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 LP Printer support is enabled.
52 LOOP Loopback device support is enabled.
53 M68k M68k architecture is enabled.
54 These options have more detailed description inside of
55 Documentation/m68k/kernel-options.txt.
56 MCA MCA bus support is enabled.
57 MDA MDA console support is enabled.
58 MOUSE Appropriate mouse support is enabled.
59 MSI Message Signaled Interrupts (PCI).
60 MTD MTD support is enabled.
61 NET Appropriate network support is enabled.
62 NUMA NUMA support is enabled.
63 GENERIC_TIME The generic timeofday code is enabled.
64 NFS Appropriate NFS support is enabled.
65 OSS OSS sound support is enabled.
66 PARIDE The ParIDE subsystem is enabled.
67 PARISC The PA-RISC architecture is enabled.
68 PCI PCI bus support is enabled.
69 PCMCIA The PCMCIA subsystem is enabled.
70 PNP Plug & Play support is enabled.
71 PPC PowerPC architecture is enabled.
72 PPT Parallel port support is enabled.
73 PS2 Appropriate PS/2 support is enabled.
74 RAM RAM disk support is enabled.
75 S390 S390 architecture is enabled.
76 SCSI Appropriate SCSI support is enabled.
77 A lot of drivers has their options described inside of
79 SELINUX SELinux support is enabled.
80 SERIAL Serial support is enabled.
81 SMP The kernel is an SMP kernel.
82 SPARC Sparc architecture is enabled.
83 SWSUSP Software suspend is enabled.
84 TS Appropriate touchscreen support is enabled.
85 USB USB support is enabled.
86 USBHID USB Human Interface Device support is enabled.
87 V4L Video For Linux support is enabled.
88 VGA The VGA console has been enabled.
89 VT Virtual terminal support is enabled.
90 WDT Watchdog support is enabled.
91 XT IBM PC/XT MFM hard disk support is enabled.
92 X86-64 X86-64 architecture is enabled.
93 More X86-64 boot options can be found in
94 Documentation/x86_64/boot-options.txt .
96 In addition, the following text indicates that the option:
98 BUGS= Relates to possible processor bugs on the said processor.
99 KNL Is a kernel start-up parameter.
100 BOOT Is a boot loader parameter.
102 Parameters denoted with BOOT are actually interpreted by the boot
103 loader, and have no meaning to the kernel directly.
104 Do not modify the syntax of boot loader parameters without extreme
105 need or coordination with <Documentation/i386/boot.txt>.
107 There are also arch-specific kernel-parameters not documented here.
108 See for example <Documentation/x86_64/boot-options.txt>.
110 Note that ALL kernel parameters listed below are CASE SENSITIVE, and that
111 a trailing = on the name of any parameter states that that parameter will
112 be entered as an environment variable, whereas its absence indicates that
113 it will appear as a kernel argument readable via /proc/cmdline by programs
114 running once the system is up.
116 The number of kernel parameters is not limited, but the length of the
117 complete command line (parameters including spaces etc.) is limited to
118 a fixed number of characters. This limit depends on the architecture
119 and is between 256 and 4096 characters. It is defined in the file
120 ./include/asm/setup.h as COMMAND_LINE_SIZE.
123 53c7xx= [HW,SCSI] Amiga SCSI controllers
124 See header of drivers/scsi/53c7xx.c.
125 See also Documentation/scsi/ncr53c7xx.txt.
127 acpi= [HW,ACPI] Advanced Configuration and Power Interface
128 Format: { force | off | ht | strict | noirq }
129 force -- enable ACPI if default was off
130 off -- disable ACPI if default was on
131 noirq -- do not use ACPI for IRQ routing
132 ht -- run only enough ACPI to enable Hyper Threading
133 strict -- Be less tolerant of platforms that are not
134 strictly ACPI specification compliant.
136 See also Documentation/pm.txt, pci=noacpi
138 acpi_sleep= [HW,ACPI] Sleep options
139 Format: { s3_bios, s3_mode }
140 See Documentation/power/video.txt
142 acpi_sci= [HW,ACPI] ACPI System Control Interrupt trigger mode
143 Format: { level | edge | high | low }
145 acpi_irq_balance [HW,ACPI]
146 ACPI will balance active IRQs
149 acpi_irq_nobalance [HW,ACPI]
150 ACPI will not move active IRQs (default)
153 acpi_irq_pci= [HW,ACPI] If irq_balance, clear listed IRQs for
155 Format: <irq>,<irq>...
157 acpi_irq_isa= [HW,ACPI] If irq_balance, mark listed IRQs used by ISA
158 Format: <irq>,<irq>...
160 acpi_os_name= [HW,ACPI] Tell ACPI BIOS the name of the OS
161 Format: To spoof as Windows 98: ="Microsoft Windows"
163 acpi_osi= [HW,ACPI] empty param disables _OSI
165 acpi_serialize [HW,ACPI] force serialization of AML methods
167 acpi_skip_timer_override [HW,ACPI]
168 Recognize and ignore IRQ0/pin2 Interrupt Override.
169 For broken nForce2 BIOS resulting in XT-PIC timer.
170 acpi_use_timer_override [HW,ACPI}
171 Use timer override. For some broken Nvidia NF5 boards
172 that require a timer override, but don't have
175 acpi_dbg_layer= [HW,ACPI]
177 Each bit of the <int> indicates an ACPI debug layer,
178 1: enable, 0: disable. It is useful for boot time
179 debugging. After system has booted up, it can be set
180 via /proc/acpi/debug_layer.
182 acpi_dbg_level= [HW,ACPI]
184 Each bit of the <int> indicates an ACPI debug level,
185 1: enable, 0: disable. It is useful for boot time
186 debugging. After system has booted up, it can be set
187 via /proc/acpi/debug_level.
189 acpi_fake_ecdt [HW,ACPI] Workaround failure due to BIOS lacking ECDT
191 acpi_generic_hotkey [HW,ACPI]
192 Allow consolidated generic hotkey driver to
193 override platform specific driver.
194 See also Documentation/acpi-hotkey.txt.
196 acpi_pm_good [IA-32,X86-64]
197 Override the pmtimer bug detection: force the kernel
198 to assume that this machine's pmtimer latches its value
199 and always returns good values.
201 enable_timer_pin_1 [i386,x86-64]
202 Enable PIN 1 of APIC timer
203 Can be useful to work around chipset bugs
204 (in particular on some ATI chipsets).
205 The kernel tries to set a reasonable default.
207 disable_timer_pin_1 [i386,x86-64]
208 Disable PIN 1 of APIC timer
209 Can be useful to work around chipset bugs.
212 Format: <io>,<irq>,<dma>,<dma2>
213 See also Documentation/sound/oss/AD1816.
216 Format: <io>,<irq>,<dma>,<dma2>,<type>
222 See header of drivers/scsi/advansys.c.
224 advwdt= [HW,WDT] Advantech WDT
225 Format: <iostart>,<iostop>
227 aedsp16= [HW,OSS] Audio Excel DSP 16
228 Format: <io>,<irq>,<dma>,<mss_io>,<mpu_io>,<mpu_irq>
229 See also header of sound/oss/aedsp16.c.
232 See Documentation/scsi/aha152x.txt.
235 Format: <portbase>[,<buson>,<busoff>[,<dmaspeed>]]
238 See Documentation/scsi/aic7xxx.txt.
241 See Documentation/scsi/aic79xx.txt.
243 amijoy.map= [HW,JOY] Amiga joystick support
244 Map of devices attached to JOY0DAT and JOY1DAT
246 See also Documentation/kernel/input/joystick.txt
248 analog.map= [HW,JOY] Analog joystick and gamepad support
249 Specifies type or capabilities of an analog joystick
250 connected to one of 16 gameports
251 Format: <type1>,<type2>,..<type16>
254 Power management functions (SPARCstation-4/5 + deriv.)
256 Disable APC CPU standby support. SPARCstation-Fox does
257 not play well with APC CPU idle - disable it if you have
258 APC and your system crashes randomly.
260 apic= [APIC,i386] Change the output verbosity whilst booting
261 Format: { quiet (default) | verbose | debug }
262 Change the amount of debugging information output
263 when initialising the APIC and IO-APIC components.
265 apm= [APM] Advanced Power Management
266 See header of arch/i386/kernel/apm.c.
271 arcrimi= [HW,NET] ARCnet - "RIM I" (entirely mem-mapped) cards
272 Format: <io>,<irq>,<nodeID>
276 atarimouse= [HW,MOUSE] Atari Mouse
278 atascsi= [HW,SCSI] Atari SCSI
280 atkbd.extra= [HW] Enable extra LEDs and keys on IBM RapidAccess,
281 EzKey and similar keyboards
283 atkbd.reset= [HW] Reset keyboard during initialization
285 atkbd.set= [HW] Select keyboard code set
286 Format: <int> (2 = AT (default), 3 = PS/2)
288 atkbd.scroll= [HW] Enable scroll wheel on MS Office and similar
291 atkbd.softraw= [HW] Choose between synthetic and real raw mode
292 Format: <bool> (0 = real, 1 = synthetic (default))
294 atkbd.softrepeat= [HW]
295 Use software keyboard repeat
299 aztcd= [HW,CD] Aztech CD268 CDROM driver
300 Format: <io>,0x79 (?)
302 baycom_epp= [HW,AX25]
305 baycom_par= [HW,AX25] BayCom Parallel Port AX.25 Modem
307 See header of drivers/net/hamradio/baycom_par.c.
309 baycom_ser_fdx= [HW,AX25]
310 BayCom Serial Port AX.25 Modem (Full Duplex Mode)
311 Format: <io>,<irq>,<mode>[,<baud>]
312 See header of drivers/net/hamradio/baycom_ser_fdx.c.
314 baycom_ser_hdx= [HW,AX25]
315 BayCom Serial Port AX.25 Modem (Half Duplex Mode)
316 Format: <io>,<irq>,<mode>
317 See header of drivers/net/hamradio/baycom_ser_hdx.c.
319 blkmtd_device= [HW,MTD]
325 bttv.card= [HW,V4L] bttv (bt848 + bt878 based grabber cards)
326 bttv.radio= Most important insmod options are available as
328 bttv.pll= See Documentation/video4linux/bttv/Insmod-options
329 bttv.tuner= and Documentation/video4linux/bttv/CARDLIST
332 See drivers/scsi/BusLogic.c, comment before function
333 BusLogic_ParseDriverOptions().
335 c101= [NET] Moxa C101 synchronous serial card
337 cachesize= [BUGS=IA-32] Override level 2 CPU cache size detection.
338 Sometimes CPU hardware bugs make them report the cache
339 size incorrectly. The kernel will attempt work arounds
340 to fix known problems, but for some CPUs it is not
341 possible to determine what the correct size should be.
342 This option provides an override for these situations.
345 Format: <io>,<irq>[,PAS]
346 See header of drivers/cdrom/cdu31a.c.
348 chandev= [HW,NET] Generic channel device initialisation
350 checkreqprot [SELINUX] Set initial checkreqprot flag value.
351 Format: { "0" | "1" }
352 See security/selinux/Kconfig help text.
353 0 -- check protection applied by kernel (includes
354 any implied execute protection).
355 1 -- check protection requested by application.
356 Default value is set via a kernel config option.
357 Value can be changed at runtime via
358 /selinux/checkreqprot.
360 clock= [BUGS=IA-32, HW] gettimeofday clocksource override.
362 Forces specified clocksource (if available) to be used
363 when calculating gettimeofday(). If specified
364 clocksource is not available, it defaults to PIT.
365 Format: { pit | tsc | cyclone | pmtmr }
367 code_bytes [IA32] How many bytes of object code to print in an
374 [IA32/X86_64] Disable/Enable interrupt 0 timer routing
375 over the 8254 in addition to over the IO-APIC. The
376 kernel tries to set a sensible default.
378 hpet= [IA-32,HPET] option to disable HPET and use PIT.
382 Format: { auto | [<io>,][<irq>] }
384 com20020= [HW,NET] ARCnet - COM20020 chipset
386 <io>[,<irq>[,<nodeID>[,<backplane>[,<ckp>[,<timeout>]]]]]
388 com90io= [HW,NET] ARCnet - COM90xx chipset (IO-mapped buffers)
392 ARCnet - COM90xx chipset (memory-mapped buffers)
393 Format: <io>[,<irq>[,<memstart>]]
395 condev= [HW,S390] console device
398 console= [KNL] Output console device and options.
400 tty<n> Use the virtual console device <n>.
404 Use the specified serial port. The options are of
405 the form "bbbbpnf", where "bbbb" is the baud rate,
406 "p" is parity ("n", "o", or "e"), "n" is number of
407 bits, and "f" is flow control ("r" for RTS or
408 omit it). Default is "9600n8".
410 See Documentation/serial-console.txt for more
412 Documentation/networking/netconsole.txt for an
415 uart,io,<addr>[,options]
416 uart,mmio,<addr>[,options]
417 Start an early, polled-mode console on the 8250/16550
418 UART at the specified I/O port or MMIO address,
419 switching to the matching ttyS device later. The
420 options are the same as for ttyS, above.
422 cpcihp_generic= [HW,PCI] Generic port I/O CompactPCI driver
424 <first_slot>,<last_slot>,<port>,<enum_bit>[,<debug>]
427 Format: { parport<nr> | auto | none }
429 crashkernel=nn[KMG]@ss[KMG]
430 [KNL] Reserve a chunk of physical memory to
431 hold a kernel to switch to with kexec on panic.
434 Format: <io>,<irq>,<dma>,<dma2>,<mpuio>,<mpuirq>
439 cs89x0_media= [HW,NET]
440 Format: { rj45 | aui | bnc }
442 cyclades= [HW,SERIAL] Cyclades multi-serial port adapter.
445 See header of drivers/s390/block/dasd_devmap.c.
447 db9.dev[2|3]= [HW,JOY] Multisystem joystick support via parallel port
448 (one device per port)
449 Format: <port#>,<type>
450 See also Documentation/input/joystick-parport.txt
452 debug [KNL] Enable kernel debugging (events log level).
455 [KNL] verbose self-tests
457 Print debugging info while doing the locking API
459 We default to 0 (no extra messages), setting it to
460 1 will print _a lot_ more information - normally
461 only useful to kernel developers.
464 Format: <area>[,<node>]
465 See also Documentation/networking/decnet.txt.
468 Set number of hash buckets for dentry cache.
471 IO parameters + enable/disable command.
473 digiepca= [HW,SERIAL]
474 See drivers/char/README.epca and
475 Documentation/digiepca.txt.
477 dmascc= [HW,AX25,SERIAL] AX.25 Z80SCC driver with DMA
479 Format: <io_dev0>[,<io_dev1>[,..<io_dev32>]]
481 dmasound= [HW,OSS] Sound subsystem buffers
487 earlyprintk= [IA-32,X86-64]
489 earlyprintk=serial[,ttySn[,baudrate]]
491 Append ",keep" to not disable it when the real console
494 Only vga or serial at a time, not both.
496 Currently only ttyS0 and ttyS1 are supported.
498 Interaction with the standard serial driver is not
501 The VGA output is eventually overwritten by the real
506 ec_intr= [HW,ACPI] ACPI Embedded Controller interrupt mode
509 non-0: interrupt mode (default)
516 Format: {"of[f]" | "sk[ipmbr]"}
517 See comment in arch/i386/boot/edd.S
520 Format: <id>,<membase>,<irq>
522 eisa_irq_edge= [PARISC,HW]
523 See header of drivers/parisc/eisa.c.
526 See comment before function elanfreq_setup() in
527 arch/i386/kernel/cpu/cpufreq/elanfreq.c.
530 Format: {"anticipatory" | "cfq" | "deadline" | "noop"}
531 See Documentation/block/as-iosched.txt and
532 Documentation/block/deadline-iosched.txt for details.
534 elfcorehdr= [IA-32, X86_64]
535 Specifies physical address of start of kernel core
536 image elf header. Generally kexec loader will
537 pass this option to capture kernel.
538 See Documentation/kdump/kdump.txt for details.
540 enforcing [SELINUX] Set initial enforcing status.
542 See security/selinux/Kconfig help text.
543 0 -- permissive (log only, no denials).
544 1 -- enforcing (deny and log).
546 Value can be changed at runtime via /selinux/enforce.
549 Format: <spdif>,[<nomix>,[<amplifier>]]
550 See also header of sound/oss/es1371.c.
552 ether= [HW,NET] Ethernet cards parameters
553 This option is obsoleted by the "netdev=" option, which
554 has equivalent usage. See its documentation for details.
556 eurwdt= [HW,WDT] Eurotech CPU-1220/1410 onboard watchdog.
561 fail_make_request=[KNL]
562 General fault injection mechanism.
563 Format: <interval>,<probability>,<space>,<times>
564 See also /Documentation/fault-injection/.
567 See header of drivers/scsi/fd_mcs.c.
570 See header of drivers/scsi/fdomain.c.
573 See Documentation/floppy.txt.
576 [HW,JOY] Multisystem joystick and NES/SNES/PSX pad
577 support via parallel port (up to 5 devices per port)
578 Format: <port#>,<pad1>,<pad2>,<pad3>,<pad4>,<pad5>
579 See also Documentation/input/joystick-parport.txt
584 See header of drivers/scsi/gdth.c.
586 gpt [EFI] Forces disk with valid GPT signature but
587 invalid Protective MBR to be treated as GPT.
594 hashdist= [KNL,NUMA] Large hashes allocated during boot
595 are distributed across NUMA nodes. Defaults on
596 for IA-64, off otherwise.
597 Format: 0 | 1 (for off | on)
599 hcl= [IA-64] SGI's Hardware Graph compatibility layer
601 hd= [EIDE] (E)IDE hard drive subsystem geometry
602 Format: <cyl>,<head>,<sect>
604 hd?= [HW] (E)IDE subsystem
605 hd?lun= See Documentation/ide.txt.
607 highmem=nn[KMG] [KNL,BOOT] forces the highmem zone to have an exact
608 size of <nn>. This works even on boxes that have no
609 highmem otherwise. This also works to reduce highmem
610 size on bigger boxes.
612 highres= [KNL] Enable/disable high resolution timer mode.
613 Valid parameters: "on", "off"
617 See Documentation/isdn/README.HiSax.
619 hugepages= [HW,IA-32,IA-64] Maximal number of HugeTLB pages.
621 i8042.direct [HW] Put keyboard port into non-translated mode
622 i8042.dumbkbd [HW] Pretend that controller can only read data from
623 keyboard and cannot control its state
624 (Don't attempt to blink the leds)
625 i8042.noaux [HW] Don't check for auxiliary (== mouse) port
626 i8042.nokbd [HW] Don't check/create keyboard port
627 i8042.nomux [HW] Don't check presence of an active multiplexing
629 i8042.nopnp [HW] Don't use ACPIPnP / PnPBIOS to discover KBD/AUX
632 [HW] Frequency with which keyboard LEDs should blink
633 when kernel panics (default is 0.5 sec)
634 i8042.reset [HW] Reset the controller during init and cleanup
635 i8042.unlock [HW] Unlock (ignore) the keylock
639 i8k.ignore_dmi [HW] Continue probing hardware even if DMI data
640 indicates that the driver is running on unsupported
642 i8k.force [HW] Activate i8k driver even if SMM BIOS signature
643 does not match list of supported models.
645 [HW] Report power status in /proc/i8k
646 (disabled by default)
647 i8k.restricted [HW] Allow controlling fans only if SYS_ADMIN
650 ibmmcascsi= [HW,MCA,SCSI] IBM MicroChannel SCSI adapter
651 See Documentation/mca.txt.
654 Format: <io>[,<membase>[,<icn_id>[,<icn_id2>]]]
656 ide= [HW] (E)IDE subsystem
657 Format: ide=nodma or ide=doubler or ide=reverse
658 See Documentation/ide.txt.
660 ide?= [HW] (E)IDE subsystem
661 Format: ide?=noprobe or chipset specific parameters.
662 See Documentation/ide.txt.
664 idebus= [HW] (E)IDE subsystem - VLB/PCI bus speed
665 See Documentation/ide.txt.
668 Format: idle=poll or idle=halt
670 ignore_loglevel [KNL]
671 Ignore loglevel setting - this will print /all/
672 kernel messages to the console. Useful for debugging.
675 Set number of hash buckets for inode cache.
678 See header of drivers/scsi/in2000.c.
682 Run specified binary instead of /sbin/init as init
685 initcall_debug [KNL] Trace initcalls as they are executed. Useful
686 for working out where the kernel is dying during
689 initrd= [BOOT] Specify the location of the initial ramdisk
691 inport.irq= [HW] Inport (ATI XL and Microsoft) busmouse driver
694 combined_mode= [HW] control which driver uses IDE ports in combined
695 mode: legacy IDE driver, libata, or both
696 (in the libata case, libata.atapi_enabled=1 may be
697 useful as well). Note that using the ide or libata
698 options may affect your device naming (e.g. by
699 changing hdc to sdb).
700 Format: combined (default), ide, or libata
704 io7= [HW] IO7 for Marvel based alpha systems
705 See comment before marvel_specify_io7 in
706 arch/alpha/kernel/core_marvel.c.
709 See Documentation/nfsroot.txt.
711 ip2= [HW] Set IO/IRQ pairs for up to 4 IntelliPort boards
712 See comment before ip2_setup() in drivers/char/ip2.c.
714 ips= [HW,SCSI] Adaptec / IBM ServeRAID controller
715 See header of drivers/scsi/ips.c.
717 ports= [IP_VS_FTP] IPVS ftp helper module
719 Up to 8 (IP_VS_APP_MAX_PORTS) ports
721 Format: <port>,<port>....
724 When an interrupt is not handled search all handlers
725 for it. Intended to get systems with badly broken
729 When an interrupt is not handled search all handlers
730 for it. Also check all handlers each timer
731 interrupt. Intended to get systems with badly broken
735 Format: <RDP>,<reset>,<pci_scan>,<verbosity>
737 isolcpus= [KNL,SMP] Isolate CPUs from the general scheduler.
739 <cpu number>,...,<cpu number>
741 <cpu number>-<cpu number> (must be a positive range in ascending order)
743 <cpu number>,...,<cpu number>-<cpu number>
744 This option can be used to specify one or more CPUs
745 to isolate from the general SMP balancing and scheduling
746 algorithms. The only way to move a process onto or off
747 an "isolated" CPU is via the CPU affinity syscalls.
748 <cpu number> begins at 0 and the maximum value is
749 "number of CPUs in system - 1".
751 This option is the preferred way to isolate CPUs. The
752 alternative -- manually setting the CPU mask of all
753 tasks in the system -- can cause problems and
754 suboptimal load balancer performance.
757 Format: <io>,<irq>,<dma>,<setup>
761 js= [HW,JOY] Analog joystick
762 See Documentation/input/joystick.txt.
766 kstack=N [IA-32,X86-64] Print N words from the kernel stack
771 lapic [IA-32,APIC] Enable the local APIC even if BIOS
774 lasi= [HW,SCSI] PARISC LASI driver for the 53c700 chip
775 Format: addr:<io>,irq:<irq>
777 llsc*= [IA64] See function print_params() in
778 arch/ia64/sn/kernel/llsc4.c.
780 load_ramdisk= [RAM] List of ramdisks to load from floppy
781 See Documentation/ramdisk.txt.
783 lockd.nlm_grace_period=P [NFS] Assign grace period.
786 lockd.nlm_tcpport=N [NFS] Assign TCP port.
789 lockd.nlm_timeout=T [NFS] Assign timeout value.
792 lockd.nlm_udpport=M [NFS] Assign UDP port.
795 logibm.irq= [HW,MOUSE] Logitech Bus Mouse Driver
798 loglevel= All Kernel Messages with a loglevel smaller than the
799 console loglevel will be printed to the console. It can
800 also be changed with klogd or other programs. The
801 loglevels are defined as follows:
803 0 (KERN_EMERG) system is unusable
804 1 (KERN_ALERT) action must be taken immediately
805 2 (KERN_CRIT) critical conditions
806 3 (KERN_ERR) error conditions
807 4 (KERN_WARNING) warning conditions
808 5 (KERN_NOTICE) normal but significant condition
809 6 (KERN_INFO) informational
810 7 (KERN_DEBUG) debug-level messages
812 log_buf_len=n Sets the size of the printk ring buffer, in bytes.
813 Format: { n | nk | nM }
814 n must be a power of two. The default size
815 is set in the kernel config file.
817 lp=0 [LP] Specify parallel ports to use, e.g,
818 lp=port[,port...] lp=none,parport0 (lp0 not configured, lp1 uses
819 lp=reset first parallel port). 'lp=0' disables the
820 lp=auto printer driver. 'lp=reset' (which can be
821 specified in addition to the ports) causes
822 attached printers to be reset. Using
823 lp=port1,port2,... specifies the parallel ports
824 to associate lp devices with, starting with
825 lp0. A port specification may be 'none' to skip
826 that lp device, or a parport name such as
827 'parport0'. Specifying 'lp=auto' instead of a
828 port specification list means that device IDs
829 from each port should be examined, to see if
830 an IEEE 1284-compliant printer is attached; if
831 so, the driver will manage that printer.
832 See also header of drivers/char/lp.c.
835 Sets loops_per_jiffy to given constant, thus avoiding
836 time-consuming boot-time autodetection (up to 250 ms per
837 CPU). 0 enables autodetection (default). To determine
838 the correct value for your kernel, boot with normal
839 autodetection and see what value is printed. Note that
840 on SMP systems the preset will be applied to all CPUs,
841 which is likely to cause problems if your CPUs need
842 significantly divergent settings. An incorrect value
843 will cause delays in the kernel to be wrong, leading to
844 unpredictable I/O errors and other breakage. Although
845 unlikely, in the extreme case this might damage your
849 Format: <io>,<irq>,<dma>
851 mac5380= [HW,SCSI] Format:
852 <can_queue>,<cmd_per_lun>,<sg_tablesize>,<hostid>,<use_tags>
854 mac53c9x= [HW,SCSI] Format:
855 <num_esps>,<disconnect>,<nosync>,<can_queue>,<cmd_per_lun>,<sg_tablesize>,<hostid>,<use_tags>
857 machvec= [IA64] Force the use of a particular machine-vector
858 (machvec) in a generic kernel.
859 Example: machvec=hpzx1_swiotlb
861 max_loop= [LOOP] Maximum number of loopback devices that can
865 maxcpus= [SMP] Maximum number of processors that an SMP kernel
867 Using "nosmp" or "maxcpus=0" will disable SMP
868 entirely (the MPS table probe still happens, though).
869 A command-line option of "maxcpus=<NUM>", where <NUM>
870 is an integer greater than 0, limits the maximum number
871 of CPUs activated in SMP mode to <NUM>.
872 Using "maxcpus=1" on an SMP kernel is the trivial
873 case of an SMP kernel with only one CPU.
875 max_addr=[KMG] [KNL,BOOT,ia64] All physical memory greater than or
876 equal to this physical address is ignored.
878 max_luns= [SCSI] Maximum number of LUNs to probe.
879 Should be between 1 and 2^32-1.
882 [SCSI] Maximum number of LUNs received.
883 Should be between 1 and 16384.
885 mca-pentium [BUGS=IA-32]
890 Format: <port>,<irq>,<mitsumi_bug_93_wait>
894 mce [IA-32] Machine Check Exception
896 md= [HW] RAID subsystems devices and level
897 See Documentation/md.txt.
900 Format: <first>,<last>
901 Specifies range of consoles to be captured by the MDA.
903 mem=nn[KMG] [KNL,BOOT] Force usage of a specific amount of memory
904 Amount of memory to be used when the kernel is not able
905 to see the whole system memory or for test.
906 [IA-32] Use together with memmap= to avoid physical
907 address space collisions. Without memmap= PCI devices
908 could be placed at addresses belonging to unused RAM.
910 mem=nopentium [BUGS=IA-32] Disable usage of 4MB pages for kernel
913 memmap=exactmap [KNL,IA-32,X86_64] Enable setting of an exact
914 E820 memory map, as specified by the user.
915 Such memmap=exactmap lines can be constructed based on
916 BIOS output or other requirements. See the memmap=nn@ss
919 memmap=nn[KMG]@ss[KMG]
920 [KNL] Force usage of a specific region of memory
921 Region of memory to be used, from ss to ss+nn.
923 memmap=nn[KMG]#ss[KMG]
924 [KNL,ACPI] Mark specific memory as ACPI data.
925 Region of memory to be used, from ss to ss+nn.
927 memmap=nn[KMG]$ss[KMG]
928 [KNL,ACPI] Mark specific memory as reserved.
929 Region of memory to be used, from ss to ss+nn.
931 meye.*= [HW] Set MotionEye Camera parameters
932 See Documentation/video4linux/meye.txt.
937 [KNL,SMP] debug: override scheduler migration costs
938 Format: <level-1-usecs>,<level-2-usecs>,...
939 This debugging option can be used to override the
940 default scheduler migration cost matrix. The numbers
941 are indexed by 'CPU domain distance'.
942 E.g. migration_cost=1000,2000,3000 on an SMT NUMA
943 box will set up an intra-core migration cost of
944 1 msec, an inter-core migration cost of 2 msecs,
945 and an inter-node migration cost of 3 msecs.
947 WARNING: using the wrong values here can break
948 scheduler performance, so it's only for scheduler
949 development purposes, not production environments.
952 [KNL,SMP] migration cost auto-detect verbosity
954 If a system's migration matrix reported at bootup
955 seems erroneous then this option can be used to
956 increase verbosity of the detection process.
957 We default to 0 (no extra messages), 1 will print
958 some more information, and 2 will be really
959 verbose (probably only useful if you also have a
960 serial console attached to the system).
963 [KNL,SMP] multiply/divide migration costs by a factor
965 This debug option can be used to proportionally
966 increase or decrease the auto-detected migration
967 costs for all entries of the migration matrix.
968 E.g. migration_factor=150 will increase migration
969 costs by 50%. (and thus the scheduler will be less
970 eager migrating cache-hot tasks)
971 migration_factor=80 will decrease migration costs
972 by 20%. (thus the scheduler will be more eager to
975 WARNING: using the wrong values here can break
976 scheduler performance, so it's only for scheduler
977 development purposes, not production environments.
980 [MOUSE] Maximum time between finger touching and
981 leaving touchpad surface for touch to be considered
982 a tap and be reported as a left button click (for
983 touchpads working in absolute mode only).
985 mousedev.xres= [MOUSE] Horizontal screen resolution, used for devices
986 reporting absolute coordinates, such as tablets
987 mousedev.yres= [MOUSE] Vertical screen resolution, used for devices
988 reporting absolute coordinates, such as tablets
994 Format: <name>,<region-number>,<size>,<offset>
996 MTD_Region= [MTD] Format:
997 <name>,<region-number>[,<base>,<size>,<buswidth>,<altbuswidth>]
1000 See drivers/mtd/cmdline.c.
1002 mtouchusb.raw_coordinates=
1003 [HW] Make the MicroTouch USB driver use raw coordinates
1004 ('y', default) or cooked coordinates ('n')
1006 n2= [NET] SDL Inc. RISCom/N2 synchronous serial card
1009 See header of drivers/scsi/NCR_D700.c.
1013 ncr53c400= [HW,SCSI]
1015 ncr53c400a= [HW,SCSI]
1017 ncr53c406a= [HW,SCSI]
1019 ncr53c8xx= [HW,SCSI]
1021 netdev= [NET] Network devices parameters
1022 Format: <irq>,<io>,<mem_start>,<mem_end>,<name>
1023 Note that mem_start is often overloaded to mean
1024 something different and driver-specific.
1025 This usage is only documented in each driver source
1029 See Documentation/nfsroot.txt.
1031 nfsroot= [NFS] nfs root filesystem for disk-less boxes.
1032 See Documentation/nfsroot.txt.
1034 nfs.callback_tcpport=
1035 [NFS] set the TCP port on which the NFSv4 callback
1036 channel should listen.
1038 nfs.idmap_cache_timeout=
1039 [NFS] set the maximum lifetime for idmapper cache
1042 nmi_watchdog= [KNL,BUGS=IA-32] Debugging features for SMP kernels
1044 no387 [BUGS=IA-32] Tells the kernel to use the 387 maths
1045 emulation library even if a 387 maths coprocessor
1048 noaliencache [MM, NUMA] Disables the allcoation of alien caches in
1049 the slab allocator. Saves per-node memory, but will
1050 impact performance on real NUMA hardware.
1054 noapic [SMP,APIC] Tells the kernel to not make use of any
1055 IOAPICs that may be present in the system.
1057 noasync [HW,M68K] Disables async and sync negotiation for
1060 nobats [PPC] Do not use BATs for mapping kernel lowmem
1061 on "Classic" PPC cores.
1065 nodelayacct [KNL] Disable per-task delay accounting
1067 nodisconnect [HW,SCSI,M68K] Disables SCSI disconnects.
1071 noexec [IA-32,X86-64]
1072 noexec=on: enable non-executable mappings (default)
1073 noexec=off: disable nn-executable mappings
1075 nofxsr [BUGS=IA-32] Disables x86 floating point extended
1076 register save and restore. The kernel will only save
1077 legacy floating-point registers on task switch.
1081 no-hlt [BUGS=IA-32] Tells the kernel that the hlt
1082 instruction doesn't work correctly and not to
1085 nohalt [IA-64] Tells the kernel not to use the power saving
1086 function PAL_HALT_LIGHT when idle. This increases
1087 power-consumption. On the positive side, it reduces
1088 interrupt wake-up latency, which may improve performance
1089 in certain environments such as networked servers or
1092 nohz= [KNL] Boottime enable/disable dynamic ticks
1093 Valid arguments: on, off
1096 noirqbalance [IA-32,SMP,KNL] Disable kernel irq balancing
1098 noirqdebug [IA-32] Disables the code which attempts to detect and
1099 disable unhandled interrupt sources.
1101 no_timer_check [IA-32,X86_64,APIC] Disables the code which tests for
1102 broken timer IRQ sources.
1104 noisapnp [ISAPNP] Disables ISA PnP code.
1106 noinitrd [RAM] Tells the kernel not to load any configured
1111 nolapic [IA-32,APIC] Do not enable or use the local APIC.
1113 noltlbs [PPC] Do not use large page/tlb entries for kernel
1114 lowmem mapping on PPC40x.
1116 nomca [IA-64] Disable machine check abort handling
1118 nomce [IA-32] Machine Check Exception
1120 noresidual [PPC] Don't use residual data on PReP machines.
1122 noresume [SWSUSP] Disables resume and restores original swap
1125 no-scroll [VGA] Disables scrollback.
1126 This is required for the Braillex ib80-piezo Braille
1127 reader made by F.H. Papenmeier (Germany).
1131 nosep [BUGS=IA-32] Disables x86 SYSENTER/SYSEXIT support.
1133 nosmp [SMP] Tells an SMP kernel to act as a UP kernel.
1135 nosync [HW,M68K] Disables sync negotiation for all devices.
1137 notsc [BUGS=IA-32] Disable Time Stamp Counter
1139 nousb [USB] Disable the USB subsystem
1143 nr_uarts= [SERIAL] maximum number of UARTs to be registered.
1148 opl3sa2= [HW,OSS] Format:
1149 <io>,<irq>,<dma>,<dma2>,<mss_io>,<mpu_io>,<ymode>,<loopback>[,<isapnp>,<multiple]
1151 oprofile.timer= [HW]
1152 Use timer interrupt instead of performance counters
1157 osst= [HW,SCSI] SCSI Tape Driver
1158 Format: <buffer_size>,<write_threshold>
1159 See also Documentation/scsi/st.txt.
1161 panic= [KNL] Kernel behaviour on panic
1164 parkbd.port= [HW] Parallel port number the keyboard adapter is
1165 connected to, default is 0.
1167 parkbd.mode= [HW] Parallel port keyboard adapter mode of operation,
1168 0 for XT, 1 for AT (default is AT).
1171 parport= [HW,PPT] Specify parallel ports. 0 disables.
1172 Format: { 0 | auto | 0xBBB[,IRQ[,DMA]] }
1173 Use 'auto' to force the driver to use any
1174 IRQ/DMA settings detected (the default is to
1175 ignore detected IRQ/DMA settings because of
1176 possible conflicts). You can specify the base
1177 address, IRQ, and DMA settings; IRQ and DMA
1178 should be numbers, or 'auto' (for using detected
1179 settings on that particular port), or 'nofifo'
1180 (to avoid using a FIFO even if it is detected).
1181 Parallel ports are assigned in the order they
1182 are specified on the command line, starting
1185 parport_init_mode= [HW,PPT]
1186 Configure VIA parallel port to operate in
1187 a specific mode. This is necessary on Pegasos
1188 computer where firmware has no options for setting
1189 up parallel port mode and sets it to spp.
1190 Currently this function knows 686a and 8231 chips.
1191 Format: [spp|ps2|epp|ecp|ecpepp]
1193 pas2= [HW,OSS] Format:
1194 <io>,<irq>,<dma>,<dma16>,<sb_io>,<sb_irq>,<sb_dma>,<sb_dma16>
1197 See header of drivers/scsi/pas16.c.
1200 Halt all CPUs after the first oops has been printed for
1201 the specified number of seconds. This is to be used if
1202 your oopses keep scrolling off the screen.
1207 See header of drivers/block/paride/pcd.c.
1208 See also Documentation/paride.txt.
1210 pci=option[,option...] [PCI] various PCI subsystem options:
1211 off [IA-32] don't probe for the PCI bus
1212 bios [IA-32] force use of PCI BIOS, don't access
1213 the hardware directly. Use this if your machine
1214 has a non-standard PCI host bridge.
1215 nobios [IA-32] disallow use of PCI BIOS, only direct
1216 hardware access methods are allowed. Use this
1217 if you experience crashes upon bootup and you
1218 suspect they are caused by the BIOS.
1219 conf1 [IA-32] Force use of PCI Configuration
1221 conf2 [IA-32] Force use of PCI Configuration
1223 nommconf [IA-32,X86_64] Disable use of MMCONFIG for PCI
1225 nomsi [MSI] If the PCI_MSI kernel config parameter is
1226 enabled, this kernel boot option can be used to
1227 disable the use of MSI interrupts system-wide.
1228 nosort [IA-32] Don't sort PCI devices according to
1229 order given by the PCI BIOS. This sorting is
1230 done to get a device order compatible with
1232 biosirq [IA-32] Use PCI BIOS calls to get the interrupt
1233 routing table. These calls are known to be buggy
1234 on several machines and they hang the machine
1235 when used, but on other computers it's the only
1236 way to get the interrupt routing table. Try
1237 this option if the kernel is unable to allocate
1238 IRQs or discover secondary PCI buses on your
1240 rom [IA-32] Assign address space to expansion ROMs.
1241 Use with caution as certain devices share
1242 address decoders between ROMs and other
1244 irqmask=0xMMMM [IA-32] Set a bit mask of IRQs allowed to be
1245 assigned automatically to PCI devices. You can
1246 make the kernel exclude IRQs of your ISA cards
1248 pirqaddr=0xAAAAA [IA-32] Specify the physical address
1249 of the PIRQ table (normally generated
1250 by the BIOS) if it is outside the
1251 F0000h-100000h range.
1252 lastbus=N [IA-32] Scan all buses thru bus #N. Can be
1253 useful if the kernel is unable to find your
1254 secondary buses and you want to tell it
1255 explicitly which ones they are.
1256 assign-busses [IA-32] Always assign all PCI bus
1257 numbers ourselves, overriding
1258 whatever the firmware may have done.
1259 usepirqmask [IA-32] Honor the possible IRQ mask stored
1260 in the BIOS $PIR table. This is needed on
1261 some systems with broken BIOSes, notably
1262 some HP Pavilion N5400 and Omnibook XE3
1263 notebooks. This will have no effect if ACPI
1264 IRQ routing is enabled.
1265 noacpi [IA-32] Do not use ACPI for IRQ routing
1266 or for PCI scanning.
1267 routeirq Do IRQ routing for all PCI devices.
1268 This is normally done in pci_enable_device(),
1269 so this option is a temporary workaround
1270 for broken drivers that don't call it.
1271 firmware [ARM] Do not re-enumerate the bus but instead
1272 just use the configuration from the
1273 bootloader. This is currently used on
1274 IXP2000 systems where the bus has to be
1275 configured a certain way for adjunct CPUs.
1276 noearly [X86] Don't do any early type 1 scanning.
1277 This might help on some broken boards which
1278 machine check when some devices' config space
1279 is read. But various workarounds are disabled
1280 and some IOMMU drivers will not work.
1281 bfsort Sort PCI devices into breadth-first order.
1282 This sorting is done to get a device
1283 order compatible with older (<= 2.4) kernels.
1284 nobfsort Don't sort PCI devices into breadth-first order.
1286 pcmv= [HW,PCMCIA] BadgePAD 4
1289 See Documentation/paride.txt.
1291 pdcchassis= [PARISC,HW] Disable/Enable PDC Chassis Status codes at
1294 See arch/parisc/kernel/pdc_chassis.c
1297 See Documentation/paride.txt.
1300 See Documentation/paride.txt.
1302 pirq= [SMP,APIC] Manual mp-table setup
1303 See Documentation/i386/IO-APIC.txt.
1305 plip= [PPT,NET] Parallel port network link
1306 Format: { parport<nr> | timid | 0 }
1307 See also Documentation/parport.txt.
1313 { on | off | curr | res | no-curr | no-res }
1316 [ISAPNP] Exclude IRQs for the autoconfiguration
1319 [ISAPNP] Exclude DMAs for the autoconfiguration
1321 pnp_reserve_io= [ISAPNP] Exclude I/O ports for the autoconfiguration
1322 Ranges are in pairs (I/O port base and size).
1325 [ISAPNP] Exclude memory regions for the
1327 Ranges are in pairs (memory base and size).
1329 profile= [KNL] Enable kernel profiling via /proc/profile
1330 Format: [schedule,]<number>
1331 Param: "schedule" - profile schedule points.
1332 Param: <number> - step/bucket size as a power of 2 for
1333 statistical time based profiling.
1334 Param: "sleep" - profile D-state sleeping (millisecs)
1336 processor.max_cstate= [HW,ACPI]
1337 Limit processor to maximum C-state
1338 max_cstate=9 overrides any DMI blacklist limit.
1340 processor.nocst [HW,ACPI]
1341 Ignore the _CST method to determine C-states,
1342 instead using the legacy FADT method
1344 prompt_ramdisk= [RAM] List of RAM disks to prompt for floppy disk
1346 See Documentation/ramdisk.txt.
1348 psmouse.proto= [HW,MOUSE] Highest PS2 mouse protocol extension to
1349 probe for; one of (bare|imps|exps|lifebook|any).
1350 psmouse.rate= [HW,MOUSE] Set desired mouse report rate, in reports
1352 psmouse.resetafter= [HW,MOUSE]
1353 Try to reset the device after so many bad packets
1356 [HW,MOUSE] Set desired mouse resolution, in dpi.
1357 psmouse.smartscroll=
1358 [HW,MOUSE] Controls Logitech smartscroll autorepeat.
1359 0 = disabled, 1 = enabled (default).
1361 pss= [HW,OSS] Personal Sound System (ECHO ESC614)
1363 <io>,<mss_io>,<mss_irq>,<mss_dma>,<mpu_io>,<mpu_irq>
1366 See Documentation/paride.txt.
1368 quiet [KNL] Disable most log messages
1373 See Documentation/md.txt.
1375 ramdisk= [RAM] Sizes of RAM disks in kilobytes [deprecated]
1376 See Documentation/ramdisk.txt.
1378 ramdisk_blocksize= [RAM]
1379 See Documentation/ramdisk.txt.
1381 ramdisk_size= [RAM] Sizes of RAM disks in kilobytes
1382 New name for the ramdisk parameter.
1383 See Documentation/ramdisk.txt.
1385 rcu.blimit= [KNL,BOOT] Set maximum number of finished
1386 RCU callbacks to process in one batch.
1388 rcu.qhimark= [KNL,BOOT] Set threshold of queued
1389 RCU callbacks over which batch limiting is disabled.
1391 rcu.qlowmark= [KNL,BOOT] Set threshold of queued
1392 RCU callbacks below which batch limiting is re-enabled.
1396 Run specified binary instead of /init from the ramdisk,
1397 used for early userspace startup. See initrd.
1399 reboot= [BUGS=IA-32,BUGS=ARM,BUGS=IA-64] Rebooting mode
1400 Format: <reboot_mode>[,<reboot_mode2>[,...]]
1401 See arch/*/kernel/reboot.c or arch/*/kernel/process.c
1403 reserve= [KNL,BUGS] Force the kernel to ignore some iomem area
1407 Reserves a hole at the top of the kernel virtual
1410 reset_devices [KNL] Force drivers to reset the underlying device
1411 during initialization.
1414 Specify the partition device for software suspend
1416 resume_offset= [SWSUSP]
1417 Specify the offset from the beginning of the partition
1418 given by "resume=" at which the swap header is located,
1419 in <PAGE_SIZE> units (needed only for swap files).
1420 See Documentation/power/swsusp-and-swap-files.txt
1422 retain_initrd [RAM] Keep initrd memory after extraction
1424 rhash_entries= [KNL,NET]
1425 Set number of hash buckets for route cache
1427 riscom8= [HW,SERIAL]
1428 Format: <io_board1>[,<io_board2>[,...<io_boardN>]]
1430 ro [KNL] Mount root device read-only on boot
1432 root= [KNL] Root filesystem
1434 rootdelay= [KNL] Delay (in seconds) to pause before attempting to
1435 mount the root filesystem
1437 rootflags= [KNL] Set root filesystem mount option string
1439 rootfstype= [KNL] Set root filesystem type
1441 rw [KNL] Mount root device read-write on boot
1443 S [KNL] Run init in single mode
1446 See drivers/net/irda/sa1100_ir.c.
1449 Format: <io>,<irq>,<dma>,<dma2>
1451 sbni= [NET] Granch SBNI12 leased line adapter
1453 sbpcd= [HW,CD] Soundblaster CD adapter
1455 See a comment before function sbpcd_setup() in
1456 drivers/cdrom/sbpcd.c.
1458 sc1200wdt= [HW,WDT] SC1200 WDT (watchdog) driver
1459 Format: <io>[,<timeout>[,<isapnp>]]
1461 scsi_debug_*= [SCSI]
1462 See drivers/scsi/scsi_debug.c.
1464 scsi_default_dev_flags=
1465 [SCSI] SCSI default device flags
1468 scsi_dev_flags= [SCSI] Black/white list entry for vendor and model
1469 Format: <vendor>:<model>:<flags>
1470 (flags are integer value)
1472 scsi_logging= [SCSI]
1474 scsi_mod.scan= [SCSI] sync (default) scans SCSI busses as they are
1475 discovered. async scans them in kernel threads,
1476 allowing boot to proceed. none ignores them, expecting
1477 user space to do the scan.
1479 selinux [SELINUX] Disable or enable SELinux at boot time.
1480 Format: { "0" | "1" }
1481 See security/selinux/Kconfig help text.
1484 Default value is set via kernel config option.
1485 If enabled at boot time, /selinux/disable can be used
1486 later to disable prior to initial policy load.
1488 selinux_compat_net =
1489 [SELINUX] Set initial selinux_compat_net flag value.
1490 Format: { "0" | "1" }
1491 0 -- use new secmark-based packet controls
1492 1 -- use legacy packet controls
1493 Default value is 0 (preferred).
1494 Value can be changed at runtime via
1495 /selinux/compat_net.
1497 serialnumber [BUGS=IA-32]
1499 sg_def_reserved_size= [SCSI]
1502 Maximal number of shapers.
1505 See header of drivers/scsi/sim710.c.
1511 Format: <io>,<irq>,<dma>
1512 See header of drivers/cdrom/sjcd.c.
1517 Format: <io1>[,<io2>[,...,<io8>]]
1519 snd-ad1816a= [HW,ALSA]
1521 snd-ad1848= [HW,ALSA]
1523 snd-ali5451= [HW,ALSA]
1525 snd-als100= [HW,ALSA]
1527 snd-als4000= [HW,ALSA]
1529 snd-azt2320= [HW,ALSA]
1531 snd-cmi8330= [HW,ALSA]
1533 snd-cmipci= [HW,ALSA]
1535 snd-cs4231= [HW,ALSA]
1537 snd-cs4232= [HW,ALSA]
1539 snd-cs4236= [HW,ALSA]
1541 snd-cs4281= [HW,ALSA]
1543 snd-cs46xx= [HW,ALSA]
1545 snd-dt019x= [HW,ALSA]
1547 snd-dummy= [HW,ALSA]
1549 snd-emu10k1= [HW,ALSA]
1551 snd-ens1370= [HW,ALSA]
1553 snd-ens1371= [HW,ALSA]
1555 snd-es968= [HW,ALSA]
1557 snd-es1688= [HW,ALSA]
1559 snd-es18xx= [HW,ALSA]
1561 snd-es1938= [HW,ALSA]
1563 snd-es1968= [HW,ALSA]
1565 snd-fm801= [HW,ALSA]
1567 snd-gusclassic= [HW,ALSA]
1569 snd-gusextreme= [HW,ALSA]
1571 snd-gusmax= [HW,ALSA]
1575 snd-ice1712= [HW,ALSA]
1577 snd-intel8x0= [HW,ALSA]
1579 snd-interwave= [HW,ALSA]
1584 snd-korg1212= [HW,ALSA]
1586 snd-maestro3= [HW,ALSA]
1588 snd-mpu401= [HW,ALSA]
1590 snd-mtpav= [HW,ALSA]
1592 snd-nm256= [HW,ALSA]
1594 snd-opl3sa2= [HW,ALSA]
1602 snd-opti93x= [HW,ALSA]
1606 snd-rme32= [HW,ALSA]
1608 snd-rme96= [HW,ALSA]
1610 snd-rme9652= [HW,ALSA]
1616 snd-sbawe= [HW,ALSA]
1618 snd-serial= [HW,ALSA]
1620 snd-sgalaxy= [HW,ALSA]
1622 snd-sonicvibes= [HW,ALSA]
1627 snd-sun-cs4231= [HW,ALSA]
1629 snd-trident= [HW,ALSA]
1631 snd-usb-audio= [HW,ALSA,USB]
1633 snd-via82xx= [HW,ALSA]
1635 snd-virmidi= [HW,ALSA]
1637 snd-wavefront= [HW,ALSA]
1639 snd-ymfpci= [HW,ALSA]
1642 Format: <io>[,<irq>]
1644 sonypi.*= [HW] Sony Programmable I/O Control Device driver
1645 See Documentation/sonypi.txt
1647 specialix= [HW,SERIAL] Specialix multi-serial port adapter
1648 See Documentation/specialix.txt.
1650 spia_io_base= [HW,MTD]
1656 Format: <io>,<irq>,<dma>,<mpu_io>,<mpu_irq>
1658 st= [HW,SCSI] SCSI tape parameters (buffers, etc.)
1659 See Documentation/scsi/st.txt.
1662 See header of drivers/scsi/seagate.c.
1666 Set the STI (builtin display/keyboard on the HP-PARISC
1667 machines) console (graphic card) which should be used
1668 as the initial boot-console.
1669 See also comment in drivers/video/console/sticore.c.
1672 See comment in drivers/video/console/sticore.c.
1675 Format: bpp:<bpp1>[:<bpp2>[:<bpp3>...]]
1677 swiotlb= [IA-64] Number of I/O TLB slabs
1681 sym53c416= [HW,SCSI]
1682 See header of drivers/scsi/sym53c416.c.
1684 sysrq_always_enabled
1686 Ignore sysrq setting - this boot parameter will
1687 neutralize any effect of /proc/sys/kernel/sysrq.
1688 Useful for debugging.
1691 See header of drivers/scsi/t128.c.
1695 thash_entries= [KNL,NET]
1696 Set number of hash buckets for TCP connection
1698 time Show timing data prefixed to each printk message line
1700 clocksource= [GENERIC_TIME] Override the default clocksource
1701 Override the default clocksource and use the clocksource
1702 with the name specified.
1704 tipar.timeout= [HW,PPT]
1705 Set communications timeout in tenths of a second
1708 tipar.delay= [HW,PPT]
1709 Set inter-bit delay in microseconds (default 10).
1712 See header of drivers/scsi/seagate.c.
1715 See comment before function dc390_setup() in
1716 drivers/scsi/tmscsim.c.
1720 trix= [HW,OSS] MediaTrix AudioTrix Pro
1722 <io>,<irq>,<dma>,<dma2>,<sb_io>,<sb_irq>,<sb_dma>,<mpu_io>,<mpu_irq>
1724 tsdev.xres= [TS] Horizontal screen resolution.
1725 tsdev.yres= [TS] Vertical screen resolution.
1727 turbografx.map[2|3]= [HW,JOY]
1728 TurboGraFX parallel port interface
1730 <port#>,<js1>,<js2>,<js3>,<js4>,<js5>,<js6>,<js7>
1731 See also Documentation/input/joystick-parport.txt
1733 u14-34f= [HW,SCSI] UltraStor 14F/34F SCSI host adapter
1734 See header of drivers/scsi/u14-34f.c.
1743 [USB] Ignore overcurrent events (default N).
1744 Some badly-designed motherboards generate lots of
1745 bogus events, for ports that aren't wired to
1746 anything. Set this parameter to avoid log spamming.
1747 Note that genuine overcurrent events won't be
1751 [USBHID] The interval which mice are to be polled at.
1754 vdso=1: enable VDSO (default)
1755 vdso=0: disable VDSO mapping
1757 video= [FB] Frame buffer configuration
1758 See Documentation/fb/modedb.txt.
1760 vga= [BOOT,IA-32] Select a particular video mode
1761 See Documentation/i386/boot.txt and
1762 Documentation/svga.txt.
1763 Use vga=ask for menu.
1764 This is actually a boot loader parameter; the value is
1765 passed to the kernel using a special protocol.
1767 vmalloc=nn[KMG] [KNL,BOOT] Forces the vmalloc area to have an exact
1768 size of <nn>. This can be used to increase the
1769 minimum size (128MB on x86). It can also be used to
1770 decrease the size and leave more room for directly
1773 vmhalt= [KNL,S390] Perform z/VM CP command after system halt.
1776 vmpanic= [KNL,S390] Perform z/VM CP command after kernel panic.
1779 vmpoff= [KNL,S390] Perform z/VM CP command after power off.
1782 waveartist= [HW,OSS]
1783 Format: <io>,<irq>,<dma>,<dma2>
1786 See header of drivers/scsi/wd33c93.c.
1789 See header of drivers/scsi/wd7000.c.
1792 See Documentation/watchdog/watchdog.txt.
1794 xd= [HW,XT] Original XT pre-IDE (RLL encoded) disks.
1795 xd_geo= See header of drivers/block/xd.c.
1797 xirc2ps_cs= [NET,PCMCIA]
1799 <irq>,<irq_mask>,<io>,<full_duplex>,<do_sound>,<lockup_hack>[,<irq2>[,<irq3>[,<irq4>]]]
1801 norandmaps Don't use address space randomization
1802 Equivalent to echo 0 > /proc/sys/kernel/randomize_va_space
1804 unwind_debug=N N > 0 will enable dwarf2 unwinder debugging
1805 This is useful to get more information why
1806 you got a "dwarf2 unwinder stuck"
1808 ______________________________________________________________________
1812 Add documentation for ALSA options.
1813 Add more DRM drivers.