kernel-parameters.txt 54 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. LIBATA Libata driver is enabled
  44. LP Printer support is enabled.
  45. LOOP Loopback device support is enabled.
  46. M68k M68k architecture is enabled.
  47. These options have more detailed description inside of
  48. Documentation/m68k/kernel-options.txt.
  49. MCA MCA bus support is enabled.
  50. MDA MDA console support is enabled.
  51. MOUSE Appropriate mouse support is enabled.
  52. MSI Message Signaled Interrupts (PCI).
  53. MTD MTD support is enabled.
  54. NET Appropriate network support is enabled.
  55. NUMA NUMA support is enabled.
  56. GENERIC_TIME The generic timeofday code is enabled.
  57. NFS Appropriate NFS support is enabled.
  58. OSS OSS sound support is enabled.
  59. PARIDE The ParIDE subsystem is enabled.
  60. PARISC The PA-RISC architecture is enabled.
  61. PCI PCI bus support is enabled.
  62. PCMCIA The PCMCIA subsystem is enabled.
  63. PNP Plug & Play support is enabled.
  64. PPC PowerPC architecture is enabled.
  65. PPT Parallel port support is enabled.
  66. PS2 Appropriate PS/2 support is enabled.
  67. RAM RAM disk support is enabled.
  68. S390 S390 architecture is enabled.
  69. SCSI Appropriate SCSI support is enabled.
  70. A lot of drivers has their options described inside of
  71. Documentation/scsi/.
  72. SELINUX SELinux support is enabled.
  73. SERIAL Serial support is enabled.
  74. SH SuperH architecture is enabled.
  75. SMP The kernel is an SMP kernel.
  76. SPARC Sparc architecture is enabled.
  77. SWSUSP Software suspend is enabled.
  78. TS Appropriate touchscreen support is enabled.
  79. USB USB support is enabled.
  80. USBHID USB Human Interface Device support is enabled.
  81. V4L Video For Linux support is enabled.
  82. VGA The VGA console has been enabled.
  83. VT Virtual terminal support is enabled.
  84. WDT Watchdog support is enabled.
  85. XT IBM PC/XT MFM hard disk support is enabled.
  86. X86-64 X86-64 architecture is enabled.
  87. More X86-64 boot options can be found in
  88. Documentation/x86_64/boot-options.txt .
  89. In addition, the following text indicates that the option:
  90. BUGS= Relates to possible processor bugs on the said processor.
  91. KNL Is a kernel start-up parameter.
  92. BOOT Is a boot loader parameter.
  93. Parameters denoted with BOOT are actually interpreted by the boot
  94. loader, and have no meaning to the kernel directly.
  95. Do not modify the syntax of boot loader parameters without extreme
  96. need or coordination with <Documentation/i386/boot.txt>.
  97. There are also arch-specific kernel-parameters not documented here.
  98. See for example <Documentation/x86_64/boot-options.txt>.
  99. Note that ALL kernel parameters listed below are CASE SENSITIVE, and that
  100. a trailing = on the name of any parameter states that that parameter will
  101. be entered as an environment variable, whereas its absence indicates that
  102. it will appear as a kernel argument readable via /proc/cmdline by programs
  103. running once the system is up.
  104. The number of kernel parameters is not limited, but the length of the
  105. complete command line (parameters including spaces etc.) is limited to
  106. a fixed number of characters. This limit depends on the architecture
  107. and is between 256 and 4096 characters. It is defined in the file
  108. ./include/asm/setup.h as COMMAND_LINE_SIZE.
  109. 53c7xx= [HW,SCSI] Amiga SCSI controllers
  110. See header of drivers/scsi/53c7xx.c.
  111. See also Documentation/scsi/ncr53c7xx.txt.
  112. acpi= [HW,ACPI] Advanced Configuration and Power Interface
  113. Format: { force | off | ht | strict | noirq }
  114. force -- enable ACPI if default was off
  115. off -- disable ACPI if default was on
  116. noirq -- do not use ACPI for IRQ routing
  117. ht -- run only enough ACPI to enable Hyper Threading
  118. strict -- Be less tolerant of platforms that are not
  119. strictly ACPI specification compliant.
  120. See also Documentation/pm.txt, pci=noacpi
  121. acpi_sleep= [HW,ACPI] Sleep options
  122. Format: { s3_bios, s3_mode }
  123. See Documentation/power/video.txt
  124. acpi_sci= [HW,ACPI] ACPI System Control Interrupt trigger mode
  125. Format: { level | edge | high | low }
  126. acpi_irq_balance [HW,ACPI]
  127. ACPI will balance active IRQs
  128. default in APIC mode
  129. acpi_irq_nobalance [HW,ACPI]
  130. ACPI will not move active IRQs (default)
  131. default in PIC mode
  132. acpi_irq_pci= [HW,ACPI] If irq_balance, clear listed IRQs for
  133. use by PCI
  134. Format: <irq>,<irq>...
  135. acpi_irq_isa= [HW,ACPI] If irq_balance, mark listed IRQs used by ISA
  136. Format: <irq>,<irq>...
  137. acpi_os_name= [HW,ACPI] Tell ACPI BIOS the name of the OS
  138. Format: To spoof as Windows 98: ="Microsoft Windows"
  139. acpi_osi= [HW,ACPI] empty param disables _OSI
  140. acpi_serialize [HW,ACPI] force serialization of AML methods
  141. acpi_skip_timer_override [HW,ACPI]
  142. Recognize and ignore IRQ0/pin2 Interrupt Override.
  143. For broken nForce2 BIOS resulting in XT-PIC timer.
  144. acpi_use_timer_override [HW,ACPI}
  145. Use timer override. For some broken Nvidia NF5 boards
  146. that require a timer override, but don't have
  147. HPET
  148. acpi_dbg_layer= [HW,ACPI]
  149. Format: <int>
  150. Each bit of the <int> indicates an ACPI debug layer,
  151. 1: enable, 0: disable. It is useful for boot time
  152. debugging. After system has booted up, it can be set
  153. via /proc/acpi/debug_layer.
  154. acpi_dbg_level= [HW,ACPI]
  155. Format: <int>
  156. Each bit of the <int> indicates an ACPI debug level,
  157. 1: enable, 0: disable. It is useful for boot time
  158. debugging. After system has booted up, it can be set
  159. via /proc/acpi/debug_level.
  160. acpi_fake_ecdt [HW,ACPI] Workaround failure due to BIOS lacking ECDT
  161. acpi_generic_hotkey [HW,ACPI]
  162. Allow consolidated generic hotkey driver to
  163. override platform specific driver.
  164. See also Documentation/acpi-hotkey.txt.
  165. acpi_pm_good [IA-32,X86-64]
  166. Override the pmtimer bug detection: force the kernel
  167. to assume that this machine's pmtimer latches its value
  168. and always returns good values.
  169. enable_timer_pin_1 [i386,x86-64]
  170. Enable PIN 1 of APIC timer
  171. Can be useful to work around chipset bugs
  172. (in particular on some ATI chipsets).
  173. The kernel tries to set a reasonable default.
  174. disable_timer_pin_1 [i386,x86-64]
  175. Disable PIN 1 of APIC timer
  176. Can be useful to work around chipset bugs.
  177. ad1816= [HW,OSS]
  178. Format: <io>,<irq>,<dma>,<dma2>
  179. See also Documentation/sound/oss/AD1816.
  180. ad1848= [HW,OSS]
  181. Format: <io>,<irq>,<dma>,<dma2>,<type>
  182. adlib= [HW,OSS]
  183. Format: <io>
  184. advansys= [HW,SCSI]
  185. See header of drivers/scsi/advansys.c.
  186. advwdt= [HW,WDT] Advantech WDT
  187. Format: <iostart>,<iostop>
  188. aedsp16= [HW,OSS] Audio Excel DSP 16
  189. Format: <io>,<irq>,<dma>,<mss_io>,<mpu_io>,<mpu_irq>
  190. See also header of sound/oss/aedsp16.c.
  191. aha152x= [HW,SCSI]
  192. See Documentation/scsi/aha152x.txt.
  193. aha1542= [HW,SCSI]
  194. Format: <portbase>[,<buson>,<busoff>[,<dmaspeed>]]
  195. aic7xxx= [HW,SCSI]
  196. See Documentation/scsi/aic7xxx.txt.
  197. aic79xx= [HW,SCSI]
  198. See Documentation/scsi/aic79xx.txt.
  199. amijoy.map= [HW,JOY] Amiga joystick support
  200. Map of devices attached to JOY0DAT and JOY1DAT
  201. Format: <a>,<b>
  202. See also Documentation/kernel/input/joystick.txt
  203. analog.map= [HW,JOY] Analog joystick and gamepad support
  204. Specifies type or capabilities of an analog joystick
  205. connected to one of 16 gameports
  206. Format: <type1>,<type2>,..<type16>
  207. apc= [HW,SPARC]
  208. Power management functions (SPARCstation-4/5 + deriv.)
  209. Format: noidle
  210. Disable APC CPU standby support. SPARCstation-Fox does
  211. not play well with APC CPU idle - disable it if you have
  212. APC and your system crashes randomly.
  213. apic= [APIC,i386] Change the output verbosity whilst booting
  214. Format: { quiet (default) | verbose | debug }
  215. Change the amount of debugging information output
  216. when initialising the APIC and IO-APIC components.
  217. apm= [APM] Advanced Power Management
  218. See header of arch/i386/kernel/apm.c.
  219. applicom= [HW]
  220. Format: <mem>,<irq>
  221. arcrimi= [HW,NET] ARCnet - "RIM I" (entirely mem-mapped) cards
  222. Format: <io>,<irq>,<nodeID>
  223. ataflop= [HW,M68k]
  224. atarimouse= [HW,MOUSE] Atari Mouse
  225. atascsi= [HW,SCSI] Atari SCSI
  226. atkbd.extra= [HW] Enable extra LEDs and keys on IBM RapidAccess,
  227. EzKey and similar keyboards
  228. atkbd.reset= [HW] Reset keyboard during initialization
  229. atkbd.set= [HW] Select keyboard code set
  230. Format: <int> (2 = AT (default), 3 = PS/2)
  231. atkbd.scroll= [HW] Enable scroll wheel on MS Office and similar
  232. keyboards
  233. atkbd.softraw= [HW] Choose between synthetic and real raw mode
  234. Format: <bool> (0 = real, 1 = synthetic (default))
  235. atkbd.softrepeat= [HW]
  236. Use software keyboard repeat
  237. autotest [IA64]
  238. aztcd= [HW,CD] Aztech CD268 CDROM driver
  239. Format: <io>,0x79 (?)
  240. baycom_epp= [HW,AX25]
  241. Format: <io>,<mode>
  242. baycom_par= [HW,AX25] BayCom Parallel Port AX.25 Modem
  243. Format: <io>,<mode>
  244. See header of drivers/net/hamradio/baycom_par.c.
  245. baycom_ser_fdx= [HW,AX25]
  246. BayCom Serial Port AX.25 Modem (Full Duplex Mode)
  247. Format: <io>,<irq>,<mode>[,<baud>]
  248. See header of drivers/net/hamradio/baycom_ser_fdx.c.
  249. baycom_ser_hdx= [HW,AX25]
  250. BayCom Serial Port AX.25 Modem (Half Duplex Mode)
  251. Format: <io>,<irq>,<mode>
  252. See header of drivers/net/hamradio/baycom_ser_hdx.c.
  253. blkmtd_device= [HW,MTD]
  254. blkmtd_erasesz=
  255. blkmtd_ro=
  256. blkmtd_bs=
  257. blkmtd_count=
  258. bttv.card= [HW,V4L] bttv (bt848 + bt878 based grabber cards)
  259. bttv.radio= Most important insmod options are available as
  260. kernel args too.
  261. bttv.pll= See Documentation/video4linux/bttv/Insmod-options
  262. bttv.tuner= and Documentation/video4linux/bttv/CARDLIST
  263. BusLogic= [HW,SCSI]
  264. See drivers/scsi/BusLogic.c, comment before function
  265. BusLogic_ParseDriverOptions().
  266. c101= [NET] Moxa C101 synchronous serial card
  267. cachesize= [BUGS=IA-32] Override level 2 CPU cache size detection.
  268. Sometimes CPU hardware bugs make them report the cache
  269. size incorrectly. The kernel will attempt work arounds
  270. to fix known problems, but for some CPUs it is not
  271. possible to determine what the correct size should be.
  272. This option provides an override for these situations.
  273. cdu31a= [HW,CD]
  274. Format: <io>,<irq>[,PAS]
  275. See header of drivers/cdrom/cdu31a.c.
  276. chandev= [HW,NET] Generic channel device initialisation
  277. checkreqprot [SELINUX] Set initial checkreqprot flag value.
  278. Format: { "0" | "1" }
  279. See security/selinux/Kconfig help text.
  280. 0 -- check protection applied by kernel (includes
  281. any implied execute protection).
  282. 1 -- check protection requested by application.
  283. Default value is set via a kernel config option.
  284. Value can be changed at runtime via
  285. /selinux/checkreqprot.
  286. clock= [BUGS=IA-32, HW] gettimeofday clocksource override.
  287. [Deprecated]
  288. Forces specified clocksource (if available) to be used
  289. when calculating gettimeofday(). If specified
  290. clocksource is not available, it defaults to PIT.
  291. Format: { pit | tsc | cyclone | pmtmr }
  292. code_bytes [IA32] How many bytes of object code to print in an
  293. oops report.
  294. Range: 0 - 8192
  295. Default: 64
  296. disable_8254_timer
  297. enable_8254_timer
  298. [IA32/X86_64] Disable/Enable interrupt 0 timer routing
  299. over the 8254 in addition to over the IO-APIC. The
  300. kernel tries to set a sensible default.
  301. hpet= [IA-32,HPET] option to disable HPET and use PIT.
  302. Format: disable
  303. cm206= [HW,CD]
  304. Format: { auto | [<io>,][<irq>] }
  305. com20020= [HW,NET] ARCnet - COM20020 chipset
  306. Format:
  307. <io>[,<irq>[,<nodeID>[,<backplane>[,<ckp>[,<timeout>]]]]]
  308. com90io= [HW,NET] ARCnet - COM90xx chipset (IO-mapped buffers)
  309. Format: <io>[,<irq>]
  310. com90xx= [HW,NET]
  311. ARCnet - COM90xx chipset (memory-mapped buffers)
  312. Format: <io>[,<irq>[,<memstart>]]
  313. condev= [HW,S390] console device
  314. conmode=
  315. console= [KNL] Output console device and options.
  316. tty<n> Use the virtual console device <n>.
  317. ttyS<n>[,options]
  318. ttyUSB0[,options]
  319. Use the specified serial port. The options are of
  320. the form "bbbbpnf", where "bbbb" is the baud rate,
  321. "p" is parity ("n", "o", or "e"), "n" is number of
  322. bits, and "f" is flow control ("r" for RTS or
  323. omit it). Default is "9600n8".
  324. See Documentation/serial-console.txt for more
  325. information. See
  326. Documentation/networking/netconsole.txt for an
  327. alternative.
  328. uart,io,<addr>[,options]
  329. uart,mmio,<addr>[,options]
  330. Start an early, polled-mode console on the 8250/16550
  331. UART at the specified I/O port or MMIO address,
  332. switching to the matching ttyS device later. The
  333. options are the same as for ttyS, above.
  334. cpcihp_generic= [HW,PCI] Generic port I/O CompactPCI driver
  335. Format:
  336. <first_slot>,<last_slot>,<port>,<enum_bit>[,<debug>]
  337. cpia_pp= [HW,PPT]
  338. Format: { parport<nr> | auto | none }
  339. crashkernel=nn[KMG]@ss[KMG]
  340. [KNL] Reserve a chunk of physical memory to
  341. hold a kernel to switch to with kexec on panic.
  342. cs4232= [HW,OSS]
  343. Format: <io>,<irq>,<dma>,<dma2>,<mpuio>,<mpuirq>
  344. cs89x0_dma= [HW,NET]
  345. Format: <dma>
  346. cs89x0_media= [HW,NET]
  347. Format: { rj45 | aui | bnc }
  348. cyclades= [HW,SERIAL] Cyclades multi-serial port adapter.
  349. dasd= [HW,NET]
  350. See header of drivers/s390/block/dasd_devmap.c.
  351. db9.dev[2|3]= [HW,JOY] Multisystem joystick support via parallel port
  352. (one device per port)
  353. Format: <port#>,<type>
  354. See also Documentation/input/joystick-parport.txt
  355. debug [KNL] Enable kernel debugging (events log level).
  356. debug_locks_verbose=
  357. [KNL] verbose self-tests
  358. Format=<0|1>
  359. Print debugging info while doing the locking API
  360. self-tests.
  361. We default to 0 (no extra messages), setting it to
  362. 1 will print _a lot_ more information - normally
  363. only useful to kernel developers.
  364. decnet= [HW,NET]
  365. Format: <area>[,<node>]
  366. See also Documentation/networking/decnet.txt.
  367. dhash_entries= [KNL]
  368. Set number of hash buckets for dentry cache.
  369. digi= [HW,SERIAL]
  370. IO parameters + enable/disable command.
  371. digiepca= [HW,SERIAL]
  372. See drivers/char/README.epca and
  373. Documentation/digiepca.txt.
  374. dmascc= [HW,AX25,SERIAL] AX.25 Z80SCC driver with DMA
  375. support available.
  376. Format: <io_dev0>[,<io_dev1>[,..<io_dev32>]]
  377. dmasound= [HW,OSS] Sound subsystem buffers
  378. dscc4.setup= [NET]
  379. dtc3181e= [HW,SCSI]
  380. earlyprintk= [IA-32,X86-64,SH]
  381. earlyprintk=vga
  382. earlyprintk=serial[,ttySn[,baudrate]]
  383. Append ",keep" to not disable it when the real console
  384. takes over.
  385. Only vga or serial at a time, not both.
  386. Currently only ttyS0 and ttyS1 are supported.
  387. Interaction with the standard serial driver is not
  388. very good.
  389. The VGA output is eventually overwritten by the real
  390. console.
  391. eata= [HW,SCSI]
  392. ec_intr= [HW,ACPI] ACPI Embedded Controller interrupt mode
  393. Format: <int>
  394. 0: polling mode
  395. non-0: interrupt mode (default)
  396. eda= [HW,PS2]
  397. edb= [HW,PS2]
  398. edd= [EDD]
  399. Format: {"of[f]" | "sk[ipmbr]"}
  400. See comment in arch/i386/boot/edd.S
  401. eicon= [HW,ISDN]
  402. Format: <id>,<membase>,<irq>
  403. eisa_irq_edge= [PARISC,HW]
  404. See header of drivers/parisc/eisa.c.
  405. elanfreq= [IA-32]
  406. See comment before function elanfreq_setup() in
  407. arch/i386/kernel/cpu/cpufreq/elanfreq.c.
  408. elevator= [IOSCHED]
  409. Format: {"anticipatory" | "cfq" | "deadline" | "noop"}
  410. See Documentation/block/as-iosched.txt and
  411. Documentation/block/deadline-iosched.txt for details.
  412. elfcorehdr= [IA-32, X86_64]
  413. Specifies physical address of start of kernel core
  414. image elf header. Generally kexec loader will
  415. pass this option to capture kernel.
  416. See Documentation/kdump/kdump.txt for details.
  417. enforcing [SELINUX] Set initial enforcing status.
  418. Format: {"0" | "1"}
  419. See security/selinux/Kconfig help text.
  420. 0 -- permissive (log only, no denials).
  421. 1 -- enforcing (deny and log).
  422. Default value is 0.
  423. Value can be changed at runtime via /selinux/enforce.
  424. es1371= [HW,OSS]
  425. Format: <spdif>,[<nomix>,[<amplifier>]]
  426. See also header of sound/oss/es1371.c.
  427. ether= [HW,NET] Ethernet cards parameters
  428. This option is obsoleted by the "netdev=" option, which
  429. has equivalent usage. See its documentation for details.
  430. eurwdt= [HW,WDT] Eurotech CPU-1220/1410 onboard watchdog.
  431. Format: <io>[,<irq>]
  432. failslab=
  433. fail_page_alloc=
  434. fail_make_request=[KNL]
  435. General fault injection mechanism.
  436. Format: <interval>,<probability>,<space>,<times>
  437. See also /Documentation/fault-injection/.
  438. fd_mcs= [HW,SCSI]
  439. See header of drivers/scsi/fd_mcs.c.
  440. fdomain= [HW,SCSI]
  441. See header of drivers/scsi/fdomain.c.
  442. floppy= [HW]
  443. See Documentation/floppy.txt.
  444. gamecon.map[2|3]=
  445. [HW,JOY] Multisystem joystick and NES/SNES/PSX pad
  446. support via parallel port (up to 5 devices per port)
  447. Format: <port#>,<pad1>,<pad2>,<pad3>,<pad4>,<pad5>
  448. See also Documentation/input/joystick-parport.txt
  449. gamma= [HW,DRM]
  450. gdth= [HW,SCSI]
  451. See header of drivers/scsi/gdth.c.
  452. gpt [EFI] Forces disk with valid GPT signature but
  453. invalid Protective MBR to be treated as GPT.
  454. gscd= [HW,CD]
  455. Format: <io>
  456. gvp11= [HW,SCSI]
  457. hashdist= [KNL,NUMA] Large hashes allocated during boot
  458. are distributed across NUMA nodes. Defaults on
  459. for IA-64, off otherwise.
  460. Format: 0 | 1 (for off | on)
  461. hcl= [IA-64] SGI's Hardware Graph compatibility layer
  462. hd= [EIDE] (E)IDE hard drive subsystem geometry
  463. Format: <cyl>,<head>,<sect>
  464. hd?= [HW] (E)IDE subsystem
  465. hd?lun= See Documentation/ide.txt.
  466. highmem=nn[KMG] [KNL,BOOT] forces the highmem zone to have an exact
  467. size of <nn>. This works even on boxes that have no
  468. highmem otherwise. This also works to reduce highmem
  469. size on bigger boxes.
  470. highres= [KNL] Enable/disable high resolution timer mode.
  471. Valid parameters: "on", "off"
  472. Default: "on"
  473. hisax= [HW,ISDN]
  474. See Documentation/isdn/README.HiSax.
  475. hugepages= [HW,IA-32,IA-64] Maximal number of HugeTLB pages.
  476. i8042.direct [HW] Put keyboard port into non-translated mode
  477. i8042.dumbkbd [HW] Pretend that controller can only read data from
  478. keyboard and cannot control its state
  479. (Don't attempt to blink the leds)
  480. i8042.noaux [HW] Don't check for auxiliary (== mouse) port
  481. i8042.nokbd [HW] Don't check/create keyboard port
  482. i8042.nomux [HW] Don't check presence of an active multiplexing
  483. controller
  484. i8042.nopnp [HW] Don't use ACPIPnP / PnPBIOS to discover KBD/AUX
  485. controllers
  486. i8042.panicblink=
  487. [HW] Frequency with which keyboard LEDs should blink
  488. when kernel panics (default is 0.5 sec)
  489. i8042.reset [HW] Reset the controller during init and cleanup
  490. i8042.unlock [HW] Unlock (ignore) the keylock
  491. i810= [HW,DRM]
  492. i8k.ignore_dmi [HW] Continue probing hardware even if DMI data
  493. indicates that the driver is running on unsupported
  494. hardware.
  495. i8k.force [HW] Activate i8k driver even if SMM BIOS signature
  496. does not match list of supported models.
  497. i8k.power_status
  498. [HW] Report power status in /proc/i8k
  499. (disabled by default)
  500. i8k.restricted [HW] Allow controlling fans only if SYS_ADMIN
  501. capability is set.
  502. ibmmcascsi= [HW,MCA,SCSI] IBM MicroChannel SCSI adapter
  503. See Documentation/mca.txt.
  504. icn= [HW,ISDN]
  505. Format: <io>[,<membase>[,<icn_id>[,<icn_id2>]]]
  506. ide= [HW] (E)IDE subsystem
  507. Format: ide=nodma or ide=doubler or ide=reverse
  508. See Documentation/ide.txt.
  509. ide?= [HW] (E)IDE subsystem
  510. Format: ide?=noprobe or chipset specific parameters.
  511. See Documentation/ide.txt.
  512. idebus= [HW] (E)IDE subsystem - VLB/PCI bus speed
  513. See Documentation/ide.txt.
  514. idle= [HW]
  515. Format: idle=poll or idle=halt
  516. ignore_loglevel [KNL]
  517. Ignore loglevel setting - this will print /all/
  518. kernel messages to the console. Useful for debugging.
  519. ihash_entries= [KNL]
  520. Set number of hash buckets for inode cache.
  521. in2000= [HW,SCSI]
  522. See header of drivers/scsi/in2000.c.
  523. init= [KNL]
  524. Format: <full_path>
  525. Run specified binary instead of /sbin/init as init
  526. process.
  527. initcall_debug [KNL] Trace initcalls as they are executed. Useful
  528. for working out where the kernel is dying during
  529. startup.
  530. initrd= [BOOT] Specify the location of the initial ramdisk
  531. inport.irq= [HW] Inport (ATI XL and Microsoft) busmouse driver
  532. Format: <irq>
  533. combined_mode= [HW] control which driver uses IDE ports in combined
  534. mode: legacy IDE driver, libata, or both
  535. (in the libata case, libata.atapi_enabled=1 may be
  536. useful as well). Note that using the ide or libata
  537. options may affect your device naming (e.g. by
  538. changing hdc to sdb).
  539. Format: combined (default), ide, or libata
  540. inttest= [IA64]
  541. io7= [HW] IO7 for Marvel based alpha systems
  542. See comment before marvel_specify_io7 in
  543. arch/alpha/kernel/core_marvel.c.
  544. ip= [IP_PNP]
  545. See Documentation/nfsroot.txt.
  546. ip2= [HW] Set IO/IRQ pairs for up to 4 IntelliPort boards
  547. See comment before ip2_setup() in drivers/char/ip2.c.
  548. ips= [HW,SCSI] Adaptec / IBM ServeRAID controller
  549. See header of drivers/scsi/ips.c.
  550. ports= [IP_VS_FTP] IPVS ftp helper module
  551. Default is 21.
  552. Up to 8 (IP_VS_APP_MAX_PORTS) ports
  553. may be specified.
  554. Format: <port>,<port>....
  555. irqfixup [HW]
  556. When an interrupt is not handled search all handlers
  557. for it. Intended to get systems with badly broken
  558. firmware running.
  559. irqpoll [HW]
  560. When an interrupt is not handled search all handlers
  561. for it. Also check all handlers each timer
  562. interrupt. Intended to get systems with badly broken
  563. firmware running.
  564. isapnp= [ISAPNP]
  565. Format: <RDP>,<reset>,<pci_scan>,<verbosity>
  566. isolcpus= [KNL,SMP] Isolate CPUs from the general scheduler.
  567. Format:
  568. <cpu number>,...,<cpu number>
  569. or
  570. <cpu number>-<cpu number> (must be a positive range in ascending order)
  571. or a mixture
  572. <cpu number>,...,<cpu number>-<cpu number>
  573. This option can be used to specify one or more CPUs
  574. to isolate from the general SMP balancing and scheduling
  575. algorithms. The only way to move a process onto or off
  576. an "isolated" CPU is via the CPU affinity syscalls.
  577. <cpu number> begins at 0 and the maximum value is
  578. "number of CPUs in system - 1".
  579. This option is the preferred way to isolate CPUs. The
  580. alternative -- manually setting the CPU mask of all
  581. tasks in the system -- can cause problems and
  582. suboptimal load balancer performance.
  583. isp16= [HW,CD]
  584. Format: <io>,<irq>,<dma>,<setup>
  585. iucv= [HW,NET]
  586. js= [HW,JOY] Analog joystick
  587. See Documentation/input/joystick.txt.
  588. keepinitrd [HW,ARM]
  589. kstack=N [IA-32,X86-64] Print N words from the kernel stack
  590. in oops dumps.
  591. l2cr= [PPC]
  592. lapic [IA-32,APIC] Enable the local APIC even if BIOS
  593. disabled it.
  594. lasi= [HW,SCSI] PARISC LASI driver for the 53c700 chip
  595. Format: addr:<io>,irq:<irq>
  596. llsc*= [IA64] See function print_params() in
  597. arch/ia64/sn/kernel/llsc4.c.
  598. load_ramdisk= [RAM] List of ramdisks to load from floppy
  599. See Documentation/ramdisk.txt.
  600. lockd.nlm_grace_period=P [NFS] Assign grace period.
  601. Format: <integer>
  602. lockd.nlm_tcpport=N [NFS] Assign TCP port.
  603. Format: <integer>
  604. lockd.nlm_timeout=T [NFS] Assign timeout value.
  605. Format: <integer>
  606. lockd.nlm_udpport=M [NFS] Assign UDP port.
  607. Format: <integer>
  608. logibm.irq= [HW,MOUSE] Logitech Bus Mouse Driver
  609. Format: <irq>
  610. loglevel= All Kernel Messages with a loglevel smaller than the
  611. console loglevel will be printed to the console. It can
  612. also be changed with klogd or other programs. The
  613. loglevels are defined as follows:
  614. 0 (KERN_EMERG) system is unusable
  615. 1 (KERN_ALERT) action must be taken immediately
  616. 2 (KERN_CRIT) critical conditions
  617. 3 (KERN_ERR) error conditions
  618. 4 (KERN_WARNING) warning conditions
  619. 5 (KERN_NOTICE) normal but significant condition
  620. 6 (KERN_INFO) informational
  621. 7 (KERN_DEBUG) debug-level messages
  622. log_buf_len=n Sets the size of the printk ring buffer, in bytes.
  623. Format: { n | nk | nM }
  624. n must be a power of two. The default size
  625. is set in the kernel config file.
  626. lp=0 [LP] Specify parallel ports to use, e.g,
  627. lp=port[,port...] lp=none,parport0 (lp0 not configured, lp1 uses
  628. lp=reset first parallel port). 'lp=0' disables the
  629. lp=auto printer driver. 'lp=reset' (which can be
  630. specified in addition to the ports) causes
  631. attached printers to be reset. Using
  632. lp=port1,port2,... specifies the parallel ports
  633. to associate lp devices with, starting with
  634. lp0. A port specification may be 'none' to skip
  635. that lp device, or a parport name such as
  636. 'parport0'. Specifying 'lp=auto' instead of a
  637. port specification list means that device IDs
  638. from each port should be examined, to see if
  639. an IEEE 1284-compliant printer is attached; if
  640. so, the driver will manage that printer.
  641. See also header of drivers/char/lp.c.
  642. lpj=n [KNL]
  643. Sets loops_per_jiffy to given constant, thus avoiding
  644. time-consuming boot-time autodetection (up to 250 ms per
  645. CPU). 0 enables autodetection (default). To determine
  646. the correct value for your kernel, boot with normal
  647. autodetection and see what value is printed. Note that
  648. on SMP systems the preset will be applied to all CPUs,
  649. which is likely to cause problems if your CPUs need
  650. significantly divergent settings. An incorrect value
  651. will cause delays in the kernel to be wrong, leading to
  652. unpredictable I/O errors and other breakage. Although
  653. unlikely, in the extreme case this might damage your
  654. hardware.
  655. ltpc= [NET]
  656. Format: <io>,<irq>,<dma>
  657. mac5380= [HW,SCSI] Format:
  658. <can_queue>,<cmd_per_lun>,<sg_tablesize>,<hostid>,<use_tags>
  659. mac53c9x= [HW,SCSI] Format:
  660. <num_esps>,<disconnect>,<nosync>,<can_queue>,<cmd_per_lun>,<sg_tablesize>,<hostid>,<use_tags>
  661. machvec= [IA64] Force the use of a particular machine-vector
  662. (machvec) in a generic kernel.
  663. Example: machvec=hpzx1_swiotlb
  664. max_loop= [LOOP] Maximum number of loopback devices that can
  665. be mounted
  666. Format: <1-256>
  667. maxcpus= [SMP] Maximum number of processors that an SMP kernel
  668. should make use of.
  669. Using "nosmp" or "maxcpus=0" will disable SMP
  670. entirely (the MPS table probe still happens, though).
  671. A command-line option of "maxcpus=<NUM>", where <NUM>
  672. is an integer greater than 0, limits the maximum number
  673. of CPUs activated in SMP mode to <NUM>.
  674. Using "maxcpus=1" on an SMP kernel is the trivial
  675. case of an SMP kernel with only one CPU.
  676. max_addr=[KMG] [KNL,BOOT,ia64] All physical memory greater than or
  677. equal to this physical address is ignored.
  678. max_luns= [SCSI] Maximum number of LUNs to probe.
  679. Should be between 1 and 2^32-1.
  680. max_report_luns=
  681. [SCSI] Maximum number of LUNs received.
  682. Should be between 1 and 16384.
  683. mca-pentium [BUGS=IA-32]
  684. mcatest= [IA-64]
  685. mcd= [HW,CD]
  686. Format: <port>,<irq>,<mitsumi_bug_93_wait>
  687. mcdx= [HW,CD]
  688. mce [IA-32] Machine Check Exception
  689. md= [HW] RAID subsystems devices and level
  690. See Documentation/md.txt.
  691. mdacon= [MDA]
  692. Format: <first>,<last>
  693. Specifies range of consoles to be captured by the MDA.
  694. mem=nn[KMG] [KNL,BOOT] Force usage of a specific amount of memory
  695. Amount of memory to be used when the kernel is not able
  696. to see the whole system memory or for test.
  697. [IA-32] Use together with memmap= to avoid physical
  698. address space collisions. Without memmap= PCI devices
  699. could be placed at addresses belonging to unused RAM.
  700. mem=nopentium [BUGS=IA-32] Disable usage of 4MB pages for kernel
  701. memory.
  702. memmap=exactmap [KNL,IA-32,X86_64] Enable setting of an exact
  703. E820 memory map, as specified by the user.
  704. Such memmap=exactmap lines can be constructed based on
  705. BIOS output or other requirements. See the memmap=nn@ss
  706. option description.
  707. memmap=nn[KMG]@ss[KMG]
  708. [KNL] Force usage of a specific region of memory
  709. Region of memory to be used, from ss to ss+nn.
  710. memmap=nn[KMG]#ss[KMG]
  711. [KNL,ACPI] Mark specific memory as ACPI data.
  712. Region of memory to be used, from ss to ss+nn.
  713. memmap=nn[KMG]$ss[KMG]
  714. [KNL,ACPI] Mark specific memory as reserved.
  715. Region of memory to be used, from ss to ss+nn.
  716. meye.*= [HW] Set MotionEye Camera parameters
  717. See Documentation/video4linux/meye.txt.
  718. mga= [HW,DRM]
  719. migration_cost=
  720. [KNL,SMP] debug: override scheduler migration costs
  721. Format: <level-1-usecs>,<level-2-usecs>,...
  722. This debugging option can be used to override the
  723. default scheduler migration cost matrix. The numbers
  724. are indexed by 'CPU domain distance'.
  725. E.g. migration_cost=1000,2000,3000 on an SMT NUMA
  726. box will set up an intra-core migration cost of
  727. 1 msec, an inter-core migration cost of 2 msecs,
  728. and an inter-node migration cost of 3 msecs.
  729. WARNING: using the wrong values here can break
  730. scheduler performance, so it's only for scheduler
  731. development purposes, not production environments.
  732. migration_debug=
  733. [KNL,SMP] migration cost auto-detect verbosity
  734. Format=<0|1|2>
  735. If a system's migration matrix reported at bootup
  736. seems erroneous then this option can be used to
  737. increase verbosity of the detection process.
  738. We default to 0 (no extra messages), 1 will print
  739. some more information, and 2 will be really
  740. verbose (probably only useful if you also have a
  741. serial console attached to the system).
  742. migration_factor=
  743. [KNL,SMP] multiply/divide migration costs by a factor
  744. Format=<percent>
  745. This debug option can be used to proportionally
  746. increase or decrease the auto-detected migration
  747. costs for all entries of the migration matrix.
  748. E.g. migration_factor=150 will increase migration
  749. costs by 50%. (and thus the scheduler will be less
  750. eager migrating cache-hot tasks)
  751. migration_factor=80 will decrease migration costs
  752. by 20%. (thus the scheduler will be more eager to
  753. migrate tasks)
  754. WARNING: using the wrong values here can break
  755. scheduler performance, so it's only for scheduler
  756. development purposes, not production environments.
  757. mousedev.tap_time=
  758. [MOUSE] Maximum time between finger touching and
  759. leaving touchpad surface for touch to be considered
  760. a tap and be reported as a left button click (for
  761. touchpads working in absolute mode only).
  762. Format: <msecs>
  763. mousedev.xres= [MOUSE] Horizontal screen resolution, used for devices
  764. reporting absolute coordinates, such as tablets
  765. mousedev.yres= [MOUSE] Vertical screen resolution, used for devices
  766. reporting absolute coordinates, such as tablets
  767. mpu401= [HW,OSS]
  768. Format: <io>,<irq>
  769. MTD_Partition= [MTD]
  770. Format: <name>,<region-number>,<size>,<offset>
  771. MTD_Region= [MTD] Format:
  772. <name>,<region-number>[,<base>,<size>,<buswidth>,<altbuswidth>]
  773. mtdparts= [MTD]
  774. See drivers/mtd/cmdline.c.
  775. mtouchusb.raw_coordinates=
  776. [HW] Make the MicroTouch USB driver use raw coordinates
  777. ('y', default) or cooked coordinates ('n')
  778. n2= [NET] SDL Inc. RISCom/N2 synchronous serial card
  779. NCR_D700= [HW,SCSI]
  780. See header of drivers/scsi/NCR_D700.c.
  781. ncr5380= [HW,SCSI]
  782. ncr53c400= [HW,SCSI]
  783. ncr53c400a= [HW,SCSI]
  784. ncr53c406a= [HW,SCSI]
  785. ncr53c8xx= [HW,SCSI]
  786. netdev= [NET] Network devices parameters
  787. Format: <irq>,<io>,<mem_start>,<mem_end>,<name>
  788. Note that mem_start is often overloaded to mean
  789. something different and driver-specific.
  790. This usage is only documented in each driver source
  791. file if at all.
  792. nfsaddrs= [NFS]
  793. See Documentation/nfsroot.txt.
  794. nfsroot= [NFS] nfs root filesystem for disk-less boxes.
  795. See Documentation/nfsroot.txt.
  796. nfs.callback_tcpport=
  797. [NFS] set the TCP port on which the NFSv4 callback
  798. channel should listen.
  799. nfs.idmap_cache_timeout=
  800. [NFS] set the maximum lifetime for idmapper cache
  801. entries.
  802. nmi_watchdog= [KNL,BUGS=IA-32] Debugging features for SMP kernels
  803. no387 [BUGS=IA-32] Tells the kernel to use the 387 maths
  804. emulation library even if a 387 maths coprocessor
  805. is present.
  806. noacpi [LIBATA] Disables use of ACPI in libata suspend/resume
  807. when set.
  808. Format: <int>
  809. noaliencache [MM, NUMA] Disables the allcoation of alien caches in
  810. the slab allocator. Saves per-node memory, but will
  811. impact performance on real NUMA hardware.
  812. noalign [KNL,ARM]
  813. noapic [SMP,APIC] Tells the kernel to not make use of any
  814. IOAPICs that may be present in the system.
  815. noasync [HW,M68K] Disables async and sync negotiation for
  816. all devices.
  817. nobats [PPC] Do not use BATs for mapping kernel lowmem
  818. on "Classic" PPC cores.
  819. nocache [ARM]
  820. nodelayacct [KNL] Disable per-task delay accounting
  821. nodisconnect [HW,SCSI,M68K] Disables SCSI disconnects.
  822. noexec [IA-64]
  823. noexec [IA-32,X86-64]
  824. noexec=on: enable non-executable mappings (default)
  825. noexec=off: disable nn-executable mappings
  826. nofxsr [BUGS=IA-32] Disables x86 floating point extended
  827. register save and restore. The kernel will only save
  828. legacy floating-point registers on task switch.
  829. nohlt [BUGS=ARM]
  830. no-hlt [BUGS=IA-32] Tells the kernel that the hlt
  831. instruction doesn't work correctly and not to
  832. use it.
  833. nohalt [IA-64] Tells the kernel not to use the power saving
  834. function PAL_HALT_LIGHT when idle. This increases
  835. power-consumption. On the positive side, it reduces
  836. interrupt wake-up latency, which may improve performance
  837. in certain environments such as networked servers or
  838. real-time systems.
  839. nohz= [KNL] Boottime enable/disable dynamic ticks
  840. Valid arguments: on, off
  841. Default: on
  842. noirqbalance [IA-32,SMP,KNL] Disable kernel irq balancing
  843. noirqdebug [IA-32] Disables the code which attempts to detect and
  844. disable unhandled interrupt sources.
  845. no_timer_check [IA-32,X86_64,APIC] Disables the code which tests for
  846. broken timer IRQ sources.
  847. noisapnp [ISAPNP] Disables ISA PnP code.
  848. noinitrd [RAM] Tells the kernel not to load any configured
  849. initial RAM disk.
  850. nointroute [IA-64]
  851. nolapic [IA-32,APIC] Do not enable or use the local APIC.
  852. noltlbs [PPC] Do not use large page/tlb entries for kernel
  853. lowmem mapping on PPC40x.
  854. nomca [IA-64] Disable machine check abort handling
  855. nomce [IA-32] Machine Check Exception
  856. noresidual [PPC] Don't use residual data on PReP machines.
  857. noresume [SWSUSP] Disables resume and restores original swap
  858. space.
  859. no-scroll [VGA] Disables scrollback.
  860. This is required for the Braillex ib80-piezo Braille
  861. reader made by F.H. Papenmeier (Germany).
  862. nosbagart [IA-64]
  863. nosep [BUGS=IA-32] Disables x86 SYSENTER/SYSEXIT support.
  864. nosmp [SMP] Tells an SMP kernel to act as a UP kernel.
  865. nosync [HW,M68K] Disables sync negotiation for all devices.
  866. notsc [BUGS=IA-32] Disable Time Stamp Counter
  867. nousb [USB] Disable the USB subsystem
  868. nowb [ARM]
  869. nr_uarts= [SERIAL] maximum number of UARTs to be registered.
  870. opl3= [HW,OSS]
  871. Format: <io>
  872. opl3sa2= [HW,OSS] Format:
  873. <io>,<irq>,<dma>,<dma2>,<mss_io>,<mpu_io>,<ymode>,<loopback>[,<isapnp>,<multiple]
  874. oprofile.timer= [HW]
  875. Use timer interrupt instead of performance counters
  876. optcd= [HW,CD]
  877. Format: <io>
  878. osst= [HW,SCSI] SCSI Tape Driver
  879. Format: <buffer_size>,<write_threshold>
  880. See also Documentation/scsi/st.txt.
  881. panic= [KNL] Kernel behaviour on panic
  882. Format: <timeout>
  883. parkbd.port= [HW] Parallel port number the keyboard adapter is
  884. connected to, default is 0.
  885. Format: <parport#>
  886. parkbd.mode= [HW] Parallel port keyboard adapter mode of operation,
  887. 0 for XT, 1 for AT (default is AT).
  888. Format: <mode>
  889. parport= [HW,PPT] Specify parallel ports. 0 disables.
  890. Format: { 0 | auto | 0xBBB[,IRQ[,DMA]] }
  891. Use 'auto' to force the driver to use any
  892. IRQ/DMA settings detected (the default is to
  893. ignore detected IRQ/DMA settings because of
  894. possible conflicts). You can specify the base
  895. address, IRQ, and DMA settings; IRQ and DMA
  896. should be numbers, or 'auto' (for using detected
  897. settings on that particular port), or 'nofifo'
  898. (to avoid using a FIFO even if it is detected).
  899. Parallel ports are assigned in the order they
  900. are specified on the command line, starting
  901. with parport0.
  902. parport_init_mode= [HW,PPT]
  903. Configure VIA parallel port to operate in
  904. a specific mode. This is necessary on Pegasos
  905. computer where firmware has no options for setting
  906. up parallel port mode and sets it to spp.
  907. Currently this function knows 686a and 8231 chips.
  908. Format: [spp|ps2|epp|ecp|ecpepp]
  909. pas2= [HW,OSS] Format:
  910. <io>,<irq>,<dma>,<dma16>,<sb_io>,<sb_irq>,<sb_dma>,<sb_dma16>
  911. pas16= [HW,SCSI]
  912. See header of drivers/scsi/pas16.c.
  913. pause_on_oops=
  914. Halt all CPUs after the first oops has been printed for
  915. the specified number of seconds. This is to be used if
  916. your oopses keep scrolling off the screen.
  917. pcbit= [HW,ISDN]
  918. pcd. [PARIDE]
  919. See header of drivers/block/paride/pcd.c.
  920. See also Documentation/paride.txt.
  921. pci=option[,option...] [PCI] various PCI subsystem options:
  922. off [IA-32] don't probe for the PCI bus
  923. bios [IA-32] force use of PCI BIOS, don't access
  924. the hardware directly. Use this if your machine
  925. has a non-standard PCI host bridge.
  926. nobios [IA-32] disallow use of PCI BIOS, only direct
  927. hardware access methods are allowed. Use this
  928. if you experience crashes upon bootup and you
  929. suspect they are caused by the BIOS.
  930. conf1 [IA-32] Force use of PCI Configuration
  931. Mechanism 1.
  932. conf2 [IA-32] Force use of PCI Configuration
  933. Mechanism 2.
  934. nommconf [IA-32,X86_64] Disable use of MMCONFIG for PCI
  935. Configuration
  936. nomsi [MSI] If the PCI_MSI kernel config parameter is
  937. enabled, this kernel boot option can be used to
  938. disable the use of MSI interrupts system-wide.
  939. nosort [IA-32] Don't sort PCI devices according to
  940. order given by the PCI BIOS. This sorting is
  941. done to get a device order compatible with
  942. older kernels.
  943. biosirq [IA-32] Use PCI BIOS calls to get the interrupt
  944. routing table. These calls are known to be buggy
  945. on several machines and they hang the machine
  946. when used, but on other computers it's the only
  947. way to get the interrupt routing table. Try
  948. this option if the kernel is unable to allocate
  949. IRQs or discover secondary PCI buses on your
  950. motherboard.
  951. rom [IA-32] Assign address space to expansion ROMs.
  952. Use with caution as certain devices share
  953. address decoders between ROMs and other
  954. resources.
  955. irqmask=0xMMMM [IA-32] Set a bit mask of IRQs allowed to be
  956. assigned automatically to PCI devices. You can
  957. make the kernel exclude IRQs of your ISA cards
  958. this way.
  959. pirqaddr=0xAAAAA [IA-32] Specify the physical address
  960. of the PIRQ table (normally generated
  961. by the BIOS) if it is outside the
  962. F0000h-100000h range.
  963. lastbus=N [IA-32] Scan all buses thru bus #N. Can be
  964. useful if the kernel is unable to find your
  965. secondary buses and you want to tell it
  966. explicitly which ones they are.
  967. assign-busses [IA-32] Always assign all PCI bus
  968. numbers ourselves, overriding
  969. whatever the firmware may have done.
  970. usepirqmask [IA-32] Honor the possible IRQ mask stored
  971. in the BIOS $PIR table. This is needed on
  972. some systems with broken BIOSes, notably
  973. some HP Pavilion N5400 and Omnibook XE3
  974. notebooks. This will have no effect if ACPI
  975. IRQ routing is enabled.
  976. noacpi [IA-32] Do not use ACPI for IRQ routing
  977. or for PCI scanning.
  978. routeirq Do IRQ routing for all PCI devices.
  979. This is normally done in pci_enable_device(),
  980. so this option is a temporary workaround
  981. for broken drivers that don't call it.
  982. firmware [ARM] Do not re-enumerate the bus but instead
  983. just use the configuration from the
  984. bootloader. This is currently used on
  985. IXP2000 systems where the bus has to be
  986. configured a certain way for adjunct CPUs.
  987. noearly [X86] Don't do any early type 1 scanning.
  988. This might help on some broken boards which
  989. machine check when some devices' config space
  990. is read. But various workarounds are disabled
  991. and some IOMMU drivers will not work.
  992. bfsort Sort PCI devices into breadth-first order.
  993. This sorting is done to get a device
  994. order compatible with older (<= 2.4) kernels.
  995. nobfsort Don't sort PCI devices into breadth-first order.
  996. cbiosize=nn[KMG] The fixed amount of bus space which is
  997. reserved for the CardBus bridge's IO window.
  998. The default value is 256 bytes.
  999. cbmemsize=nn[KMG] The fixed amount of bus space which is
  1000. reserved for the CardBus bridge's memory
  1001. window. The default value is 64 megabytes.
  1002. pcmv= [HW,PCMCIA] BadgePAD 4
  1003. pd. [PARIDE]
  1004. See Documentation/paride.txt.
  1005. pdcchassis= [PARISC,HW] Disable/Enable PDC Chassis Status codes at
  1006. boot time.
  1007. Format: { 0 | 1 }
  1008. See arch/parisc/kernel/pdc_chassis.c
  1009. pf. [PARIDE]
  1010. See Documentation/paride.txt.
  1011. pg. [PARIDE]
  1012. See Documentation/paride.txt.
  1013. pirq= [SMP,APIC] Manual mp-table setup
  1014. See Documentation/i386/IO-APIC.txt.
  1015. plip= [PPT,NET] Parallel port network link
  1016. Format: { parport<nr> | timid | 0 }
  1017. See also Documentation/parport.txt.
  1018. pnpacpi= [ACPI]
  1019. { off }
  1020. pnpbios= [ISAPNP]
  1021. { on | off | curr | res | no-curr | no-res }
  1022. pnp_reserve_irq=
  1023. [ISAPNP] Exclude IRQs for the autoconfiguration
  1024. pnp_reserve_dma=
  1025. [ISAPNP] Exclude DMAs for the autoconfiguration
  1026. pnp_reserve_io= [ISAPNP] Exclude I/O ports for the autoconfiguration
  1027. Ranges are in pairs (I/O port base and size).
  1028. pnp_reserve_mem=
  1029. [ISAPNP] Exclude memory regions for the
  1030. autoconfiguration.
  1031. Ranges are in pairs (memory base and size).
  1032. profile= [KNL] Enable kernel profiling via /proc/profile
  1033. Format: [schedule,]<number>
  1034. Param: "schedule" - profile schedule points.
  1035. Param: <number> - step/bucket size as a power of 2 for
  1036. statistical time based profiling.
  1037. Param: "sleep" - profile D-state sleeping (millisecs)
  1038. processor.max_cstate= [HW,ACPI]
  1039. Limit processor to maximum C-state
  1040. max_cstate=9 overrides any DMI blacklist limit.
  1041. processor.nocst [HW,ACPI]
  1042. Ignore the _CST method to determine C-states,
  1043. instead using the legacy FADT method
  1044. prompt_ramdisk= [RAM] List of RAM disks to prompt for floppy disk
  1045. before loading.
  1046. See Documentation/ramdisk.txt.
  1047. psmouse.proto= [HW,MOUSE] Highest PS2 mouse protocol extension to
  1048. probe for; one of (bare|imps|exps|lifebook|any).
  1049. psmouse.rate= [HW,MOUSE] Set desired mouse report rate, in reports
  1050. per second.
  1051. psmouse.resetafter= [HW,MOUSE]
  1052. Try to reset the device after so many bad packets
  1053. (0 = never).
  1054. psmouse.resolution=
  1055. [HW,MOUSE] Set desired mouse resolution, in dpi.
  1056. psmouse.smartscroll=
  1057. [HW,MOUSE] Controls Logitech smartscroll autorepeat.
  1058. 0 = disabled, 1 = enabled (default).
  1059. pss= [HW,OSS] Personal Sound System (ECHO ESC614)
  1060. Format:
  1061. <io>,<mss_io>,<mss_irq>,<mss_dma>,<mpu_io>,<mpu_irq>
  1062. pt. [PARIDE]
  1063. See Documentation/paride.txt.
  1064. quiet [KNL] Disable most log messages
  1065. r128= [HW,DRM]
  1066. raid= [HW,RAID]
  1067. See Documentation/md.txt.
  1068. ramdisk= [RAM] Sizes of RAM disks in kilobytes [deprecated]
  1069. See Documentation/ramdisk.txt.
  1070. ramdisk_blocksize= [RAM]
  1071. See Documentation/ramdisk.txt.
  1072. ramdisk_size= [RAM] Sizes of RAM disks in kilobytes
  1073. New name for the ramdisk parameter.
  1074. See Documentation/ramdisk.txt.
  1075. rcu.blimit= [KNL,BOOT] Set maximum number of finished
  1076. RCU callbacks to process in one batch.
  1077. rcu.qhimark= [KNL,BOOT] Set threshold of queued
  1078. RCU callbacks over which batch limiting is disabled.
  1079. rcu.qlowmark= [KNL,BOOT] Set threshold of queued
  1080. RCU callbacks below which batch limiting is re-enabled.
  1081. rdinit= [KNL]
  1082. Format: <full_path>
  1083. Run specified binary instead of /init from the ramdisk,
  1084. used for early userspace startup. See initrd.
  1085. reboot= [BUGS=IA-32,BUGS=ARM,BUGS=IA-64] Rebooting mode
  1086. Format: <reboot_mode>[,<reboot_mode2>[,...]]
  1087. See arch/*/kernel/reboot.c or arch/*/kernel/process.c
  1088. reserve= [KNL,BUGS] Force the kernel to ignore some iomem area
  1089. reservetop= [IA-32]
  1090. Format: nn[KMG]
  1091. Reserves a hole at the top of the kernel virtual
  1092. address space.
  1093. reset_devices [KNL] Force drivers to reset the underlying device
  1094. during initialization.
  1095. resume= [SWSUSP]
  1096. Specify the partition device for software suspend
  1097. resume_offset= [SWSUSP]
  1098. Specify the offset from the beginning of the partition
  1099. given by "resume=" at which the swap header is located,
  1100. in <PAGE_SIZE> units (needed only for swap files).
  1101. See Documentation/power/swsusp-and-swap-files.txt
  1102. retain_initrd [RAM] Keep initrd memory after extraction
  1103. rhash_entries= [KNL,NET]
  1104. Set number of hash buckets for route cache
  1105. riscom8= [HW,SERIAL]
  1106. Format: <io_board1>[,<io_board2>[,...<io_boardN>]]
  1107. ro [KNL] Mount root device read-only on boot
  1108. root= [KNL] Root filesystem
  1109. rootdelay= [KNL] Delay (in seconds) to pause before attempting to
  1110. mount the root filesystem
  1111. rootflags= [KNL] Set root filesystem mount option string
  1112. rootfstype= [KNL] Set root filesystem type
  1113. rw [KNL] Mount root device read-write on boot
  1114. S [KNL] Run init in single mode
  1115. sa1100ir [NET]
  1116. See drivers/net/irda/sa1100_ir.c.
  1117. sb= [HW,OSS]
  1118. Format: <io>,<irq>,<dma>,<dma2>
  1119. sbni= [NET] Granch SBNI12 leased line adapter
  1120. sbpcd= [HW,CD] Soundblaster CD adapter
  1121. Format: <io>,<type>
  1122. See a comment before function sbpcd_setup() in
  1123. drivers/cdrom/sbpcd.c.
  1124. sc1200wdt= [HW,WDT] SC1200 WDT (watchdog) driver
  1125. Format: <io>[,<timeout>[,<isapnp>]]
  1126. scsi_debug_*= [SCSI]
  1127. See drivers/scsi/scsi_debug.c.
  1128. scsi_default_dev_flags=
  1129. [SCSI] SCSI default device flags
  1130. Format: <integer>
  1131. scsi_dev_flags= [SCSI] Black/white list entry for vendor and model
  1132. Format: <vendor>:<model>:<flags>
  1133. (flags are integer value)
  1134. scsi_logging= [SCSI]
  1135. scsi_mod.scan= [SCSI] sync (default) scans SCSI busses as they are
  1136. discovered. async scans them in kernel threads,
  1137. allowing boot to proceed. none ignores them, expecting
  1138. user space to do the scan.
  1139. selinux [SELINUX] Disable or enable SELinux at boot time.
  1140. Format: { "0" | "1" }
  1141. See security/selinux/Kconfig help text.
  1142. 0 -- disable.
  1143. 1 -- enable.
  1144. Default value is set via kernel config option.
  1145. If enabled at boot time, /selinux/disable can be used
  1146. later to disable prior to initial policy load.
  1147. selinux_compat_net =
  1148. [SELINUX] Set initial selinux_compat_net flag value.
  1149. Format: { "0" | "1" }
  1150. 0 -- use new secmark-based packet controls
  1151. 1 -- use legacy packet controls
  1152. Default value is 0 (preferred).
  1153. Value can be changed at runtime via
  1154. /selinux/compat_net.
  1155. serialnumber [BUGS=IA-32]
  1156. sg_def_reserved_size= [SCSI]
  1157. shapers= [NET]
  1158. Maximal number of shapers.
  1159. sim710= [SCSI,HW]
  1160. See header of drivers/scsi/sim710.c.
  1161. simeth= [IA-64]
  1162. simscsi=
  1163. sjcd= [HW,CD]
  1164. Format: <io>,<irq>,<dma>
  1165. See header of drivers/cdrom/sjcd.c.
  1166. slram= [HW,MTD]
  1167. smart2= [HW]
  1168. Format: <io1>[,<io2>[,...,<io8>]]
  1169. snd-ad1816a= [HW,ALSA]
  1170. snd-ad1848= [HW,ALSA]
  1171. snd-ali5451= [HW,ALSA]
  1172. snd-als100= [HW,ALSA]
  1173. snd-als4000= [HW,ALSA]
  1174. snd-azt2320= [HW,ALSA]
  1175. snd-cmi8330= [HW,ALSA]
  1176. snd-cmipci= [HW,ALSA]
  1177. snd-cs4231= [HW,ALSA]
  1178. snd-cs4232= [HW,ALSA]
  1179. snd-cs4236= [HW,ALSA]
  1180. snd-cs4281= [HW,ALSA]
  1181. snd-cs46xx= [HW,ALSA]
  1182. snd-dt019x= [HW,ALSA]
  1183. snd-dummy= [HW,ALSA]
  1184. snd-emu10k1= [HW,ALSA]
  1185. snd-ens1370= [HW,ALSA]
  1186. snd-ens1371= [HW,ALSA]
  1187. snd-es968= [HW,ALSA]
  1188. snd-es1688= [HW,ALSA]
  1189. snd-es18xx= [HW,ALSA]
  1190. snd-es1938= [HW,ALSA]
  1191. snd-es1968= [HW,ALSA]
  1192. snd-fm801= [HW,ALSA]
  1193. snd-gusclassic= [HW,ALSA]
  1194. snd-gusextreme= [HW,ALSA]
  1195. snd-gusmax= [HW,ALSA]
  1196. snd-hdsp= [HW,ALSA]
  1197. snd-ice1712= [HW,ALSA]
  1198. snd-intel8x0= [HW,ALSA]
  1199. snd-interwave= [HW,ALSA]
  1200. snd-interwave-stb=
  1201. [HW,ALSA]
  1202. snd-korg1212= [HW,ALSA]
  1203. snd-maestro3= [HW,ALSA]
  1204. snd-mpu401= [HW,ALSA]
  1205. snd-mtpav= [HW,ALSA]
  1206. snd-nm256= [HW,ALSA]
  1207. snd-opl3sa2= [HW,ALSA]
  1208. snd-opti92x-ad1848=
  1209. [HW,ALSA]
  1210. snd-opti92x-cs4231=
  1211. [HW,ALSA]
  1212. snd-opti93x= [HW,ALSA]
  1213. snd-pmac= [HW,ALSA]
  1214. snd-rme32= [HW,ALSA]
  1215. snd-rme96= [HW,ALSA]
  1216. snd-rme9652= [HW,ALSA]
  1217. snd-sb8= [HW,ALSA]
  1218. snd-sb16= [HW,ALSA]
  1219. snd-sbawe= [HW,ALSA]
  1220. snd-serial= [HW,ALSA]
  1221. snd-sgalaxy= [HW,ALSA]
  1222. snd-sonicvibes= [HW,ALSA]
  1223. snd-sun-amd7930=
  1224. [HW,ALSA]
  1225. snd-sun-cs4231= [HW,ALSA]
  1226. snd-trident= [HW,ALSA]
  1227. snd-usb-audio= [HW,ALSA,USB]
  1228. snd-via82xx= [HW,ALSA]
  1229. snd-virmidi= [HW,ALSA]
  1230. snd-wavefront= [HW,ALSA]
  1231. snd-ymfpci= [HW,ALSA]
  1232. sonycd535= [HW,CD]
  1233. Format: <io>[,<irq>]
  1234. sonypi.*= [HW] Sony Programmable I/O Control Device driver
  1235. See Documentation/sonypi.txt
  1236. specialix= [HW,SERIAL] Specialix multi-serial port adapter
  1237. See Documentation/specialix.txt.
  1238. spia_io_base= [HW,MTD]
  1239. spia_fio_base=
  1240. spia_pedr=
  1241. spia_peddr=
  1242. sscape= [HW,OSS]
  1243. Format: <io>,<irq>,<dma>,<mpu_io>,<mpu_irq>
  1244. st= [HW,SCSI] SCSI tape parameters (buffers, etc.)
  1245. See Documentation/scsi/st.txt.
  1246. st0x= [HW,SCSI]
  1247. See header of drivers/scsi/seagate.c.
  1248. sti= [PARISC,HW]
  1249. Format: <num>
  1250. Set the STI (builtin display/keyboard on the HP-PARISC
  1251. machines) console (graphic card) which should be used
  1252. as the initial boot-console.
  1253. See also comment in drivers/video/console/sticore.c.
  1254. sti_font= [HW]
  1255. See comment in drivers/video/console/sticore.c.
  1256. stifb= [HW]
  1257. Format: bpp:<bpp1>[:<bpp2>[:<bpp3>...]]
  1258. sunrpc.pool_mode=
  1259. [NFS]
  1260. Control how the NFS server code allocates CPUs to
  1261. service thread pools. Depending on how many NICs
  1262. you have and where their interrupts are bound, this
  1263. option will affect which CPUs will do NFS serving.
  1264. Note: this parameter cannot be changed while the
  1265. NFS server is running.
  1266. auto the server chooses an appropriate mode
  1267. automatically using heuristics
  1268. global a single global pool contains all CPUs
  1269. percpu one pool for each CPU
  1270. pernode one pool for each NUMA node (equivalent
  1271. to global on non-NUMA machines)
  1272. swiotlb= [IA-64] Number of I/O TLB slabs
  1273. switches= [HW,M68k]
  1274. sym53c416= [HW,SCSI]
  1275. See header of drivers/scsi/sym53c416.c.
  1276. sysrq_always_enabled
  1277. [KNL]
  1278. Ignore sysrq setting - this boot parameter will
  1279. neutralize any effect of /proc/sys/kernel/sysrq.
  1280. Useful for debugging.
  1281. t128= [HW,SCSI]
  1282. See header of drivers/scsi/t128.c.
  1283. tdfx= [HW,DRM]
  1284. thash_entries= [KNL,NET]
  1285. Set number of hash buckets for TCP connection
  1286. time Show timing data prefixed to each printk message line
  1287. clocksource= [GENERIC_TIME] Override the default clocksource
  1288. Override the default clocksource and use the clocksource
  1289. with the name specified.
  1290. tipar.timeout= [HW,PPT]
  1291. Set communications timeout in tenths of a second
  1292. (default 15).
  1293. tipar.delay= [HW,PPT]
  1294. Set inter-bit delay in microseconds (default 10).
  1295. tmc8xx= [HW,SCSI]
  1296. See header of drivers/scsi/seagate.c.
  1297. tmscsim= [HW,SCSI]
  1298. See comment before function dc390_setup() in
  1299. drivers/scsi/tmscsim.c.
  1300. tp720= [HW,PS2]
  1301. trix= [HW,OSS] MediaTrix AudioTrix Pro
  1302. Format:
  1303. <io>,<irq>,<dma>,<dma2>,<sb_io>,<sb_irq>,<sb_dma>,<mpu_io>,<mpu_irq>
  1304. tsdev.xres= [TS] Horizontal screen resolution.
  1305. tsdev.yres= [TS] Vertical screen resolution.
  1306. turbografx.map[2|3]= [HW,JOY]
  1307. TurboGraFX parallel port interface
  1308. Format:
  1309. <port#>,<js1>,<js2>,<js3>,<js4>,<js5>,<js6>,<js7>
  1310. See also Documentation/input/joystick-parport.txt
  1311. u14-34f= [HW,SCSI] UltraStor 14F/34F SCSI host adapter
  1312. See header of drivers/scsi/u14-34f.c.
  1313. uart401= [HW,OSS]
  1314. Format: <io>,<irq>
  1315. uart6850= [HW,OSS]
  1316. Format: <io>,<irq>
  1317. uhci-hcd.ignore_oc=
  1318. [USB] Ignore overcurrent events (default N).
  1319. Some badly-designed motherboards generate lots of
  1320. bogus events, for ports that aren't wired to
  1321. anything. Set this parameter to avoid log spamming.
  1322. Note that genuine overcurrent events won't be
  1323. reported either.
  1324. usbcore.autosuspend=
  1325. [USB] The autosuspend time delay (in seconds) used
  1326. for newly-detected USB devices (default 2). This
  1327. is the time required before an idle device will be
  1328. autosuspended. Devices for which the delay is set
  1329. to 0 won't be autosuspended at all.
  1330. usbhid.mousepoll=
  1331. [USBHID] The interval which mice are to be polled at.
  1332. vdso= [IA-32,SH]
  1333. vdso=1: enable VDSO (default)
  1334. vdso=0: disable VDSO mapping
  1335. video= [FB] Frame buffer configuration
  1336. See Documentation/fb/modedb.txt.
  1337. vga= [BOOT,IA-32] Select a particular video mode
  1338. See Documentation/i386/boot.txt and
  1339. Documentation/svga.txt.
  1340. Use vga=ask for menu.
  1341. This is actually a boot loader parameter; the value is
  1342. passed to the kernel using a special protocol.
  1343. vmalloc=nn[KMG] [KNL,BOOT] Forces the vmalloc area to have an exact
  1344. size of <nn>. This can be used to increase the
  1345. minimum size (128MB on x86). It can also be used to
  1346. decrease the size and leave more room for directly
  1347. mapped kernel RAM.
  1348. vmhalt= [KNL,S390] Perform z/VM CP command after system halt.
  1349. Format: <command>
  1350. vmpanic= [KNL,S390] Perform z/VM CP command after kernel panic.
  1351. Format: <command>
  1352. vmpoff= [KNL,S390] Perform z/VM CP command after power off.
  1353. Format: <command>
  1354. waveartist= [HW,OSS]
  1355. Format: <io>,<irq>,<dma>,<dma2>
  1356. wd33c93= [HW,SCSI]
  1357. See header of drivers/scsi/wd33c93.c.
  1358. wd7000= [HW,SCSI]
  1359. See header of drivers/scsi/wd7000.c.
  1360. wdt= [WDT] Watchdog
  1361. See Documentation/watchdog/watchdog.txt.
  1362. xd= [HW,XT] Original XT pre-IDE (RLL encoded) disks.
  1363. xd_geo= See header of drivers/block/xd.c.
  1364. xirc2ps_cs= [NET,PCMCIA]
  1365. Format:
  1366. <irq>,<irq_mask>,<io>,<full_duplex>,<do_sound>,<lockup_hack>[,<irq2>[,<irq3>[,<irq4>]]]
  1367. norandmaps Don't use address space randomization
  1368. Equivalent to echo 0 > /proc/sys/kernel/randomize_va_space
  1369. unwind_debug=N N > 0 will enable dwarf2 unwinder debugging
  1370. This is useful to get more information why
  1371. you got a "dwarf2 unwinder stuck"
  1372. ______________________________________________________________________
  1373. TODO:
  1374. Add documentation for ALSA options.
  1375. Add more DRM drivers.