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 This document may not be entirely up to date and comprehensive. The command
21 "modinfo -p ${modulename}" shows a current list of all parameters of a loadable
22 module. Loadable modules, after being loaded into the running kernel, also
23 reveal their parameters in /sys/module/${modulename}/parameters/. Some of these
24 parameters may be changed at runtime by the command
25 "echo -n ${value} > /sys/module/${modulename}/parameters/${parm}".
27 The parameters listed below are only valid if certain kernel build options were
28 enabled and if respective hardware is present. The text in square brackets at
29 the beginning of each description states the restrictions within which a
30 parameter is applicable:
32 ACPI ACPI support is enabled.
33 ALSA ALSA sound support is enabled.
34 APIC APIC support is enabled.
35 APM Advanced Power Management support is enabled.
36 AX25 Appropriate AX.25 support is enabled.
37 CD Appropriate CD support is enabled.
38 DRM Direct Rendering Management support is enabled.
39 EDD BIOS Enhanced Disk Drive Services (EDD) is enabled
40 EFI EFI Partitioning (GPT) is enabled
41 EIDE EIDE/ATAPI support is enabled.
42 FB The frame buffer device is enabled.
43 HW Appropriate hardware is enabled.
44 IA-32 IA-32 aka i386 architecture is enabled.
45 IA-64 IA-64 architecture is enabled.
46 IOSCHED More than one I/O scheduler is enabled.
47 IP_PNP IP DHCP, BOOTP, or RARP is enabled.
48 ISAPNP ISA PnP code is enabled.
49 ISDN Appropriate ISDN support is enabled.
50 JOY Appropriate joystick support is enabled.
51 LIBATA Libata driver is enabled
52 LP Printer support is enabled.
53 LOOP Loopback device support is enabled.
54 M68k M68k architecture is enabled.
55 These options have more detailed description inside of
56 Documentation/m68k/kernel-options.txt.
57 MCA MCA bus support is enabled.
58 MDA MDA console support is enabled.
59 MOUSE Appropriate mouse support is enabled.
60 MSI Message Signaled Interrupts (PCI).
61 MTD MTD support is enabled.
62 NET Appropriate network support is enabled.
63 NUMA NUMA support is enabled.
64 GENERIC_TIME The generic timeofday code is enabled.
65 NFS Appropriate NFS support is enabled.
66 OSS OSS sound support is enabled.
67 PARIDE The ParIDE subsystem is enabled.
68 PARISC The PA-RISC architecture is enabled.
69 PCI PCI bus support is enabled.
70 PCMCIA The PCMCIA subsystem is enabled.
71 PNP Plug & Play support is enabled.
72 PPC PowerPC architecture is enabled.
73 PPT Parallel port support is enabled.
74 PS2 Appropriate PS/2 support is enabled.
75 RAM RAM disk support is enabled.
76 S390 S390 architecture is enabled.
77 SCSI Appropriate SCSI support is enabled.
78 A lot of drivers has their options described inside of
80 SELINUX SELinux support is enabled.
81 SERIAL Serial support is enabled.
82 SH SuperH architecture is enabled.
83 SMP The kernel is an SMP kernel.
84 SPARC Sparc architecture is enabled.
85 SWSUSP Software suspend is enabled.
86 TS Appropriate touchscreen support is enabled.
87 USB USB support is enabled.
88 USBHID USB Human Interface Device support is enabled.
89 V4L Video For Linux support is enabled.
90 VGA The VGA console has been enabled.
91 VT Virtual terminal support is enabled.
92 WDT Watchdog support is enabled.
93 XT IBM PC/XT MFM hard disk support is enabled.
94 X86-64 X86-64 architecture is enabled.
95 More X86-64 boot options can be found in
96 Documentation/x86_64/boot-options.txt .
98 In addition, the following text indicates that the option:
100 BUGS= Relates to possible processor bugs on the said processor.
101 KNL Is a kernel start-up parameter.
102 BOOT Is a boot loader parameter.
104 Parameters denoted with BOOT are actually interpreted by the boot
105 loader, and have no meaning to the kernel directly.
106 Do not modify the syntax of boot loader parameters without extreme
107 need or coordination with <Documentation/i386/boot.txt>.
109 There are also arch-specific kernel-parameters not documented here.
110 See for example <Documentation/x86_64/boot-options.txt>.
112 Note that ALL kernel parameters listed below are CASE SENSITIVE, and that
113 a trailing = on the name of any parameter states that that parameter will
114 be entered as an environment variable, whereas its absence indicates that
115 it will appear as a kernel argument readable via /proc/cmdline by programs
116 running once the system is up.
118 The number of kernel parameters is not limited, but the length of the
119 complete command line (parameters including spaces etc.) is limited to
120 a fixed number of characters. This limit depends on the architecture
121 and is between 256 and 4096 characters. It is defined in the file
122 ./include/asm/setup.h as COMMAND_LINE_SIZE.
125 53c7xx= [HW,SCSI] Amiga SCSI controllers
126 See header of drivers/scsi/53c7xx.c.
127 See also Documentation/scsi/ncr53c7xx.txt.
129 acpi= [HW,ACPI] Advanced Configuration and Power Interface
130 Format: { force | off | ht | strict | noirq }
131 force -- enable ACPI if default was off
132 off -- disable ACPI if default was on
133 noirq -- do not use ACPI for IRQ routing
134 ht -- run only enough ACPI to enable Hyper Threading
135 strict -- Be less tolerant of platforms that are not
136 strictly ACPI specification compliant.
138 See also Documentation/pm.txt, pci=noacpi
140 acpi_sleep= [HW,ACPI] Sleep options
141 Format: { s3_bios, s3_mode }
142 See Documentation/power/video.txt
144 acpi_sci= [HW,ACPI] ACPI System Control Interrupt trigger mode
145 Format: { level | edge | high | low }
147 acpi_irq_balance [HW,ACPI]
148 ACPI will balance active IRQs
151 acpi_irq_nobalance [HW,ACPI]
152 ACPI will not move active IRQs (default)
155 acpi_irq_pci= [HW,ACPI] If irq_balance, clear listed IRQs for
157 Format: <irq>,<irq>...
159 acpi_irq_isa= [HW,ACPI] If irq_balance, mark listed IRQs used by ISA
160 Format: <irq>,<irq>...
162 acpi_os_name= [HW,ACPI] Tell ACPI BIOS the name of the OS
163 Format: To spoof as Windows 98: ="Microsoft Windows"
165 acpi_osi= [HW,ACPI] empty param disables _OSI
167 acpi_serialize [HW,ACPI] force serialization of AML methods
169 acpi_skip_timer_override [HW,ACPI]
170 Recognize and ignore IRQ0/pin2 Interrupt Override.
171 For broken nForce2 BIOS resulting in XT-PIC timer.
172 acpi_use_timer_override [HW,ACPI}
173 Use timer override. For some broken Nvidia NF5 boards
174 that require a timer override, but don't have
177 acpi_dbg_layer= [HW,ACPI]
179 Each bit of the <int> indicates an ACPI debug layer,
180 1: enable, 0: disable. It is useful for boot time
181 debugging. After system has booted up, it can be set
182 via /proc/acpi/debug_layer.
184 acpi_dbg_level= [HW,ACPI]
186 Each bit of the <int> indicates an ACPI debug level,
187 1: enable, 0: disable. It is useful for boot time
188 debugging. After system has booted up, it can be set
189 via /proc/acpi/debug_level.
191 acpi_fake_ecdt [HW,ACPI] Workaround failure due to BIOS lacking ECDT
193 acpi_generic_hotkey [HW,ACPI]
194 Allow consolidated generic hotkey driver to
195 override platform specific driver.
196 See also Documentation/acpi-hotkey.txt.
198 acpi_pm_good [IA-32,X86-64]
199 Override the pmtimer bug detection: force the kernel
200 to assume that this machine's pmtimer latches its value
201 and always returns good values.
203 enable_timer_pin_1 [i386,x86-64]
204 Enable PIN 1 of APIC timer
205 Can be useful to work around chipset bugs
206 (in particular on some ATI chipsets).
207 The kernel tries to set a reasonable default.
209 disable_timer_pin_1 [i386,x86-64]
210 Disable PIN 1 of APIC timer
211 Can be useful to work around chipset bugs.
214 Format: <io>,<irq>,<dma>,<dma2>
215 See also Documentation/sound/oss/AD1816.
218 Format: <io>,<irq>,<dma>,<dma2>,<type>
224 See header of drivers/scsi/advansys.c.
226 advwdt= [HW,WDT] Advantech WDT
227 Format: <iostart>,<iostop>
229 aedsp16= [HW,OSS] Audio Excel DSP 16
230 Format: <io>,<irq>,<dma>,<mss_io>,<mpu_io>,<mpu_irq>
231 See also header of sound/oss/aedsp16.c.
234 See Documentation/scsi/aha152x.txt.
237 Format: <portbase>[,<buson>,<busoff>[,<dmaspeed>]]
240 See Documentation/scsi/aic7xxx.txt.
243 See Documentation/scsi/aic79xx.txt.
245 amijoy.map= [HW,JOY] Amiga joystick support
246 Map of devices attached to JOY0DAT and JOY1DAT
248 See also Documentation/kernel/input/joystick.txt
250 analog.map= [HW,JOY] Analog joystick and gamepad support
251 Specifies type or capabilities of an analog joystick
252 connected to one of 16 gameports
253 Format: <type1>,<type2>,..<type16>
256 Power management functions (SPARCstation-4/5 + deriv.)
258 Disable APC CPU standby support. SPARCstation-Fox does
259 not play well with APC CPU idle - disable it if you have
260 APC and your system crashes randomly.
262 apic= [APIC,i386] Change the output verbosity whilst booting
263 Format: { quiet (default) | verbose | debug }
264 Change the amount of debugging information output
265 when initialising the APIC and IO-APIC components.
267 apm= [APM] Advanced Power Management
268 See header of arch/i386/kernel/apm.c.
273 arcrimi= [HW,NET] ARCnet - "RIM I" (entirely mem-mapped) cards
274 Format: <io>,<irq>,<nodeID>
278 atarimouse= [HW,MOUSE] Atari Mouse
280 atascsi= [HW,SCSI] Atari SCSI
282 atkbd.extra= [HW] Enable extra LEDs and keys on IBM RapidAccess,
283 EzKey and similar keyboards
285 atkbd.reset= [HW] Reset keyboard during initialization
287 atkbd.set= [HW] Select keyboard code set
288 Format: <int> (2 = AT (default), 3 = PS/2)
290 atkbd.scroll= [HW] Enable scroll wheel on MS Office and similar
293 atkbd.softraw= [HW] Choose between synthetic and real raw mode
294 Format: <bool> (0 = real, 1 = synthetic (default))
296 atkbd.softrepeat= [HW]
297 Use software keyboard repeat
301 aztcd= [HW,CD] Aztech CD268 CDROM driver
302 Format: <io>,0x79 (?)
304 baycom_epp= [HW,AX25]
307 baycom_par= [HW,AX25] BayCom Parallel Port AX.25 Modem
309 See header of drivers/net/hamradio/baycom_par.c.
311 baycom_ser_fdx= [HW,AX25]
312 BayCom Serial Port AX.25 Modem (Full Duplex Mode)
313 Format: <io>,<irq>,<mode>[,<baud>]
314 See header of drivers/net/hamradio/baycom_ser_fdx.c.
316 baycom_ser_hdx= [HW,AX25]
317 BayCom Serial Port AX.25 Modem (Half Duplex Mode)
318 Format: <io>,<irq>,<mode>
319 See header of drivers/net/hamradio/baycom_ser_hdx.c.
321 blkmtd_device= [HW,MTD]
327 bttv.card= [HW,V4L] bttv (bt848 + bt878 based grabber cards)
328 bttv.radio= Most important insmod options are available as
330 bttv.pll= See Documentation/video4linux/bttv/Insmod-options
331 bttv.tuner= and Documentation/video4linux/bttv/CARDLIST
334 See drivers/scsi/BusLogic.c, comment before function
335 BusLogic_ParseDriverOptions().
337 c101= [NET] Moxa C101 synchronous serial card
339 cachesize= [BUGS=IA-32] Override level 2 CPU cache size detection.
340 Sometimes CPU hardware bugs make them report the cache
341 size incorrectly. The kernel will attempt work arounds
342 to fix known problems, but for some CPUs it is not
343 possible to determine what the correct size should be.
344 This option provides an override for these situations.
347 Format: <io>,<irq>[,PAS]
348 See header of drivers/cdrom/cdu31a.c.
350 chandev= [HW,NET] Generic channel device initialisation
352 checkreqprot [SELINUX] Set initial checkreqprot flag value.
353 Format: { "0" | "1" }
354 See security/selinux/Kconfig help text.
355 0 -- check protection applied by kernel (includes
356 any implied execute protection).
357 1 -- check protection requested by application.
358 Default value is set via a kernel config option.
359 Value can be changed at runtime via
360 /selinux/checkreqprot.
362 clock= [BUGS=IA-32, HW] gettimeofday clocksource override.
364 Forces specified clocksource (if available) to be used
365 when calculating gettimeofday(). If specified
366 clocksource is not available, it defaults to PIT.
367 Format: { pit | tsc | cyclone | pmtmr }
369 code_bytes [IA32] How many bytes of object code to print in an
376 [IA32/X86_64] Disable/Enable interrupt 0 timer routing
377 over the 8254 in addition to over the IO-APIC. The
378 kernel tries to set a sensible default.
380 hpet= [IA-32,HPET] option to disable HPET and use PIT.
384 Format: { auto | [<io>,][<irq>] }
386 com20020= [HW,NET] ARCnet - COM20020 chipset
388 <io>[,<irq>[,<nodeID>[,<backplane>[,<ckp>[,<timeout>]]]]]
390 com90io= [HW,NET] ARCnet - COM90xx chipset (IO-mapped buffers)
394 ARCnet - COM90xx chipset (memory-mapped buffers)
395 Format: <io>[,<irq>[,<memstart>]]
397 condev= [HW,S390] console device
400 console= [KNL] Output console device and options.
402 tty<n> Use the virtual console device <n>.
406 Use the specified serial port. The options are of
407 the form "bbbbpnf", where "bbbb" is the baud rate,
408 "p" is parity ("n", "o", or "e"), "n" is number of
409 bits, and "f" is flow control ("r" for RTS or
410 omit it). Default is "9600n8".
412 See Documentation/serial-console.txt for more
414 Documentation/networking/netconsole.txt for an
417 uart,io,<addr>[,options]
418 uart,mmio,<addr>[,options]
419 Start an early, polled-mode console on the 8250/16550
420 UART at the specified I/O port or MMIO address,
421 switching to the matching ttyS device later. The
422 options are the same as for ttyS, above.
424 cpcihp_generic= [HW,PCI] Generic port I/O CompactPCI driver
426 <first_slot>,<last_slot>,<port>,<enum_bit>[,<debug>]
429 Format: { parport<nr> | auto | none }
431 crashkernel=nn[KMG]@ss[KMG]
432 [KNL] Reserve a chunk of physical memory to
433 hold a kernel to switch to with kexec on panic.
436 Format: <io>,<irq>,<dma>,<dma2>,<mpuio>,<mpuirq>
441 cs89x0_media= [HW,NET]
442 Format: { rj45 | aui | bnc }
444 cyclades= [HW,SERIAL] Cyclades multi-serial port adapter.
447 See header of drivers/s390/block/dasd_devmap.c.
449 db9.dev[2|3]= [HW,JOY] Multisystem joystick support via parallel port
450 (one device per port)
451 Format: <port#>,<type>
452 See also Documentation/input/joystick-parport.txt
454 debug [KNL] Enable kernel debugging (events log level).
457 [KNL] verbose self-tests
459 Print debugging info while doing the locking API
461 We default to 0 (no extra messages), setting it to
462 1 will print _a lot_ more information - normally
463 only useful to kernel developers.
466 Format: <area>[,<node>]
467 See also Documentation/networking/decnet.txt.
470 Set number of hash buckets for dentry cache.
473 IO parameters + enable/disable command.
475 digiepca= [HW,SERIAL]
476 See drivers/char/README.epca and
477 Documentation/digiepca.txt.
479 dmascc= [HW,AX25,SERIAL] AX.25 Z80SCC driver with DMA
481 Format: <io_dev0>[,<io_dev1>[,..<io_dev32>]]
483 dmasound= [HW,OSS] Sound subsystem buffers
489 earlyprintk= [IA-32,X86-64,SH]
491 earlyprintk=serial[,ttySn[,baudrate]]
493 Append ",keep" to not disable it when the real console
496 Only vga or serial at a time, not both.
498 Currently only ttyS0 and ttyS1 are supported.
500 Interaction with the standard serial driver is not
503 The VGA output is eventually overwritten by the real
508 ec_intr= [HW,ACPI] ACPI Embedded Controller interrupt mode
511 non-0: interrupt mode (default)
518 Format: {"of[f]" | "sk[ipmbr]"}
519 See comment in arch/i386/boot/edd.S
522 Format: <id>,<membase>,<irq>
524 eisa_irq_edge= [PARISC,HW]
525 See header of drivers/parisc/eisa.c.
528 See comment before function elanfreq_setup() in
529 arch/i386/kernel/cpu/cpufreq/elanfreq.c.
532 Format: {"anticipatory" | "cfq" | "deadline" | "noop"}
533 See Documentation/block/as-iosched.txt and
534 Documentation/block/deadline-iosched.txt for details.
536 elfcorehdr= [IA-32, X86_64]
537 Specifies physical address of start of kernel core
538 image elf header. Generally kexec loader will
539 pass this option to capture kernel.
540 See Documentation/kdump/kdump.txt for details.
542 enforcing [SELINUX] Set initial enforcing status.
544 See security/selinux/Kconfig help text.
545 0 -- permissive (log only, no denials).
546 1 -- enforcing (deny and log).
548 Value can be changed at runtime via /selinux/enforce.
551 Format: <spdif>,[<nomix>,[<amplifier>]]
552 See also header of sound/oss/es1371.c.
554 ether= [HW,NET] Ethernet cards parameters
555 This option is obsoleted by the "netdev=" option, which
556 has equivalent usage. See its documentation for details.
558 eurwdt= [HW,WDT] Eurotech CPU-1220/1410 onboard watchdog.
563 fail_make_request=[KNL]
564 General fault injection mechanism.
565 Format: <interval>,<probability>,<space>,<times>
566 See also /Documentation/fault-injection/.
569 See header of drivers/scsi/fd_mcs.c.
572 See header of drivers/scsi/fdomain.c.
575 See Documentation/floppy.txt.
578 [HW,JOY] Multisystem joystick and NES/SNES/PSX pad
579 support via parallel port (up to 5 devices per port)
580 Format: <port#>,<pad1>,<pad2>,<pad3>,<pad4>,<pad5>
581 See also Documentation/input/joystick-parport.txt
586 See header of drivers/scsi/gdth.c.
588 gpt [EFI] Forces disk with valid GPT signature but
589 invalid Protective MBR to be treated as GPT.
596 hashdist= [KNL,NUMA] Large hashes allocated during boot
597 are distributed across NUMA nodes. Defaults on
598 for IA-64, off otherwise.
599 Format: 0 | 1 (for off | on)
601 hcl= [IA-64] SGI's Hardware Graph compatibility layer
603 hd= [EIDE] (E)IDE hard drive subsystem geometry
604 Format: <cyl>,<head>,<sect>
606 hd?= [HW] (E)IDE subsystem
607 hd?lun= See Documentation/ide.txt.
609 highmem=nn[KMG] [KNL,BOOT] forces the highmem zone to have an exact
610 size of <nn>. This works even on boxes that have no
611 highmem otherwise. This also works to reduce highmem
612 size on bigger boxes.
614 highres= [KNL] Enable/disable high resolution timer mode.
615 Valid parameters: "on", "off"
619 See Documentation/isdn/README.HiSax.
621 hugepages= [HW,IA-32,IA-64] Maximal number of HugeTLB pages.
623 i8042.direct [HW] Put keyboard port into non-translated mode
624 i8042.dumbkbd [HW] Pretend that controller can only read data from
625 keyboard and cannot control its state
626 (Don't attempt to blink the leds)
627 i8042.noaux [HW] Don't check for auxiliary (== mouse) port
628 i8042.nokbd [HW] Don't check/create keyboard port
629 i8042.nomux [HW] Don't check presence of an active multiplexing
631 i8042.nopnp [HW] Don't use ACPIPnP / PnPBIOS to discover KBD/AUX
634 [HW] Frequency with which keyboard LEDs should blink
635 when kernel panics (default is 0.5 sec)
636 i8042.reset [HW] Reset the controller during init and cleanup
637 i8042.unlock [HW] Unlock (ignore) the keylock
641 i8k.ignore_dmi [HW] Continue probing hardware even if DMI data
642 indicates that the driver is running on unsupported
644 i8k.force [HW] Activate i8k driver even if SMM BIOS signature
645 does not match list of supported models.
647 [HW] Report power status in /proc/i8k
648 (disabled by default)
649 i8k.restricted [HW] Allow controlling fans only if SYS_ADMIN
652 ibmmcascsi= [HW,MCA,SCSI] IBM MicroChannel SCSI adapter
653 See Documentation/mca.txt.
656 Format: <io>[,<membase>[,<icn_id>[,<icn_id2>]]]
658 ide= [HW] (E)IDE subsystem
659 Format: ide=nodma or ide=doubler or ide=reverse
660 See Documentation/ide.txt.
662 ide?= [HW] (E)IDE subsystem
663 Format: ide?=noprobe or chipset specific parameters.
664 See Documentation/ide.txt.
666 idebus= [HW] (E)IDE subsystem - VLB/PCI bus speed
667 See Documentation/ide.txt.
670 Format: idle=poll or idle=halt
672 ignore_loglevel [KNL]
673 Ignore loglevel setting - this will print /all/
674 kernel messages to the console. Useful for debugging.
677 Set number of hash buckets for inode cache.
680 See header of drivers/scsi/in2000.c.
684 Run specified binary instead of /sbin/init as init
687 initcall_debug [KNL] Trace initcalls as they are executed. Useful
688 for working out where the kernel is dying during
691 initrd= [BOOT] Specify the location of the initial ramdisk
693 inport.irq= [HW] Inport (ATI XL and Microsoft) busmouse driver
696 combined_mode= [HW] control which driver uses IDE ports in combined
697 mode: legacy IDE driver, libata, or both
698 (in the libata case, libata.atapi_enabled=1 may be
699 useful as well). Note that using the ide or libata
700 options may affect your device naming (e.g. by
701 changing hdc to sdb).
702 Format: combined (default), ide, or libata
706 io7= [HW] IO7 for Marvel based alpha systems
707 See comment before marvel_specify_io7 in
708 arch/alpha/kernel/core_marvel.c.
711 See Documentation/nfsroot.txt.
713 ip2= [HW] Set IO/IRQ pairs for up to 4 IntelliPort boards
714 See comment before ip2_setup() in drivers/char/ip2.c.
716 ips= [HW,SCSI] Adaptec / IBM ServeRAID controller
717 See header of drivers/scsi/ips.c.
719 ports= [IP_VS_FTP] IPVS ftp helper module
721 Up to 8 (IP_VS_APP_MAX_PORTS) ports
723 Format: <port>,<port>....
726 When an interrupt is not handled search all handlers
727 for it. Intended to get systems with badly broken
731 When an interrupt is not handled search all handlers
732 for it. Also check all handlers each timer
733 interrupt. Intended to get systems with badly broken
737 Format: <RDP>,<reset>,<pci_scan>,<verbosity>
739 isolcpus= [KNL,SMP] Isolate CPUs from the general scheduler.
741 <cpu number>,...,<cpu number>
743 <cpu number>-<cpu number> (must be a positive range in ascending order)
745 <cpu number>,...,<cpu number>-<cpu number>
746 This option can be used to specify one or more CPUs
747 to isolate from the general SMP balancing and scheduling
748 algorithms. The only way to move a process onto or off
749 an "isolated" CPU is via the CPU affinity syscalls.
750 <cpu number> begins at 0 and the maximum value is
751 "number of CPUs in system - 1".
753 This option is the preferred way to isolate CPUs. The
754 alternative -- manually setting the CPU mask of all
755 tasks in the system -- can cause problems and
756 suboptimal load balancer performance.
759 Format: <io>,<irq>,<dma>,<setup>
763 js= [HW,JOY] Analog joystick
764 See Documentation/input/joystick.txt.
768 kstack=N [IA-32,X86-64] Print N words from the kernel stack
773 lapic [IA-32,APIC] Enable the local APIC even if BIOS
776 lasi= [HW,SCSI] PARISC LASI driver for the 53c700 chip
777 Format: addr:<io>,irq:<irq>
779 llsc*= [IA64] See function print_params() in
780 arch/ia64/sn/kernel/llsc4.c.
782 load_ramdisk= [RAM] List of ramdisks to load from floppy
783 See Documentation/ramdisk.txt.
785 lockd.nlm_grace_period=P [NFS] Assign grace period.
788 lockd.nlm_tcpport=N [NFS] Assign TCP port.
791 lockd.nlm_timeout=T [NFS] Assign timeout value.
794 lockd.nlm_udpport=M [NFS] Assign UDP port.
797 logibm.irq= [HW,MOUSE] Logitech Bus Mouse Driver
800 loglevel= All Kernel Messages with a loglevel smaller than the
801 console loglevel will be printed to the console. It can
802 also be changed with klogd or other programs. The
803 loglevels are defined as follows:
805 0 (KERN_EMERG) system is unusable
806 1 (KERN_ALERT) action must be taken immediately
807 2 (KERN_CRIT) critical conditions
808 3 (KERN_ERR) error conditions
809 4 (KERN_WARNING) warning conditions
810 5 (KERN_NOTICE) normal but significant condition
811 6 (KERN_INFO) informational
812 7 (KERN_DEBUG) debug-level messages
814 log_buf_len=n Sets the size of the printk ring buffer, in bytes.
815 Format: { n | nk | nM }
816 n must be a power of two. The default size
817 is set in the kernel config file.
819 lp=0 [LP] Specify parallel ports to use, e.g,
820 lp=port[,port...] lp=none,parport0 (lp0 not configured, lp1 uses
821 lp=reset first parallel port). 'lp=0' disables the
822 lp=auto printer driver. 'lp=reset' (which can be
823 specified in addition to the ports) causes
824 attached printers to be reset. Using
825 lp=port1,port2,... specifies the parallel ports
826 to associate lp devices with, starting with
827 lp0. A port specification may be 'none' to skip
828 that lp device, or a parport name such as
829 'parport0'. Specifying 'lp=auto' instead of a
830 port specification list means that device IDs
831 from each port should be examined, to see if
832 an IEEE 1284-compliant printer is attached; if
833 so, the driver will manage that printer.
834 See also header of drivers/char/lp.c.
837 Sets loops_per_jiffy to given constant, thus avoiding
838 time-consuming boot-time autodetection (up to 250 ms per
839 CPU). 0 enables autodetection (default). To determine
840 the correct value for your kernel, boot with normal
841 autodetection and see what value is printed. Note that
842 on SMP systems the preset will be applied to all CPUs,
843 which is likely to cause problems if your CPUs need
844 significantly divergent settings. An incorrect value
845 will cause delays in the kernel to be wrong, leading to
846 unpredictable I/O errors and other breakage. Although
847 unlikely, in the extreme case this might damage your
851 Format: <io>,<irq>,<dma>
853 mac5380= [HW,SCSI] Format:
854 <can_queue>,<cmd_per_lun>,<sg_tablesize>,<hostid>,<use_tags>
856 mac53c9x= [HW,SCSI] Format:
857 <num_esps>,<disconnect>,<nosync>,<can_queue>,<cmd_per_lun>,<sg_tablesize>,<hostid>,<use_tags>
859 machvec= [IA64] Force the use of a particular machine-vector
860 (machvec) in a generic kernel.
861 Example: machvec=hpzx1_swiotlb
863 max_loop= [LOOP] Maximum number of loopback devices that can
867 maxcpus= [SMP] Maximum number of processors that an SMP kernel
869 Using "nosmp" or "maxcpus=0" will disable SMP
870 entirely (the MPS table probe still happens, though).
871 A command-line option of "maxcpus=<NUM>", where <NUM>
872 is an integer greater than 0, limits the maximum number
873 of CPUs activated in SMP mode to <NUM>.
874 Using "maxcpus=1" on an SMP kernel is the trivial
875 case of an SMP kernel with only one CPU.
877 max_addr=[KMG] [KNL,BOOT,ia64] All physical memory greater than or
878 equal to this physical address is ignored.
880 max_luns= [SCSI] Maximum number of LUNs to probe.
881 Should be between 1 and 2^32-1.
884 [SCSI] Maximum number of LUNs received.
885 Should be between 1 and 16384.
887 mca-pentium [BUGS=IA-32]
892 Format: <port>,<irq>,<mitsumi_bug_93_wait>
896 mce [IA-32] Machine Check Exception
898 md= [HW] RAID subsystems devices and level
899 See Documentation/md.txt.
902 Format: <first>,<last>
903 Specifies range of consoles to be captured by the MDA.
905 mem=nn[KMG] [KNL,BOOT] Force usage of a specific amount of memory
906 Amount of memory to be used when the kernel is not able
907 to see the whole system memory or for test.
908 [IA-32] Use together with memmap= to avoid physical
909 address space collisions. Without memmap= PCI devices
910 could be placed at addresses belonging to unused RAM.
912 mem=nopentium [BUGS=IA-32] Disable usage of 4MB pages for kernel
915 memmap=exactmap [KNL,IA-32,X86_64] Enable setting of an exact
916 E820 memory map, as specified by the user.
917 Such memmap=exactmap lines can be constructed based on
918 BIOS output or other requirements. See the memmap=nn@ss
921 memmap=nn[KMG]@ss[KMG]
922 [KNL] Force usage of a specific region of memory
923 Region of memory to be used, from ss to ss+nn.
925 memmap=nn[KMG]#ss[KMG]
926 [KNL,ACPI] Mark specific memory as ACPI data.
927 Region of memory to be used, from ss to ss+nn.
929 memmap=nn[KMG]$ss[KMG]
930 [KNL,ACPI] Mark specific memory as reserved.
931 Region of memory to be used, from ss to ss+nn.
933 meye.*= [HW] Set MotionEye Camera parameters
934 See Documentation/video4linux/meye.txt.
939 [KNL,SMP] debug: override scheduler migration costs
940 Format: <level-1-usecs>,<level-2-usecs>,...
941 This debugging option can be used to override the
942 default scheduler migration cost matrix. The numbers
943 are indexed by 'CPU domain distance'.
944 E.g. migration_cost=1000,2000,3000 on an SMT NUMA
945 box will set up an intra-core migration cost of
946 1 msec, an inter-core migration cost of 2 msecs,
947 and an inter-node migration cost of 3 msecs.
949 WARNING: using the wrong values here can break
950 scheduler performance, so it's only for scheduler
951 development purposes, not production environments.
954 [KNL,SMP] migration cost auto-detect verbosity
956 If a system's migration matrix reported at bootup
957 seems erroneous then this option can be used to
958 increase verbosity of the detection process.
959 We default to 0 (no extra messages), 1 will print
960 some more information, and 2 will be really
961 verbose (probably only useful if you also have a
962 serial console attached to the system).
965 [KNL,SMP] multiply/divide migration costs by a factor
967 This debug option can be used to proportionally
968 increase or decrease the auto-detected migration
969 costs for all entries of the migration matrix.
970 E.g. migration_factor=150 will increase migration
971 costs by 50%. (and thus the scheduler will be less
972 eager migrating cache-hot tasks)
973 migration_factor=80 will decrease migration costs
974 by 20%. (thus the scheduler will be more eager to
977 WARNING: using the wrong values here can break
978 scheduler performance, so it's only for scheduler
979 development purposes, not production environments.
982 [MOUSE] Maximum time between finger touching and
983 leaving touchpad surface for touch to be considered
984 a tap and be reported as a left button click (for
985 touchpads working in absolute mode only).
987 mousedev.xres= [MOUSE] Horizontal screen resolution, used for devices
988 reporting absolute coordinates, such as tablets
989 mousedev.yres= [MOUSE] Vertical screen resolution, used for devices
990 reporting absolute coordinates, such as tablets
996 Format: <name>,<region-number>,<size>,<offset>
998 MTD_Region= [MTD] Format:
999 <name>,<region-number>[,<base>,<size>,<buswidth>,<altbuswidth>]
1002 See drivers/mtd/cmdline.c.
1004 mtouchusb.raw_coordinates=
1005 [HW] Make the MicroTouch USB driver use raw coordinates
1006 ('y', default) or cooked coordinates ('n')
1008 n2= [NET] SDL Inc. RISCom/N2 synchronous serial card
1011 See header of drivers/scsi/NCR_D700.c.
1015 ncr53c400= [HW,SCSI]
1017 ncr53c400a= [HW,SCSI]
1019 ncr53c406a= [HW,SCSI]
1021 ncr53c8xx= [HW,SCSI]
1023 netdev= [NET] Network devices parameters
1024 Format: <irq>,<io>,<mem_start>,<mem_end>,<name>
1025 Note that mem_start is often overloaded to mean
1026 something different and driver-specific.
1027 This usage is only documented in each driver source
1031 See Documentation/nfsroot.txt.
1033 nfsroot= [NFS] nfs root filesystem for disk-less boxes.
1034 See Documentation/nfsroot.txt.
1036 nfs.callback_tcpport=
1037 [NFS] set the TCP port on which the NFSv4 callback
1038 channel should listen.
1040 nfs.idmap_cache_timeout=
1041 [NFS] set the maximum lifetime for idmapper cache
1044 nmi_watchdog= [KNL,BUGS=IA-32] Debugging features for SMP kernels
1046 no387 [BUGS=IA-32] Tells the kernel to use the 387 maths
1047 emulation library even if a 387 maths coprocessor
1050 noacpi [LIBATA] Disables use of ACPI in libata suspend/resume
1054 noaliencache [MM, NUMA] Disables the allcoation of alien caches in
1055 the slab allocator. Saves per-node memory, but will
1056 impact performance on real NUMA hardware.
1060 noapic [SMP,APIC] Tells the kernel to not make use of any
1061 IOAPICs that may be present in the system.
1063 noasync [HW,M68K] Disables async and sync negotiation for
1066 nobats [PPC] Do not use BATs for mapping kernel lowmem
1067 on "Classic" PPC cores.
1071 nodelayacct [KNL] Disable per-task delay accounting
1073 nodisconnect [HW,SCSI,M68K] Disables SCSI disconnects.
1077 noexec [IA-32,X86-64]
1078 noexec=on: enable non-executable mappings (default)
1079 noexec=off: disable nn-executable mappings
1081 nofxsr [BUGS=IA-32] Disables x86 floating point extended
1082 register save and restore. The kernel will only save
1083 legacy floating-point registers on task switch.
1087 no-hlt [BUGS=IA-32] Tells the kernel that the hlt
1088 instruction doesn't work correctly and not to
1091 nohalt [IA-64] Tells the kernel not to use the power saving
1092 function PAL_HALT_LIGHT when idle. This increases
1093 power-consumption. On the positive side, it reduces
1094 interrupt wake-up latency, which may improve performance
1095 in certain environments such as networked servers or
1098 nohz= [KNL] Boottime enable/disable dynamic ticks
1099 Valid arguments: on, off
1102 noirqbalance [IA-32,SMP,KNL] Disable kernel irq balancing
1104 noirqdebug [IA-32] Disables the code which attempts to detect and
1105 disable unhandled interrupt sources.
1107 no_timer_check [IA-32,X86_64,APIC] Disables the code which tests for
1108 broken timer IRQ sources.
1110 noisapnp [ISAPNP] Disables ISA PnP code.
1112 noinitrd [RAM] Tells the kernel not to load any configured
1117 nolapic [IA-32,APIC] Do not enable or use the local APIC.
1119 noltlbs [PPC] Do not use large page/tlb entries for kernel
1120 lowmem mapping on PPC40x.
1122 nomca [IA-64] Disable machine check abort handling
1124 nomce [IA-32] Machine Check Exception
1126 noresidual [PPC] Don't use residual data on PReP machines.
1128 noresume [SWSUSP] Disables resume and restores original swap
1131 no-scroll [VGA] Disables scrollback.
1132 This is required for the Braillex ib80-piezo Braille
1133 reader made by F.H. Papenmeier (Germany).
1137 nosep [BUGS=IA-32] Disables x86 SYSENTER/SYSEXIT support.
1139 nosmp [SMP] Tells an SMP kernel to act as a UP kernel.
1141 nosync [HW,M68K] Disables sync negotiation for all devices.
1143 notsc [BUGS=IA-32] Disable Time Stamp Counter
1145 nousb [USB] Disable the USB subsystem
1149 nr_uarts= [SERIAL] maximum number of UARTs to be registered.
1154 opl3sa2= [HW,OSS] Format:
1155 <io>,<irq>,<dma>,<dma2>,<mss_io>,<mpu_io>,<ymode>,<loopback>[,<isapnp>,<multiple]
1157 oprofile.timer= [HW]
1158 Use timer interrupt instead of performance counters
1163 osst= [HW,SCSI] SCSI Tape Driver
1164 Format: <buffer_size>,<write_threshold>
1165 See also Documentation/scsi/st.txt.
1167 panic= [KNL] Kernel behaviour on panic
1170 parkbd.port= [HW] Parallel port number the keyboard adapter is
1171 connected to, default is 0.
1173 parkbd.mode= [HW] Parallel port keyboard adapter mode of operation,
1174 0 for XT, 1 for AT (default is AT).
1177 parport= [HW,PPT] Specify parallel ports. 0 disables.
1178 Format: { 0 | auto | 0xBBB[,IRQ[,DMA]] }
1179 Use 'auto' to force the driver to use any
1180 IRQ/DMA settings detected (the default is to
1181 ignore detected IRQ/DMA settings because of
1182 possible conflicts). You can specify the base
1183 address, IRQ, and DMA settings; IRQ and DMA
1184 should be numbers, or 'auto' (for using detected
1185 settings on that particular port), or 'nofifo'
1186 (to avoid using a FIFO even if it is detected).
1187 Parallel ports are assigned in the order they
1188 are specified on the command line, starting
1191 parport_init_mode= [HW,PPT]
1192 Configure VIA parallel port to operate in
1193 a specific mode. This is necessary on Pegasos
1194 computer where firmware has no options for setting
1195 up parallel port mode and sets it to spp.
1196 Currently this function knows 686a and 8231 chips.
1197 Format: [spp|ps2|epp|ecp|ecpepp]
1199 pas2= [HW,OSS] Format:
1200 <io>,<irq>,<dma>,<dma16>,<sb_io>,<sb_irq>,<sb_dma>,<sb_dma16>
1203 See header of drivers/scsi/pas16.c.
1206 Halt all CPUs after the first oops has been printed for
1207 the specified number of seconds. This is to be used if
1208 your oopses keep scrolling off the screen.
1213 See header of drivers/block/paride/pcd.c.
1214 See also Documentation/paride.txt.
1216 pci=option[,option...] [PCI] various PCI subsystem options:
1217 off [IA-32] don't probe for the PCI bus
1218 bios [IA-32] force use of PCI BIOS, don't access
1219 the hardware directly. Use this if your machine
1220 has a non-standard PCI host bridge.
1221 nobios [IA-32] disallow use of PCI BIOS, only direct
1222 hardware access methods are allowed. Use this
1223 if you experience crashes upon bootup and you
1224 suspect they are caused by the BIOS.
1225 conf1 [IA-32] Force use of PCI Configuration
1227 conf2 [IA-32] Force use of PCI Configuration
1229 nommconf [IA-32,X86_64] Disable use of MMCONFIG for PCI
1231 nomsi [MSI] If the PCI_MSI kernel config parameter is
1232 enabled, this kernel boot option can be used to
1233 disable the use of MSI interrupts system-wide.
1234 nosort [IA-32] Don't sort PCI devices according to
1235 order given by the PCI BIOS. This sorting is
1236 done to get a device order compatible with
1238 biosirq [IA-32] Use PCI BIOS calls to get the interrupt
1239 routing table. These calls are known to be buggy
1240 on several machines and they hang the machine
1241 when used, but on other computers it's the only
1242 way to get the interrupt routing table. Try
1243 this option if the kernel is unable to allocate
1244 IRQs or discover secondary PCI buses on your
1246 rom [IA-32] Assign address space to expansion ROMs.
1247 Use with caution as certain devices share
1248 address decoders between ROMs and other
1250 irqmask=0xMMMM [IA-32] Set a bit mask of IRQs allowed to be
1251 assigned automatically to PCI devices. You can
1252 make the kernel exclude IRQs of your ISA cards
1254 pirqaddr=0xAAAAA [IA-32] Specify the physical address
1255 of the PIRQ table (normally generated
1256 by the BIOS) if it is outside the
1257 F0000h-100000h range.
1258 lastbus=N [IA-32] Scan all buses thru bus #N. Can be
1259 useful if the kernel is unable to find your
1260 secondary buses and you want to tell it
1261 explicitly which ones they are.
1262 assign-busses [IA-32] Always assign all PCI bus
1263 numbers ourselves, overriding
1264 whatever the firmware may have done.
1265 usepirqmask [IA-32] Honor the possible IRQ mask stored
1266 in the BIOS $PIR table. This is needed on
1267 some systems with broken BIOSes, notably
1268 some HP Pavilion N5400 and Omnibook XE3
1269 notebooks. This will have no effect if ACPI
1270 IRQ routing is enabled.
1271 noacpi [IA-32] Do not use ACPI for IRQ routing
1272 or for PCI scanning.
1273 routeirq Do IRQ routing for all PCI devices.
1274 This is normally done in pci_enable_device(),
1275 so this option is a temporary workaround
1276 for broken drivers that don't call it.
1277 firmware [ARM] Do not re-enumerate the bus but instead
1278 just use the configuration from the
1279 bootloader. This is currently used on
1280 IXP2000 systems where the bus has to be
1281 configured a certain way for adjunct CPUs.
1282 noearly [X86] Don't do any early type 1 scanning.
1283 This might help on some broken boards which
1284 machine check when some devices' config space
1285 is read. But various workarounds are disabled
1286 and some IOMMU drivers will not work.
1287 bfsort Sort PCI devices into breadth-first order.
1288 This sorting is done to get a device
1289 order compatible with older (<= 2.4) kernels.
1290 nobfsort Don't sort PCI devices into breadth-first order.
1291 cbiosize=nn[KMG] The fixed amount of bus space which is
1292 reserved for the CardBus bridge's IO window.
1293 The default value is 256 bytes.
1294 cbmemsize=nn[KMG] The fixed amount of bus space which is
1295 reserved for the CardBus bridge's memory
1296 window. The default value is 64 megabytes.
1298 pcmv= [HW,PCMCIA] BadgePAD 4
1301 See Documentation/paride.txt.
1303 pdcchassis= [PARISC,HW] Disable/Enable PDC Chassis Status codes at
1306 See arch/parisc/kernel/pdc_chassis.c
1309 See Documentation/paride.txt.
1312 See Documentation/paride.txt.
1314 pirq= [SMP,APIC] Manual mp-table setup
1315 See Documentation/i386/IO-APIC.txt.
1317 plip= [PPT,NET] Parallel port network link
1318 Format: { parport<nr> | timid | 0 }
1319 See also Documentation/parport.txt.
1325 { on | off | curr | res | no-curr | no-res }
1328 [ISAPNP] Exclude IRQs for the autoconfiguration
1331 [ISAPNP] Exclude DMAs for the autoconfiguration
1333 pnp_reserve_io= [ISAPNP] Exclude I/O ports for the autoconfiguration
1334 Ranges are in pairs (I/O port base and size).
1337 [ISAPNP] Exclude memory regions for the
1339 Ranges are in pairs (memory base and size).
1341 profile= [KNL] Enable kernel profiling via /proc/profile
1342 Format: [schedule,]<number>
1343 Param: "schedule" - profile schedule points.
1344 Param: <number> - step/bucket size as a power of 2 for
1345 statistical time based profiling.
1346 Param: "sleep" - profile D-state sleeping (millisecs)
1348 processor.max_cstate= [HW,ACPI]
1349 Limit processor to maximum C-state
1350 max_cstate=9 overrides any DMI blacklist limit.
1352 processor.nocst [HW,ACPI]
1353 Ignore the _CST method to determine C-states,
1354 instead using the legacy FADT method
1356 prompt_ramdisk= [RAM] List of RAM disks to prompt for floppy disk
1358 See Documentation/ramdisk.txt.
1360 psmouse.proto= [HW,MOUSE] Highest PS2 mouse protocol extension to
1361 probe for; one of (bare|imps|exps|lifebook|any).
1362 psmouse.rate= [HW,MOUSE] Set desired mouse report rate, in reports
1364 psmouse.resetafter= [HW,MOUSE]
1365 Try to reset the device after so many bad packets
1368 [HW,MOUSE] Set desired mouse resolution, in dpi.
1369 psmouse.smartscroll=
1370 [HW,MOUSE] Controls Logitech smartscroll autorepeat.
1371 0 = disabled, 1 = enabled (default).
1373 pss= [HW,OSS] Personal Sound System (ECHO ESC614)
1375 <io>,<mss_io>,<mss_irq>,<mss_dma>,<mpu_io>,<mpu_irq>
1378 See Documentation/paride.txt.
1380 quiet [KNL] Disable most log messages
1385 See Documentation/md.txt.
1387 ramdisk= [RAM] Sizes of RAM disks in kilobytes [deprecated]
1388 See Documentation/ramdisk.txt.
1390 ramdisk_blocksize= [RAM]
1391 See Documentation/ramdisk.txt.
1393 ramdisk_size= [RAM] Sizes of RAM disks in kilobytes
1394 New name for the ramdisk parameter.
1395 See Documentation/ramdisk.txt.
1397 rcu.blimit= [KNL,BOOT] Set maximum number of finished
1398 RCU callbacks to process in one batch.
1400 rcu.qhimark= [KNL,BOOT] Set threshold of queued
1401 RCU callbacks over which batch limiting is disabled.
1403 rcu.qlowmark= [KNL,BOOT] Set threshold of queued
1404 RCU callbacks below which batch limiting is re-enabled.
1408 Run specified binary instead of /init from the ramdisk,
1409 used for early userspace startup. See initrd.
1411 reboot= [BUGS=IA-32,BUGS=ARM,BUGS=IA-64] Rebooting mode
1412 Format: <reboot_mode>[,<reboot_mode2>[,...]]
1413 See arch/*/kernel/reboot.c or arch/*/kernel/process.c
1415 reserve= [KNL,BUGS] Force the kernel to ignore some iomem area
1419 Reserves a hole at the top of the kernel virtual
1422 reset_devices [KNL] Force drivers to reset the underlying device
1423 during initialization.
1426 Specify the partition device for software suspend
1428 resume_offset= [SWSUSP]
1429 Specify the offset from the beginning of the partition
1430 given by "resume=" at which the swap header is located,
1431 in <PAGE_SIZE> units (needed only for swap files).
1432 See Documentation/power/swsusp-and-swap-files.txt
1434 retain_initrd [RAM] Keep initrd memory after extraction
1436 rhash_entries= [KNL,NET]
1437 Set number of hash buckets for route cache
1439 riscom8= [HW,SERIAL]
1440 Format: <io_board1>[,<io_board2>[,...<io_boardN>]]
1442 ro [KNL] Mount root device read-only on boot
1444 root= [KNL] Root filesystem
1446 rootdelay= [KNL] Delay (in seconds) to pause before attempting to
1447 mount the root filesystem
1449 rootflags= [KNL] Set root filesystem mount option string
1451 rootfstype= [KNL] Set root filesystem type
1453 rw [KNL] Mount root device read-write on boot
1455 S [KNL] Run init in single mode
1458 See drivers/net/irda/sa1100_ir.c.
1461 Format: <io>,<irq>,<dma>,<dma2>
1463 sbni= [NET] Granch SBNI12 leased line adapter
1465 sbpcd= [HW,CD] Soundblaster CD adapter
1467 See a comment before function sbpcd_setup() in
1468 drivers/cdrom/sbpcd.c.
1470 sc1200wdt= [HW,WDT] SC1200 WDT (watchdog) driver
1471 Format: <io>[,<timeout>[,<isapnp>]]
1473 scsi_debug_*= [SCSI]
1474 See drivers/scsi/scsi_debug.c.
1476 scsi_default_dev_flags=
1477 [SCSI] SCSI default device flags
1480 scsi_dev_flags= [SCSI] Black/white list entry for vendor and model
1481 Format: <vendor>:<model>:<flags>
1482 (flags are integer value)
1484 scsi_logging= [SCSI]
1486 scsi_mod.scan= [SCSI] sync (default) scans SCSI busses as they are
1487 discovered. async scans them in kernel threads,
1488 allowing boot to proceed. none ignores them, expecting
1489 user space to do the scan.
1491 selinux [SELINUX] Disable or enable SELinux at boot time.
1492 Format: { "0" | "1" }
1493 See security/selinux/Kconfig help text.
1496 Default value is set via kernel config option.
1497 If enabled at boot time, /selinux/disable can be used
1498 later to disable prior to initial policy load.
1500 selinux_compat_net =
1501 [SELINUX] Set initial selinux_compat_net flag value.
1502 Format: { "0" | "1" }
1503 0 -- use new secmark-based packet controls
1504 1 -- use legacy packet controls
1505 Default value is 0 (preferred).
1506 Value can be changed at runtime via
1507 /selinux/compat_net.
1509 serialnumber [BUGS=IA-32]
1511 sg_def_reserved_size= [SCSI]
1514 Maximal number of shapers.
1517 See header of drivers/scsi/sim710.c.
1523 Format: <io>,<irq>,<dma>
1524 See header of drivers/cdrom/sjcd.c.
1529 Format: <io1>[,<io2>[,...,<io8>]]
1531 snd-ad1816a= [HW,ALSA]
1533 snd-ad1848= [HW,ALSA]
1535 snd-ali5451= [HW,ALSA]
1537 snd-als100= [HW,ALSA]
1539 snd-als4000= [HW,ALSA]
1541 snd-azt2320= [HW,ALSA]
1543 snd-cmi8330= [HW,ALSA]
1545 snd-cmipci= [HW,ALSA]
1547 snd-cs4231= [HW,ALSA]
1549 snd-cs4232= [HW,ALSA]
1551 snd-cs4236= [HW,ALSA]
1553 snd-cs4281= [HW,ALSA]
1555 snd-cs46xx= [HW,ALSA]
1557 snd-dt019x= [HW,ALSA]
1559 snd-dummy= [HW,ALSA]
1561 snd-emu10k1= [HW,ALSA]
1563 snd-ens1370= [HW,ALSA]
1565 snd-ens1371= [HW,ALSA]
1567 snd-es968= [HW,ALSA]
1569 snd-es1688= [HW,ALSA]
1571 snd-es18xx= [HW,ALSA]
1573 snd-es1938= [HW,ALSA]
1575 snd-es1968= [HW,ALSA]
1577 snd-fm801= [HW,ALSA]
1579 snd-gusclassic= [HW,ALSA]
1581 snd-gusextreme= [HW,ALSA]
1583 snd-gusmax= [HW,ALSA]
1587 snd-ice1712= [HW,ALSA]
1589 snd-intel8x0= [HW,ALSA]
1591 snd-interwave= [HW,ALSA]
1596 snd-korg1212= [HW,ALSA]
1598 snd-maestro3= [HW,ALSA]
1600 snd-mpu401= [HW,ALSA]
1602 snd-mtpav= [HW,ALSA]
1604 snd-nm256= [HW,ALSA]
1606 snd-opl3sa2= [HW,ALSA]
1614 snd-opti93x= [HW,ALSA]
1618 snd-rme32= [HW,ALSA]
1620 snd-rme96= [HW,ALSA]
1622 snd-rme9652= [HW,ALSA]
1628 snd-sbawe= [HW,ALSA]
1630 snd-serial= [HW,ALSA]
1632 snd-sgalaxy= [HW,ALSA]
1634 snd-sonicvibes= [HW,ALSA]
1639 snd-sun-cs4231= [HW,ALSA]
1641 snd-trident= [HW,ALSA]
1643 snd-usb-audio= [HW,ALSA,USB]
1645 snd-via82xx= [HW,ALSA]
1647 snd-virmidi= [HW,ALSA]
1649 snd-wavefront= [HW,ALSA]
1651 snd-ymfpci= [HW,ALSA]
1654 Format: <io>[,<irq>]
1656 sonypi.*= [HW] Sony Programmable I/O Control Device driver
1657 See Documentation/sonypi.txt
1659 specialix= [HW,SERIAL] Specialix multi-serial port adapter
1660 See Documentation/specialix.txt.
1662 spia_io_base= [HW,MTD]
1668 Format: <io>,<irq>,<dma>,<mpu_io>,<mpu_irq>
1670 st= [HW,SCSI] SCSI tape parameters (buffers, etc.)
1671 See Documentation/scsi/st.txt.
1674 See header of drivers/scsi/seagate.c.
1678 Set the STI (builtin display/keyboard on the HP-PARISC
1679 machines) console (graphic card) which should be used
1680 as the initial boot-console.
1681 See also comment in drivers/video/console/sticore.c.
1684 See comment in drivers/video/console/sticore.c.
1687 Format: bpp:<bpp1>[:<bpp2>[:<bpp3>...]]
1691 Control how the NFS server code allocates CPUs to
1692 service thread pools. Depending on how many NICs
1693 you have and where their interrupts are bound, this
1694 option will affect which CPUs will do NFS serving.
1695 Note: this parameter cannot be changed while the
1696 NFS server is running.
1698 auto the server chooses an appropriate mode
1699 automatically using heuristics
1700 global a single global pool contains all CPUs
1701 percpu one pool for each CPU
1702 pernode one pool for each NUMA node (equivalent
1703 to global on non-NUMA machines)
1705 swiotlb= [IA-64] Number of I/O TLB slabs
1709 sym53c416= [HW,SCSI]
1710 See header of drivers/scsi/sym53c416.c.
1712 sysrq_always_enabled
1714 Ignore sysrq setting - this boot parameter will
1715 neutralize any effect of /proc/sys/kernel/sysrq.
1716 Useful for debugging.
1719 See header of drivers/scsi/t128.c.
1723 thash_entries= [KNL,NET]
1724 Set number of hash buckets for TCP connection
1726 time Show timing data prefixed to each printk message line
1728 clocksource= [GENERIC_TIME] Override the default clocksource
1729 Override the default clocksource and use the clocksource
1730 with the name specified.
1732 tipar.timeout= [HW,PPT]
1733 Set communications timeout in tenths of a second
1736 tipar.delay= [HW,PPT]
1737 Set inter-bit delay in microseconds (default 10).
1740 See header of drivers/scsi/seagate.c.
1743 See comment before function dc390_setup() in
1744 drivers/scsi/tmscsim.c.
1748 trix= [HW,OSS] MediaTrix AudioTrix Pro
1750 <io>,<irq>,<dma>,<dma2>,<sb_io>,<sb_irq>,<sb_dma>,<mpu_io>,<mpu_irq>
1752 tsdev.xres= [TS] Horizontal screen resolution.
1753 tsdev.yres= [TS] Vertical screen resolution.
1755 turbografx.map[2|3]= [HW,JOY]
1756 TurboGraFX parallel port interface
1758 <port#>,<js1>,<js2>,<js3>,<js4>,<js5>,<js6>,<js7>
1759 See also Documentation/input/joystick-parport.txt
1761 u14-34f= [HW,SCSI] UltraStor 14F/34F SCSI host adapter
1762 See header of drivers/scsi/u14-34f.c.
1771 [USB] Ignore overcurrent events (default N).
1772 Some badly-designed motherboards generate lots of
1773 bogus events, for ports that aren't wired to
1774 anything. Set this parameter to avoid log spamming.
1775 Note that genuine overcurrent events won't be
1778 usbcore.autosuspend=
1779 [USB] The autosuspend time delay (in seconds) used
1780 for newly-detected USB devices (default 2). This
1781 is the time required before an idle device will be
1782 autosuspended. Devices for which the delay is set
1783 to 0 won't be autosuspended at all.
1786 [USBHID] The interval which mice are to be polled at.
1789 vdso=1: enable VDSO (default)
1790 vdso=0: disable VDSO mapping
1792 video= [FB] Frame buffer configuration
1793 See Documentation/fb/modedb.txt.
1795 vga= [BOOT,IA-32] Select a particular video mode
1796 See Documentation/i386/boot.txt and
1797 Documentation/svga.txt.
1798 Use vga=ask for menu.
1799 This is actually a boot loader parameter; the value is
1800 passed to the kernel using a special protocol.
1802 vmalloc=nn[KMG] [KNL,BOOT] Forces the vmalloc area to have an exact
1803 size of <nn>. This can be used to increase the
1804 minimum size (128MB on x86). It can also be used to
1805 decrease the size and leave more room for directly
1808 vmhalt= [KNL,S390] Perform z/VM CP command after system halt.
1811 vmpanic= [KNL,S390] Perform z/VM CP command after kernel panic.
1814 vmpoff= [KNL,S390] Perform z/VM CP command after power off.
1817 waveartist= [HW,OSS]
1818 Format: <io>,<irq>,<dma>,<dma2>
1821 See header of drivers/scsi/wd33c93.c.
1824 See header of drivers/scsi/wd7000.c.
1827 See Documentation/watchdog/watchdog.txt.
1829 xd= [HW,XT] Original XT pre-IDE (RLL encoded) disks.
1830 xd_geo= See header of drivers/block/xd.c.
1832 xirc2ps_cs= [NET,PCMCIA]
1834 <irq>,<irq_mask>,<io>,<full_duplex>,<do_sound>,<lockup_hack>[,<irq2>[,<irq3>[,<irq4>]]]
1836 norandmaps Don't use address space randomization
1837 Equivalent to echo 0 > /proc/sys/kernel/randomize_va_space
1839 unwind_debug=N N > 0 will enable dwarf2 unwinder debugging
1840 This is useful to get more information why
1841 you got a "dwarf2 unwinder stuck"
1843 ______________________________________________________________________
1847 Add documentation for ALSA options.
1848 Add more DRM drivers.