kernel-parameters.txt 48 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 text in square brackets at the beginning of the description states the
  21. restrictions on the kernel for the said kernel parameter to be valid. The
  22. restrictions referred to are that the relevant option is valid if:
  23. ACPI ACPI support is enabled.
  24. ALSA ALSA sound support is enabled.
  25. APIC APIC support is enabled.
  26. APM Advanced Power Management support is enabled.
  27. AX25 Appropriate AX.25 support is enabled.
  28. CD Appropriate CD support is enabled.
  29. DEVFS devfs support is enabled.
  30. DRM Direct Rendering Management support is enabled.
  31. EDD BIOS Enhanced Disk Drive Services (EDD) is enabled
  32. EFI EFI Partitioning (GPT) is enabled
  33. EIDE EIDE/ATAPI support is enabled.
  34. FB The frame buffer device is enabled.
  35. HW Appropriate hardware is enabled.
  36. IA-32 IA-32 aka i386 architecture is enabled.
  37. IA-64 IA-64 architecture is enabled.
  38. IOSCHED More than one I/O scheduler is enabled.
  39. IP_PNP IP DHCP, BOOTP, or RARP is enabled.
  40. ISAPNP ISA PnP code is enabled.
  41. ISDN Appropriate ISDN support is enabled.
  42. JOY Appropriate joystick support is enabled.
  43. LP Printer support is enabled.
  44. LOOP Loopback device support is enabled.
  45. M68k M68k architecture is enabled.
  46. These options have more detailed description inside of
  47. Documentation/m68k/kernel-options.txt.
  48. MCA MCA bus support is enabled.
  49. MDA MDA console support is enabled.
  50. MOUSE Appropriate mouse support is enabled.
  51. MSI Message Signaled Interrupts (PCI).
  52. MTD MTD support is enabled.
  53. NET Appropriate network support is enabled.
  54. NUMA NUMA support is enabled.
  55. NFS Appropriate NFS support is enabled.
  56. OSS OSS sound support is enabled.
  57. PARIDE The ParIDE subsystem is enabled.
  58. PARISC The PA-RISC architecture is enabled.
  59. PCI PCI bus support is enabled.
  60. PCMCIA The PCMCIA subsystem is enabled.
  61. PNP Plug & Play support is enabled.
  62. PPC PowerPC architecture is enabled.
  63. PPT Parallel port support is enabled.
  64. PS2 Appropriate PS/2 support is enabled.
  65. RAM RAM disk support is enabled.
  66. S390 S390 architecture is enabled.
  67. SCSI Appropriate SCSI support is enabled.
  68. A lot of drivers has their options described inside of
  69. Documentation/scsi/.
  70. SELINUX SELinux support is enabled.
  71. SERIAL Serial support is enabled.
  72. SMP The kernel is an SMP kernel.
  73. SPARC Sparc architecture is enabled.
  74. SWSUSP Software suspend is enabled.
  75. TS Appropriate touchscreen support is enabled.
  76. USB USB support is enabled.
  77. USBHID USB Human Interface Device support is enabled.
  78. V4L Video For Linux support is enabled.
  79. VGA The VGA console has been enabled.
  80. VT Virtual terminal support is enabled.
  81. WDT Watchdog support is enabled.
  82. XT IBM PC/XT MFM hard disk support is enabled.
  83. X86-64 X86-64 architecture is enabled.
  84. More X86-64 boot options can be found in
  85. Documentation/x86_64/boot-options.txt .
  86. In addition, the following text indicates that the option:
  87. BUGS= Relates to possible processor bugs on the said processor.
  88. KNL Is a kernel start-up parameter.
  89. BOOT Is a boot loader parameter.
  90. Parameters denoted with BOOT are actually interpreted by the boot
  91. loader, and have no meaning to the kernel directly.
  92. Do not modify the syntax of boot loader parameters without extreme
  93. need or coordination with <Documentation/i386/boot.txt>.
  94. Note that ALL kernel parameters listed below are CASE SENSITIVE, and that
  95. a trailing = on the name of any parameter states that that parameter will
  96. be entered as an environment variable, whereas its absence indicates that
  97. it will appear as a kernel argument readable via /proc/cmdline by programs
  98. running once the system is up.
  99. 53c7xx= [HW,SCSI] Amiga SCSI controllers
  100. See header of drivers/scsi/53c7xx.c.
  101. See also Documentation/scsi/ncr53c7xx.txt.
  102. acpi= [HW,ACPI] Advanced Configuration and Power Interface
  103. Format: { force | off | ht | strict | noirq }
  104. force -- enable ACPI if default was off
  105. off -- disable ACPI if default was on
  106. noirq -- do not use ACPI for IRQ routing
  107. ht -- run only enough ACPI to enable Hyper Threading
  108. strict -- Be less tolerant of platforms that are not
  109. strictly ACPI specification compliant.
  110. See also Documentation/pm.txt, pci=noacpi
  111. acpi_sleep= [HW,ACPI] Sleep options
  112. Format: { s3_bios, s3_mode }
  113. See Documentation/power/video.txt
  114. acpi_sci= [HW,ACPI] ACPI System Control Interrupt trigger mode
  115. Format: { level | edge | high | low }
  116. acpi_irq_balance [HW,ACPI]
  117. ACPI will balance active IRQs
  118. default in APIC mode
  119. acpi_irq_nobalance [HW,ACPI]
  120. ACPI will not move active IRQs (default)
  121. default in PIC mode
  122. acpi_irq_pci= [HW,ACPI] If irq_balance, clear listed IRQs for
  123. use by PCI
  124. Format: <irq>,<irq>...
  125. acpi_irq_isa= [HW,ACPI] If irq_balance, mark listed IRQs used by ISA
  126. Format: <irq>,<irq>...
  127. acpi_osi= [HW,ACPI] empty param disables _OSI
  128. acpi_serialize [HW,ACPI] force serialization of AML methods
  129. acpi_skip_timer_override [HW,ACPI]
  130. Recognize and ignore IRQ0/pin2 Interrupt Override.
  131. For broken nForce2 BIOS resulting in XT-PIC timer.
  132. acpi_dbg_layer= [HW,ACPI]
  133. Format: <int>
  134. Each bit of the <int> indicates an ACPI debug layer,
  135. 1: enable, 0: disable. It is useful for boot time
  136. debugging. After system has booted up, it can be set
  137. via /proc/acpi/debug_layer.
  138. acpi_dbg_level= [HW,ACPI]
  139. Format: <int>
  140. Each bit of the <int> indicates an ACPI debug level,
  141. 1: enable, 0: disable. It is useful for boot time
  142. debugging. After system has booted up, it can be set
  143. via /proc/acpi/debug_level.
  144. acpi_fake_ecdt [HW,ACPI] Workaround failure due to BIOS lacking ECDT
  145. acpi_generic_hotkey [HW,ACPI]
  146. Allow consolidated generic hotkey driver to
  147. override platform specific driver.
  148. See also Documentation/acpi-hotkey.txt.
  149. enable_timer_pin_1 [i386,x86-64]
  150. Enable PIN 1 of APIC timer
  151. Can be useful to work around chipset bugs
  152. (in particular on some ATI chipsets).
  153. The kernel tries to set a reasonable default.
  154. disable_timer_pin_1 [i386,x86-64]
  155. Disable PIN 1 of APIC timer
  156. Can be useful to work around chipset bugs.
  157. ad1816= [HW,OSS]
  158. Format: <io>,<irq>,<dma>,<dma2>
  159. See also Documentation/sound/oss/AD1816.
  160. ad1848= [HW,OSS]
  161. Format: <io>,<irq>,<dma>,<dma2>,<type>
  162. adlib= [HW,OSS]
  163. Format: <io>
  164. advansys= [HW,SCSI]
  165. See header of drivers/scsi/advansys.c.
  166. advwdt= [HW,WDT] Advantech WDT
  167. Format: <iostart>,<iostop>
  168. aedsp16= [HW,OSS] Audio Excel DSP 16
  169. Format: <io>,<irq>,<dma>,<mss_io>,<mpu_io>,<mpu_irq>
  170. See also header of sound/oss/aedsp16.c.
  171. aha152x= [HW,SCSI]
  172. See Documentation/scsi/aha152x.txt.
  173. aha1542= [HW,SCSI]
  174. Format: <portbase>[,<buson>,<busoff>[,<dmaspeed>]]
  175. aic7xxx= [HW,SCSI]
  176. See Documentation/scsi/aic7xxx.txt.
  177. aic79xx= [HW,SCSI]
  178. See Documentation/scsi/aic79xx.txt.
  179. amijoy.map= [HW,JOY] Amiga joystick support
  180. Map of devices attached to JOY0DAT and JOY1DAT
  181. Format: <a>,<b>
  182. See also Documentation/kernel/input/joystick.txt
  183. analog.map= [HW,JOY] Analog joystick and gamepad support
  184. Specifies type or capabilities of an analog joystick
  185. connected to one of 16 gameports
  186. Format: <type1>,<type2>,..<type16>
  187. apc= [HW,SPARC]
  188. Power management functions (SPARCstation-4/5 + deriv.)
  189. Format: noidle
  190. Disable APC CPU standby support. SPARCstation-Fox does
  191. not play well with APC CPU idle - disable it if you have
  192. APC and your system crashes randomly.
  193. apic= [APIC,i386] Change the output verbosity whilst booting
  194. Format: { quiet (default) | verbose | debug }
  195. Change the amount of debugging information output
  196. when initialising the APIC and IO-APIC components.
  197. apm= [APM] Advanced Power Management
  198. See header of arch/i386/kernel/apm.c.
  199. applicom= [HW]
  200. Format: <mem>,<irq>
  201. arcrimi= [HW,NET] ARCnet - "RIM I" (entirely mem-mapped) cards
  202. Format: <io>,<irq>,<nodeID>
  203. ataflop= [HW,M68k]
  204. atarimouse= [HW,MOUSE] Atari Mouse
  205. atascsi= [HW,SCSI] Atari SCSI
  206. atkbd.extra= [HW] Enable extra LEDs and keys on IBM RapidAccess,
  207. EzKey and similar keyboards
  208. atkbd.reset= [HW] Reset keyboard during initialization
  209. atkbd.set= [HW] Select keyboard code set
  210. Format: <int> (2 = AT (default), 3 = PS/2)
  211. atkbd.scroll= [HW] Enable scroll wheel on MS Office and similar
  212. keyboards
  213. atkbd.softraw= [HW] Choose between synthetic and real raw mode
  214. Format: <bool> (0 = real, 1 = synthetic (default))
  215. atkbd.softrepeat= [HW]
  216. Use software keyboard repeat
  217. autotest [IA64]
  218. awe= [HW,OSS] AWE32/SB32/AWE64 wave table synth
  219. Format: <io>,<memsize>,<isapnp>
  220. aztcd= [HW,CD] Aztech CD268 CDROM driver
  221. Format: <io>,0x79 (?)
  222. baycom_epp= [HW,AX25]
  223. Format: <io>,<mode>
  224. baycom_par= [HW,AX25] BayCom Parallel Port AX.25 Modem
  225. Format: <io>,<mode>
  226. See header of drivers/net/hamradio/baycom_par.c.
  227. baycom_ser_fdx= [HW,AX25]
  228. BayCom Serial Port AX.25 Modem (Full Duplex Mode)
  229. Format: <io>,<irq>,<mode>[,<baud>]
  230. See header of drivers/net/hamradio/baycom_ser_fdx.c.
  231. baycom_ser_hdx= [HW,AX25]
  232. BayCom Serial Port AX.25 Modem (Half Duplex Mode)
  233. Format: <io>,<irq>,<mode>
  234. See header of drivers/net/hamradio/baycom_ser_hdx.c.
  235. blkmtd_device= [HW,MTD]
  236. blkmtd_erasesz=
  237. blkmtd_ro=
  238. blkmtd_bs=
  239. blkmtd_count=
  240. bttv.card= [HW,V4L] bttv (bt848 + bt878 based grabber cards)
  241. bttv.radio= Most important insmod options are available as
  242. kernel args too.
  243. bttv.pll= See Documentation/video4linux/bttv/Insmod-options
  244. bttv.tuner= and Documentation/video4linux/bttv/CARDLIST
  245. BusLogic= [HW,SCSI]
  246. See drivers/scsi/BusLogic.c, comment before function
  247. BusLogic_ParseDriverOptions().
  248. c101= [NET] Moxa C101 synchronous serial card
  249. cachesize= [BUGS=IA-32] Override level 2 CPU cache size detection.
  250. Sometimes CPU hardware bugs make them report the cache
  251. size incorrectly. The kernel will attempt work arounds
  252. to fix known problems, but for some CPUs it is not
  253. possible to determine what the correct size should be.
  254. This option provides an override for these situations.
  255. cdu31a= [HW,CD]
  256. Format: <io>,<irq>[,PAS]
  257. See header of drivers/cdrom/cdu31a.c.
  258. chandev= [HW,NET] Generic channel device initialisation
  259. checkreqprot [SELINUX] Set initial checkreqprot flag value.
  260. Format: { "0" | "1" }
  261. See security/selinux/Kconfig help text.
  262. 0 -- check protection applied by kernel (includes
  263. any implied execute protection).
  264. 1 -- check protection requested by application.
  265. Default value is set via a kernel config option.
  266. Value can be changed at runtime via
  267. /selinux/checkreqprot.
  268. clock= [BUGS=IA-32,HW] gettimeofday timesource override.
  269. Forces specified timesource (if avaliable) to be used
  270. when calculating gettimeofday(). If specicified
  271. timesource is not avalible, it defaults to PIT.
  272. Format: { pit | tsc | cyclone | pmtmr }
  273. disable_8254_timer
  274. enable_8254_timer
  275. [IA32/X86_64] Disable/Enable interrupt 0 timer routing
  276. over the 8254 in addition to over the IO-APIC. The
  277. kernel tries to set a sensible default.
  278. hpet= [IA-32,HPET] option to disable HPET and use PIT.
  279. Format: disable
  280. cm206= [HW,CD]
  281. Format: { auto | [<io>,][<irq>] }
  282. com20020= [HW,NET] ARCnet - COM20020 chipset
  283. Format:
  284. <io>[,<irq>[,<nodeID>[,<backplane>[,<ckp>[,<timeout>]]]]]
  285. com90io= [HW,NET] ARCnet - COM90xx chipset (IO-mapped buffers)
  286. Format: <io>[,<irq>]
  287. com90xx= [HW,NET]
  288. ARCnet - COM90xx chipset (memory-mapped buffers)
  289. Format: <io>[,<irq>[,<memstart>]]
  290. condev= [HW,S390] console device
  291. conmode=
  292. console= [KNL] Output console device and options.
  293. tty<n> Use the virtual console device <n>.
  294. ttyS<n>[,options]
  295. ttyUSB0[,options]
  296. Use the specified serial port. The options are of
  297. the form "bbbbpnf", where "bbbb" is the baud rate,
  298. "p" is parity ("n", "o", or "e"), "n" is number of
  299. bits, and "f" is flow control ("r" for RTS or
  300. omit it). Default is "9600n8".
  301. See Documentation/serial-console.txt for more
  302. information. See
  303. Documentation/networking/netconsole.txt for an
  304. alternative.
  305. uart,io,<addr>[,options]
  306. uart,mmio,<addr>[,options]
  307. Start an early, polled-mode console on the 8250/16550
  308. UART at the specified I/O port or MMIO address,
  309. switching to the matching ttyS device later. The
  310. options are the same as for ttyS, above.
  311. cpcihp_generic= [HW,PCI] Generic port I/O CompactPCI driver
  312. Format:
  313. <first_slot>,<last_slot>,<port>,<enum_bit>[,<debug>]
  314. cpia_pp= [HW,PPT]
  315. Format: { parport<nr> | auto | none }
  316. crashkernel=nn[KMG]@ss[KMG]
  317. [KNL] Reserve a chunk of physical memory to
  318. hold a kernel to switch to with kexec on panic.
  319. cs4232= [HW,OSS]
  320. Format: <io>,<irq>,<dma>,<dma2>,<mpuio>,<mpuirq>
  321. cs89x0_dma= [HW,NET]
  322. Format: <dma>
  323. cs89x0_media= [HW,NET]
  324. Format: { rj45 | aui | bnc }
  325. cyclades= [HW,SERIAL] Cyclades multi-serial port adapter.
  326. dasd= [HW,NET]
  327. See header of drivers/s390/block/dasd_devmap.c.
  328. db9.dev[2|3]= [HW,JOY] Multisystem joystick support via parallel port
  329. (one device per port)
  330. Format: <port#>,<type>
  331. See also Documentation/input/joystick-parport.txt
  332. debug [KNL] Enable kernel debugging (events log level).
  333. decnet= [HW,NET]
  334. Format: <area>[,<node>]
  335. See also Documentation/networking/decnet.txt.
  336. devfs= [DEVFS]
  337. See Documentation/filesystems/devfs/boot-options.
  338. dhash_entries= [KNL]
  339. Set number of hash buckets for dentry cache.
  340. digi= [HW,SERIAL]
  341. IO parameters + enable/disable command.
  342. digiepca= [HW,SERIAL]
  343. See drivers/char/README.epca and
  344. Documentation/digiepca.txt.
  345. dmascc= [HW,AX25,SERIAL] AX.25 Z80SCC driver with DMA
  346. support available.
  347. Format: <io_dev0>[,<io_dev1>[,..<io_dev32>]]
  348. dmasound= [HW,OSS] Sound subsystem buffers
  349. dscc4.setup= [NET]
  350. dtc3181e= [HW,SCSI]
  351. earlyprintk= [IA-32,X86-64]
  352. earlyprintk=vga
  353. earlyprintk=serial[,ttySn[,baudrate]]
  354. Append ",keep" to not disable it when the real console
  355. takes over.
  356. Only vga or serial at a time, not both.
  357. Currently only ttyS0 and ttyS1 are supported.
  358. Interaction with the standard serial driver is not
  359. very good.
  360. The VGA output is eventually overwritten by the real
  361. console.
  362. eata= [HW,SCSI]
  363. ec_intr= [HW,ACPI] ACPI Embedded Controller interrupt mode
  364. Format: <int>
  365. 0: polling mode
  366. non-0: interrupt mode (default)
  367. eda= [HW,PS2]
  368. edb= [HW,PS2]
  369. edd= [EDD]
  370. Format: {"of[f]" | "sk[ipmbr]"}
  371. See comment in arch/i386/boot/edd.S
  372. eicon= [HW,ISDN]
  373. Format: <id>,<membase>,<irq>
  374. eisa_irq_edge= [PARISC,HW]
  375. See header of drivers/parisc/eisa.c.
  376. elanfreq= [IA-32]
  377. See comment before function elanfreq_setup() in
  378. arch/i386/kernel/cpu/cpufreq/elanfreq.c.
  379. elevator= [IOSCHED]
  380. Format: {"anticipatory" | "cfq" | "deadline" | "noop"}
  381. See Documentation/block/as-iosched.txt and
  382. Documentation/block/deadline-iosched.txt for details.
  383. elfcorehdr= [IA-32, X86_64]
  384. Specifies physical address of start of kernel core
  385. image elf header. Generally kexec loader will
  386. pass this option to capture kernel.
  387. See Documentation/kdump/kdump.txt for details.
  388. enforcing [SELINUX] Set initial enforcing status.
  389. Format: {"0" | "1"}
  390. See security/selinux/Kconfig help text.
  391. 0 -- permissive (log only, no denials).
  392. 1 -- enforcing (deny and log).
  393. Default value is 0.
  394. Value can be changed at runtime via /selinux/enforce.
  395. es1370= [HW,OSS]
  396. Format: <lineout>[,<micbias>]
  397. See also header of sound/oss/es1370.c.
  398. es1371= [HW,OSS]
  399. Format: <spdif>,[<nomix>,[<amplifier>]]
  400. See also header of sound/oss/es1371.c.
  401. ether= [HW,NET] Ethernet cards parameters
  402. This option is obsoleted by the "netdev=" option, which
  403. has equivalent usage. See its documentation for details.
  404. eurwdt= [HW,WDT] Eurotech CPU-1220/1410 onboard watchdog.
  405. Format: <io>[,<irq>]
  406. fd_mcs= [HW,SCSI]
  407. See header of drivers/scsi/fd_mcs.c.
  408. fdomain= [HW,SCSI]
  409. See header of drivers/scsi/fdomain.c.
  410. floppy= [HW]
  411. See Documentation/floppy.txt.
  412. ftape= [HW] Floppy Tape subsystem debugging options.
  413. See Documentation/ftape.txt.
  414. gamecon.map[2|3]=
  415. [HW,JOY] Multisystem joystick and NES/SNES/PSX pad
  416. support via parallel port (up to 5 devices per port)
  417. Format: <port#>,<pad1>,<pad2>,<pad3>,<pad4>,<pad5>
  418. See also Documentation/input/joystick-parport.txt
  419. gamma= [HW,DRM]
  420. gdth= [HW,SCSI]
  421. See header of drivers/scsi/gdth.c.
  422. gpt [EFI] Forces disk with valid GPT signature but
  423. invalid Protective MBR to be treated as GPT.
  424. gscd= [HW,CD]
  425. Format: <io>
  426. gt96100eth= [NET] MIPS GT96100 Advanced Communication Controller
  427. gus= [HW,OSS]
  428. Format: <io>,<irq>,<dma>,<dma16>
  429. gvp11= [HW,SCSI]
  430. hashdist= [KNL,NUMA] Large hashes allocated during boot
  431. are distributed across NUMA nodes. Defaults on
  432. for IA-64, off otherwise.
  433. Format: 0 | 1 (for off | on)
  434. hcl= [IA-64] SGI's Hardware Graph compatibility layer
  435. hd= [EIDE] (E)IDE hard drive subsystem geometry
  436. Format: <cyl>,<head>,<sect>
  437. hd?= [HW] (E)IDE subsystem
  438. hd?lun= See Documentation/ide.txt.
  439. highmem=nn[KMG] [KNL,BOOT] forces the highmem zone to have an exact
  440. size of <nn>. This works even on boxes that have no
  441. highmem otherwise. This also works to reduce highmem
  442. size on bigger boxes.
  443. hisax= [HW,ISDN]
  444. See Documentation/isdn/README.HiSax.
  445. hugepages= [HW,IA-32,IA-64] Maximal number of HugeTLB pages.
  446. noirqbalance [IA-32,SMP,KNL] Disable kernel irq balancing
  447. i8042.direct [HW] Put keyboard port into non-translated mode
  448. i8042.dumbkbd [HW] Pretend that controlled can only read data from
  449. keyboard and can not control its state
  450. (Don't attempt to blink the leds)
  451. i8042.noaux [HW] Don't check for auxiliary (== mouse) port
  452. i8042.nokbd [HW] Don't check/create keyboard port
  453. i8042.nomux [HW] Don't check presence of an active multiplexing
  454. controller
  455. i8042.nopnp [HW] Don't use ACPIPnP / PnPBIOS to discover KBD/AUX
  456. controllers
  457. i8042.panicblink=
  458. [HW] Frequency with which keyboard LEDs should blink
  459. when kernel panics (default is 0.5 sec)
  460. i8042.reset [HW] Reset the controller during init and cleanup
  461. i8042.unlock [HW] Unlock (ignore) the keylock
  462. i810= [HW,DRM]
  463. i8k.ignore_dmi [HW] Continue probing hardware even if DMI data
  464. indicates that the driver is running on unsupported
  465. hardware.
  466. i8k.force [HW] Activate i8k driver even if SMM BIOS signature
  467. does not match list of supported models.
  468. i8k.power_status
  469. [HW] Report power status in /proc/i8k
  470. (disabled by default)
  471. i8k.restricted [HW] Allow controlling fans only if SYS_ADMIN
  472. capability is set.
  473. ibmmcascsi= [HW,MCA,SCSI] IBM MicroChannel SCSI adapter
  474. See Documentation/mca.txt.
  475. icn= [HW,ISDN]
  476. Format: <io>[,<membase>[,<icn_id>[,<icn_id2>]]]
  477. ide= [HW] (E)IDE subsystem
  478. Format: ide=nodma or ide=doubler or ide=reverse
  479. See Documentation/ide.txt.
  480. ide?= [HW] (E)IDE subsystem
  481. Format: ide?=noprobe or chipset specific parameters.
  482. See Documentation/ide.txt.
  483. idebus= [HW] (E)IDE subsystem - VLB/PCI bus speed
  484. See Documentation/ide.txt.
  485. idle= [HW]
  486. Format: idle=poll or idle=halt
  487. ihash_entries= [KNL]
  488. Set number of hash buckets for inode cache.
  489. in2000= [HW,SCSI]
  490. See header of drivers/scsi/in2000.c.
  491. init= [KNL]
  492. Format: <full_path>
  493. Run specified binary instead of /sbin/init as init
  494. process.
  495. initcall_debug [KNL] Trace initcalls as they are executed. Useful
  496. for working out where the kernel is dying during
  497. startup.
  498. initrd= [BOOT] Specify the location of the initial ramdisk
  499. inport.irq= [HW] Inport (ATI XL and Microsoft) busmouse driver
  500. Format: <irq>
  501. combined_mode= [HW] control which driver uses IDE ports in combined
  502. mode: legacy IDE driver, libata, or both
  503. (in the libata case, libata.atapi_enabled=1 may be
  504. useful as well). Note that using the ide or libata
  505. options may affect your device naming (e.g. by
  506. changing hdc to sdb).
  507. Format: combined (default), ide, or libata
  508. inttest= [IA64]
  509. io7= [HW] IO7 for Marvel based alpha systems
  510. See comment before marvel_specify_io7 in
  511. arch/alpha/kernel/core_marvel.c.
  512. ip= [IP_PNP]
  513. See Documentation/nfsroot.txt.
  514. ip2= [HW] Set IO/IRQ pairs for up to 4 IntelliPort boards
  515. See comment before ip2_setup() in drivers/char/ip2.c.
  516. ips= [HW,SCSI] Adaptec / IBM ServeRAID controller
  517. See header of drivers/scsi/ips.c.
  518. irqfixup [HW]
  519. When an interrupt is not handled search all handlers
  520. for it. Intended to get systems with badly broken
  521. firmware running.
  522. irqpoll [HW]
  523. When an interrupt is not handled search all handlers
  524. for it. Also check all handlers each timer
  525. interrupt. Intended to get systems with badly broken
  526. firmware running.
  527. isapnp= [ISAPNP]
  528. Format: <RDP>,<reset>,<pci_scan>,<verbosity>
  529. isolcpus= [KNL,SMP] Isolate CPUs from the general scheduler.
  530. Format: <cpu number>,...,<cpu number>
  531. This option can be used to specify one or more CPUs
  532. to isolate from the general SMP balancing and scheduling
  533. algorithms. The only way to move a process onto or off
  534. an "isolated" CPU is via the CPU affinity syscalls.
  535. <cpu number> begins at 0 and the maximum value is
  536. "number of CPUs in system - 1".
  537. This option is the preferred way to isolate CPUs. The
  538. alternative -- manually setting the CPU mask of all
  539. tasks in the system -- can cause problems and
  540. suboptimal load balancer performance.
  541. isp16= [HW,CD]
  542. Format: <io>,<irq>,<dma>,<setup>
  543. iucv= [HW,NET]
  544. js= [HW,JOY] Analog joystick
  545. See Documentation/input/joystick.txt.
  546. keepinitrd [HW,ARM]
  547. kstack=N [IA-32,X86-64] Print N words from the kernel stack
  548. in oops dumps.
  549. l2cr= [PPC]
  550. lapic [IA-32,APIC] Enable the local APIC even if BIOS
  551. disabled it.
  552. lasi= [HW,SCSI] PARISC LASI driver for the 53c700 chip
  553. Format: addr:<io>,irq:<irq>
  554. llsc*= [IA64] See function print_params() in
  555. arch/ia64/sn/kernel/llsc4.c.
  556. load_ramdisk= [RAM] List of ramdisks to load from floppy
  557. See Documentation/ramdisk.txt.
  558. lockd.nlm_grace_period=P [NFS] Assign grace period.
  559. Format: <integer>
  560. lockd.nlm_tcpport=N [NFS] Assign TCP port.
  561. Format: <integer>
  562. lockd.nlm_timeout=T [NFS] Assign timeout value.
  563. Format: <integer>
  564. lockd.nlm_udpport=M [NFS] Assign UDP port.
  565. Format: <integer>
  566. logibm.irq= [HW,MOUSE] Logitech Bus Mouse Driver
  567. Format: <irq>
  568. loglevel= All Kernel Messages with a loglevel smaller than the
  569. console loglevel will be printed to the console. It can
  570. also be changed with klogd or other programs. The
  571. loglevels are defined as follows:
  572. 0 (KERN_EMERG) system is unusable
  573. 1 (KERN_ALERT) action must be taken immediately
  574. 2 (KERN_CRIT) critical conditions
  575. 3 (KERN_ERR) error conditions
  576. 4 (KERN_WARNING) warning conditions
  577. 5 (KERN_NOTICE) normal but significant condition
  578. 6 (KERN_INFO) informational
  579. 7 (KERN_DEBUG) debug-level messages
  580. log_buf_len=n Sets the size of the printk ring buffer, in bytes.
  581. Format: { n | nk | nM }
  582. n must be a power of two. The default size
  583. is set in the kernel config file.
  584. lp=0 [LP] Specify parallel ports to use, e.g,
  585. lp=port[,port...] lp=none,parport0 (lp0 not configured, lp1 uses
  586. lp=reset first parallel port). 'lp=0' disables the
  587. lp=auto printer driver. 'lp=reset' (which can be
  588. specified in addition to the ports) causes
  589. attached printers to be reset. Using
  590. lp=port1,port2,... specifies the parallel ports
  591. to associate lp devices with, starting with
  592. lp0. A port specification may be 'none' to skip
  593. that lp device, or a parport name such as
  594. 'parport0'. Specifying 'lp=auto' instead of a
  595. port specification list means that device IDs
  596. from each port should be examined, to see if
  597. an IEEE 1284-compliant printer is attached; if
  598. so, the driver will manage that printer.
  599. See also header of drivers/char/lp.c.
  600. lpj=n [KNL]
  601. Sets loops_per_jiffy to given constant, thus avoiding
  602. time-consuming boot-time autodetection (up to 250 ms per
  603. CPU). 0 enables autodetection (default). To determine
  604. the correct value for your kernel, boot with normal
  605. autodetection and see what value is printed. Note that
  606. on SMP systems the preset will be applied to all CPUs,
  607. which is likely to cause problems if your CPUs need
  608. significantly divergent settings. An incorrect value
  609. will cause delays in the kernel to be wrong, leading to
  610. unpredictable I/O errors and other breakage. Although
  611. unlikely, in the extreme case this might damage your
  612. hardware.
  613. ltpc= [NET]
  614. Format: <io>,<irq>,<dma>
  615. mac5380= [HW,SCSI] Format:
  616. <can_queue>,<cmd_per_lun>,<sg_tablesize>,<hostid>,<use_tags>
  617. mac53c9x= [HW,SCSI] Format:
  618. <num_esps>,<disconnect>,<nosync>,<can_queue>,<cmd_per_lun>,<sg_tablesize>,<hostid>,<use_tags>
  619. machvec= [IA64] Force the use of a particular machine-vector
  620. (machvec) in a generic kernel.
  621. Example: machvec=hpzx1_swiotlb
  622. mad16= [HW,OSS] Format:
  623. <io>,<irq>,<dma>,<dma16>,<mpu_io>,<mpu_irq>,<joystick>
  624. maui= [HW,OSS]
  625. Format: <io>,<irq>
  626. max_loop= [LOOP] Maximum number of loopback devices that can
  627. be mounted
  628. Format: <1-256>
  629. maxcpus= [SMP] Maximum number of processors that an SMP kernel
  630. should make use of
  631. max_addr=[KMG] [KNL,BOOT,ia64] All physical memory greater than or
  632. equal to this physical address is ignored.
  633. max_luns= [SCSI] Maximum number of LUNs to probe.
  634. Should be between 1 and 2^32-1.
  635. max_report_luns=
  636. [SCSI] Maximum number of LUNs received.
  637. Should be between 1 and 16384.
  638. mca-pentium [BUGS=IA-32]
  639. mcatest= [IA-64]
  640. mcd= [HW,CD]
  641. Format: <port>,<irq>,<mitsumi_bug_93_wait>
  642. mcdx= [HW,CD]
  643. mce [IA-32] Machine Check Exception
  644. md= [HW] RAID subsystems devices and level
  645. See Documentation/md.txt.
  646. mdacon= [MDA]
  647. Format: <first>,<last>
  648. Specifies range of consoles to be captured by the MDA.
  649. mem=nn[KMG] [KNL,BOOT] Force usage of a specific amount of memory
  650. Amount of memory to be used when the kernel is not able
  651. to see the whole system memory or for test.
  652. [IA-32] Use together with memmap= to avoid physical
  653. address space collisions. Without memmap= PCI devices
  654. could be placed at addresses belonging to unused RAM.
  655. mem=nopentium [BUGS=IA-32] Disable usage of 4MB pages for kernel
  656. memory.
  657. memmap=exactmap [KNL,IA-32,X86_64] Enable setting of an exact
  658. E820 memory map, as specified by the user.
  659. Such memmap=exactmap lines can be constructed based on
  660. BIOS output or other requirements. See the memmap=nn@ss
  661. option description.
  662. memmap=nn[KMG]@ss[KMG]
  663. [KNL] Force usage of a specific region of memory
  664. Region of memory to be used, from ss to ss+nn.
  665. memmap=nn[KMG]#ss[KMG]
  666. [KNL,ACPI] Mark specific memory as ACPI data.
  667. Region of memory to be used, from ss to ss+nn.
  668. memmap=nn[KMG]$ss[KMG]
  669. [KNL,ACPI] Mark specific memory as reserved.
  670. Region of memory to be used, from ss to ss+nn.
  671. meye.*= [HW] Set MotionEye Camera parameters
  672. See Documentation/video4linux/meye.txt.
  673. mga= [HW,DRM]
  674. migration_cost=
  675. [KNL,SMP] debug: override scheduler migration costs
  676. Format: <level-1-usecs>,<level-2-usecs>,...
  677. This debugging option can be used to override the
  678. default scheduler migration cost matrix. The numbers
  679. are indexed by 'CPU domain distance'.
  680. E.g. migration_cost=1000,2000,3000 on an SMT NUMA
  681. box will set up an intra-core migration cost of
  682. 1 msec, an inter-core migration cost of 2 msecs,
  683. and an inter-node migration cost of 3 msecs.
  684. WARNING: using the wrong values here can break
  685. scheduler performance, so it's only for scheduler
  686. development purposes, not production environments.
  687. migration_debug=
  688. [KNL,SMP] migration cost auto-detect verbosity
  689. Format=<0|1|2>
  690. If a system's migration matrix reported at bootup
  691. seems erroneous then this option can be used to
  692. increase verbosity of the detection process.
  693. We default to 0 (no extra messages), 1 will print
  694. some more information, and 2 will be really
  695. verbose (probably only useful if you also have a
  696. serial console attached to the system).
  697. migration_factor=
  698. [KNL,SMP] multiply/divide migration costs by a factor
  699. Format=<percent>
  700. This debug option can be used to proportionally
  701. increase or decrease the auto-detected migration
  702. costs for all entries of the migration matrix.
  703. E.g. migration_factor=150 will increase migration
  704. costs by 50%. (and thus the scheduler will be less
  705. eager migrating cache-hot tasks)
  706. migration_factor=80 will decrease migration costs
  707. by 20%. (thus the scheduler will be more eager to
  708. migrate tasks)
  709. WARNING: using the wrong values here can break
  710. scheduler performance, so it's only for scheduler
  711. development purposes, not production environments.
  712. mousedev.tap_time=
  713. [MOUSE] Maximum time between finger touching and
  714. leaving touchpad surface for touch to be considered
  715. a tap and be reported as a left button click (for
  716. touchpads working in absolute mode only).
  717. Format: <msecs>
  718. mousedev.xres= [MOUSE] Horizontal screen resolution, used for devices
  719. reporting absolute coordinates, such as tablets
  720. mousedev.yres= [MOUSE] Vertical screen resolution, used for devices
  721. reporting absolute coordinates, such as tablets
  722. mpu401= [HW,OSS]
  723. Format: <io>,<irq>
  724. MTD_Partition= [MTD]
  725. Format: <name>,<region-number>,<size>,<offset>
  726. MTD_Region= [MTD] Format:
  727. <name>,<region-number>[,<base>,<size>,<buswidth>,<altbuswidth>]
  728. mtdparts= [MTD]
  729. See drivers/mtd/cmdline.c.
  730. mtouchusb.raw_coordinates=
  731. [HW] Make the MicroTouch USB driver use raw coordinates
  732. ('y', default) or cooked coordinates ('n')
  733. n2= [NET] SDL Inc. RISCom/N2 synchronous serial card
  734. NCR_D700= [HW,SCSI]
  735. See header of drivers/scsi/NCR_D700.c.
  736. ncr5380= [HW,SCSI]
  737. ncr53c400= [HW,SCSI]
  738. ncr53c400a= [HW,SCSI]
  739. ncr53c406a= [HW,SCSI]
  740. ncr53c8xx= [HW,SCSI]
  741. netdev= [NET] Network devices parameters
  742. Format: <irq>,<io>,<mem_start>,<mem_end>,<name>
  743. Note that mem_start is often overloaded to mean
  744. something different and driver-specific.
  745. This usage is only documented in each driver source
  746. file if at all.
  747. nfsaddrs= [NFS]
  748. See Documentation/nfsroot.txt.
  749. nfsroot= [NFS] nfs root filesystem for disk-less boxes.
  750. See Documentation/nfsroot.txt.
  751. nfs.callback_tcpport=
  752. [NFS] set the TCP port on which the NFSv4 callback
  753. channel should listen.
  754. nfs.idmap_cache_timeout=
  755. [NFS] set the maximum lifetime for idmapper cache
  756. entries.
  757. nmi_watchdog= [KNL,BUGS=IA-32] Debugging features for SMP kernels
  758. no387 [BUGS=IA-32] Tells the kernel to use the 387 maths
  759. emulation library even if a 387 maths coprocessor
  760. is present.
  761. noalign [KNL,ARM]
  762. noapic [SMP,APIC] Tells the kernel to not make use of any
  763. IOAPICs that may be present in the system.
  764. noasync [HW,M68K] Disables async and sync negotiation for
  765. all devices.
  766. nobats [PPC] Do not use BATs for mapping kernel lowmem
  767. on "Classic" PPC cores.
  768. nocache [ARM]
  769. nodisconnect [HW,SCSI,M68K] Disables SCSI disconnects.
  770. noexec [IA-64]
  771. noexec [IA-32,X86-64]
  772. noexec=on: enable non-executable mappings (default)
  773. noexec=off: disable nn-executable mappings
  774. nofxsr [BUGS=IA-32] Disables x86 floating point extended
  775. register save and restore. The kernel will only save
  776. legacy floating-point registers on task switch.
  777. nohlt [BUGS=ARM]
  778. no-hlt [BUGS=IA-32] Tells the kernel that the hlt
  779. instruction doesn't work correctly and not to
  780. use it.
  781. nohalt [IA-64] Tells the kernel not to use the power saving
  782. function PAL_HALT_LIGHT when idle. This increases
  783. power-consumption. On the positive side, it reduces
  784. interrupt wake-up latency, which may improve performance
  785. in certain environments such as networked servers or
  786. real-time systems.
  787. noirqdebug [IA-32] Disables the code which attempts to detect and
  788. disable unhandled interrupt sources.
  789. noisapnp [ISAPNP] Disables ISA PnP code.
  790. noinitrd [RAM] Tells the kernel not to load any configured
  791. initial RAM disk.
  792. nointroute [IA-64]
  793. nolapic [IA-32,APIC] Do not enable or use the local APIC.
  794. noltlbs [PPC] Do not use large page/tlb entries for kernel
  795. lowmem mapping on PPC40x.
  796. nomca [IA-64] Disable machine check abort handling
  797. nomce [IA-32] Machine Check Exception
  798. noresidual [PPC] Don't use residual data on PReP machines.
  799. noresume [SWSUSP] Disables resume and restores original swap
  800. space.
  801. no-scroll [VGA] Disables scrollback.
  802. This is required for the Braillex ib80-piezo Braille
  803. reader made by F.H. Papenmeier (Germany).
  804. nosbagart [IA-64]
  805. nosep [BUGS=IA-32] Disables x86 SYSENTER/SYSEXIT support.
  806. nosmp [SMP] Tells an SMP kernel to act as a UP kernel.
  807. nosync [HW,M68K] Disables sync negotiation for all devices.
  808. notsc [BUGS=IA-32] Disable Time Stamp Counter
  809. nousb [USB] Disable the USB subsystem
  810. nowb [ARM]
  811. nr_uarts= [SERIAL] maximum number of UARTs to be registered.
  812. opl3= [HW,OSS]
  813. Format: <io>
  814. opl3sa= [HW,OSS]
  815. Format: <io>,<irq>,<dma>,<dma2>,<mpu_io>,<mpu_irq>
  816. opl3sa2= [HW,OSS] Format:
  817. <io>,<irq>,<dma>,<dma2>,<mss_io>,<mpu_io>,<ymode>,<loopback>[,<isapnp>,<multiple]
  818. oprofile.timer= [HW]
  819. Use timer interrupt instead of performance counters
  820. optcd= [HW,CD]
  821. Format: <io>
  822. osst= [HW,SCSI] SCSI Tape Driver
  823. Format: <buffer_size>,<write_threshold>
  824. See also Documentation/scsi/st.txt.
  825. panic= [KNL] Kernel behaviour on panic
  826. Format: <timeout>
  827. parkbd.port= [HW] Parallel port number the keyboard adapter is
  828. connected to, default is 0.
  829. Format: <parport#>
  830. parkbd.mode= [HW] Parallel port keyboard adapter mode of operation,
  831. 0 for XT, 1 for AT (default is AT).
  832. Format: <mode>
  833. parport= [HW,PPT] Specify parallel ports. 0 disables.
  834. Format: { 0 | auto | 0xBBB[,IRQ[,DMA]] }
  835. Use 'auto' to force the driver to use any
  836. IRQ/DMA settings detected (the default is to
  837. ignore detected IRQ/DMA settings because of
  838. possible conflicts). You can specify the base
  839. address, IRQ, and DMA settings; IRQ and DMA
  840. should be numbers, or 'auto' (for using detected
  841. settings on that particular port), or 'nofifo'
  842. (to avoid using a FIFO even if it is detected).
  843. Parallel ports are assigned in the order they
  844. are specified on the command line, starting
  845. with parport0.
  846. parport_init_mode= [HW,PPT]
  847. Configure VIA parallel port to operate in
  848. a specific mode. This is necessary on Pegasos
  849. computer where firmware has no options for setting
  850. up parallel port mode and sets it to spp.
  851. Currently this function knows 686a and 8231 chips.
  852. Format: [spp|ps2|epp|ecp|ecpepp]
  853. pas2= [HW,OSS] Format:
  854. <io>,<irq>,<dma>,<dma16>,<sb_io>,<sb_irq>,<sb_dma>,<sb_dma16>
  855. pas16= [HW,SCSI]
  856. See header of drivers/scsi/pas16.c.
  857. pause_on_oops=
  858. Halt all CPUs after the first oops has been printed for
  859. the specified number of seconds. This is to be used if
  860. your oopses keep scrolling off the screen.
  861. pcbit= [HW,ISDN]
  862. pcd. [PARIDE]
  863. See header of drivers/block/paride/pcd.c.
  864. See also Documentation/paride.txt.
  865. pci=option[,option...] [PCI] various PCI subsystem options:
  866. off [IA-32] don't probe for the PCI bus
  867. bios [IA-32] force use of PCI BIOS, don't access
  868. the hardware directly. Use this if your machine
  869. has a non-standard PCI host bridge.
  870. nobios [IA-32] disallow use of PCI BIOS, only direct
  871. hardware access methods are allowed. Use this
  872. if you experience crashes upon bootup and you
  873. suspect they are caused by the BIOS.
  874. conf1 [IA-32] Force use of PCI Configuration
  875. Mechanism 1.
  876. conf2 [IA-32] Force use of PCI Configuration
  877. Mechanism 2.
  878. nommconf [IA-32,X86_64] Disable use of MMCONFIG for PCI
  879. Configuration
  880. nomsi [MSI] If the PCI_MSI kernel config parameter is
  881. enabled, this kernel boot option can be used to
  882. disable the use of MSI interrupts system-wide.
  883. nosort [IA-32] Don't sort PCI devices according to
  884. order given by the PCI BIOS. This sorting is
  885. done to get a device order compatible with
  886. older kernels.
  887. biosirq [IA-32] Use PCI BIOS calls to get the interrupt
  888. routing table. These calls are known to be buggy
  889. on several machines and they hang the machine
  890. when used, but on other computers it's the only
  891. way to get the interrupt routing table. Try
  892. this option if the kernel is unable to allocate
  893. IRQs or discover secondary PCI buses on your
  894. motherboard.
  895. rom [IA-32] Assign address space to expansion ROMs.
  896. Use with caution as certain devices share
  897. address decoders between ROMs and other
  898. resources.
  899. irqmask=0xMMMM [IA-32] Set a bit mask of IRQs allowed to be
  900. assigned automatically to PCI devices. You can
  901. make the kernel exclude IRQs of your ISA cards
  902. this way.
  903. pirqaddr=0xAAAAA [IA-32] Specify the physical address
  904. of the PIRQ table (normally generated
  905. by the BIOS) if it is outside the
  906. F0000h-100000h range.
  907. lastbus=N [IA-32] Scan all buses thru bus #N. Can be
  908. useful if the kernel is unable to find your
  909. secondary buses and you want to tell it
  910. explicitly which ones they are.
  911. assign-busses [IA-32] Always assign all PCI bus
  912. numbers ourselves, overriding
  913. whatever the firmware may have done.
  914. usepirqmask [IA-32] Honor the possible IRQ mask stored
  915. in the BIOS $PIR table. This is needed on
  916. some systems with broken BIOSes, notably
  917. some HP Pavilion N5400 and Omnibook XE3
  918. notebooks. This will have no effect if ACPI
  919. IRQ routing is enabled.
  920. noacpi [IA-32] Do not use ACPI for IRQ routing
  921. or for PCI scanning.
  922. routeirq Do IRQ routing for all PCI devices.
  923. This is normally done in pci_enable_device(),
  924. so this option is a temporary workaround
  925. for broken drivers that don't call it.
  926. firmware [ARM] Do not re-enumerate the bus but instead
  927. just use the configuration from the
  928. bootloader. This is currently used on
  929. IXP2000 systems where the bus has to be
  930. configured a certain way for adjunct CPUs.
  931. pcmv= [HW,PCMCIA] BadgePAD 4
  932. pd. [PARIDE]
  933. See Documentation/paride.txt.
  934. pdcchassis= [PARISC,HW] Disable/Enable PDC Chassis Status codes at
  935. boot time.
  936. Format: { 0 | 1 }
  937. See arch/parisc/kernel/pdc_chassis.c
  938. pf. [PARIDE]
  939. See Documentation/paride.txt.
  940. pg. [PARIDE]
  941. See Documentation/paride.txt.
  942. pirq= [SMP,APIC] Manual mp-table setup
  943. See Documentation/i386/IO-APIC.txt.
  944. plip= [PPT,NET] Parallel port network link
  945. Format: { parport<nr> | timid | 0 }
  946. See also Documentation/parport.txt.
  947. pnpacpi= [ACPI]
  948. { off }
  949. pnpbios= [ISAPNP]
  950. { on | off | curr | res | no-curr | no-res }
  951. pnp_reserve_irq=
  952. [ISAPNP] Exclude IRQs for the autoconfiguration
  953. pnp_reserve_dma=
  954. [ISAPNP] Exclude DMAs for the autoconfiguration
  955. pnp_reserve_io= [ISAPNP] Exclude I/O ports for the autoconfiguration
  956. Ranges are in pairs (I/O port base and size).
  957. pnp_reserve_mem=
  958. [ISAPNP] Exclude memory regions for the
  959. autoconfiguration.
  960. Ranges are in pairs (memory base and size).
  961. profile= [KNL] Enable kernel profiling via /proc/profile
  962. Format: [schedule,]<number>
  963. Param: "schedule" - profile schedule points.
  964. Param: <number> - step/bucket size as a power of 2 for
  965. statistical time based profiling.
  966. processor.max_cstate= [HW,ACPI]
  967. Limit processor to maximum C-state
  968. max_cstate=9 overrides any DMI blacklist limit.
  969. processor.nocst [HW,ACPI]
  970. Ignore the _CST method to determine C-states,
  971. instead using the legacy FADT method
  972. prompt_ramdisk= [RAM] List of RAM disks to prompt for floppy disk
  973. before loading.
  974. See Documentation/ramdisk.txt.
  975. psmouse.proto= [HW,MOUSE] Highest PS2 mouse protocol extension to
  976. probe for; one of (bare|imps|exps|lifebook|any).
  977. psmouse.rate= [HW,MOUSE] Set desired mouse report rate, in reports
  978. per second.
  979. psmouse.resetafter= [HW,MOUSE]
  980. Try to reset the device after so many bad packets
  981. (0 = never).
  982. psmouse.resolution=
  983. [HW,MOUSE] Set desired mouse resolution, in dpi.
  984. psmouse.smartscroll=
  985. [HW,MOUSE] Controls Logitech smartscroll autorepeat.
  986. 0 = disabled, 1 = enabled (default).
  987. pss= [HW,OSS] Personal Sound System (ECHO ESC614)
  988. Format:
  989. <io>,<mss_io>,<mss_irq>,<mss_dma>,<mpu_io>,<mpu_irq>
  990. pt. [PARIDE]
  991. See Documentation/paride.txt.
  992. quiet= [KNL] Disable log messages
  993. r128= [HW,DRM]
  994. raid= [HW,RAID]
  995. See Documentation/md.txt.
  996. ramdisk= [RAM] Sizes of RAM disks in kilobytes [deprecated]
  997. See Documentation/ramdisk.txt.
  998. ramdisk_blocksize= [RAM]
  999. See Documentation/ramdisk.txt.
  1000. ramdisk_size= [RAM] Sizes of RAM disks in kilobytes
  1001. New name for the ramdisk parameter.
  1002. See Documentation/ramdisk.txt.
  1003. rcu.blimit= [KNL,BOOT] Set maximum number of finished
  1004. RCU callbacks to process in one batch.
  1005. rcu.qhimark= [KNL,BOOT] Set threshold of queued
  1006. RCU callbacks over which batch limiting is disabled.
  1007. rcu.qlowmark= [KNL,BOOT] Set threshold of queued
  1008. RCU callbacks below which batch limiting is re-enabled.
  1009. rcu.rsinterval= [KNL,BOOT,SMP] Set the number of additional
  1010. RCU callbacks to queued before forcing reschedule
  1011. on all cpus.
  1012. rdinit= [KNL]
  1013. Format: <full_path>
  1014. Run specified binary instead of /init from the ramdisk,
  1015. used for early userspace startup. See initrd.
  1016. reboot= [BUGS=IA-32,BUGS=ARM,BUGS=IA-64] Rebooting mode
  1017. Format: <reboot_mode>[,<reboot_mode2>[,...]]
  1018. See arch/*/kernel/reboot.c.
  1019. reserve= [KNL,BUGS] Force the kernel to ignore some iomem area
  1020. resume= [SWSUSP]
  1021. Specify the partition device for software suspend
  1022. rhash_entries= [KNL,NET]
  1023. Set number of hash buckets for route cache
  1024. riscom8= [HW,SERIAL]
  1025. Format: <io_board1>[,<io_board2>[,...<io_boardN>]]
  1026. ro [KNL] Mount root device read-only on boot
  1027. root= [KNL] Root filesystem
  1028. rootdelay= [KNL] Delay (in seconds) to pause before attempting to
  1029. mount the root filesystem
  1030. rootflags= [KNL] Set root filesystem mount option string
  1031. rootfstype= [KNL] Set root filesystem type
  1032. rw [KNL] Mount root device read-write on boot
  1033. S [KNL] Run init in single mode
  1034. sa1100ir [NET]
  1035. See drivers/net/irda/sa1100_ir.c.
  1036. sb= [HW,OSS]
  1037. Format: <io>,<irq>,<dma>,<dma2>
  1038. sbni= [NET] Granch SBNI12 leased line adapter
  1039. sbpcd= [HW,CD] Soundblaster CD adapter
  1040. Format: <io>,<type>
  1041. See a comment before function sbpcd_setup() in
  1042. drivers/cdrom/sbpcd.c.
  1043. sc1200wdt= [HW,WDT] SC1200 WDT (watchdog) driver
  1044. Format: <io>[,<timeout>[,<isapnp>]]
  1045. scsi_debug_*= [SCSI]
  1046. See drivers/scsi/scsi_debug.c.
  1047. scsi_default_dev_flags=
  1048. [SCSI] SCSI default device flags
  1049. Format: <integer>
  1050. scsi_dev_flags= [SCSI] Black/white list entry for vendor and model
  1051. Format: <vendor>:<model>:<flags>
  1052. (flags are integer value)
  1053. scsi_logging= [SCSI]
  1054. selinux [SELINUX] Disable or enable SELinux at boot time.
  1055. Format: { "0" | "1" }
  1056. See security/selinux/Kconfig help text.
  1057. 0 -- disable.
  1058. 1 -- enable.
  1059. Default value is set via kernel config option.
  1060. If enabled at boot time, /selinux/disable can be used
  1061. later to disable prior to initial policy load.
  1062. serialnumber [BUGS=IA-32]
  1063. sg_def_reserved_size= [SCSI]
  1064. sgalaxy= [HW,OSS]
  1065. Format: <io>,<irq>,<dma>,<dma2>,<sgbase>
  1066. shapers= [NET]
  1067. Maximal number of shapers.
  1068. sim710= [SCSI,HW]
  1069. See header of drivers/scsi/sim710.c.
  1070. simeth= [IA-64]
  1071. simscsi=
  1072. sjcd= [HW,CD]
  1073. Format: <io>,<irq>,<dma>
  1074. See header of drivers/cdrom/sjcd.c.
  1075. slram= [HW,MTD]
  1076. smart2= [HW]
  1077. Format: <io1>[,<io2>[,...,<io8>]]
  1078. snd-ad1816a= [HW,ALSA]
  1079. snd-ad1848= [HW,ALSA]
  1080. snd-ali5451= [HW,ALSA]
  1081. snd-als100= [HW,ALSA]
  1082. snd-als4000= [HW,ALSA]
  1083. snd-azt2320= [HW,ALSA]
  1084. snd-cmi8330= [HW,ALSA]
  1085. snd-cmipci= [HW,ALSA]
  1086. snd-cs4231= [HW,ALSA]
  1087. snd-cs4232= [HW,ALSA]
  1088. snd-cs4236= [HW,ALSA]
  1089. snd-cs4281= [HW,ALSA]
  1090. snd-cs46xx= [HW,ALSA]
  1091. snd-dt019x= [HW,ALSA]
  1092. snd-dummy= [HW,ALSA]
  1093. snd-emu10k1= [HW,ALSA]
  1094. snd-ens1370= [HW,ALSA]
  1095. snd-ens1371= [HW,ALSA]
  1096. snd-es968= [HW,ALSA]
  1097. snd-es1688= [HW,ALSA]
  1098. snd-es18xx= [HW,ALSA]
  1099. snd-es1938= [HW,ALSA]
  1100. snd-es1968= [HW,ALSA]
  1101. snd-fm801= [HW,ALSA]
  1102. snd-gusclassic= [HW,ALSA]
  1103. snd-gusextreme= [HW,ALSA]
  1104. snd-gusmax= [HW,ALSA]
  1105. snd-hdsp= [HW,ALSA]
  1106. snd-ice1712= [HW,ALSA]
  1107. snd-intel8x0= [HW,ALSA]
  1108. snd-interwave= [HW,ALSA]
  1109. snd-interwave-stb=
  1110. [HW,ALSA]
  1111. snd-korg1212= [HW,ALSA]
  1112. snd-maestro3= [HW,ALSA]
  1113. snd-mpu401= [HW,ALSA]
  1114. snd-mtpav= [HW,ALSA]
  1115. snd-nm256= [HW,ALSA]
  1116. snd-opl3sa2= [HW,ALSA]
  1117. snd-opti92x-ad1848=
  1118. [HW,ALSA]
  1119. snd-opti92x-cs4231=
  1120. [HW,ALSA]
  1121. snd-opti93x= [HW,ALSA]
  1122. snd-pmac= [HW,ALSA]
  1123. snd-rme32= [HW,ALSA]
  1124. snd-rme96= [HW,ALSA]
  1125. snd-rme9652= [HW,ALSA]
  1126. snd-sb8= [HW,ALSA]
  1127. snd-sb16= [HW,ALSA]
  1128. snd-sbawe= [HW,ALSA]
  1129. snd-serial= [HW,ALSA]
  1130. snd-sgalaxy= [HW,ALSA]
  1131. snd-sonicvibes= [HW,ALSA]
  1132. snd-sun-amd7930=
  1133. [HW,ALSA]
  1134. snd-sun-cs4231= [HW,ALSA]
  1135. snd-trident= [HW,ALSA]
  1136. snd-usb-audio= [HW,ALSA,USB]
  1137. snd-via82xx= [HW,ALSA]
  1138. snd-virmidi= [HW,ALSA]
  1139. snd-wavefront= [HW,ALSA]
  1140. snd-ymfpci= [HW,ALSA]
  1141. sonicvibes= [HW,OSS]
  1142. Format: <reverb>
  1143. sonycd535= [HW,CD]
  1144. Format: <io>[,<irq>]
  1145. sonypi.*= [HW] Sony Programmable I/O Control Device driver
  1146. See Documentation/sonypi.txt
  1147. specialix= [HW,SERIAL] Specialix multi-serial port adapter
  1148. See Documentation/specialix.txt.
  1149. spia_io_base= [HW,MTD]
  1150. spia_fio_base=
  1151. spia_pedr=
  1152. spia_peddr=
  1153. sscape= [HW,OSS]
  1154. Format: <io>,<irq>,<dma>,<mpu_io>,<mpu_irq>
  1155. st= [HW,SCSI] SCSI tape parameters (buffers, etc.)
  1156. See Documentation/scsi/st.txt.
  1157. st0x= [HW,SCSI]
  1158. See header of drivers/scsi/seagate.c.
  1159. sti= [PARISC,HW]
  1160. Format: <num>
  1161. Set the STI (builtin display/keyboard on the HP-PARISC
  1162. machines) console (graphic card) which should be used
  1163. as the initial boot-console.
  1164. See also comment in drivers/video/console/sticore.c.
  1165. sti_font= [HW]
  1166. See comment in drivers/video/console/sticore.c.
  1167. stifb= [HW]
  1168. Format: bpp:<bpp1>[:<bpp2>[:<bpp3>...]]
  1169. swiotlb= [IA-64] Number of I/O TLB slabs
  1170. switches= [HW,M68k]
  1171. sym53c416= [HW,SCSI]
  1172. See header of drivers/scsi/sym53c416.c.
  1173. t128= [HW,SCSI]
  1174. See header of drivers/scsi/t128.c.
  1175. tdfx= [HW,DRM]
  1176. thash_entries= [KNL,NET]
  1177. Set number of hash buckets for TCP connection
  1178. time Show timing data prefixed to each printk message line
  1179. tipar.timeout= [HW,PPT]
  1180. Set communications timeout in tenths of a second
  1181. (default 15).
  1182. tipar.delay= [HW,PPT]
  1183. Set inter-bit delay in microseconds (default 10).
  1184. tmc8xx= [HW,SCSI]
  1185. See header of drivers/scsi/seagate.c.
  1186. tmscsim= [HW,SCSI]
  1187. See comment before function dc390_setup() in
  1188. drivers/scsi/tmscsim.c.
  1189. tp720= [HW,PS2]
  1190. trix= [HW,OSS] MediaTrix AudioTrix Pro
  1191. Format:
  1192. <io>,<irq>,<dma>,<dma2>,<sb_io>,<sb_irq>,<sb_dma>,<mpu_io>,<mpu_irq>
  1193. tsdev.xres= [TS] Horizontal screen resolution.
  1194. tsdev.yres= [TS] Vertical screen resolution.
  1195. turbografx.map[2|3]= [HW,JOY]
  1196. TurboGraFX parallel port interface
  1197. Format:
  1198. <port#>,<js1>,<js2>,<js3>,<js4>,<js5>,<js6>,<js7>
  1199. See also Documentation/input/joystick-parport.txt
  1200. u14-34f= [HW,SCSI] UltraStor 14F/34F SCSI host adapter
  1201. See header of drivers/scsi/u14-34f.c.
  1202. uart401= [HW,OSS]
  1203. Format: <io>,<irq>
  1204. uart6850= [HW,OSS]
  1205. Format: <io>,<irq>
  1206. usbhid.mousepoll=
  1207. [USBHID] The interval which mice are to be polled at.
  1208. video= [FB] Frame buffer configuration
  1209. See Documentation/fb/modedb.txt.
  1210. vga= [BOOT,IA-32] Select a particular video mode
  1211. See Documentation/i386/boot.txt and
  1212. Documentation/svga.txt.
  1213. Use vga=ask for menu.
  1214. This is actually a boot loader parameter; the value is
  1215. passed to the kernel using a special protocol.
  1216. vmalloc=nn[KMG] [KNL,BOOT] Forces the vmalloc area to have an exact
  1217. size of <nn>. This can be used to increase the
  1218. minimum size (128MB on x86). It can also be used to
  1219. decrease the size and leave more room for directly
  1220. mapped kernel RAM.
  1221. vmhalt= [KNL,S390]
  1222. vmpoff= [KNL,S390]
  1223. waveartist= [HW,OSS]
  1224. Format: <io>,<irq>,<dma>,<dma2>
  1225. wd33c93= [HW,SCSI]
  1226. See header of drivers/scsi/wd33c93.c.
  1227. wd7000= [HW,SCSI]
  1228. See header of drivers/scsi/wd7000.c.
  1229. wdt= [WDT] Watchdog
  1230. See Documentation/watchdog/watchdog.txt.
  1231. xd= [HW,XT] Original XT pre-IDE (RLL encoded) disks.
  1232. xd_geo= See header of drivers/block/xd.c.
  1233. xirc2ps_cs= [NET,PCMCIA]
  1234. Format:
  1235. <irq>,<irq_mask>,<io>,<full_duplex>,<do_sound>,<lockup_hack>[,<irq2>[,<irq3>[,<irq4>]]]
  1236. norandmaps Don't use address space randomization
  1237. Equivalent to echo 0 > /proc/sys/kernel/randomize_va_space
  1238. ______________________________________________________________________
  1239. TODO:
  1240. Add documentation for ALSA options.
  1241. Add more DRM drivers.