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 FB The frame buffer device is enabled.
53 FTRACE Function tracing enabled.
54 GCOV GCOV profiling is enabled.
55 HW Appropriate hardware is enabled.
56 IA-64 IA-64 architecture is enabled.
57 IMA Integrity measurement architecture is enabled.
58 IOSCHED More than one I/O scheduler is enabled.
59 IP_PNP IP DHCP, BOOTP, or RARP is enabled.
60 IPV6 IPv6 support is enabled.
61 ISAPNP ISA PnP code is enabled.
62 ISDN Appropriate ISDN support is enabled.
63 JOY Appropriate joystick support is enabled.
64 KGDB Kernel debugger support is enabled.
65 KVM Kernel Virtual Machine support is enabled.
66 LIBATA Libata driver is enabled
67 LP Printer support is enabled.
68 LOOP Loopback device support is enabled.
69 M68k M68k architecture is enabled.
70 These options have more detailed description inside of
71 Documentation/m68k/kernel-options.txt.
72 MCA MCA bus support is enabled.
73 MDA MDA console support is enabled.
74 MIPS MIPS architecture is enabled.
75 MOUSE Appropriate mouse support is enabled.
76 MSI Message Signaled Interrupts (PCI).
77 MTD MTD (Memory Technology Device) support is enabled.
78 NET Appropriate network support is enabled.
79 NUMA NUMA support is enabled.
80 NFS Appropriate NFS support is enabled.
81 OSS OSS sound support is enabled.
82 PV_OPS A paravirtualized kernel is enabled.
83 PARIDE The ParIDE (parallel port IDE) subsystem is enabled.
84 PARISC The PA-RISC architecture is enabled.
85 PCI PCI bus support is enabled.
86 PCIE PCI Express support is enabled.
87 PCMCIA The PCMCIA subsystem is enabled.
88 PNP Plug & Play support is enabled.
89 PPC PowerPC architecture is enabled.
90 PPT Parallel port support is enabled.
91 PS2 Appropriate PS/2 support is enabled.
92 RAM RAM disk support is enabled.
93 S390 S390 architecture is enabled.
94 SCSI Appropriate SCSI support is enabled.
95 A lot of drivers have their options described inside
96 the Documentation/scsi/ sub-directory.
97 SECURITY Different security models are enabled.
98 SELINUX SELinux support is enabled.
99 APPARMOR AppArmor support is enabled.
100 SERIAL Serial support is enabled.
101 SH SuperH architecture is enabled.
102 SMP The kernel is an SMP kernel.
103 SPARC Sparc architecture is enabled.
104 SWSUSP Software suspend (hibernation) is enabled.
105 SUSPEND System suspend states are enabled.
106 TPM TPM drivers are enabled.
107 TS Appropriate touchscreen support is enabled.
108 UMS USB Mass Storage support is enabled.
109 USB USB support is enabled.
110 USBHID USB Human Interface Device support is enabled.
111 V4L Video For Linux support is enabled.
112 VGA The VGA console has been enabled.
113 VT Virtual terminal support is enabled.
114 WDT Watchdog support is enabled.
115 XT IBM PC/XT MFM hard disk support is enabled.
116 X86-32 X86-32, aka i386 architecture is enabled.
117 X86-64 X86-64 architecture is enabled.
118 More X86-64 boot options can be found in
119 Documentation/x86/x86_64/boot-options.txt .
120 X86 Either 32-bit or 64-bit x86 (same as X86-32+X86-64)
121 XEN Xen support is enabled
123 In addition, the following text indicates that the option:
125 BUGS= Relates to possible processor bugs on the said processor.
126 KNL Is a kernel start-up parameter.
127 BOOT Is a boot loader parameter.
129 Parameters denoted with BOOT are actually interpreted by the boot
130 loader, and have no meaning to the kernel directly.
131 Do not modify the syntax of boot loader parameters without extreme
132 need or coordination with <Documentation/x86/boot.txt>.
134 There are also arch-specific kernel-parameters not documented here.
135 See for example <Documentation/x86/x86_64/boot-options.txt>.
137 Note that ALL kernel parameters listed below are CASE SENSITIVE, and that
138 a trailing = on the name of any parameter states that that parameter will
139 be entered as an environment variable, whereas its absence indicates that
140 it will appear as a kernel argument readable via /proc/cmdline by programs
141 running once the system is up.
143 The number of kernel parameters is not limited, but the length of the
144 complete command line (parameters including spaces etc.) is limited to
145 a fixed number of characters. This limit depends on the architecture
146 and is between 256 and 4096 characters. It is defined in the file
147 ./include/asm/setup.h as COMMAND_LINE_SIZE.
149 Finally, the [KMG] suffix is commonly described after a number of kernel
150 parameter values. These 'K', 'M', and 'G' letters represent the _binary_
151 multipliers 'Kilo', 'Mega', and 'Giga', equalling 2^10, 2^20, and 2^30
152 bytes respectively. Such letter suffixes can also be entirely omitted.
156 Advanced Configuration and Power Interface
157 Format: { force | off | strict | noirq | rsdt }
158 force -- enable ACPI if default was off
159 off -- disable ACPI if default was on
160 noirq -- do not use ACPI for IRQ routing
161 strict -- Be less tolerant of platforms that are not
162 strictly ACPI specification compliant.
163 rsdt -- prefer RSDT over (default) XSDT
164 copy_dsdt -- copy DSDT to memory
166 See also Documentation/power/pm.txt, pci=noacpi
168 acpi_rsdp= [ACPI,EFI,KEXEC]
169 Pass the RSDP address to the kernel, mostly used
170 on machines running EFI runtime service to boot the
171 second kernel for kdump.
173 acpi_apic_instance= [ACPI, IOAPIC]
175 2: use 2nd APIC table, if available
176 1,0: use 1st APIC table
179 acpi_backlight= [HW,ACPI]
180 acpi_backlight=vendor
182 If set to vendor, prefer vendor specific driver
183 (e.g. thinkpad_acpi, sony_acpi, etc.) instead
184 of the ACPI video.ko driver.
186 acpi.debug_layer= [HW,ACPI,ACPI_DEBUG]
187 acpi.debug_level= [HW,ACPI,ACPI_DEBUG]
189 CONFIG_ACPI_DEBUG must be enabled to produce any ACPI
190 debug output. Bits in debug_layer correspond to a
191 _COMPONENT in an ACPI source file, e.g.,
192 #define _COMPONENT ACPI_PCI_COMPONENT
193 Bits in debug_level correspond to a level in
194 ACPI_DEBUG_PRINT statements, e.g.,
195 ACPI_DEBUG_PRINT((ACPI_DB_INFO, ...
196 The debug_level mask defaults to "info". See
197 Documentation/acpi/debug.txt for more information about
198 debug layers and levels.
200 Enable processor driver info messages:
201 acpi.debug_layer=0x20000000
202 Enable PCI/PCI interrupt routing info messages:
203 acpi.debug_layer=0x400000
204 Enable AML "Debug" output, i.e., stores to the Debug
205 object while interpreting AML:
206 acpi.debug_layer=0xffffffff acpi.debug_level=0x2
207 Enable all messages related to ACPI hardware:
208 acpi.debug_layer=0x2 acpi.debug_level=0xffffffff
210 Some values produce so much output that the system is
211 unusable. The "log_buf_len" parameter may be useful
212 if you need to capture more output.
214 acpi_irq_balance [HW,ACPI]
215 ACPI will balance active IRQs
218 acpi_irq_nobalance [HW,ACPI]
219 ACPI will not move active IRQs (default)
222 acpi_irq_isa= [HW,ACPI] If irq_balance, mark listed IRQs used by ISA
223 Format: <irq>,<irq>...
225 acpi_irq_pci= [HW,ACPI] If irq_balance, clear listed IRQs for
227 Format: <irq>,<irq>...
229 acpi_no_auto_ssdt [HW,ACPI] Disable automatic loading of SSDT
231 acpi_os_name= [HW,ACPI] Tell ACPI BIOS the name of the OS
232 Format: To spoof as Windows 98: ="Microsoft Windows"
234 acpi_osi= [HW,ACPI] Modify list of supported OS interface strings
235 acpi_osi="string1" # add string1 -- only one string
236 acpi_osi="!string2" # remove built-in string2
237 acpi_osi= # disable all strings
240 Override the pmtimer bug detection: force the kernel
241 to assume that this machine's pmtimer latches its value
242 and always returns good values.
244 acpi_sci= [HW,ACPI] ACPI System Control Interrupt trigger mode
245 Format: { level | edge | high | low }
247 acpi_serialize [HW,ACPI] force serialization of AML methods
249 acpi_skip_timer_override [HW,ACPI]
250 Recognize and ignore IRQ0/pin2 Interrupt Override.
251 For broken nForce2 BIOS resulting in XT-PIC timer.
253 acpi_sleep= [HW,ACPI] Sleep options
254 Format: { s3_bios, s3_mode, s3_beep, s4_nohwsig,
255 old_ordering, nonvs, sci_force_enable }
256 See Documentation/power/video.txt for information on
258 s3_beep is for debugging; it makes the PC's speaker beep
259 as soon as the kernel's real-mode entry point is called.
260 s4_nohwsig prevents ACPI hardware signature from being
261 used during resume from hibernation.
262 old_ordering causes the ACPI 1.0 ordering of the _PTS
263 control method, with respect to putting devices into
264 low power states, to be enforced (the ACPI 2.0 ordering
265 of _PTS is used by default).
266 nonvs prevents the kernel from saving/restoring the
267 ACPI NVS memory during suspend/hibernation and resume.
268 sci_force_enable causes the kernel to set SCI_EN directly
269 on resume from S1/S3 (which is against the ACPI spec,
270 but some broken systems don't work without it).
272 acpi_use_timer_override [HW,ACPI]
273 Use timer override. For some broken Nvidia NF5 boards
274 that require a timer override, but don't have HPET
276 acpi_enforce_resources= [ACPI]
277 { strict | lax | no }
278 Check for resource conflicts between native drivers
279 and ACPI OperationRegions (SystemIO and SystemMemory
280 only). IO ports and memory declared in ACPI might be
281 used by the ACPI subsystem in arbitrary AML code and
282 can interfere with legacy drivers.
283 strict (default): access to resources claimed by ACPI
284 is denied; legacy drivers trying to access reserved
285 resources will fail to bind to device using them.
286 lax: access to resources claimed by ACPI is allowed;
287 legacy drivers trying to access reserved resources
288 will bind successfully but a warning message is logged.
289 no: ACPI OperationRegions are not marked as reserved,
290 no further checks are performed.
292 add_efi_memmap [EFI; X86] Include EFI memory map in
293 kernel's map of available physical RAM.
296 { off | try_unsupported }
297 off: disable AGP support
298 try_unsupported: try to drive unsupported chipsets
299 (may crash computer or cause data corruption)
302 See Documentation/sound/alsa/alsa-parameters.txt
305 Allow the default userspace alignment fault handler
306 behaviour to be specified. Bit 0 enables warnings,
307 bit 1 enables fixups, and bit 2 sends a segfault.
309 amd_iommu= [HW,X86-84]
310 Pass parameters to the AMD IOMMU driver in the system.
312 fullflush - enable flushing of IO/TLB entries when
313 they are unmapped. Otherwise they are
314 flushed before they will be reused, which
316 off - do not initialize any AMD IOMMU found in
319 amijoy.map= [HW,JOY] Amiga joystick support
320 Map of devices attached to JOY0DAT and JOY1DAT
322 See also Documentation/kernel/input/joystick.txt
324 analog.map= [HW,JOY] Analog joystick and gamepad support
325 Specifies type or capabilities of an analog joystick
326 connected to one of 16 gameports
327 Format: <type1>,<type2>,..<type16>
330 Power management functions (SPARCstation-4/5 + deriv.)
332 Disable APC CPU standby support. SPARCstation-Fox does
333 not play well with APC CPU idle - disable it if you have
334 APC and your system crashes randomly.
336 apic= [APIC,X86-32] Advanced Programmable Interrupt Controller
337 Change the output verbosity whilst booting
338 Format: { quiet (default) | verbose | debug }
339 Change the amount of debugging information output
340 when initialising the APIC and IO-APIC components.
343 See Documentation/networking/ipv6.txt.
345 show_lapic= [APIC,X86] Advanced Programmable Interrupt Controller
346 Limit apic dumping. The parameter defines the maximal
347 number of local apics being dumped. Also it is possible
348 to set it to "all" by meaning -- no limit here.
349 Format: { 1 (default) | 2 | ... | all }.
350 The parameter valid if only apic=debug or
351 apic=verbose is specified.
352 Example: apic=debug show_lapic=all
354 apm= [APM] Advanced Power Management
355 See header of arch/x86/kernel/apm_32.c.
357 arcrimi= [HW,NET] ARCnet - "RIM I" (entirely mem-mapped) cards
358 Format: <io>,<irq>,<nodeID>
362 atarimouse= [HW,MOUSE] Atari Mouse
364 atkbd.extra= [HW] Enable extra LEDs and keys on IBM RapidAccess,
365 EzKey and similar keyboards
367 atkbd.reset= [HW] Reset keyboard during initialization
369 atkbd.set= [HW] Select keyboard code set
370 Format: <int> (2 = AT (default), 3 = PS/2)
372 atkbd.scroll= [HW] Enable scroll wheel on MS Office and similar
375 atkbd.softraw= [HW] Choose between synthetic and real raw mode
376 Format: <bool> (0 = real, 1 = synthetic (default))
378 atkbd.softrepeat= [HW]
379 Use software keyboard repeat
383 baycom_epp= [HW,AX25]
386 baycom_par= [HW,AX25] BayCom Parallel Port AX.25 Modem
388 See header of drivers/net/hamradio/baycom_par.c.
390 baycom_ser_fdx= [HW,AX25]
391 BayCom Serial Port AX.25 Modem (Full Duplex Mode)
392 Format: <io>,<irq>,<mode>[,<baud>]
393 See header of drivers/net/hamradio/baycom_ser_fdx.c.
395 baycom_ser_hdx= [HW,AX25]
396 BayCom Serial Port AX.25 Modem (Half Duplex Mode)
397 Format: <io>,<irq>,<mode>
398 See header of drivers/net/hamradio/baycom_ser_hdx.c.
400 boot_delay= Milliseconds to delay each printk during boot.
401 Values larger than 10 seconds (10000) are changed to
405 bootmem_debug [KNL] Enable bootmem allocator debug messages.
407 bttv.card= [HW,V4L] bttv (bt848 + bt878 based grabber cards)
408 bttv.radio= Most important insmod options are available as
410 bttv.pll= See Documentation/video4linux/bttv/Insmod-options
411 bttv.tuner= and Documentation/video4linux/bttv/CARDLIST
413 bulk_remove=off [PPC] This parameter disables the use of the pSeries
414 firmware feature for flushing multiple hpte entries
417 c101= [NET] Moxa C101 synchronous serial card
419 cachesize= [BUGS=X86-32] Override level 2 CPU cache size detection.
420 Sometimes CPU hardware bugs make them report the cache
421 size incorrectly. The kernel will attempt work arounds
422 to fix known problems, but for some CPUs it is not
423 possible to determine what the correct size should be.
424 This option provides an override for these situations.
427 [SECURITY] Disable capabilities. This would normally
428 be used only if an alternative security model is to be
429 configured. Potentially dangerous and should only be
430 used if you are entirely sure of the consequences.
432 ccw_timeout_log [S390]
433 See Documentation/s390/CommonIO for details.
435 cgroup_disable= [KNL] Disable a particular controller
436 Format: {name of the controller(s) to disable}
437 {Currently supported controllers - "memory"}
439 checkreqprot [SELINUX] Set initial checkreqprot flag value.
440 Format: { "0" | "1" }
441 See security/selinux/Kconfig help text.
442 0 -- check protection applied by kernel (includes
443 any implied execute protection).
444 1 -- check protection requested by application.
445 Default value is set via a kernel config option.
446 Value can be changed at runtime via
447 /selinux/checkreqprot.
450 See Documentation/s390/CommonIO for details.
452 clock= [BUGS=X86-32, HW] gettimeofday clocksource override.
454 Forces specified clocksource (if available) to be used
455 when calculating gettimeofday(). If specified
456 clocksource is not available, it defaults to PIT.
457 Format: { pit | tsc | cyclone | pmtmr }
459 clocksource= Override the default clocksource
461 Override the default clocksource and use the clocksource
462 with the name specified.
463 Some clocksource names to choose from, depending on
465 [all] jiffies (this is the base, fallback clocksource)
467 [ARM] imx_timer1,OSTS,netx_timer,mpu_timer2,
468 pxa_timer,timer3,32k_counter,timer0_1
470 [X86-32] pit,hpet,tsc;
471 scx200_hrt on Geode; cyclone on IBM x440
479 clearcpuid=BITNUM [X86]
480 Disable CPUID feature X for the kernel. See
481 arch/x86/include/asm/cpufeature.h for the valid bit
482 numbers. Note the Linux specific bits are not necessarily
483 stable over kernel options, but the vendor specific
485 Also note that user programs calling CPUID directly
486 or using the feature without checking anything
487 will still see it. This just prevents it from
488 being used by the kernel or shown in /proc/cpuinfo.
489 Also note the kernel might malfunction if you disable
492 cmo_free_hint= [PPC] Format: { yes | no }
493 Specify whether pages are marked as being inactive
494 when they are freed. This is used in CMO environments
495 to determine OS memory pressure for page stealing by
499 code_bytes [X86] How many bytes of object code to print
504 com20020= [HW,NET] ARCnet - COM20020 chipset
506 <io>[,<irq>[,<nodeID>[,<backplane>[,<ckp>[,<timeout>]]]]]
508 com90io= [HW,NET] ARCnet - COM90xx chipset (IO-mapped buffers)
512 ARCnet - COM90xx chipset (memory-mapped buffers)
513 Format: <io>[,<irq>[,<memstart>]]
515 condev= [HW,S390] console device
518 console= [KNL] Output console device and options.
520 tty<n> Use the virtual console device <n>.
524 Use the specified serial port. The options are of
525 the form "bbbbpnf", where "bbbb" is the baud rate,
526 "p" is parity ("n", "o", or "e"), "n" is number of
527 bits, and "f" is flow control ("r" for RTS or
528 omit it). Default is "9600n8".
530 See Documentation/serial-console.txt for more
532 Documentation/networking/netconsole.txt for an
535 uart[8250],io,<addr>[,options]
536 uart[8250],mmio,<addr>[,options]
537 Start an early, polled-mode console on the 8250/16550
538 UART at the specified I/O port or MMIO address,
539 switching to the matching ttyS device later. The
540 options are the same as for ttyS, above.
542 If the device connected to the port is not a TTY but a braille
543 device, prepend "brl," before the device type, for instance
545 For now, only VisioBraille is supported.
547 consoleblank= [KNL] The console blank (screen saver) timeout in
548 seconds. Defaults to 10*60 = 10mins. A value of 0
549 disables the blank timer.
552 [KNL] Change the default value for
553 /proc/<pid>/coredump_filter.
554 See also Documentation/filesystems/proc.txt.
556 cpuidle.off=1 [CPU_IDLE]
557 disable the cpuidle sub-system
559 cpcihp_generic= [HW,PCI] Generic port I/O CompactPCI driver
561 <first_slot>,<last_slot>,<port>,<enum_bit>[,<debug>]
563 crashkernel=size[KMG][@offset[KMG]]
564 [KNL] Using kexec, Linux can switch to a 'crash kernel'
565 upon panic. This parameter reserves the physical
566 memory region [offset, offset + size] for that kernel
567 image. If '@offset' is omitted, then a suitable offset
568 is selected automatically. Check
569 Documentation/kdump/kdump.txt for further details.
571 crashkernel=range1:size1[,range2:size2,...][@offset]
572 [KNL] Same as above, but depends on the memory
573 in the running system. The syntax of range is
574 start-[end] where start and end are both
575 a memory unit (amount[KMG]). See also
576 Documentation/kdump/kdump.txt for an example.
581 cs89x0_media= [HW,NET]
582 Format: { rj45 | aui | bnc }
585 See header of drivers/s390/block/dasd_devmap.c.
587 db9.dev[2|3]= [HW,JOY] Multisystem joystick support via parallel port
588 (one device per port)
589 Format: <port#>,<type>
590 See also Documentation/input/joystick-parport.txt
592 ddebug_query= [KNL,DYNAMIC_DEBUG] Enable debug messages at early boot
593 time. See Documentation/dynamic-debug-howto.txt for
596 debug [KNL] Enable kernel debugging (events log level).
599 [KNL] verbose self-tests
601 Print debugging info while doing the locking API
603 We default to 0 (no extra messages), setting it to
604 1 will print _a lot_ more information - normally
605 only useful to kernel developers.
607 debug_objects [KNL] Enable object debugging
610 [KNL] Disable object debugging
612 debugpat [X86] Enable PAT debugging
614 decnet.addr= [HW,NET]
615 Format: <area>[,<node>]
616 See also Documentation/networking/decnet.txt.
619 [same as hugepagesz=] The size of the default
620 HugeTLB page size. This is the size represented by
621 the legacy /proc/ hugepages APIs, used for SHM, and
622 default size when mounting hugetlbfs filesystems.
623 Defaults to the default architecture's huge page size
627 Set number of hash buckets for dentry cache.
630 IO parameters + enable/disable command.
632 digiepca= [HW,SERIAL]
633 See drivers/char/README.epca and
634 Documentation/serial/digiepca.txt.
637 See Documentation/networking/ipv6.txt.
639 disable_ddw [PPC/PSERIES]
640 Disable Dynamic DMA Window support. Use this if
641 to workaround buggy firmware.
644 See Documentation/networking/ipv6.txt.
646 disable_mtrr_cleanup [X86]
647 The kernel tries to adjust MTRR layout from continuous
648 to discrete, to make X server driver able to add WB
649 entry later. This parameter disables that.
651 disable_mtrr_trim [X86, Intel and AMD only]
652 By default the kernel will trim any uncacheable
653 memory out of your available memory pool based on
654 MTRR settings. This parameter disables that behavior,
655 possibly causing your machine to run very slowly.
657 disable_timer_pin_1 [X86]
658 Disable PIN 1 of APIC timer
659 Can be useful to work around chipset bugs.
661 dma_debug=off If the kernel is compiled with DMA_API_DEBUG support,
662 this option disables the debugging code at boot.
664 dma_debug_entries=<number>
665 This option allows to tune the number of preallocated
666 entries for DMA-API debugging code. One entry is
667 required per DMA-API allocation. Use this if the
668 DMA-API debugging code disables itself because the
669 architectural default is too low.
671 dma_debug_driver=<driver_name>
672 With this option the DMA-API debugging driver
673 filter feature can be enabled at boot time. Just
674 pass the driver to filter for as the parameter.
675 The filter can be disabled or changed to another
676 driver later using sysfs.
680 earlycon= [KNL] Output early console device and options.
681 uart[8250],io,<addr>[,options]
682 uart[8250],mmio,<addr>[,options]
683 uart[8250],mmio32,<addr>[,options]
684 Start an early, polled-mode console on the 8250/16550
685 UART at the specified I/O port or MMIO address.
686 MMIO inter-register address stride is either 8-bit
687 (mmio) or 32-bit (mmio32).
688 The options are the same as for ttyS, above.
690 earlyprintk= [X86,SH,BLACKFIN]
692 earlyprintk=serial[,ttySn[,baudrate]]
693 earlyprintk=ttySn[,baudrate]
694 earlyprintk=dbgp[debugController#]
696 Append ",keep" to not disable it when the real console
699 Only vga or serial or usb debug port at a time.
701 Currently only ttyS0 and ttyS1 are supported.
703 Interaction with the standard serial driver is not
706 The VGA output is eventually overwritten by the real
709 ekgdboc= [X86,KGDB] Allow early kernel console debugging
712 This is designed to be used in conjunction with
713 the boot argument: earlyprintk=vga
716 Format: {"off" | "on" | "skip[mbr]"}
718 eisa_irq_edge= [PARISC,HW]
719 See header of drivers/parisc/eisa.c.
722 See comment before function elanfreq_setup() in
723 arch/x86/kernel/cpu/cpufreq/elanfreq.c.
726 Format: {"cfq" | "deadline" | "noop"}
727 See Documentation/block/as-iosched.txt and
728 Documentation/block/deadline-iosched.txt for details.
730 elfcorehdr= [IA-64,PPC,SH,X86]
731 Specifies physical address of start of kernel core
732 image elf header. Generally kexec loader will
733 pass this option to capture kernel.
734 See Documentation/kdump/kdump.txt for details.
736 enable_mtrr_cleanup [X86]
737 The kernel tries to adjust MTRR layout from continuous
738 to discrete, to make X server driver able to add WB
739 entry later. This parameter enables that.
741 enable_timer_pin_1 [X86]
742 Enable PIN 1 of APIC timer
743 Can be useful to work around chipset bugs
744 (in particular on some ATI chipsets).
745 The kernel tries to set a reasonable default.
747 enforcing [SELINUX] Set initial enforcing status.
749 See security/selinux/Kconfig help text.
750 0 -- permissive (log only, no denials).
751 1 -- enforcing (deny and log).
753 Value can be changed at runtime via /selinux/enforce.
756 Disable Error Record Serialization Table (ERST)
759 ether= [HW,NET] Ethernet cards parameters
760 This option is obsoleted by the "netdev=" option, which
761 has equivalent usage. See its documentation for details.
765 fail_make_request=[KNL]
766 General fault injection mechanism.
767 Format: <interval>,<probability>,<space>,<times>
768 See also /Documentation/fault-injection/.
771 See Documentation/blockdev/floppy.txt.
773 force_pal_cache_flush
774 [IA-64] Avoid check_sal_cache_flush which may hang on
775 buggy SAL_CACHE_FLUSH implementations. Using this
776 parameter will force ia64_sal_cache_flush to call
777 ia64_pal_cache_flush instead of SAL_CACHE_FLUSH.
780 [FTRACE] will set and start the specified tracer
781 as early as possible in order to facilitate early
784 ftrace_dump_on_oops[=orig_cpu]
785 [FTRACE] will dump the trace buffers on oops.
786 If no parameter is passed, ftrace will dump
787 buffers of all CPUs, but if you pass orig_cpu, it will
788 dump only the buffer of the CPU that triggered the
791 ftrace_filter=[function-list]
792 [FTRACE] Limit the functions traced by the function
793 tracer at boot up. function-list is a comma separated
794 list of functions. This list can be changed at run
795 time by the set_ftrace_filter file in the debugfs
798 ftrace_notrace=[function-list]
799 [FTRACE] Do not trace the functions specified in
800 function-list. This list can be changed at run time
801 by the set_ftrace_notrace file in the debugfs
804 ftrace_graph_filter=[function-list]
805 [FTRACE] Limit the top level callers functions traced
806 by the function graph tracer at boot up.
807 function-list is a comma separated list of functions
808 that can be changed at run time by the
809 set_graph_function file in the debugfs tracing directory.
812 [HW,JOY] Multisystem joystick and NES/SNES/PSX pad
813 support via parallel port (up to 5 devices per port)
814 Format: <port#>,<pad1>,<pad2>,<pad3>,<pad4>,<pad5>
815 See also Documentation/input/joystick-parport.txt
819 gart_fix_e820= [X86_64] disable the fix e820 for K8 GART
823 gcov_persist= [GCOV] When non-zero (default), profiling data for
824 kernel modules is saved and remains accessible via
825 debugfs, even when the module is unloaded/reloaded.
826 When zero, profiling data is discarded and associated
827 debugfs files are removed at module unload time.
829 gpt [EFI] Forces disk with valid GPT signature but
830 invalid Protective MBR to be treated as GPT.
832 hashdist= [KNL,NUMA] Large hashes allocated during boot
833 are distributed across NUMA nodes. Defaults on
834 for 64-bit NUMA, off otherwise.
835 Format: 0 | 1 (for off | on)
837 hcl= [IA-64] SGI's Hardware Graph compatibility layer
839 hd= [EIDE] (E)IDE hard drive subsystem geometry
840 Format: <cyl>,<head>,<sect>
843 Disable Hardware Error Source Table (HEST) support;
844 corresponding firmware-first mode error processing
845 logic will be disabled.
847 highmem=nn[KMG] [KNL,BOOT] forces the highmem zone to have an exact
848 size of <nn>. This works even on boxes that have no
849 highmem otherwise. This also works to reduce highmem
850 size on bigger boxes.
852 highres= [KNL] Enable/disable high resolution timer mode.
853 Valid parameters: "on", "off"
857 See Documentation/isdn/README.HiSax.
861 hpet= [X86-32,HPET] option to control HPET usage
862 Format: { enable (default) | disable | force |
864 disable: disable HPET and use PIT instead
865 force: allow force enabled of undocumented chips (ICH4,
867 verbose: show contents of HPET registers during setup
869 hugepages= [HW,X86-32,IA-64] HugeTLB pages to allocate at boot.
870 hugepagesz= [HW,IA-64,PPC,X86-64] The size of the HugeTLB pages.
871 On x86-64 and powerpc, this option can be specified
872 multiple times interleaved with hugepages= to reserve
873 huge pages of different sizes. Valid pages sizes on
874 x86-64 are 2M (when the CPU supports "pse") and 1G
875 (when the CPU supports the "pdpe1gb" cpuinfo flag)
876 Note that 1GB pages can only be allocated at boot time
877 using hugepages= and not freed afterwards.
879 hvc_iucv= [S390] Number of z/VM IUCV hypervisor console (HVC)
880 terminal devices. Valid values: 0..8
881 hvc_iucv_allow= [S390] Comma-separated list of z/VM user IDs.
882 If specified, z/VM IUCV HVC accepts connections
883 from listed z/VM user IDs only.
886 Do not unregister boot console at start. This is only
887 useful for debugging when something happens in the window
888 between unregistering the boot console and initializing
891 i2c_bus= [HW] Override the default board specific I2C bus speed
892 or register an additional I2C bus that is not
893 registered from board initialization code.
897 i8042.debug [HW] Toggle i8042 debug mode
898 i8042.direct [HW] Put keyboard port into non-translated mode
899 i8042.dumbkbd [HW] Pretend that controller can only read data from
900 keyboard and cannot control its state
901 (Don't attempt to blink the leds)
902 i8042.noaux [HW] Don't check for auxiliary (== mouse) port
903 i8042.nokbd [HW] Don't check/create keyboard port
904 i8042.noloop [HW] Disable the AUX Loopback command while probing
906 i8042.nomux [HW] Don't check presence of an active multiplexing
908 i8042.nopnp [HW] Don't use ACPIPnP / PnPBIOS to discover KBD/AUX
910 i8042.notimeout [HW] Ignore timeout condition signalled by conroller
911 i8042.reset [HW] Reset the controller during init and cleanup
912 i8042.unlock [HW] Unlock (ignore) the keylock
916 i8k.ignore_dmi [HW] Continue probing hardware even if DMI data
917 indicates that the driver is running on unsupported
919 i8k.force [HW] Activate i8k driver even if SMM BIOS signature
920 does not match list of supported models.
922 [HW] Report power status in /proc/i8k
923 (disabled by default)
924 i8k.restricted [HW] Allow controlling fans only if SYS_ADMIN
928 Format: <io>[,<membase>[,<icn_id>[,<icn_id2>]]]
930 ide-core.nodma= [HW] (E)IDE subsystem
931 Format: =0.0 to prevent dma on hda, =0.1 hdb =1.0 hdc
932 .vlb_clock .pci_clock .noflush .nohpa .noprobe .nowerr
933 .cdrom .chs .ignore_cable are additional options
934 See Documentation/ide/ide.txt.
936 ide-pci-generic.all-generic-ide [HW] (E)IDE subsystem
937 Claim all unknown PCI IDE storage controllers.
940 Format: idle=poll, idle=mwait, idle=halt, idle=nomwait
941 Poll forces a polling idle loop that can slightly
942 improve the performance of waking up a idle CPU, but
943 will use a lot of power and make the system run hot.
945 idle=mwait: On systems which support MONITOR/MWAIT but
946 the kernel chose to not use it because it doesn't save
947 as much power as a normal idle loop, use the
948 MONITOR/MWAIT idle loop anyways. Performance should be
949 the same as idle=poll.
950 idle=halt: Halt is forced to be used for CPU idle.
951 In such case C2/C3 won't be used again.
952 idle=nomwait: Disable mwait for CPU C-states
954 ignore_loglevel [KNL]
955 Ignore loglevel setting - this will print /all/
956 kernel messages to the console. Useful for debugging.
959 Set number of hash buckets for inode cache.
962 Format: { "0" | "1" }
963 0 -- integrity auditing messages. (Default)
964 1 -- enable informational integrity auditing messages.
967 Format: { "sha1" | "md5" }
971 Load a policy which meets the needs of the Trusted
972 Computing Base. This means IMA will measure all
973 programs exec'd, files mmap'd for exec, and all files
974 opened for read by uid=0.
978 Run specified binary instead of /sbin/init as init
981 initcall_debug [KNL] Trace initcalls as they are executed. Useful
982 for working out where the kernel is dying during
985 initrd= [BOOT] Specify the location of the initial ramdisk
987 inport.irq= [HW] Inport (ATI XL and Microsoft) busmouse driver
990 intel_iommu= [DMAR] Intel IOMMU driver (DMAR) option
992 Enable intel iommu driver.
994 Disable intel iommu driver.
995 igfx_off [Default Off]
996 By default, gfx is mapped as normal device. If a gfx
997 device has a dedicated DMAR unit, the DMAR unit is
998 bypassed by not enabling DMAR with this option. In
999 this case, gfx device will use physical address for
1002 With this option iommu will not optimize to look
1003 for io virtual address below 32-bit forcing dual
1004 address cycle on pci bus for cards supporting greater
1005 than 32-bit addressing. The default is to look
1006 for translation below 32-bit and if not available
1007 then look in the higher range.
1008 strict [Default Off]
1009 With this option on every unmap_single operation will
1010 result in a hardware IOTLB flush operation as opposed
1011 to batching them for performance.
1012 sp_off [Default Off]
1013 By default, super page will be supported if Intel IOMMU
1014 has the capability. With this option, super page will
1016 intremap= [X86-64, Intel-IOMMU]
1017 Format: { on (default) | off | nosid }
1018 on enable Interrupt Remapping (default)
1019 off disable Interrupt Remapping
1020 nosid disable Source ID checking
1024 iomem= Disable strict checking of access to MMIO memory
1025 strict regions from userspace.
1041 io7= [HW] IO7 for Marvel based alpha systems
1042 See comment before marvel_specify_io7 in
1043 arch/alpha/kernel/core_marvel.c.
1045 io_delay= [X86] I/O delay method
1047 Standard port 0x80 based delay
1049 Alternate port 0xed based delay (needed on some systems)
1051 Simple two microseconds delay
1056 See Documentation/filesystems/nfs/nfsroot.txt.
1058 ip2= [HW] Set IO/IRQ pairs for up to 4 IntelliPort boards
1059 See comment before ip2_setup() in
1060 drivers/char/ip2/ip2base.c.
1063 When an interrupt is not handled search all handlers
1064 for it. Intended to get systems with badly broken
1068 When an interrupt is not handled search all handlers
1069 for it. Also check all handlers each timer
1070 interrupt. Intended to get systems with badly broken
1074 Format: <RDP>,<reset>,<pci_scan>,<verbosity>
1076 isolcpus= [KNL,SMP] Isolate CPUs from the general scheduler.
1078 <cpu number>,...,<cpu number>
1080 <cpu number>-<cpu number>
1081 (must be a positive range in ascending order)
1083 <cpu number>,...,<cpu number>-<cpu number>
1085 This option can be used to specify one or more CPUs
1086 to isolate from the general SMP balancing and scheduling
1087 algorithms. You can move a process onto or off an
1088 "isolated" CPU via the CPU affinity syscalls or cpuset.
1089 <cpu number> begins at 0 and the maximum value is
1090 "number of CPUs in system - 1".
1092 This option is the preferred way to isolate CPUs. The
1093 alternative -- manually setting the CPU mask of all
1094 tasks in the system -- can cause problems and
1095 suboptimal load balancer performance.
1099 js= [HW,JOY] Analog joystick
1100 See Documentation/input/joystick.txt.
1104 kernelcore=nn[KMG] [KNL,X86,IA-64,PPC] This parameter
1105 specifies the amount of memory usable by the kernel
1106 for non-movable allocations. The requested amount is
1107 spread evenly throughout all nodes in the system. The
1108 remaining memory in each node is used for Movable
1109 pages. In the event, a node is too small to have both
1110 kernelcore and Movable pages, kernelcore pages will
1111 take priority and other nodes will have a larger number
1112 of kernelcore pages. The Movable zone is used for the
1113 allocation of pages that may be reclaimed or moved
1114 by the page migration subsystem. This means that
1115 HugeTLB pages may not be allocated from this zone.
1116 Note that allocations like PTEs-from-HighMem still
1117 use the HighMem zone if it exists, and the Normal
1118 zone if it does not.
1120 kgdbdbgp= [KGDB,HW] kgdb over EHCI usb debug port.
1121 Format: <Controller#>[,poll interval]
1122 The controller # is the number of the ehci usb debug
1123 port as it is probed via PCI. The poll interval is
1124 optional and is the number seconds in between
1125 each poll cycle to the debug port in case you need
1126 the functionality for interrupting the kernel with
1127 gdb or control-c on the dbgp connection. When
1128 not using this parameter you use sysrq-g to break into
1129 the kernel debugger.
1131 kgdboc= [KGDB,HW] kgdb over consoles.
1132 Requires a tty driver that supports console polling,
1133 or a supported polling keyboard driver (non-usb).
1134 Serial only format: <serial_device>[,baud]
1135 keyboard only format: kbd
1136 keyboard and serial format: kbd,<serial_device>[,baud]
1137 Optional Kernel mode setting:
1138 kms, kbd format: kms,kbd
1139 kms, kbd and serial format: kms,kbd,<ser_dev>[,baud]
1141 kgdbwait [KGDB] Stop kernel execution and enter the
1142 kernel debugger at the earliest opportunity.
1144 kmac= [MIPS] korina ethernet MAC address.
1145 Configure the RouterBoard 532 series on-chip
1146 Ethernet adapter MAC address.
1148 kmemleak= [KNL] Boot-time kmemleak enable/disable
1149 Valid arguments: on, off
1152 kstack=N [X86] Print N words from the kernel stack
1155 kvm.ignore_msrs=[KVM] Ignore guest accesses to unhandled MSRs.
1156 Default is 0 (don't ignore, but inject #GP)
1158 kvm.oos_shadow= [KVM] Disable out-of-sync shadow paging.
1159 Default is 1 (enabled)
1161 kvm.mmu_audit= [KVM] This is a R/W parameter which allows audit
1165 kvm-amd.nested= [KVM,AMD] Allow nested virtualization in KVM/SVM.
1166 Default is 1 (enabled)
1168 kvm-amd.npt= [KVM,AMD] Disable nested paging (virtualized MMU)
1170 Default is 1 (enabled) if in 64-bit or 32-bit PAE mode.
1172 kvm-intel.ept= [KVM,Intel] Disable extended page tables
1173 (virtualized MMU) support on capable Intel chips.
1174 Default is 1 (enabled)
1176 kvm-intel.emulate_invalid_guest_state=
1177 [KVM,Intel] Enable emulation of invalid guest states
1178 Default is 0 (disabled)
1180 kvm-intel.flexpriority=
1181 [KVM,Intel] Disable FlexPriority feature (TPR shadow).
1182 Default is 1 (enabled)
1185 [KVM,Intel] Enable VMX nesting (nVMX).
1186 Default is 0 (disabled)
1188 kvm-intel.unrestricted_guest=
1189 [KVM,Intel] Disable unrestricted guest feature
1190 (virtualized real and unpaged mode) on capable
1191 Intel chips. Default is 1 (enabled)
1193 kvm-intel.vpid= [KVM,Intel] Disable Virtual Processor Identification
1194 feature (tagged TLBs) on capable Intel chips.
1195 Default is 1 (enabled)
1201 lapic [X86-32,APIC] Enable the local APIC even if BIOS
1204 lapic_timer_c2_ok [X86,APIC] trust the local apic timer
1207 libata.dma= [LIBATA] DMA control
1208 libata.dma=0 Disable all PATA and SATA DMA
1209 libata.dma=1 PATA and SATA Disk DMA only
1210 libata.dma=2 ATAPI (CDROM) DMA only
1211 libata.dma=4 Compact Flash DMA only
1212 Combinations also work, so libata.dma=3 enables DMA
1213 for disks and CDROMs, but not CFs.
1215 libata.ignore_hpa= [LIBATA] Ignore HPA limit
1216 libata.ignore_hpa=0 keep BIOS limits (default)
1217 libata.ignore_hpa=1 ignore limits, using full disk
1219 libata.noacpi [LIBATA] Disables use of ACPI in libata suspend/resume
1223 libata.force= [LIBATA] Force configurations. The format is comma
1224 separated list of "[ID:]VAL" where ID is
1225 PORT[.DEVICE]. PORT and DEVICE are decimal numbers
1226 matching port, link or device. Basically, it matches
1227 the ATA ID string printed on console by libata. If
1228 the whole ID part is omitted, the last PORT and DEVICE
1229 values are used. If ID hasn't been specified yet, the
1230 configuration applies to all ports, links and devices.
1232 If only DEVICE is omitted, the parameter applies to
1233 the port and all links and devices behind it. DEVICE
1234 number of 0 either selects the first device or the
1235 first fan-out link behind PMP device. It does not
1236 select the host link. DEVICE number of 15 selects the
1237 host link and device attached to it.
1239 The VAL specifies the configuration to force. As long
1240 as there's no ambiguity shortcut notation is allowed.
1241 For example, both 1.5 and 1.5G would work for 1.5Gbps.
1242 The following configurations can be forced.
1244 * Cable type: 40c, 80c, short40c, unk, ign or sata.
1245 Any ID with matching PORT is used.
1247 * SATA link speed limit: 1.5Gbps or 3.0Gbps.
1249 * Transfer mode: pio[0-7], mwdma[0-4] and udma[0-7].
1250 udma[/][16,25,33,44,66,100,133] notation is also
1253 * [no]ncq: Turn on or off NCQ.
1255 * nohrst, nosrst, norst: suppress hard, soft
1258 * dump_id: dump IDENTIFY data.
1260 If there are multiple matching configurations changing
1261 the same attribute, the last one is used.
1263 memblock=debug [KNL] Enable memblock debug messages.
1265 load_ramdisk= [RAM] List of ramdisks to load from floppy
1266 See Documentation/blockdev/ramdisk.txt.
1268 lockd.nlm_grace_period=P [NFS] Assign grace period.
1271 lockd.nlm_tcpport=N [NFS] Assign TCP port.
1274 lockd.nlm_timeout=T [NFS] Assign timeout value.
1277 lockd.nlm_udpport=M [NFS] Assign UDP port.
1280 logibm.irq= [HW,MOUSE] Logitech Bus Mouse Driver
1283 loglevel= All Kernel Messages with a loglevel smaller than the
1284 console loglevel will be printed to the console. It can
1285 also be changed with klogd or other programs. The
1286 loglevels are defined as follows:
1288 0 (KERN_EMERG) system is unusable
1289 1 (KERN_ALERT) action must be taken immediately
1290 2 (KERN_CRIT) critical conditions
1291 3 (KERN_ERR) error conditions
1292 4 (KERN_WARNING) warning conditions
1293 5 (KERN_NOTICE) normal but significant condition
1294 6 (KERN_INFO) informational
1295 7 (KERN_DEBUG) debug-level messages
1297 log_buf_len=n[KMG] Sets the size of the printk ring buffer,
1298 in bytes. n must be a power of two. The default
1299 size is set in the kernel config file.
1301 logo.nologo [FB] Disables display of the built-in Linux logo.
1302 This may be used to provide more screen space for
1303 kernel log messages and is useful when debugging
1304 kernel boot problems.
1306 lp=0 [LP] Specify parallel ports to use, e.g,
1307 lp=port[,port...] lp=none,parport0 (lp0 not configured, lp1 uses
1308 lp=reset first parallel port). 'lp=0' disables the
1309 lp=auto printer driver. 'lp=reset' (which can be
1310 specified in addition to the ports) causes
1311 attached printers to be reset. Using
1312 lp=port1,port2,... specifies the parallel ports
1313 to associate lp devices with, starting with
1314 lp0. A port specification may be 'none' to skip
1315 that lp device, or a parport name such as
1316 'parport0'. Specifying 'lp=auto' instead of a
1317 port specification list means that device IDs
1318 from each port should be examined, to see if
1319 an IEEE 1284-compliant printer is attached; if
1320 so, the driver will manage that printer.
1321 See also header of drivers/char/lp.c.
1324 Sets loops_per_jiffy to given constant, thus avoiding
1325 time-consuming boot-time autodetection (up to 250 ms per
1326 CPU). 0 enables autodetection (default). To determine
1327 the correct value for your kernel, boot with normal
1328 autodetection and see what value is printed. Note that
1329 on SMP systems the preset will be applied to all CPUs,
1330 which is likely to cause problems if your CPUs need
1331 significantly divergent settings. An incorrect value
1332 will cause delays in the kernel to be wrong, leading to
1333 unpredictable I/O errors and other breakage. Although
1334 unlikely, in the extreme case this might damage your
1338 Format: <io>,<irq>,<dma>
1340 machvec= [IA-64] Force the use of a particular machine-vector
1341 (machvec) in a generic kernel.
1342 Example: machvec=hpzx1_swiotlb
1344 machtype= [Loongson] Share the same kernel image file between different
1346 Example: machtype=lemote-yeeloong-2f-7inch
1348 max_addr=nn[KMG] [KNL,BOOT,ia64] All physical memory greater
1349 than or equal to this physical address is ignored.
1351 maxcpus= [SMP] Maximum number of processors that an SMP kernel
1352 should make use of. maxcpus=n : n >= 0 limits the
1353 kernel to using 'n' processors. n=0 is a special case,
1354 it is equivalent to "nosmp", which also disables
1357 max_loop= [LOOP] The number of loop block devices that get
1358 (loop.max_loop) unconditionally pre-created at init time. The default
1359 number is configured by BLK_DEV_LOOP_MIN_COUNT. Instead
1360 of statically allocating a predefined number, loop
1361 devices can be requested on-demand with the
1362 /dev/loop-control interface.
1366 mce [X86-32] Machine Check Exception
1368 mce=option [X86-64] See Documentation/x86/x86_64/boot-options.txt
1370 md= [HW] RAID subsystems devices and level
1371 See Documentation/md.txt.
1374 Format: <first>,<last>
1375 Specifies range of consoles to be captured by the MDA.
1377 mem=nn[KMG] [KNL,BOOT] Force usage of a specific amount of memory
1378 Amount of memory to be used when the kernel is not able
1379 to see the whole system memory or for test.
1380 [X86-32] Use together with memmap= to avoid physical
1381 address space collisions. Without memmap= PCI devices
1382 could be placed at addresses belonging to unused RAM.
1384 mem=nopentium [BUGS=X86-32] Disable usage of 4MB pages for kernel
1388 [KNL,SH] Allow user to override the default size for
1389 per-device physically contiguous DMA buffers.
1391 memmap=exactmap [KNL,X86] Enable setting of an exact
1392 E820 memory map, as specified by the user.
1393 Such memmap=exactmap lines can be constructed based on
1394 BIOS output or other requirements. See the memmap=nn@ss
1397 memmap=nn[KMG]@ss[KMG]
1398 [KNL] Force usage of a specific region of memory
1399 Region of memory to be used, from ss to ss+nn.
1401 memmap=nn[KMG]#ss[KMG]
1402 [KNL,ACPI] Mark specific memory as ACPI data.
1403 Region of memory to be used, from ss to ss+nn.
1405 memmap=nn[KMG]$ss[KMG]
1406 [KNL,ACPI] Mark specific memory as reserved.
1407 Region of memory to be used, from ss to ss+nn.
1408 Example: Exclude memory from 0x18690000-0x1869ffff
1409 memmap=64K$0x18690000
1411 memmap=0x10000$0x18690000
1413 memory_corruption_check=0/1 [X86]
1414 Some BIOSes seem to corrupt the first 64k of
1415 memory when doing things like suspend/resume.
1416 Setting this option will scan the memory
1417 looking for corruption. Enabling this will
1418 both detect corruption and prevent the kernel
1419 from using the memory being corrupted.
1420 However, its intended as a diagnostic tool; if
1421 repeatable BIOS-originated corruption always
1422 affects the same memory, you can use memmap=
1423 to prevent the kernel from using that memory.
1425 memory_corruption_check_size=size [X86]
1426 By default it checks for corruption in the low
1427 64k, making this memory unavailable for normal
1428 use. Use this parameter to scan for
1429 corruption in more or less memory.
1431 memory_corruption_check_period=seconds [X86]
1432 By default it checks for corruption every 60
1433 seconds. Use this parameter to check at some
1434 other rate. 0 disables periodic checking.
1436 memtest= [KNL,X86] Enable memtest
1438 default : 0 <disable>
1439 Specifies the number of memtest passes to be
1440 performed. Each pass selects another test
1441 pattern from a given set of patterns. Memtest
1442 fills the memory with this pattern, validates
1443 memory contents and reserves bad memory
1444 regions that are detected.
1446 meye.*= [HW] Set MotionEye Camera parameters
1447 See Documentation/video4linux/meye.txt.
1449 mfgpt_irq= [IA-32] Specify the IRQ to use for the
1450 Multi-Function General Purpose Timers on AMD Geode
1453 mfgptfix [X86-32] Fix MFGPT timers on AMD Geode platforms when
1454 the BIOS has incorrectly applied a workaround. TinyBIOS
1455 version 0.98 is known to be affected, 0.99 fixes the
1456 problem by letting the user disable the workaround.
1460 min_addr=nn[KMG] [KNL,BOOT,ia64] All physical memory below this
1461 physical address is ignored.
1463 mini2440= [ARM,HW,KNL]
1464 Format:[0..2][b][c][t]
1466 MINI2440 configuration specification:
1467 0 - The attached screen is the 3.5" TFT
1468 1 - The attached screen is the 7" TFT
1469 2 - The VGA Shield is attached (1024x768)
1470 Leaving out the screen size parameter will not load
1471 the TFT driver, and the framebuffer will be left
1473 b - Enable backlight. The TFT backlight pin will be
1474 linked to the kernel VESA blanking code and a GPIO
1475 LED. This parameter is not necessary when using the
1477 c - Enable the s3c camera interface.
1478 t - Reserved for enabling touchscreen support. The
1479 touchscreen support is not enabled in the mainstream
1480 kernel as of 2.6.30, a preliminary port can be found
1481 in the "bleeding edge" mini2440 support kernel at
1482 http://repo.or.cz/w/linux-2.6/mini2440.git
1485 [KNL] When CONFIG_DEBUG_MEMORY_INIT is set, this
1486 parameter allows control of the logging verbosity for
1487 the additional memory initialisation checks. A value
1488 of 0 disables mminit logging and a level of 4 will
1489 log everything. Information is printed at KERN_DEBUG
1490 so loglevel=8 may also need to be specified.
1493 [MOUSE] Maximum time between finger touching and
1494 leaving touchpad surface for touch to be considered
1495 a tap and be reported as a left button click (for
1496 touchpads working in absolute mode only).
1498 mousedev.xres= [MOUSE] Horizontal screen resolution, used for devices
1499 reporting absolute coordinates, such as tablets
1500 mousedev.yres= [MOUSE] Vertical screen resolution, used for devices
1501 reporting absolute coordinates, such as tablets
1503 movablecore=nn[KMG] [KNL,X86,IA-64,PPC] This parameter
1504 is similar to kernelcore except it specifies the
1505 amount of memory used for migratable allocations.
1506 If both kernelcore and movablecore is specified,
1507 then kernelcore will be at *least* the specified
1508 value but may be more. If movablecore on its own
1509 is specified, the administrator must be careful
1510 that the amount of memory usable for all allocations
1513 MTD_Partition= [MTD]
1514 Format: <name>,<region-number>,<size>,<offset>
1516 MTD_Region= [MTD] Format:
1517 <name>,<region-number>[,<base>,<size>,<buswidth>,<altbuswidth>]
1520 See drivers/mtd/cmdlinepart.c.
1522 multitce=off [PPC] This parameter disables the use of the pSeries
1523 firmware feature for updating multiple TCE entries
1526 onenand.bdry= [HW,MTD] Flex-OneNAND Boundary Configuration
1528 Format: [die0_boundary][,die0_lock][,die1_boundary][,die1_lock]
1530 boundary - index of last SLC block on Flex-OneNAND.
1531 The remaining blocks are configured as MLC blocks.
1532 lock - Configure if Flex-OneNAND boundary should be locked.
1533 Once locked, the boundary cannot be changed.
1534 1 indicates lock status, 0 indicates unlock status.
1537 ARM/S3C2412 JIVE boot control
1539 See arch/arm/mach-s3c2412/mach-jive.c
1541 mtouchusb.raw_coordinates=
1542 [HW] Make the MicroTouch USB driver use raw coordinates
1543 ('y', default) or cooked coordinates ('n')
1545 mtrr_chunk_size=nn[KMG] [X86]
1546 used for mtrr cleanup. It is largest continuous chunk
1547 that could hold holes aka. UC entries.
1549 mtrr_gran_size=nn[KMG] [X86]
1550 Used for mtrr cleanup. It is granularity of mtrr block.
1552 Large value could prevent small alignment from
1555 mtrr_spare_reg_nr=n [X86]
1557 Range: 0,7 : spare reg number
1559 Used for mtrr cleanup. It is spare mtrr entries number.
1560 Set to 2 or more if your graphical card needs more.
1562 n2= [NET] SDL Inc. RISCom/N2 synchronous serial card
1564 netdev= [NET] Network devices parameters
1565 Format: <irq>,<io>,<mem_start>,<mem_end>,<name>
1566 Note that mem_start is often overloaded to mean
1567 something different and driver-specific.
1568 This usage is only documented in each driver source
1572 [NETFILTER] Enable connection tracking flow accounting
1573 0 to disable accounting
1574 1 to enable accounting
1577 nfsaddrs= [NFS] Deprecated. Use ip= instead.
1578 See Documentation/filesystems/nfs/nfsroot.txt.
1580 nfsroot= [NFS] nfs root filesystem for disk-less boxes.
1581 See Documentation/filesystems/nfs/nfsroot.txt.
1583 nfsrootdebug [NFS] enable nfsroot debugging messages.
1584 See Documentation/filesystems/nfs/nfsroot.txt.
1586 nfs.callback_tcpport=
1587 [NFS] set the TCP port on which the NFSv4 callback
1588 channel should listen.
1591 [NFS] sets the pathname to the program which is used
1592 to update the NFS client cache entries.
1594 nfs.cache_getent_timeout=
1595 [NFS] sets the timeout after which an attempt to
1596 update a cache entry is deemed to have failed.
1598 nfs.idmap_cache_timeout=
1599 [NFS] set the maximum lifetime for idmapper cache
1603 [NFS] enable 64-bit inode numbers.
1604 If zero, the NFS client will fake up a 32-bit inode
1605 number for the readdir() and stat() syscalls instead
1606 of returning the full 64-bit number.
1607 The default is to return 64-bit inode numbers.
1609 nfs.nfs4_disable_idmapping=
1610 [NFSv4] When set, this option disables the NFSv4
1611 idmapper on the client, but only if the mount
1612 is using the 'sec=sys' security flavour. This may
1613 make migration from legacy NFSv2/v3 systems easier
1614 provided that the server has the appropriate support.
1615 The default is to always enable NFSv4 idmapping.
1617 nmi_debug= [KNL,AVR32,SH] Specify one or more actions to take
1618 when a NMI is triggered.
1619 Format: [state][,regs][,debounce][,die]
1621 nmi_watchdog= [KNL,BUGS=X86] Debugging features for SMP kernels
1622 Format: [panic,][nopanic,][num]
1624 0 - turn nmi_watchdog off
1625 When panic is specified, panic when an NMI watchdog
1626 timeout occurs (or 'nopanic' to override the opposite
1628 This is useful when you use a panic=... timeout and
1629 need the box quickly up again.
1631 netpoll.carrier_timeout=
1632 [NET] Specifies amount of time (in seconds) that
1633 netpoll should wait for a carrier. By default netpoll
1636 no387 [BUGS=X86-32] Tells the kernel to use the 387 maths
1637 emulation library even if a 387 maths coprocessor
1641 [HW] Never suspend the console
1642 Disable suspending of consoles during suspend and
1643 hibernate operations. Once disabled, debugging
1644 messages can reach various consoles while the rest
1645 of the system is being put to sleep (ie, while
1646 debugging driver suspend/resume hooks). This may
1647 not work reliably with all consoles, but is known
1648 to work with serial and VGA consoles.
1650 noaliencache [MM, NUMA, SLAB] Disables the allocation of alien
1651 caches in the slab allocator. Saves per-node memory,
1652 but will impact performance.
1656 noapic [SMP,APIC] Tells the kernel to not make use of any
1657 IOAPICs that may be present in the system.
1659 noautogroup Disable scheduler automatic task group creation.
1661 nobats [PPC] Do not use BATs for mapping kernel lowmem
1662 on "Classic" PPC cores.
1666 noclflush [BUGS=X86] Don't use the CLFLUSH instruction
1668 nodelayacct [KNL] Disable per-task delay accounting
1670 nodisconnect [HW,SCSI,M68K] Disables SCSI disconnects.
1672 nodsp [SH] Disable hardware DSP at boot time.
1674 noefi [X86] Disable EFI runtime services support.
1679 On X86-32 available only on PAE configured kernels.
1680 noexec=on: enable non-executable mappings (default)
1681 noexec=off: disable non-executable mappings
1684 Disable SMEP (Supervisor Mode Execution Protection)
1685 even if it is supported by processor.
1688 This affects only 32-bit executables.
1689 noexec32=on: enable non-executable mappings (default)
1690 read doesn't imply executable mappings
1691 noexec32=off: disable non-executable mappings
1692 read implies executable mappings
1694 nofpu [SH] Disable hardware FPU at boot time.
1696 nofxsr [BUGS=X86-32] Disables x86 floating point extended
1697 register save and restore. The kernel will only save
1698 legacy floating-point registers on task switch.
1700 noxsave [BUGS=X86] Disables x86 extended register state save
1701 and restore using xsave. The kernel will fallback to
1702 enabling legacy floating-point and sse state.
1704 nohlt [BUGS=ARM,SH] Tells the kernel that the sleep(SH) or
1705 wfi(ARM) instruction doesn't work correctly and not to
1706 use it. This is also useful when using JTAG debugger.
1708 no-hlt [BUGS=X86-32] Tells the kernel that the hlt
1709 instruction doesn't work correctly and not to
1712 no_file_caps Tells the kernel not to honor file capabilities. The
1713 only way then for a file to be executed with privilege
1714 is to be setuid root or executed by root.
1716 nohalt [IA-64] Tells the kernel not to use the power saving
1717 function PAL_HALT_LIGHT when idle. This increases
1718 power-consumption. On the positive side, it reduces
1719 interrupt wake-up latency, which may improve performance
1720 in certain environments such as networked servers or
1723 nohz= [KNL] Boottime enable/disable dynamic ticks
1724 Valid arguments: on, off
1727 noiotrap [SH] Disables trapped I/O port accesses.
1729 noirqdebug [X86-32] Disables the code which attempts to detect and
1730 disable unhandled interrupt sources.
1732 no_timer_check [X86,APIC] Disables the code which tests for
1733 broken timer IRQ sources.
1735 noisapnp [ISAPNP] Disables ISA PnP code.
1737 noinitrd [RAM] Tells the kernel not to load any configured
1740 nointremap [X86-64, Intel-IOMMU] Do not enable interrupt
1742 [Deprecated - use intremap=off]
1746 nojitter [IA-64] Disables jitter checking for ITC timers.
1748 no-kvmclock [X86,KVM] Disable paravirtualized KVM clock driver
1750 no-kvmapf [X86,KVM] Disable paravirtualized asynchronous page
1753 no-steal-acc [X86,KVM] Disable paravirtualized steal time accounting.
1754 steal time is computed, but won't influence scheduler
1757 nolapic [X86-32,APIC] Do not enable or use the local APIC.
1759 nolapic_timer [X86-32,APIC] Do not use the local APIC timer.
1761 noltlbs [PPC] Do not use large page/tlb entries for kernel
1762 lowmem mapping on PPC40x.
1764 nomca [IA-64] Disable machine check abort handling
1766 nomce [X86-32] Machine Check Exception
1768 nomfgpt [X86-32] Disable Multi-Function General Purpose
1769 Timer usage (for AMD Geode machines).
1771 nopat [X86] Disable PAT (page attribute table extension of
1772 pagetables) support.
1774 norandmaps Don't use address space randomization. Equivalent to
1775 echo 0 > /proc/sys/kernel/randomize_va_space
1777 noreplace-paravirt [X86,IA-64,PV_OPS] Don't patch paravirt_ops
1779 noreplace-smp [X86-32,SMP] Don't replace SMP instructions
1780 with UP alternatives
1782 noresidual [PPC] Don't use residual data on PReP machines.
1784 noresume [SWSUSP] Disables resume and restores original swap
1787 no-scroll [VGA] Disables scrollback.
1788 This is required for the Braillex ib80-piezo Braille
1789 reader made by F.H. Papenmeier (Germany).
1793 nosep [BUGS=X86-32] Disables x86 SYSENTER/SYSEXIT support.
1795 nosmp [SMP] Tells an SMP kernel to act as a UP kernel,
1796 and disable the IO APIC. legacy for "maxcpus=0".
1798 nosoftlockup [KNL] Disable the soft-lockup detector.
1800 nosync [HW,M68K] Disables sync negotiation for all devices.
1802 notsc [BUGS=X86-32] Disable Time Stamp Counter
1804 nousb [USB] Disable the USB subsystem
1806 nowatchdog [KNL] Disable the lockup detector (NMI watchdog).
1810 nox2apic [X86-64,APIC] Do not enable x2APIC mode.
1812 nptcg= [IA-64] Override max number of concurrent global TLB
1813 purges which is reported from either PAL_VM_SUMMARY or
1816 nr_cpus= [SMP] Maximum number of processors that an SMP kernel
1817 could support. nr_cpus=n : n >= 1 limits the kernel to
1818 supporting 'n' processors. Later in runtime you can not
1819 use hotplug cpu feature to put more cpu back to online.
1820 just like you compile the kernel NR_CPUS=n
1822 nr_uarts= [SERIAL] maximum number of UARTs to be registered.
1824 numa_zonelist_order= [KNL, BOOT] Select zonelist order for NUMA.
1825 one of ['zone', 'node', 'default'] can be specified
1826 This can be set from sysctl after boot.
1827 See Documentation/sysctl/vm.txt for details.
1829 ohci1394_dma=early [HW] enable debugging via the ohci1394 driver.
1830 See Documentation/debugging-via-ohci1394.txt for more
1833 olpc_ec_timeout= [OLPC] ms delay when issuing EC commands
1834 Rather than timing out after 20 ms if an EC
1835 command is not properly ACKed, override the length
1836 of the timeout. We have interrupts disabled while
1837 waiting for the ACK, so if this is set too high
1838 interrupts *may* be lost!
1840 omap_mux= [OMAP] Override bootloader pin multiplexing.
1841 Format: <mux_mode0.mode_name=value>...
1842 For example, to override I2C bus2:
1843 omap_mux=i2c2_scl.i2c2_scl=0x100,i2c2_sda.i2c2_sda=0x100
1845 oprofile.timer= [HW]
1846 Use timer interrupt instead of performance counters
1848 oprofile.cpu_type= Force an oprofile cpu type
1849 This might be useful if you have an older oprofile
1850 userland or if you want common events.
1851 Format: { arch_perfmon }
1852 arch_perfmon: [X86] Force use of architectural
1853 perfmon on Intel CPUs instead of the
1854 CPU specific event set.
1856 oops=panic Always panic on oopses. Default is to just kill the
1857 process, but there is a small probability of
1858 deadlocking the machine.
1859 This will also cause panics on machine check exceptions.
1860 Useful together with panic=30 to trigger a reboot.
1863 See Documentation/sound/oss/oss-parameters.txt
1865 panic= [KNL] Kernel behaviour on panic: delay <timeout>
1866 timeout > 0: seconds before rebooting
1867 timeout = 0: wait forever
1868 timeout < 0: reboot immediately
1871 parkbd.port= [HW] Parallel port number the keyboard adapter is
1872 connected to, default is 0.
1874 parkbd.mode= [HW] Parallel port keyboard adapter mode of operation,
1875 0 for XT, 1 for AT (default is AT).
1878 parport= [HW,PPT] Specify parallel ports. 0 disables.
1879 Format: { 0 | auto | 0xBBB[,IRQ[,DMA]] }
1880 Use 'auto' to force the driver to use any
1881 IRQ/DMA settings detected (the default is to
1882 ignore detected IRQ/DMA settings because of
1883 possible conflicts). You can specify the base
1884 address, IRQ, and DMA settings; IRQ and DMA
1885 should be numbers, or 'auto' (for using detected
1886 settings on that particular port), or 'nofifo'
1887 (to avoid using a FIFO even if it is detected).
1888 Parallel ports are assigned in the order they
1889 are specified on the command line, starting
1892 parport_init_mode= [HW,PPT]
1893 Configure VIA parallel port to operate in
1894 a specific mode. This is necessary on Pegasos
1895 computer where firmware has no options for setting
1896 up parallel port mode and sets it to spp.
1897 Currently this function knows 686a and 8231 chips.
1898 Format: [spp|ps2|epp|ecp|ecpepp]
1901 Halt all CPUs after the first oops has been printed for
1902 the specified number of seconds. This is to be used if
1903 your oopses keep scrolling off the screen.
1908 See header of drivers/block/paride/pcd.c.
1909 See also Documentation/blockdev/paride.txt.
1911 pci=option[,option...] [PCI] various PCI subsystem options:
1912 earlydump [X86] dump PCI config space before the kernel
1914 off [X86] don't probe for the PCI bus
1915 bios [X86-32] force use of PCI BIOS, don't access
1916 the hardware directly. Use this if your machine
1917 has a non-standard PCI host bridge.
1918 nobios [X86-32] disallow use of PCI BIOS, only direct
1919 hardware access methods are allowed. Use this
1920 if you experience crashes upon bootup and you
1921 suspect they are caused by the BIOS.
1922 conf1 [X86] Force use of PCI Configuration
1924 conf2 [X86] Force use of PCI Configuration
1926 noaer [PCIE] If the PCIEAER kernel config parameter is
1927 enabled, this kernel boot option can be used to
1928 disable the use of PCIE advanced error reporting.
1929 nodomains [PCI] Disable support for multiple PCI
1930 root domains (aka PCI segments, in ACPI-speak).
1931 nommconf [X86] Disable use of MMCONFIG for PCI
1933 check_enable_amd_mmconf [X86] check for and enable
1934 properly configured MMIO access to PCI
1935 config space on AMD family 10h CPU
1936 nomsi [MSI] If the PCI_MSI kernel config parameter is
1937 enabled, this kernel boot option can be used to
1938 disable the use of MSI interrupts system-wide.
1939 noioapicquirk [APIC] Disable all boot interrupt quirks.
1940 Safety option to keep boot IRQs enabled. This
1941 should never be necessary.
1942 ioapicreroute [APIC] Enable rerouting of boot IRQs to the
1943 primary IO-APIC for bridges that cannot disable
1944 boot IRQs. This fixes a source of spurious IRQs
1945 when the system masks IRQs.
1946 noioapicreroute [APIC] Disable workaround that uses the
1947 boot IRQ equivalent of an IRQ that connects to
1948 a chipset where boot IRQs cannot be disabled.
1949 The opposite of ioapicreroute.
1950 biosirq [X86-32] Use PCI BIOS calls to get the interrupt
1951 routing table. These calls are known to be buggy
1952 on several machines and they hang the machine
1953 when used, but on other computers it's the only
1954 way to get the interrupt routing table. Try
1955 this option if the kernel is unable to allocate
1956 IRQs or discover secondary PCI buses on your
1958 rom [X86] Assign address space to expansion ROMs.
1959 Use with caution as certain devices share
1960 address decoders between ROMs and other
1962 norom [X86] Do not assign address space to
1963 expansion ROMs that do not already have
1964 BIOS assigned address ranges.
1965 nobar [X86] Do not assign address space to the
1966 BARs that weren't assigned by the BIOS.
1967 irqmask=0xMMMM [X86] Set a bit mask of IRQs allowed to be
1968 assigned automatically to PCI devices. You can
1969 make the kernel exclude IRQs of your ISA cards
1971 pirqaddr=0xAAAAA [X86] Specify the physical address
1972 of the PIRQ table (normally generated
1973 by the BIOS) if it is outside the
1974 F0000h-100000h range.
1975 lastbus=N [X86] Scan all buses thru bus #N. Can be
1976 useful if the kernel is unable to find your
1977 secondary buses and you want to tell it
1978 explicitly which ones they are.
1979 assign-busses [X86] Always assign all PCI bus
1980 numbers ourselves, overriding
1981 whatever the firmware may have done.
1982 usepirqmask [X86] Honor the possible IRQ mask stored
1983 in the BIOS $PIR table. This is needed on
1984 some systems with broken BIOSes, notably
1985 some HP Pavilion N5400 and Omnibook XE3
1986 notebooks. This will have no effect if ACPI
1987 IRQ routing is enabled.
1988 noacpi [X86] Do not use ACPI for IRQ routing
1989 or for PCI scanning.
1990 use_crs [X86] Use PCI host bridge window information
1991 from ACPI. On BIOSes from 2008 or later, this
1992 is enabled by default. If you need to use this,
1993 please report a bug.
1994 nocrs [X86] Ignore PCI host bridge windows from ACPI.
1995 If you need to use this, please report a bug.
1996 routeirq Do IRQ routing for all PCI devices.
1997 This is normally done in pci_enable_device(),
1998 so this option is a temporary workaround
1999 for broken drivers that don't call it.
2000 skip_isa_align [X86] do not align io start addr, so can
2001 handle more pci cards
2002 firmware [ARM] Do not re-enumerate the bus but instead
2003 just use the configuration from the
2004 bootloader. This is currently used on
2005 IXP2000 systems where the bus has to be
2006 configured a certain way for adjunct CPUs.
2007 noearly [X86] Don't do any early type 1 scanning.
2008 This might help on some broken boards which
2009 machine check when some devices' config space
2010 is read. But various workarounds are disabled
2011 and some IOMMU drivers will not work.
2012 bfsort Sort PCI devices into breadth-first order.
2013 This sorting is done to get a device
2014 order compatible with older (<= 2.4) kernels.
2015 nobfsort Don't sort PCI devices into breadth-first order.
2016 cbiosize=nn[KMG] The fixed amount of bus space which is
2017 reserved for the CardBus bridge's IO window.
2018 The default value is 256 bytes.
2019 cbmemsize=nn[KMG] The fixed amount of bus space which is
2020 reserved for the CardBus bridge's memory
2021 window. The default value is 64 megabytes.
2024 [<order of align>@][<domain>:]<bus>:<slot>.<func>[; ...]
2025 Specifies alignment and device to reassign
2026 aligned memory resources.
2027 If <order of align> is not specified,
2028 PAGE_SIZE is used as alignment.
2029 PCI-PCI bridge can be specified, if resource
2030 windows need to be expanded.
2031 ecrc= Enable/disable PCIe ECRC (transaction layer
2032 end-to-end CRC checking).
2033 bios: Use BIOS/firmware settings. This is the
2037 realloc reallocate PCI resources if allocations done by BIOS
2040 pcie_aspm= [PCIE] Forcibly enable or disable PCIe Active State Power
2043 force Enable ASPM even on devices that claim not to support it.
2044 WARNING: Forcing ASPM on may cause system lockups.
2046 pcie_ports= [PCIE] PCIe ports handling:
2047 auto Ask the BIOS whether or not to use native PCIe services
2048 associated with PCIe ports (PME, hot-plug, AER). Use
2049 them only if that is allowed by the BIOS.
2050 native Use native PCIe services associated with PCIe ports
2052 compat Treat PCIe ports as PCI-to-PCI bridges, disable the PCIe
2055 pcie_pme= [PCIE,PM] Native PCIe PME signaling options:
2056 nomsi Do not use MSI for native PCIe PME signaling (this makes
2057 all PCIe root ports use INTx for all services).
2059 pcmv= [HW,PCMCIA] BadgePAD 4
2062 See Documentation/blockdev/paride.txt.
2064 pdcchassis= [PARISC,HW] Disable/Enable PDC Chassis Status codes at
2067 See arch/parisc/kernel/pdc_chassis.c
2069 percpu_alloc= Select which percpu first chunk allocator to use.
2070 Currently supported values are "embed" and "page".
2071 Archs may support subset or none of the selections.
2072 See comments in mm/percpu.c for details on each
2073 allocator. This parameter is primarily for debugging
2074 and performance comparison.
2077 See Documentation/blockdev/paride.txt.
2080 See Documentation/blockdev/paride.txt.
2082 pirq= [SMP,APIC] Manual mp-table setup
2083 See Documentation/x86/i386/IO-APIC.txt.
2085 plip= [PPT,NET] Parallel port network link
2086 Format: { parport<nr> | timid | 0 }
2087 See also Documentation/parport.txt.
2089 pmtmr= [X86] Manual setup of pmtmr I/O Port.
2090 Override pmtimer IOPort with a hex value.
2094 Enable PNP debug messages (depends on the
2095 CONFIG_PNP_DEBUG_MESSAGES option). Change at run-time
2096 via /sys/module/pnp/parameters/debug. We always show
2097 current resource usage; turning this on also shows
2098 possible settings and some assignment information.
2104 { on | off | curr | res | no-curr | no-res }
2107 [ISAPNP] Exclude IRQs for the autoconfiguration
2110 [ISAPNP] Exclude DMAs for the autoconfiguration
2112 pnp_reserve_io= [ISAPNP] Exclude I/O ports for the autoconfiguration
2113 Ranges are in pairs (I/O port base and size).
2116 [ISAPNP] Exclude memory regions for the
2118 Ranges are in pairs (memory base and size).
2120 ports= [IP_VS_FTP] IPVS ftp helper module
2122 Up to 8 (IP_VS_APP_MAX_PORTS) ports
2124 Format: <port>,<port>....
2126 print-fatal-signals=
2127 [KNL] debug: print fatal signals
2129 If enabled, warn about various signal handling
2130 related application anomalies: too many signals,
2131 too many POSIX.1 timers, fatal signals causing a
2134 If you hit the warning due to signal overflow,
2135 you might want to try "ulimit -i unlimited".
2139 printk.time= Show timing data prefixed to each printk message line
2140 Format: <bool> (1/Y/y=enable, 0/N/n=disable)
2142 processor.max_cstate= [HW,ACPI]
2143 Limit processor to maximum C-state
2144 max_cstate=9 overrides any DMI blacklist limit.
2146 processor.nocst [HW,ACPI]
2147 Ignore the _CST method to determine C-states,
2148 instead using the legacy FADT method
2150 profile= [KNL] Enable kernel profiling via /proc/profile
2151 Format: [schedule,]<number>
2152 Param: "schedule" - profile schedule points.
2153 Param: <number> - step/bucket size as a power of 2 for
2154 statistical time based profiling.
2155 Param: "sleep" - profile D-state sleeping (millisecs).
2156 Requires CONFIG_SCHEDSTATS
2157 Param: "kvm" - profile VM exits.
2159 prompt_ramdisk= [RAM] List of RAM disks to prompt for floppy disk
2161 See Documentation/blockdev/ramdisk.txt.
2163 psmouse.proto= [HW,MOUSE] Highest PS2 mouse protocol extension to
2164 probe for; one of (bare|imps|exps|lifebook|any).
2165 psmouse.rate= [HW,MOUSE] Set desired mouse report rate, in reports
2167 psmouse.resetafter= [HW,MOUSE]
2168 Try to reset the device after so many bad packets
2171 [HW,MOUSE] Set desired mouse resolution, in dpi.
2172 psmouse.smartscroll=
2173 [HW,MOUSE] Controls Logitech smartscroll autorepeat.
2174 0 = disabled, 1 = enabled (default).
2176 pstore.backend= Specify the name of the pstore backend to use
2179 See Documentation/blockdev/paride.txt.
2182 [KNL] Number of legacy pty's. Overwrites compiled-in
2185 quiet [KNL] Disable most log messages
2190 See Documentation/md.txt.
2192 ramdisk_blocksize= [RAM]
2193 See Documentation/blockdev/ramdisk.txt.
2195 ramdisk_size= [RAM] Sizes of RAM disks in kilobytes
2196 See Documentation/blockdev/ramdisk.txt.
2198 rcupdate.blimit= [KNL,BOOT]
2199 Set maximum number of finished RCU callbacks to process
2202 rcupdate.qhimark= [KNL,BOOT]
2203 Set threshold of queued
2204 RCU callbacks over which batch limiting is disabled.
2206 rcupdate.qlowmark= [KNL,BOOT]
2207 Set threshold of queued RCU callbacks below which
2208 batch limiting is re-enabled.
2212 Run specified binary instead of /init from the ramdisk,
2213 used for early userspace startup. See initrd.
2215 reboot= [BUGS=X86-32,BUGS=ARM,BUGS=IA-64] Rebooting mode
2216 Format: <reboot_mode>[,<reboot_mode2>[,...]]
2217 See arch/*/kernel/reboot.c or arch/*/kernel/process.c
2220 [KNL, SMP] Set scheduler's default relax_domain_level.
2221 See Documentation/cgroups/cpusets.txt.
2223 reserve= [KNL,BUGS] Force the kernel to ignore some iomem area
2225 reservetop= [X86-32]
2227 Reserves a hole at the top of the kernel virtual
2232 Set the amount of memory to reserve for BIOS at
2233 the bottom of the address space.
2235 reset_devices [KNL] Force drivers to reset the underlying device
2236 during initialization.
2239 Specify the partition device for software suspend
2241 resume_offset= [SWSUSP]
2242 Specify the offset from the beginning of the partition
2243 given by "resume=" at which the swap header is located,
2244 in <PAGE_SIZE> units (needed only for swap files).
2245 See Documentation/power/swsusp-and-swap-files.txt
2247 hibernate= [HIBERNATION]
2248 noresume Don't check if there's a hibernation image
2249 present during boot.
2250 nocompress Don't compress/decompress hibernation images.
2252 retain_initrd [RAM] Keep initrd memory after extraction
2254 rhash_entries= [KNL,NET]
2255 Set number of hash buckets for route cache
2257 riscom8= [HW,SERIAL]
2258 Format: <io_board1>[,<io_board2>[,...<io_boardN>]]
2260 ro [KNL] Mount root device read-only on boot
2262 root= [KNL] Root filesystem
2263 See name_to_dev_t comment in init/do_mounts.c.
2265 rootdelay= [KNL] Delay (in seconds) to pause before attempting to
2266 mount the root filesystem
2268 rootflags= [KNL] Set root filesystem mount option string
2270 rootfstype= [KNL] Set root filesystem type
2272 rootwait [KNL] Wait (indefinitely) for root device to show up.
2273 Useful for devices that are detected asynchronously
2274 (e.g. USB and MMC devices).
2276 rw [KNL] Mount root device read-write on boot
2278 S [KNL] Run init in single mode
2281 See drivers/net/irda/sa1100_ir.c.
2283 sbni= [NET] Granch SBNI12 leased line adapter
2285 sched_debug [KNL] Enables verbose scheduler debug messages.
2287 security= [SECURITY] Choose a security module to enable at boot.
2288 If this boot parameter is not specified, only the first
2289 security module asking for security registration will be
2290 loaded. An invalid security module name will be treated
2291 as if no module has been chosen.
2293 selinux= [SELINUX] Disable or enable SELinux at boot time.
2294 Format: { "0" | "1" }
2295 See security/selinux/Kconfig help text.
2298 Default value is set via kernel config option.
2299 If enabled at boot time, /selinux/disable can be used
2300 later to disable prior to initial policy load.
2302 apparmor= [APPARMOR] Disable or enable AppArmor at boot time
2303 Format: { "0" | "1" }
2304 See security/apparmor/Kconfig help text
2307 Default value is set via kernel config option.
2309 serialnumber [BUGS=X86-32]
2312 Maximal number of shapers.
2314 show_msr= [x86] show boot-time MSR settings
2315 Format: { <integer> }
2316 Show boot-time (BIOS-initialized) MSR settings.
2317 The parameter means the number of CPUs to show,
2318 for example 1 means boot CPU only.
2325 slub_debug[=options[,slabs]] [MM, SLUB]
2326 Enabling slub_debug allows one to determine the
2327 culprit if slab objects become corrupted. Enabling
2328 slub_debug can create guard zones around objects and
2329 may poison objects when not in use. Also tracks the
2330 last alloc / free. For more information see
2331 Documentation/vm/slub.txt.
2333 slub_max_order= [MM, SLUB]
2334 Determines the maximum allowed order for slabs.
2335 A high setting may cause OOMs due to memory
2336 fragmentation. For more information see
2337 Documentation/vm/slub.txt.
2339 slub_min_objects= [MM, SLUB]
2340 The minimum number of objects per slab. SLUB will
2341 increase the slab order up to slub_max_order to
2342 generate a sufficiently large slab able to contain
2343 the number of objects indicated. The higher the number
2344 of objects the smaller the overhead of tracking slabs
2345 and the less frequently locks need to be acquired.
2346 For more information see Documentation/vm/slub.txt.
2348 slub_min_order= [MM, SLUB]
2349 Determines the mininum page order for slabs. Must be
2350 lower than slub_max_order.
2351 For more information see Documentation/vm/slub.txt.
2353 slub_nomerge [MM, SLUB]
2354 Disable merging of slabs with similar size. May be
2355 necessary if there is some reason to distinguish
2356 allocs to different slabs. Debug options disable
2357 merging on their own.
2358 For more information see Documentation/vm/slub.txt.
2361 Format: <io1>[,<io2>[,...,<io8>]]
2363 smp-alt-once [X86-32,SMP] On a hotplug CPU system, only
2364 attempt to substitute SMP alternatives once at boot.
2366 smsc-ircc2.nopnp [HW] Don't use PNP to discover SMC devices
2367 smsc-ircc2.ircc_cfg= [HW] Device configuration I/O port
2368 smsc-ircc2.ircc_sir= [HW] SIR base I/O port
2369 smsc-ircc2.ircc_fir= [HW] FIR base I/O port
2370 smsc-ircc2.ircc_irq= [HW] IRQ line
2371 smsc-ircc2.ircc_dma= [HW] DMA channel
2372 smsc-ircc2.ircc_transceiver= [HW] Transceiver type:
2373 0: Toshiba Satellite 1800 (GP data pin select)
2374 1: Fast pin select (default)
2378 [KNL] Should the soft-lockup detector generate panics.
2381 sonypi.*= [HW] Sony Programmable I/O Control Device driver
2382 See Documentation/sonypi.txt
2384 specialix= [HW,SERIAL] Specialix multi-serial port adapter
2385 See Documentation/serial/specialix.txt.
2387 spia_io_base= [HW,MTD]
2393 Enabled the stack tracer on boot up.
2397 Set the STI (builtin display/keyboard on the HP-PARISC
2398 machines) console (graphic card) which should be used
2399 as the initial boot-console.
2400 See also comment in drivers/video/console/sticore.c.
2403 See comment in drivers/video/console/sticore.c.
2406 Format: bpp:<bpp1>[:<bpp2>[:<bpp3>...]]
2408 sunrpc.min_resvport=
2409 sunrpc.max_resvport=
2411 SunRPC servers often require that client requests
2412 originate from a privileged port (i.e. a port in the
2413 range 0 < portnr < 1024).
2414 An administrator who wishes to reserve some of these
2415 ports for other uses may adjust the range that the
2416 kernel's sunrpc client considers to be privileged
2417 using these two parameters to set the minimum and
2418 maximum port values.
2422 Control how the NFS server code allocates CPUs to
2423 service thread pools. Depending on how many NICs
2424 you have and where their interrupts are bound, this
2425 option will affect which CPUs will do NFS serving.
2426 Note: this parameter cannot be changed while the
2427 NFS server is running.
2429 auto the server chooses an appropriate mode
2430 automatically using heuristics
2431 global a single global pool contains all CPUs
2432 percpu one pool for each CPU
2433 pernode one pool for each NUMA node (equivalent
2434 to global on non-NUMA machines)
2436 sunrpc.tcp_slot_table_entries=
2437 sunrpc.udp_slot_table_entries=
2439 Sets the upper limit on the number of simultaneous
2440 RPC calls that can be sent from the client to a
2441 server. Increasing these values may allow you to
2442 improve throughput, but will also increase the
2443 amount of memory reserved for use by the client.
2446 [KNL] Enable accounting of swap in memory resource
2447 controller if no parameter or 1 is given or disable
2448 it if 0 is given (See Documentation/cgroups/memory.txt)
2450 swiotlb= [IA-64] Number of I/O TLB slabs
2454 sysfs.deprecated=0|1 [KNL]
2455 Enable/disable old style sysfs layout for old udev
2456 on older distributions. When this option is enabled
2457 very new udev will not work anymore. When this option
2458 is disabled (or CONFIG_SYSFS_DEPRECATED not compiled)
2459 in older udev will not work anymore.
2460 Default depends on CONFIG_SYSFS_DEPRECATED_V2 set in
2461 the kernel configuration.
2463 sysrq_always_enabled
2465 Ignore sysrq setting - this boot parameter will
2466 neutralize any effect of /proc/sys/kernel/sysrq.
2467 Useful for debugging.
2471 test_suspend= [SUSPEND]
2472 Specify "mem" (for Suspend-to-RAM) or "standby" (for
2473 standby suspend) as the system sleep state to briefly
2474 enter during system startup. The system is woken from
2475 this state using a wakeup-capable RTC alarm.
2477 thash_entries= [KNL,NET]
2478 Set number of hash buckets for TCP connection
2480 thermal.act= [HW,ACPI]
2481 -1: disable all active trip points in all thermal zones
2482 <degrees C>: override all lowest active trip points
2484 thermal.crt= [HW,ACPI]
2485 -1: disable all critical trip points in all thermal zones
2486 <degrees C>: override all critical trip points
2488 thermal.nocrt= [HW,ACPI]
2489 Set to disable actions on ACPI thermal zone
2490 critical and hot trip points.
2492 thermal.off= [HW,ACPI]
2493 1: disable ACPI thermal control
2495 thermal.psv= [HW,ACPI]
2496 -1: disable all passive trip points
2497 <degrees C>: override all passive trip points to this
2500 thermal.tzp= [HW,ACPI]
2501 Specify global default ACPI thermal zone polling rate
2502 <deci-seconds>: poll all this frequency
2503 0: no polling (default)
2506 Force threading of all interrupt handlers except those
2507 marked explicitely IRQF_NO_THREAD.
2511 Specify if the kernel should make use of the cpu
2512 topology information if the hardware supports this.
2513 The scheduler will make use of this information and
2514 e.g. base its process migration decisions on it.
2519 tpm_suspend_pcr=[HW,TPM]
2520 Format: integer pcr id
2521 Specify that at suspend time, the tpm driver
2522 should extend the specified pcr with zeros,
2523 as a workaround for some chips which fail to
2524 flush the last written pcr on TPM_SaveState.
2525 This will guarantee that all the other pcrs
2528 trace_buf_size=nn[KMG]
2529 [FTRACE] will set tracing buffer size.
2531 trace_event=[event-list]
2532 [FTRACE] Set and start specified trace events in order
2533 to facilitate early boot debugging.
2534 See also Documentation/trace/events.txt
2536 tsc= Disable clocksource stability checks for TSC.
2538 [x86] reliable: mark tsc clocksource as reliable, this
2539 disables clocksource verification at runtime, as well
2540 as the stability checks done at bootup. Used to enable
2541 high-resolution timer mode on older hardware, and in
2542 virtualized environment.
2543 [x86] noirqtime: Do not use TSC to do irq accounting.
2544 Used to run time disable IRQ_TIME_ACCOUNTING on any
2545 platforms where RDTSC is slow and this accounting
2548 turbografx.map[2|3]= [HW,JOY]
2549 TurboGraFX parallel port interface
2551 <port#>,<js1>,<js2>,<js3>,<js4>,<js5>,<js6>,<js7>
2552 See also Documentation/input/joystick-parport.txt
2554 udbg-immortal [PPC] When debugging early kernel crashes that
2555 happen after console_init() and before a proper
2556 console driver takes over, this boot options might
2557 help "seeing" what's going on.
2559 uhash_entries= [KNL,NET]
2560 Set number of hash buckets for UDP/UDP-Lite connections
2563 [USB] Ignore overcurrent events (default N).
2564 Some badly-designed motherboards generate lots of
2565 bogus events, for ports that aren't wired to
2566 anything. Set this parameter to avoid log spamming.
2567 Note that genuine overcurrent events won't be
2571 [X86] Cause panic on unknown NMI.
2573 usbcore.authorized_default=
2574 [USB] Default USB device authorization:
2575 (default -1 = authorized except for wireless USB,
2576 0 = not authorized, 1 = authorized)
2578 usbcore.autosuspend=
2579 [USB] The autosuspend time delay (in seconds) used
2580 for newly-detected USB devices (default 2). This
2581 is the time required before an idle device will be
2582 autosuspended. Devices for which the delay is set
2583 to a negative value won't be autosuspended at all.
2585 usbcore.usbfs_snoop=
2586 [USB] Set to log all usbfs traffic (default 0 = off).
2588 usbcore.blinkenlights=
2589 [USB] Set to cycle leds on hubs (default 0 = off).
2591 usbcore.old_scheme_first=
2592 [USB] Start with the old device initialization
2593 scheme (default 0 = off).
2595 usbcore.use_both_schemes=
2596 [USB] Try the other device initialization scheme
2597 if the first one fails (default 1 = enabled).
2599 usbcore.initial_descriptor_timeout=
2600 [USB] Specifies timeout for the initial 64-byte
2601 USB_REQ_GET_DESCRIPTOR request in milliseconds
2602 (default 5000 = 5.0 seconds).
2605 [USBHID] The interval which mice are to be polled at.
2607 usb-storage.delay_use=
2608 [UMS] The delay in seconds before a new device is
2609 scanned for Logical Units (default 5).
2612 [UMS] A list of quirks entries to supplement or
2613 override the built-in unusual_devs list. List
2614 entries are separated by commas. Each entry has
2615 the form VID:PID:Flags where VID and PID are Vendor
2616 and Product ID values (4-digit hex numbers) and
2617 Flags is a set of characters, each corresponding
2618 to a common usb-storage quirk flag as follows:
2619 a = SANE_SENSE (collect more than 18 bytes
2621 b = BAD_SENSE (don't collect more than 18
2622 bytes of sense data);
2623 c = FIX_CAPACITY (decrease the reported
2624 device capacity by one sector);
2625 d = NO_READ_DISC_INFO (don't use
2626 READ_DISC_INFO command);
2627 e = NO_READ_CAPACITY_16 (don't use
2628 READ_CAPACITY_16 command);
2629 h = CAPACITY_HEURISTICS (decrease the
2630 reported device capacity by one
2631 sector if the number is odd);
2632 i = IGNORE_DEVICE (don't bind to this
2634 l = NOT_LOCKABLE (don't try to lock and
2635 unlock ejectable media);
2636 m = MAX_SECTORS_64 (don't transfer more
2637 than 64 sectors = 32 KB at a time);
2638 n = INITIAL_READ10 (force a retry of the
2639 initial READ(10) command);
2640 o = CAPACITY_OK (accept the capacity
2641 reported by the device);
2642 r = IGNORE_RESIDUE (the device reports
2643 bogus residue values);
2644 s = SINGLE_LUN (the device has only one
2646 w = NO_WP_DETECT (don't test whether the
2647 medium is write-protected).
2648 Example: quirks=0419:aaf5:rl,0421:0433:rc
2650 user_debug= [KNL,ARM]
2652 See arch/arm/Kconfig.debug help text.
2653 1 - undefined instruction events
2655 4 - invalid data aborts
2658 Example: user_debug=31
2661 [X86] Flags controlling user PTE allocations.
2663 nohigh = do not allocate PTE pages in
2664 HIGHMEM regardless of setting
2668 vdso=2: enable compat VDSO (default with COMPAT_VDSO)
2669 vdso=1: enable VDSO (default)
2670 vdso=0: disable VDSO mapping
2673 vdso32=2: enable compat VDSO (default with COMPAT_VDSO)
2674 vdso32=1: enable 32-bit VDSO (default)
2675 vdso32=0: disable 32-bit VDSO mapping
2678 vector=percpu: enable percpu vector domain
2680 video= [FB] Frame buffer configuration
2681 See Documentation/fb/modedb.txt.
2683 vga= [BOOT,X86-32] Select a particular video mode
2684 See Documentation/x86/boot.txt and
2685 Documentation/svga.txt.
2686 Use vga=ask for menu.
2687 This is actually a boot loader parameter; the value is
2688 passed to the kernel using a special protocol.
2690 vmalloc=nn[KMG] [KNL,BOOT] Forces the vmalloc area to have an exact
2691 size of <nn>. This can be used to increase the
2692 minimum size (128MB on x86). It can also be used to
2693 decrease the size and leave more room for directly
2696 vmhalt= [KNL,S390] Perform z/VM CP command after system halt.
2699 vmpanic= [KNL,S390] Perform z/VM CP command after kernel panic.
2702 vmpoff= [KNL,S390] Perform z/VM CP command after power off.
2706 Controls the behavior of vsyscalls (i.e. calls to
2707 fixed addresses of 0xffffffffff600x00 from legacy
2708 code). Most statically-linked binaries and older
2709 versions of glibc use these calls. Because these
2710 functions are at fixed addresses, they make nice
2711 targets for exploits that can control RIP.
2713 emulate [default] Vsyscalls turn into traps and are
2714 emulated reasonably safely.
2716 native Vsyscalls are native syscall instructions.
2717 This is a little bit faster than trapping
2718 and makes a few dynamic recompilers work
2719 better than they would in emulation mode.
2720 It also makes exploits much easier to write.
2722 none Vsyscalls don't work at all. This makes
2723 them quite hard to use for exploits but
2724 might break your system.
2726 vt.cur_default= [VT] Default cursor shape.
2727 Format: 0xCCBBAA, where AA, BB, and CC are the same as
2728 the parameters of the <Esc>[?A;B;Cc escape sequence;
2729 see VGA-softcursor.txt. Default: 2 = underline.
2731 vt.default_blu= [VT]
2732 Format: <blue0>,<blue1>,<blue2>,...,<blue15>
2733 Change the default blue palette of the console.
2734 This is a 16-member array composed of values
2737 vt.default_grn= [VT]
2738 Format: <green0>,<green1>,<green2>,...,<green15>
2739 Change the default green palette of the console.
2740 This is a 16-member array composed of values
2743 vt.default_red= [VT]
2744 Format: <red0>,<red1>,<red2>,...,<red15>
2745 Change the default red palette of the console.
2746 This is a 16-member array composed of values
2752 Set system-wide default UTF-8 mode for all tty's.
2753 Default is 1, i.e. UTF-8 mode is enabled for all
2754 newly opened terminals.
2756 vt.global_cursor_default=
2759 Set system-wide default for whether a cursor
2760 is shown on new VTs. Default is -1,
2761 i.e. cursors will be created by default unless
2762 overridden by individual drivers. 0 will hide
2763 cursors, 1 will display them.
2765 watchdog timers [HW,WDT] For information on watchdog timers,
2766 see Documentation/watchdog/watchdog-parameters.txt
2767 or other driver-specific files in the
2768 Documentation/watchdog/ directory.
2770 x2apic_phys [X86-64,APIC] Use x2apic physical mode instead of
2771 default x2apic cluster mode on platforms
2774 x86_mrst_timer= [X86-32,APBT]
2775 Choose timer option for x86 Moorestown MID platform.
2776 Two valid options are apbt timer only and lapic timer
2777 plus one apbt timer for broadcast timer.
2778 x86_mrst_timer=apbt_only | lapic_and_apbt
2780 xd= [HW,XT] Original XT pre-IDE (RLL encoded) disks.
2781 xd_geo= See header of drivers/block/xd.c.
2783 xen_emul_unplug= [HW,X86,XEN]
2784 Unplug Xen emulated devices
2785 Format: [unplug0,][unplug1]
2786 ide-disks -- unplug primary master IDE devices
2787 aux-ide-disks -- unplug non-primary-master IDE devices
2788 nics -- unplug network devices
2789 all -- unplug all emulated devices (NICs and IDE disks)
2790 unnecessary -- unplugging emulated devices is
2791 unnecessary even if the host did not respond to
2793 never -- do not unplug even if version check succeeds
2795 xirc2ps_cs= [NET,PCMCIA]
2797 <irq>,<irq_mask>,<io>,<full_duplex>,<do_sound>,<lockup_hack>[,<irq2>[,<irq3>[,<irq4>]]]
2799 ______________________________________________________________________
2803 Add more DRM drivers.
projects / linux-flexiantxendom0-3.2.10.git / blob