameters
785 This option is obsoleted by the "netdev=" option, which
786 has equivalent usage. See its documentation for details.
790 Permit 'security.evm' to be updated regardless of
791 current integrity status.
795 fail_make_request=[KNL]
796 General fault injection mechanism.
797 Format: <interval>,<probability>,<space>,<times>
798 See also Documentation/fault-injection/.
801 See Documentation/blockdev/floppy.txt.
803 force_pal_cache_flush
804 [IA-64] Avoid check_sal_cache_flush which may hang on
805 buggy SAL_CACHE_FLUSH implementations. Using this
806 parameter will force ia64_sal_cache_flush to call
807 ia64_pal_cache_flush instead of SAL_CACHE_FLUSH.
810 [FTRACE] will set and start the specified tracer
811 as early as possible in order to facilitate early
814 ftrace_dump_on_oops[=orig_cpu]
815 [FTRACE] will dump the trace buffers on oops.
816 If no parameter is passed, ftrace will dump
817 buffers of all CPUs, but if you pass orig_cpu, it will
818 dump only the buffer of the CPU that triggered the
821 ftrace_filter=[function-list]
822 [FTRACE] Limit the functions traced by the function
823 tracer at boot up. function-list is a comma separated
824 list of functions. This list can be changed at run
825 time by the set_ftrace_filter file in the debugfs
828 ftrace_notrace=[function-list]
829 [FTRACE] Do not trace the functions specified in
830 function-list. This list can be changed at run time
831 by the set_ftrace_notrace file in the debugfs
834 ftrace_graph_filter=[function-list]
835 [FTRACE] Limit the top level callers functions traced
836 by the function graph tracer at boot up.
837 function-list is a comma separated list of functions
838 that can be changed at run time by the
839 set_graph_function file in the debugfs tracing directory.
842 [HW,JOY] Multisystem joystick and NES/SNES/PSX pad
843 support via parallel port (up to 5 devices per port)
844 Format: <port#>,<pad1>,<pad2>,<pad3>,<pad4>,<pad5>
845 See also Documentation/input/joystick-parport.txt
849 gart_fix_e820= [X86_64] disable the fix e820 for K8 GART
853 gcov_persist= [GCOV] When non-zero (default), profiling data for
854 kernel modules is saved and remains accessible via
855 debugfs, even when the module is unloaded/reloaded.
856 When zero, profiling data is discarded and associated
857 debugfs files are removed at module unload time.
859 gpt [EFI] Forces disk with valid GPT signature but
860 invalid Protective MBR to be treated as GPT.
862 hashdist= [KNL,NUMA] Large hashes allocated during boot
863 are distributed across NUMA nodes. Defaults on
864 for 64-bit NUMA, off otherwise.
865 Format: 0 | 1 (for off | on)
867 hcl= [IA-64] SGI's Hardware Graph compatibility layer
869 hd= [EIDE] (E)IDE hard drive subsystem geometry
870 Format: <cyl>,<head>,<sect>
873 Disable Hardware Error Source Table (HEST) support;
874 corresponding firmware-first mode error processing
875 logic will be disabled.
877 highmem=nn[KMG] [KNL,BOOT] forces the highmem zone to have an exact
878 size of <nn>. This works even on boxes that have no
879 highmem otherwise. This also works to reduce highmem
880 size on bigger boxes.
882 highres= [KNL] Enable/disable high resolution timer mode.
883 Valid parameters: "on", "off"
887 See Documentation/isdn/README.HiSax.
891 hpet= [X86-32,HPET] option to control HPET usage
892 Format: { enable (default) | disable | force |
894 disable: disable HPET and use PIT instead
895 force: allow force enabled of undocumented chips (ICH4,
897 verbose: show contents of HPET registers during setup
899 hugepages= [HW,X86-32,IA-64] HugeTLB pages to allocate at boot.
900 hugepagesz= [HW,IA-64,PPC,X86-64] The size of the HugeTLB pages.
901 On x86-64 and powerpc, this option can be specified
902 multiple times interleaved with hugepages= to reserve
903 huge pages of different sizes. Valid pages sizes on
904 x86-64 are 2M (when the CPU supports "pse") and 1G
905 (when the CPU supports the "pdpe1gb" cpuinfo flag)
906 Note that 1GB pages can only be allocated at boot time
907 using hugepages= and not freed afterwards.
909 hvc_iucv= [S390] Number of z/VM IUCV hypervisor console (HVC)
910 terminal devices. Valid values: 0..8
911 hvc_iucv_allow= [S390] Comma-separated list of z/VM user IDs.
912 If specified, z/VM IUCV HVC accepts connections
913 from listed z/VM user IDs only.
916 Do not unregister boot console at start. This is only
917 useful for debugging when something happens in the window
918 between unregistering the boot console and initializing
921 i2c_bus= [HW] Override the default board specific I2C bus speed
922 or register an additional I2C bus that is not
923 registered from board initialization code.
927 i8042.debug [HW] Toggle i8042 debug mode
928 i8042.direct [HW] Put keyboard port into non-translated mode
929 i8042.dumbkbd [HW] Pretend that controller can only read data from
930 keyboard and cannot control its state
931 (Don't attempt to blink the leds)
932 i8042.noaux [HW] Don't check for auxiliary (== mouse) port
933 i8042.nokbd [HW] Don't check/create keyboard port
934 i8042.noloop [HW] Disable the AUX Loopback command while probing
936 i8042.nomux [HW] Don't check presence of an active multiplexing
938 i8042.nopnp [HW] Don't use ACPIPnP / PnPBIOS to discover KBD/AUX
940 i8042.notimeout [HW] Ignore timeout condition signalled by conroller
941 i8042.reset [HW] Reset the controller during init and cleanup
942 i8042.unlock [HW] Unlock (ignore) the keylock
946 i8k.ignore_dmi [HW] Continue probing hardware even if DMI data
947 indicates that the driver is running on unsupported
949 i8k.force [HW] Activate i8k driver even if SMM BIOS signature
950 does not match list of supported models.
952 [HW] Report power status in /proc/i8k
953 (disabled by default)
954 i8k.restricted [HW] Allow controlling fans only if SYS_ADMIN
957 i915.invert_brightness=
958 [DRM] Invert the sense of the variable that is used to
959 set the brightness of the panel backlight. Normally a
960 brightness value of 0 indicates backlight switched off,
961 and the maximum of the brightness value sets the backlight
962 to maximum brightness. If this parameter is set to 0
963 (default) and the machine requires it, or this parameter
964 is set to 1, a brightness value of 0 sets the backlight
965 to maximum brightness, and the maximum of the brightness
966 value switches the backlight off.
967 -1 -- never invert brightness
969 1 -- force brightness inversion
972 Format: <io>[,<membase>[,<icn_id>[,<icn_id2>]]]
974 ide-core.nodma= [HW] (E)IDE subsystem
975 Format: =0.0 to prevent dma on hda, =0.1 hdb =1.0 hdc
976 .vlb_clock .pci_clock .noflush .nohpa .noprobe .nowerr
977 .cdrom .chs .ignore_cable are additional options
978 See Documentation/ide/ide.txt.
980 ide-pci-generic.all-generic-ide [HW] (E)IDE subsystem
981 Claim all unknown PCI IDE storage controllers.
984 Format: idle=poll, idle=mwait, idle=halt, idle=nomwait
985 Poll forces a polling idle loop that can slightly
986 improve the performance of waking up a idle CPU, but
987 will use a lot of power and make the system run hot.
989 idle=mwait: On systems which support MONITOR/MWAIT but
990 the kernel chose to not use it because it doesn't save
991 as much power as a normal idle loop, use the
992 MONITOR/MWAIT idle loop anyways. Performance should be
993 the same as idle=poll.
994 idle=halt: Halt is forced to be used for CPU idle.
995 In such case C2/C3 won't be used again.
996 idle=nomwait: Disable mwait for CPU C-states
998 ignore_loglevel [KNL]
999 Ignore loglevel setting - this will print /all/
1000 kernel messages to the console. Useful for debugging.
1001 We also add it as printk module parameter, so users
1002 could change it dynamically, usually by
1003 /sys/module/printk/parameters/ignore_loglevel.
1005 ihash_entries= [KNL]
1006 Set number of hash buckets for inode cache.
1009 Format: { "0" | "1" }
1010 0 -- integrity auditing messages. (Default)
1011 1 -- enable informational integrity auditing messages.
1014 Format: { "sha1" | "md5" }
1018 Load a policy which meets the needs of the Trusted
1019 Computing Base. This means IMA will measure all
1020 programs exec'd, files mmap'd for exec, and all files
1021 opened for read by uid=0.
1025 Run specified binary instead of /sbin/init as init
1028 initcall_debug [KNL] Trace initcalls as they are executed. Useful
1029 for working out where the kernel is dying during
1032 initrd= [BOOT] Specify the location of the initial ramdisk
1034 inport.irq= [HW] Inport (ATI XL and Microsoft) busmouse driver
1037 intel_iommu= [DMAR] Intel IOMMU driver (DMAR) option
1039 Enable intel iommu driver.
1041 Disable intel iommu driver.
1042 igfx_off [Default Off]
1043 By default, gfx is mapped as normal device. If a gfx
1044 device has a dedicated DMAR unit, the DMAR unit is
1045 bypassed by not enabling DMAR with this option. In
1046 this case, gfx device will use physical address for
1049 With this option iommu will not optimize to look
1050 for io virtual address below 32-bit forcing dual
1051 address cycle on pci bus for cards supporting greater
1052 than 32-bit addressing. The default is to look
1053 for translation below 32-bit and if not available
1054 then look in the higher range.
1055 strict [Default Off]
1056 With this option on every unmap_single operation will
1057 result in a hardware IOTLB flush operation as opposed
1058 to batching them for performance.
1059 sp_off [Default Off]
1060 By default, super page will be supported if Intel IOMMU
1061 has the capability. With this option, super page will
1063 intremap= [X86-64, Intel-IOMMU]
1064 on enable Interrupt Remapping (default)
1065 off disable Interrupt Remapping
1066 nosid disable Source ID checking
1068 BIOS x2APIC opt-out request will be ignored
1072 iomem= Disable strict checking of access to MMIO memory
1073 strict regions from userspace.
1089 io7= [HW] IO7 for Marvel based alpha systems
1090 See comment before marvel_specify_io7 in
1091 arch/alpha/kernel/core_marvel.c.
1093 io_delay= [X86] I/O delay method
1095 Standard port 0x80 based delay
1097 Alternate port 0xed based delay (needed on some systems)
1099 Simple two microseconds delay
1104 See Documentation/filesystems/nfs/nfsroot.txt.
1106 ip2= [HW] Set IO/IRQ pairs for up to 4 IntelliPort boards
1107 See comment before ip2_setup() in
1108 drivers/char/ip2/ip2base.c.
1111 When an interrupt is not handled search all handlers
1112 for it. Intended to get systems with badly broken
1116 When an interrupt is not handled search all handlers
1117 for it. Also check all handlers each timer
1118 interrupt. Intended to get systems with badly broken
1122 Format: <RDP>,<reset>,<pci_scan>,<verbosity>
1124 isolcpus= [KNL,SMP] Isolate CPUs from the general scheduler.
1126 <cpu number>,...,<cpu number>
1128 <cpu number>-<cpu number>
1129 (must be a positive range in ascending order)
1131 <cpu number>,...,<cpu number>-<cpu number>
1133 This option can be used to specify one or more CPUs
1134 to isolate from the general SMP balancing and scheduling
1135 algorithms. You can move a process onto or off an
1136 "isolated" CPU via the CPU affinity syscalls or cpuset.
1137 <cpu number> begins at 0 and the maximum value is
1138 "number of CPUs in system - 1".
1140 This option is the preferred way to isolate CPUs. The
1141 alternative -- manually setting the CPU mask of all
1142 tasks in the system -- can cause problems and
1143 suboptimal load balancer performance.
1147 js= [HW,JOY] Analog joystick
1148 See Documentation/input/joystick.txt.
1152 kernelcore=nn[KMG] [KNL,X86,IA-64,PPC] This parameter
1153 specifies the amount of memory usable by the kernel
1154 for non-movable allocations. The requested amount is
1155 spread evenly throughout all nodes in the system. The
1156 remaining memory in each node is used for Movable
1157 pages. In the event, a node is too small to have both
1158 kernelcore and Movable pages, kernelcore pages will
1159 take priority and other nodes will have a larger number
1160 of kernelcore pages. The Movable zone is used for the
1161 allocation of pages that may be reclaimed or moved
1162 by the page migration subsystem. This means that
1163 HugeTLB pages may not be allocated from this zone.
1164 Note that allocations like PTEs-from-HighMem still
1165 use the HighMem zone if it exists, and the Normal
1166 zone if it does not.
1168 kgdbdbgp= [KGDB,HW] kgdb over EHCI usb debug port.
1169 Format: <Controller#>[,poll interval]
1170 The controller # is the number of the ehci usb debug
1171 port as it is probed via PCI. The poll interval is
1172 optional and is the number seconds in between
1173 each poll cycle to the debug port in case you need
1174 the functionality for interrupting the kernel with
1175 gdb or control-c on the dbgp connection. When
1176 not using this parameter you use sysrq-g to break into
1177 the kernel debugger.
1179 kgdboc= [KGDB,HW] kgdb over consoles.
1180 Requires a tty driver that supports console polling,
1181 or a supported polling keyboard driver (non-usb).
1182 Serial only format: <serial_device>[,baud]
1183 keyboard only format: kbd
1184 keyboard and serial format: kbd,<serial_device>[,baud]
1185 Optional Kernel mode setting:
1186 kms, kbd format: kms,kbd
1187 kms, kbd and serial format: kms,kbd,<ser_dev>[,baud]
1189 kgdbwait [KGDB] Stop kernel execution and enter the
1190 kernel debugger at the earliest opportunity.
1192 kmac= [MIPS] korina ethernet MAC address.
1193 Configure the RouterBoard 532 series on-chip
1194 Ethernet adapter MAC address.
1196 kmemleak= [KNL] Boot-time kmemleak enable/disable
1197 Valid arguments: on, off
1200 kstack=N [X86] Print N words from the kernel stack
1203 kvm.ignore_msrs=[KVM] Ignore guest accesses to unhandled MSRs.
1204 Default is 0 (don't ignore, but inject #GP)
1206 kvm.oos_shadow= [KVM] Disable out-of-sync shadow paging.
1207 Default is 1 (enabled)
1209 kvm.mmu_audit= [KVM] This is a R/W parameter which allows audit
1213 kvm-amd.nested= [KVM,AMD] Allow nested virtualization in KVM/SVM.
1214 Default is 1 (enabled)
1216 kvm-amd.npt= [KVM,AMD] Disable nested paging (virtualized MMU)
1218 Default is 1 (enabled) if in 64-bit or 32-bit PAE mode.
1220 kvm-intel.ept= [KVM,Intel] Disable extended page tables
1221 (virtualized MMU) support on capable Intel chips.
1222 Default is 1 (enabled)
1224 kvm-intel.emulate_invalid_guest_state=
1225 [KVM,Intel] Enable emulation of invalid guest states
1226 Default is 0 (disabled)
1228 kvm-intel.flexpriority=
1229 [KVM,Intel] Disable FlexPriority feature (TPR shadow).
1230 Default is 1 (enabled)
1233 [KVM,Intel] Enable VMX nesting (nVMX).
1234 Default is 0 (disabled)
1236 kvm-intel.unrestricted_guest=
1237 [KVM,Intel] Disable unrestricted guest feature
1238 (virtualized real and unpaged mode) on capable
1239 Intel chips. Default is 1 (enabled)
1241 kvm-intel.vpid= [KVM,Intel] Disable Virtual Processor Identification
1242 feature (tagged TLBs) on capable Intel chips.
1243 Default is 1 (enabled)
1249 lapic [X86-32,APIC] Enable the local APIC even if BIOS
1252 lapic_timer_c2_ok [X86,APIC] trust the local apic timer
1255 libata.dma= [LIBATA] DMA control
1256 libata.dma=0 Disable all PATA and SATA DMA
1257 libata.dma=1 PATA and SATA Disk DMA only
1258 libata.dma=2 ATAPI (CDROM) DMA only
1259 libata.dma=4 Compact Flash DMA only
1260 Combinations also work, so libata.dma=3 enables DMA
1261 for disks and CDROMs, but not CFs.
1263 libata.ignore_hpa= [LIBATA] Ignore HPA limit
1264 libata.ignore_hpa=0 keep BIOS limits (default)
1265 libata.ignore_hpa=1 ignore limits, using full disk
1267 libata.noacpi [LIBATA] Disables use of ACPI in libata suspend/resume
1271 libata.force= [LIBATA] Force configurations. The format is comma
1272 separated list of "[ID:]VAL" where ID is
1273 PORT[.DEVICE]. PORT and DEVICE are decimal numbers
1274 matching port, link or device. Basically, it matches
1275 the ATA ID string printed on console by libata. If
1276 the whole ID part is omitted, the last PORT and DEVICE
1277 values are used. If ID hasn't been specified yet, the
1278 configuration applies to all ports, links and devices.
1280 If only DEVICE is omitted, the parameter applies to
1281 the port and all links and devices behind it. DEVICE
1282 number of 0 either selects the first device or the
1283 first fan-out link behind PMP device. It does not
1284 select the host link. DEVICE number of 15 selects the
1285 host link and device attached to it.
1287 The VAL specifies the configuration to force. As long
1288 as there's no ambiguity shortcut notation is allowed.
1289 For example, both 1.5 and 1.5G would work for 1.5Gbps.
1290 The following configurations can be forced.
1292 * Cable type: 40c, 80c, short40c, unk, ign or sata.
1293 Any ID with matching PORT is used.
1295 * SATA link speed limit: 1.5Gbps or 3.0Gbps.
1297 * Transfer mode: pio[0-7], mwdma[0-4] and udma[0-7].
1298 udma[/][16,25,33,44,66,100,133] notation is also
1301 * [no]ncq: Turn on or off NCQ.
1303 * nohrst, nosrst, norst: suppress hard, soft
1306 * dump_id: dump IDENTIFY data.
1308 * disable: Disable this device.
1310 If there are multiple matching configurations changing
1311 the same attribute, the last one is used.
1313 memblock=debug [KNL] Enable memblock debug messages.
1315 load_ramdisk= [RAM] List of ramdisks to load from floppy
1316 See Documentation/blockdev/ramdisk.txt.
1318 lockd.nlm_grace_period=P [NFS] Assign grace period.
1321 lockd.nlm_tcpport=N [NFS] Assign TCP port.
1324 lockd.nlm_timeout=T [NFS] Assign timeout value.
1327 lockd.nlm_udpport=M [NFS] Assign UDP port.
1330 logibm.irq= [HW,MOUSE] Logitech Bus Mouse Driver
1333 loglevel= All Kernel Messages with a loglevel smaller than the
1334 console loglevel will be printed to the console. It can
1335 also be changed with klogd or other programs. The
1336 loglevels are defined as follows:
1338 0 (KERN_EMERG) system is unusable
1339 1 (KERN_ALERT) action must be taken immediately
1340 2 (KERN_CRIT) critical conditions
1341 3 (KERN_ERR) error conditions
1342 4 (KERN_WARNING) warning conditions
1343 5 (KERN_NOTICE) normal but significant condition
1344 6 (KERN_INFO) informational
1345 7 (KERN_DEBUG) debug-level messages
1347 log_buf_len=n[KMG] Sets the size of the printk ring buffer,
1348 in bytes. n must be a power of two. The default
1349 size is set in the kernel config file.
1351 logo.nologo [FB] Disables display of the built-in Linux logo.
1352 This may be used to provide more screen space for
1353 kernel log messages and is useful when debugging
1354 kernel boot problems.
1356 lp=0 [LP] Specify parallel ports to use, e.g,
1357 lp=port[,port...] lp=none,parport0 (lp0 not configured, lp1 uses
1358 lp=reset first parallel port). 'lp=0' disables the
1359 lp=auto printer driver. 'lp=reset' (which can be
1360 specified in addition to the ports) causes
1361 attached printers to be reset. Using
1362 lp=port1,port2,... specifies the parallel ports
1363 to associate lp devices with, starting with
1364 lp0. A port specification may be 'none' to skip
1365 that lp device, or a parport name such as
1366 'parport0'. Specifying 'lp=auto' instead of a
1367 port specification list means that device IDs
1368 from each port should be examined, to see if
1369 an IEEE 1284-compliant printer is attached; if
1370 so, the driver will manage that printer.
1371 See also header of drivers/char/lp.c.
1374 Sets loops_per_jiffy to given constant, thus avoiding
1375 time-consuming boot-time autodetection (up to 250 ms per
1376 CPU). 0 enables autodetection (default). To determine
1377 the correct value for your kernel, boot with normal
1378 autodetection and see what value is printed. Note that
1379 on SMP systems the preset will be applied to all CPUs,
1380 which is likely to cause problems if your CPUs need
1381 significantly divergent settings. An incorrect value
1382 will cause delays in the kernel to be wrong, leading to
1383 unpredictable I/O errors and other breakage. Although
1384 unlikely, in the extreme case this might damage your
1388 Format: <io>,<irq>,<dma>
1390 machvec= [IA-64] Force the use of a particular machine-vector
1391 (machvec) in a generic kernel.
1392 Example: machvec=hpzx1_swiotlb
1394 machtype= [Loongson] Share the same kernel image file between different
1396 Example: machtype=lemote-yeeloong-2f-7inch
1398 max_addr=nn[KMG] [KNL,BOOT,ia64] All physical memory greater
1399 than or equal to this physical address is ignored.
1401 maxcpus= [SMP] Maximum number of processors that an SMP kernel
1402 should make use of. maxcpus=n : n >= 0 limits the
1403 kernel to using 'n' processors. n=0 is a special case,
1404 it is equivalent to "nosmp", which also disables
1407 max_loop= [LOOP] The number of loop block devices that get
1408 (loop.max_loop) unconditionally pre-created at init time. The default
1409 number is configured by BLK_DEV_LOOP_MIN_COUNT. Instead
1410 of statically allocating a predefined number, loop
1411 devices can be requested on-demand with the
1412 /dev/loop-control interface.
1416 mce [X86-32] Machine Check Exception
1418 mce=option [X86-64] See Documentation/x86/x86_64/boot-options.txt
1420 md= [HW] RAID subsystems devices and level
1421 See Documentation/md.txt.
1424 Format: <first>,<last>
1425 Specifies range of consoles to be captured by the MDA.
1427 mem=nn[KMG] [KNL,BOOT] Force usage of a specific amount of memory
1428 Amount of memory to be used when the kernel is not able
1429 to see the whole system memory or for test.
1430 [X86-32] Use together with memmap= to avoid physical
1431 address space collisions. Without memmap= PCI devices
1432 could be placed at addresses belonging to unused RAM.
1434 mem=nopentium [BUGS=X86-32] Disable usage of 4MB pages for kernel
1438 [KNL,SH] Allow user to override the default size for
1439 per-device physically contiguous DMA buffers.
1441 memmap=exactmap [KNL,X86] Enable setting of an exact
1442 E820 memory map, as specified by the user.
1443 Such memmap=exactmap lines can be constructed based on
1444 BIOS output or other requirements. See the memmap=nn@ss
1447 memmap=nn[KMG]@ss[KMG]
1448 [KNL] Force usage of a specific region of memory
1449 Region of memory to be used, from ss to ss+nn.
1451 memmap=nn[KMG]#ss[KMG]
1452 [KNL,ACPI] Mark specific memory as ACPI data.
1453 Region of memory to be used, from ss to ss+nn.
1455 memmap=nn[KMG]$ss[KMG]
1456 [KNL,ACPI] Mark specific memory as reserved.
1457 Region of memory to be used, from ss to ss+nn.
1458 Example: Exclude memory from 0x18690000-0x1869ffff
1459 memmap=64K$0x18690000
1461 memmap=0x10000$0x18690000
1463 memory_corruption_check=0/1 [X86]
1464 Some BIOSes seem to corrupt the first 64k of
1465 memory when doing things like suspend/resume.
1466 Setting this option will scan the memory
1467 looking for corruption. Enabling this will
1468 both detect corruption and prevent the kernel
1469 from using the memory being corrupted.
1470 However, its intended as a diagnostic tool; if
1471 repeatable BIOS-originated corruption always
1472 affects the same memory, you can use memmap=
1473 to prevent the kernel from using that memory.
1475 memory_corruption_check_size=size [X86]
1476 By default it checks for corruption in the low
1477 64k, making this memory unavailable for normal
1478 use. Use this parameter to scan for
1479 corruption in more or less memory.
1481 memory_corruption_check_period=seconds [X86]
1482 By default it checks for corruption every 60
1483 seconds. Use this parameter to check at some
1484 other rate. 0 disables periodic checking.
1486 memtest= [KNL,X86] Enable memtest
1488 default : 0 <disable>
1489 Specifies the number of memtest passes to be
1490 performed. Each pass selects another test
1491 pattern from a given set of patterns. Memtest
1492 fills the memory with this pattern, validates
1493 memory contents and reserves bad memory
1494 regions that are detected.
1496 meye.*= [HW] Set MotionEye Camera parameters
1497 See Documentation/video4linux/meye.txt.
1499 mfgpt_irq= [IA-32] Specify the IRQ to use for the
1500 Multi-Function General Purpose Timers on AMD Geode
1503 mfgptfix [X86-32] Fix MFGPT timers on AMD Geode platforms when
1504 the BIOS has incorrectly applied a workaround. TinyBIOS
1505 version 0.98 is known to be affected, 0.99 fixes the
1506 problem by letting the user disable the workaround.
1510 min_addr=nn[KMG] [KNL,BOOT,ia64] All physical memory below this
1511 physical address is ignored.
1513 mini2440= [ARM,HW,KNL]
1514 Format:[0..2][b][c][t]
1516 MINI2440 configuration specification:
1517 0 - The attached screen is the 3.5" TFT
1518 1 - The attached screen is the 7" TFT
1519 2 - The VGA Shield is attached (1024x768)
1520 Leaving out the screen size parameter will not load
1521 the TFT driver, and the framebuffer will be left
1523 b - Enable backlight. The TFT backlight pin will be
1524 linked to the kernel VESA blanking code and a GPIO
1525 LED. This parameter is not necessary when using the
1527 c - Enable the s3c camera interface.
1528 t - Reserved for enabling touchscreen support. The
1529 touchscreen support is not enabled in the mainstream
1530 kernel as of 2.6.30, a preliminary port can be found
1531 in the "bleeding edge" mini2440 support kernel at
1532 http://repo.or.cz/w/linux-2.6/mini2440.git
1535 [KNL] When CONFIG_DEBUG_MEMORY_INIT is set, this
1536 parameter allows control of the logging verbosity for
1537 the additional memory initialisation checks. A value
1538 of 0 disables mminit logging and a level of 4 will
1539 log everything. Information is printed at KERN_DEBUG
1540 so loglevel=8 may also need to be specified.
1543 [MOUSE] Maximum time between finger touching and
1544 leaving touchpad surface for touch to be considered
1545 a tap and be reported as a left button click (for
1546 touchpads working in absolute mode only).
1548 mousedev.xres= [MOUSE] Horizontal screen resolution, used for devices
1549 reporting absolute coordinates, such as tablets
1550 mousedev.yres= [MOUSE] Vertical screen resolution, used for devices
1551 reporting absolute coordinates, such as tablets
1553 movablecore=nn[KMG] [KNL,X86,IA-64,PPC] This parameter
1554 is similar to kernelcore except it specifies the
1555 amount of memory used for migratable allocations.
1556 If both kernelcore and movablecore is specified,
1557 then kernelcore will be at *least* the specified
1558 value but may be more. If movablecore on its own
1559 is specified, the administrator must be careful
1560 that the amount of memory usable for all allocations
1563 MTD_Partition= [MTD]
1564 Format: <name>,<region-number>,<size>,<offset>
1566 MTD_Region= [MTD] Format:
1567 <name>,<region-number>[,<base>,<size>,<buswidth>,<altbuswidth>]
1570 See drivers/mtd/cmdlinepart.c.
1572 multitce=off [PPC] This parameter disables the use of the pSeries
1573 firmware feature for updating multiple TCE entries
1576 onenand.bdry= [HW,MTD] Flex-OneNAND Boundary Configuration
1578 Format: [die0_boundary][,die0_lock][,die1_boundary][,die1_lock]
1580 boundary - index of last SLC block on Flex-OneNAND.
1581 The remaining blocks are configured as MLC blocks.
1582 lock - Configure if Flex-OneNAND boundary should be locked.
1583 Once locked, the boundary cannot be changed.
1584 1 indicates lock status, 0 indicates unlock status.
1587 ARM/S3C2412 JIVE boot control
1589 See arch/arm/mach-s3c2412/mach-jive.c
1591 mtouchusb.raw_coordinates=
1592 [HW] Make the MicroTouch USB driver use raw coordinates
1593 ('y', default) or cooked coordinates ('n')
1595 mtrr_chunk_size=nn[KMG] [X86]
1596 used for mtrr cleanup. It is largest continuous chunk
1597 that could hold holes aka. UC entries.
1599 mtrr_gran_size=nn[KMG] [X86]
1600 Used for mtrr cleanup. It is granularity of mtrr block.
1602 Large value could prevent small alignment from
1605 mtrr_spare_reg_nr=n [X86]
1607 Range: 0,7 : spare reg number
1609 Used for mtrr cleanup. It is spare mtrr entries number.
1610 Set to 2 or more if your graphical card needs more.
1612 n2= [NET] SDL Inc. RISCom/N2 synchronous serial card
1614 netdev= [NET] Network devices parameters
1615 Format: <irq>,<io>,<mem_start>,<mem_end>,<name>
1616 Note that mem_start is often overloaded to mean
1617 something different and driver-specific.
1618 This usage is only documented in each driver source
1622 [NETFILTER] Enable connection tracking flow accounting
1623 0 to disable accounting
1624 1 to enable accounting
1627 nfsaddrs= [NFS] Deprecated. Use ip= instead.
1628 See Documentation/filesystems/nfs/nfsroot.txt.
1630 nfsroot= [NFS] nfs root filesystem for disk-less boxes.
1631 See Documentation/filesystems/nfs/nfsroot.txt.
1633 nfsrootdebug [NFS] enable nfsroot debugging messages.
1634 See Documentation/filesystems/nfs/nfsroot.txt.
1636 nfs.callback_tcpport=
1637 [NFS] set the TCP port on which the NFSv4 callback
1638 channel should listen.
1641 [NFS] sets the pathname to the program which is used
1642 to update the NFS client cache entries.
1644 nfs.cache_getent_timeout=
1645 [NFS] sets the timeout after which an attempt to
1646 update a cache entry is deemed to have failed.
1648 nfs.idmap_cache_timeout=
1649 [NFS] set the maximum lifetime for idmapper cache
1653 [NFS] enable 64-bit inode numbers.
1654 If zero, the NFS client will fake up a 32-bit inode
1655 number for the readdir() and stat() syscalls instead
1656 of returning the full 64-bit number.
1657 The default is to return 64-bit inode numbers.
1659 nfs.nfs4_disable_idmapping=
1660 [NFSv4] When set, this option disables the NFSv4
1661 idmapper on the client, but only if the mount
1662 is using the 'sec=sys' security flavour. This may
1663 make migration from legacy NFSv2/v3 systems easier
1664 provided that the server has the appropriate support.
1665 The default is to always enable NFSv4 idmapping.
1667 nmi_debug= [KNL,AVR32,SH] Specify one or more actions to take
1668 when a NMI is triggered.
1669 Format: [state][,regs][,debounce][,die]
1671 nmi_watchdog= [KNL,BUGS=X86] Debugging features for SMP kernels
1672 Format: [panic,][nopanic,][num]
1674 0 - turn nmi_watchdog off
1675 When panic is specified, panic when an NMI watchdog
1676 timeout occurs (or 'nopanic' to override the opposite
1678 This is useful when you use a panic=... timeout and
1679 need the box quickly up again.
1681 netpoll.carrier_timeout=
1682 [NET] Specifies amount of time (in seconds) that
1683 netpoll should wait for a carrier. By default netpoll
1686 no387 [BUGS=X86-32] Tells the kernel to use the 387 maths
1687 emulation library even if a 387 maths coprocessor
1691 [HW] Never suspend the console
1692 Disable suspending of consoles during suspend and
1693 hibernate operations. Once disabled, debugging
1694 messages can reach various consoles while the rest
1695 of the system is being put to sleep (ie, while
1696 debugging driver suspend/resume hooks). This may
1697 not work reliably with all consoles, but is known
1698 to work with serial and VGA consoles.
1699 To facilitate more flexible debugging, we also add
1700 console_suspend, a printk module parameter to control
1701 it. Users could use console_suspend (usually
1702 /sys/module/printk/parameters/console_suspend) to
1703 turn on/off it dynamically.
1705 noaliencache [MM, NUMA, SLAB] Disables the allocation of alien
1706 caches in the slab allocator. Saves per-node memory,
1707 but will impact performance.
1711 noapic [SMP,APIC] Tells the kernel to not make use of any
1712 IOAPICs that may be present in the system.
1714 noautogroup Disable scheduler automatic task group creation.
1716 nobats [PPC] Do not use BATs for mapping kernel lowmem
1717 on "Classic" PPC cores.
1721 noclflush [BUGS=X86] Don't use the CLFLUSH instruction
1723 nodelayacct [KNL] Disable per-task delay accounting
1725 nodisconnect [HW,SCSI,M68K] Disables SCSI disconnects.
1727 nodsp [SH] Disable hardware DSP at boot time.
1729 noefi [X86] Disable EFI runtime services support.
1734 On X86-32 available only on PAE configured kernels.
1735 noexec=on: enable non-executable mappings (default)
1736 noexec=off: disable non-executable mappings
1739 Disable SMEP (Supervisor Mode Execution Protection)
1740 even if it is supported by processor.
1743 This affects only 32-bit executables.
1744 noexec32=on: enable non-executable mappings (default)
1745 read doesn't imply executable mappings
1746 noexec32=off: disable non-executable mappings
1747 read implies executable mappings
1749 nofpu [SH] Disable hardware FPU at boot time.
1751 nofxsr [BUGS=X86-32] Disables x86 floating point extended
1752 register save and restore. The kernel will only save
1753 legacy floating-point registers on task switch.
1755 noxsave [BUGS=X86] Disables x86 extended register state save
1756 and restore using xsave. The kernel will fallback to
1757 enabling legacy floating-point and sse state.
1759 nohlt [BUGS=ARM,SH] Tells the kernel that the sleep(SH) or
1760 wfi(ARM) instruction doesn't work correctly and not to
1761 use it. This is also useful when using JTAG debugger.
1763 no-hlt [BUGS=X86-32] Tells the kernel that the hlt
1764 instruction doesn't work correctly and not to
1767 no_file_caps Tells the kernel not to honor file capabilities. The
1768 only way then for a file to be executed with privilege
1769 is to be setuid root or executed by root.
1771 nohalt [IA-64] Tells the kernel not to use the power saving
1772 function PAL_HALT_LIGHT when idle. This increases
1773 power-consumption. On the positive side, it reduces
1774 interrupt wake-up latency, which may improve performance
1775 in certain environments such as networked servers or
1778 nohz= [KNL] Boottime enable/disable dynamic ticks
1779 Valid arguments: on, off
1782 noiotrap [SH] Disables trapped I/O port accesses.
1784 noirqdebug [X86-32] Disables the code which attempts to detect and
1785 disable unhandled interrupt sources.
1787 no_timer_check [X86,APIC] Disables the code which tests for
1788 broken timer IRQ sources.
1790 noisapnp [ISAPNP] Disables ISA PnP code.
1792 noinitrd [RAM] Tells the kernel not to load any configured
1795 nointremap [X86-64, Intel-IOMMU] Do not enable interrupt
1797 [Deprecated - use intremap=off]
1801 nojitter [IA-64] Disables jitter checking for ITC timers.
1803 no-kvmclock [X86,KVM] Disable paravirtualized KVM clock driver
1805 no-kvmapf [X86,KVM] Disable paravirtualized asynchronous page
1808 no-steal-acc [X86,KVM] Disable paravirtualized steal time accounting.
1809 steal time is computed, but won't influence scheduler
1812 nolapic [X86-32,APIC] Do not enable or use the local APIC.
1814 nolapic_timer [X86-32,APIC] Do not use the local APIC timer.
1816 noltlbs [PPC] Do not use large page/tlb entries for kernel
1817 lowmem mapping on PPC40x.
1819 nomca [IA-64] Disable machine check abort handling
1821 nomce [X86-32] Machine Check Exception
1823 nomfgpt [X86-32] Disable Multi-Function General Purpose
1824 Timer usage (for AMD Geode machines).
1826 nopat [X86] Disable PAT (page attribute table extension of
1827 pagetables) support.
1829 norandmaps Don't use address space randomization. Equivalent to
1830 echo 0 > /proc/sys/kernel/randomize_va_space
1832 noreplace-paravirt [X86,IA-64,PV_OPS] Don't patch paravirt_ops
1834 noreplace-smp [X86-32,SMP] Don't replace SMP instructions
1835 with UP alternatives
1837 noresidual [PPC] Don't use residual data on PReP machines.
1839 nordrand [X86] Disable the direct use of the RDRAND
1840 instruction even if it is supported by the
1841 processor. RDRAND is still available to user
1844 noresume [SWSUSP] Disables resume and restores original swap
1847 no-scroll [VGA] Disables scrollback.
1848 This is required for the Braillex ib80-piezo Braille
1849 reader made by F.H. Papenmeier (Germany).
1853 nosep [BUGS=X86-32] Disables x86 SYSENTER/SYSEXIT support.
1855 nosmp [SMP] Tells an SMP kernel to act as a UP kernel,
1856 and disable the IO APIC. legacy for "maxcpus=0".
1858 nosoftlockup [KNL] Disable the soft-lockup detector.
1860 nosync [HW,M68K] Disables sync negotiation for all devices.
1862 notsc [BUGS=X86-32] Disable Time Stamp Counter
1864 nousb [USB] Disable the USB subsystem
1866 nowatchdog [KNL] Disable the lockup detector (NMI watchdog).
1870 nox2apic [X86-64,APIC] Do not enable x2APIC mode.
1872 nptcg= [IA-64] Override max number of concurrent global TLB
1873 purges which is reported from either PAL_VM_SUMMARY or
1876 nr_cpus= [SMP] Maximum number of processors that an SMP kernel
1877 could support. nr_cpus=n : n >= 1 limits the kernel to
1878 supporting 'n' processors. Later in runtime you can not
1879 use hotplug cpu feature to put more cpu back to online.
1880 just like you compile the kernel NR_CPUS=n
1882 nr_uarts= [SERIAL] maximum number of UARTs to be registered.
1884 numa_zonelist_order= [KNL, BOOT] Select zonelist order for NUMA.
1885 one of ['zone', 'node', 'default'] can be specified
1886 This can be set from sysctl after boot.
1887 See Documentation/sysctl/vm.txt for details.
1889 ohci1394_dma=early [HW] enable debugging via the ohci1394 driver.
1890 See Documentation/debugging-via-ohci1394.txt for more
1893 olpc_ec_timeout= [OLPC] ms delay when issuing EC commands
1894 Rather than timing out after 20 ms if an EC
1895 command is not properly ACKed, override the length
1896 of the timeout. We have interrupts disabled while
1897 waiting for the ACK, so if this is set too high
1898 interrupts *may* be lost!
1900 omap_mux= [OMAP] Override bootloader pin multiplexing.
1901 Format: <mux_mode0.mode_name=value>...
1902 For example, to override I2C bus2:
1903 omap_mux=i2c2_scl.i2c2_scl=0x100,i2c2_sda.i2c2_sda=0x100
1905 oprofile.timer= [HW]
1906 Use timer interrupt instead of performance counters
1908 oprofile.cpu_type= Force an oprofile cpu type
1909 This might be useful if you have an older oprofile
1910 userland or if you want common events.
1911 Format: { arch_perfmon }
1912 arch_perfmon: [X86] Force use of architectural
1913 perfmon on Intel CPUs instead of the
1914 CPU specific event set.
1916 oops=panic Always panic on oopses. Default is to just kill the
1917 process, but there is a small probability of
1918 deadlocking the machine.
1919 This will also cause panics on machine check exceptions.
1920 Useful together with panic=30 to trigger a reboot.
1923 See Documentation/sound/oss/oss-parameters.txt
1925 panic= [KNL] Kernel behaviour on panic: delay <timeout>
1926 timeout > 0: seconds before rebooting
1927 timeout = 0: wait forever
1928 timeout < 0: reboot immediately
1931 parkbd.port= [HW] Parallel port number the keyboard adapter is
1932 connected to, default is 0.
1934 parkbd.mode= [HW] Parallel port keyboard adapter mode of operation,
1935 0 for XT, 1 for AT (default is AT).
1938 parport= [HW,PPT] Specify parallel ports. 0 disables.
1939 Format: { 0 | auto | 0xBBB[,IRQ[,DMA]] }
1940 Use 'auto' to force the driver to use any
1941 IRQ/DMA settings detected (the default is to
1942 ignore detected IRQ/DMA settings because of
1943 possible conflicts). You can specify the base
1944 address, IRQ, and DMA settings; IRQ and DMA
1945 should be numbers, or 'auto' (for using detected
1946 settings on that particular port), or 'nofifo'
1947 (to avoid using a FIFO even if it is detected).
1948 Parallel ports are assigned in the order they
1949 are specified on the command line, starting
1952 parport_init_mode= [HW,PPT]
1953 Configure VIA parallel port to operate in
1954 a specific mode. This is necessary on Pegasos
1955 computer where firmware has no options for setting
1956 up parallel port mode and sets it to spp.
1957 Currently this function knows 686a and 8231 chips.
1958 Format: [spp|ps2|epp|ecp|ecpepp]
1961 Halt all CPUs after the first oops has been printed for
1962 the specified number of seconds. This is to be used if
1963 your oopses keep scrolling off the screen.
1968 See header of drivers/block/paride/pcd.c.
1969 See also Documentation/blockdev/paride.txt.
1971 pci=option[,option...] [PCI] various PCI subsystem options:
1972 earlydump [X86] dump PCI config space before the kernel
1974 off [X86] don't probe for the PCI bus
1975 bios [X86-32] force use of PCI BIOS, don't access
1976 the hardware directly. Use this if your machine
1977 has a non-standard PCI host bridge.
1978 nobios [X86-32] disallow use of PCI BIOS, only direct
1979 hardware access methods are allowed. Use this
1980 if you experience crashes upon bootup and you
1981 suspect they are caused by the BIOS.
1982 conf1 [X86] Force use of PCI Configuration
1984 conf2 [X86] Force use of PCI Configuration
1986 noaer [PCIE] If the PCIEAER kernel config parameter is
1987 enabled, this kernel boot option can be used to
1988 disable the use of PCIE advanced error reporting.
1989 nodomains [PCI] Disable support for multiple PCI
1990 root domains (aka PCI segments, in ACPI-speak).
1991 nommconf [X86] Disable use of MMCONFIG for PCI
1993 check_enable_amd_mmconf [X86] check for and enable
1994 properly configured MMIO access to PCI
1995 config space on AMD family 10h CPU
1996 nomsi [MSI] If the PCI_MSI kernel config parameter is
1997 enabled, this kernel boot option can be used to
1998 disable the use of MSI interrupts system-wide.
1999 noioapicquirk [APIC] Disable all boot interrupt quirks.
2000 Safety option to keep boot IRQs enabled. This
2001 should never be necessary.
2002 ioapicreroute [APIC] Enable rerouting of boot IRQs to the
2003 primary IO-APIC for bridges that cannot disable
2004 boot IRQs. This fixes a source of spurious IRQs
2005 when the system masks IRQs.
2006 noioapicreroute [APIC] Disable workaround that uses the
2007 boot IRQ equivalent of an IRQ that connects to
2008 a chipset where boot IRQs cannot be disabled.
2009 The opposite of ioapicreroute.
2010 biosirq [X86-32] Use PCI BIOS calls to get the interrupt
2011 routing table. These calls are known to be buggy
2012 on several machines and they hang the machine
2013 when used, but on other computers it's the only
2014 way to get the interrupt routing table. Try
2015 this option if the kernel is unable to allocate
2016 IRQs or discover secondary PCI buses on your
2018 rom [X86] Assign address space to expansion ROMs.
2019 Use with caution as certain devices share
2020 address decoders between ROMs and other
2022 norom [X86] Do not assign address space to
2023 expansion ROMs that do not already have
2024 BIOS assigned address ranges.
2025 nobar [X86] Do not assign address space to the
2026 BARs that weren't assigned by the BIOS.
2027 irqmask=0xMMMM [X86] Set a bit mask of IRQs allowed to be
2028 assigned automatically to PCI devices. You can
2029 make the kernel exclude IRQs of your ISA cards
2031 pirqaddr=0xAAAAA [X86] Specify the physical address
2032 of the PIRQ table (normally generated
2033 by the BIOS) if it is outside the
2034 F0000h-100000h range.
2035 lastbus=N [X86] Scan all buses thru bus #N. Can be
2036 useful if the kernel is unable to find your
2037 secondary buses and you want to tell it
2038 explicitly which ones they are.
2039 assign-busses [X86] Always assign all PCI bus
2040 numbers ourselves, overriding
2041 whatever the firmware may have done.
2042 usepirqmask [X86] Honor the possible IRQ mask stored
2043 in the BIOS $PIR table. This is needed on
2044 some systems with broken BIOSes, notably
2045 some HP Pavilion N5400 and Omnibook XE3
2046 notebooks. This will have no effect if ACPI
2047 IRQ routing is enabled.
2048 noacpi [X86] Do not use ACPI for IRQ routing
2049 or for PCI scanning.
2050 use_crs [X86] Use PCI host bridge window information
2051 from ACPI. On BIOSes from 2008 or later, this
2052 is enabled by default. If you need to use this,
2053 please report a bug.
2054 nocrs [X86] Ignore PCI host bridge windows from ACPI.
2055 If you need to use this, please report a bug.
2056 routeirq Do IRQ routing for all PCI devices.
2057 This is normally done in pci_enable_device(),
2058 so this option is a temporary workaround
2059 for broken drivers that don't call it.
2060 skip_isa_align [X86] do not align io start addr, so can
2061 handle more pci cards
2062 firmware [ARM] Do not re-enumerate the bus but instead
2063 just use the configuration from the
2064 bootloader. This is currently used on
2065 IXP2000 systems where the bus has to be
2066 configured a certain way for adjunct CPUs.
2067 noearly [X86] Don't do any early type 1 scanning.
2068 This might help on some broken boards which
2069 machine check when some devices' config space
2070 is read. But various workarounds are disabled
2071 and some IOMMU drivers will not work.
2072 bfsort Sort PCI devices into breadth-first order.
2073 This sorting is done to get a device
2074 order compatible with older (<= 2.4) kernels.
2075 nobfsort Don't sort PCI devices into breadth-first order.
2076 cbiosize=nn[KMG] The fixed amount of bus space which is
2077 reserved for the CardBus bridge's IO window.
2078 The default value is 256 bytes.
2079 cbmemsize=nn[KMG] The fixed amount of bus space which is
2080 reserved for the CardBus bridge's memory
2081 window. The default value is 64 megabytes.
2084 [<order of align>@][<domain>:]<bus>:<slot>.<func>[; ...]
2085 Specifies alignment and device to reassign
2086 aligned memory resources.
2087 If <order of align> is not specified,
2088 PAGE_SIZE is used as alignment.
2089 PCI-PCI bridge can be specified, if resource
2090 windows need to be expanded.
2091 ecrc= Enable/disable PCIe ECRC (transaction layer
2092 end-to-end CRC checking).
2093 bios: Use BIOS/firmware settings. This is the
2097 realloc reallocate PCI resources if allocations done by BIOS
2100 pcie_aspm= [PCIE] Forcibly enable or disable PCIe Active State Power
2103 force Enable ASPM even on devices that claim not to support it.
2104 WARNING: Forcing ASPM on may cause system lockups.
2106 pcie_ports= [PCIE] PCIe ports handling:
2107 auto Ask the BIOS whether or not to use native PCIe services
2108 associated with PCIe ports (PME, hot-plug, AER). Use
2109 them only if that is allowed by the BIOS.
2110 native Use native PCIe services associated with PCIe ports
2112 compat Treat PCIe ports as PCI-to-PCI bridges, disable the PCIe
2115 pcie_pme= [PCIE,PM] Native PCIe PME signaling options:
2116 nomsi Do not use MSI for native PCIe PME signaling (this makes
2117 all PCIe root ports use INTx for all services).
2119 pcmv= [HW,PCMCIA] BadgePAD 4
2122 See Documentation/blockdev/paride.txt.
2124 pdcchassis= [PARISC,HW] Disable/Enable PDC Chassis Status codes at
2127 See arch/parisc/kernel/pdc_chassis.c
2129 percpu_alloc= Select which percpu first chunk allocator to use.
2130 Currently supported values are "embed" and "page".
2131 Archs may support subset or none of the selections.
2132 See comments in mm/percpu.c for details on each
2133 allocator. This parameter is primarily for debugging
2134 and performance comparison.
2137 See Documentation/blockdev/paride.txt.
2140 See Documentation/blockdev/paride.txt.
2142 pirq= [SMP,APIC] Manual mp-table setup
2143 See Documentation/x86/i386/IO-APIC.txt.
2145 plip= [PPT,NET] Parallel port network link
2146 Format: { parport<nr> | timid | 0 }
2147 See also Documentation/parport.txt.
2149 pmtmr= [X86] Manual setup of pmtmr I/O Port.
2150 Override pmtimer IOPort with a hex value.
2154 Enable PNP debug messages (depends on the
2155 CONFIG_PNP_DEBUG_MESSAGES option). Change at run-time
2156 via /sys/module/pnp/parameters/debug. We always show
2157 current resource usage; turning this on also shows
2158 possible settings and some assignment information.
2164 { on | off | curr | res | no-curr | no-res }
2167 [ISAPNP] Exclude IRQs for the autoconfiguration
2170 [ISAPNP] Exclude DMAs for the autoconfiguration
2172 pnp_reserve_io= [ISAPNP] Exclude I/O ports for the autoconfiguration
2173 Ranges are in pairs (I/O port base and size).
2176 [ISAPNP] Exclude memory regions for the
2178 Ranges are in pairs (memory base and size).
2180 ports= [IP_VS_FTP] IPVS ftp helper module
2182 Up to 8 (IP_VS_APP_MAX_PORTS) ports
2184 Format: <port>,<port>....
2186 print-fatal-signals=
2187 [KNL] debug: print fatal signals
2189 If enabled, warn about various signal handling
2190 related application anomalies: too many signals,
2191 too many POSIX.1 timers, fatal signals causing a
2194 If you hit the warning due to signal overflow,
2195 you might want to try "ulimit -i unlimited".
2199 printk.time= Show timing data prefixed to each printk message line
2200 Format: <bool> (1/Y/y=enable, 0/N/n=disable)
2202 processor.max_cstate= [HW,ACPI]
2203 Limit processor to maximum C-state
2204 max_cstate=9 overrides any DMI blacklist limit.
2206 processor.nocst [HW,ACPI]
2207 Ignore the _CST method to determine C-states,
2208 instead using the legacy FADT method
2210 profile= [KNL] Enable kernel profiling via /proc/profile
2211 Format: [schedule,]<number>
2212 Param: "schedule" - profile schedule points.
2213 Param: <number> - step/bucket size as a power of 2 for
2214 statistical time based profiling.
2215 Param: "sleep" - profile D-state sleeping (millisecs).
2216 Requires CONFIG_SCHEDSTATS
2217 Param: "kvm" - profile VM exits.
2219 prompt_ramdisk= [RAM] List of RAM disks to prompt for floppy disk
2221 See Documentation/blockdev/ramdisk.txt.
2223 psmouse.proto= [HW,MOUSE] Highest PS2 mouse protocol extension to
2224 probe for; one of (bare|imps|exps|lifebook|any).
2225 psmouse.rate= [HW,MOUSE] Set desired mouse report rate, in reports
2227 psmouse.resetafter= [HW,MOUSE]
2228 Try to reset the device after so many bad packets
2231 [HW,MOUSE] Set desired mouse resolution, in dpi.
2232 psmouse.smartscroll=
2233 [HW,MOUSE] Controls Logitech smartscroll autorepeat.
2234 0 = disabled, 1 = enabled (default).
2236 pstore.backend= Specify the name of the pstore backend to use
2239 See Documentation/blockdev/paride.txt.
2242 [KNL] Number of legacy pty's. Overwrites compiled-in
2245 quiet [KNL] Disable most log messages
2250 See Documentation/md.txt.
2252 ramdisk_blocksize= [RAM]
2253 See Documentation/blockdev/ramdisk.txt.
2255 ramdisk_size= [RAM] Sizes of RAM disks in kilobytes
2256 See Documentation/blockdev/ramdisk.txt.
2258 rcupdate.blimit= [KNL,BOOT]
2259 Set maximum number of finished RCU callbacks to process
2262 rcupdate.qhimark= [KNL,BOOT]
2263 Set threshold of queued
2264 RCU callbacks over which batch limiting is disabled.
2266 rcupdate.qlowmark= [KNL,BOOT]
2267 Set threshold of queued RCU callbacks below which
2268 batch limiting is re-enabled.
2272 Run specified binary instead of /init from the ramdisk,
2273 used for early userspace startup. See initrd.
2275 reboot= [BUGS=X86-32,BUGS=ARM,BUGS=IA-64] Rebooting mode
2276 Format: <reboot_mode>[,<reboot_mode2>[,...]]
2277 See arch/*/kernel/reboot.c or arch/*/kernel/process.c
2280 [KNL, SMP] Set scheduler's default relax_domain_level.
2281 See Documentation/cgroups/cpusets.txt.
2283 reserve= [KNL,BUGS] Force the kernel to ignore some iomem area
2285 reservetop= [X86-32]
2287 Reserves a hole at the top of the kernel virtual
2292 Set the amount of memory to reserve for BIOS at
2293 the bottom of the address space.
2295 reset_devices [KNL] Force drivers to reset the underlying device
2296 during initialization.
2299 Specify the partition device for software suspend
2301 resume_offset= [SWSUSP]
2302 Specify the offset from the beginning of the partition
2303 given by "resume=" at which the swap header is located,
2304 in <PAGE_SIZE> units (needed only for swap files).
2305 See Documentation/power/swsusp-and-swap-files.txt
2307 resumedelay= [HIBERNATION] Delay (in seconds) to pause before attempting to
2308 read the resume files
2310 resumewait [HIBERNATION] Wait (indefinitely) for resume device to show up.
2311 Useful for devices that are detected asynchronously
2312 (e.g. USB and MMC devices).
2314 hibernate= [HIBERNATION]
2315 noresume Don't check if there's a hibernation image
2316 present during boot.
2317 nocompress Don't compress/decompress hibernation images.
2319 retain_initrd [RAM] Keep initrd memory after extraction
2321 rhash_entries= [KNL,NET]
2322 Set number of hash buckets for route cache
2324 riscom8= [HW,SERIAL]
2325 Format: <io_board1>[,<io_board2>[,...<io_boardN>]]
2327 ro [KNL] Mount root device read-only on boot
2329 root= [KNL] Root filesystem
2330 See name_to_dev_t comment in init/do_mounts.c.
2332 rootdelay= [KNL] Delay (in seconds) to pause before attempting to
2333 mount the root filesystem
2335 rootflags= [KNL] Set root filesystem mount option string
2337 rootfstype= [KNL] Set root filesystem type
2339 rootwait [KNL] Wait (indefinitely) for root device to show up.
2340 Useful for devices that are detected asynchronously
2341 (e.g. USB and MMC devices).
2343 rw [KNL] Mount root device read-write on boot
2345 S [KNL] Run init in single mode
2348 See drivers/net/irda/sa1100_ir.c.
2350 sbni= [NET] Granch SBNI12 leased line adapter
2352 sched_debug [KNL] Enables verbose scheduler debug messages.
2354 security= [SECURITY] Choose a security module to enable at boot.
2355 If this boot parameter is not specified, only the first
2356 security module asking for security registration will be
2357 loaded. An invalid security module name will be treated
2358 as if no module has been chosen.
2360 selinux= [SELINUX] Disable or enable SELinux at boot time.
2361 Format: { "0" | "1" }
2362 See security/selinux/Kconfig help text.
2365 Default value is set via kernel config option.
2366 If enabled at boot time, /selinux/disable can be used
2367 later to disable prior to initial policy load.
2369 apparmor= [APPARMOR] Disable or enable AppArmor at boot time
2370 Format: { "0" | "1" }
2371 See security/apparmor/Kconfig help text
2374 Default value is set via kernel config option.
2376 serialnumber [BUGS=X86-32]
2379 Maximal number of shapers.
2381 show_msr= [x86] show boot-time MSR settings
2382 Format: { <integer> }
2383 Show boot-time (BIOS-initialized) MSR settings.
2384 The parameter means the number of CPUs to show,
2385 for example 1 means boot CPU only.
2392 slub_debug[=options[,slabs]] [MM, SLUB]
2393 Enabling slub_debug allows one to determine the
2394 culprit if slab objects become corrupted. Enabling
2395 slub_debug can create guard zones around objects and
2396 may poison objects when not in use. Also tracks the
2397 last alloc / free. For more information see
2398 Documentation/vm/slub.txt.
2400 slub_max_order= [MM, SLUB]
2401 Determines the maximum allowed order for slabs.
2402 A high setting may cause OOMs due to memory
2403 fragmentation. For more information see
2404 Documentation/vm/slub.txt.
2406 slub_min_objects= [MM, SLUB]
2407 The minimum number of objects per slab. SLUB will
2408 increase the slab order up to slub_max_order to
2409 generate a sufficiently large slab able to contain
2410 the number of objects indicated. The higher the number
2411 of objects the smaller the overhead of tracking slabs
2412 and the less frequently locks need to be acquired.
2413 For more information see Documentation/vm/slub.txt.
2415 slub_min_order= [MM, SLUB]
2416 Determines the mininum page order for slabs. Must be
2417 lower than slub_max_order.
2418 For more information see Documentation/vm/slub.txt.
2420 slub_nomerge [MM, SLUB]
2421 Disable merging of slabs with similar size. May be
2422 necessary if there is some reason to distinguish
2423 allocs to different slabs. Debug options disable
2424 merging on their own.
2425 For more information see Documentation/vm/slub.txt.
2428 Format: <io1>[,<io2>[,...,<io8>]]
2430 smp-alt-once [X86-32,SMP] On a hotplug CPU system, only
2431 attempt to substitute SMP alternatives once at boot.
2433 smsc-ircc2.nopnp [HW] Don't use PNP to discover SMC devices
2434 smsc-ircc2.ircc_cfg= [HW] Device configuration I/O port
2435 smsc-ircc2.ircc_sir= [HW] SIR base I/O port
2436 smsc-ircc2.ircc_fir= [HW] FIR base I/O port
2437 smsc-ircc2.ircc_irq= [HW] IRQ line
2438 smsc-ircc2.ircc_dma= [HW] DMA channel
2439 smsc-ircc2.ircc_transceiver= [HW] Transceiver type:
2440 0: Toshiba Satellite 1800 (GP data pin select)
2441 1: Fast pin select (default)
2445 [KNL] Should the soft-lockup detector generate panics.
2448 sonypi.*= [HW] Sony Programmable I/O Control Device driver
2449 See Documentation/laptops/sonypi.txt
2451 specialix= [HW,SERIAL] Specialix multi-serial port adapter
2452 See Documentation/serial/specialix.txt.
2454 spia_io_base= [HW,MTD]
2460 Enabled the stack tracer on boot up.
2464 Set the STI (builtin display/keyboard on the HP-PARISC
2465 machines) console (graphic card) which should be used
2466 as the initial boot-console.
2467 See also comment in drivers/video/console/sticore.c.
2470 See comment in drivers/video/console/sticore.c.
2473 Format: bpp:<bpp1>[:<bpp2>[:<bpp3>...]]
2475 sunrpc.min_resvport=
2476 sunrpc.max_resvport=
2478 SunRPC servers often require that client requests
2479 originate from a privileged port (i.e. a port in the
2480 range 0 < portnr < 1024).
2481 An administrator who wishes to reserve some of these
2482 ports for other uses may adjust the range that the
2483 kernel's sunrpc client considers to be privileged
2484 using these two parameters to set the minimum and
2485 maximum port values.
2489 Control how the NFS server code allocates CPUs to
2490 service thread pools. Depending on how many NICs
2491 you have and where their interrupts are bound, this
2492 option will affect which CPUs will do NFS serving.
2493 Note: this parameter cannot be changed while the
2494 NFS server is running.
2496 auto the server chooses an appropriate mode
2497 automatically using heuristics
2498 global a single global pool contains all CPUs
2499 percpu one pool for each CPU
2500 pernode one pool for each NUMA node (equivalent
2501 to global on non-NUMA machines)
2503 sunrpc.tcp_slot_table_entries=
2504 sunrpc.udp_slot_table_entries=
2506 Sets the upper limit on the number of simultaneous
2507 RPC calls that can be sent from the client to a
2508 server. Increasing these values may allow you to
2509 improve throughput, but will also increase the
2510 amount of memory reserved for use by the client.
2513 [KNL] Enable accounting of swap in memory resource
2514 controller if no parameter or 1 is given or disable
2515 it if 0 is given (See Documentation/cgroups/memory.txt)
2517 swiotlb= [IA-64] Number of I/O TLB slabs
2521 sysfs.deprecated=0|1 [KNL]
2522 Enable/disable old style sysfs layout for old udev
2523 on older distributions. When this option is enabled
2524 very new udev will not work anymore. When this option
2525 is disabled (or CONFIG_SYSFS_DEPRECATED not compiled)
2526 in older udev will not work anymore.
2527 Default depends on CONFIG_SYSFS_DEPRECATED_V2 set in
2528 the kernel configuration.
2530 sysrq_always_enabled
2532 Ignore sysrq setting - this boot parameter will
2533 neutralize any effect of /proc/sys/kernel/sysrq.
2534 Useful for debugging.
2538 test_suspend= [SUSPEND]
2539 Specify "mem" (for Suspend-to-RAM) or "standby" (for
2540 standby suspend) as the system sleep state to briefly
2541 enter during system startup. The system is woken from
2542 this state using a wakeup-capable RTC alarm.
2544 thash_entries= [KNL,NET]
2545 Set number of hash buckets for TCP connection
2547 thermal.act= [HW,ACPI]
2548 -1: disable all active trip points in all thermal zones
2549 <degrees C>: override all lowest active trip points
2551 thermal.crt= [HW,ACPI]
2552 -1: disable all critical trip points in all thermal zones
2553 <degrees C>: override all critical trip points
2555 thermal.nocrt= [HW,ACPI]
2556 Set to disable actions on ACPI thermal zone
2557 critical and hot trip points.
2559 thermal.off= [HW,ACPI]
2560 1: disable ACPI thermal control
2562 thermal.psv= [HW,ACPI]
2563 -1: disable all passive trip points
2564 <degrees C>: override all passive trip points to this
2567 thermal.tzp= [HW,ACPI]
2568 Specify global default ACPI thermal zone polling rate
2569 <deci-seconds>: poll all this frequency
2570 0: no polling (default)
2573 Force threading of all interrupt handlers except those
2574 marked explicitely IRQF_NO_THREAD.
2578 Specify if the kernel should make use of the cpu
2579 topology information if the hardware supports this.
2580 The scheduler will make use of this information and
2581 e.g. base its process migration decisions on it.
2586 tpm_suspend_pcr=[HW,TPM]
2587 Format: integer pcr id
2588 Specify that at suspend time, the tpm driver
2589 should extend the specified pcr with zeros,
2590 as a workaround for some chips which fail to
2591 flush the last written pcr on TPM_SaveState.
2592 This will guarantee that all the other pcrs
2595 trace_buf_size=nn[KMG]
2596 [FTRACE] will set tracing buffer size.
2598 trace_event=[event-list]
2599 [FTRACE] Set and start specified trace events in order
2600 to facilitate early boot debugging.
2601 See also Documentation/trace/events.txt
2603 tsc= Disable clocksource stability checks for TSC.
2605 [x86] reliable: mark tsc clocksource as reliable, this
2606 disables clocksource verification at runtime, as well
2607 as the stability checks done at bootup. Used to enable
2608 high-resolution timer mode on older hardware, and in
2609 virtualized environment.
2610 [x86] noirqtime: Do not use TSC to do irq accounting.
2611 Used to run time disable IRQ_TIME_ACCOUNTING on any
2612 platforms where RDTSC is slow and this accounting
2615 turbografx.map[2|3]= [HW,JOY]
2616 TurboGraFX parallel port interface
2618 <port#>,<js1>,<js2>,<js3>,<js4>,<js5>,<js6>,<js7>
2619 See also Documentation/input/joystick-parport.txt
2621 udbg-immortal [PPC] When debugging early kernel crashes that
2622 happen after console_init() and before a proper
2623 console driver takes over, this boot options might
2624 help "seeing" what's going on.
2626 uhash_entries= [KNL,NET]
2627 Set number of hash buckets for UDP/UDP-Lite connections
2630 [USB] Ignore overcurrent events (default N).
2631 Some badly-designed motherboards generate lots of
2632 bogus events, for ports that aren't wired to
2633 anything. Set this parameter to avoid log spamming.
2634 Note that genuine overcurrent events won't be
2638 [X86] Cause panic on unknown NMI.
2640 usbcore.authorized_default=
2641 [USB] Default USB device authorization:
2642 (default -1 = authorized except for wireless USB,
2643 0 = not authorized, 1 = authorized)
2645 usbcore.autosuspend=
2646 [USB] The autosuspend time delay (in seconds) used
2647 for newly-detected USB devices (default 2). This
2648 is the time required before an idle device will be
2649 autosuspended. Devices for which the delay is set
2650 to a negative value won't be autosuspended at all.
2652 usbcore.usbfs_snoop=
2653 [USB] Set to log all usbfs traffic (default 0 = off).
2655 usbcore.blinkenlights=
2656 [USB] Set to cycle leds on hubs (default 0 = off).
2658 usbcore.old_scheme_first=
2659 [USB] Start with the old device initialization
2660 scheme (default 0 = off).
2662 usbcore.use_both_schemes=
2663 [USB] Try the other device initialization scheme
2664 if the first one fails (default 1 = enabled).
2666 usbcore.initial_descriptor_timeout=
2667 [USB] Specifies timeout for the initial 64-byte
2668 USB_REQ_GET_DESCRIPTOR request in milliseconds
2669 (default 5000 = 5.0 seconds).
2672 [USBHID] The interval which mice are to be polled at.
2674 usb-storage.delay_use=
2675 [UMS] The delay in seconds before a new device is
2676 scanned for Logical Units (default 5).
2679 [UMS] A list of quirks entries to supplement or
2680 override the built-in unusual_devs list. List
2681 entries are separated by commas. Each entry has
2682 the form VID:PID:Flags where VID and PID are Vendor
2683 and Product ID values (4-digit hex numbers) and
2684 Flags is a set of characters, each corresponding
2685 to a common usb-storage quirk flag as follows:
2686 a = SANE_SENSE (collect more than 18 bytes
2688 b = BAD_SENSE (don't collect more than 18
2689 bytes of sense data);
2690 c = FIX_CAPACITY (decrease the reported
2691 device capacity by one sector);
2692 d = NO_READ_DISC_INFO (don't use
2693 READ_DISC_INFO command);
2694 e = NO_READ_CAPACITY_16 (don't use
2695 READ_CAPACITY_16 command);
2696 h = CAPACITY_HEURISTICS (decrease the
2697 reported device capacity by one
2698 sector if the number is odd);
2699 i = IGNORE_DEVICE (don't bind to this
2701 l = NOT_LOCKABLE (don't try to lock and
2702 unlock ejectable media);
2703 m = MAX_SECTORS_64 (don't transfer more
2704 than 64 sectors = 32 KB at a time);
2705 n = INITIAL_READ10 (force a retry of the
2706 initial READ(10) command);
2707 o = CAPACITY_OK (accept the capacity
2708 reported by the device);
2709 r = IGNORE_RESIDUE (the device reports
2710 bogus residue values);
2711 s = SINGLE_LUN (the device has only one
2713 w = NO_WP_DETECT (don't test whether the
2714 medium is write-protected).
2715 Example: quirks=0419:aaf5:rl,0421:0433:rc
2717 user_debug= [KNL,ARM]
2719 See arch/arm/Kconfig.debug help text.
2720 1 - undefined instruction events
2722 4 - invalid data aborts
2725 Example: user_debug=31
2728 [X86] Flags controlling user PTE allocations.
2730 nohigh = do not allocate PTE pages in
2731 HIGHMEM regardless of setting
2735 vdso=2: enable compat VDSO (default with COMPAT_VDSO)
2736 vdso=1: enable VDSO (default)
2737 vdso=0: disable VDSO mapping
2740 vdso32=2: enable compat VDSO (default with COMPAT_VDSO)
2741 vdso32=1: enable 32-bit VDSO (default)
2742 vdso32=0: disable 32-bit VDSO mapping
2745 vector=percpu: enable percpu vector domain
2747 video= [FB] Frame buffer configuration
2748 See Documentation/fb/modedb.txt.
2750 vga= [BOOT,X86-32] Select a particular video mode
2751 See Documentation/x86/boot.txt and
2752 Documentation/svga.txt.
2753 Use vga=ask for menu.
2754 This is actually a boot loader parameter; the value is
2755 passed to the kernel using a special protocol.
2757 vmalloc=nn[KMG] [KNL,BOOT] Forces the vmalloc area to have an exact
2758 size of <nn>. This can be used to increase the
2759 minimum size (128MB on x86). It can also be used to
2760 decrease the size and leave more room for directly
2763 vmhalt= [KNL,S390] Perform z/VM CP command after system halt.
2766 vmpanic= [KNL,S390] Perform z/VM CP command after kernel panic.
2769 vmpoff= [KNL,S390] Perform z/VM CP command after power off.
2773 Controls the behavior of vsyscalls (i.e. calls to
2774 fixed addresses of 0xffffffffff600x00 from legacy
2775 code). Most statically-linked binaries and older
2776 versions of glibc use these calls. Because these
2777 functions are at fixed addresses, they make nice
2778 targets for exploits that can control RIP.
2780 emulate Vsyscalls turn into traps and are emulated
2783 native [default] Vsyscalls are native syscall
2785 This is a little bit faster than trapping
2786 and makes a few dynamic recompilers work
2787 better than they would in emulation mode.
2788 It also makes exploits much easier to write.
2790 none Vsyscalls don't work at all. This makes
2791 them quite hard to use for exploits but
2792 might break your system.
2794 vt.cur_default= [VT] Default cursor shape.
2795 Format: 0xCCBBAA, where AA, BB, and CC are the same as
2796 the parameters of the <Esc>[?A;B;Cc escape sequence;
2797 see VGA-softcursor.txt. Default: 2 = underline.
2799 vt.default_blu= [VT]
2800 Format: <blue0>,<blue1>,<blue2>,...,<blue15>
2801 Change the default blue palette of the console.
2802 This is a 16-member array composed of values
2805 vt.default_grn= [VT]
2806 Format: <green0>,<green1>,<green2>,...,<green15>
2807 Change the default green palette of the console.
2808 This is a 16-member array composed of values
2811 vt.default_red= [VT]
2812 Format: <red0>,<red1>,<red2>,...,<red15>
2813 Change the default red palette of the console.
2814 This is a 16-member array composed of values
2820 Set system-wide default UTF-8 mode for all tty's.
2821 Default is 1, i.e. UTF-8 mode is enabled for all
2822 newly opened terminals.
2824 vt.global_cursor_default=
2827 Set system-wide default for whether a cursor
2828 is shown on new VTs. Default is -1,
2829 i.e. cursors will be created by default unless
2830 overridden by individual drivers. 0 will hide
2831 cursors, 1 will display them.
2833 watchdog timers [HW,WDT] For information on watchdog timers,
2834 see Documentation/watchdog/watchdog-parameters.txt
2835 or other driver-specific files in the
2836 Documentation/watchdog/ directory.
2838 x2apic_phys [X86-64,APIC] Use x2apic physical mode instead of
2839 default x2apic cluster mode on platforms
2842 x86_mrst_timer= [X86-32,APBT]
2843 Choose timer option for x86 Moorestown MID platform.
2844 Two valid options are apbt timer only and lapic timer
2845 plus one apbt timer for broadcast timer.
2846 x86_mrst_timer=apbt_only | lapic_and_apbt
2848 xd= [HW,XT] Original XT pre-IDE (RLL encoded) disks.
2849 xd_geo= See header of drivers/block/xd.c.
2851 xen_emul_unplug= [HW,X86,XEN]
2852 Unplug Xen emulated devices
2853 Format: [unplug0,][unplug1]
2854 ide-disks -- unplug primary master IDE devices
2855 aux-ide-disks -- unplug non-primary-master IDE devices
2856 nics -- unplug network devices
2857 all -- unplug all emulated devices (NICs and IDE disks)
2858 unnecessary -- unplugging emulated devices is
2859 unnecessary even if the host did not respond to
2861 never -- do not unplug even if version check succeeds
2863 xirc2ps_cs= [NET,PCMCIA]
2865 <irq>,<irq_mask>,<io>,<full_duplex>,<do_sound>,<lockup_hack>[,<irq2>[,<irq3>[,<irq4>]]]
2867 ______________________________________________________________________
2871 Add more DRM drivers.
git.openpandora.org / pandora-kernel.git / blob