kernel-parameters.txt 51 KB

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  1. Kernel Parameters
  2. ~~~~~~~~~~~~~~~~~
  3. The following is a consolidated list of the kernel parameters as implemented
  4. (mostly) by the __setup() macro and sorted into English Dictionary order
  5. (defined as ignoring all punctuation and sorting digits before letters in a
  6. case insensitive manner), and with descriptions where known.
  7. Module parameters for loadable modules are specified only as the
  8. parameter name with optional '=' and value as appropriate, such as:
  9. modprobe usbcore blinkenlights=1
  10. Module parameters for modules that are built into the kernel image
  11. are specified on the kernel command line with the module name plus
  12. '.' plus parameter name, with '=' and value if appropriate, such as:
  13. usbcore.blinkenlights=1
  14. This document may not be entirely up to date and comprehensive. The command
  15. "modinfo -p ${modulename}" shows a current list of all parameters of a loadable
  16. module. Loadable modules, after being loaded into the running kernel, also
  17. reveal their parameters in /sys/module/${modulename}/parameters/. Some of these
  18. parameters may be changed at runtime by the command
  19. "echo -n ${value} > /sys/module/${modulename}/parameters/${parm}".
  20. The parameters listed below are only valid if certain kernel build options were
  21. enabled and if respective hardware is present. The text in square brackets at
  22. the beginning of each description states the restrictions within which a
  23. parameter is applicable:
  24. ACPI ACPI support is enabled.
  25. ALSA ALSA sound support is enabled.
  26. APIC APIC support is enabled.
  27. APM Advanced Power Management support is enabled.
  28. AX25 Appropriate AX.25 support is enabled.
  29. CD Appropriate CD support is enabled.
  30. DRM Direct Rendering Management support is enabled.
  31. EDD BIOS Enhanced Disk Drive Services (EDD) is enabled
  32. EFI EFI Partitioning (GPT) is enabled
  33. EIDE EIDE/ATAPI support is enabled.
  34. FB The frame buffer device is enabled.
  35. HW Appropriate hardware is enabled.
  36. IA-32 IA-32 aka i386 architecture is enabled.
  37. IA-64 IA-64 architecture is enabled.
  38. IOSCHED More than one I/O scheduler is enabled.
  39. IP_PNP IP DHCP, BOOTP, or RARP is enabled.
  40. ISAPNP ISA PnP code is enabled.
  41. ISDN Appropriate ISDN support is enabled.
  42. JOY Appropriate joystick support is enabled.
  43. LP Printer support is enabled.
  44. LOOP Loopback device support is enabled.
  45. M68k M68k architecture is enabled.
  46. These options have more detailed description inside of
  47. Documentation/m68k/kernel-options.txt.
  48. MCA MCA bus support is enabled.
  49. MDA MDA console support is enabled.
  50. MOUSE Appropriate mouse support is enabled.
  51. MSI Message Signaled Interrupts (PCI).
  52. MTD MTD support is enabled.
  53. NET Appropriate network support is enabled.
  54. NUMA NUMA support is enabled.
  55. GENERIC_TIME The generic timeofday code is enabled.
  56. NFS Appropriate NFS support is enabled.
  57. OSS OSS sound support is enabled.
  58. PARIDE The ParIDE subsystem is enabled.
  59. PARISC The PA-RISC architecture is enabled.
  60. PCI PCI bus support is enabled.
  61. PCMCIA The PCMCIA subsystem is enabled.
  62. PNP Plug & Play support is enabled.
  63. PPC PowerPC architecture is enabled.
  64. PPT Parallel port support is enabled.
  65. PS2 Appropriate PS/2 support is enabled.
  66. RAM RAM disk support is enabled.
  67. S390 S390 architecture is enabled.
  68. SCSI Appropriate SCSI support is enabled.
  69. A lot of drivers has their options described inside of
  70. Documentation/scsi/.
  71. SELINUX SELinux support is enabled.
  72. SERIAL Serial support is enabled.
  73. SMP The kernel is an SMP kernel.
  74. SPARC Sparc architecture is enabled.
  75. SWSUSP Software suspend is enabled.
  76. TS Appropriate touchscreen support is enabled.
  77. USB USB support is enabled.
  78. USBHID USB Human Interface Device support is enabled.
  79. V4L Video For Linux support is enabled.
  80. VGA The VGA console has been enabled.
  81. VT Virtual terminal support is enabled.
  82. WDT Watchdog support is enabled.
  83. XT IBM PC/XT MFM hard disk support is enabled.
  84. X86-64 X86-64 architecture is enabled.
  85. More X86-64 boot options can be found in
  86. Documentation/x86_64/boot-options.txt .
  87. In addition, the following text indicates that the option:
  88. BUGS= Relates to possible processor bugs on the said processor.
  89. KNL Is a kernel start-up parameter.
  90. BOOT Is a boot loader parameter.
  91. Parameters denoted with BOOT are actually interpreted by the boot
  92. loader, and have no meaning to the kernel directly.
  93. Do not modify the syntax of boot loader parameters without extreme
  94. need or coordination with <Documentation/i386/boot.txt>.
  95. Note that ALL kernel parameters listed below are CASE SENSITIVE, and that
  96. a trailing = on the name of any parameter states that that parameter will
  97. be entered as an environment variable, whereas its absence indicates that
  98. it will appear as a kernel argument readable via /proc/cmdline by programs
  99. running once the system is up.
  100. The number of kernel parameters is not limited, but the length of the
  101. complete command line (parameters including spaces etc.) is limited to
  102. a fixed number of characters. This limit depends on the architecture
  103. and is between 256 and 4096 characters. It is defined in the file
  104. ./include/asm/setup.h as COMMAND_LINE_SIZE.
  105. 53c7xx= [HW,SCSI] Amiga SCSI controllers
  106. See header of drivers/scsi/53c7xx.c.
  107. See also Documentation/scsi/ncr53c7xx.txt.
  108. acpi= [HW,ACPI] Advanced Configuration and Power Interface
  109. Format: { force | off | ht | strict | noirq }
  110. force -- enable ACPI if default was off
  111. off -- disable ACPI if default was on
  112. noirq -- do not use ACPI for IRQ routing
  113. ht -- run only enough ACPI to enable Hyper Threading
  114. strict -- Be less tolerant of platforms that are not
  115. strictly ACPI specification compliant.
  116. See also Documentation/pm.txt, pci=noacpi
  117. acpi_sleep= [HW,ACPI] Sleep options
  118. Format: { s3_bios, s3_mode }
  119. See Documentation/power/video.txt
  120. acpi_sci= [HW,ACPI] ACPI System Control Interrupt trigger mode
  121. Format: { level | edge | high | low }
  122. acpi_irq_balance [HW,ACPI]
  123. ACPI will balance active IRQs
  124. default in APIC mode
  125. acpi_irq_nobalance [HW,ACPI]
  126. ACPI will not move active IRQs (default)
  127. default in PIC mode
  128. acpi_irq_pci= [HW,ACPI] If irq_balance, clear listed IRQs for
  129. use by PCI
  130. Format: <irq>,<irq>...
  131. acpi_irq_isa= [HW,ACPI] If irq_balance, mark listed IRQs used by ISA
  132. Format: <irq>,<irq>...
  133. acpi_os_name= [HW,ACPI] Tell ACPI BIOS the name of the OS
  134. Format: To spoof as Windows 98: ="Microsoft Windows"
  135. acpi_osi= [HW,ACPI] empty param disables _OSI
  136. acpi_serialize [HW,ACPI] force serialization of AML methods
  137. acpi_skip_timer_override [HW,ACPI]
  138. Recognize and ignore IRQ0/pin2 Interrupt Override.
  139. For broken nForce2 BIOS resulting in XT-PIC timer.
  140. acpi_use_timer_override [HW,ACPI}
  141. Use timer override. For some broken Nvidia NF5 boards
  142. that require a timer override, but don't have
  143. HPET
  144. acpi_dbg_layer= [HW,ACPI]
  145. Format: <int>
  146. Each bit of the <int> indicates an ACPI debug layer,
  147. 1: enable, 0: disable. It is useful for boot time
  148. debugging. After system has booted up, it can be set
  149. via /proc/acpi/debug_layer.
  150. acpi_dbg_level= [HW,ACPI]
  151. Format: <int>
  152. Each bit of the <int> indicates an ACPI debug level,
  153. 1: enable, 0: disable. It is useful for boot time
  154. debugging. After system has booted up, it can be set
  155. via /proc/acpi/debug_level.
  156. acpi_fake_ecdt [HW,ACPI] Workaround failure due to BIOS lacking ECDT
  157. acpi_generic_hotkey [HW,ACPI]
  158. Allow consolidated generic hotkey driver to
  159. override platform specific driver.
  160. See also Documentation/acpi-hotkey.txt.
  161. acpi_pm_good [IA-32,X86-64]
  162. Override the pmtimer bug detection: force the kernel
  163. to assume that this machine's pmtimer latches its value
  164. and always returns good values.
  165. enable_timer_pin_1 [i386,x86-64]
  166. Enable PIN 1 of APIC timer
  167. Can be useful to work around chipset bugs
  168. (in particular on some ATI chipsets).
  169. The kernel tries to set a reasonable default.
  170. disable_timer_pin_1 [i386,x86-64]
  171. Disable PIN 1 of APIC timer
  172. Can be useful to work around chipset bugs.
  173. ad1816= [HW,OSS]
  174. Format: <io>,<irq>,<dma>,<dma2>
  175. See also Documentation/sound/oss/AD1816.
  176. ad1848= [HW,OSS]
  177. Format: <io>,<irq>,<dma>,<dma2>,<type>
  178. adlib= [HW,OSS]
  179. Format: <io>
  180. advansys= [HW,SCSI]
  181. See header of drivers/scsi/advansys.c.
  182. advwdt= [HW,WDT] Advantech WDT
  183. Format: <iostart>,<iostop>
  184. aedsp16= [HW,OSS] Audio Excel DSP 16
  185. Format: <io>,<irq>,<dma>,<mss_io>,<mpu_io>,<mpu_irq>
  186. See also header of sound/oss/aedsp16.c.
  187. aha152x= [HW,SCSI]
  188. See Documentation/scsi/aha152x.txt.
  189. aha1542= [HW,SCSI]
  190. Format: <portbase>[,<buson>,<busoff>[,<dmaspeed>]]
  191. aic7xxx= [HW,SCSI]
  192. See Documentation/scsi/aic7xxx.txt.
  193. aic79xx= [HW,SCSI]
  194. See Documentation/scsi/aic79xx.txt.
  195. amijoy.map= [HW,JOY] Amiga joystick support
  196. Map of devices attached to JOY0DAT and JOY1DAT
  197. Format: <a>,<b>
  198. See also Documentation/kernel/input/joystick.txt
  199. analog.map= [HW,JOY] Analog joystick and gamepad support
  200. Specifies type or capabilities of an analog joystick
  201. connected to one of 16 gameports
  202. Format: <type1>,<type2>,..<type16>
  203. apc= [HW,SPARC]
  204. Power management functions (SPARCstation-4/5 + deriv.)
  205. Format: noidle
  206. Disable APC CPU standby support. SPARCstation-Fox does
  207. not play well with APC CPU idle - disable it if you have
  208. APC and your system crashes randomly.
  209. apic= [APIC,i386] Change the output verbosity whilst booting
  210. Format: { quiet (default) | verbose | debug }
  211. Change the amount of debugging information output
  212. when initialising the APIC and IO-APIC components.
  213. apm= [APM] Advanced Power Management
  214. See header of arch/i386/kernel/apm.c.
  215. applicom= [HW]
  216. Format: <mem>,<irq>
  217. arcrimi= [HW,NET] ARCnet - "RIM I" (entirely mem-mapped) cards
  218. Format: <io>,<irq>,<nodeID>
  219. ataflop= [HW,M68k]
  220. atarimouse= [HW,MOUSE] Atari Mouse
  221. atascsi= [HW,SCSI] Atari SCSI
  222. atkbd.extra= [HW] Enable extra LEDs and keys on IBM RapidAccess,
  223. EzKey and similar keyboards
  224. atkbd.reset= [HW] Reset keyboard during initialization
  225. atkbd.set= [HW] Select keyboard code set
  226. Format: <int> (2 = AT (default), 3 = PS/2)
  227. atkbd.scroll= [HW] Enable scroll wheel on MS Office and similar
  228. keyboards
  229. atkbd.softraw= [HW] Choose between synthetic and real raw mode
  230. Format: <bool> (0 = real, 1 = synthetic (default))
  231. atkbd.softrepeat= [HW]
  232. Use software keyboard repeat
  233. autotest [IA64]
  234. aztcd= [HW,CD] Aztech CD268 CDROM driver
  235. Format: <io>,0x79 (?)
  236. baycom_epp= [HW,AX25]
  237. Format: <io>,<mode>
  238. baycom_par= [HW,AX25] BayCom Parallel Port AX.25 Modem
  239. Format: <io>,<mode>
  240. See header of drivers/net/hamradio/baycom_par.c.
  241. baycom_ser_fdx= [HW,AX25]
  242. BayCom Serial Port AX.25 Modem (Full Duplex Mode)
  243. Format: <io>,<irq>,<mode>[,<baud>]
  244. See header of drivers/net/hamradio/baycom_ser_fdx.c.
  245. baycom_ser_hdx= [HW,AX25]
  246. BayCom Serial Port AX.25 Modem (Half Duplex Mode)
  247. Format: <io>,<irq>,<mode>
  248. See header of drivers/net/hamradio/baycom_ser_hdx.c.
  249. blkmtd_device= [HW,MTD]
  250. blkmtd_erasesz=
  251. blkmtd_ro=
  252. blkmtd_bs=
  253. blkmtd_count=
  254. bttv.card= [HW,V4L] bttv (bt848 + bt878 based grabber cards)
  255. bttv.radio= Most important insmod options are available as
  256. kernel args too.
  257. bttv.pll= See Documentation/video4linux/bttv/Insmod-options
  258. bttv.tuner= and Documentation/video4linux/bttv/CARDLIST
  259. BusLogic= [HW,SCSI]
  260. See drivers/scsi/BusLogic.c, comment before function
  261. BusLogic_ParseDriverOptions().
  262. c101= [NET] Moxa C101 synchronous serial card
  263. cachesize= [BUGS=IA-32] Override level 2 CPU cache size detection.
  264. Sometimes CPU hardware bugs make them report the cache
  265. size incorrectly. The kernel will attempt work arounds
  266. to fix known problems, but for some CPUs it is not
  267. possible to determine what the correct size should be.
  268. This option provides an override for these situations.
  269. cdu31a= [HW,CD]
  270. Format: <io>,<irq>[,PAS]
  271. See header of drivers/cdrom/cdu31a.c.
  272. chandev= [HW,NET] Generic channel device initialisation
  273. checkreqprot [SELINUX] Set initial checkreqprot flag value.
  274. Format: { "0" | "1" }
  275. See security/selinux/Kconfig help text.
  276. 0 -- check protection applied by kernel (includes
  277. any implied execute protection).
  278. 1 -- check protection requested by application.
  279. Default value is set via a kernel config option.
  280. Value can be changed at runtime via
  281. /selinux/checkreqprot.
  282. clock= [BUGS=IA-32, HW] gettimeofday clocksource override.
  283. [Deprecated]
  284. Forces specified clocksource (if available) to be used
  285. when calculating gettimeofday(). If specified
  286. clocksource is not available, it defaults to PIT.
  287. Format: { pit | tsc | cyclone | pmtmr }
  288. disable_8254_timer
  289. enable_8254_timer
  290. [IA32/X86_64] Disable/Enable interrupt 0 timer routing
  291. over the 8254 in addition to over the IO-APIC. The
  292. kernel tries to set a sensible default.
  293. hpet= [IA-32,HPET] option to disable HPET and use PIT.
  294. Format: disable
  295. cm206= [HW,CD]
  296. Format: { auto | [<io>,][<irq>] }
  297. com20020= [HW,NET] ARCnet - COM20020 chipset
  298. Format:
  299. <io>[,<irq>[,<nodeID>[,<backplane>[,<ckp>[,<timeout>]]]]]
  300. com90io= [HW,NET] ARCnet - COM90xx chipset (IO-mapped buffers)
  301. Format: <io>[,<irq>]
  302. com90xx= [HW,NET]
  303. ARCnet - COM90xx chipset (memory-mapped buffers)
  304. Format: <io>[,<irq>[,<memstart>]]
  305. condev= [HW,S390] console device
  306. conmode=
  307. console= [KNL] Output console device and options.
  308. tty<n> Use the virtual console device <n>.
  309. ttyS<n>[,options]
  310. ttyUSB0[,options]
  311. Use the specified serial port. The options are of
  312. the form "bbbbpnf", where "bbbb" is the baud rate,
  313. "p" is parity ("n", "o", or "e"), "n" is number of
  314. bits, and "f" is flow control ("r" for RTS or
  315. omit it). Default is "9600n8".
  316. See Documentation/serial-console.txt for more
  317. information. See
  318. Documentation/networking/netconsole.txt for an
  319. alternative.
  320. uart,io,<addr>[,options]
  321. uart,mmio,<addr>[,options]
  322. Start an early, polled-mode console on the 8250/16550
  323. UART at the specified I/O port or MMIO address,
  324. switching to the matching ttyS device later. The
  325. options are the same as for ttyS, above.
  326. cpcihp_generic= [HW,PCI] Generic port I/O CompactPCI driver
  327. Format:
  328. <first_slot>,<last_slot>,<port>,<enum_bit>[,<debug>]
  329. cpia_pp= [HW,PPT]
  330. Format: { parport<nr> | auto | none }
  331. crashkernel=nn[KMG]@ss[KMG]
  332. [KNL] Reserve a chunk of physical memory to
  333. hold a kernel to switch to with kexec on panic.
  334. cs4232= [HW,OSS]
  335. Format: <io>,<irq>,<dma>,<dma2>,<mpuio>,<mpuirq>
  336. cs89x0_dma= [HW,NET]
  337. Format: <dma>
  338. cs89x0_media= [HW,NET]
  339. Format: { rj45 | aui | bnc }
  340. cyclades= [HW,SERIAL] Cyclades multi-serial port adapter.
  341. dasd= [HW,NET]
  342. See header of drivers/s390/block/dasd_devmap.c.
  343. db9.dev[2|3]= [HW,JOY] Multisystem joystick support via parallel port
  344. (one device per port)
  345. Format: <port#>,<type>
  346. See also Documentation/input/joystick-parport.txt
  347. debug [KNL] Enable kernel debugging (events log level).
  348. debug_locks_verbose=
  349. [KNL] verbose self-tests
  350. Format=<0|1>
  351. Print debugging info while doing the locking API
  352. self-tests.
  353. We default to 0 (no extra messages), setting it to
  354. 1 will print _a lot_ more information - normally
  355. only useful to kernel developers.
  356. decnet= [HW,NET]
  357. Format: <area>[,<node>]
  358. See also Documentation/networking/decnet.txt.
  359. dhash_entries= [KNL]
  360. Set number of hash buckets for dentry cache.
  361. digi= [HW,SERIAL]
  362. IO parameters + enable/disable command.
  363. digiepca= [HW,SERIAL]
  364. See drivers/char/README.epca and
  365. Documentation/digiepca.txt.
  366. dmascc= [HW,AX25,SERIAL] AX.25 Z80SCC driver with DMA
  367. support available.
  368. Format: <io_dev0>[,<io_dev1>[,..<io_dev32>]]
  369. dmasound= [HW,OSS] Sound subsystem buffers
  370. dscc4.setup= [NET]
  371. dtc3181e= [HW,SCSI]
  372. earlyprintk= [IA-32,X86-64]
  373. earlyprintk=vga
  374. earlyprintk=serial[,ttySn[,baudrate]]
  375. Append ",keep" to not disable it when the real console
  376. takes over.
  377. Only vga or serial at a time, not both.
  378. Currently only ttyS0 and ttyS1 are supported.
  379. Interaction with the standard serial driver is not
  380. very good.
  381. The VGA output is eventually overwritten by the real
  382. console.
  383. eata= [HW,SCSI]
  384. ec_intr= [HW,ACPI] ACPI Embedded Controller interrupt mode
  385. Format: <int>
  386. 0: polling mode
  387. non-0: interrupt mode (default)
  388. eda= [HW,PS2]
  389. edb= [HW,PS2]
  390. edd= [EDD]
  391. Format: {"of[f]" | "sk[ipmbr]"}
  392. See comment in arch/i386/boot/edd.S
  393. eicon= [HW,ISDN]
  394. Format: <id>,<membase>,<irq>
  395. eisa_irq_edge= [PARISC,HW]
  396. See header of drivers/parisc/eisa.c.
  397. elanfreq= [IA-32]
  398. See comment before function elanfreq_setup() in
  399. arch/i386/kernel/cpu/cpufreq/elanfreq.c.
  400. elevator= [IOSCHED]
  401. Format: {"anticipatory" | "cfq" | "deadline" | "noop"}
  402. See Documentation/block/as-iosched.txt and
  403. Documentation/block/deadline-iosched.txt for details.
  404. elfcorehdr= [IA-32, X86_64]
  405. Specifies physical address of start of kernel core
  406. image elf header. Generally kexec loader will
  407. pass this option to capture kernel.
  408. See Documentation/kdump/kdump.txt for details.
  409. enforcing [SELINUX] Set initial enforcing status.
  410. Format: {"0" | "1"}
  411. See security/selinux/Kconfig help text.
  412. 0 -- permissive (log only, no denials).
  413. 1 -- enforcing (deny and log).
  414. Default value is 0.
  415. Value can be changed at runtime via /selinux/enforce.
  416. es1371= [HW,OSS]
  417. Format: <spdif>,[<nomix>,[<amplifier>]]
  418. See also header of sound/oss/es1371.c.
  419. ether= [HW,NET] Ethernet cards parameters
  420. This option is obsoleted by the "netdev=" option, which
  421. has equivalent usage. See its documentation for details.
  422. eurwdt= [HW,WDT] Eurotech CPU-1220/1410 onboard watchdog.
  423. Format: <io>[,<irq>]
  424. fd_mcs= [HW,SCSI]
  425. See header of drivers/scsi/fd_mcs.c.
  426. fdomain= [HW,SCSI]
  427. See header of drivers/scsi/fdomain.c.
  428. floppy= [HW]
  429. See Documentation/floppy.txt.
  430. gamecon.map[2|3]=
  431. [HW,JOY] Multisystem joystick and NES/SNES/PSX pad
  432. support via parallel port (up to 5 devices per port)
  433. Format: <port#>,<pad1>,<pad2>,<pad3>,<pad4>,<pad5>
  434. See also Documentation/input/joystick-parport.txt
  435. gamma= [HW,DRM]
  436. gdth= [HW,SCSI]
  437. See header of drivers/scsi/gdth.c.
  438. gpt [EFI] Forces disk with valid GPT signature but
  439. invalid Protective MBR to be treated as GPT.
  440. gscd= [HW,CD]
  441. Format: <io>
  442. gvp11= [HW,SCSI]
  443. hashdist= [KNL,NUMA] Large hashes allocated during boot
  444. are distributed across NUMA nodes. Defaults on
  445. for IA-64, off otherwise.
  446. Format: 0 | 1 (for off | on)
  447. hcl= [IA-64] SGI's Hardware Graph compatibility layer
  448. hd= [EIDE] (E)IDE hard drive subsystem geometry
  449. Format: <cyl>,<head>,<sect>
  450. hd?= [HW] (E)IDE subsystem
  451. hd?lun= See Documentation/ide.txt.
  452. highmem=nn[KMG] [KNL,BOOT] forces the highmem zone to have an exact
  453. size of <nn>. This works even on boxes that have no
  454. highmem otherwise. This also works to reduce highmem
  455. size on bigger boxes.
  456. hisax= [HW,ISDN]
  457. See Documentation/isdn/README.HiSax.
  458. hugepages= [HW,IA-32,IA-64] Maximal number of HugeTLB pages.
  459. noirqbalance [IA-32,SMP,KNL] Disable kernel irq balancing
  460. i8042.direct [HW] Put keyboard port into non-translated mode
  461. i8042.dumbkbd [HW] Pretend that controller can only read data from
  462. keyboard and cannot control its state
  463. (Don't attempt to blink the leds)
  464. i8042.noaux [HW] Don't check for auxiliary (== mouse) port
  465. i8042.nokbd [HW] Don't check/create keyboard port
  466. i8042.nomux [HW] Don't check presence of an active multiplexing
  467. controller
  468. i8042.nopnp [HW] Don't use ACPIPnP / PnPBIOS to discover KBD/AUX
  469. controllers
  470. i8042.panicblink=
  471. [HW] Frequency with which keyboard LEDs should blink
  472. when kernel panics (default is 0.5 sec)
  473. i8042.reset [HW] Reset the controller during init and cleanup
  474. i8042.unlock [HW] Unlock (ignore) the keylock
  475. i810= [HW,DRM]
  476. i8k.ignore_dmi [HW] Continue probing hardware even if DMI data
  477. indicates that the driver is running on unsupported
  478. hardware.
  479. i8k.force [HW] Activate i8k driver even if SMM BIOS signature
  480. does not match list of supported models.
  481. i8k.power_status
  482. [HW] Report power status in /proc/i8k
  483. (disabled by default)
  484. i8k.restricted [HW] Allow controlling fans only if SYS_ADMIN
  485. capability is set.
  486. ibmmcascsi= [HW,MCA,SCSI] IBM MicroChannel SCSI adapter
  487. See Documentation/mca.txt.
  488. icn= [HW,ISDN]
  489. Format: <io>[,<membase>[,<icn_id>[,<icn_id2>]]]
  490. ide= [HW] (E)IDE subsystem
  491. Format: ide=nodma or ide=doubler or ide=reverse
  492. See Documentation/ide.txt.
  493. ide?= [HW] (E)IDE subsystem
  494. Format: ide?=noprobe or chipset specific parameters.
  495. See Documentation/ide.txt.
  496. idebus= [HW] (E)IDE subsystem - VLB/PCI bus speed
  497. See Documentation/ide.txt.
  498. idle= [HW]
  499. Format: idle=poll or idle=halt
  500. ihash_entries= [KNL]
  501. Set number of hash buckets for inode cache.
  502. in2000= [HW,SCSI]
  503. See header of drivers/scsi/in2000.c.
  504. init= [KNL]
  505. Format: <full_path>
  506. Run specified binary instead of /sbin/init as init
  507. process.
  508. initcall_debug [KNL] Trace initcalls as they are executed. Useful
  509. for working out where the kernel is dying during
  510. startup.
  511. initrd= [BOOT] Specify the location of the initial ramdisk
  512. inport.irq= [HW] Inport (ATI XL and Microsoft) busmouse driver
  513. Format: <irq>
  514. combined_mode= [HW] control which driver uses IDE ports in combined
  515. mode: legacy IDE driver, libata, or both
  516. (in the libata case, libata.atapi_enabled=1 may be
  517. useful as well). Note that using the ide or libata
  518. options may affect your device naming (e.g. by
  519. changing hdc to sdb).
  520. Format: combined (default), ide, or libata
  521. inttest= [IA64]
  522. io7= [HW] IO7 for Marvel based alpha systems
  523. See comment before marvel_specify_io7 in
  524. arch/alpha/kernel/core_marvel.c.
  525. ip= [IP_PNP]
  526. See Documentation/nfsroot.txt.
  527. ip2= [HW] Set IO/IRQ pairs for up to 4 IntelliPort boards
  528. See comment before ip2_setup() in drivers/char/ip2.c.
  529. ips= [HW,SCSI] Adaptec / IBM ServeRAID controller
  530. See header of drivers/scsi/ips.c.
  531. ports= [IP_VS_FTP] IPVS ftp helper module
  532. Default is 21.
  533. Up to 8 (IP_VS_APP_MAX_PORTS) ports
  534. may be specified.
  535. Format: <port>,<port>....
  536. irqfixup [HW]
  537. When an interrupt is not handled search all handlers
  538. for it. Intended to get systems with badly broken
  539. firmware running.
  540. irqpoll [HW]
  541. When an interrupt is not handled search all handlers
  542. for it. Also check all handlers each timer
  543. interrupt. Intended to get systems with badly broken
  544. firmware running.
  545. isapnp= [ISAPNP]
  546. Format: <RDP>,<reset>,<pci_scan>,<verbosity>
  547. isolcpus= [KNL,SMP] Isolate CPUs from the general scheduler.
  548. Format:
  549. <cpu number>,...,<cpu number>
  550. or
  551. <cpu number>-<cpu number> (must be a positive range in ascending order)
  552. or a mixture
  553. <cpu number>,...,<cpu number>-<cpu number>
  554. This option can be used to specify one or more CPUs
  555. to isolate from the general SMP balancing and scheduling
  556. algorithms. The only way to move a process onto or off
  557. an "isolated" CPU is via the CPU affinity syscalls.
  558. <cpu number> begins at 0 and the maximum value is
  559. "number of CPUs in system - 1".
  560. This option is the preferred way to isolate CPUs. The
  561. alternative -- manually setting the CPU mask of all
  562. tasks in the system -- can cause problems and
  563. suboptimal load balancer performance.
  564. isp16= [HW,CD]
  565. Format: <io>,<irq>,<dma>,<setup>
  566. iucv= [HW,NET]
  567. js= [HW,JOY] Analog joystick
  568. See Documentation/input/joystick.txt.
  569. keepinitrd [HW,ARM]
  570. kstack=N [IA-32,X86-64] Print N words from the kernel stack
  571. in oops dumps.
  572. l2cr= [PPC]
  573. lapic [IA-32,APIC] Enable the local APIC even if BIOS
  574. disabled it.
  575. lasi= [HW,SCSI] PARISC LASI driver for the 53c700 chip
  576. Format: addr:<io>,irq:<irq>
  577. llsc*= [IA64] See function print_params() in
  578. arch/ia64/sn/kernel/llsc4.c.
  579. load_ramdisk= [RAM] List of ramdisks to load from floppy
  580. See Documentation/ramdisk.txt.
  581. lockd.nlm_grace_period=P [NFS] Assign grace period.
  582. Format: <integer>
  583. lockd.nlm_tcpport=N [NFS] Assign TCP port.
  584. Format: <integer>
  585. lockd.nlm_timeout=T [NFS] Assign timeout value.
  586. Format: <integer>
  587. lockd.nlm_udpport=M [NFS] Assign UDP port.
  588. Format: <integer>
  589. logibm.irq= [HW,MOUSE] Logitech Bus Mouse Driver
  590. Format: <irq>
  591. loglevel= All Kernel Messages with a loglevel smaller than the
  592. console loglevel will be printed to the console. It can
  593. also be changed with klogd or other programs. The
  594. loglevels are defined as follows:
  595. 0 (KERN_EMERG) system is unusable
  596. 1 (KERN_ALERT) action must be taken immediately
  597. 2 (KERN_CRIT) critical conditions
  598. 3 (KERN_ERR) error conditions
  599. 4 (KERN_WARNING) warning conditions
  600. 5 (KERN_NOTICE) normal but significant condition
  601. 6 (KERN_INFO) informational
  602. 7 (KERN_DEBUG) debug-level messages
  603. log_buf_len=n Sets the size of the printk ring buffer, in bytes.
  604. Format: { n | nk | nM }
  605. n must be a power of two. The default size
  606. is set in the kernel config file.
  607. lp=0 [LP] Specify parallel ports to use, e.g,
  608. lp=port[,port...] lp=none,parport0 (lp0 not configured, lp1 uses
  609. lp=reset first parallel port). 'lp=0' disables the
  610. lp=auto printer driver. 'lp=reset' (which can be
  611. specified in addition to the ports) causes
  612. attached printers to be reset. Using
  613. lp=port1,port2,... specifies the parallel ports
  614. to associate lp devices with, starting with
  615. lp0. A port specification may be 'none' to skip
  616. that lp device, or a parport name such as
  617. 'parport0'. Specifying 'lp=auto' instead of a
  618. port specification list means that device IDs
  619. from each port should be examined, to see if
  620. an IEEE 1284-compliant printer is attached; if
  621. so, the driver will manage that printer.
  622. See also header of drivers/char/lp.c.
  623. lpj=n [KNL]
  624. Sets loops_per_jiffy to given constant, thus avoiding
  625. time-consuming boot-time autodetection (up to 250 ms per
  626. CPU). 0 enables autodetection (default). To determine
  627. the correct value for your kernel, boot with normal
  628. autodetection and see what value is printed. Note that
  629. on SMP systems the preset will be applied to all CPUs,
  630. which is likely to cause problems if your CPUs need
  631. significantly divergent settings. An incorrect value
  632. will cause delays in the kernel to be wrong, leading to
  633. unpredictable I/O errors and other breakage. Although
  634. unlikely, in the extreme case this might damage your
  635. hardware.
  636. ltpc= [NET]
  637. Format: <io>,<irq>,<dma>
  638. mac5380= [HW,SCSI] Format:
  639. <can_queue>,<cmd_per_lun>,<sg_tablesize>,<hostid>,<use_tags>
  640. mac53c9x= [HW,SCSI] Format:
  641. <num_esps>,<disconnect>,<nosync>,<can_queue>,<cmd_per_lun>,<sg_tablesize>,<hostid>,<use_tags>
  642. machvec= [IA64] Force the use of a particular machine-vector
  643. (machvec) in a generic kernel.
  644. Example: machvec=hpzx1_swiotlb
  645. max_loop= [LOOP] Maximum number of loopback devices that can
  646. be mounted
  647. Format: <1-256>
  648. maxcpus= [SMP] Maximum number of processors that an SMP kernel
  649. should make use of
  650. max_addr=[KMG] [KNL,BOOT,ia64] All physical memory greater than or
  651. equal to this physical address is ignored.
  652. max_luns= [SCSI] Maximum number of LUNs to probe.
  653. Should be between 1 and 2^32-1.
  654. max_report_luns=
  655. [SCSI] Maximum number of LUNs received.
  656. Should be between 1 and 16384.
  657. mca-pentium [BUGS=IA-32]
  658. mcatest= [IA-64]
  659. mcd= [HW,CD]
  660. Format: <port>,<irq>,<mitsumi_bug_93_wait>
  661. mcdx= [HW,CD]
  662. mce [IA-32] Machine Check Exception
  663. md= [HW] RAID subsystems devices and level
  664. See Documentation/md.txt.
  665. mdacon= [MDA]
  666. Format: <first>,<last>
  667. Specifies range of consoles to be captured by the MDA.
  668. mem=nn[KMG] [KNL,BOOT] Force usage of a specific amount of memory
  669. Amount of memory to be used when the kernel is not able
  670. to see the whole system memory or for test.
  671. [IA-32] Use together with memmap= to avoid physical
  672. address space collisions. Without memmap= PCI devices
  673. could be placed at addresses belonging to unused RAM.
  674. mem=nopentium [BUGS=IA-32] Disable usage of 4MB pages for kernel
  675. memory.
  676. memmap=exactmap [KNL,IA-32,X86_64] Enable setting of an exact
  677. E820 memory map, as specified by the user.
  678. Such memmap=exactmap lines can be constructed based on
  679. BIOS output or other requirements. See the memmap=nn@ss
  680. option description.
  681. memmap=nn[KMG]@ss[KMG]
  682. [KNL] Force usage of a specific region of memory
  683. Region of memory to be used, from ss to ss+nn.
  684. memmap=nn[KMG]#ss[KMG]
  685. [KNL,ACPI] Mark specific memory as ACPI data.
  686. Region of memory to be used, from ss to ss+nn.
  687. memmap=nn[KMG]$ss[KMG]
  688. [KNL,ACPI] Mark specific memory as reserved.
  689. Region of memory to be used, from ss to ss+nn.
  690. meye.*= [HW] Set MotionEye Camera parameters
  691. See Documentation/video4linux/meye.txt.
  692. mga= [HW,DRM]
  693. migration_cost=
  694. [KNL,SMP] debug: override scheduler migration costs
  695. Format: <level-1-usecs>,<level-2-usecs>,...
  696. This debugging option can be used to override the
  697. default scheduler migration cost matrix. The numbers
  698. are indexed by 'CPU domain distance'.
  699. E.g. migration_cost=1000,2000,3000 on an SMT NUMA
  700. box will set up an intra-core migration cost of
  701. 1 msec, an inter-core migration cost of 2 msecs,
  702. and an inter-node migration cost of 3 msecs.
  703. WARNING: using the wrong values here can break
  704. scheduler performance, so it's only for scheduler
  705. development purposes, not production environments.
  706. migration_debug=
  707. [KNL,SMP] migration cost auto-detect verbosity
  708. Format=<0|1|2>
  709. If a system's migration matrix reported at bootup
  710. seems erroneous then this option can be used to
  711. increase verbosity of the detection process.
  712. We default to 0 (no extra messages), 1 will print
  713. some more information, and 2 will be really
  714. verbose (probably only useful if you also have a
  715. serial console attached to the system).
  716. migration_factor=
  717. [KNL,SMP] multiply/divide migration costs by a factor
  718. Format=<percent>
  719. This debug option can be used to proportionally
  720. increase or decrease the auto-detected migration
  721. costs for all entries of the migration matrix.
  722. E.g. migration_factor=150 will increase migration
  723. costs by 50%. (and thus the scheduler will be less
  724. eager migrating cache-hot tasks)
  725. migration_factor=80 will decrease migration costs
  726. by 20%. (thus the scheduler will be more eager to
  727. migrate tasks)
  728. WARNING: using the wrong values here can break
  729. scheduler performance, so it's only for scheduler
  730. development purposes, not production environments.
  731. mousedev.tap_time=
  732. [MOUSE] Maximum time between finger touching and
  733. leaving touchpad surface for touch to be considered
  734. a tap and be reported as a left button click (for
  735. touchpads working in absolute mode only).
  736. Format: <msecs>
  737. mousedev.xres= [MOUSE] Horizontal screen resolution, used for devices
  738. reporting absolute coordinates, such as tablets
  739. mousedev.yres= [MOUSE] Vertical screen resolution, used for devices
  740. reporting absolute coordinates, such as tablets
  741. mpu401= [HW,OSS]
  742. Format: <io>,<irq>
  743. MTD_Partition= [MTD]
  744. Format: <name>,<region-number>,<size>,<offset>
  745. MTD_Region= [MTD] Format:
  746. <name>,<region-number>[,<base>,<size>,<buswidth>,<altbuswidth>]
  747. mtdparts= [MTD]
  748. See drivers/mtd/cmdline.c.
  749. mtouchusb.raw_coordinates=
  750. [HW] Make the MicroTouch USB driver use raw coordinates
  751. ('y', default) or cooked coordinates ('n')
  752. n2= [NET] SDL Inc. RISCom/N2 synchronous serial card
  753. NCR_D700= [HW,SCSI]
  754. See header of drivers/scsi/NCR_D700.c.
  755. ncr5380= [HW,SCSI]
  756. ncr53c400= [HW,SCSI]
  757. ncr53c400a= [HW,SCSI]
  758. ncr53c406a= [HW,SCSI]
  759. ncr53c8xx= [HW,SCSI]
  760. netdev= [NET] Network devices parameters
  761. Format: <irq>,<io>,<mem_start>,<mem_end>,<name>
  762. Note that mem_start is often overloaded to mean
  763. something different and driver-specific.
  764. This usage is only documented in each driver source
  765. file if at all.
  766. nfsaddrs= [NFS]
  767. See Documentation/nfsroot.txt.
  768. nfsroot= [NFS] nfs root filesystem for disk-less boxes.
  769. See Documentation/nfsroot.txt.
  770. nfs.callback_tcpport=
  771. [NFS] set the TCP port on which the NFSv4 callback
  772. channel should listen.
  773. nfs.idmap_cache_timeout=
  774. [NFS] set the maximum lifetime for idmapper cache
  775. entries.
  776. nmi_watchdog= [KNL,BUGS=IA-32] Debugging features for SMP kernels
  777. no387 [BUGS=IA-32] Tells the kernel to use the 387 maths
  778. emulation library even if a 387 maths coprocessor
  779. is present.
  780. noaliencache [MM, NUMA] Disables the allcoation of alien caches in
  781. the slab allocator. Saves per-node memory, but will
  782. impact performance on real NUMA hardware.
  783. noalign [KNL,ARM]
  784. noapic [SMP,APIC] Tells the kernel to not make use of any
  785. IOAPICs that may be present in the system.
  786. noasync [HW,M68K] Disables async and sync negotiation for
  787. all devices.
  788. nobats [PPC] Do not use BATs for mapping kernel lowmem
  789. on "Classic" PPC cores.
  790. nocache [ARM]
  791. nodelayacct [KNL] Disable per-task delay accounting
  792. nodisconnect [HW,SCSI,M68K] Disables SCSI disconnects.
  793. noexec [IA-64]
  794. noexec [IA-32,X86-64]
  795. noexec=on: enable non-executable mappings (default)
  796. noexec=off: disable nn-executable mappings
  797. nofxsr [BUGS=IA-32] Disables x86 floating point extended
  798. register save and restore. The kernel will only save
  799. legacy floating-point registers on task switch.
  800. nohlt [BUGS=ARM]
  801. no-hlt [BUGS=IA-32] Tells the kernel that the hlt
  802. instruction doesn't work correctly and not to
  803. use it.
  804. nohalt [IA-64] Tells the kernel not to use the power saving
  805. function PAL_HALT_LIGHT when idle. This increases
  806. power-consumption. On the positive side, it reduces
  807. interrupt wake-up latency, which may improve performance
  808. in certain environments such as networked servers or
  809. real-time systems.
  810. noirqdebug [IA-32] Disables the code which attempts to detect and
  811. disable unhandled interrupt sources.
  812. noisapnp [ISAPNP] Disables ISA PnP code.
  813. noinitrd [RAM] Tells the kernel not to load any configured
  814. initial RAM disk.
  815. nointroute [IA-64]
  816. nolapic [IA-32,APIC] Do not enable or use the local APIC.
  817. noltlbs [PPC] Do not use large page/tlb entries for kernel
  818. lowmem mapping on PPC40x.
  819. nomca [IA-64] Disable machine check abort handling
  820. nomce [IA-32] Machine Check Exception
  821. noresidual [PPC] Don't use residual data on PReP machines.
  822. noresume [SWSUSP] Disables resume and restores original swap
  823. space.
  824. no-scroll [VGA] Disables scrollback.
  825. This is required for the Braillex ib80-piezo Braille
  826. reader made by F.H. Papenmeier (Germany).
  827. nosbagart [IA-64]
  828. nosep [BUGS=IA-32] Disables x86 SYSENTER/SYSEXIT support.
  829. nosmp [SMP] Tells an SMP kernel to act as a UP kernel.
  830. nosync [HW,M68K] Disables sync negotiation for all devices.
  831. notsc [BUGS=IA-32] Disable Time Stamp Counter
  832. nousb [USB] Disable the USB subsystem
  833. nowb [ARM]
  834. nr_uarts= [SERIAL] maximum number of UARTs to be registered.
  835. opl3= [HW,OSS]
  836. Format: <io>
  837. opl3sa2= [HW,OSS] Format:
  838. <io>,<irq>,<dma>,<dma2>,<mss_io>,<mpu_io>,<ymode>,<loopback>[,<isapnp>,<multiple]
  839. oprofile.timer= [HW]
  840. Use timer interrupt instead of performance counters
  841. optcd= [HW,CD]
  842. Format: <io>
  843. osst= [HW,SCSI] SCSI Tape Driver
  844. Format: <buffer_size>,<write_threshold>
  845. See also Documentation/scsi/st.txt.
  846. panic= [KNL] Kernel behaviour on panic
  847. Format: <timeout>
  848. parkbd.port= [HW] Parallel port number the keyboard adapter is
  849. connected to, default is 0.
  850. Format: <parport#>
  851. parkbd.mode= [HW] Parallel port keyboard adapter mode of operation,
  852. 0 for XT, 1 for AT (default is AT).
  853. Format: <mode>
  854. parport= [HW,PPT] Specify parallel ports. 0 disables.
  855. Format: { 0 | auto | 0xBBB[,IRQ[,DMA]] }
  856. Use 'auto' to force the driver to use any
  857. IRQ/DMA settings detected (the default is to
  858. ignore detected IRQ/DMA settings because of
  859. possible conflicts). You can specify the base
  860. address, IRQ, and DMA settings; IRQ and DMA
  861. should be numbers, or 'auto' (for using detected
  862. settings on that particular port), or 'nofifo'
  863. (to avoid using a FIFO even if it is detected).
  864. Parallel ports are assigned in the order they
  865. are specified on the command line, starting
  866. with parport0.
  867. parport_init_mode= [HW,PPT]
  868. Configure VIA parallel port to operate in
  869. a specific mode. This is necessary on Pegasos
  870. computer where firmware has no options for setting
  871. up parallel port mode and sets it to spp.
  872. Currently this function knows 686a and 8231 chips.
  873. Format: [spp|ps2|epp|ecp|ecpepp]
  874. pas2= [HW,OSS] Format:
  875. <io>,<irq>,<dma>,<dma16>,<sb_io>,<sb_irq>,<sb_dma>,<sb_dma16>
  876. pas16= [HW,SCSI]
  877. See header of drivers/scsi/pas16.c.
  878. pause_on_oops=
  879. Halt all CPUs after the first oops has been printed for
  880. the specified number of seconds. This is to be used if
  881. your oopses keep scrolling off the screen.
  882. pcbit= [HW,ISDN]
  883. pcd. [PARIDE]
  884. See header of drivers/block/paride/pcd.c.
  885. See also Documentation/paride.txt.
  886. pci=option[,option...] [PCI] various PCI subsystem options:
  887. off [IA-32] don't probe for the PCI bus
  888. bios [IA-32] force use of PCI BIOS, don't access
  889. the hardware directly. Use this if your machine
  890. has a non-standard PCI host bridge.
  891. nobios [IA-32] disallow use of PCI BIOS, only direct
  892. hardware access methods are allowed. Use this
  893. if you experience crashes upon bootup and you
  894. suspect they are caused by the BIOS.
  895. conf1 [IA-32] Force use of PCI Configuration
  896. Mechanism 1.
  897. conf2 [IA-32] Force use of PCI Configuration
  898. Mechanism 2.
  899. nommconf [IA-32,X86_64] Disable use of MMCONFIG for PCI
  900. Configuration
  901. nomsi [MSI] If the PCI_MSI kernel config parameter is
  902. enabled, this kernel boot option can be used to
  903. disable the use of MSI interrupts system-wide.
  904. nosort [IA-32] Don't sort PCI devices according to
  905. order given by the PCI BIOS. This sorting is
  906. done to get a device order compatible with
  907. older kernels.
  908. biosirq [IA-32] Use PCI BIOS calls to get the interrupt
  909. routing table. These calls are known to be buggy
  910. on several machines and they hang the machine
  911. when used, but on other computers it's the only
  912. way to get the interrupt routing table. Try
  913. this option if the kernel is unable to allocate
  914. IRQs or discover secondary PCI buses on your
  915. motherboard.
  916. rom [IA-32] Assign address space to expansion ROMs.
  917. Use with caution as certain devices share
  918. address decoders between ROMs and other
  919. resources.
  920. irqmask=0xMMMM [IA-32] Set a bit mask of IRQs allowed to be
  921. assigned automatically to PCI devices. You can
  922. make the kernel exclude IRQs of your ISA cards
  923. this way.
  924. pirqaddr=0xAAAAA [IA-32] Specify the physical address
  925. of the PIRQ table (normally generated
  926. by the BIOS) if it is outside the
  927. F0000h-100000h range.
  928. lastbus=N [IA-32] Scan all buses thru bus #N. Can be
  929. useful if the kernel is unable to find your
  930. secondary buses and you want to tell it
  931. explicitly which ones they are.
  932. assign-busses [IA-32] Always assign all PCI bus
  933. numbers ourselves, overriding
  934. whatever the firmware may have done.
  935. usepirqmask [IA-32] Honor the possible IRQ mask stored
  936. in the BIOS $PIR table. This is needed on
  937. some systems with broken BIOSes, notably
  938. some HP Pavilion N5400 and Omnibook XE3
  939. notebooks. This will have no effect if ACPI
  940. IRQ routing is enabled.
  941. noacpi [IA-32] Do not use ACPI for IRQ routing
  942. or for PCI scanning.
  943. routeirq Do IRQ routing for all PCI devices.
  944. This is normally done in pci_enable_device(),
  945. so this option is a temporary workaround
  946. for broken drivers that don't call it.
  947. firmware [ARM] Do not re-enumerate the bus but instead
  948. just use the configuration from the
  949. bootloader. This is currently used on
  950. IXP2000 systems where the bus has to be
  951. configured a certain way for adjunct CPUs.
  952. noearly [X86] Don't do any early type 1 scanning.
  953. This might help on some broken boards which
  954. machine check when some devices' config space
  955. is read. But various workarounds are disabled
  956. and some IOMMU drivers will not work.
  957. bfsort Sort PCI devices into breadth-first order.
  958. This sorting is done to get a device
  959. order compatible with older (<= 2.4) kernels.
  960. nobfsort Don't sort PCI devices into breadth-first order.
  961. pcmv= [HW,PCMCIA] BadgePAD 4
  962. pd. [PARIDE]
  963. See Documentation/paride.txt.
  964. pdcchassis= [PARISC,HW] Disable/Enable PDC Chassis Status codes at
  965. boot time.
  966. Format: { 0 | 1 }
  967. See arch/parisc/kernel/pdc_chassis.c
  968. pf. [PARIDE]
  969. See Documentation/paride.txt.
  970. pg. [PARIDE]
  971. See Documentation/paride.txt.
  972. pirq= [SMP,APIC] Manual mp-table setup
  973. See Documentation/i386/IO-APIC.txt.
  974. plip= [PPT,NET] Parallel port network link
  975. Format: { parport<nr> | timid | 0 }
  976. See also Documentation/parport.txt.
  977. pnpacpi= [ACPI]
  978. { off }
  979. pnpbios= [ISAPNP]
  980. { on | off | curr | res | no-curr | no-res }
  981. pnp_reserve_irq=
  982. [ISAPNP] Exclude IRQs for the autoconfiguration
  983. pnp_reserve_dma=
  984. [ISAPNP] Exclude DMAs for the autoconfiguration
  985. pnp_reserve_io= [ISAPNP] Exclude I/O ports for the autoconfiguration
  986. Ranges are in pairs (I/O port base and size).
  987. pnp_reserve_mem=
  988. [ISAPNP] Exclude memory regions for the
  989. autoconfiguration.
  990. Ranges are in pairs (memory base and size).
  991. profile= [KNL] Enable kernel profiling via /proc/profile
  992. Format: [schedule,]<number>
  993. Param: "schedule" - profile schedule points.
  994. Param: <number> - step/bucket size as a power of 2 for
  995. statistical time based profiling.
  996. processor.max_cstate= [HW,ACPI]
  997. Limit processor to maximum C-state
  998. max_cstate=9 overrides any DMI blacklist limit.
  999. processor.nocst [HW,ACPI]
  1000. Ignore the _CST method to determine C-states,
  1001. instead using the legacy FADT method
  1002. prompt_ramdisk= [RAM] List of RAM disks to prompt for floppy disk
  1003. before loading.
  1004. See Documentation/ramdisk.txt.
  1005. psmouse.proto= [HW,MOUSE] Highest PS2 mouse protocol extension to
  1006. probe for; one of (bare|imps|exps|lifebook|any).
  1007. psmouse.rate= [HW,MOUSE] Set desired mouse report rate, in reports
  1008. per second.
  1009. psmouse.resetafter= [HW,MOUSE]
  1010. Try to reset the device after so many bad packets
  1011. (0 = never).
  1012. psmouse.resolution=
  1013. [HW,MOUSE] Set desired mouse resolution, in dpi.
  1014. psmouse.smartscroll=
  1015. [HW,MOUSE] Controls Logitech smartscroll autorepeat.
  1016. 0 = disabled, 1 = enabled (default).
  1017. pss= [HW,OSS] Personal Sound System (ECHO ESC614)
  1018. Format:
  1019. <io>,<mss_io>,<mss_irq>,<mss_dma>,<mpu_io>,<mpu_irq>
  1020. pt. [PARIDE]
  1021. See Documentation/paride.txt.
  1022. quiet [KNL] Disable most log messages
  1023. r128= [HW,DRM]
  1024. raid= [HW,RAID]
  1025. See Documentation/md.txt.
  1026. ramdisk= [RAM] Sizes of RAM disks in kilobytes [deprecated]
  1027. See Documentation/ramdisk.txt.
  1028. ramdisk_blocksize= [RAM]
  1029. See Documentation/ramdisk.txt.
  1030. ramdisk_size= [RAM] Sizes of RAM disks in kilobytes
  1031. New name for the ramdisk parameter.
  1032. See Documentation/ramdisk.txt.
  1033. rcu.blimit= [KNL,BOOT] Set maximum number of finished
  1034. RCU callbacks to process in one batch.
  1035. rcu.qhimark= [KNL,BOOT] Set threshold of queued
  1036. RCU callbacks over which batch limiting is disabled.
  1037. rcu.qlowmark= [KNL,BOOT] Set threshold of queued
  1038. RCU callbacks below which batch limiting is re-enabled.
  1039. rdinit= [KNL]
  1040. Format: <full_path>
  1041. Run specified binary instead of /init from the ramdisk,
  1042. used for early userspace startup. See initrd.
  1043. reboot= [BUGS=IA-32,BUGS=ARM,BUGS=IA-64] Rebooting mode
  1044. Format: <reboot_mode>[,<reboot_mode2>[,...]]
  1045. See arch/*/kernel/reboot.c or arch/*/kernel/process.c
  1046. reserve= [KNL,BUGS] Force the kernel to ignore some iomem area
  1047. reservetop= [IA-32]
  1048. Format: nn[KMG]
  1049. Reserves a hole at the top of the kernel virtual
  1050. address space.
  1051. reset_devices [KNL] Force drivers to reset the underlying device
  1052. during initialization.
  1053. resume= [SWSUSP]
  1054. Specify the partition device for software suspend
  1055. resume_offset= [SWSUSP]
  1056. Specify the offset from the beginning of the partition
  1057. given by "resume=" at which the swap header is located,
  1058. in <PAGE_SIZE> units (needed only for swap files).
  1059. See Documentation/power/swsusp-and-swap-files.txt
  1060. rhash_entries= [KNL,NET]
  1061. Set number of hash buckets for route cache
  1062. riscom8= [HW,SERIAL]
  1063. Format: <io_board1>[,<io_board2>[,...<io_boardN>]]
  1064. ro [KNL] Mount root device read-only on boot
  1065. root= [KNL] Root filesystem
  1066. rootdelay= [KNL] Delay (in seconds) to pause before attempting to
  1067. mount the root filesystem
  1068. rootflags= [KNL] Set root filesystem mount option string
  1069. rootfstype= [KNL] Set root filesystem type
  1070. rw [KNL] Mount root device read-write on boot
  1071. S [KNL] Run init in single mode
  1072. sa1100ir [NET]
  1073. See drivers/net/irda/sa1100_ir.c.
  1074. sb= [HW,OSS]
  1075. Format: <io>,<irq>,<dma>,<dma2>
  1076. sbni= [NET] Granch SBNI12 leased line adapter
  1077. sbpcd= [HW,CD] Soundblaster CD adapter
  1078. Format: <io>,<type>
  1079. See a comment before function sbpcd_setup() in
  1080. drivers/cdrom/sbpcd.c.
  1081. sc1200wdt= [HW,WDT] SC1200 WDT (watchdog) driver
  1082. Format: <io>[,<timeout>[,<isapnp>]]
  1083. scsi_debug_*= [SCSI]
  1084. See drivers/scsi/scsi_debug.c.
  1085. scsi_default_dev_flags=
  1086. [SCSI] SCSI default device flags
  1087. Format: <integer>
  1088. scsi_dev_flags= [SCSI] Black/white list entry for vendor and model
  1089. Format: <vendor>:<model>:<flags>
  1090. (flags are integer value)
  1091. scsi_logging= [SCSI]
  1092. scsi_mod.scan= [SCSI] sync (default) scans SCSI busses as they are
  1093. discovered. async scans them in kernel threads,
  1094. allowing boot to proceed. none ignores them, expecting
  1095. user space to do the scan.
  1096. selinux [SELINUX] Disable or enable SELinux at boot time.
  1097. Format: { "0" | "1" }
  1098. See security/selinux/Kconfig help text.
  1099. 0 -- disable.
  1100. 1 -- enable.
  1101. Default value is set via kernel config option.
  1102. If enabled at boot time, /selinux/disable can be used
  1103. later to disable prior to initial policy load.
  1104. selinux_compat_net =
  1105. [SELINUX] Set initial selinux_compat_net flag value.
  1106. Format: { "0" | "1" }
  1107. 0 -- use new secmark-based packet controls
  1108. 1 -- use legacy packet controls
  1109. Default value is 0 (preferred).
  1110. Value can be changed at runtime via
  1111. /selinux/compat_net.
  1112. serialnumber [BUGS=IA-32]
  1113. sg_def_reserved_size= [SCSI]
  1114. shapers= [NET]
  1115. Maximal number of shapers.
  1116. sim710= [SCSI,HW]
  1117. See header of drivers/scsi/sim710.c.
  1118. simeth= [IA-64]
  1119. simscsi=
  1120. sjcd= [HW,CD]
  1121. Format: <io>,<irq>,<dma>
  1122. See header of drivers/cdrom/sjcd.c.
  1123. slram= [HW,MTD]
  1124. smart2= [HW]
  1125. Format: <io1>[,<io2>[,...,<io8>]]
  1126. snd-ad1816a= [HW,ALSA]
  1127. snd-ad1848= [HW,ALSA]
  1128. snd-ali5451= [HW,ALSA]
  1129. snd-als100= [HW,ALSA]
  1130. snd-als4000= [HW,ALSA]
  1131. snd-azt2320= [HW,ALSA]
  1132. snd-cmi8330= [HW,ALSA]
  1133. snd-cmipci= [HW,ALSA]
  1134. snd-cs4231= [HW,ALSA]
  1135. snd-cs4232= [HW,ALSA]
  1136. snd-cs4236= [HW,ALSA]
  1137. snd-cs4281= [HW,ALSA]
  1138. snd-cs46xx= [HW,ALSA]
  1139. snd-dt019x= [HW,ALSA]
  1140. snd-dummy= [HW,ALSA]
  1141. snd-emu10k1= [HW,ALSA]
  1142. snd-ens1370= [HW,ALSA]
  1143. snd-ens1371= [HW,ALSA]
  1144. snd-es968= [HW,ALSA]
  1145. snd-es1688= [HW,ALSA]
  1146. snd-es18xx= [HW,ALSA]
  1147. snd-es1938= [HW,ALSA]
  1148. snd-es1968= [HW,ALSA]
  1149. snd-fm801= [HW,ALSA]
  1150. snd-gusclassic= [HW,ALSA]
  1151. snd-gusextreme= [HW,ALSA]
  1152. snd-gusmax= [HW,ALSA]
  1153. snd-hdsp= [HW,ALSA]
  1154. snd-ice1712= [HW,ALSA]
  1155. snd-intel8x0= [HW,ALSA]
  1156. snd-interwave= [HW,ALSA]
  1157. snd-interwave-stb=
  1158. [HW,ALSA]
  1159. snd-korg1212= [HW,ALSA]
  1160. snd-maestro3= [HW,ALSA]
  1161. snd-mpu401= [HW,ALSA]
  1162. snd-mtpav= [HW,ALSA]
  1163. snd-nm256= [HW,ALSA]
  1164. snd-opl3sa2= [HW,ALSA]
  1165. snd-opti92x-ad1848=
  1166. [HW,ALSA]
  1167. snd-opti92x-cs4231=
  1168. [HW,ALSA]
  1169. snd-opti93x= [HW,ALSA]
  1170. snd-pmac= [HW,ALSA]
  1171. snd-rme32= [HW,ALSA]
  1172. snd-rme96= [HW,ALSA]
  1173. snd-rme9652= [HW,ALSA]
  1174. snd-sb8= [HW,ALSA]
  1175. snd-sb16= [HW,ALSA]
  1176. snd-sbawe= [HW,ALSA]
  1177. snd-serial= [HW,ALSA]
  1178. snd-sgalaxy= [HW,ALSA]
  1179. snd-sonicvibes= [HW,ALSA]
  1180. snd-sun-amd7930=
  1181. [HW,ALSA]
  1182. snd-sun-cs4231= [HW,ALSA]
  1183. snd-trident= [HW,ALSA]
  1184. snd-usb-audio= [HW,ALSA,USB]
  1185. snd-via82xx= [HW,ALSA]
  1186. snd-virmidi= [HW,ALSA]
  1187. snd-wavefront= [HW,ALSA]
  1188. snd-ymfpci= [HW,ALSA]
  1189. sonycd535= [HW,CD]
  1190. Format: <io>[,<irq>]
  1191. sonypi.*= [HW] Sony Programmable I/O Control Device driver
  1192. See Documentation/sonypi.txt
  1193. specialix= [HW,SERIAL] Specialix multi-serial port adapter
  1194. See Documentation/specialix.txt.
  1195. spia_io_base= [HW,MTD]
  1196. spia_fio_base=
  1197. spia_pedr=
  1198. spia_peddr=
  1199. sscape= [HW,OSS]
  1200. Format: <io>,<irq>,<dma>,<mpu_io>,<mpu_irq>
  1201. st= [HW,SCSI] SCSI tape parameters (buffers, etc.)
  1202. See Documentation/scsi/st.txt.
  1203. st0x= [HW,SCSI]
  1204. See header of drivers/scsi/seagate.c.
  1205. sti= [PARISC,HW]
  1206. Format: <num>
  1207. Set the STI (builtin display/keyboard on the HP-PARISC
  1208. machines) console (graphic card) which should be used
  1209. as the initial boot-console.
  1210. See also comment in drivers/video/console/sticore.c.
  1211. sti_font= [HW]
  1212. See comment in drivers/video/console/sticore.c.
  1213. stifb= [HW]
  1214. Format: bpp:<bpp1>[:<bpp2>[:<bpp3>...]]
  1215. swiotlb= [IA-64] Number of I/O TLB slabs
  1216. switches= [HW,M68k]
  1217. sym53c416= [HW,SCSI]
  1218. See header of drivers/scsi/sym53c416.c.
  1219. t128= [HW,SCSI]
  1220. See header of drivers/scsi/t128.c.
  1221. tdfx= [HW,DRM]
  1222. thash_entries= [KNL,NET]
  1223. Set number of hash buckets for TCP connection
  1224. time Show timing data prefixed to each printk message line
  1225. clocksource= [GENERIC_TIME] Override the default clocksource
  1226. Override the default clocksource and use the clocksource
  1227. with the name specified.
  1228. tipar.timeout= [HW,PPT]
  1229. Set communications timeout in tenths of a second
  1230. (default 15).
  1231. tipar.delay= [HW,PPT]
  1232. Set inter-bit delay in microseconds (default 10).
  1233. tmc8xx= [HW,SCSI]
  1234. See header of drivers/scsi/seagate.c.
  1235. tmscsim= [HW,SCSI]
  1236. See comment before function dc390_setup() in
  1237. drivers/scsi/tmscsim.c.
  1238. tp720= [HW,PS2]
  1239. trix= [HW,OSS] MediaTrix AudioTrix Pro
  1240. Format:
  1241. <io>,<irq>,<dma>,<dma2>,<sb_io>,<sb_irq>,<sb_dma>,<mpu_io>,<mpu_irq>
  1242. tsdev.xres= [TS] Horizontal screen resolution.
  1243. tsdev.yres= [TS] Vertical screen resolution.
  1244. turbografx.map[2|3]= [HW,JOY]
  1245. TurboGraFX parallel port interface
  1246. Format:
  1247. <port#>,<js1>,<js2>,<js3>,<js4>,<js5>,<js6>,<js7>
  1248. See also Documentation/input/joystick-parport.txt
  1249. u14-34f= [HW,SCSI] UltraStor 14F/34F SCSI host adapter
  1250. See header of drivers/scsi/u14-34f.c.
  1251. uart401= [HW,OSS]
  1252. Format: <io>,<irq>
  1253. uart6850= [HW,OSS]
  1254. Format: <io>,<irq>
  1255. usbhid.mousepoll=
  1256. [USBHID] The interval which mice are to be polled at.
  1257. vdso= [IA-32]
  1258. vdso=1: enable VDSO (default)
  1259. vdso=0: disable VDSO mapping
  1260. video= [FB] Frame buffer configuration
  1261. See Documentation/fb/modedb.txt.
  1262. vga= [BOOT,IA-32] Select a particular video mode
  1263. See Documentation/i386/boot.txt and
  1264. Documentation/svga.txt.
  1265. Use vga=ask for menu.
  1266. This is actually a boot loader parameter; the value is
  1267. passed to the kernel using a special protocol.
  1268. vmalloc=nn[KMG] [KNL,BOOT] Forces the vmalloc area to have an exact
  1269. size of <nn>. This can be used to increase the
  1270. minimum size (128MB on x86). It can also be used to
  1271. decrease the size and leave more room for directly
  1272. mapped kernel RAM.
  1273. vmhalt= [KNL,S390] Perform z/VM CP command after system halt.
  1274. Format: <command>
  1275. vmpanic= [KNL,S390] Perform z/VM CP command after kernel panic.
  1276. Format: <command>
  1277. vmpoff= [KNL,S390] Perform z/VM CP command after power off.
  1278. Format: <command>
  1279. waveartist= [HW,OSS]
  1280. Format: <io>,<irq>,<dma>,<dma2>
  1281. wd33c93= [HW,SCSI]
  1282. See header of drivers/scsi/wd33c93.c.
  1283. wd7000= [HW,SCSI]
  1284. See header of drivers/scsi/wd7000.c.
  1285. wdt= [WDT] Watchdog
  1286. See Documentation/watchdog/watchdog.txt.
  1287. xd= [HW,XT] Original XT pre-IDE (RLL encoded) disks.
  1288. xd_geo= See header of drivers/block/xd.c.
  1289. xirc2ps_cs= [NET,PCMCIA]
  1290. Format:
  1291. <irq>,<irq_mask>,<io>,<full_duplex>,<do_sound>,<lockup_hack>[,<irq2>[,<irq3>[,<irq4>]]]
  1292. norandmaps Don't use address space randomization
  1293. Equivalent to echo 0 > /proc/sys/kernel/randomize_va_space
  1294. ______________________________________________________________________
  1295. TODO:
  1296. Add documentation for ALSA options.
  1297. Add more DRM drivers.