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
332 force_isolation - Force device isolation for all
333 devices. The IOMMU driver is not
334 allowed anymore to lift isolation
335 requirements as needed. This option
336 does not override iommu=pt
338 amijoy.map= [HW,JOY] Amiga joystick support
339 Map of devices attached to JOY0DAT and JOY1DAT
341 See also Documentation/input/joystick.txt
343 analog.map= [HW,JOY] Analog joystick and gamepad support
344 Specifies type or capabilities of an analog joystick
345 connected to one of 16 gameports
346 Format: <type1>,<type2>,..<type16>
349 Power management functions (SPARCstation-4/5 + deriv.)
351 Disable APC CPU standby support. SPARCstation-Fox does
352 not play well with APC CPU idle - disable it if you have
353 APC and your system crashes randomly.
355 apic= [APIC,X86-32] Advanced Programmable Interrupt Controller
356 Change the output verbosity whilst booting
357 Format: { quiet (default) | verbose | debug }
358 Change the amount of debugging information output
359 when initialising the APIC and IO-APIC components.
362 See Documentation/networking/ipv6.txt.
364 show_lapic= [APIC,X86] Advanced Programmable Interrupt Controller
365 Limit apic dumping. The parameter defines the maximal
366 number of local apics being dumped. Also it is possible
367 to set it to "all" by meaning -- no limit here.
368 Format: { 1 (default) | 2 | ... | all }.
369 The parameter valid if only apic=debug or
370 apic=verbose is specified.
371 Example: apic=debug show_lapic=all
373 apm= [APM] Advanced Power Management
374 See header of arch/x86/kernel/apm_32.c.
376 arcrimi= [HW,NET] ARCnet - "RIM I" (entirely mem-mapped) cards
377 Format: <io>,<irq>,<nodeID>
381 atarimouse= [HW,MOUSE] Atari Mouse
383 atkbd.extra= [HW] Enable extra LEDs and keys on IBM RapidAccess,
384 EzKey and similar keyboards
386 atkbd.reset= [HW] Reset keyboard during initialization
388 atkbd.set= [HW] Select keyboard code set
389 Format: <int> (2 = AT (default), 3 = PS/2)
391 atkbd.scroll= [HW] Enable scroll wheel on MS Office and similar
394 atkbd.softraw= [HW] Choose between synthetic and real raw mode
395 Format: <bool> (0 = real, 1 = synthetic (default))
397 atkbd.softrepeat= [HW]
398 Use software keyboard repeat
402 baycom_epp= [HW,AX25]
405 baycom_par= [HW,AX25] BayCom Parallel Port AX.25 Modem
407 See header of drivers/net/hamradio/baycom_par.c.
409 baycom_ser_fdx= [HW,AX25]
410 BayCom Serial Port AX.25 Modem (Full Duplex Mode)
411 Format: <io>,<irq>,<mode>[,<baud>]
412 See header of drivers/net/hamradio/baycom_ser_fdx.c.
414 baycom_ser_hdx= [HW,AX25]
415 BayCom Serial Port AX.25 Modem (Half Duplex Mode)
416 Format: <io>,<irq>,<mode>
417 See header of drivers/net/hamradio/baycom_ser_hdx.c.
419 boot_delay= Milliseconds to delay each printk during boot.
420 Values larger than 10 seconds (10000) are changed to
424 bootmem_debug [KNL] Enable bootmem allocator debug messages.
426 bttv.card= [HW,V4L] bttv (bt848 + bt878 based grabber cards)
427 bttv.radio= Most important insmod options are available as
429 bttv.pll= See Documentation/video4linux/bttv/Insmod-options
432 bulk_remove=off [PPC] This parameter disables the use of the pSeries
433 firmware feature for flushing multiple hpte entries
436 c101= [NET] Moxa C101 synchronous serial card
438 cachesize= [BUGS=X86-32] Override level 2 CPU cache size detection.
439 Sometimes CPU hardware bugs make them report the cache
440 size incorrectly. The kernel will attempt work arounds
441 to fix known problems, but for some CPUs it is not
442 possible to determine what the correct size should be.
443 This option provides an override for these situations.
446 [SECURITY] Disable capabilities. This would normally
447 be used only if an alternative security model is to be
448 configured. Potentially dangerous and should only be
449 used if you are entirely sure of the consequences.
451 ccw_timeout_log [S390]
452 See Documentation/s390/CommonIO for details.
454 cgroup_disable= [KNL] Disable a particular controller
455 Format: {name of the controller(s) to disable}
456 {Currently supported controllers - "memory"}
458 checkreqprot [SELINUX] Set initial checkreqprot flag value.
459 Format: { "0" | "1" }
460 See security/selinux/Kconfig help text.
461 0 -- check protection applied by kernel (includes
462 any implied execute protection).
463 1 -- check protection requested by application.
464 Default value is set via a kernel config option.
465 Value can be changed at runtime via
466 /selinux/checkreqprot.
469 See Documentation/s390/CommonIO for details.
471 clock= [BUGS=X86-32, HW] gettimeofday clocksource override.
473 Forces specified clocksource (if available) to be used
474 when calculating gettimeofday(). If specified
475 clocksource is not available, it defaults to PIT.
476 Format: { pit | tsc | cyclone | pmtmr }
478 clocksource= Override the default clocksource
480 Override the default clocksource and use the clocksource
481 with the name specified.
482 Some clocksource names to choose from, depending on
484 [all] jiffies (this is the base, fallback clocksource)
486 [ARM] imx_timer1,OSTS,netx_timer,mpu_timer2,
487 pxa_timer,timer3,32k_counter,timer0_1
489 [X86-32] pit,hpet,tsc;
490 scx200_hrt on Geode; cyclone on IBM x440
498 clearcpuid=BITNUM [X86]
499 Disable CPUID feature X for the kernel. See
500 arch/x86/include/asm/cpufeature.h for the valid bit
501 numbers. Note the Linux specific bits are not necessarily
502 stable over kernel options, but the vendor specific
504 Also note that user programs calling CPUID directly
505 or using the feature without checking anything
506 will still see it. This just prevents it from
507 being used by the kernel or shown in /proc/cpuinfo.
508 Also note the kernel might malfunction if you disable
511 cmo_free_hint= [PPC] Format: { yes | no }
512 Specify whether pages are marked as being inactive
513 when they are freed. This is used in CMO environments
514 to determine OS memory pressure for page stealing by
518 code_bytes [X86] How many bytes of object code to print
523 com20020= [HW,NET] ARCnet - COM20020 chipset
525 <io>[,<irq>[,<nodeID>[,<backplane>[,<ckp>[,<timeout>]]]]]
527 com90io= [HW,NET] ARCnet - COM90xx chipset (IO-mapped buffers)
531 ARCnet - COM90xx chipset (memory-mapped buffers)
532 Format: <io>[,<irq>[,<memstart>]]
534 condev= [HW,S390] console device
537 console= [KNL] Output console device and options.
539 tty<n> Use the virtual console device <n>.
543 Use the specified serial port. The options are of
544 the form "bbbbpnf", where "bbbb" is the baud rate,
545 "p" is parity ("n", "o", or "e"), "n" is number of
546 bits, and "f" is flow control ("r" for RTS or
547 omit it). Default is "9600n8".
549 See Documentation/serial-console.txt for more
551 Documentation/networking/netconsole.txt for an
554 uart[8250],io,<addr>[,options]
555 uart[8250],mmio,<addr>[,options]
556 Start an early, polled-mode console on the 8250/16550
557 UART at the specified I/O port or MMIO address,
558 switching to the matching ttyS device later. The
559 options are the same as for ttyS, above.
561 If the device connected to the port is not a TTY but a braille
562 device, prepend "brl," before the device type, for instance
564 For now, only VisioBraille is supported.
566 consoleblank= [KNL] The console blank (screen saver) timeout in
567 seconds. Defaults to 10*60 = 10mins. A value of 0
568 disables the blank timer.
571 [KNL] Change the default value for
572 /proc/<pid>/coredump_filter.
573 See also Documentation/filesystems/proc.txt.
575 cpuidle.off=1 [CPU_IDLE]
576 disable the cpuidle sub-system
578 cpcihp_generic= [HW,PCI] Generic port I/O CompactPCI driver
580 <first_slot>,<last_slot>,<port>,<enum_bit>[,<debug>]
582 crashkernel=size[KMG][@offset[KMG]]
583 [KNL] Using kexec, Linux can switch to a 'crash kernel'
584 upon panic. This parameter reserves the physical
585 memory region [offset, offset + size] for that kernel
586 image. If '@offset' is omitted, then a suitable offset
587 is selected automatically. Check
588 Documentation/kdump/kdump.txt for further details.
590 crashkernel=range1:size1[,range2:size2,...][@offset]
591 [KNL] Same as above, but depends on the memory
592 in the running system. The syntax of range is
593 start-[end] where start and end are both
594 a memory unit (amount[KMG]). See also
595 Documentation/kdump/kdump.txt for an example.
600 cs89x0_media= [HW,NET]
601 Format: { rj45 | aui | bnc }
604 See header of drivers/s390/block/dasd_devmap.c.
606 db9.dev[2|3]= [HW,JOY] Multisystem joystick support via parallel port
607 (one device per port)
608 Format: <port#>,<type>
609 See also Documentation/input/joystick-parport.txt
611 ddebug_query= [KNL,DYNAMIC_DEBUG] Enable debug messages at early boot
612 time. See Documentation/dynamic-debug-howto.txt for
615 debug [KNL] Enable kernel debugging (events log level).
618 [KNL] verbose self-tests
620 Print debugging info while doing the locking API
622 We default to 0 (no extra messages), setting it to
623 1 will print _a lot_ more information - normally
624 only useful to kernel developers.
626 debug_objects [KNL] Enable object debugging
629 [KNL] Disable object debugging
631 debugpat [X86] Enable PAT debugging
633 decnet.addr= [HW,NET]
634 Format: <area>[,<node>]
635 See also Documentation/networking/decnet.txt.
638 [same as hugepagesz=] The size of the default
639 HugeTLB page size. This is the size represented by
640 the legacy /proc/ hugepages APIs, used for SHM, and
641 default size when mounting hugetlbfs filesystems.
642 Defaults to the default architecture's huge page size
646 Set number of hash buckets for dentry cache.
649 IO parameters + enable/disable command.
651 digiepca= [HW,SERIAL]
652 See drivers/char/README.epca and
653 Documentation/serial/digiepca.txt.
656 See Documentation/networking/ipv6.txt.
658 disable_ddw [PPC/PSERIES]
659 Disable Dynamic DMA Window support. Use this if
660 to workaround buggy firmware.
663 See Documentation/networking/ipv6.txt.
665 disable_mtrr_cleanup [X86]
666 The kernel tries to adjust MTRR layout from continuous
667 to discrete, to make X server driver able to add WB
668 entry later. This parameter disables that.
670 disable_mtrr_trim [X86, Intel and AMD only]
671 By default the kernel will trim any uncacheable
672 memory out of your available memory pool based on
673 MTRR settings. This parameter disables that behavior,
674 possibly causing your machine to run very slowly.
676 disable_timer_pin_1 [X86]
677 Disable PIN 1 of APIC timer
678 Can be useful to work around chipset bugs.
680 dma_debug=off If the kernel is compiled with DMA_API_DEBUG support,
681 this option disables the debugging code at boot.
683 dma_debug_entries=<number>
684 This option allows to tune the number of preallocated
685 entries for DMA-API debugging code. One entry is
686 required per DMA-API allocation. Use this if the
687 DMA-API debugging code disables itself because the
688 architectural default is too low.
690 dma_debug_driver=<driver_name>
691 With this option the DMA-API debugging driver
692 filter feature can be enabled at boot time. Just
693 pass the driver to filter for as the parameter.
694 The filter can be disabled or changed to another
695 driver later using sysfs.
699 earlycon= [KNL] Output early console device and options.
700 uart[8250],io,<addr>[,options]
701 uart[8250],mmio,<addr>[,options]
702 uart[8250],mmio32,<addr>[,options]
703 Start an early, polled-mode console on the 8250/16550
704 UART at the specified I/O port or MMIO address.
705 MMIO inter-register address stride is either 8-bit
706 (mmio) or 32-bit (mmio32).
707 The options are the same as for ttyS, above.
709 earlyprintk= [X86,SH,BLACKFIN]
711 earlyprintk=serial[,ttySn[,baudrate]]
712 earlyprintk=ttySn[,baudrate]
713 earlyprintk=dbgp[debugController#]
715 Append ",keep" to not disable it when the real console
718 Only vga or serial or usb debug port at a time.
720 Currently only ttyS0 and ttyS1 are supported.
722 Interaction with the standard serial driver is not
725 The VGA output is eventually overwritten by the real
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 eisa_irq_edge= [PARISC,HW]
738 See header of drivers/parisc/eisa.c.
741 See comment before function elanfreq_setup() in
742 arch/x86/kernel/cpu/cpufreq/elanfreq.c.
745 Format: {"cfq" | "deadline" | "noop"}
746 See Documentation/block/cfq-iosched.txt and
747 Documentation/block/deadline-iosched.txt for details.
749 elfcorehdr=[size[KMG]@]offset[KMG] [IA64,PPC,SH,X86,S390]
750 Specifies physical address of start of kernel core
751 image elf header and optionally the size. Generally
752 kexec loader will pass this option to capture kernel.
753 See Documentation/kdump/kdump.txt for details.
755 enable_mtrr_cleanup [X86]
756 The kernel tries to adjust MTRR layout from continuous
757 to discrete, to make X server driver able to add WB
758 entry later. This parameter enables that.
760 enable_timer_pin_1 [X86]
761 Enable PIN 1 of APIC timer
762 Can be useful to work around chipset bugs
763 (in particular on some ATI chipsets).
764 The kernel tries to set a reasonable default.
766 enforcing [SELINUX] Set initial enforcing status.
768 See security/selinux/Kconfig help text.
769 0 -- permissive (log only, no denials).
770 1 -- enforcing (deny and log).
772 Value can be changed at runtime via /selinux/enforce.
775 Disable Error Record Serialization Table (ERST)
778 ether= [HW,NET] Ethernet cards parameters
779 This option is obsoleted by the "netdev=" option, which
780 has equivalent usage. See its documentation for details.
784 Permit 'security.evm' to be updated regardless of
785 current integrity status.
789 fail_make_request=[KNL]
790 General fault injection mechanism.
791 Format: <interval>,<probability>,<space>,<times>
792 See also Documentation/fault-injection/.
795 See Documentation/blockdev/floppy.txt.
797 force_pal_cache_flush
798 [IA-64] Avoid check_sal_cache_flush which may hang on
799 buggy SAL_CACHE_FLUSH implementations. Using this
800 parameter will force ia64_sal_cache_flush to call
801 ia64_pal_cache_flush instead of SAL_CACHE_FLUSH.
804 [FTRACE] will set and start the specified tracer
805 as early as possible in order to facilitate early
808 ftrace_dump_on_oops[=orig_cpu]
809 [FTRACE] will dump the trace buffers on oops.
810 If no parameter is passed, ftrace will dump
811 buffers of all CPUs, but if you pass orig_cpu, it will
812 dump only the buffer of the CPU that triggered the
815 ftrace_filter=[function-list]
816 [FTRACE] Limit the functions traced by the function
817 tracer at boot up. function-list is a comma separated
818 list of functions. This list can be changed at run
819 time by the set_ftrace_filter file in the debugfs
822 ftrace_notrace=[function-list]
823 [FTRACE] Do not trace the functions specified in
824 function-list. This list can be changed at run time
825 by the set_ftrace_notrace file in the debugfs
828 ftrace_graph_filter=[function-list]
829 [FTRACE] Limit the top level callers functions traced
830 by the function graph tracer at boot up.
831 function-list is a comma separated list of functions
832 that can be changed at run time by the
833 set_graph_function file in the debugfs tracing directory.
836 [HW,JOY] Multisystem joystick and NES/SNES/PSX pad
837 support via parallel port (up to 5 devices per port)
838 Format: <port#>,<pad1>,<pad2>,<pad3>,<pad4>,<pad5>
839 See also Documentation/input/joystick-parport.txt
843 gart_fix_e820= [X86_64] disable the fix e820 for K8 GART
847 gcov_persist= [GCOV] When non-zero (default), profiling data for
848 kernel modules is saved and remains accessible via
849 debugfs, even when the module is unloaded/reloaded.
850 When zero, profiling data is discarded and associated
851 debugfs files are removed at module unload time.
853 gpt [EFI] Forces disk with valid GPT signature but
854 invalid Protective MBR to be treated as GPT.
856 hashdist= [KNL,NUMA] Large hashes allocated during boot
857 are distributed across NUMA nodes. Defaults on
858 for 64-bit NUMA, off otherwise.
859 Format: 0 | 1 (for off | on)
861 hcl= [IA-64] SGI's Hardware Graph compatibility layer
863 hd= [EIDE] (E)IDE hard drive subsystem geometry
864 Format: <cyl>,<head>,<sect>
867 Disable Hardware Error Source Table (HEST) support;
868 corresponding firmware-first mode error processing
869 logic will be disabled.
871 highmem=nn[KMG] [KNL,BOOT] forces the highmem zone to have an exact
872 size of <nn>. This works even on boxes that have no
873 highmem otherwise. This also works to reduce highmem
874 size on bigger boxes.
876 highres= [KNL] Enable/disable high resolution timer mode.
877 Valid parameters: "on", "off"
881 See Documentation/isdn/README.HiSax.
885 hpet= [X86-32,HPET] option to control HPET usage
886 Format: { enable (default) | disable | force |
888 disable: disable HPET and use PIT instead
889 force: allow force enabled of undocumented chips (ICH4,
891 verbose: show contents of HPET registers during setup
893 hugepages= [HW,X86-32,IA-64] HugeTLB pages to allocate at boot.
894 hugepagesz= [HW,IA-64,PPC,X86-64] The size of the HugeTLB pages.
895 On x86-64 and powerpc, this option can be specified
896 multiple times interleaved with hugepages= to reserve
897 huge pages of different sizes. Valid pages sizes on
898 x86-64 are 2M (when the CPU supports "pse") and 1G
899 (when the CPU supports the "pdpe1gb" cpuinfo flag)
900 Note that 1GB pages can only be allocated at boot time
901 using hugepages= and not freed afterwards.
903 hvc_iucv= [S390] Number of z/VM IUCV hypervisor console (HVC)
904 terminal devices. Valid values: 0..8
905 hvc_iucv_allow= [S390] Comma-separated list of z/VM user IDs.
906 If specified, z/VM IUCV HVC accepts connections
907 from listed z/VM user IDs only.
910 Do not unregister boot console at start. This is only
911 useful for debugging when something happens in the window
912 between unregistering the boot console and initializing
915 i2c_bus= [HW] Override the default board specific I2C bus speed
916 or register an additional I2C bus that is not
917 registered from board initialization code.
921 i8042.debug [HW] Toggle i8042 debug mode
922 i8042.direct [HW] Put keyboard port into non-translated mode
923 i8042.dumbkbd [HW] Pretend that controller can only read data from
924 keyboard and cannot control its state
925 (Don't attempt to blink the leds)
926 i8042.noaux [HW] Don't check for auxiliary (== mouse) port
927 i8042.nokbd [HW] Don't check/create keyboard port
928 i8042.noloop [HW] Disable the AUX Loopback command while probing
930 i8042.nomux [HW] Don't check presence of an active multiplexing
932 i8042.nopnp [HW] Don't use ACPIPnP / PnPBIOS to discover KBD/AUX
934 i8042.notimeout [HW] Ignore timeout condition signalled by conroller
935 i8042.reset [HW] Reset the controller during init and cleanup
936 i8042.unlock [HW] Unlock (ignore) the keylock
940 i8k.ignore_dmi [HW] Continue probing hardware even if DMI data
941 indicates that the driver is running on unsupported
943 i8k.force [HW] Activate i8k driver even if SMM BIOS signature
944 does not match list of supported models.
946 [HW] Report power status in /proc/i8k
947 (disabled by default)
948 i8k.restricted [HW] Allow controlling fans only if SYS_ADMIN
952 Format: <io>[,<membase>[,<icn_id>[,<icn_id2>]]]
954 ide-core.nodma= [HW] (E)IDE subsystem
955 Format: =0.0 to prevent dma on hda, =0.1 hdb =1.0 hdc
956 .vlb_clock .pci_clock .noflush .nohpa .noprobe .nowerr
957 .cdrom .chs .ignore_cable are additional options
958 See Documentation/ide/ide.txt.
960 ide-pci-generic.all-generic-ide [HW] (E)IDE subsystem
961 Claim all unknown PCI IDE storage controllers.
964 Format: idle=poll, idle=mwait, idle=halt, idle=nomwait
965 Poll forces a polling idle loop that can slightly
966 improve the performance of waking up a idle CPU, but
967 will use a lot of power and make the system run hot.
969 idle=mwait: On systems which support MONITOR/MWAIT but
970 the kernel chose to not use it because it doesn't save
971 as much power as a normal idle loop, use the
972 MONITOR/MWAIT idle loop anyways. Performance should be
973 the same as idle=poll.
974 idle=halt: Halt is forced to be used for CPU idle.
975 In such case C2/C3 won't be used again.
976 idle=nomwait: Disable mwait for CPU C-states
978 ignore_loglevel [KNL]
979 Ignore loglevel setting - this will print /all/
980 kernel messages to the console. Useful for debugging.
981 We also add it as printk module parameter, so users
982 could change it dynamically, usually by
983 /sys/module/printk/parameters/ignore_loglevel.
986 Set number of hash buckets for inode cache.
989 Format: { "0" | "1" }
990 0 -- integrity auditing messages. (Default)
991 1 -- enable informational integrity auditing messages.
994 Format: { "sha1" | "md5" }
998 Load a policy which meets the needs of the Trusted
999 Computing Base. This means IMA will measure all
1000 programs exec'd, files mmap'd for exec, and all files
1001 opened for read by uid=0.
1005 Run specified binary instead of /sbin/init as init
1008 initcall_debug [KNL] Trace initcalls as they are executed. Useful
1009 for working out where the kernel is dying during
1012 initrd= [BOOT] Specify the location of the initial ramdisk
1014 inport.irq= [HW] Inport (ATI XL and Microsoft) busmouse driver
1017 intel_iommu= [DMAR] Intel IOMMU driver (DMAR) option
1019 Enable intel iommu driver.
1021 Disable intel iommu driver.
1022 igfx_off [Default Off]
1023 By default, gfx is mapped as normal device. If a gfx
1024 device has a dedicated DMAR unit, the DMAR unit is
1025 bypassed by not enabling DMAR with this option. In
1026 this case, gfx device will use physical address for
1029 With this option iommu will not optimize to look
1030 for io virtual address below 32-bit forcing dual
1031 address cycle on pci bus for cards supporting greater
1032 than 32-bit addressing. The default is to look
1033 for translation below 32-bit and if not available
1034 then look in the higher range.
1035 strict [Default Off]
1036 With this option on every unmap_single operation will
1037 result in a hardware IOTLB flush operation as opposed
1038 to batching them for performance.
1039 sp_off [Default Off]
1040 By default, super page will be supported if Intel IOMMU
1041 has the capability. With this option, super page will
1043 intremap= [X86-64, Intel-IOMMU]
1044 on enable Interrupt Remapping (default)
1045 off disable Interrupt Remapping
1046 nosid disable Source ID checking
1048 BIOS x2APIC opt-out request will be ignored
1052 iomem= Disable strict checking of access to MMIO memory
1053 strict regions from userspace.
1068 group_mf [x86, IA-64]
1071 io7= [HW] IO7 for Marvel based alpha systems
1072 See comment before marvel_specify_io7 in
1073 arch/alpha/kernel/core_marvel.c.
1075 io_delay= [X86] I/O delay method
1077 Standard port 0x80 based delay
1079 Alternate port 0xed based delay (needed on some systems)
1081 Simple two microseconds delay
1086 See Documentation/filesystems/nfs/nfsroot.txt.
1088 ip2= [HW] Set IO/IRQ pairs for up to 4 IntelliPort boards
1089 See comment before ip2_setup() in
1090 drivers/char/ip2/ip2base.c.
1093 When an interrupt is not handled search all handlers
1094 for it. Intended to get systems with badly broken
1098 When an interrupt is not handled search all handlers
1099 for it. Also check all handlers each timer
1100 interrupt. Intended to get systems with badly broken
1104 Format: <RDP>,<reset>,<pci_scan>,<verbosity>
1106 isolcpus= [KNL,SMP] Isolate CPUs from the general scheduler.
1108 <cpu number>,...,<cpu number>
1110 <cpu number>-<cpu number>
1111 (must be a positive range in ascending order)
1113 <cpu number>,...,<cpu number>-<cpu number>
1115 This option can be used to specify one or more CPUs
1116 to isolate from the general SMP balancing and scheduling
1117 algorithms. You can move a process onto or off an
1118 "isolated" CPU via the CPU affinity syscalls or cpuset.
1119 <cpu number> begins at 0 and the maximum value is
1120 "number of CPUs in system - 1".
1122 This option is the preferred way to isolate CPUs. The
1123 alternative -- manually setting the CPU mask of all
1124 tasks in the system -- can cause problems and
1125 suboptimal load balancer performance.
1129 js= [HW,JOY] Analog joystick
1130 See Documentation/input/joystick.txt.
1134 kernelcore=nn[KMG] [KNL,X86,IA-64,PPC] This parameter
1135 specifies the amount of memory usable by the kernel
1136 for non-movable allocations. The requested amount is
1137 spread evenly throughout all nodes in the system. The
1138 remaining memory in each node is used for Movable
1139 pages. In the event, a node is too small to have both
1140 kernelcore and Movable pages, kernelcore pages will
1141 take priority and other nodes will have a larger number
1142 of kernelcore pages. The Movable zone is used for the
1143 allocation of pages that may be reclaimed or moved
1144 by the page migration subsystem. This means that
1145 HugeTLB pages may not be allocated from this zone.
1146 Note that allocations like PTEs-from-HighMem still
1147 use the HighMem zone if it exists, and the Normal
1148 zone if it does not.
1150 kgdbdbgp= [KGDB,HW] kgdb over EHCI usb debug port.
1151 Format: <Controller#>[,poll interval]
1152 The controller # is the number of the ehci usb debug
1153 port as it is probed via PCI. The poll interval is
1154 optional and is the number seconds in between
1155 each poll cycle to the debug port in case you need
1156 the functionality for interrupting the kernel with
1157 gdb or control-c on the dbgp connection. When
1158 not using this parameter you use sysrq-g to break into
1159 the kernel debugger.
1161 kgdboc= [KGDB,HW] kgdb over consoles.
1162 Requires a tty driver that supports console polling,
1163 or a supported polling keyboard driver (non-usb).
1164 Serial only format: <serial_device>[,baud]
1165 keyboard only format: kbd
1166 keyboard and serial format: kbd,<serial_device>[,baud]
1167 Optional Kernel mode setting:
1168 kms, kbd format: kms,kbd
1169 kms, kbd and serial format: kms,kbd,<ser_dev>[,baud]
1171 kgdbwait [KGDB] Stop kernel execution and enter the
1172 kernel debugger at the earliest opportunity.
1174 kmac= [MIPS] korina ethernet MAC address.
1175 Configure the RouterBoard 532 series on-chip
1176 Ethernet adapter MAC address.
1178 kmemleak= [KNL] Boot-time kmemleak enable/disable
1179 Valid arguments: on, off
1182 kstack=N [X86] Print N words from the kernel stack
1185 kvm.ignore_msrs=[KVM] Ignore guest accesses to unhandled MSRs.
1186 Default is 0 (don't ignore, but inject #GP)
1188 kvm.mmu_audit= [KVM] This is a R/W parameter which allows audit
1192 kvm-amd.nested= [KVM,AMD] Allow nested virtualization in KVM/SVM.
1193 Default is 1 (enabled)
1195 kvm-amd.npt= [KVM,AMD] Disable nested paging (virtualized MMU)
1197 Default is 1 (enabled) if in 64-bit or 32-bit PAE mode.
1199 kvm-intel.ept= [KVM,Intel] Disable extended page tables
1200 (virtualized MMU) support on capable Intel chips.
1201 Default is 1 (enabled)
1203 kvm-intel.emulate_invalid_guest_state=
1204 [KVM,Intel] Enable emulation of invalid guest states
1205 Default is 0 (disabled)
1207 kvm-intel.flexpriority=
1208 [KVM,Intel] Disable FlexPriority feature (TPR shadow).
1209 Default is 1 (enabled)
1212 [KVM,Intel] Enable VMX nesting (nVMX).
1213 Default is 0 (disabled)
1215 kvm-intel.unrestricted_guest=
1216 [KVM,Intel] Disable unrestricted guest feature
1217 (virtualized real and unpaged mode) on capable
1218 Intel chips. Default is 1 (enabled)
1220 kvm-intel.vpid= [KVM,Intel] Disable Virtual Processor Identification
1221 feature (tagged TLBs) on capable Intel chips.
1222 Default is 1 (enabled)
1228 lapic [X86-32,APIC] Enable the local APIC even if BIOS
1231 lapic_timer_c2_ok [X86,APIC] trust the local apic timer
1234 libata.dma= [LIBATA] DMA control
1235 libata.dma=0 Disable all PATA and SATA DMA
1236 libata.dma=1 PATA and SATA Disk DMA only
1237 libata.dma=2 ATAPI (CDROM) DMA only
1238 libata.dma=4 Compact Flash DMA only
1239 Combinations also work, so libata.dma=3 enables DMA
1240 for disks and CDROMs, but not CFs.
1242 libata.ignore_hpa= [LIBATA] Ignore HPA limit
1243 libata.ignore_hpa=0 keep BIOS limits (default)
1244 libata.ignore_hpa=1 ignore limits, using full disk
1246 libata.noacpi [LIBATA] Disables use of ACPI in libata suspend/resume
1250 libata.force= [LIBATA] Force configurations. The format is comma
1251 separated list of "[ID:]VAL" where ID is
1252 PORT[.DEVICE]. PORT and DEVICE are decimal numbers
1253 matching port, link or device. Basically, it matches
1254 the ATA ID string printed on console by libata. If
1255 the whole ID part is omitted, the last PORT and DEVICE
1256 values are used. If ID hasn't been specified yet, the
1257 configuration applies to all ports, links and devices.
1259 If only DEVICE is omitted, the parameter applies to
1260 the port and all links and devices behind it. DEVICE
1261 number of 0 either selects the first device or the
1262 first fan-out link behind PMP device. It does not
1263 select the host link. DEVICE number of 15 selects the
1264 host link and device attached to it.
1266 The VAL specifies the configuration to force. As long
1267 as there's no ambiguity shortcut notation is allowed.
1268 For example, both 1.5 and 1.5G would work for 1.5Gbps.
1269 The following configurations can be forced.
1271 * Cable type: 40c, 80c, short40c, unk, ign or sata.
1272 Any ID with matching PORT is used.
1274 * SATA link speed limit: 1.5Gbps or 3.0Gbps.
1276 * Transfer mode: pio[0-7], mwdma[0-4] and udma[0-7].
1277 udma[/][16,25,33,44,66,100,133] notation is also
1280 * [no]ncq: Turn on or off NCQ.
1282 * nohrst, nosrst, norst: suppress hard, soft
1285 * dump_id: dump IDENTIFY data.
1287 If there are multiple matching configurations changing
1288 the same attribute, the last one is used.
1290 memblock=debug [KNL] Enable memblock debug messages.
1292 load_ramdisk= [RAM] List of ramdisks to load from floppy
1293 See Documentation/blockdev/ramdisk.txt.
1295 lockd.nlm_grace_period=P [NFS] Assign grace period.
1298 lockd.nlm_tcpport=N [NFS] Assign TCP port.
1301 lockd.nlm_timeout=T [NFS] Assign timeout value.
1304 lockd.nlm_udpport=M [NFS] Assign UDP port.
1307 logibm.irq= [HW,MOUSE] Logitech Bus Mouse Driver
1310 loglevel= All Kernel Messages with a loglevel smaller than the
1311 console loglevel will be printed to the console. It can
1312 also be changed with klogd or other programs. The
1313 loglevels are defined as follows:
1315 0 (KERN_EMERG) system is unusable
1316 1 (KERN_ALERT) action must be taken immediately
1317 2 (KERN_CRIT) critical conditions
1318 3 (KERN_ERR) error conditions
1319 4 (KERN_WARNING) warning conditions
1320 5 (KERN_NOTICE) normal but significant condition
1321 6 (KERN_INFO) informational
1322 7 (KERN_DEBUG) debug-level messages
1324 log_buf_len=n[KMG] Sets the size of the printk ring buffer,
1325 in bytes. n must be a power of two. The default
1326 size is set in the kernel config file.
1328 logo.nologo [FB] Disables display of the built-in Linux logo.
1329 This may be used to provide more screen space for
1330 kernel log messages and is useful when debugging
1331 kernel boot problems.
1333 lp=0 [LP] Specify parallel ports to use, e.g,
1334 lp=port[,port...] lp=none,parport0 (lp0 not configured, lp1 uses
1335 lp=reset first parallel port). 'lp=0' disables the
1336 lp=auto printer driver. 'lp=reset' (which can be
1337 specified in addition to the ports) causes
1338 attached printers to be reset. Using
1339 lp=port1,port2,... specifies the parallel ports
1340 to associate lp devices with, starting with
1341 lp0. A port specification may be 'none' to skip
1342 that lp device, or a parport name such as
1343 'parport0'. Specifying 'lp=auto' instead of a
1344 port specification list means that device IDs
1345 from each port should be examined, to see if
1346 an IEEE 1284-compliant printer is attached; if
1347 so, the driver will manage that printer.
1348 See also header of drivers/char/lp.c.
1351 Sets loops_per_jiffy to given constant, thus avoiding
1352 time-consuming boot-time autodetection (up to 250 ms per
1353 CPU). 0 enables autodetection (default). To determine
1354 the correct value for your kernel, boot with normal
1355 autodetection and see what value is printed. Note that
1356 on SMP systems the preset will be applied to all CPUs,
1357 which is likely to cause problems if your CPUs need
1358 significantly divergent settings. An incorrect value
1359 will cause delays in the kernel to be wrong, leading to
1360 unpredictable I/O errors and other breakage. Although
1361 unlikely, in the extreme case this might damage your
1365 Format: <io>,<irq>,<dma>
1367 machvec= [IA-64] Force the use of a particular machine-vector
1368 (machvec) in a generic kernel.
1369 Example: machvec=hpzx1_swiotlb
1371 machtype= [Loongson] Share the same kernel image file between different
1373 Example: machtype=lemote-yeeloong-2f-7inch
1375 max_addr=nn[KMG] [KNL,BOOT,ia64] All physical memory greater
1376 than or equal to this physical address is ignored.
1378 maxcpus= [SMP] Maximum number of processors that an SMP kernel
1379 should make use of. maxcpus=n : n >= 0 limits the
1380 kernel to using 'n' processors. n=0 is a special case,
1381 it is equivalent to "nosmp", which also disables
1384 max_loop= [LOOP] The number of loop block devices that get
1385 (loop.max_loop) unconditionally pre-created at init time. The default
1386 number is configured by BLK_DEV_LOOP_MIN_COUNT. Instead
1387 of statically allocating a predefined number, loop
1388 devices can be requested on-demand with the
1389 /dev/loop-control interface.
1393 mce [X86-32] Machine Check Exception
1395 mce=option [X86-64] See Documentation/x86/x86_64/boot-options.txt
1397 md= [HW] RAID subsystems devices and level
1398 See Documentation/md.txt.
1401 Format: <first>,<last>
1402 Specifies range of consoles to be captured by the MDA.
1404 mem=nn[KMG] [KNL,BOOT] Force usage of a specific amount of memory
1405 Amount of memory to be used when the kernel is not able
1406 to see the whole system memory or for test.
1407 [X86-32] Use together with memmap= to avoid physical
1408 address space collisions. Without memmap= PCI devices
1409 could be placed at addresses belonging to unused RAM.
1411 mem=nopentium [BUGS=X86-32] Disable usage of 4MB pages for kernel
1415 [KNL,SH] Allow user to override the default size for
1416 per-device physically contiguous DMA buffers.
1418 memmap=exactmap [KNL,X86] Enable setting of an exact
1419 E820 memory map, as specified by the user.
1420 Such memmap=exactmap lines can be constructed based on
1421 BIOS output or other requirements. See the memmap=nn@ss
1424 memmap=nn[KMG]@ss[KMG]
1425 [KNL] Force usage of a specific region of memory
1426 Region of memory to be used, from ss to ss+nn.
1428 memmap=nn[KMG]#ss[KMG]
1429 [KNL,ACPI] Mark specific memory as ACPI data.
1430 Region of memory to be used, from ss to ss+nn.
1432 memmap=nn[KMG]$ss[KMG]
1433 [KNL,ACPI] Mark specific memory as reserved.
1434 Region of memory to be used, from ss to ss+nn.
1435 Example: Exclude memory from 0x18690000-0x1869ffff
1436 memmap=64K$0x18690000
1438 memmap=0x10000$0x18690000
1440 memory_corruption_check=0/1 [X86]
1441 Some BIOSes seem to corrupt the first 64k of
1442 memory when doing things like suspend/resume.
1443 Setting this option will scan the memory
1444 looking for corruption. Enabling this will
1445 both detect corruption and prevent the kernel
1446 from using the memory being corrupted.
1447 However, its intended as a diagnostic tool; if
1448 repeatable BIOS-originated corruption always
1449 affects the same memory, you can use memmap=
1450 to prevent the kernel from using that memory.
1452 memory_corruption_check_size=size [X86]
1453 By default it checks for corruption in the low
1454 64k, making this memory unavailable for normal
1455 use. Use this parameter to scan for
1456 corruption in more or less memory.
1458 memory_corruption_check_period=seconds [X86]
1459 By default it checks for corruption every 60
1460 seconds. Use this parameter to check at some
1461 other rate. 0 disables periodic checking.
1463 memtest= [KNL,X86] Enable memtest
1465 default : 0 <disable>
1466 Specifies the number of memtest passes to be
1467 performed. Each pass selects another test
1468 pattern from a given set of patterns. Memtest
1469 fills the memory with this pattern, validates
1470 memory contents and reserves bad memory
1471 regions that are detected.
1473 meye.*= [HW] Set MotionEye Camera parameters
1474 See Documentation/video4linux/meye.txt.
1476 mfgpt_irq= [IA-32] Specify the IRQ to use for the
1477 Multi-Function General Purpose Timers on AMD Geode
1480 mfgptfix [X86-32] Fix MFGPT timers on AMD Geode platforms when
1481 the BIOS has incorrectly applied a workaround. TinyBIOS
1482 version 0.98 is known to be affected, 0.99 fixes the
1483 problem by letting the user disable the workaround.
1487 min_addr=nn[KMG] [KNL,BOOT,ia64] All physical memory below this
1488 physical address is ignored.
1490 mini2440= [ARM,HW,KNL]
1491 Format:[0..2][b][c][t]
1493 MINI2440 configuration specification:
1494 0 - The attached screen is the 3.5" TFT
1495 1 - The attached screen is the 7" TFT
1496 2 - The VGA Shield is attached (1024x768)
1497 Leaving out the screen size parameter will not load
1498 the TFT driver, and the framebuffer will be left
1500 b - Enable backlight. The TFT backlight pin will be
1501 linked to the kernel VESA blanking code and a GPIO
1502 LED. This parameter is not necessary when using the
1504 c - Enable the s3c camera interface.
1505 t - Reserved for enabling touchscreen support. The
1506 touchscreen support is not enabled in the mainstream
1507 kernel as of 2.6.30, a preliminary port can be found
1508 in the "bleeding edge" mini2440 support kernel at
1509 http://repo.or.cz/w/linux-2.6/mini2440.git
1512 [KNL] When CONFIG_DEBUG_MEMORY_INIT is set, this
1513 parameter allows control of the logging verbosity for
1514 the additional memory initialisation checks. A value
1515 of 0 disables mminit logging and a level of 4 will
1516 log everything. Information is printed at KERN_DEBUG
1517 so loglevel=8 may also need to be specified.
1520 [MOUSE] Maximum time between finger touching and
1521 leaving touchpad surface for touch to be considered
1522 a tap and be reported as a left button click (for
1523 touchpads working in absolute mode only).
1525 mousedev.xres= [MOUSE] Horizontal screen resolution, used for devices
1526 reporting absolute coordinates, such as tablets
1527 mousedev.yres= [MOUSE] Vertical screen resolution, used for devices
1528 reporting absolute coordinates, such as tablets
1530 movablecore=nn[KMG] [KNL,X86,IA-64,PPC] This parameter
1531 is similar to kernelcore except it specifies the
1532 amount of memory used for migratable allocations.
1533 If both kernelcore and movablecore is specified,
1534 then kernelcore will be at *least* the specified
1535 value but may be more. If movablecore on its own
1536 is specified, the administrator must be careful
1537 that the amount of memory usable for all allocations
1540 MTD_Partition= [MTD]
1541 Format: <name>,<region-number>,<size>,<offset>
1543 MTD_Region= [MTD] Format:
1544 <name>,<region-number>[,<base>,<size>,<buswidth>,<altbuswidth>]
1547 See drivers/mtd/cmdlinepart.c.
1549 multitce=off [PPC] This parameter disables the use of the pSeries
1550 firmware feature for updating multiple TCE entries
1553 onenand.bdry= [HW,MTD] Flex-OneNAND Boundary Configuration
1555 Format: [die0_boundary][,die0_lock][,die1_boundary][,die1_lock]
1557 boundary - index of last SLC block on Flex-OneNAND.
1558 The remaining blocks are configured as MLC blocks.
1559 lock - Configure if Flex-OneNAND boundary should be locked.
1560 Once locked, the boundary cannot be changed.
1561 1 indicates lock status, 0 indicates unlock status.
1564 ARM/S3C2412 JIVE boot control
1566 See arch/arm/mach-s3c2412/mach-jive.c
1568 mtouchusb.raw_coordinates=
1569 [HW] Make the MicroTouch USB driver use raw coordinates
1570 ('y', default) or cooked coordinates ('n')
1572 mtrr_chunk_size=nn[KMG] [X86]
1573 used for mtrr cleanup. It is largest continuous chunk
1574 that could hold holes aka. UC entries.
1576 mtrr_gran_size=nn[KMG] [X86]
1577 Used for mtrr cleanup. It is granularity of mtrr block.
1579 Large value could prevent small alignment from
1582 mtrr_spare_reg_nr=n [X86]
1584 Range: 0,7 : spare reg number
1586 Used for mtrr cleanup. It is spare mtrr entries number.
1587 Set to 2 or more if your graphical card needs more.
1589 n2= [NET] SDL Inc. RISCom/N2 synchronous serial card
1591 netdev= [NET] Network devices parameters
1592 Format: <irq>,<io>,<mem_start>,<mem_end>,<name>
1593 Note that mem_start is often overloaded to mean
1594 something different and driver-specific.
1595 This usage is only documented in each driver source
1599 [NETFILTER] Enable connection tracking flow accounting
1600 0 to disable accounting
1601 1 to enable accounting
1604 nfsaddrs= [NFS] Deprecated. Use ip= instead.
1605 See Documentation/filesystems/nfs/nfsroot.txt.
1607 nfsroot= [NFS] nfs root filesystem for disk-less boxes.
1608 See Documentation/filesystems/nfs/nfsroot.txt.
1610 nfsrootdebug [NFS] enable nfsroot debugging messages.
1611 See Documentation/filesystems/nfs/nfsroot.txt.
1613 nfs.callback_tcpport=
1614 [NFS] set the TCP port on which the NFSv4 callback
1615 channel should listen.
1618 [NFS] sets the pathname to the program which is used
1619 to update the NFS client cache entries.
1621 nfs.cache_getent_timeout=
1622 [NFS] sets the timeout after which an attempt to
1623 update a cache entry is deemed to have failed.
1625 nfs.idmap_cache_timeout=
1626 [NFS] set the maximum lifetime for idmapper cache
1630 [NFS] enable 64-bit inode numbers.
1631 If zero, the NFS client will fake up a 32-bit inode
1632 number for the readdir() and stat() syscalls instead
1633 of returning the full 64-bit number.
1634 The default is to return 64-bit inode numbers.
1636 nfs.nfs4_disable_idmapping=
1637 [NFSv4] When set to the default of '1', this option
1638 ensures that both the RPC level authentication
1639 scheme and the NFS level operations agree to use
1640 numeric uids/gids if the mount is using the
1641 'sec=sys' security flavour. In effect it is
1642 disabling idmapping, which can make migration from
1643 legacy NFSv2/v3 systems to NFSv4 easier.
1644 Servers that do not support this mode of operation
1645 will be autodetected by the client, and it will fall
1646 back to using the idmapper.
1647 To turn off this behaviour, set the value to '0'.
1649 nmi_debug= [KNL,AVR32,SH] Specify one or more actions to take
1650 when a NMI is triggered.
1651 Format: [state][,regs][,debounce][,die]
1653 nmi_watchdog= [KNL,BUGS=X86] Debugging features for SMP kernels
1654 Format: [panic,][nopanic,][num]
1656 0 - turn nmi_watchdog off
1657 When panic is specified, panic when an NMI watchdog
1658 timeout occurs (or 'nopanic' to override the opposite
1660 This is useful when you use a panic=... timeout and
1661 need the box quickly up again.
1663 netpoll.carrier_timeout=
1664 [NET] Specifies amount of time (in seconds) that
1665 netpoll should wait for a carrier. By default netpoll
1668 no387 [BUGS=X86-32] Tells the kernel to use the 387 maths
1669 emulation library even if a 387 maths coprocessor
1673 [HW] Never suspend the console
1674 Disable suspending of consoles during suspend and
1675 hibernate operations. Once disabled, debugging
1676 messages can reach various consoles while the rest
1677 of the system is being put to sleep (ie, while
1678 debugging driver suspend/resume hooks). This may
1679 not work reliably with all consoles, but is known
1680 to work with serial and VGA consoles.
1681 To facilitate more flexible debugging, we also add
1682 console_suspend, a printk module parameter to control
1683 it. Users could use console_suspend (usually
1684 /sys/module/printk/parameters/console_suspend) to
1685 turn on/off it dynamically.
1687 noaliencache [MM, NUMA, SLAB] Disables the allocation of alien
1688 caches in the slab allocator. Saves per-node memory,
1689 but will impact performance.
1693 noapic [SMP,APIC] Tells the kernel to not make use of any
1694 IOAPICs that may be present in the system.
1696 noautogroup Disable scheduler automatic task group creation.
1698 nobats [PPC] Do not use BATs for mapping kernel lowmem
1699 on "Classic" PPC cores.
1703 noclflush [BUGS=X86] Don't use the CLFLUSH instruction
1705 nodelayacct [KNL] Disable per-task delay accounting
1707 nodisconnect [HW,SCSI,M68K] Disables SCSI disconnects.
1709 nodsp [SH] Disable hardware DSP at boot time.
1711 noefi [X86] Disable EFI runtime services support.
1716 On X86-32 available only on PAE configured kernels.
1717 noexec=on: enable non-executable mappings (default)
1718 noexec=off: disable non-executable mappings
1721 Disable SMEP (Supervisor Mode Execution Protection)
1722 even if it is supported by processor.
1725 This affects only 32-bit executables.
1726 noexec32=on: enable non-executable mappings (default)
1727 read doesn't imply executable mappings
1728 noexec32=off: disable non-executable mappings
1729 read implies executable mappings
1731 nofpu [SH] Disable hardware FPU at boot time.
1733 nofxsr [BUGS=X86-32] Disables x86 floating point extended
1734 register save and restore. The kernel will only save
1735 legacy floating-point registers on task switch.
1737 noxsave [BUGS=X86] Disables x86 extended register state save
1738 and restore using xsave. The kernel will fallback to
1739 enabling legacy floating-point and sse state.
1741 nohlt [BUGS=ARM,SH] Tells the kernel that the sleep(SH) or
1742 wfi(ARM) instruction doesn't work correctly and not to
1743 use it. This is also useful when using JTAG debugger.
1745 no-hlt [BUGS=X86-32] Tells the kernel that the hlt
1746 instruction doesn't work correctly and not to
1749 no_file_caps Tells the kernel not to honor file capabilities. The
1750 only way then for a file to be executed with privilege
1751 is to be setuid root or executed by root.
1753 nohalt [IA-64] Tells the kernel not to use the power saving
1754 function PAL_HALT_LIGHT when idle. This increases
1755 power-consumption. On the positive side, it reduces
1756 interrupt wake-up latency, which may improve performance
1757 in certain environments such as networked servers or
1760 nohz= [KNL] Boottime enable/disable dynamic ticks
1761 Valid arguments: on, off
1764 noiotrap [SH] Disables trapped I/O port accesses.
1766 noirqdebug [X86-32] Disables the code which attempts to detect and
1767 disable unhandled interrupt sources.
1769 no_timer_check [X86,APIC] Disables the code which tests for
1770 broken timer IRQ sources.
1772 noisapnp [ISAPNP] Disables ISA PnP code.
1774 noinitrd [RAM] Tells the kernel not to load any configured
1777 nointremap [X86-64, Intel-IOMMU] Do not enable interrupt
1779 [Deprecated - use intremap=off]
1783 nojitter [IA-64] Disables jitter checking for ITC timers.
1785 no-kvmclock [X86,KVM] Disable paravirtualized KVM clock driver
1787 no-kvmapf [X86,KVM] Disable paravirtualized asynchronous page
1790 no-steal-acc [X86,KVM] Disable paravirtualized steal time accounting.
1791 steal time is computed, but won't influence scheduler
1794 nolapic [X86-32,APIC] Do not enable or use the local APIC.
1796 nolapic_timer [X86-32,APIC] Do not use the local APIC timer.
1798 noltlbs [PPC] Do not use large page/tlb entries for kernel
1799 lowmem mapping on PPC40x.
1801 nomca [IA-64] Disable machine check abort handling
1803 nomce [X86-32] Machine Check Exception
1805 nomfgpt [X86-32] Disable Multi-Function General Purpose
1806 Timer usage (for AMD Geode machines).
1808 nopat [X86] Disable PAT (page attribute table extension of
1809 pagetables) support.
1811 norandmaps Don't use address space randomization. Equivalent to
1812 echo 0 > /proc/sys/kernel/randomize_va_space
1814 noreplace-paravirt [X86,IA-64,PV_OPS] Don't patch paravirt_ops
1816 noreplace-smp [X86-32,SMP] Don't replace SMP instructions
1817 with UP alternatives
1819 noresidual [PPC] Don't use residual data on PReP machines.
1821 nordrand [X86] Disable the direct use of the RDRAND
1822 instruction even if it is supported by the
1823 processor. RDRAND is still available to user
1826 noresume [SWSUSP] Disables resume and restores original swap
1829 no-scroll [VGA] Disables scrollback.
1830 This is required for the Braillex ib80-piezo Braille
1831 reader made by F.H. Papenmeier (Germany).
1835 nosep [BUGS=X86-32] Disables x86 SYSENTER/SYSEXIT support.
1837 nosmp [SMP] Tells an SMP kernel to act as a UP kernel,
1838 and disable the IO APIC. legacy for "maxcpus=0".
1840 nosoftlockup [KNL] Disable the soft-lockup detector.
1842 nosync [HW,M68K] Disables sync negotiation for all devices.
1844 notsc [BUGS=X86-32] Disable Time Stamp Counter
1846 nousb [USB] Disable the USB subsystem
1848 nowatchdog [KNL] Disable the lockup detector (NMI watchdog).
1852 nox2apic [X86-64,APIC] Do not enable x2APIC mode.
1854 nptcg= [IA-64] Override max number of concurrent global TLB
1855 purges which is reported from either PAL_VM_SUMMARY or
1858 nr_cpus= [SMP] Maximum number of processors that an SMP kernel
1859 could support. nr_cpus=n : n >= 1 limits the kernel to
1860 supporting 'n' processors. Later in runtime you can not
1861 use hotplug cpu feature to put more cpu back to online.
1862 just like you compile the kernel NR_CPUS=n
1864 nr_uarts= [SERIAL] maximum number of UARTs to be registered.
1866 numa_zonelist_order= [KNL, BOOT] Select zonelist order for NUMA.
1867 one of ['zone', 'node', 'default'] can be specified
1868 This can be set from sysctl after boot.
1869 See Documentation/sysctl/vm.txt for details.
1871 ohci1394_dma=early [HW] enable debugging via the ohci1394 driver.
1872 See Documentation/debugging-via-ohci1394.txt for more
1875 olpc_ec_timeout= [OLPC] ms delay when issuing EC commands
1876 Rather than timing out after 20 ms if an EC
1877 command is not properly ACKed, override the length
1878 of the timeout. We have interrupts disabled while
1879 waiting for the ACK, so if this is set too high
1880 interrupts *may* be lost!
1882 omap_mux= [OMAP] Override bootloader pin multiplexing.
1883 Format: <mux_mode0.mode_name=value>...
1884 For example, to override I2C bus2:
1885 omap_mux=i2c2_scl.i2c2_scl=0x100,i2c2_sda.i2c2_sda=0x100
1887 oprofile.timer= [HW]
1888 Use timer interrupt instead of performance counters
1890 oprofile.cpu_type= Force an oprofile cpu type
1891 This might be useful if you have an older oprofile
1892 userland or if you want common events.
1893 Format: { arch_perfmon }
1894 arch_perfmon: [X86] Force use of architectural
1895 perfmon on Intel CPUs instead of the
1896 CPU specific event set.
1897 timer: [X86] Force use of architectural NMI
1898 timer mode (see also oprofile.timer
1899 for generic hr timer mode)
1900 [s390] Force legacy basic mode sampling
1901 (report cpu_type "timer")
1903 oops=panic Always panic on oopses. Default is to just kill the
1904 process, but there is a small probability of
1905 deadlocking the machine.
1906 This will also cause panics on machine check exceptions.
1907 Useful together with panic=30 to trigger a reboot.
1910 See Documentation/sound/oss/oss-parameters.txt
1912 panic= [KNL] Kernel behaviour on panic: delay <timeout>
1913 timeout > 0: seconds before rebooting
1914 timeout = 0: wait forever
1915 timeout < 0: reboot immediately
1918 parkbd.port= [HW] Parallel port number the keyboard adapter is
1919 connected to, default is 0.
1921 parkbd.mode= [HW] Parallel port keyboard adapter mode of operation,
1922 0 for XT, 1 for AT (default is AT).
1925 parport= [HW,PPT] Specify parallel ports. 0 disables.
1926 Format: { 0 | auto | 0xBBB[,IRQ[,DMA]] }
1927 Use 'auto' to force the driver to use any
1928 IRQ/DMA settings detected (the default is to
1929 ignore detected IRQ/DMA settings because of
1930 possible conflicts). You can specify the base
1931 address, IRQ, and DMA settings; IRQ and DMA
1932 should be numbers, or 'auto' (for using detected
1933 settings on that particular port), or 'nofifo'
1934 (to avoid using a FIFO even if it is detected).
1935 Parallel ports are assigned in the order they
1936 are specified on the command line, starting
1939 parport_init_mode= [HW,PPT]
1940 Configure VIA parallel port to operate in
1941 a specific mode. This is necessary on Pegasos
1942 computer where firmware has no options for setting
1943 up parallel port mode and sets it to spp.
1944 Currently this function knows 686a and 8231 chips.
1945 Format: [spp|ps2|epp|ecp|ecpepp]
1948 Halt all CPUs after the first oops has been printed for
1949 the specified number of seconds. This is to be used if
1950 your oopses keep scrolling off the screen.
1955 See header of drivers/block/paride/pcd.c.
1956 See also Documentation/blockdev/paride.txt.
1958 pci=option[,option...] [PCI] various PCI subsystem options:
1959 earlydump [X86] dump PCI config space before the kernel
1961 off [X86] don't probe for the PCI bus
1962 bios [X86-32] force use of PCI BIOS, don't access
1963 the hardware directly. Use this if your machine
1964 has a non-standard PCI host bridge.
1965 nobios [X86-32] disallow use of PCI BIOS, only direct
1966 hardware access methods are allowed. Use this
1967 if you experience crashes upon bootup and you
1968 suspect they are caused by the BIOS.
1969 conf1 [X86] Force use of PCI Configuration
1971 conf2 [X86] Force use of PCI Configuration
1973 noaer [PCIE] If the PCIEAER kernel config parameter is
1974 enabled, this kernel boot option can be used to
1975 disable the use of PCIE advanced error reporting.
1976 nodomains [PCI] Disable support for multiple PCI
1977 root domains (aka PCI segments, in ACPI-speak).
1978 nommconf [X86] Disable use of MMCONFIG for PCI
1980 check_enable_amd_mmconf [X86] check for and enable
1981 properly configured MMIO access to PCI
1982 config space on AMD family 10h CPU
1983 nomsi [MSI] If the PCI_MSI kernel config parameter is
1984 enabled, this kernel boot option can be used to
1985 disable the use of MSI interrupts system-wide.
1986 noioapicquirk [APIC] Disable all boot interrupt quirks.
1987 Safety option to keep boot IRQs enabled. This
1988 should never be necessary.
1989 ioapicreroute [APIC] Enable rerouting of boot IRQs to the
1990 primary IO-APIC for bridges that cannot disable
1991 boot IRQs. This fixes a source of spurious IRQs
1992 when the system masks IRQs.
1993 noioapicreroute [APIC] Disable workaround that uses the
1994 boot IRQ equivalent of an IRQ that connects to
1995 a chipset where boot IRQs cannot be disabled.
1996 The opposite of ioapicreroute.
1997 biosirq [X86-32] Use PCI BIOS calls to get the interrupt
1998 routing table. These calls are known to be buggy
1999 on several machines and they hang the machine
2000 when used, but on other computers it's the only
2001 way to get the interrupt routing table. Try
2002 this option if the kernel is unable to allocate
2003 IRQs or discover secondary PCI buses on your
2005 rom [X86] Assign address space to expansion ROMs.
2006 Use with caution as certain devices share
2007 address decoders between ROMs and other
2009 norom [X86] Do not assign address space to
2010 expansion ROMs that do not already have
2011 BIOS assigned address ranges.
2012 nobar [X86] Do not assign address space to the
2013 BARs that weren't assigned by the BIOS.
2014 irqmask=0xMMMM [X86] Set a bit mask of IRQs allowed to be
2015 assigned automatically to PCI devices. You can
2016 make the kernel exclude IRQs of your ISA cards
2018 pirqaddr=0xAAAAA [X86] Specify the physical address
2019 of the PIRQ table (normally generated
2020 by the BIOS) if it is outside the
2021 F0000h-100000h range.
2022 lastbus=N [X86] Scan all buses thru bus #N. Can be
2023 useful if the kernel is unable to find your
2024 secondary buses and you want to tell it
2025 explicitly which ones they are.
2026 assign-busses [X86] Always assign all PCI bus
2027 numbers ourselves, overriding
2028 whatever the firmware may have done.
2029 usepirqmask [X86] Honor the possible IRQ mask stored
2030 in the BIOS $PIR table. This is needed on
2031 some systems with broken BIOSes, notably
2032 some HP Pavilion N5400 and Omnibook XE3
2033 notebooks. This will have no effect if ACPI
2034 IRQ routing is enabled.
2035 noacpi [X86] Do not use ACPI for IRQ routing
2036 or for PCI scanning.
2037 use_crs [X86] Use PCI host bridge window information
2038 from ACPI. On BIOSes from 2008 or later, this
2039 is enabled by default. If you need to use this,
2040 please report a bug.
2041 nocrs [X86] Ignore PCI host bridge windows from ACPI.
2042 If you need to use this, please report a bug.
2043 routeirq Do IRQ routing for all PCI devices.
2044 This is normally done in pci_enable_device(),
2045 so this option is a temporary workaround
2046 for broken drivers that don't call it.
2047 skip_isa_align [X86] do not align io start addr, so can
2048 handle more pci cards
2049 firmware [ARM] Do not re-enumerate the bus but instead
2050 just use the configuration from the
2051 bootloader. This is currently used on
2052 IXP2000 systems where the bus has to be
2053 configured a certain way for adjunct CPUs.
2054 noearly [X86] Don't do any early type 1 scanning.
2055 This might help on some broken boards which
2056 machine check when some devices' config space
2057 is read. But various workarounds are disabled
2058 and some IOMMU drivers will not work.
2059 bfsort Sort PCI devices into breadth-first order.
2060 This sorting is done to get a device
2061 order compatible with older (<= 2.4) kernels.
2062 nobfsort Don't sort PCI devices into breadth-first order.
2063 cbiosize=nn[KMG] The fixed amount of bus space which is
2064 reserved for the CardBus bridge's IO window.
2065 The default value is 256 bytes.
2066 cbmemsize=nn[KMG] The fixed amount of bus space which is
2067 reserved for the CardBus bridge's memory
2068 window. The default value is 64 megabytes.
2071 [<order of align>@][<domain>:]<bus>:<slot>.<func>[; ...]
2072 Specifies alignment and device to reassign
2073 aligned memory resources.
2074 If <order of align> is not specified,
2075 PAGE_SIZE is used as alignment.
2076 PCI-PCI bridge can be specified, if resource
2077 windows need to be expanded.
2078 ecrc= Enable/disable PCIe ECRC (transaction layer
2079 end-to-end CRC checking).
2080 bios: Use BIOS/firmware settings. This is the
2084 realloc reallocate PCI resources if allocations done by BIOS
2087 pcie_aspm= [PCIE] Forcibly enable or disable PCIe Active State Power
2090 force Enable ASPM even on devices that claim not to support it.
2091 WARNING: Forcing ASPM on may cause system lockups.
2093 pcie_ports= [PCIE] PCIe ports handling:
2094 auto Ask the BIOS whether or not to use native PCIe services
2095 associated with PCIe ports (PME, hot-plug, AER). Use
2096 them only if that is allowed by the BIOS.
2097 native Use native PCIe services associated with PCIe ports
2099 compat Treat PCIe ports as PCI-to-PCI bridges, disable the PCIe
2102 pcie_pme= [PCIE,PM] Native PCIe PME signaling options:
2103 nomsi Do not use MSI for native PCIe PME signaling (this makes
2104 all PCIe root ports use INTx for all services).
2106 pcmv= [HW,PCMCIA] BadgePAD 4
2109 See Documentation/blockdev/paride.txt.
2111 pdcchassis= [PARISC,HW] Disable/Enable PDC Chassis Status codes at
2114 See arch/parisc/kernel/pdc_chassis.c
2116 percpu_alloc= Select which percpu first chunk allocator to use.
2117 Currently supported values are "embed" and "page".
2118 Archs may support subset or none of the selections.
2119 See comments in mm/percpu.c for details on each
2120 allocator. This parameter is primarily for debugging
2121 and performance comparison.
2124 See Documentation/blockdev/paride.txt.
2127 See Documentation/blockdev/paride.txt.
2129 pirq= [SMP,APIC] Manual mp-table setup
2130 See Documentation/x86/i386/IO-APIC.txt.
2132 plip= [PPT,NET] Parallel port network link
2133 Format: { parport<nr> | timid | 0 }
2134 See also Documentation/parport.txt.
2136 pmtmr= [X86] Manual setup of pmtmr I/O Port.
2137 Override pmtimer IOPort with a hex value.
2141 Enable PNP debug messages (depends on the
2142 CONFIG_PNP_DEBUG_MESSAGES option). Change at run-time
2143 via /sys/module/pnp/parameters/debug. We always show
2144 current resource usage; turning this on also shows
2145 possible settings and some assignment information.
2151 { on | off | curr | res | no-curr | no-res }
2154 [ISAPNP] Exclude IRQs for the autoconfiguration
2157 [ISAPNP] Exclude DMAs for the autoconfiguration
2159 pnp_reserve_io= [ISAPNP] Exclude I/O ports for the autoconfiguration
2160 Ranges are in pairs (I/O port base and size).
2163 [ISAPNP] Exclude memory regions for the
2165 Ranges are in pairs (memory base and size).
2167 ports= [IP_VS_FTP] IPVS ftp helper module
2169 Up to 8 (IP_VS_APP_MAX_PORTS) ports
2171 Format: <port>,<port>....
2173 print-fatal-signals=
2174 [KNL] debug: print fatal signals
2176 If enabled, warn about various signal handling
2177 related application anomalies: too many signals,
2178 too many POSIX.1 timers, fatal signals causing a
2181 If you hit the warning due to signal overflow,
2182 you might want to try "ulimit -i unlimited".
2186 printk.time= Show timing data prefixed to each printk message line
2187 Format: <bool> (1/Y/y=enable, 0/N/n=disable)
2189 processor.max_cstate= [HW,ACPI]
2190 Limit processor to maximum C-state
2191 max_cstate=9 overrides any DMI blacklist limit.
2193 processor.nocst [HW,ACPI]
2194 Ignore the _CST method to determine C-states,
2195 instead using the legacy FADT method
2197 profile= [KNL] Enable kernel profiling via /proc/profile
2198 Format: [schedule,]<number>
2199 Param: "schedule" - profile schedule points.
2200 Param: <number> - step/bucket size as a power of 2 for
2201 statistical time based profiling.
2202 Param: "sleep" - profile D-state sleeping (millisecs).
2203 Requires CONFIG_SCHEDSTATS
2204 Param: "kvm" - profile VM exits.
2206 prompt_ramdisk= [RAM] List of RAM disks to prompt for floppy disk
2208 See Documentation/blockdev/ramdisk.txt.
2210 psmouse.proto= [HW,MOUSE] Highest PS2 mouse protocol extension to
2211 probe for; one of (bare|imps|exps|lifebook|any).
2212 psmouse.rate= [HW,MOUSE] Set desired mouse report rate, in reports
2214 psmouse.resetafter= [HW,MOUSE]
2215 Try to reset the device after so many bad packets
2218 [HW,MOUSE] Set desired mouse resolution, in dpi.
2219 psmouse.smartscroll=
2220 [HW,MOUSE] Controls Logitech smartscroll autorepeat.
2221 0 = disabled, 1 = enabled (default).
2223 pstore.backend= Specify the name of the pstore backend to use
2226 See Documentation/blockdev/paride.txt.
2229 [KNL] Number of legacy pty's. Overwrites compiled-in
2232 quiet [KNL] Disable most log messages
2237 See Documentation/md.txt.
2239 ramdisk_blocksize= [RAM]
2240 See Documentation/blockdev/ramdisk.txt.
2242 ramdisk_size= [RAM] Sizes of RAM disks in kilobytes
2243 See Documentation/blockdev/ramdisk.txt.
2245 rcupdate.blimit= [KNL,BOOT]
2246 Set maximum number of finished RCU callbacks to process
2249 rcupdate.qhimark= [KNL,BOOT]
2250 Set threshold of queued
2251 RCU callbacks over which batch limiting is disabled.
2253 rcupdate.qlowmark= [KNL,BOOT]
2254 Set threshold of queued RCU callbacks below which
2255 batch limiting is re-enabled.
2259 Run specified binary instead of /init from the ramdisk,
2260 used for early userspace startup. See initrd.
2262 reboot= [BUGS=X86-32,BUGS=ARM,BUGS=IA-64] Rebooting mode
2263 Format: <reboot_mode>[,<reboot_mode2>[,...]]
2264 See arch/*/kernel/reboot.c or arch/*/kernel/process.c
2267 [KNL, SMP] Set scheduler's default relax_domain_level.
2268 See Documentation/cgroups/cpusets.txt.
2270 reserve= [KNL,BUGS] Force the kernel to ignore some iomem area
2272 reservetop= [X86-32]
2274 Reserves a hole at the top of the kernel virtual
2279 Set the amount of memory to reserve for BIOS at
2280 the bottom of the address space.
2282 reset_devices [KNL] Force drivers to reset the underlying device
2283 during initialization.
2286 Specify the partition device for software suspend
2288 resume_offset= [SWSUSP]
2289 Specify the offset from the beginning of the partition
2290 given by "resume=" at which the swap header is located,
2291 in <PAGE_SIZE> units (needed only for swap files).
2292 See Documentation/power/swsusp-and-swap-files.txt
2294 resumedelay= [HIBERNATION] Delay (in seconds) to pause before attempting to
2295 read the resume files
2297 resumewait [HIBERNATION] Wait (indefinitely) for resume device to show up.
2298 Useful for devices that are detected asynchronously
2299 (e.g. USB and MMC devices).
2301 hibernate= [HIBERNATION]
2302 noresume Don't check if there's a hibernation image
2303 present during boot.
2304 nocompress Don't compress/decompress hibernation images.
2306 retain_initrd [RAM] Keep initrd memory after extraction
2308 rhash_entries= [KNL,NET]
2309 Set number of hash buckets for route cache
2311 riscom8= [HW,SERIAL]
2312 Format: <io_board1>[,<io_board2>[,...<io_boardN>]]
2314 ro [KNL] Mount root device read-only on boot
2316 root= [KNL] Root filesystem
2317 See name_to_dev_t comment in init/do_mounts.c.
2319 rootdelay= [KNL] Delay (in seconds) to pause before attempting to
2320 mount the root filesystem
2322 rootflags= [KNL] Set root filesystem mount option string
2324 rootfstype= [KNL] Set root filesystem type
2326 rootwait [KNL] Wait (indefinitely) for root device to show up.
2327 Useful for devices that are detected asynchronously
2328 (e.g. USB and MMC devices).
2330 rw [KNL] Mount root device read-write on boot
2332 S [KNL] Run init in single mode
2335 See drivers/net/irda/sa1100_ir.c.
2337 sbni= [NET] Granch SBNI12 leased line adapter
2339 sched_debug [KNL] Enables verbose scheduler debug messages.
2341 security= [SECURITY] Choose a security module to enable at boot.
2342 If this boot parameter is not specified, only the first
2343 security module asking for security registration will be
2344 loaded. An invalid security module name will be treated
2345 as if no module has been chosen.
2347 selinux= [SELINUX] Disable or enable SELinux at boot time.
2348 Format: { "0" | "1" }
2349 See security/selinux/Kconfig help text.
2352 Default value is set via kernel config option.
2353 If enabled at boot time, /selinux/disable can be used
2354 later to disable prior to initial policy load.
2356 apparmor= [APPARMOR] Disable or enable AppArmor at boot time
2357 Format: { "0" | "1" }
2358 See security/apparmor/Kconfig help text
2361 Default value is set via kernel config option.
2363 serialnumber [BUGS=X86-32]
2366 Maximal number of shapers.
2368 show_msr= [x86] show boot-time MSR settings
2369 Format: { <integer> }
2370 Show boot-time (BIOS-initialized) MSR settings.
2371 The parameter means the number of CPUs to show,
2372 for example 1 means boot CPU only.
2379 slub_debug[=options[,slabs]] [MM, SLUB]
2380 Enabling slub_debug allows one to determine the
2381 culprit if slab objects become corrupted. Enabling
2382 slub_debug can create guard zones around objects and
2383 may poison objects when not in use. Also tracks the
2384 last alloc / free. For more information see
2385 Documentation/vm/slub.txt.
2387 slub_max_order= [MM, SLUB]
2388 Determines the maximum allowed order for slabs.
2389 A high setting may cause OOMs due to memory
2390 fragmentation. For more information see
2391 Documentation/vm/slub.txt.
2393 slub_min_objects= [MM, SLUB]
2394 The minimum number of objects per slab. SLUB will
2395 increase the slab order up to slub_max_order to
2396 generate a sufficiently large slab able to contain
2397 the number of objects indicated. The higher the number
2398 of objects the smaller the overhead of tracking slabs
2399 and the less frequently locks need to be acquired.
2400 For more information see Documentation/vm/slub.txt.
2402 slub_min_order= [MM, SLUB]
2403 Determines the mininum page order for slabs. Must be
2404 lower than slub_max_order.
2405 For more information see Documentation/vm/slub.txt.
2407 slub_nomerge [MM, SLUB]
2408 Disable merging of slabs with similar size. May be
2409 necessary if there is some reason to distinguish
2410 allocs to different slabs. Debug options disable
2411 merging on their own.
2412 For more information see Documentation/vm/slub.txt.
2415 Format: <io1>[,<io2>[,...,<io8>]]
2417 smp-alt-once [X86-32,SMP] On a hotplug CPU system, only
2418 attempt to substitute SMP alternatives once at boot.
2420 smsc-ircc2.nopnp [HW] Don't use PNP to discover SMC devices
2421 smsc-ircc2.ircc_cfg= [HW] Device configuration I/O port
2422 smsc-ircc2.ircc_sir= [HW] SIR base I/O port
2423 smsc-ircc2.ircc_fir= [HW] FIR base I/O port
2424 smsc-ircc2.ircc_irq= [HW] IRQ line
2425 smsc-ircc2.ircc_dma= [HW] DMA channel
2426 smsc-ircc2.ircc_transceiver= [HW] Transceiver type:
2427 0: Toshiba Satellite 1800 (GP data pin select)
2428 1: Fast pin select (default)
2432 [KNL] Should the soft-lockup detector generate panics.
2435 sonypi.*= [HW] Sony Programmable I/O Control Device driver
2436 See Documentation/laptops/sonypi.txt
2438 specialix= [HW,SERIAL] Specialix multi-serial port adapter
2439 See Documentation/serial/specialix.txt.
2441 spia_io_base= [HW,MTD]
2447 Enabled the stack tracer on boot up.
2451 Set the STI (builtin display/keyboard on the HP-PARISC
2452 machines) console (graphic card) which should be used
2453 as the initial boot-console.
2454 See also comment in drivers/video/console/sticore.c.
2457 See comment in drivers/video/console/sticore.c.
2460 Format: bpp:<bpp1>[:<bpp2>[:<bpp3>...]]
2462 sunrpc.min_resvport=
2463 sunrpc.max_resvport=
2465 SunRPC servers often require that client requests
2466 originate from a privileged port (i.e. a port in the
2467 range 0 < portnr < 1024).
2468 An administrator who wishes to reserve some of these
2469 ports for other uses may adjust the range that the
2470 kernel's sunrpc client considers to be privileged
2471 using these two parameters to set the minimum and
2472 maximum port values.
2476 Control how the NFS server code allocates CPUs to
2477 service thread pools. Depending on how many NICs
2478 you have and where their interrupts are bound, this
2479 option will affect which CPUs will do NFS serving.
2480 Note: this parameter cannot be changed while the
2481 NFS server is running.
2483 auto the server chooses an appropriate mode
2484 automatically using heuristics
2485 global a single global pool contains all CPUs
2486 percpu one pool for each CPU
2487 pernode one pool for each NUMA node (equivalent
2488 to global on non-NUMA machines)
2490 sunrpc.tcp_slot_table_entries=
2491 sunrpc.udp_slot_table_entries=
2493 Sets the upper limit on the number of simultaneous
2494 RPC calls that can be sent from the client to a
2495 server. Increasing these values may allow you to
2496 improve throughput, but will also increase the
2497 amount of memory reserved for use by the client.
2500 [KNL] Enable accounting of swap in memory resource
2501 controller if no parameter or 1 is given or disable
2502 it if 0 is given (See Documentation/cgroups/memory.txt)
2504 swiotlb= [IA-64] Number of I/O TLB slabs
2508 sysfs.deprecated=0|1 [KNL]
2509 Enable/disable old style sysfs layout for old udev
2510 on older distributions. When this option is enabled
2511 very new udev will not work anymore. When this option
2512 is disabled (or CONFIG_SYSFS_DEPRECATED not compiled)
2513 in older udev will not work anymore.
2514 Default depends on CONFIG_SYSFS_DEPRECATED_V2 set in
2515 the kernel configuration.
2517 sysrq_always_enabled
2519 Ignore sysrq setting - this boot parameter will
2520 neutralize any effect of /proc/sys/kernel/sysrq.
2521 Useful for debugging.
2525 test_suspend= [SUSPEND]
2526 Specify "mem" (for Suspend-to-RAM) or "standby" (for
2527 standby suspend) as the system sleep state to briefly
2528 enter during system startup. The system is woken from
2529 this state using a wakeup-capable RTC alarm.
2531 thash_entries= [KNL,NET]
2532 Set number of hash buckets for TCP connection
2534 thermal.act= [HW,ACPI]
2535 -1: disable all active trip points in all thermal zones
2536 <degrees C>: override all lowest active trip points
2538 thermal.crt= [HW,ACPI]
2539 -1: disable all critical trip points in all thermal zones
2540 <degrees C>: override all critical trip points
2542 thermal.nocrt= [HW,ACPI]
2543 Set to disable actions on ACPI thermal zone
2544 critical and hot trip points.
2546 thermal.off= [HW,ACPI]
2547 1: disable ACPI thermal control
2549 thermal.psv= [HW,ACPI]
2550 -1: disable all passive trip points
2551 <degrees C>: override all passive trip points to this
2554 thermal.tzp= [HW,ACPI]
2555 Specify global default ACPI thermal zone polling rate
2556 <deci-seconds>: poll all this frequency
2557 0: no polling (default)
2560 Force threading of all interrupt handlers except those
2561 marked explicitely IRQF_NO_THREAD.
2565 Specify if the kernel should make use of the cpu
2566 topology information if the hardware supports this.
2567 The scheduler will make use of this information and
2568 e.g. base its process migration decisions on it.
2573 tpm_suspend_pcr=[HW,TPM]
2574 Format: integer pcr id
2575 Specify that at suspend time, the tpm driver
2576 should extend the specified pcr with zeros,
2577 as a workaround for some chips which fail to
2578 flush the last written pcr on TPM_SaveState.
2579 This will guarantee that all the other pcrs
2582 trace_buf_size=nn[KMG]
2583 [FTRACE] will set tracing buffer size.
2585 trace_event=[event-list]
2586 [FTRACE] Set and start specified trace events in order
2587 to facilitate early boot debugging.
2588 See also Documentation/trace/events.txt
2590 tsc= Disable clocksource stability checks for TSC.
2592 [x86] reliable: mark tsc clocksource as reliable, this
2593 disables clocksource verification at runtime, as well
2594 as the stability checks done at bootup. Used to enable
2595 high-resolution timer mode on older hardware, and in
2596 virtualized environment.
2597 [x86] noirqtime: Do not use TSC to do irq accounting.
2598 Used to run time disable IRQ_TIME_ACCOUNTING on any
2599 platforms where RDTSC is slow and this accounting
2602 turbografx.map[2|3]= [HW,JOY]
2603 TurboGraFX parallel port interface
2605 <port#>,<js1>,<js2>,<js3>,<js4>,<js5>,<js6>,<js7>
2606 See also Documentation/input/joystick-parport.txt
2608 udbg-immortal [PPC] When debugging early kernel crashes that
2609 happen after console_init() and before a proper
2610 console driver takes over, this boot options might
2611 help "seeing" what's going on.
2613 uhash_entries= [KNL,NET]
2614 Set number of hash buckets for UDP/UDP-Lite connections
2617 [USB] Ignore overcurrent events (default N).
2618 Some badly-designed motherboards generate lots of
2619 bogus events, for ports that aren't wired to
2620 anything. Set this parameter to avoid log spamming.
2621 Note that genuine overcurrent events won't be
2625 [X86] Cause panic on unknown NMI.
2627 usbcore.authorized_default=
2628 [USB] Default USB device authorization:
2629 (default -1 = authorized except for wireless USB,
2630 0 = not authorized, 1 = authorized)
2632 usbcore.autosuspend=
2633 [USB] The autosuspend time delay (in seconds) used
2634 for newly-detected USB devices (default 2). This
2635 is the time required before an idle device will be
2636 autosuspended. Devices for which the delay is set
2637 to a negative value won't be autosuspended at all.
2639 usbcore.usbfs_snoop=
2640 [USB] Set to log all usbfs traffic (default 0 = off).
2642 usbcore.blinkenlights=
2643 [USB] Set to cycle leds on hubs (default 0 = off).
2645 usbcore.old_scheme_first=
2646 [USB] Start with the old device initialization
2647 scheme (default 0 = off).
2649 usbcore.usbfs_memory_mb=
2650 [USB] Memory limit (in MB) for buffers allocated by
2651 usbfs (default = 16, 0 = max = 2047).
2653 usbcore.use_both_schemes=
2654 [USB] Try the other device initialization scheme
2655 if the first one fails (default 1 = enabled).
2657 usbcore.initial_descriptor_timeout=
2658 [USB] Specifies timeout for the initial 64-byte
2659 USB_REQ_GET_DESCRIPTOR request in milliseconds
2660 (default 5000 = 5.0 seconds).
2663 [USBHID] The interval which mice are to be polled at.
2665 usb-storage.delay_use=
2666 [UMS] The delay in seconds before a new device is
2667 scanned for Logical Units (default 5).
2670 [UMS] A list of quirks entries to supplement or
2671 override the built-in unusual_devs list. List
2672 entries are separated by commas. Each entry has
2673 the form VID:PID:Flags where VID and PID are Vendor
2674 and Product ID values (4-digit hex numbers) and
2675 Flags is a set of characters, each corresponding
2676 to a common usb-storage quirk flag as follows:
2677 a = SANE_SENSE (collect more than 18 bytes
2679 b = BAD_SENSE (don't collect more than 18
2680 bytes of sense data);
2681 c = FIX_CAPACITY (decrease the reported
2682 device capacity by one sector);
2683 d = NO_READ_DISC_INFO (don't use
2684 READ_DISC_INFO command);
2685 e = NO_READ_CAPACITY_16 (don't use
2686 READ_CAPACITY_16 command);
2687 h = CAPACITY_HEURISTICS (decrease the
2688 reported device capacity by one
2689 sector if the number is odd);
2690 i = IGNORE_DEVICE (don't bind to this
2692 l = NOT_LOCKABLE (don't try to lock and
2693 unlock ejectable media);
2694 m = MAX_SECTORS_64 (don't transfer more
2695 than 64 sectors = 32 KB at a time);
2696 n = INITIAL_READ10 (force a retry of the
2697 initial READ(10) command);
2698 o = CAPACITY_OK (accept the capacity
2699 reported by the device);
2700 r = IGNORE_RESIDUE (the device reports
2701 bogus residue values);
2702 s = SINGLE_LUN (the device has only one
2704 w = NO_WP_DETECT (don't test whether the
2705 medium is write-protected).
2706 Example: quirks=0419:aaf5:rl,0421:0433:rc
2708 user_debug= [KNL,ARM]
2710 See arch/arm/Kconfig.debug help text.
2711 1 - undefined instruction events
2713 4 - invalid data aborts
2716 Example: user_debug=31
2719 [X86] Flags controlling user PTE allocations.
2721 nohigh = do not allocate PTE pages in
2722 HIGHMEM regardless of setting
2726 vdso=2: enable compat VDSO (default with COMPAT_VDSO)
2727 vdso=1: enable VDSO (default)
2728 vdso=0: disable VDSO mapping
2731 vdso32=2: enable compat VDSO (default with COMPAT_VDSO)
2732 vdso32=1: enable 32-bit VDSO (default)
2733 vdso32=0: disable 32-bit VDSO mapping
2736 vector=percpu: enable percpu vector domain
2738 video= [FB] Frame buffer configuration
2739 See Documentation/fb/modedb.txt.
2741 vga= [BOOT,X86-32] Select a particular video mode
2742 See Documentation/x86/boot.txt and
2743 Documentation/svga.txt.
2744 Use vga=ask for menu.
2745 This is actually a boot loader parameter; the value is
2746 passed to the kernel using a special protocol.
2748 vmalloc=nn[KMG] [KNL,BOOT] Forces the vmalloc area to have an exact
2749 size of <nn>. This can be used to increase the
2750 minimum size (128MB on x86). It can also be used to
2751 decrease the size and leave more room for directly
2754 vmhalt= [KNL,S390] Perform z/VM CP command after system halt.
2757 vmpanic= [KNL,S390] Perform z/VM CP command after kernel panic.
2760 vmpoff= [KNL,S390] Perform z/VM CP command after power off.
2764 Controls the behavior of vsyscalls (i.e. calls to
2765 fixed addresses of 0xffffffffff600x00 from legacy
2766 code). Most statically-linked binaries and older
2767 versions of glibc use these calls. Because these
2768 functions are at fixed addresses, they make nice
2769 targets for exploits that can control RIP.
2771 emulate [default] Vsyscalls turn into traps and are
2772 emulated reasonably safely.
2774 native Vsyscalls are native syscall instructions.
2775 This is a little bit faster than trapping
2776 and makes a few dynamic recompilers work
2777 better than they would in emulation mode.
2778 It also makes exploits much easier to write.
2780 none Vsyscalls don't work at all. This makes
2781 them quite hard to use for exploits but
2782 might break your system.
2784 vt.cur_default= [VT] Default cursor shape.
2785 Format: 0xCCBBAA, where AA, BB, and CC are the same as
2786 the parameters of the <Esc>[?A;B;Cc escape sequence;
2787 see VGA-softcursor.txt. Default: 2 = underline.
2789 vt.default_blu= [VT]
2790 Format: <blue0>,<blue1>,<blue2>,...,<blue15>
2791 Change the default blue palette of the console.
2792 This is a 16-member array composed of values
2795 vt.default_grn= [VT]
2796 Format: <green0>,<green1>,<green2>,...,<green15>
2797 Change the default green palette of the console.
2798 This is a 16-member array composed of values
2801 vt.default_red= [VT]
2802 Format: <red0>,<red1>,<red2>,...,<red15>
2803 Change the default red palette of the console.
2804 This is a 16-member array composed of values
2810 Set system-wide default UTF-8 mode for all tty's.
2811 Default is 1, i.e. UTF-8 mode is enabled for all
2812 newly opened terminals.
2814 vt.global_cursor_default=
2817 Set system-wide default for whether a cursor
2818 is shown on new VTs. Default is -1,
2819 i.e. cursors will be created by default unless
2820 overridden by individual drivers. 0 will hide
2821 cursors, 1 will display them.
2823 watchdog timers [HW,WDT] For information on watchdog timers,
2824 see Documentation/watchdog/watchdog-parameters.txt
2825 or other driver-specific files in the
2826 Documentation/watchdog/ directory.
2828 x2apic_phys [X86-64,APIC] Use x2apic physical mode instead of
2829 default x2apic cluster mode on platforms
2832 x86_mrst_timer= [X86-32,APBT]
2833 Choose timer option for x86 Moorestown MID platform.
2834 Two valid options are apbt timer only and lapic timer
2835 plus one apbt timer for broadcast timer.
2836 x86_mrst_timer=apbt_only | lapic_and_apbt
2838 xd= [HW,XT] Original XT pre-IDE (RLL encoded) disks.
2839 xd_geo= See header of drivers/block/xd.c.
2841 xen_emul_unplug= [HW,X86,XEN]
2842 Unplug Xen emulated devices
2843 Format: [unplug0,][unplug1]
2844 ide-disks -- unplug primary master IDE devices
2845 aux-ide-disks -- unplug non-primary-master IDE devices
2846 nics -- unplug network devices
2847 all -- unplug all emulated devices (NICs and IDE disks)
2848 unnecessary -- unplugging emulated devices is
2849 unnecessary even if the host did not respond to
2851 never -- do not unplug even if version check succeeds
2853 xirc2ps_cs= [NET,PCMCIA]
2855 <irq>,<irq_mask>,<io>,<full_duplex>,<do_sound>,<lockup_hack>[,<irq2>[,<irq3>[,<irq4>]]]
2857 ______________________________________________________________________
2861 Add more DRM drivers.
projects / firefly-linux-kernel-4.4.55.git / blob