kernel-parameters.txt 53 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,X86-64,i386]
  113. Advanced Configuration and Power Interface
  114. Format: { force | off | ht | strict | noirq }
  115. force -- enable ACPI if default was off
  116. off -- disable ACPI if default was on
  117. noirq -- do not use ACPI for IRQ routing
  118. ht -- run only enough ACPI to enable Hyper Threading
  119. strict -- Be less tolerant of platforms that are not
  120. strictly ACPI specification compliant.
  121. See also Documentation/pm.txt, pci=noacpi
  122. acpi_apic_instance= [ACPI, IOAPIC]
  123. Format: <int>
  124. 2: use 2nd APIC table, if available
  125. 1,0: use 1st APIC table
  126. default: 0
  127. acpi_sleep= [HW,ACPI] Sleep options
  128. Format: { s3_bios, s3_mode }
  129. See Documentation/power/video.txt
  130. acpi_sci= [HW,ACPI] ACPI System Control Interrupt trigger mode
  131. Format: { level | edge | high | low }
  132. acpi_irq_balance [HW,ACPI]
  133. ACPI will balance active IRQs
  134. default in APIC mode
  135. acpi_irq_nobalance [HW,ACPI]
  136. ACPI will not move active IRQs (default)
  137. default in PIC mode
  138. acpi_irq_pci= [HW,ACPI] If irq_balance, clear listed IRQs for
  139. use by PCI
  140. Format: <irq>,<irq>...
  141. acpi_irq_isa= [HW,ACPI] If irq_balance, mark listed IRQs used by ISA
  142. Format: <irq>,<irq>...
  143. acpi_os_name= [HW,ACPI] Tell ACPI BIOS the name of the OS
  144. Format: To spoof as Windows 98: ="Microsoft Windows"
  145. acpi_osi= [HW,ACPI] empty param disables _OSI
  146. acpi_serialize [HW,ACPI] force serialization of AML methods
  147. acpi_skip_timer_override [HW,ACPI]
  148. Recognize and ignore IRQ0/pin2 Interrupt Override.
  149. For broken nForce2 BIOS resulting in XT-PIC timer.
  150. acpi_use_timer_override [HW,ACPI}
  151. Use timer override. For some broken Nvidia NF5 boards
  152. that require a timer override, but don't have
  153. HPET
  154. acpi_dbg_layer= [HW,ACPI]
  155. Format: <int>
  156. Each bit of the <int> indicates an ACPI debug layer,
  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_layer.
  160. acpi_dbg_level= [HW,ACPI]
  161. Format: <int>
  162. Each bit of the <int> indicates an ACPI debug level,
  163. 1: enable, 0: disable. It is useful for boot time
  164. debugging. After system has booted up, it can be set
  165. via /proc/acpi/debug_level.
  166. acpi_fake_ecdt [HW,ACPI] Workaround failure due to BIOS lacking ECDT
  167. acpi_generic_hotkey [HW,ACPI]
  168. Allow consolidated generic hotkey driver to
  169. override platform specific driver.
  170. See also Documentation/acpi-hotkey.txt.
  171. acpi_pm_good [IA-32,X86-64]
  172. Override the pmtimer bug detection: force the kernel
  173. to assume that this machine's pmtimer latches its value
  174. and always returns good values.
  175. enable_timer_pin_1 [i386,x86-64]
  176. Enable PIN 1 of APIC timer
  177. Can be useful to work around chipset bugs
  178. (in particular on some ATI chipsets).
  179. The kernel tries to set a reasonable default.
  180. disable_timer_pin_1 [i386,x86-64]
  181. Disable PIN 1 of APIC timer
  182. Can be useful to work around chipset bugs.
  183. ad1816= [HW,OSS]
  184. Format: <io>,<irq>,<dma>,<dma2>
  185. See also Documentation/sound/oss/AD1816.
  186. ad1848= [HW,OSS]
  187. Format: <io>,<irq>,<dma>,<dma2>,<type>
  188. adlib= [HW,OSS]
  189. Format: <io>
  190. advansys= [HW,SCSI]
  191. See header of drivers/scsi/advansys.c.
  192. advwdt= [HW,WDT] Advantech WDT
  193. Format: <iostart>,<iostop>
  194. aedsp16= [HW,OSS] Audio Excel DSP 16
  195. Format: <io>,<irq>,<dma>,<mss_io>,<mpu_io>,<mpu_irq>
  196. See also header of sound/oss/aedsp16.c.
  197. aha152x= [HW,SCSI]
  198. See Documentation/scsi/aha152x.txt.
  199. aha1542= [HW,SCSI]
  200. Format: <portbase>[,<buson>,<busoff>[,<dmaspeed>]]
  201. aic7xxx= [HW,SCSI]
  202. See Documentation/scsi/aic7xxx.txt.
  203. aic79xx= [HW,SCSI]
  204. See Documentation/scsi/aic79xx.txt.
  205. amijoy.map= [HW,JOY] Amiga joystick support
  206. Map of devices attached to JOY0DAT and JOY1DAT
  207. Format: <a>,<b>
  208. See also Documentation/kernel/input/joystick.txt
  209. analog.map= [HW,JOY] Analog joystick and gamepad support
  210. Specifies type or capabilities of an analog joystick
  211. connected to one of 16 gameports
  212. Format: <type1>,<type2>,..<type16>
  213. apc= [HW,SPARC]
  214. Power management functions (SPARCstation-4/5 + deriv.)
  215. Format: noidle
  216. Disable APC CPU standby support. SPARCstation-Fox does
  217. not play well with APC CPU idle - disable it if you have
  218. APC and your system crashes randomly.
  219. apic= [APIC,i386] Change the output verbosity whilst booting
  220. Format: { quiet (default) | verbose | debug }
  221. Change the amount of debugging information output
  222. when initialising the APIC and IO-APIC components.
  223. apm= [APM] Advanced Power Management
  224. See header of arch/i386/kernel/apm.c.
  225. applicom= [HW]
  226. Format: <mem>,<irq>
  227. arcrimi= [HW,NET] ARCnet - "RIM I" (entirely mem-mapped) cards
  228. Format: <io>,<irq>,<nodeID>
  229. ataflop= [HW,M68k]
  230. atarimouse= [HW,MOUSE] Atari Mouse
  231. atascsi= [HW,SCSI] Atari SCSI
  232. atkbd.extra= [HW] Enable extra LEDs and keys on IBM RapidAccess,
  233. EzKey and similar keyboards
  234. atkbd.reset= [HW] Reset keyboard during initialization
  235. atkbd.set= [HW] Select keyboard code set
  236. Format: <int> (2 = AT (default), 3 = PS/2)
  237. atkbd.scroll= [HW] Enable scroll wheel on MS Office and similar
  238. keyboards
  239. atkbd.softraw= [HW] Choose between synthetic and real raw mode
  240. Format: <bool> (0 = real, 1 = synthetic (default))
  241. atkbd.softrepeat= [HW]
  242. Use software keyboard repeat
  243. autotest [IA64]
  244. aztcd= [HW,CD] Aztech CD268 CDROM driver
  245. Format: <io>,0x79 (?)
  246. baycom_epp= [HW,AX25]
  247. Format: <io>,<mode>
  248. baycom_par= [HW,AX25] BayCom Parallel Port AX.25 Modem
  249. Format: <io>,<mode>
  250. See header of drivers/net/hamradio/baycom_par.c.
  251. baycom_ser_fdx= [HW,AX25]
  252. BayCom Serial Port AX.25 Modem (Full Duplex Mode)
  253. Format: <io>,<irq>,<mode>[,<baud>]
  254. See header of drivers/net/hamradio/baycom_ser_fdx.c.
  255. baycom_ser_hdx= [HW,AX25]
  256. BayCom Serial Port AX.25 Modem (Half Duplex Mode)
  257. Format: <io>,<irq>,<mode>
  258. See header of drivers/net/hamradio/baycom_ser_hdx.c.
  259. blkmtd_device= [HW,MTD]
  260. blkmtd_erasesz=
  261. blkmtd_ro=
  262. blkmtd_bs=
  263. blkmtd_count=
  264. bttv.card= [HW,V4L] bttv (bt848 + bt878 based grabber cards)
  265. bttv.radio= Most important insmod options are available as
  266. kernel args too.
  267. bttv.pll= See Documentation/video4linux/bttv/Insmod-options
  268. bttv.tuner= and Documentation/video4linux/bttv/CARDLIST
  269. BusLogic= [HW,SCSI]
  270. See drivers/scsi/BusLogic.c, comment before function
  271. BusLogic_ParseDriverOptions().
  272. c101= [NET] Moxa C101 synchronous serial card
  273. cachesize= [BUGS=IA-32] Override level 2 CPU cache size detection.
  274. Sometimes CPU hardware bugs make them report the cache
  275. size incorrectly. The kernel will attempt work arounds
  276. to fix known problems, but for some CPUs it is not
  277. possible to determine what the correct size should be.
  278. This option provides an override for these situations.
  279. cdu31a= [HW,CD]
  280. Format: <io>,<irq>[,PAS]
  281. See header of drivers/cdrom/cdu31a.c.
  282. chandev= [HW,NET] Generic channel device initialisation
  283. checkreqprot [SELINUX] Set initial checkreqprot flag value.
  284. Format: { "0" | "1" }
  285. See security/selinux/Kconfig help text.
  286. 0 -- check protection applied by kernel (includes
  287. any implied execute protection).
  288. 1 -- check protection requested by application.
  289. Default value is set via a kernel config option.
  290. Value can be changed at runtime via
  291. /selinux/checkreqprot.
  292. clock= [BUGS=IA-32, HW] gettimeofday clocksource override.
  293. [Deprecated]
  294. Forces specified clocksource (if available) to be used
  295. when calculating gettimeofday(). If specified
  296. clocksource is not available, it defaults to PIT.
  297. Format: { pit | tsc | cyclone | pmtmr }
  298. code_bytes [IA32] How many bytes of object code to print in an
  299. oops report.
  300. Range: 0 - 8192
  301. Default: 64
  302. disable_8254_timer
  303. enable_8254_timer
  304. [IA32/X86_64] Disable/Enable interrupt 0 timer routing
  305. over the 8254 in addition to over the IO-APIC. The
  306. kernel tries to set a sensible default.
  307. hpet= [IA-32,HPET] option to disable HPET and use PIT.
  308. Format: disable
  309. cm206= [HW,CD]
  310. Format: { auto | [<io>,][<irq>] }
  311. com20020= [HW,NET] ARCnet - COM20020 chipset
  312. Format:
  313. <io>[,<irq>[,<nodeID>[,<backplane>[,<ckp>[,<timeout>]]]]]
  314. com90io= [HW,NET] ARCnet - COM90xx chipset (IO-mapped buffers)
  315. Format: <io>[,<irq>]
  316. com90xx= [HW,NET]
  317. ARCnet - COM90xx chipset (memory-mapped buffers)
  318. Format: <io>[,<irq>[,<memstart>]]
  319. condev= [HW,S390] console device
  320. conmode=
  321. console= [KNL] Output console device and options.
  322. tty<n> Use the virtual console device <n>.
  323. ttyS<n>[,options]
  324. ttyUSB0[,options]
  325. Use the specified serial port. The options are of
  326. the form "bbbbpnf", where "bbbb" is the baud rate,
  327. "p" is parity ("n", "o", or "e"), "n" is number of
  328. bits, and "f" is flow control ("r" for RTS or
  329. omit it). Default is "9600n8".
  330. See Documentation/serial-console.txt for more
  331. information. See
  332. Documentation/networking/netconsole.txt for an
  333. alternative.
  334. uart,io,<addr>[,options]
  335. uart,mmio,<addr>[,options]
  336. Start an early, polled-mode console on the 8250/16550
  337. UART at the specified I/O port or MMIO address,
  338. switching to the matching ttyS device later. The
  339. options are the same as for ttyS, above.
  340. cpcihp_generic= [HW,PCI] Generic port I/O CompactPCI driver
  341. Format:
  342. <first_slot>,<last_slot>,<port>,<enum_bit>[,<debug>]
  343. cpia_pp= [HW,PPT]
  344. Format: { parport<nr> | auto | none }
  345. crashkernel=nn[KMG]@ss[KMG]
  346. [KNL] Reserve a chunk of physical memory to
  347. hold a kernel to switch to with kexec on panic.
  348. cs4232= [HW,OSS]
  349. Format: <io>,<irq>,<dma>,<dma2>,<mpuio>,<mpuirq>
  350. cs89x0_dma= [HW,NET]
  351. Format: <dma>
  352. cs89x0_media= [HW,NET]
  353. Format: { rj45 | aui | bnc }
  354. cyclades= [HW,SERIAL] Cyclades multi-serial port adapter.
  355. dasd= [HW,NET]
  356. See header of drivers/s390/block/dasd_devmap.c.
  357. db9.dev[2|3]= [HW,JOY] Multisystem joystick support via parallel port
  358. (one device per port)
  359. Format: <port#>,<type>
  360. See also Documentation/input/joystick-parport.txt
  361. debug [KNL] Enable kernel debugging (events log level).
  362. debug_locks_verbose=
  363. [KNL] verbose self-tests
  364. Format=<0|1>
  365. Print debugging info while doing the locking API
  366. self-tests.
  367. We default to 0 (no extra messages), setting it to
  368. 1 will print _a lot_ more information - normally
  369. only useful to kernel developers.
  370. decnet= [HW,NET]
  371. Format: <area>[,<node>]
  372. See also Documentation/networking/decnet.txt.
  373. dhash_entries= [KNL]
  374. Set number of hash buckets for dentry cache.
  375. digi= [HW,SERIAL]
  376. IO parameters + enable/disable command.
  377. digiepca= [HW,SERIAL]
  378. See drivers/char/README.epca and
  379. Documentation/digiepca.txt.
  380. dmascc= [HW,AX25,SERIAL] AX.25 Z80SCC driver with DMA
  381. support available.
  382. Format: <io_dev0>[,<io_dev1>[,..<io_dev32>]]
  383. dmasound= [HW,OSS] Sound subsystem buffers
  384. dscc4.setup= [NET]
  385. dtc3181e= [HW,SCSI]
  386. earlyprintk= [IA-32,X86-64,SH]
  387. earlyprintk=vga
  388. earlyprintk=serial[,ttySn[,baudrate]]
  389. Append ",keep" to not disable it when the real console
  390. takes over.
  391. Only vga or serial at a time, not both.
  392. Currently only ttyS0 and ttyS1 are supported.
  393. Interaction with the standard serial driver is not
  394. very good.
  395. The VGA output is eventually overwritten by the real
  396. console.
  397. eata= [HW,SCSI]
  398. ec_intr= [HW,ACPI] ACPI Embedded Controller interrupt mode
  399. Format: <int>
  400. 0: polling mode
  401. non-0: interrupt mode (default)
  402. eda= [HW,PS2]
  403. edb= [HW,PS2]
  404. edd= [EDD]
  405. Format: {"of[f]" | "sk[ipmbr]"}
  406. See comment in arch/i386/boot/edd.S
  407. eicon= [HW,ISDN]
  408. Format: <id>,<membase>,<irq>
  409. eisa_irq_edge= [PARISC,HW]
  410. See header of drivers/parisc/eisa.c.
  411. elanfreq= [IA-32]
  412. See comment before function elanfreq_setup() in
  413. arch/i386/kernel/cpu/cpufreq/elanfreq.c.
  414. elevator= [IOSCHED]
  415. Format: {"anticipatory" | "cfq" | "deadline" | "noop"}
  416. See Documentation/block/as-iosched.txt and
  417. Documentation/block/deadline-iosched.txt for details.
  418. elfcorehdr= [IA-32, X86_64]
  419. Specifies physical address of start of kernel core
  420. image elf header. Generally kexec loader will
  421. pass this option to capture kernel.
  422. See Documentation/kdump/kdump.txt for details.
  423. enforcing [SELINUX] Set initial enforcing status.
  424. Format: {"0" | "1"}
  425. See security/selinux/Kconfig help text.
  426. 0 -- permissive (log only, no denials).
  427. 1 -- enforcing (deny and log).
  428. Default value is 0.
  429. Value can be changed at runtime via /selinux/enforce.
  430. es1371= [HW,OSS]
  431. Format: <spdif>,[<nomix>,[<amplifier>]]
  432. See also header of sound/oss/es1371.c.
  433. ether= [HW,NET] Ethernet cards parameters
  434. This option is obsoleted by the "netdev=" option, which
  435. has equivalent usage. See its documentation for details.
  436. eurwdt= [HW,WDT] Eurotech CPU-1220/1410 onboard watchdog.
  437. Format: <io>[,<irq>]
  438. failslab=
  439. fail_page_alloc=
  440. fail_make_request=[KNL]
  441. General fault injection mechanism.
  442. Format: <interval>,<probability>,<space>,<times>
  443. See also /Documentation/fault-injection/.
  444. fd_mcs= [HW,SCSI]
  445. See header of drivers/scsi/fd_mcs.c.
  446. fdomain= [HW,SCSI]
  447. See header of drivers/scsi/fdomain.c.
  448. floppy= [HW]
  449. See Documentation/floppy.txt.
  450. gamecon.map[2|3]=
  451. [HW,JOY] Multisystem joystick and NES/SNES/PSX pad
  452. support via parallel port (up to 5 devices per port)
  453. Format: <port#>,<pad1>,<pad2>,<pad3>,<pad4>,<pad5>
  454. See also Documentation/input/joystick-parport.txt
  455. gamma= [HW,DRM]
  456. gdth= [HW,SCSI]
  457. See header of drivers/scsi/gdth.c.
  458. gpt [EFI] Forces disk with valid GPT signature but
  459. invalid Protective MBR to be treated as GPT.
  460. gscd= [HW,CD]
  461. Format: <io>
  462. gvp11= [HW,SCSI]
  463. hashdist= [KNL,NUMA] Large hashes allocated during boot
  464. are distributed across NUMA nodes. Defaults on
  465. for IA-64, off otherwise.
  466. Format: 0 | 1 (for off | on)
  467. hcl= [IA-64] SGI's Hardware Graph compatibility layer
  468. hd= [EIDE] (E)IDE hard drive subsystem geometry
  469. Format: <cyl>,<head>,<sect>
  470. hd?= [HW] (E)IDE subsystem
  471. hd?lun= See Documentation/ide.txt.
  472. highmem=nn[KMG] [KNL,BOOT] forces the highmem zone to have an exact
  473. size of <nn>. This works even on boxes that have no
  474. highmem otherwise. This also works to reduce highmem
  475. size on bigger boxes.
  476. highres= [KNL] Enable/disable high resolution timer mode.
  477. Valid parameters: "on", "off"
  478. Default: "on"
  479. hisax= [HW,ISDN]
  480. See Documentation/isdn/README.HiSax.
  481. hugepages= [HW,IA-32,IA-64] Maximal number of HugeTLB pages.
  482. i8042.direct [HW] Put keyboard port into non-translated mode
  483. i8042.dumbkbd [HW] Pretend that controller can only read data from
  484. keyboard and cannot control its state
  485. (Don't attempt to blink the leds)
  486. i8042.noaux [HW] Don't check for auxiliary (== mouse) port
  487. i8042.nokbd [HW] Don't check/create keyboard port
  488. i8042.nomux [HW] Don't check presence of an active multiplexing
  489. controller
  490. i8042.nopnp [HW] Don't use ACPIPnP / PnPBIOS to discover KBD/AUX
  491. controllers
  492. i8042.panicblink=
  493. [HW] Frequency with which keyboard LEDs should blink
  494. when kernel panics (default is 0.5 sec)
  495. i8042.reset [HW] Reset the controller during init and cleanup
  496. i8042.unlock [HW] Unlock (ignore) the keylock
  497. i810= [HW,DRM]
  498. i8k.ignore_dmi [HW] Continue probing hardware even if DMI data
  499. indicates that the driver is running on unsupported
  500. hardware.
  501. i8k.force [HW] Activate i8k driver even if SMM BIOS signature
  502. does not match list of supported models.
  503. i8k.power_status
  504. [HW] Report power status in /proc/i8k
  505. (disabled by default)
  506. i8k.restricted [HW] Allow controlling fans only if SYS_ADMIN
  507. capability is set.
  508. ibmmcascsi= [HW,MCA,SCSI] IBM MicroChannel SCSI adapter
  509. See Documentation/mca.txt.
  510. icn= [HW,ISDN]
  511. Format: <io>[,<membase>[,<icn_id>[,<icn_id2>]]]
  512. ide= [HW] (E)IDE subsystem
  513. Format: ide=nodma or ide=doubler or ide=reverse
  514. See Documentation/ide.txt.
  515. ide?= [HW] (E)IDE subsystem
  516. Format: ide?=noprobe or chipset specific parameters.
  517. See Documentation/ide.txt.
  518. idebus= [HW] (E)IDE subsystem - VLB/PCI bus speed
  519. See Documentation/ide.txt.
  520. idle= [HW]
  521. Format: idle=poll or idle=halt
  522. ignore_loglevel [KNL]
  523. Ignore loglevel setting - this will print /all/
  524. kernel messages to the console. Useful for debugging.
  525. ihash_entries= [KNL]
  526. Set number of hash buckets for inode cache.
  527. in2000= [HW,SCSI]
  528. See header of drivers/scsi/in2000.c.
  529. init= [KNL]
  530. Format: <full_path>
  531. Run specified binary instead of /sbin/init as init
  532. process.
  533. initcall_debug [KNL] Trace initcalls as they are executed. Useful
  534. for working out where the kernel is dying during
  535. startup.
  536. initrd= [BOOT] Specify the location of the initial ramdisk
  537. inport.irq= [HW] Inport (ATI XL and Microsoft) busmouse driver
  538. Format: <irq>
  539. combined_mode= [HW] control which driver uses IDE ports in combined
  540. mode: legacy IDE driver, libata, or both
  541. (in the libata case, libata.atapi_enabled=1 may be
  542. useful as well). Note that using the ide or libata
  543. options may affect your device naming (e.g. by
  544. changing hdc to sdb).
  545. Format: combined (default), ide, or libata
  546. inttest= [IA64]
  547. io7= [HW] IO7 for Marvel based alpha systems
  548. See comment before marvel_specify_io7 in
  549. arch/alpha/kernel/core_marvel.c.
  550. ip= [IP_PNP]
  551. See Documentation/nfsroot.txt.
  552. ip2= [HW] Set IO/IRQ pairs for up to 4 IntelliPort boards
  553. See comment before ip2_setup() in drivers/char/ip2.c.
  554. ips= [HW,SCSI] Adaptec / IBM ServeRAID controller
  555. See header of drivers/scsi/ips.c.
  556. ports= [IP_VS_FTP] IPVS ftp helper module
  557. Default is 21.
  558. Up to 8 (IP_VS_APP_MAX_PORTS) ports
  559. may be specified.
  560. Format: <port>,<port>....
  561. irqfixup [HW]
  562. When an interrupt is not handled search all handlers
  563. for it. Intended to get systems with badly broken
  564. firmware running.
  565. irqpoll [HW]
  566. When an interrupt is not handled search all handlers
  567. for it. Also check all handlers each timer
  568. interrupt. Intended to get systems with badly broken
  569. firmware running.
  570. isapnp= [ISAPNP]
  571. Format: <RDP>,<reset>,<pci_scan>,<verbosity>
  572. isolcpus= [KNL,SMP] Isolate CPUs from the general scheduler.
  573. Format:
  574. <cpu number>,...,<cpu number>
  575. or
  576. <cpu number>-<cpu number> (must be a positive range in ascending order)
  577. or a mixture
  578. <cpu number>,...,<cpu number>-<cpu number>
  579. This option can be used to specify one or more CPUs
  580. to isolate from the general SMP balancing and scheduling
  581. algorithms. The only way to move a process onto or off
  582. an "isolated" CPU is via the CPU affinity syscalls.
  583. <cpu number> begins at 0 and the maximum value is
  584. "number of CPUs in system - 1".
  585. This option is the preferred way to isolate CPUs. The
  586. alternative -- manually setting the CPU mask of all
  587. tasks in the system -- can cause problems and
  588. suboptimal load balancer performance.
  589. isp16= [HW,CD]
  590. Format: <io>,<irq>,<dma>,<setup>
  591. iucv= [HW,NET]
  592. js= [HW,JOY] Analog joystick
  593. See Documentation/input/joystick.txt.
  594. keepinitrd [HW,ARM]
  595. kstack=N [IA-32,X86-64] Print N words from the kernel stack
  596. in oops dumps.
  597. l2cr= [PPC]
  598. lapic [IA-32,APIC] Enable the local APIC even if BIOS
  599. disabled it.
  600. lapic_timer_c2_ok [IA-32,x86-64,APIC] trust the local apic timer in
  601. C2 power state.
  602. lasi= [HW,SCSI] PARISC LASI driver for the 53c700 chip
  603. Format: addr:<io>,irq:<irq>
  604. llsc*= [IA64] See function print_params() in
  605. arch/ia64/sn/kernel/llsc4.c.
  606. load_ramdisk= [RAM] List of ramdisks to load from floppy
  607. See Documentation/ramdisk.txt.
  608. lockd.nlm_grace_period=P [NFS] Assign grace period.
  609. Format: <integer>
  610. lockd.nlm_tcpport=N [NFS] Assign TCP port.
  611. Format: <integer>
  612. lockd.nlm_timeout=T [NFS] Assign timeout value.
  613. Format: <integer>
  614. lockd.nlm_udpport=M [NFS] Assign UDP port.
  615. Format: <integer>
  616. logibm.irq= [HW,MOUSE] Logitech Bus Mouse Driver
  617. Format: <irq>
  618. loglevel= All Kernel Messages with a loglevel smaller than the
  619. console loglevel will be printed to the console. It can
  620. also be changed with klogd or other programs. The
  621. loglevels are defined as follows:
  622. 0 (KERN_EMERG) system is unusable
  623. 1 (KERN_ALERT) action must be taken immediately
  624. 2 (KERN_CRIT) critical conditions
  625. 3 (KERN_ERR) error conditions
  626. 4 (KERN_WARNING) warning conditions
  627. 5 (KERN_NOTICE) normal but significant condition
  628. 6 (KERN_INFO) informational
  629. 7 (KERN_DEBUG) debug-level messages
  630. log_buf_len=n Sets the size of the printk ring buffer, in bytes.
  631. Format: { n | nk | nM }
  632. n must be a power of two. The default size
  633. is set in the kernel config file.
  634. lp=0 [LP] Specify parallel ports to use, e.g,
  635. lp=port[,port...] lp=none,parport0 (lp0 not configured, lp1 uses
  636. lp=reset first parallel port). 'lp=0' disables the
  637. lp=auto printer driver. 'lp=reset' (which can be
  638. specified in addition to the ports) causes
  639. attached printers to be reset. Using
  640. lp=port1,port2,... specifies the parallel ports
  641. to associate lp devices with, starting with
  642. lp0. A port specification may be 'none' to skip
  643. that lp device, or a parport name such as
  644. 'parport0'. Specifying 'lp=auto' instead of a
  645. port specification list means that device IDs
  646. from each port should be examined, to see if
  647. an IEEE 1284-compliant printer is attached; if
  648. so, the driver will manage that printer.
  649. See also header of drivers/char/lp.c.
  650. lpj=n [KNL]
  651. Sets loops_per_jiffy to given constant, thus avoiding
  652. time-consuming boot-time autodetection (up to 250 ms per
  653. CPU). 0 enables autodetection (default). To determine
  654. the correct value for your kernel, boot with normal
  655. autodetection and see what value is printed. Note that
  656. on SMP systems the preset will be applied to all CPUs,
  657. which is likely to cause problems if your CPUs need
  658. significantly divergent settings. An incorrect value
  659. will cause delays in the kernel to be wrong, leading to
  660. unpredictable I/O errors and other breakage. Although
  661. unlikely, in the extreme case this might damage your
  662. hardware.
  663. ltpc= [NET]
  664. Format: <io>,<irq>,<dma>
  665. mac5380= [HW,SCSI] Format:
  666. <can_queue>,<cmd_per_lun>,<sg_tablesize>,<hostid>,<use_tags>
  667. mac53c9x= [HW,SCSI] Format:
  668. <num_esps>,<disconnect>,<nosync>,<can_queue>,<cmd_per_lun>,<sg_tablesize>,<hostid>,<use_tags>
  669. machvec= [IA64] Force the use of a particular machine-vector
  670. (machvec) in a generic kernel.
  671. Example: machvec=hpzx1_swiotlb
  672. max_loop= [LOOP] Maximum number of loopback devices that can
  673. be mounted
  674. Format: <1-256>
  675. maxcpus= [SMP] Maximum number of processors that an SMP kernel
  676. should make use of.
  677. Using "nosmp" or "maxcpus=0" will disable SMP
  678. entirely (the MPS table probe still happens, though).
  679. A command-line option of "maxcpus=<NUM>", where <NUM>
  680. is an integer greater than 0, limits the maximum number
  681. of CPUs activated in SMP mode to <NUM>.
  682. Using "maxcpus=1" on an SMP kernel is the trivial
  683. case of an SMP kernel with only one CPU.
  684. max_addr=[KMG] [KNL,BOOT,ia64] All physical memory greater than or
  685. equal to this physical address is ignored.
  686. max_luns= [SCSI] Maximum number of LUNs to probe.
  687. Should be between 1 and 2^32-1.
  688. max_report_luns=
  689. [SCSI] Maximum number of LUNs received.
  690. Should be between 1 and 16384.
  691. mca-pentium [BUGS=IA-32]
  692. mcatest= [IA-64]
  693. mcd= [HW,CD]
  694. Format: <port>,<irq>,<mitsumi_bug_93_wait>
  695. mcdx= [HW,CD]
  696. mce [IA-32] Machine Check Exception
  697. md= [HW] RAID subsystems devices and level
  698. See Documentation/md.txt.
  699. mdacon= [MDA]
  700. Format: <first>,<last>
  701. Specifies range of consoles to be captured by the MDA.
  702. mem=nn[KMG] [KNL,BOOT] Force usage of a specific amount of memory
  703. Amount of memory to be used when the kernel is not able
  704. to see the whole system memory or for test.
  705. [IA-32] Use together with memmap= to avoid physical
  706. address space collisions. Without memmap= PCI devices
  707. could be placed at addresses belonging to unused RAM.
  708. mem=nopentium [BUGS=IA-32] Disable usage of 4MB pages for kernel
  709. memory.
  710. memmap=exactmap [KNL,IA-32,X86_64] Enable setting of an exact
  711. E820 memory map, as specified by the user.
  712. Such memmap=exactmap lines can be constructed based on
  713. BIOS output or other requirements. See the memmap=nn@ss
  714. option description.
  715. memmap=nn[KMG]@ss[KMG]
  716. [KNL] Force usage of a specific region of memory
  717. Region of memory to be used, from ss to ss+nn.
  718. memmap=nn[KMG]#ss[KMG]
  719. [KNL,ACPI] Mark specific memory as ACPI data.
  720. Region of memory to be used, from ss to ss+nn.
  721. memmap=nn[KMG]$ss[KMG]
  722. [KNL,ACPI] Mark specific memory as reserved.
  723. Region of memory to be used, from ss to ss+nn.
  724. meye.*= [HW] Set MotionEye Camera parameters
  725. See Documentation/video4linux/meye.txt.
  726. mga= [HW,DRM]
  727. mousedev.tap_time=
  728. [MOUSE] Maximum time between finger touching and
  729. leaving touchpad surface for touch to be considered
  730. a tap and be reported as a left button click (for
  731. touchpads working in absolute mode only).
  732. Format: <msecs>
  733. mousedev.xres= [MOUSE] Horizontal screen resolution, used for devices
  734. reporting absolute coordinates, such as tablets
  735. mousedev.yres= [MOUSE] Vertical screen resolution, used for devices
  736. reporting absolute coordinates, such as tablets
  737. mpu401= [HW,OSS]
  738. Format: <io>,<irq>
  739. MTD_Partition= [MTD]
  740. Format: <name>,<region-number>,<size>,<offset>
  741. MTD_Region= [MTD] Format:
  742. <name>,<region-number>[,<base>,<size>,<buswidth>,<altbuswidth>]
  743. mtdparts= [MTD]
  744. See drivers/mtd/cmdline.c.
  745. mtouchusb.raw_coordinates=
  746. [HW] Make the MicroTouch USB driver use raw coordinates
  747. ('y', default) or cooked coordinates ('n')
  748. n2= [NET] SDL Inc. RISCom/N2 synchronous serial card
  749. NCR_D700= [HW,SCSI]
  750. See header of drivers/scsi/NCR_D700.c.
  751. ncr5380= [HW,SCSI]
  752. ncr53c400= [HW,SCSI]
  753. ncr53c400a= [HW,SCSI]
  754. ncr53c406a= [HW,SCSI]
  755. ncr53c8xx= [HW,SCSI]
  756. netdev= [NET] Network devices parameters
  757. Format: <irq>,<io>,<mem_start>,<mem_end>,<name>
  758. Note that mem_start is often overloaded to mean
  759. something different and driver-specific.
  760. This usage is only documented in each driver source
  761. file if at all.
  762. nfsaddrs= [NFS]
  763. See Documentation/nfsroot.txt.
  764. nfsroot= [NFS] nfs root filesystem for disk-less boxes.
  765. See Documentation/nfsroot.txt.
  766. nfs.callback_tcpport=
  767. [NFS] set the TCP port on which the NFSv4 callback
  768. channel should listen.
  769. nfs.idmap_cache_timeout=
  770. [NFS] set the maximum lifetime for idmapper cache
  771. entries.
  772. nmi_watchdog= [KNL,BUGS=IA-32] Debugging features for SMP kernels
  773. no387 [BUGS=IA-32] Tells the kernel to use the 387 maths
  774. emulation library even if a 387 maths coprocessor
  775. is present.
  776. noacpi [LIBATA] Disables use of ACPI in libata suspend/resume
  777. when set.
  778. Format: <int>
  779. noaliencache [MM, NUMA] Disables the allcoation of alien caches in
  780. the slab allocator. Saves per-node memory, but will
  781. impact performance on real NUMA hardware.
  782. noalign [KNL,ARM]
  783. noapic [SMP,APIC] Tells the kernel to not make use of any
  784. IOAPICs that may be present in the system.
  785. noasync [HW,M68K] Disables async and sync negotiation for
  786. all devices.
  787. nobats [PPC] Do not use BATs for mapping kernel lowmem
  788. on "Classic" PPC cores.
  789. nocache [ARM]
  790. nodelayacct [KNL] Disable per-task delay accounting
  791. nodisconnect [HW,SCSI,M68K] Disables SCSI disconnects.
  792. noexec [IA-64]
  793. noexec [IA-32,X86-64]
  794. noexec=on: enable non-executable mappings (default)
  795. noexec=off: disable nn-executable mappings
  796. nofxsr [BUGS=IA-32] Disables x86 floating point extended
  797. register save and restore. The kernel will only save
  798. legacy floating-point registers on task switch.
  799. nohlt [BUGS=ARM]
  800. no-hlt [BUGS=IA-32] Tells the kernel that the hlt
  801. instruction doesn't work correctly and not to
  802. use it.
  803. nohalt [IA-64] Tells the kernel not to use the power saving
  804. function PAL_HALT_LIGHT when idle. This increases
  805. power-consumption. On the positive side, it reduces
  806. interrupt wake-up latency, which may improve performance
  807. in certain environments such as networked servers or
  808. real-time systems.
  809. nohz= [KNL] Boottime enable/disable dynamic ticks
  810. Valid arguments: on, off
  811. Default: on
  812. noirqbalance [IA-32,SMP,KNL] Disable kernel irq balancing
  813. noirqdebug [IA-32] Disables the code which attempts to detect and
  814. disable unhandled interrupt sources.
  815. no_timer_check [IA-32,X86_64,APIC] Disables the code which tests for
  816. broken timer IRQ sources.
  817. noisapnp [ISAPNP] Disables ISA PnP code.
  818. noinitrd [RAM] Tells the kernel not to load any configured
  819. initial RAM disk.
  820. nointroute [IA-64]
  821. nolapic [IA-32,APIC] Do not enable or use the local APIC.
  822. nolapic_timer [IA-32,APIC] Do not use the local APIC timer.
  823. noltlbs [PPC] Do not use large page/tlb entries for kernel
  824. lowmem mapping on PPC40x.
  825. nomca [IA-64] Disable machine check abort handling
  826. nomce [IA-32] Machine Check Exception
  827. noresidual [PPC] Don't use residual data on PReP machines.
  828. noresume [SWSUSP] Disables resume and restores original swap
  829. space.
  830. no-scroll [VGA] Disables scrollback.
  831. This is required for the Braillex ib80-piezo Braille
  832. reader made by F.H. Papenmeier (Germany).
  833. nosbagart [IA-64]
  834. nosep [BUGS=IA-32] Disables x86 SYSENTER/SYSEXIT support.
  835. nosmp [SMP] Tells an SMP kernel to act as a UP kernel.
  836. nosync [HW,M68K] Disables sync negotiation for all devices.
  837. notsc [BUGS=IA-32] Disable Time Stamp Counter
  838. nousb [USB] Disable the USB subsystem
  839. nowb [ARM]
  840. nr_uarts= [SERIAL] maximum number of UARTs to be registered.
  841. opl3= [HW,OSS]
  842. Format: <io>
  843. opl3sa2= [HW,OSS] Format:
  844. <io>,<irq>,<dma>,<dma2>,<mss_io>,<mpu_io>,<ymode>,<loopback>[,<isapnp>,<multiple]
  845. oprofile.timer= [HW]
  846. Use timer interrupt instead of performance counters
  847. optcd= [HW,CD]
  848. Format: <io>
  849. osst= [HW,SCSI] SCSI Tape Driver
  850. Format: <buffer_size>,<write_threshold>
  851. See also Documentation/scsi/st.txt.
  852. panic= [KNL] Kernel behaviour on panic
  853. Format: <timeout>
  854. parkbd.port= [HW] Parallel port number the keyboard adapter is
  855. connected to, default is 0.
  856. Format: <parport#>
  857. parkbd.mode= [HW] Parallel port keyboard adapter mode of operation,
  858. 0 for XT, 1 for AT (default is AT).
  859. Format: <mode>
  860. parport= [HW,PPT] Specify parallel ports. 0 disables.
  861. Format: { 0 | auto | 0xBBB[,IRQ[,DMA]] }
  862. Use 'auto' to force the driver to use any
  863. IRQ/DMA settings detected (the default is to
  864. ignore detected IRQ/DMA settings because of
  865. possible conflicts). You can specify the base
  866. address, IRQ, and DMA settings; IRQ and DMA
  867. should be numbers, or 'auto' (for using detected
  868. settings on that particular port), or 'nofifo'
  869. (to avoid using a FIFO even if it is detected).
  870. Parallel ports are assigned in the order they
  871. are specified on the command line, starting
  872. with parport0.
  873. parport_init_mode= [HW,PPT]
  874. Configure VIA parallel port to operate in
  875. a specific mode. This is necessary on Pegasos
  876. computer where firmware has no options for setting
  877. up parallel port mode and sets it to spp.
  878. Currently this function knows 686a and 8231 chips.
  879. Format: [spp|ps2|epp|ecp|ecpepp]
  880. pas2= [HW,OSS] Format:
  881. <io>,<irq>,<dma>,<dma16>,<sb_io>,<sb_irq>,<sb_dma>,<sb_dma16>
  882. pas16= [HW,SCSI]
  883. See header of drivers/scsi/pas16.c.
  884. pause_on_oops=
  885. Halt all CPUs after the first oops has been printed for
  886. the specified number of seconds. This is to be used if
  887. your oopses keep scrolling off the screen.
  888. pcbit= [HW,ISDN]
  889. pcd. [PARIDE]
  890. See header of drivers/block/paride/pcd.c.
  891. See also Documentation/paride.txt.
  892. pci=option[,option...] [PCI] various PCI subsystem options:
  893. off [IA-32] don't probe for the PCI bus
  894. bios [IA-32] force use of PCI BIOS, don't access
  895. the hardware directly. Use this if your machine
  896. has a non-standard PCI host bridge.
  897. nobios [IA-32] disallow use of PCI BIOS, only direct
  898. hardware access methods are allowed. Use this
  899. if you experience crashes upon bootup and you
  900. suspect they are caused by the BIOS.
  901. conf1 [IA-32] Force use of PCI Configuration
  902. Mechanism 1.
  903. conf2 [IA-32] Force use of PCI Configuration
  904. Mechanism 2.
  905. nommconf [IA-32,X86_64] Disable use of MMCONFIG for PCI
  906. Configuration
  907. nomsi [MSI] If the PCI_MSI kernel config parameter is
  908. enabled, this kernel boot option can be used to
  909. disable the use of MSI interrupts system-wide.
  910. nosort [IA-32] Don't sort PCI devices according to
  911. order given by the PCI BIOS. This sorting is
  912. done to get a device order compatible with
  913. older kernels.
  914. biosirq [IA-32] Use PCI BIOS calls to get the interrupt
  915. routing table. These calls are known to be buggy
  916. on several machines and they hang the machine
  917. when used, but on other computers it's the only
  918. way to get the interrupt routing table. Try
  919. this option if the kernel is unable to allocate
  920. IRQs or discover secondary PCI buses on your
  921. motherboard.
  922. rom [IA-32] Assign address space to expansion ROMs.
  923. Use with caution as certain devices share
  924. address decoders between ROMs and other
  925. resources.
  926. irqmask=0xMMMM [IA-32] Set a bit mask of IRQs allowed to be
  927. assigned automatically to PCI devices. You can
  928. make the kernel exclude IRQs of your ISA cards
  929. this way.
  930. pirqaddr=0xAAAAA [IA-32] Specify the physical address
  931. of the PIRQ table (normally generated
  932. by the BIOS) if it is outside the
  933. F0000h-100000h range.
  934. lastbus=N [IA-32] Scan all buses thru bus #N. Can be
  935. useful if the kernel is unable to find your
  936. secondary buses and you want to tell it
  937. explicitly which ones they are.
  938. assign-busses [IA-32] Always assign all PCI bus
  939. numbers ourselves, overriding
  940. whatever the firmware may have done.
  941. usepirqmask [IA-32] Honor the possible IRQ mask stored
  942. in the BIOS $PIR table. This is needed on
  943. some systems with broken BIOSes, notably
  944. some HP Pavilion N5400 and Omnibook XE3
  945. notebooks. This will have no effect if ACPI
  946. IRQ routing is enabled.
  947. noacpi [IA-32] Do not use ACPI for IRQ routing
  948. or for PCI scanning.
  949. routeirq Do IRQ routing for all PCI devices.
  950. This is normally done in pci_enable_device(),
  951. so this option is a temporary workaround
  952. for broken drivers that don't call it.
  953. firmware [ARM] Do not re-enumerate the bus but instead
  954. just use the configuration from the
  955. bootloader. This is currently used on
  956. IXP2000 systems where the bus has to be
  957. configured a certain way for adjunct CPUs.
  958. noearly [X86] Don't do any early type 1 scanning.
  959. This might help on some broken boards which
  960. machine check when some devices' config space
  961. is read. But various workarounds are disabled
  962. and some IOMMU drivers will not work.
  963. bfsort Sort PCI devices into breadth-first order.
  964. This sorting is done to get a device
  965. order compatible with older (<= 2.4) kernels.
  966. nobfsort Don't sort PCI devices into breadth-first order.
  967. cbiosize=nn[KMG] The fixed amount of bus space which is
  968. reserved for the CardBus bridge's IO window.
  969. The default value is 256 bytes.
  970. cbmemsize=nn[KMG] The fixed amount of bus space which is
  971. reserved for the CardBus bridge's memory
  972. window. The default value is 64 megabytes.
  973. pcmv= [HW,PCMCIA] BadgePAD 4
  974. pd. [PARIDE]
  975. See Documentation/paride.txt.
  976. pdcchassis= [PARISC,HW] Disable/Enable PDC Chassis Status codes at
  977. boot time.
  978. Format: { 0 | 1 }
  979. See arch/parisc/kernel/pdc_chassis.c
  980. pf. [PARIDE]
  981. See Documentation/paride.txt.
  982. pg. [PARIDE]
  983. See Documentation/paride.txt.
  984. pirq= [SMP,APIC] Manual mp-table setup
  985. See Documentation/i386/IO-APIC.txt.
  986. plip= [PPT,NET] Parallel port network link
  987. Format: { parport<nr> | timid | 0 }
  988. See also Documentation/parport.txt.
  989. pnpacpi= [ACPI]
  990. { off }
  991. pnpbios= [ISAPNP]
  992. { on | off | curr | res | no-curr | no-res }
  993. pnp_reserve_irq=
  994. [ISAPNP] Exclude IRQs for the autoconfiguration
  995. pnp_reserve_dma=
  996. [ISAPNP] Exclude DMAs for the autoconfiguration
  997. pnp_reserve_io= [ISAPNP] Exclude I/O ports for the autoconfiguration
  998. Ranges are in pairs (I/O port base and size).
  999. pnp_reserve_mem=
  1000. [ISAPNP] Exclude memory regions for the
  1001. autoconfiguration.
  1002. Ranges are in pairs (memory base and size).
  1003. profile= [KNL] Enable kernel profiling via /proc/profile
  1004. Format: [schedule,]<number>
  1005. Param: "schedule" - profile schedule points.
  1006. Param: <number> - step/bucket size as a power of 2 for
  1007. statistical time based profiling.
  1008. Param: "sleep" - profile D-state sleeping (millisecs)
  1009. processor.max_cstate= [HW,ACPI]
  1010. Limit processor to maximum C-state
  1011. max_cstate=9 overrides any DMI blacklist limit.
  1012. processor.nocst [HW,ACPI]
  1013. Ignore the _CST method to determine C-states,
  1014. instead using the legacy FADT method
  1015. prompt_ramdisk= [RAM] List of RAM disks to prompt for floppy disk
  1016. before loading.
  1017. See Documentation/ramdisk.txt.
  1018. psmouse.proto= [HW,MOUSE] Highest PS2 mouse protocol extension to
  1019. probe for; one of (bare|imps|exps|lifebook|any).
  1020. psmouse.rate= [HW,MOUSE] Set desired mouse report rate, in reports
  1021. per second.
  1022. psmouse.resetafter= [HW,MOUSE]
  1023. Try to reset the device after so many bad packets
  1024. (0 = never).
  1025. psmouse.resolution=
  1026. [HW,MOUSE] Set desired mouse resolution, in dpi.
  1027. psmouse.smartscroll=
  1028. [HW,MOUSE] Controls Logitech smartscroll autorepeat.
  1029. 0 = disabled, 1 = enabled (default).
  1030. pss= [HW,OSS] Personal Sound System (ECHO ESC614)
  1031. Format:
  1032. <io>,<mss_io>,<mss_irq>,<mss_dma>,<mpu_io>,<mpu_irq>
  1033. pt. [PARIDE]
  1034. See Documentation/paride.txt.
  1035. quiet [KNL] Disable most log messages
  1036. r128= [HW,DRM]
  1037. raid= [HW,RAID]
  1038. See Documentation/md.txt.
  1039. ramdisk= [RAM] Sizes of RAM disks in kilobytes [deprecated]
  1040. See Documentation/ramdisk.txt.
  1041. ramdisk_blocksize= [RAM]
  1042. See Documentation/ramdisk.txt.
  1043. ramdisk_size= [RAM] Sizes of RAM disks in kilobytes
  1044. New name for the ramdisk parameter.
  1045. See Documentation/ramdisk.txt.
  1046. rcu.blimit= [KNL,BOOT] Set maximum number of finished
  1047. RCU callbacks to process in one batch.
  1048. rcu.qhimark= [KNL,BOOT] Set threshold of queued
  1049. RCU callbacks over which batch limiting is disabled.
  1050. rcu.qlowmark= [KNL,BOOT] Set threshold of queued
  1051. RCU callbacks below which batch limiting is re-enabled.
  1052. rdinit= [KNL]
  1053. Format: <full_path>
  1054. Run specified binary instead of /init from the ramdisk,
  1055. used for early userspace startup. See initrd.
  1056. reboot= [BUGS=IA-32,BUGS=ARM,BUGS=IA-64] Rebooting mode
  1057. Format: <reboot_mode>[,<reboot_mode2>[,...]]
  1058. See arch/*/kernel/reboot.c or arch/*/kernel/process.c
  1059. reserve= [KNL,BUGS] Force the kernel to ignore some iomem area
  1060. reservetop= [IA-32]
  1061. Format: nn[KMG]
  1062. Reserves a hole at the top of the kernel virtual
  1063. address space.
  1064. reset_devices [KNL] Force drivers to reset the underlying device
  1065. during initialization.
  1066. resume= [SWSUSP]
  1067. Specify the partition device for software suspend
  1068. resume_offset= [SWSUSP]
  1069. Specify the offset from the beginning of the partition
  1070. given by "resume=" at which the swap header is located,
  1071. in <PAGE_SIZE> units (needed only for swap files).
  1072. See Documentation/power/swsusp-and-swap-files.txt
  1073. retain_initrd [RAM] Keep initrd memory after extraction
  1074. rhash_entries= [KNL,NET]
  1075. Set number of hash buckets for route cache
  1076. riscom8= [HW,SERIAL]
  1077. Format: <io_board1>[,<io_board2>[,...<io_boardN>]]
  1078. ro [KNL] Mount root device read-only on boot
  1079. root= [KNL] Root filesystem
  1080. rootdelay= [KNL] Delay (in seconds) to pause before attempting to
  1081. mount the root filesystem
  1082. rootflags= [KNL] Set root filesystem mount option string
  1083. rootfstype= [KNL] Set root filesystem type
  1084. rw [KNL] Mount root device read-write on boot
  1085. S [KNL] Run init in single mode
  1086. sa1100ir [NET]
  1087. See drivers/net/irda/sa1100_ir.c.
  1088. sb= [HW,OSS]
  1089. Format: <io>,<irq>,<dma>,<dma2>
  1090. sbni= [NET] Granch SBNI12 leased line adapter
  1091. sbpcd= [HW,CD] Soundblaster CD adapter
  1092. Format: <io>,<type>
  1093. See a comment before function sbpcd_setup() in
  1094. drivers/cdrom/sbpcd.c.
  1095. sc1200wdt= [HW,WDT] SC1200 WDT (watchdog) driver
  1096. Format: <io>[,<timeout>[,<isapnp>]]
  1097. scsi_debug_*= [SCSI]
  1098. See drivers/scsi/scsi_debug.c.
  1099. scsi_default_dev_flags=
  1100. [SCSI] SCSI default device flags
  1101. Format: <integer>
  1102. scsi_dev_flags= [SCSI] Black/white list entry for vendor and model
  1103. Format: <vendor>:<model>:<flags>
  1104. (flags are integer value)
  1105. scsi_logging= [SCSI]
  1106. scsi_mod.scan= [SCSI] sync (default) scans SCSI busses as they are
  1107. discovered. async scans them in kernel threads,
  1108. allowing boot to proceed. none ignores them, expecting
  1109. user space to do the scan.
  1110. selinux [SELINUX] Disable or enable SELinux at boot time.
  1111. Format: { "0" | "1" }
  1112. See security/selinux/Kconfig help text.
  1113. 0 -- disable.
  1114. 1 -- enable.
  1115. Default value is set via kernel config option.
  1116. If enabled at boot time, /selinux/disable can be used
  1117. later to disable prior to initial policy load.
  1118. selinux_compat_net =
  1119. [SELINUX] Set initial selinux_compat_net flag value.
  1120. Format: { "0" | "1" }
  1121. 0 -- use new secmark-based packet controls
  1122. 1 -- use legacy packet controls
  1123. Default value is 0 (preferred).
  1124. Value can be changed at runtime via
  1125. /selinux/compat_net.
  1126. serialnumber [BUGS=IA-32]
  1127. sg_def_reserved_size= [SCSI]
  1128. shapers= [NET]
  1129. Maximal number of shapers.
  1130. sim710= [SCSI,HW]
  1131. See header of drivers/scsi/sim710.c.
  1132. simeth= [IA-64]
  1133. simscsi=
  1134. sjcd= [HW,CD]
  1135. Format: <io>,<irq>,<dma>
  1136. See header of drivers/cdrom/sjcd.c.
  1137. slram= [HW,MTD]
  1138. smart2= [HW]
  1139. Format: <io1>[,<io2>[,...,<io8>]]
  1140. snd-ad1816a= [HW,ALSA]
  1141. snd-ad1848= [HW,ALSA]
  1142. snd-ali5451= [HW,ALSA]
  1143. snd-als100= [HW,ALSA]
  1144. snd-als4000= [HW,ALSA]
  1145. snd-azt2320= [HW,ALSA]
  1146. snd-cmi8330= [HW,ALSA]
  1147. snd-cmipci= [HW,ALSA]
  1148. snd-cs4231= [HW,ALSA]
  1149. snd-cs4232= [HW,ALSA]
  1150. snd-cs4236= [HW,ALSA]
  1151. snd-cs4281= [HW,ALSA]
  1152. snd-cs46xx= [HW,ALSA]
  1153. snd-dt019x= [HW,ALSA]
  1154. snd-dummy= [HW,ALSA]
  1155. snd-emu10k1= [HW,ALSA]
  1156. snd-ens1370= [HW,ALSA]
  1157. snd-ens1371= [HW,ALSA]
  1158. snd-es968= [HW,ALSA]
  1159. snd-es1688= [HW,ALSA]
  1160. snd-es18xx= [HW,ALSA]
  1161. snd-es1938= [HW,ALSA]
  1162. snd-es1968= [HW,ALSA]
  1163. snd-fm801= [HW,ALSA]
  1164. snd-gusclassic= [HW,ALSA]
  1165. snd-gusextreme= [HW,ALSA]
  1166. snd-gusmax= [HW,ALSA]
  1167. snd-hdsp= [HW,ALSA]
  1168. snd-ice1712= [HW,ALSA]
  1169. snd-intel8x0= [HW,ALSA]
  1170. snd-interwave= [HW,ALSA]
  1171. snd-interwave-stb=
  1172. [HW,ALSA]
  1173. snd-korg1212= [HW,ALSA]
  1174. snd-maestro3= [HW,ALSA]
  1175. snd-mpu401= [HW,ALSA]
  1176. snd-mtpav= [HW,ALSA]
  1177. snd-nm256= [HW,ALSA]
  1178. snd-opl3sa2= [HW,ALSA]
  1179. snd-opti92x-ad1848=
  1180. [HW,ALSA]
  1181. snd-opti92x-cs4231=
  1182. [HW,ALSA]
  1183. snd-opti93x= [HW,ALSA]
  1184. snd-pmac= [HW,ALSA]
  1185. snd-rme32= [HW,ALSA]
  1186. snd-rme96= [HW,ALSA]
  1187. snd-rme9652= [HW,ALSA]
  1188. snd-sb8= [HW,ALSA]
  1189. snd-sb16= [HW,ALSA]
  1190. snd-sbawe= [HW,ALSA]
  1191. snd-serial= [HW,ALSA]
  1192. snd-sgalaxy= [HW,ALSA]
  1193. snd-sonicvibes= [HW,ALSA]
  1194. snd-sun-amd7930=
  1195. [HW,ALSA]
  1196. snd-sun-cs4231= [HW,ALSA]
  1197. snd-trident= [HW,ALSA]
  1198. snd-usb-audio= [HW,ALSA,USB]
  1199. snd-via82xx= [HW,ALSA]
  1200. snd-virmidi= [HW,ALSA]
  1201. snd-wavefront= [HW,ALSA]
  1202. snd-ymfpci= [HW,ALSA]
  1203. sonycd535= [HW,CD]
  1204. Format: <io>[,<irq>]
  1205. sonypi.*= [HW] Sony Programmable I/O Control Device driver
  1206. See Documentation/sonypi.txt
  1207. specialix= [HW,SERIAL] Specialix multi-serial port adapter
  1208. See Documentation/specialix.txt.
  1209. spia_io_base= [HW,MTD]
  1210. spia_fio_base=
  1211. spia_pedr=
  1212. spia_peddr=
  1213. sscape= [HW,OSS]
  1214. Format: <io>,<irq>,<dma>,<mpu_io>,<mpu_irq>
  1215. st= [HW,SCSI] SCSI tape parameters (buffers, etc.)
  1216. See Documentation/scsi/st.txt.
  1217. st0x= [HW,SCSI]
  1218. See header of drivers/scsi/seagate.c.
  1219. sti= [PARISC,HW]
  1220. Format: <num>
  1221. Set the STI (builtin display/keyboard on the HP-PARISC
  1222. machines) console (graphic card) which should be used
  1223. as the initial boot-console.
  1224. See also comment in drivers/video/console/sticore.c.
  1225. sti_font= [HW]
  1226. See comment in drivers/video/console/sticore.c.
  1227. stifb= [HW]
  1228. Format: bpp:<bpp1>[:<bpp2>[:<bpp3>...]]
  1229. sunrpc.pool_mode=
  1230. [NFS]
  1231. Control how the NFS server code allocates CPUs to
  1232. service thread pools. Depending on how many NICs
  1233. you have and where their interrupts are bound, this
  1234. option will affect which CPUs will do NFS serving.
  1235. Note: this parameter cannot be changed while the
  1236. NFS server is running.
  1237. auto the server chooses an appropriate mode
  1238. automatically using heuristics
  1239. global a single global pool contains all CPUs
  1240. percpu one pool for each CPU
  1241. pernode one pool for each NUMA node (equivalent
  1242. to global on non-NUMA machines)
  1243. swiotlb= [IA-64] Number of I/O TLB slabs
  1244. switches= [HW,M68k]
  1245. sym53c416= [HW,SCSI]
  1246. See header of drivers/scsi/sym53c416.c.
  1247. sysrq_always_enabled
  1248. [KNL]
  1249. Ignore sysrq setting - this boot parameter will
  1250. neutralize any effect of /proc/sys/kernel/sysrq.
  1251. Useful for debugging.
  1252. t128= [HW,SCSI]
  1253. See header of drivers/scsi/t128.c.
  1254. tdfx= [HW,DRM]
  1255. thash_entries= [KNL,NET]
  1256. Set number of hash buckets for TCP connection
  1257. time Show timing data prefixed to each printk message line
  1258. clocksource= [GENERIC_TIME] Override the default clocksource
  1259. Override the default clocksource and use the clocksource
  1260. with the name specified.
  1261. tipar.timeout= [HW,PPT]
  1262. Set communications timeout in tenths of a second
  1263. (default 15).
  1264. tipar.delay= [HW,PPT]
  1265. Set inter-bit delay in microseconds (default 10).
  1266. tmc8xx= [HW,SCSI]
  1267. See header of drivers/scsi/seagate.c.
  1268. tmscsim= [HW,SCSI]
  1269. See comment before function dc390_setup() in
  1270. drivers/scsi/tmscsim.c.
  1271. tp720= [HW,PS2]
  1272. trix= [HW,OSS] MediaTrix AudioTrix Pro
  1273. Format:
  1274. <io>,<irq>,<dma>,<dma2>,<sb_io>,<sb_irq>,<sb_dma>,<mpu_io>,<mpu_irq>
  1275. tsdev.xres= [TS] Horizontal screen resolution.
  1276. tsdev.yres= [TS] Vertical screen resolution.
  1277. turbografx.map[2|3]= [HW,JOY]
  1278. TurboGraFX parallel port interface
  1279. Format:
  1280. <port#>,<js1>,<js2>,<js3>,<js4>,<js5>,<js6>,<js7>
  1281. See also Documentation/input/joystick-parport.txt
  1282. u14-34f= [HW,SCSI] UltraStor 14F/34F SCSI host adapter
  1283. See header of drivers/scsi/u14-34f.c.
  1284. uart401= [HW,OSS]
  1285. Format: <io>,<irq>
  1286. uart6850= [HW,OSS]
  1287. Format: <io>,<irq>
  1288. uhci-hcd.ignore_oc=
  1289. [USB] Ignore overcurrent events (default N).
  1290. Some badly-designed motherboards generate lots of
  1291. bogus events, for ports that aren't wired to
  1292. anything. Set this parameter to avoid log spamming.
  1293. Note that genuine overcurrent events won't be
  1294. reported either.
  1295. usbcore.autosuspend=
  1296. [USB] The autosuspend time delay (in seconds) used
  1297. for newly-detected USB devices (default 2). This
  1298. is the time required before an idle device will be
  1299. autosuspended. Devices for which the delay is set
  1300. to 0 won't be autosuspended at all.
  1301. usbhid.mousepoll=
  1302. [USBHID] The interval which mice are to be polled at.
  1303. vdso= [IA-32,SH]
  1304. vdso=1: enable VDSO (default)
  1305. vdso=0: disable VDSO mapping
  1306. video= [FB] Frame buffer configuration
  1307. See Documentation/fb/modedb.txt.
  1308. vga= [BOOT,IA-32] Select a particular video mode
  1309. See Documentation/i386/boot.txt and
  1310. Documentation/svga.txt.
  1311. Use vga=ask for menu.
  1312. This is actually a boot loader parameter; the value is
  1313. passed to the kernel using a special protocol.
  1314. vmalloc=nn[KMG] [KNL,BOOT] Forces the vmalloc area to have an exact
  1315. size of <nn>. This can be used to increase the
  1316. minimum size (128MB on x86). It can also be used to
  1317. decrease the size and leave more room for directly
  1318. mapped kernel RAM.
  1319. vmhalt= [KNL,S390] Perform z/VM CP command after system halt.
  1320. Format: <command>
  1321. vmpanic= [KNL,S390] Perform z/VM CP command after kernel panic.
  1322. Format: <command>
  1323. vmpoff= [KNL,S390] Perform z/VM CP command after power off.
  1324. Format: <command>
  1325. waveartist= [HW,OSS]
  1326. Format: <io>,<irq>,<dma>,<dma2>
  1327. wd33c93= [HW,SCSI]
  1328. See header of drivers/scsi/wd33c93.c.
  1329. wd7000= [HW,SCSI]
  1330. See header of drivers/scsi/wd7000.c.
  1331. wdt= [WDT] Watchdog
  1332. See Documentation/watchdog/watchdog.txt.
  1333. xd= [HW,XT] Original XT pre-IDE (RLL encoded) disks.
  1334. xd_geo= See header of drivers/block/xd.c.
  1335. xirc2ps_cs= [NET,PCMCIA]
  1336. Format:
  1337. <irq>,<irq_mask>,<io>,<full_duplex>,<do_sound>,<lockup_hack>[,<irq2>[,<irq3>[,<irq4>]]]
  1338. norandmaps Don't use address space randomization
  1339. Equivalent to echo 0 > /proc/sys/kernel/randomize_va_space
  1340. unwind_debug=N N > 0 will enable dwarf2 unwinder debugging
  1341. This is useful to get more information why
  1342. you got a "dwarf2 unwinder stuck"
  1343. ______________________________________________________________________
  1344. TODO:
  1345. Add documentation for ALSA options.
  1346. Add more DRM drivers.