kernel-parameters.txt 52 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. failslab=
  425. fail_page_alloc=
  426. fail_make_request=[KNL]
  427. General fault injection mechanism.
  428. Format: <interval>,<probability>,<space>,<times>
  429. See also /Documentation/fault-injection/.
  430. fd_mcs= [HW,SCSI]
  431. See header of drivers/scsi/fd_mcs.c.
  432. fdomain= [HW,SCSI]
  433. See header of drivers/scsi/fdomain.c.
  434. floppy= [HW]
  435. See Documentation/floppy.txt.
  436. gamecon.map[2|3]=
  437. [HW,JOY] Multisystem joystick and NES/SNES/PSX pad
  438. support via parallel port (up to 5 devices per port)
  439. Format: <port#>,<pad1>,<pad2>,<pad3>,<pad4>,<pad5>
  440. See also Documentation/input/joystick-parport.txt
  441. gamma= [HW,DRM]
  442. gdth= [HW,SCSI]
  443. See header of drivers/scsi/gdth.c.
  444. gpt [EFI] Forces disk with valid GPT signature but
  445. invalid Protective MBR to be treated as GPT.
  446. gscd= [HW,CD]
  447. Format: <io>
  448. gvp11= [HW,SCSI]
  449. hashdist= [KNL,NUMA] Large hashes allocated during boot
  450. are distributed across NUMA nodes. Defaults on
  451. for IA-64, off otherwise.
  452. Format: 0 | 1 (for off | on)
  453. hcl= [IA-64] SGI's Hardware Graph compatibility layer
  454. hd= [EIDE] (E)IDE hard drive subsystem geometry
  455. Format: <cyl>,<head>,<sect>
  456. hd?= [HW] (E)IDE subsystem
  457. hd?lun= See Documentation/ide.txt.
  458. highmem=nn[KMG] [KNL,BOOT] forces the highmem zone to have an exact
  459. size of <nn>. This works even on boxes that have no
  460. highmem otherwise. This also works to reduce highmem
  461. size on bigger boxes.
  462. hisax= [HW,ISDN]
  463. See Documentation/isdn/README.HiSax.
  464. hugepages= [HW,IA-32,IA-64] Maximal number of HugeTLB pages.
  465. i8042.direct [HW] Put keyboard port into non-translated mode
  466. i8042.dumbkbd [HW] Pretend that controller can only read data from
  467. keyboard and cannot control its state
  468. (Don't attempt to blink the leds)
  469. i8042.noaux [HW] Don't check for auxiliary (== mouse) port
  470. i8042.nokbd [HW] Don't check/create keyboard port
  471. i8042.nomux [HW] Don't check presence of an active multiplexing
  472. controller
  473. i8042.nopnp [HW] Don't use ACPIPnP / PnPBIOS to discover KBD/AUX
  474. controllers
  475. i8042.panicblink=
  476. [HW] Frequency with which keyboard LEDs should blink
  477. when kernel panics (default is 0.5 sec)
  478. i8042.reset [HW] Reset the controller during init and cleanup
  479. i8042.unlock [HW] Unlock (ignore) the keylock
  480. i810= [HW,DRM]
  481. i8k.ignore_dmi [HW] Continue probing hardware even if DMI data
  482. indicates that the driver is running on unsupported
  483. hardware.
  484. i8k.force [HW] Activate i8k driver even if SMM BIOS signature
  485. does not match list of supported models.
  486. i8k.power_status
  487. [HW] Report power status in /proc/i8k
  488. (disabled by default)
  489. i8k.restricted [HW] Allow controlling fans only if SYS_ADMIN
  490. capability is set.
  491. ibmmcascsi= [HW,MCA,SCSI] IBM MicroChannel SCSI adapter
  492. See Documentation/mca.txt.
  493. icn= [HW,ISDN]
  494. Format: <io>[,<membase>[,<icn_id>[,<icn_id2>]]]
  495. ide= [HW] (E)IDE subsystem
  496. Format: ide=nodma or ide=doubler or ide=reverse
  497. See Documentation/ide.txt.
  498. ide?= [HW] (E)IDE subsystem
  499. Format: ide?=noprobe or chipset specific parameters.
  500. See Documentation/ide.txt.
  501. idebus= [HW] (E)IDE subsystem - VLB/PCI bus speed
  502. See Documentation/ide.txt.
  503. idle= [HW]
  504. Format: idle=poll or idle=halt
  505. ignore_loglevel [KNL]
  506. Ignore loglevel setting - this will print /all/
  507. kernel messages to the console. Useful for debugging.
  508. ihash_entries= [KNL]
  509. Set number of hash buckets for inode cache.
  510. in2000= [HW,SCSI]
  511. See header of drivers/scsi/in2000.c.
  512. init= [KNL]
  513. Format: <full_path>
  514. Run specified binary instead of /sbin/init as init
  515. process.
  516. initcall_debug [KNL] Trace initcalls as they are executed. Useful
  517. for working out where the kernel is dying during
  518. startup.
  519. initrd= [BOOT] Specify the location of the initial ramdisk
  520. inport.irq= [HW] Inport (ATI XL and Microsoft) busmouse driver
  521. Format: <irq>
  522. combined_mode= [HW] control which driver uses IDE ports in combined
  523. mode: legacy IDE driver, libata, or both
  524. (in the libata case, libata.atapi_enabled=1 may be
  525. useful as well). Note that using the ide or libata
  526. options may affect your device naming (e.g. by
  527. changing hdc to sdb).
  528. Format: combined (default), ide, or libata
  529. inttest= [IA64]
  530. io7= [HW] IO7 for Marvel based alpha systems
  531. See comment before marvel_specify_io7 in
  532. arch/alpha/kernel/core_marvel.c.
  533. ip= [IP_PNP]
  534. See Documentation/nfsroot.txt.
  535. ip2= [HW] Set IO/IRQ pairs for up to 4 IntelliPort boards
  536. See comment before ip2_setup() in drivers/char/ip2.c.
  537. ips= [HW,SCSI] Adaptec / IBM ServeRAID controller
  538. See header of drivers/scsi/ips.c.
  539. ports= [IP_VS_FTP] IPVS ftp helper module
  540. Default is 21.
  541. Up to 8 (IP_VS_APP_MAX_PORTS) ports
  542. may be specified.
  543. Format: <port>,<port>....
  544. irqfixup [HW]
  545. When an interrupt is not handled search all handlers
  546. for it. Intended to get systems with badly broken
  547. firmware running.
  548. irqpoll [HW]
  549. When an interrupt is not handled search all handlers
  550. for it. Also check all handlers each timer
  551. interrupt. Intended to get systems with badly broken
  552. firmware running.
  553. isapnp= [ISAPNP]
  554. Format: <RDP>,<reset>,<pci_scan>,<verbosity>
  555. isolcpus= [KNL,SMP] Isolate CPUs from the general scheduler.
  556. Format:
  557. <cpu number>,...,<cpu number>
  558. or
  559. <cpu number>-<cpu number> (must be a positive range in ascending order)
  560. or a mixture
  561. <cpu number>,...,<cpu number>-<cpu number>
  562. This option can be used to specify one or more CPUs
  563. to isolate from the general SMP balancing and scheduling
  564. algorithms. The only way to move a process onto or off
  565. an "isolated" CPU is via the CPU affinity syscalls.
  566. <cpu number> begins at 0 and the maximum value is
  567. "number of CPUs in system - 1".
  568. This option is the preferred way to isolate CPUs. The
  569. alternative -- manually setting the CPU mask of all
  570. tasks in the system -- can cause problems and
  571. suboptimal load balancer performance.
  572. isp16= [HW,CD]
  573. Format: <io>,<irq>,<dma>,<setup>
  574. iucv= [HW,NET]
  575. js= [HW,JOY] Analog joystick
  576. See Documentation/input/joystick.txt.
  577. keepinitrd [HW,ARM]
  578. kstack=N [IA-32,X86-64] Print N words from the kernel stack
  579. in oops dumps.
  580. l2cr= [PPC]
  581. lapic [IA-32,APIC] Enable the local APIC even if BIOS
  582. disabled it.
  583. lasi= [HW,SCSI] PARISC LASI driver for the 53c700 chip
  584. Format: addr:<io>,irq:<irq>
  585. llsc*= [IA64] See function print_params() in
  586. arch/ia64/sn/kernel/llsc4.c.
  587. load_ramdisk= [RAM] List of ramdisks to load from floppy
  588. See Documentation/ramdisk.txt.
  589. lockd.nlm_grace_period=P [NFS] Assign grace period.
  590. Format: <integer>
  591. lockd.nlm_tcpport=N [NFS] Assign TCP port.
  592. Format: <integer>
  593. lockd.nlm_timeout=T [NFS] Assign timeout value.
  594. Format: <integer>
  595. lockd.nlm_udpport=M [NFS] Assign UDP port.
  596. Format: <integer>
  597. logibm.irq= [HW,MOUSE] Logitech Bus Mouse Driver
  598. Format: <irq>
  599. loglevel= All Kernel Messages with a loglevel smaller than the
  600. console loglevel will be printed to the console. It can
  601. also be changed with klogd or other programs. The
  602. loglevels are defined as follows:
  603. 0 (KERN_EMERG) system is unusable
  604. 1 (KERN_ALERT) action must be taken immediately
  605. 2 (KERN_CRIT) critical conditions
  606. 3 (KERN_ERR) error conditions
  607. 4 (KERN_WARNING) warning conditions
  608. 5 (KERN_NOTICE) normal but significant condition
  609. 6 (KERN_INFO) informational
  610. 7 (KERN_DEBUG) debug-level messages
  611. log_buf_len=n Sets the size of the printk ring buffer, in bytes.
  612. Format: { n | nk | nM }
  613. n must be a power of two. The default size
  614. is set in the kernel config file.
  615. lp=0 [LP] Specify parallel ports to use, e.g,
  616. lp=port[,port...] lp=none,parport0 (lp0 not configured, lp1 uses
  617. lp=reset first parallel port). 'lp=0' disables the
  618. lp=auto printer driver. 'lp=reset' (which can be
  619. specified in addition to the ports) causes
  620. attached printers to be reset. Using
  621. lp=port1,port2,... specifies the parallel ports
  622. to associate lp devices with, starting with
  623. lp0. A port specification may be 'none' to skip
  624. that lp device, or a parport name such as
  625. 'parport0'. Specifying 'lp=auto' instead of a
  626. port specification list means that device IDs
  627. from each port should be examined, to see if
  628. an IEEE 1284-compliant printer is attached; if
  629. so, the driver will manage that printer.
  630. See also header of drivers/char/lp.c.
  631. lpj=n [KNL]
  632. Sets loops_per_jiffy to given constant, thus avoiding
  633. time-consuming boot-time autodetection (up to 250 ms per
  634. CPU). 0 enables autodetection (default). To determine
  635. the correct value for your kernel, boot with normal
  636. autodetection and see what value is printed. Note that
  637. on SMP systems the preset will be applied to all CPUs,
  638. which is likely to cause problems if your CPUs need
  639. significantly divergent settings. An incorrect value
  640. will cause delays in the kernel to be wrong, leading to
  641. unpredictable I/O errors and other breakage. Although
  642. unlikely, in the extreme case this might damage your
  643. hardware.
  644. ltpc= [NET]
  645. Format: <io>,<irq>,<dma>
  646. mac5380= [HW,SCSI] Format:
  647. <can_queue>,<cmd_per_lun>,<sg_tablesize>,<hostid>,<use_tags>
  648. mac53c9x= [HW,SCSI] Format:
  649. <num_esps>,<disconnect>,<nosync>,<can_queue>,<cmd_per_lun>,<sg_tablesize>,<hostid>,<use_tags>
  650. machvec= [IA64] Force the use of a particular machine-vector
  651. (machvec) in a generic kernel.
  652. Example: machvec=hpzx1_swiotlb
  653. max_loop= [LOOP] Maximum number of loopback devices that can
  654. be mounted
  655. Format: <1-256>
  656. maxcpus= [SMP] Maximum number of processors that an SMP kernel
  657. should make use of
  658. max_addr=[KMG] [KNL,BOOT,ia64] All physical memory greater than or
  659. equal to this physical address is ignored.
  660. max_luns= [SCSI] Maximum number of LUNs to probe.
  661. Should be between 1 and 2^32-1.
  662. max_report_luns=
  663. [SCSI] Maximum number of LUNs received.
  664. Should be between 1 and 16384.
  665. mca-pentium [BUGS=IA-32]
  666. mcatest= [IA-64]
  667. mcd= [HW,CD]
  668. Format: <port>,<irq>,<mitsumi_bug_93_wait>
  669. mcdx= [HW,CD]
  670. mce [IA-32] Machine Check Exception
  671. md= [HW] RAID subsystems devices and level
  672. See Documentation/md.txt.
  673. mdacon= [MDA]
  674. Format: <first>,<last>
  675. Specifies range of consoles to be captured by the MDA.
  676. mem=nn[KMG] [KNL,BOOT] Force usage of a specific amount of memory
  677. Amount of memory to be used when the kernel is not able
  678. to see the whole system memory or for test.
  679. [IA-32] Use together with memmap= to avoid physical
  680. address space collisions. Without memmap= PCI devices
  681. could be placed at addresses belonging to unused RAM.
  682. mem=nopentium [BUGS=IA-32] Disable usage of 4MB pages for kernel
  683. memory.
  684. memmap=exactmap [KNL,IA-32,X86_64] Enable setting of an exact
  685. E820 memory map, as specified by the user.
  686. Such memmap=exactmap lines can be constructed based on
  687. BIOS output or other requirements. See the memmap=nn@ss
  688. option description.
  689. memmap=nn[KMG]@ss[KMG]
  690. [KNL] Force usage of a specific region of memory
  691. Region of memory to be used, from ss to ss+nn.
  692. memmap=nn[KMG]#ss[KMG]
  693. [KNL,ACPI] Mark specific memory as ACPI data.
  694. Region of memory to be used, from ss to ss+nn.
  695. memmap=nn[KMG]$ss[KMG]
  696. [KNL,ACPI] Mark specific memory as reserved.
  697. Region of memory to be used, from ss to ss+nn.
  698. meye.*= [HW] Set MotionEye Camera parameters
  699. See Documentation/video4linux/meye.txt.
  700. mga= [HW,DRM]
  701. migration_cost=
  702. [KNL,SMP] debug: override scheduler migration costs
  703. Format: <level-1-usecs>,<level-2-usecs>,...
  704. This debugging option can be used to override the
  705. default scheduler migration cost matrix. The numbers
  706. are indexed by 'CPU domain distance'.
  707. E.g. migration_cost=1000,2000,3000 on an SMT NUMA
  708. box will set up an intra-core migration cost of
  709. 1 msec, an inter-core migration cost of 2 msecs,
  710. and an inter-node migration cost of 3 msecs.
  711. WARNING: using the wrong values here can break
  712. scheduler performance, so it's only for scheduler
  713. development purposes, not production environments.
  714. migration_debug=
  715. [KNL,SMP] migration cost auto-detect verbosity
  716. Format=<0|1|2>
  717. If a system's migration matrix reported at bootup
  718. seems erroneous then this option can be used to
  719. increase verbosity of the detection process.
  720. We default to 0 (no extra messages), 1 will print
  721. some more information, and 2 will be really
  722. verbose (probably only useful if you also have a
  723. serial console attached to the system).
  724. migration_factor=
  725. [KNL,SMP] multiply/divide migration costs by a factor
  726. Format=<percent>
  727. This debug option can be used to proportionally
  728. increase or decrease the auto-detected migration
  729. costs for all entries of the migration matrix.
  730. E.g. migration_factor=150 will increase migration
  731. costs by 50%. (and thus the scheduler will be less
  732. eager migrating cache-hot tasks)
  733. migration_factor=80 will decrease migration costs
  734. by 20%. (thus the scheduler will be more eager to
  735. migrate tasks)
  736. WARNING: using the wrong values here can break
  737. scheduler performance, so it's only for scheduler
  738. development purposes, not production environments.
  739. mousedev.tap_time=
  740. [MOUSE] Maximum time between finger touching and
  741. leaving touchpad surface for touch to be considered
  742. a tap and be reported as a left button click (for
  743. touchpads working in absolute mode only).
  744. Format: <msecs>
  745. mousedev.xres= [MOUSE] Horizontal screen resolution, used for devices
  746. reporting absolute coordinates, such as tablets
  747. mousedev.yres= [MOUSE] Vertical screen resolution, used for devices
  748. reporting absolute coordinates, such as tablets
  749. mpu401= [HW,OSS]
  750. Format: <io>,<irq>
  751. MTD_Partition= [MTD]
  752. Format: <name>,<region-number>,<size>,<offset>
  753. MTD_Region= [MTD] Format:
  754. <name>,<region-number>[,<base>,<size>,<buswidth>,<altbuswidth>]
  755. mtdparts= [MTD]
  756. See drivers/mtd/cmdline.c.
  757. mtouchusb.raw_coordinates=
  758. [HW] Make the MicroTouch USB driver use raw coordinates
  759. ('y', default) or cooked coordinates ('n')
  760. n2= [NET] SDL Inc. RISCom/N2 synchronous serial card
  761. NCR_D700= [HW,SCSI]
  762. See header of drivers/scsi/NCR_D700.c.
  763. ncr5380= [HW,SCSI]
  764. ncr53c400= [HW,SCSI]
  765. ncr53c400a= [HW,SCSI]
  766. ncr53c406a= [HW,SCSI]
  767. ncr53c8xx= [HW,SCSI]
  768. netdev= [NET] Network devices parameters
  769. Format: <irq>,<io>,<mem_start>,<mem_end>,<name>
  770. Note that mem_start is often overloaded to mean
  771. something different and driver-specific.
  772. This usage is only documented in each driver source
  773. file if at all.
  774. nfsaddrs= [NFS]
  775. See Documentation/nfsroot.txt.
  776. nfsroot= [NFS] nfs root filesystem for disk-less boxes.
  777. See Documentation/nfsroot.txt.
  778. nfs.callback_tcpport=
  779. [NFS] set the TCP port on which the NFSv4 callback
  780. channel should listen.
  781. nfs.idmap_cache_timeout=
  782. [NFS] set the maximum lifetime for idmapper cache
  783. entries.
  784. nmi_watchdog= [KNL,BUGS=IA-32] Debugging features for SMP kernels
  785. no387 [BUGS=IA-32] Tells the kernel to use the 387 maths
  786. emulation library even if a 387 maths coprocessor
  787. is present.
  788. noaliencache [MM, NUMA] Disables the allcoation of alien caches in
  789. the slab allocator. Saves per-node memory, but will
  790. impact performance on real NUMA hardware.
  791. noalign [KNL,ARM]
  792. noapic [SMP,APIC] Tells the kernel to not make use of any
  793. IOAPICs that may be present in the system.
  794. noasync [HW,M68K] Disables async and sync negotiation for
  795. all devices.
  796. nobats [PPC] Do not use BATs for mapping kernel lowmem
  797. on "Classic" PPC cores.
  798. nocache [ARM]
  799. nodelayacct [KNL] Disable per-task delay accounting
  800. nodisconnect [HW,SCSI,M68K] Disables SCSI disconnects.
  801. noexec [IA-64]
  802. noexec [IA-32,X86-64]
  803. noexec=on: enable non-executable mappings (default)
  804. noexec=off: disable nn-executable mappings
  805. nofxsr [BUGS=IA-32] Disables x86 floating point extended
  806. register save and restore. The kernel will only save
  807. legacy floating-point registers on task switch.
  808. nohlt [BUGS=ARM]
  809. no-hlt [BUGS=IA-32] Tells the kernel that the hlt
  810. instruction doesn't work correctly and not to
  811. use it.
  812. nohalt [IA-64] Tells the kernel not to use the power saving
  813. function PAL_HALT_LIGHT when idle. This increases
  814. power-consumption. On the positive side, it reduces
  815. interrupt wake-up latency, which may improve performance
  816. in certain environments such as networked servers or
  817. real-time systems.
  818. noirqbalance [IA-32,SMP,KNL] Disable kernel irq balancing
  819. noirqdebug [IA-32] Disables the code which attempts to detect and
  820. disable unhandled interrupt sources.
  821. no_timer_check [IA-32,X86_64,APIC] Disables the code which tests for
  822. broken timer IRQ sources.
  823. noisapnp [ISAPNP] Disables ISA PnP code.
  824. noinitrd [RAM] Tells the kernel not to load any configured
  825. initial RAM disk.
  826. nointroute [IA-64]
  827. nolapic [IA-32,APIC] Do not enable or use the local APIC.
  828. noltlbs [PPC] Do not use large page/tlb entries for kernel
  829. lowmem mapping on PPC40x.
  830. nomca [IA-64] Disable machine check abort handling
  831. nomce [IA-32] Machine Check Exception
  832. noresidual [PPC] Don't use residual data on PReP machines.
  833. noresume [SWSUSP] Disables resume and restores original swap
  834. space.
  835. no-scroll [VGA] Disables scrollback.
  836. This is required for the Braillex ib80-piezo Braille
  837. reader made by F.H. Papenmeier (Germany).
  838. nosbagart [IA-64]
  839. nosep [BUGS=IA-32] Disables x86 SYSENTER/SYSEXIT support.
  840. nosmp [SMP] Tells an SMP kernel to act as a UP kernel.
  841. nosync [HW,M68K] Disables sync negotiation for all devices.
  842. notsc [BUGS=IA-32] Disable Time Stamp Counter
  843. nousb [USB] Disable the USB subsystem
  844. nowb [ARM]
  845. nr_uarts= [SERIAL] maximum number of UARTs to be registered.
  846. opl3= [HW,OSS]
  847. Format: <io>
  848. opl3sa2= [HW,OSS] Format:
  849. <io>,<irq>,<dma>,<dma2>,<mss_io>,<mpu_io>,<ymode>,<loopback>[,<isapnp>,<multiple]
  850. oprofile.timer= [HW]
  851. Use timer interrupt instead of performance counters
  852. optcd= [HW,CD]
  853. Format: <io>
  854. osst= [HW,SCSI] SCSI Tape Driver
  855. Format: <buffer_size>,<write_threshold>
  856. See also Documentation/scsi/st.txt.
  857. panic= [KNL] Kernel behaviour on panic
  858. Format: <timeout>
  859. parkbd.port= [HW] Parallel port number the keyboard adapter is
  860. connected to, default is 0.
  861. Format: <parport#>
  862. parkbd.mode= [HW] Parallel port keyboard adapter mode of operation,
  863. 0 for XT, 1 for AT (default is AT).
  864. Format: <mode>
  865. parport= [HW,PPT] Specify parallel ports. 0 disables.
  866. Format: { 0 | auto | 0xBBB[,IRQ[,DMA]] }
  867. Use 'auto' to force the driver to use any
  868. IRQ/DMA settings detected (the default is to
  869. ignore detected IRQ/DMA settings because of
  870. possible conflicts). You can specify the base
  871. address, IRQ, and DMA settings; IRQ and DMA
  872. should be numbers, or 'auto' (for using detected
  873. settings on that particular port), or 'nofifo'
  874. (to avoid using a FIFO even if it is detected).
  875. Parallel ports are assigned in the order they
  876. are specified on the command line, starting
  877. with parport0.
  878. parport_init_mode= [HW,PPT]
  879. Configure VIA parallel port to operate in
  880. a specific mode. This is necessary on Pegasos
  881. computer where firmware has no options for setting
  882. up parallel port mode and sets it to spp.
  883. Currently this function knows 686a and 8231 chips.
  884. Format: [spp|ps2|epp|ecp|ecpepp]
  885. pas2= [HW,OSS] Format:
  886. <io>,<irq>,<dma>,<dma16>,<sb_io>,<sb_irq>,<sb_dma>,<sb_dma16>
  887. pas16= [HW,SCSI]
  888. See header of drivers/scsi/pas16.c.
  889. pause_on_oops=
  890. Halt all CPUs after the first oops has been printed for
  891. the specified number of seconds. This is to be used if
  892. your oopses keep scrolling off the screen.
  893. pcbit= [HW,ISDN]
  894. pcd. [PARIDE]
  895. See header of drivers/block/paride/pcd.c.
  896. See also Documentation/paride.txt.
  897. pci=option[,option...] [PCI] various PCI subsystem options:
  898. off [IA-32] don't probe for the PCI bus
  899. bios [IA-32] force use of PCI BIOS, don't access
  900. the hardware directly. Use this if your machine
  901. has a non-standard PCI host bridge.
  902. nobios [IA-32] disallow use of PCI BIOS, only direct
  903. hardware access methods are allowed. Use this
  904. if you experience crashes upon bootup and you
  905. suspect they are caused by the BIOS.
  906. conf1 [IA-32] Force use of PCI Configuration
  907. Mechanism 1.
  908. conf2 [IA-32] Force use of PCI Configuration
  909. Mechanism 2.
  910. nommconf [IA-32,X86_64] Disable use of MMCONFIG for PCI
  911. Configuration
  912. nomsi [MSI] If the PCI_MSI kernel config parameter is
  913. enabled, this kernel boot option can be used to
  914. disable the use of MSI interrupts system-wide.
  915. nosort [IA-32] Don't sort PCI devices according to
  916. order given by the PCI BIOS. This sorting is
  917. done to get a device order compatible with
  918. older kernels.
  919. biosirq [IA-32] Use PCI BIOS calls to get the interrupt
  920. routing table. These calls are known to be buggy
  921. on several machines and they hang the machine
  922. when used, but on other computers it's the only
  923. way to get the interrupt routing table. Try
  924. this option if the kernel is unable to allocate
  925. IRQs or discover secondary PCI buses on your
  926. motherboard.
  927. rom [IA-32] Assign address space to expansion ROMs.
  928. Use with caution as certain devices share
  929. address decoders between ROMs and other
  930. resources.
  931. irqmask=0xMMMM [IA-32] Set a bit mask of IRQs allowed to be
  932. assigned automatically to PCI devices. You can
  933. make the kernel exclude IRQs of your ISA cards
  934. this way.
  935. pirqaddr=0xAAAAA [IA-32] Specify the physical address
  936. of the PIRQ table (normally generated
  937. by the BIOS) if it is outside the
  938. F0000h-100000h range.
  939. lastbus=N [IA-32] Scan all buses thru bus #N. Can be
  940. useful if the kernel is unable to find your
  941. secondary buses and you want to tell it
  942. explicitly which ones they are.
  943. assign-busses [IA-32] Always assign all PCI bus
  944. numbers ourselves, overriding
  945. whatever the firmware may have done.
  946. usepirqmask [IA-32] Honor the possible IRQ mask stored
  947. in the BIOS $PIR table. This is needed on
  948. some systems with broken BIOSes, notably
  949. some HP Pavilion N5400 and Omnibook XE3
  950. notebooks. This will have no effect if ACPI
  951. IRQ routing is enabled.
  952. noacpi [IA-32] Do not use ACPI for IRQ routing
  953. or for PCI scanning.
  954. routeirq Do IRQ routing for all PCI devices.
  955. This is normally done in pci_enable_device(),
  956. so this option is a temporary workaround
  957. for broken drivers that don't call it.
  958. firmware [ARM] Do not re-enumerate the bus but instead
  959. just use the configuration from the
  960. bootloader. This is currently used on
  961. IXP2000 systems where the bus has to be
  962. configured a certain way for adjunct CPUs.
  963. noearly [X86] Don't do any early type 1 scanning.
  964. This might help on some broken boards which
  965. machine check when some devices' config space
  966. is read. But various workarounds are disabled
  967. and some IOMMU drivers will not work.
  968. bfsort Sort PCI devices into breadth-first order.
  969. This sorting is done to get a device
  970. order compatible with older (<= 2.4) kernels.
  971. nobfsort Don't sort PCI devices into breadth-first order.
  972. pcmv= [HW,PCMCIA] BadgePAD 4
  973. pd. [PARIDE]
  974. See Documentation/paride.txt.
  975. pdcchassis= [PARISC,HW] Disable/Enable PDC Chassis Status codes at
  976. boot time.
  977. Format: { 0 | 1 }
  978. See arch/parisc/kernel/pdc_chassis.c
  979. pf. [PARIDE]
  980. See Documentation/paride.txt.
  981. pg. [PARIDE]
  982. See Documentation/paride.txt.
  983. pirq= [SMP,APIC] Manual mp-table setup
  984. See Documentation/i386/IO-APIC.txt.
  985. plip= [PPT,NET] Parallel port network link
  986. Format: { parport<nr> | timid | 0 }
  987. See also Documentation/parport.txt.
  988. pnpacpi= [ACPI]
  989. { off }
  990. pnpbios= [ISAPNP]
  991. { on | off | curr | res | no-curr | no-res }
  992. pnp_reserve_irq=
  993. [ISAPNP] Exclude IRQs for the autoconfiguration
  994. pnp_reserve_dma=
  995. [ISAPNP] Exclude DMAs for the autoconfiguration
  996. pnp_reserve_io= [ISAPNP] Exclude I/O ports for the autoconfiguration
  997. Ranges are in pairs (I/O port base and size).
  998. pnp_reserve_mem=
  999. [ISAPNP] Exclude memory regions for the
  1000. autoconfiguration.
  1001. Ranges are in pairs (memory base and size).
  1002. profile= [KNL] Enable kernel profiling via /proc/profile
  1003. Format: [schedule,]<number>
  1004. Param: "schedule" - profile schedule points.
  1005. Param: <number> - step/bucket size as a power of 2 for
  1006. statistical time based profiling.
  1007. Param: "sleep" - profile D-state sleeping (millisecs)
  1008. processor.max_cstate= [HW,ACPI]
  1009. Limit processor to maximum C-state
  1010. max_cstate=9 overrides any DMI blacklist limit.
  1011. processor.nocst [HW,ACPI]
  1012. Ignore the _CST method to determine C-states,
  1013. instead using the legacy FADT method
  1014. prompt_ramdisk= [RAM] List of RAM disks to prompt for floppy disk
  1015. before loading.
  1016. See Documentation/ramdisk.txt.
  1017. psmouse.proto= [HW,MOUSE] Highest PS2 mouse protocol extension to
  1018. probe for; one of (bare|imps|exps|lifebook|any).
  1019. psmouse.rate= [HW,MOUSE] Set desired mouse report rate, in reports
  1020. per second.
  1021. psmouse.resetafter= [HW,MOUSE]
  1022. Try to reset the device after so many bad packets
  1023. (0 = never).
  1024. psmouse.resolution=
  1025. [HW,MOUSE] Set desired mouse resolution, in dpi.
  1026. psmouse.smartscroll=
  1027. [HW,MOUSE] Controls Logitech smartscroll autorepeat.
  1028. 0 = disabled, 1 = enabled (default).
  1029. pss= [HW,OSS] Personal Sound System (ECHO ESC614)
  1030. Format:
  1031. <io>,<mss_io>,<mss_irq>,<mss_dma>,<mpu_io>,<mpu_irq>
  1032. pt. [PARIDE]
  1033. See Documentation/paride.txt.
  1034. quiet [KNL] Disable most log messages
  1035. r128= [HW,DRM]
  1036. raid= [HW,RAID]
  1037. See Documentation/md.txt.
  1038. ramdisk= [RAM] Sizes of RAM disks in kilobytes [deprecated]
  1039. See Documentation/ramdisk.txt.
  1040. ramdisk_blocksize= [RAM]
  1041. See Documentation/ramdisk.txt.
  1042. ramdisk_size= [RAM] Sizes of RAM disks in kilobytes
  1043. New name for the ramdisk parameter.
  1044. See Documentation/ramdisk.txt.
  1045. rcu.blimit= [KNL,BOOT] Set maximum number of finished
  1046. RCU callbacks to process in one batch.
  1047. rcu.qhimark= [KNL,BOOT] Set threshold of queued
  1048. RCU callbacks over which batch limiting is disabled.
  1049. rcu.qlowmark= [KNL,BOOT] Set threshold of queued
  1050. RCU callbacks below which batch limiting is re-enabled.
  1051. rdinit= [KNL]
  1052. Format: <full_path>
  1053. Run specified binary instead of /init from the ramdisk,
  1054. used for early userspace startup. See initrd.
  1055. reboot= [BUGS=IA-32,BUGS=ARM,BUGS=IA-64] Rebooting mode
  1056. Format: <reboot_mode>[,<reboot_mode2>[,...]]
  1057. See arch/*/kernel/reboot.c or arch/*/kernel/process.c
  1058. reserve= [KNL,BUGS] Force the kernel to ignore some iomem area
  1059. reservetop= [IA-32]
  1060. Format: nn[KMG]
  1061. Reserves a hole at the top of the kernel virtual
  1062. address space.
  1063. reset_devices [KNL] Force drivers to reset the underlying device
  1064. during initialization.
  1065. resume= [SWSUSP]
  1066. Specify the partition device for software suspend
  1067. resume_offset= [SWSUSP]
  1068. Specify the offset from the beginning of the partition
  1069. given by "resume=" at which the swap header is located,
  1070. in <PAGE_SIZE> units (needed only for swap files).
  1071. See Documentation/power/swsusp-and-swap-files.txt
  1072. rhash_entries= [KNL,NET]
  1073. Set number of hash buckets for route cache
  1074. riscom8= [HW,SERIAL]
  1075. Format: <io_board1>[,<io_board2>[,...<io_boardN>]]
  1076. ro [KNL] Mount root device read-only on boot
  1077. root= [KNL] Root filesystem
  1078. rootdelay= [KNL] Delay (in seconds) to pause before attempting to
  1079. mount the root filesystem
  1080. rootflags= [KNL] Set root filesystem mount option string
  1081. rootfstype= [KNL] Set root filesystem type
  1082. rw [KNL] Mount root device read-write on boot
  1083. S [KNL] Run init in single mode
  1084. sa1100ir [NET]
  1085. See drivers/net/irda/sa1100_ir.c.
  1086. sb= [HW,OSS]
  1087. Format: <io>,<irq>,<dma>,<dma2>
  1088. sbni= [NET] Granch SBNI12 leased line adapter
  1089. sbpcd= [HW,CD] Soundblaster CD adapter
  1090. Format: <io>,<type>
  1091. See a comment before function sbpcd_setup() in
  1092. drivers/cdrom/sbpcd.c.
  1093. sc1200wdt= [HW,WDT] SC1200 WDT (watchdog) driver
  1094. Format: <io>[,<timeout>[,<isapnp>]]
  1095. scsi_debug_*= [SCSI]
  1096. See drivers/scsi/scsi_debug.c.
  1097. scsi_default_dev_flags=
  1098. [SCSI] SCSI default device flags
  1099. Format: <integer>
  1100. scsi_dev_flags= [SCSI] Black/white list entry for vendor and model
  1101. Format: <vendor>:<model>:<flags>
  1102. (flags are integer value)
  1103. scsi_logging= [SCSI]
  1104. scsi_mod.scan= [SCSI] sync (default) scans SCSI busses as they are
  1105. discovered. async scans them in kernel threads,
  1106. allowing boot to proceed. none ignores them, expecting
  1107. user space to do the scan.
  1108. selinux [SELINUX] Disable or enable SELinux at boot time.
  1109. Format: { "0" | "1" }
  1110. See security/selinux/Kconfig help text.
  1111. 0 -- disable.
  1112. 1 -- enable.
  1113. Default value is set via kernel config option.
  1114. If enabled at boot time, /selinux/disable can be used
  1115. later to disable prior to initial policy load.
  1116. selinux_compat_net =
  1117. [SELINUX] Set initial selinux_compat_net flag value.
  1118. Format: { "0" | "1" }
  1119. 0 -- use new secmark-based packet controls
  1120. 1 -- use legacy packet controls
  1121. Default value is 0 (preferred).
  1122. Value can be changed at runtime via
  1123. /selinux/compat_net.
  1124. serialnumber [BUGS=IA-32]
  1125. sg_def_reserved_size= [SCSI]
  1126. shapers= [NET]
  1127. Maximal number of shapers.
  1128. sim710= [SCSI,HW]
  1129. See header of drivers/scsi/sim710.c.
  1130. simeth= [IA-64]
  1131. simscsi=
  1132. sjcd= [HW,CD]
  1133. Format: <io>,<irq>,<dma>
  1134. See header of drivers/cdrom/sjcd.c.
  1135. slram= [HW,MTD]
  1136. smart2= [HW]
  1137. Format: <io1>[,<io2>[,...,<io8>]]
  1138. snd-ad1816a= [HW,ALSA]
  1139. snd-ad1848= [HW,ALSA]
  1140. snd-ali5451= [HW,ALSA]
  1141. snd-als100= [HW,ALSA]
  1142. snd-als4000= [HW,ALSA]
  1143. snd-azt2320= [HW,ALSA]
  1144. snd-cmi8330= [HW,ALSA]
  1145. snd-cmipci= [HW,ALSA]
  1146. snd-cs4231= [HW,ALSA]
  1147. snd-cs4232= [HW,ALSA]
  1148. snd-cs4236= [HW,ALSA]
  1149. snd-cs4281= [HW,ALSA]
  1150. snd-cs46xx= [HW,ALSA]
  1151. snd-dt019x= [HW,ALSA]
  1152. snd-dummy= [HW,ALSA]
  1153. snd-emu10k1= [HW,ALSA]
  1154. snd-ens1370= [HW,ALSA]
  1155. snd-ens1371= [HW,ALSA]
  1156. snd-es968= [HW,ALSA]
  1157. snd-es1688= [HW,ALSA]
  1158. snd-es18xx= [HW,ALSA]
  1159. snd-es1938= [HW,ALSA]
  1160. snd-es1968= [HW,ALSA]
  1161. snd-fm801= [HW,ALSA]
  1162. snd-gusclassic= [HW,ALSA]
  1163. snd-gusextreme= [HW,ALSA]
  1164. snd-gusmax= [HW,ALSA]
  1165. snd-hdsp= [HW,ALSA]
  1166. snd-ice1712= [HW,ALSA]
  1167. snd-intel8x0= [HW,ALSA]
  1168. snd-interwave= [HW,ALSA]
  1169. snd-interwave-stb=
  1170. [HW,ALSA]
  1171. snd-korg1212= [HW,ALSA]
  1172. snd-maestro3= [HW,ALSA]
  1173. snd-mpu401= [HW,ALSA]
  1174. snd-mtpav= [HW,ALSA]
  1175. snd-nm256= [HW,ALSA]
  1176. snd-opl3sa2= [HW,ALSA]
  1177. snd-opti92x-ad1848=
  1178. [HW,ALSA]
  1179. snd-opti92x-cs4231=
  1180. [HW,ALSA]
  1181. snd-opti93x= [HW,ALSA]
  1182. snd-pmac= [HW,ALSA]
  1183. snd-rme32= [HW,ALSA]
  1184. snd-rme96= [HW,ALSA]
  1185. snd-rme9652= [HW,ALSA]
  1186. snd-sb8= [HW,ALSA]
  1187. snd-sb16= [HW,ALSA]
  1188. snd-sbawe= [HW,ALSA]
  1189. snd-serial= [HW,ALSA]
  1190. snd-sgalaxy= [HW,ALSA]
  1191. snd-sonicvibes= [HW,ALSA]
  1192. snd-sun-amd7930=
  1193. [HW,ALSA]
  1194. snd-sun-cs4231= [HW,ALSA]
  1195. snd-trident= [HW,ALSA]
  1196. snd-usb-audio= [HW,ALSA,USB]
  1197. snd-via82xx= [HW,ALSA]
  1198. snd-virmidi= [HW,ALSA]
  1199. snd-wavefront= [HW,ALSA]
  1200. snd-ymfpci= [HW,ALSA]
  1201. sonycd535= [HW,CD]
  1202. Format: <io>[,<irq>]
  1203. sonypi.*= [HW] Sony Programmable I/O Control Device driver
  1204. See Documentation/sonypi.txt
  1205. specialix= [HW,SERIAL] Specialix multi-serial port adapter
  1206. See Documentation/specialix.txt.
  1207. spia_io_base= [HW,MTD]
  1208. spia_fio_base=
  1209. spia_pedr=
  1210. spia_peddr=
  1211. sscape= [HW,OSS]
  1212. Format: <io>,<irq>,<dma>,<mpu_io>,<mpu_irq>
  1213. st= [HW,SCSI] SCSI tape parameters (buffers, etc.)
  1214. See Documentation/scsi/st.txt.
  1215. st0x= [HW,SCSI]
  1216. See header of drivers/scsi/seagate.c.
  1217. sti= [PARISC,HW]
  1218. Format: <num>
  1219. Set the STI (builtin display/keyboard on the HP-PARISC
  1220. machines) console (graphic card) which should be used
  1221. as the initial boot-console.
  1222. See also comment in drivers/video/console/sticore.c.
  1223. sti_font= [HW]
  1224. See comment in drivers/video/console/sticore.c.
  1225. stifb= [HW]
  1226. Format: bpp:<bpp1>[:<bpp2>[:<bpp3>...]]
  1227. swiotlb= [IA-64] Number of I/O TLB slabs
  1228. switches= [HW,M68k]
  1229. sym53c416= [HW,SCSI]
  1230. See header of drivers/scsi/sym53c416.c.
  1231. sysrq_always_enabled
  1232. [KNL]
  1233. Ignore sysrq setting - this boot parameter will
  1234. neutralize any effect of /proc/sys/kernel/sysrq.
  1235. Useful for debugging.
  1236. t128= [HW,SCSI]
  1237. See header of drivers/scsi/t128.c.
  1238. tdfx= [HW,DRM]
  1239. thash_entries= [KNL,NET]
  1240. Set number of hash buckets for TCP connection
  1241. time Show timing data prefixed to each printk message line
  1242. clocksource= [GENERIC_TIME] Override the default clocksource
  1243. Override the default clocksource and use the clocksource
  1244. with the name specified.
  1245. tipar.timeout= [HW,PPT]
  1246. Set communications timeout in tenths of a second
  1247. (default 15).
  1248. tipar.delay= [HW,PPT]
  1249. Set inter-bit delay in microseconds (default 10).
  1250. tmc8xx= [HW,SCSI]
  1251. See header of drivers/scsi/seagate.c.
  1252. tmscsim= [HW,SCSI]
  1253. See comment before function dc390_setup() in
  1254. drivers/scsi/tmscsim.c.
  1255. tp720= [HW,PS2]
  1256. trix= [HW,OSS] MediaTrix AudioTrix Pro
  1257. Format:
  1258. <io>,<irq>,<dma>,<dma2>,<sb_io>,<sb_irq>,<sb_dma>,<mpu_io>,<mpu_irq>
  1259. tsdev.xres= [TS] Horizontal screen resolution.
  1260. tsdev.yres= [TS] Vertical screen resolution.
  1261. turbografx.map[2|3]= [HW,JOY]
  1262. TurboGraFX parallel port interface
  1263. Format:
  1264. <port#>,<js1>,<js2>,<js3>,<js4>,<js5>,<js6>,<js7>
  1265. See also Documentation/input/joystick-parport.txt
  1266. u14-34f= [HW,SCSI] UltraStor 14F/34F SCSI host adapter
  1267. See header of drivers/scsi/u14-34f.c.
  1268. uart401= [HW,OSS]
  1269. Format: <io>,<irq>
  1270. uart6850= [HW,OSS]
  1271. Format: <io>,<irq>
  1272. uhci-hcd.ignore_oc=
  1273. [USB] Ignore overcurrent events (default N).
  1274. Some badly-designed motherboards generate lots of
  1275. bogus events, for ports that aren't wired to
  1276. anything. Set this parameter to avoid log spamming.
  1277. Note that genuine overcurrent events won't be
  1278. reported either.
  1279. usbhid.mousepoll=
  1280. [USBHID] The interval which mice are to be polled at.
  1281. vdso= [IA-32]
  1282. vdso=1: enable VDSO (default)
  1283. vdso=0: disable VDSO mapping
  1284. video= [FB] Frame buffer configuration
  1285. See Documentation/fb/modedb.txt.
  1286. vga= [BOOT,IA-32] Select a particular video mode
  1287. See Documentation/i386/boot.txt and
  1288. Documentation/svga.txt.
  1289. Use vga=ask for menu.
  1290. This is actually a boot loader parameter; the value is
  1291. passed to the kernel using a special protocol.
  1292. vmalloc=nn[KMG] [KNL,BOOT] Forces the vmalloc area to have an exact
  1293. size of <nn>. This can be used to increase the
  1294. minimum size (128MB on x86). It can also be used to
  1295. decrease the size and leave more room for directly
  1296. mapped kernel RAM.
  1297. vmhalt= [KNL,S390] Perform z/VM CP command after system halt.
  1298. Format: <command>
  1299. vmpanic= [KNL,S390] Perform z/VM CP command after kernel panic.
  1300. Format: <command>
  1301. vmpoff= [KNL,S390] Perform z/VM CP command after power off.
  1302. Format: <command>
  1303. waveartist= [HW,OSS]
  1304. Format: <io>,<irq>,<dma>,<dma2>
  1305. wd33c93= [HW,SCSI]
  1306. See header of drivers/scsi/wd33c93.c.
  1307. wd7000= [HW,SCSI]
  1308. See header of drivers/scsi/wd7000.c.
  1309. wdt= [WDT] Watchdog
  1310. See Documentation/watchdog/watchdog.txt.
  1311. xd= [HW,XT] Original XT pre-IDE (RLL encoded) disks.
  1312. xd_geo= See header of drivers/block/xd.c.
  1313. xirc2ps_cs= [NET,PCMCIA]
  1314. Format:
  1315. <irq>,<irq_mask>,<io>,<full_duplex>,<do_sound>,<lockup_hack>[,<irq2>[,<irq3>[,<irq4>]]]
  1316. norandmaps Don't use address space randomization
  1317. Equivalent to echo 0 > /proc/sys/kernel/randomize_va_space
  1318. unwind_debug=N N > 0 will enable dwarf2 unwinder debugging
  1319. This is useful to get more information why
  1320. you got a "dwarf2 unwinder stuck"
  1321. ______________________________________________________________________
  1322. TODO:
  1323. Add documentation for ALSA options.
  1324. Add more DRM drivers.