kernel-parameters.txt 83 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. Hyphens (dashes) and underscores are equivalent in parameter names, so
  15. log_buf_len=1M print-fatal-signals=1
  16. can also be entered as
  17. log-buf-len=1M print_fatal_signals=1
  18. This document may not be entirely up to date and comprehensive. The command
  19. "modinfo -p ${modulename}" shows a current list of all parameters of a loadable
  20. module. Loadable modules, after being loaded into the running kernel, also
  21. reveal their parameters in /sys/module/${modulename}/parameters/. Some of these
  22. parameters may be changed at runtime by the command
  23. "echo -n ${value} > /sys/module/${modulename}/parameters/${parm}".
  24. The parameters listed below are only valid if certain kernel build options were
  25. enabled and if respective hardware is present. The text in square brackets at
  26. the beginning of each description states the restrictions within which a
  27. parameter is applicable:
  28. ACPI ACPI support is enabled.
  29. AGP AGP (Accelerated Graphics Port) is enabled.
  30. ALSA ALSA sound support is enabled.
  31. APIC APIC support is enabled.
  32. APM Advanced Power Management support is enabled.
  33. AVR32 AVR32 architecture is enabled.
  34. AX25 Appropriate AX.25 support is enabled.
  35. BLACKFIN Blackfin architecture is enabled.
  36. DRM Direct Rendering Management support is enabled.
  37. EDD BIOS Enhanced Disk Drive Services (EDD) is enabled
  38. EFI EFI Partitioning (GPT) is enabled
  39. EIDE EIDE/ATAPI support is enabled.
  40. FB The frame buffer device is enabled.
  41. HW Appropriate hardware is enabled.
  42. IA-64 IA-64 architecture is enabled.
  43. IMA Integrity measurement architecture is enabled.
  44. IOSCHED More than one I/O scheduler is enabled.
  45. IP_PNP IP DHCP, BOOTP, or RARP is enabled.
  46. ISAPNP ISA PnP code is enabled.
  47. ISDN Appropriate ISDN support is enabled.
  48. JOY Appropriate joystick support is enabled.
  49. LIBATA Libata driver is enabled
  50. LP Printer support is enabled.
  51. LOOP Loopback device support is enabled.
  52. M68k M68k architecture is enabled.
  53. These options have more detailed description inside of
  54. Documentation/m68k/kernel-options.txt.
  55. MCA MCA bus support is enabled.
  56. MDA MDA console support is enabled.
  57. MOUSE Appropriate mouse support is enabled.
  58. MSI Message Signaled Interrupts (PCI).
  59. MTD MTD (Memory Technology Device) support is enabled.
  60. NET Appropriate network support is enabled.
  61. NUMA NUMA support is enabled.
  62. GENERIC_TIME The generic timeofday code is enabled.
  63. NFS Appropriate NFS support is enabled.
  64. OSS OSS sound support is enabled.
  65. PV_OPS A paravirtualized kernel is enabled.
  66. PARIDE The ParIDE (parallel port IDE) subsystem is enabled.
  67. PARISC The PA-RISC architecture is enabled.
  68. PCI PCI bus support is enabled.
  69. PCIE PCI Express support is enabled.
  70. PCMCIA The PCMCIA subsystem is enabled.
  71. PNP Plug & Play support is enabled.
  72. PPC PowerPC architecture is enabled.
  73. PPT Parallel port support is enabled.
  74. PS2 Appropriate PS/2 support is enabled.
  75. RAM RAM disk support is enabled.
  76. ROOTPLUG The example Root Plug LSM is enabled.
  77. S390 S390 architecture is enabled.
  78. SCSI Appropriate SCSI support is enabled.
  79. A lot of drivers has their options described inside of
  80. Documentation/scsi/.
  81. SECURITY Different security models are enabled.
  82. SELINUX SELinux support is enabled.
  83. SERIAL Serial support is enabled.
  84. SH SuperH architecture is enabled.
  85. SMP The kernel is an SMP kernel.
  86. SPARC Sparc architecture is enabled.
  87. SWSUSP Software suspend (hibernation) is enabled.
  88. SUSPEND System suspend states are enabled.
  89. FTRACE Function tracing enabled.
  90. TS Appropriate touchscreen support is enabled.
  91. UMS USB Mass Storage support is enabled.
  92. USB USB support is enabled.
  93. USBHID USB Human Interface Device support is enabled.
  94. V4L Video For Linux support is enabled.
  95. VGA The VGA console has been enabled.
  96. VT Virtual terminal support is enabled.
  97. WDT Watchdog support is enabled.
  98. XT IBM PC/XT MFM hard disk support is enabled.
  99. X86-32 X86-32, aka i386 architecture is enabled.
  100. X86-64 X86-64 architecture is enabled.
  101. More X86-64 boot options can be found in
  102. Documentation/x86/x86_64/boot-options.txt .
  103. X86 Either 32bit or 64bit x86 (same as X86-32+X86-64)
  104. In addition, the following text indicates that the option:
  105. BUGS= Relates to possible processor bugs on the said processor.
  106. KNL Is a kernel start-up parameter.
  107. BOOT Is a boot loader parameter.
  108. Parameters denoted with BOOT are actually interpreted by the boot
  109. loader, and have no meaning to the kernel directly.
  110. Do not modify the syntax of boot loader parameters without extreme
  111. need or coordination with <Documentation/x86/boot.txt>.
  112. There are also arch-specific kernel-parameters not documented here.
  113. See for example <Documentation/x86/x86_64/boot-options.txt>.
  114. Note that ALL kernel parameters listed below are CASE SENSITIVE, and that
  115. a trailing = on the name of any parameter states that that parameter will
  116. be entered as an environment variable, whereas its absence indicates that
  117. it will appear as a kernel argument readable via /proc/cmdline by programs
  118. running once the system is up.
  119. The number of kernel parameters is not limited, but the length of the
  120. complete command line (parameters including spaces etc.) is limited to
  121. a fixed number of characters. This limit depends on the architecture
  122. and is between 256 and 4096 characters. It is defined in the file
  123. ./include/asm/setup.h as COMMAND_LINE_SIZE.
  124. acpi= [HW,ACPI,X86]
  125. Advanced Configuration and Power Interface
  126. Format: { force | off | ht | strict | noirq | rsdt }
  127. force -- enable ACPI if default was off
  128. off -- disable ACPI if default was on
  129. noirq -- do not use ACPI for IRQ routing
  130. ht -- run only enough ACPI to enable Hyper Threading
  131. strict -- Be less tolerant of platforms that are not
  132. strictly ACPI specification compliant.
  133. rsdt -- prefer RSDT over (default) XSDT
  134. See also Documentation/power/pm.txt, pci=noacpi
  135. acpi_apic_instance= [ACPI, IOAPIC]
  136. Format: <int>
  137. 2: use 2nd APIC table, if available
  138. 1,0: use 1st APIC table
  139. default: 0
  140. acpi_backlight= [HW,ACPI]
  141. acpi_backlight=vendor
  142. acpi_backlight=video
  143. If set to vendor, prefer vendor specific driver
  144. (e.g. thinkpad_acpi, sony_acpi, etc.) instead
  145. of the ACPI video.ko driver.
  146. acpi.debug_layer= [HW,ACPI,ACPI_DEBUG]
  147. acpi.debug_level= [HW,ACPI,ACPI_DEBUG]
  148. Format: <int>
  149. CONFIG_ACPI_DEBUG must be enabled to produce any ACPI
  150. debug output. Bits in debug_layer correspond to a
  151. _COMPONENT in an ACPI source file, e.g.,
  152. #define _COMPONENT ACPI_PCI_COMPONENT
  153. Bits in debug_level correspond to a level in
  154. ACPI_DEBUG_PRINT statements, e.g.,
  155. ACPI_DEBUG_PRINT((ACPI_DB_INFO, ...
  156. The debug_level mask defaults to "info". See
  157. Documentation/acpi/debug.txt for more information about
  158. debug layers and levels.
  159. Enable processor driver info messages:
  160. acpi.debug_layer=0x20000000
  161. Enable PCI/PCI interrupt routing info messages:
  162. acpi.debug_layer=0x400000
  163. Enable AML "Debug" output, i.e., stores to the Debug
  164. object while interpreting AML:
  165. acpi.debug_layer=0xffffffff acpi.debug_level=0x2
  166. Enable all messages related to ACPI hardware:
  167. acpi.debug_layer=0x2 acpi.debug_level=0xffffffff
  168. Some values produce so much output that the system is
  169. unusable. The "log_buf_len" parameter may be useful
  170. if you need to capture more output.
  171. acpi_display_output= [HW,ACPI]
  172. acpi_display_output=vendor
  173. acpi_display_output=video
  174. See above.
  175. acpi_irq_balance [HW,ACPI]
  176. ACPI will balance active IRQs
  177. default in APIC mode
  178. acpi_irq_nobalance [HW,ACPI]
  179. ACPI will not move active IRQs (default)
  180. default in PIC mode
  181. acpi_irq_isa= [HW,ACPI] If irq_balance, mark listed IRQs used by ISA
  182. Format: <irq>,<irq>...
  183. acpi_irq_pci= [HW,ACPI] If irq_balance, clear listed IRQs for
  184. use by PCI
  185. Format: <irq>,<irq>...
  186. acpi_no_auto_ssdt [HW,ACPI] Disable automatic loading of SSDT
  187. acpi_os_name= [HW,ACPI] Tell ACPI BIOS the name of the OS
  188. Format: To spoof as Windows 98: ="Microsoft Windows"
  189. acpi_osi= [HW,ACPI] Modify list of supported OS interface strings
  190. acpi_osi="string1" # add string1 -- only one string
  191. acpi_osi="!string2" # remove built-in string2
  192. acpi_osi= # disable all strings
  193. acpi_pm_good [X86]
  194. Override the pmtimer bug detection: force the kernel
  195. to assume that this machine's pmtimer latches its value
  196. and always returns good values.
  197. acpi.power_nocheck= [HW,ACPI]
  198. Format: 1/0 enable/disable the check of power state.
  199. On some bogus BIOS the _PSC object/_STA object of
  200. power resource can't return the correct device power
  201. state. In such case it is unneccessary to check its
  202. power state again in power transition.
  203. 1 : disable the power state check
  204. acpi_sci= [HW,ACPI] ACPI System Control Interrupt trigger mode
  205. Format: { level | edge | high | low }
  206. acpi_serialize [HW,ACPI] force serialization of AML methods
  207. acpi_skip_timer_override [HW,ACPI]
  208. Recognize and ignore IRQ0/pin2 Interrupt Override.
  209. For broken nForce2 BIOS resulting in XT-PIC timer.
  210. acpi_sleep= [HW,ACPI] Sleep options
  211. Format: { s3_bios, s3_mode, s3_beep, s4_nohwsig,
  212. old_ordering, s4_nonvs }
  213. See Documentation/power/video.txt for information on
  214. s3_bios and s3_mode.
  215. s3_beep is for debugging; it makes the PC's speaker beep
  216. as soon as the kernel's real-mode entry point is called.
  217. s4_nohwsig prevents ACPI hardware signature from being
  218. used during resume from hibernation.
  219. old_ordering causes the ACPI 1.0 ordering of the _PTS
  220. control method, with respect to putting devices into
  221. low power states, to be enforced (the ACPI 2.0 ordering
  222. of _PTS is used by default).
  223. s4_nonvs prevents the kernel from saving/restoring the
  224. ACPI NVS memory during hibernation.
  225. acpi_use_timer_override [HW,ACPI]
  226. Use timer override. For some broken Nvidia NF5 boards
  227. that require a timer override, but don't have HPET
  228. acpi_enforce_resources= [ACPI]
  229. { strict | lax | no }
  230. Check for resource conflicts between native drivers
  231. and ACPI OperationRegions (SystemIO and SystemMemory
  232. only). IO ports and memory declared in ACPI might be
  233. used by the ACPI subsystem in arbitrary AML code and
  234. can interfere with legacy drivers.
  235. strict (default): access to resources claimed by ACPI
  236. is denied; legacy drivers trying to access reserved
  237. resources will fail to bind to device using them.
  238. lax: access to resources claimed by ACPI is allowed;
  239. legacy drivers trying to access reserved resources
  240. will bind successfully but a warning message is logged.
  241. no: ACPI OperationRegions are not marked as reserved,
  242. no further checks are performed.
  243. ad1848= [HW,OSS]
  244. Format: <io>,<irq>,<dma>,<dma2>,<type>
  245. add_efi_memmap [EFI; X86] Include EFI memory map in
  246. kernel's map of available physical RAM.
  247. advansys= [HW,SCSI]
  248. See header of drivers/scsi/advansys.c.
  249. advwdt= [HW,WDT] Advantech WDT
  250. Format: <iostart>,<iostop>
  251. aedsp16= [HW,OSS] Audio Excel DSP 16
  252. Format: <io>,<irq>,<dma>,<mss_io>,<mpu_io>,<mpu_irq>
  253. See also header of sound/oss/aedsp16.c.
  254. agp= [AGP]
  255. { off | try_unsupported }
  256. off: disable AGP support
  257. try_unsupported: try to drive unsupported chipsets
  258. (may crash computer or cause data corruption)
  259. aha152x= [HW,SCSI]
  260. See Documentation/scsi/aha152x.txt.
  261. aha1542= [HW,SCSI]
  262. Format: <portbase>[,<buson>,<busoff>[,<dmaspeed>]]
  263. aic7xxx= [HW,SCSI]
  264. See Documentation/scsi/aic7xxx.txt.
  265. aic79xx= [HW,SCSI]
  266. See Documentation/scsi/aic79xx.txt.
  267. amd_iommu= [HW,X86-84]
  268. Pass parameters to the AMD IOMMU driver in the system.
  269. Possible values are:
  270. isolate - enable device isolation (each device, as far
  271. as possible, will get its own protection
  272. domain) [default]
  273. share - put every device behind one IOMMU into the
  274. same protection domain
  275. fullflush - enable flushing of IO/TLB entries when
  276. they are unmapped. Otherwise they are
  277. flushed before they will be reused, which
  278. is a lot of faster
  279. amijoy.map= [HW,JOY] Amiga joystick support
  280. Map of devices attached to JOY0DAT and JOY1DAT
  281. Format: <a>,<b>
  282. See also Documentation/kernel/input/joystick.txt
  283. analog.map= [HW,JOY] Analog joystick and gamepad support
  284. Specifies type or capabilities of an analog joystick
  285. connected to one of 16 gameports
  286. Format: <type1>,<type2>,..<type16>
  287. apc= [HW,SPARC]
  288. Power management functions (SPARCstation-4/5 + deriv.)
  289. Format: noidle
  290. Disable APC CPU standby support. SPARCstation-Fox does
  291. not play well with APC CPU idle - disable it if you have
  292. APC and your system crashes randomly.
  293. apic= [APIC,X86-32] Advanced Programmable Interrupt Controller
  294. Change the output verbosity whilst booting
  295. Format: { quiet (default) | verbose | debug }
  296. Change the amount of debugging information output
  297. when initialising the APIC and IO-APIC components.
  298. apm= [APM] Advanced Power Management
  299. See header of arch/x86/kernel/apm_32.c.
  300. arcrimi= [HW,NET] ARCnet - "RIM I" (entirely mem-mapped) cards
  301. Format: <io>,<irq>,<nodeID>
  302. ataflop= [HW,M68k]
  303. atarimouse= [HW,MOUSE] Atari Mouse
  304. atascsi= [HW,SCSI] Atari SCSI
  305. atkbd.extra= [HW] Enable extra LEDs and keys on IBM RapidAccess,
  306. EzKey and similar keyboards
  307. atkbd.reset= [HW] Reset keyboard during initialization
  308. atkbd.set= [HW] Select keyboard code set
  309. Format: <int> (2 = AT (default), 3 = PS/2)
  310. atkbd.scroll= [HW] Enable scroll wheel on MS Office and similar
  311. keyboards
  312. atkbd.softraw= [HW] Choose between synthetic and real raw mode
  313. Format: <bool> (0 = real, 1 = synthetic (default))
  314. atkbd.softrepeat= [HW]
  315. Use software keyboard repeat
  316. autotest [IA64]
  317. baycom_epp= [HW,AX25]
  318. Format: <io>,<mode>
  319. baycom_par= [HW,AX25] BayCom Parallel Port AX.25 Modem
  320. Format: <io>,<mode>
  321. See header of drivers/net/hamradio/baycom_par.c.
  322. baycom_ser_fdx= [HW,AX25]
  323. BayCom Serial Port AX.25 Modem (Full Duplex Mode)
  324. Format: <io>,<irq>,<mode>[,<baud>]
  325. See header of drivers/net/hamradio/baycom_ser_fdx.c.
  326. baycom_ser_hdx= [HW,AX25]
  327. BayCom Serial Port AX.25 Modem (Half Duplex Mode)
  328. Format: <io>,<irq>,<mode>
  329. See header of drivers/net/hamradio/baycom_ser_hdx.c.
  330. boot_delay= Milliseconds to delay each printk during boot.
  331. Values larger than 10 seconds (10000) are changed to
  332. no delay (0).
  333. Format: integer
  334. bootmem_debug [KNL] Enable bootmem allocator debug messages.
  335. bttv.card= [HW,V4L] bttv (bt848 + bt878 based grabber cards)
  336. bttv.radio= Most important insmod options are available as
  337. kernel args too.
  338. bttv.pll= See Documentation/video4linux/bttv/Insmod-options
  339. bttv.tuner= and Documentation/video4linux/bttv/CARDLIST
  340. BusLogic= [HW,SCSI]
  341. See drivers/scsi/BusLogic.c, comment before function
  342. BusLogic_ParseDriverOptions().
  343. c101= [NET] Moxa C101 synchronous serial card
  344. cachesize= [BUGS=X86-32] Override level 2 CPU cache size detection.
  345. Sometimes CPU hardware bugs make them report the cache
  346. size incorrectly. The kernel will attempt work arounds
  347. to fix known problems, but for some CPUs it is not
  348. possible to determine what the correct size should be.
  349. This option provides an override for these situations.
  350. capability.disable=
  351. [SECURITY] Disable capabilities. This would normally
  352. be used only if an alternative security model is to be
  353. configured. Potentially dangerous and should only be
  354. used if you are entirely sure of the consequences.
  355. ccw_timeout_log [S390]
  356. See Documentation/s390/CommonIO for details.
  357. cgroup_disable= [KNL] Disable a particular controller
  358. Format: {name of the controller(s) to disable}
  359. {Currently supported controllers - "memory"}
  360. checkreqprot [SELINUX] Set initial checkreqprot flag value.
  361. Format: { "0" | "1" }
  362. See security/selinux/Kconfig help text.
  363. 0 -- check protection applied by kernel (includes
  364. any implied execute protection).
  365. 1 -- check protection requested by application.
  366. Default value is set via a kernel config option.
  367. Value can be changed at runtime via
  368. /selinux/checkreqprot.
  369. cio_ignore= [S390]
  370. See Documentation/s390/CommonIO for details.
  371. clock= [BUGS=X86-32, HW] gettimeofday clocksource override.
  372. [Deprecated]
  373. Forces specified clocksource (if available) to be used
  374. when calculating gettimeofday(). If specified
  375. clocksource is not available, it defaults to PIT.
  376. Format: { pit | tsc | cyclone | pmtmr }
  377. clocksource= [GENERIC_TIME] Override the default clocksource
  378. Format: <string>
  379. Override the default clocksource and use the clocksource
  380. with the name specified.
  381. Some clocksource names to choose from, depending on
  382. the platform:
  383. [all] jiffies (this is the base, fallback clocksource)
  384. [ACPI] acpi_pm
  385. [ARM] imx_timer1,OSTS,netx_timer,mpu_timer2,
  386. pxa_timer,timer3,32k_counter,timer0_1
  387. [AVR32] avr32
  388. [X86-32] pit,hpet,tsc,vmi-timer;
  389. scx200_hrt on Geode; cyclone on IBM x440
  390. [MIPS] MIPS
  391. [PARISC] cr16
  392. [S390] tod
  393. [SH] SuperH
  394. [SPARC64] tick
  395. [X86-64] hpet,tsc
  396. clearcpuid=BITNUM [X86]
  397. Disable CPUID feature X for the kernel. See
  398. arch/x86/include/asm/cpufeature.h for the valid bit
  399. numbers. Note the Linux specific bits are not necessarily
  400. stable over kernel options, but the vendor specific
  401. ones should be.
  402. Also note that user programs calling CPUID directly
  403. or using the feature without checking anything
  404. will still see it. This just prevents it from
  405. being used by the kernel or shown in /proc/cpuinfo.
  406. Also note the kernel might malfunction if you disable
  407. some critical bits.
  408. cmo_free_hint= [PPC] Format: { yes | no }
  409. Specify whether pages are marked as being inactive
  410. when they are freed. This is used in CMO environments
  411. to determine OS memory pressure for page stealing by
  412. a hypervisor.
  413. Default: yes
  414. code_bytes [X86] How many bytes of object code to print
  415. in an oops report.
  416. Range: 0 - 8192
  417. Default: 64
  418. com20020= [HW,NET] ARCnet - COM20020 chipset
  419. Format:
  420. <io>[,<irq>[,<nodeID>[,<backplane>[,<ckp>[,<timeout>]]]]]
  421. com90io= [HW,NET] ARCnet - COM90xx chipset (IO-mapped buffers)
  422. Format: <io>[,<irq>]
  423. com90xx= [HW,NET]
  424. ARCnet - COM90xx chipset (memory-mapped buffers)
  425. Format: <io>[,<irq>[,<memstart>]]
  426. condev= [HW,S390] console device
  427. conmode=
  428. console= [KNL] Output console device and options.
  429. tty<n> Use the virtual console device <n>.
  430. ttyS<n>[,options]
  431. ttyUSB0[,options]
  432. Use the specified serial port. The options are of
  433. the form "bbbbpnf", where "bbbb" is the baud rate,
  434. "p" is parity ("n", "o", or "e"), "n" is number of
  435. bits, and "f" is flow control ("r" for RTS or
  436. omit it). Default is "9600n8".
  437. See Documentation/serial-console.txt for more
  438. information. See
  439. Documentation/networking/netconsole.txt for an
  440. alternative.
  441. uart[8250],io,<addr>[,options]
  442. uart[8250],mmio,<addr>[,options]
  443. Start an early, polled-mode console on the 8250/16550
  444. UART at the specified I/O port or MMIO address,
  445. switching to the matching ttyS device later. The
  446. options are the same as for ttyS, above.
  447. If the device connected to the port is not a TTY but a braille
  448. device, prepend "brl," before the device type, for instance
  449. console=brl,ttyS0
  450. For now, only VisioBraille is supported.
  451. consoleblank= [KNL] The console blank (screen saver) timeout in
  452. seconds. Defaults to 10*60 = 10mins. A value of 0
  453. disables the blank timer.
  454. coredump_filter=
  455. [KNL] Change the default value for
  456. /proc/<pid>/coredump_filter.
  457. See also Documentation/filesystems/proc.txt.
  458. cpcihp_generic= [HW,PCI] Generic port I/O CompactPCI driver
  459. Format:
  460. <first_slot>,<last_slot>,<port>,<enum_bit>[,<debug>]
  461. crashkernel=nn[KMG]@ss[KMG]
  462. [KNL] Reserve a chunk of physical memory to
  463. hold a kernel to switch to with kexec on panic.
  464. crashkernel=range1:size1[,range2:size2,...][@offset]
  465. [KNL] Same as above, but depends on the memory
  466. in the running system. The syntax of range is
  467. start-[end] where start and end are both
  468. a memory unit (amount[KMG]). See also
  469. Documentation/kdump/kdump.txt for a example.
  470. cs89x0_dma= [HW,NET]
  471. Format: <dma>
  472. cs89x0_media= [HW,NET]
  473. Format: { rj45 | aui | bnc }
  474. dasd= [HW,NET]
  475. See header of drivers/s390/block/dasd_devmap.c.
  476. db9.dev[2|3]= [HW,JOY] Multisystem joystick support via parallel port
  477. (one device per port)
  478. Format: <port#>,<type>
  479. See also Documentation/input/joystick-parport.txt
  480. debug [KNL] Enable kernel debugging (events log level).
  481. debug_locks_verbose=
  482. [KNL] verbose self-tests
  483. Format=<0|1>
  484. Print debugging info while doing the locking API
  485. self-tests.
  486. We default to 0 (no extra messages), setting it to
  487. 1 will print _a lot_ more information - normally
  488. only useful to kernel developers.
  489. debug_objects [KNL] Enable object debugging
  490. no_debug_objects
  491. [KNL] Disable object debugging
  492. debugpat [X86] Enable PAT debugging
  493. decnet.addr= [HW,NET]
  494. Format: <area>[,<node>]
  495. See also Documentation/networking/decnet.txt.
  496. default_hugepagesz=
  497. [same as hugepagesz=] The size of the default
  498. HugeTLB page size. This is the size represented by
  499. the legacy /proc/ hugepages APIs, used for SHM, and
  500. default size when mounting hugetlbfs filesystems.
  501. Defaults to the default architecture's huge page size
  502. if not specified.
  503. dhash_entries= [KNL]
  504. Set number of hash buckets for dentry cache.
  505. digi= [HW,SERIAL]
  506. IO parameters + enable/disable command.
  507. digiepca= [HW,SERIAL]
  508. See drivers/char/README.epca and
  509. Documentation/serial/digiepca.txt.
  510. disable_mtrr_cleanup [X86]
  511. The kernel tries to adjust MTRR layout from continuous
  512. to discrete, to make X server driver able to add WB
  513. entry later. This parameter disables that.
  514. disable_mtrr_trim [X86, Intel and AMD only]
  515. By default the kernel will trim any uncacheable
  516. memory out of your available memory pool based on
  517. MTRR settings. This parameter disables that behavior,
  518. possibly causing your machine to run very slowly.
  519. disable_timer_pin_1 [X86]
  520. Disable PIN 1 of APIC timer
  521. Can be useful to work around chipset bugs.
  522. dmasound= [HW,OSS] Sound subsystem buffers
  523. dma_debug=off If the kernel is compiled with DMA_API_DEBUG support,
  524. this option disables the debugging code at boot.
  525. dma_debug_entries=<number>
  526. This option allows to tune the number of preallocated
  527. entries for DMA-API debugging code. One entry is
  528. required per DMA-API allocation. Use this if the
  529. DMA-API debugging code disables itself because the
  530. architectural default is too low.
  531. dma_debug_driver=<driver_name>
  532. With this option the DMA-API debugging driver
  533. filter feature can be enabled at boot time. Just
  534. pass the driver to filter for as the parameter.
  535. The filter can be disabled or changed to another
  536. driver later using sysfs.
  537. dscc4.setup= [NET]
  538. dtc3181e= [HW,SCSI]
  539. dynamic_printk Enables pr_debug()/dev_dbg() calls if
  540. CONFIG_DYNAMIC_PRINTK_DEBUG has been enabled.
  541. These can also be switched on/off via
  542. <debugfs>/dynamic_printk/modules
  543. earlycon= [KNL] Output early console device and options.
  544. uart[8250],io,<addr>[,options]
  545. uart[8250],mmio,<addr>[,options]
  546. Start an early, polled-mode console on the 8250/16550
  547. UART at the specified I/O port or MMIO address.
  548. The options are the same as for ttyS, above.
  549. earlyprintk= [X86,SH,BLACKFIN]
  550. earlyprintk=vga
  551. earlyprintk=serial[,ttySn[,baudrate]]
  552. earlyprintk=dbgp
  553. Append ",keep" to not disable it when the real console
  554. takes over.
  555. Only vga or serial or usb debug port at a time.
  556. Currently only ttyS0 and ttyS1 are supported.
  557. Interaction with the standard serial driver is not
  558. very good.
  559. The VGA output is eventually overwritten by the real
  560. console.
  561. eata= [HW,SCSI]
  562. edd= [EDD]
  563. Format: {"off" | "on" | "skip[mbr]"}
  564. eisa_irq_edge= [PARISC,HW]
  565. See header of drivers/parisc/eisa.c.
  566. elanfreq= [X86-32]
  567. See comment before function elanfreq_setup() in
  568. arch/x86/kernel/cpu/cpufreq/elanfreq.c.
  569. elevator= [IOSCHED]
  570. Format: {"anticipatory" | "cfq" | "deadline" | "noop"}
  571. See Documentation/block/as-iosched.txt and
  572. Documentation/block/deadline-iosched.txt for details.
  573. elfcorehdr= [IA64,PPC,SH,X86]
  574. Specifies physical address of start of kernel core
  575. image elf header. Generally kexec loader will
  576. pass this option to capture kernel.
  577. See Documentation/kdump/kdump.txt for details.
  578. enable_mtrr_cleanup [X86]
  579. The kernel tries to adjust MTRR layout from continuous
  580. to discrete, to make X server driver able to add WB
  581. entry later. This parameter enables that.
  582. enable_timer_pin_1 [X86]
  583. Enable PIN 1 of APIC timer
  584. Can be useful to work around chipset bugs
  585. (in particular on some ATI chipsets).
  586. The kernel tries to set a reasonable default.
  587. enforcing [SELINUX] Set initial enforcing status.
  588. Format: {"0" | "1"}
  589. See security/selinux/Kconfig help text.
  590. 0 -- permissive (log only, no denials).
  591. 1 -- enforcing (deny and log).
  592. Default value is 0.
  593. Value can be changed at runtime via /selinux/enforce.
  594. ether= [HW,NET] Ethernet cards parameters
  595. This option is obsoleted by the "netdev=" option, which
  596. has equivalent usage. See its documentation for details.
  597. eurwdt= [HW,WDT] Eurotech CPU-1220/1410 onboard watchdog.
  598. Format: <io>[,<irq>]
  599. failslab=
  600. fail_page_alloc=
  601. fail_make_request=[KNL]
  602. General fault injection mechanism.
  603. Format: <interval>,<probability>,<space>,<times>
  604. See also /Documentation/fault-injection/.
  605. fd_mcs= [HW,SCSI]
  606. See header of drivers/scsi/fd_mcs.c.
  607. fdomain= [HW,SCSI]
  608. See header of drivers/scsi/fdomain.c.
  609. floppy= [HW]
  610. See Documentation/blockdev/floppy.txt.
  611. force_pal_cache_flush
  612. [IA-64] Avoid check_sal_cache_flush which may hang on
  613. buggy SAL_CACHE_FLUSH implementations. Using this
  614. parameter will force ia64_sal_cache_flush to call
  615. ia64_pal_cache_flush instead of SAL_CACHE_FLUSH.
  616. ftrace=[tracer]
  617. [FTRACE] will set and start the specified tracer
  618. as early as possible in order to facilitate early
  619. boot debugging.
  620. ftrace_dump_on_oops
  621. [FTRACE] will dump the trace buffers on oops.
  622. ftrace_filter=[function-list]
  623. [FTRACE] Limit the functions traced by the function
  624. tracer at boot up. function-list is a comma separated
  625. list of functions. This list can be changed at run
  626. time by the set_ftrace_filter file in the debugfs
  627. tracing directory.
  628. ftrace_notrace=[function-list]
  629. [FTRACE] Do not trace the functions specified in
  630. function-list. This list can be changed at run time
  631. by the set_ftrace_notrace file in the debugfs
  632. tracing directory.
  633. gamecon.map[2|3]=
  634. [HW,JOY] Multisystem joystick and NES/SNES/PSX pad
  635. support via parallel port (up to 5 devices per port)
  636. Format: <port#>,<pad1>,<pad2>,<pad3>,<pad4>,<pad5>
  637. See also Documentation/input/joystick-parport.txt
  638. gamma= [HW,DRM]
  639. gart_fix_e820= [X86_64] disable the fix e820 for K8 GART
  640. Format: off | on
  641. default: on
  642. gdth= [HW,SCSI]
  643. See header of drivers/scsi/gdth.c.
  644. gpt [EFI] Forces disk with valid GPT signature but
  645. invalid Protective MBR to be treated as GPT.
  646. gvp11= [HW,SCSI]
  647. hashdist= [KNL,NUMA] Large hashes allocated during boot
  648. are distributed across NUMA nodes. Defaults on
  649. for 64bit NUMA, off otherwise.
  650. Format: 0 | 1 (for off | on)
  651. hcl= [IA-64] SGI's Hardware Graph compatibility layer
  652. hd= [EIDE] (E)IDE hard drive subsystem geometry
  653. Format: <cyl>,<head>,<sect>
  654. highmem=nn[KMG] [KNL,BOOT] forces the highmem zone to have an exact
  655. size of <nn>. This works even on boxes that have no
  656. highmem otherwise. This also works to reduce highmem
  657. size on bigger boxes.
  658. highres= [KNL] Enable/disable high resolution timer mode.
  659. Valid parameters: "on", "off"
  660. Default: "on"
  661. hisax= [HW,ISDN]
  662. See Documentation/isdn/README.HiSax.
  663. hlt [BUGS=ARM,SH]
  664. hpet= [X86-32,HPET] option to control HPET usage
  665. Format: { enable (default) | disable | force |
  666. verbose }
  667. disable: disable HPET and use PIT instead
  668. force: allow force enabled of undocumented chips (ICH4,
  669. VIA, nVidia)
  670. verbose: show contents of HPET registers during setup
  671. hugepages= [HW,X86-32,IA-64] HugeTLB pages to allocate at boot.
  672. hugepagesz= [HW,IA-64,PPC,X86-64] The size of the HugeTLB pages.
  673. On x86-64 and powerpc, this option can be specified
  674. multiple times interleaved with hugepages= to reserve
  675. huge pages of different sizes. Valid pages sizes on
  676. x86-64 are 2M (when the CPU supports "pse") and 1G
  677. (when the CPU supports the "pdpe1gb" cpuinfo flag)
  678. Note that 1GB pages can only be allocated at boot time
  679. using hugepages= and not freed afterwards.
  680. hvc_iucv= [S390] Number of z/VM IUCV hypervisor console (HVC)
  681. terminal devices. Valid values: 0..8
  682. hvc_iucv_allow= [S390] Comma-separated list of z/VM user IDs.
  683. If specified, z/VM IUCV HVC accepts connections
  684. from listed z/VM user IDs only.
  685. i2c_bus= [HW] Override the default board specific I2C bus speed
  686. or register an additional I2C bus that is not
  687. registered from board initialization code.
  688. Format:
  689. <bus_id>,<clkrate>
  690. i8042.debug [HW] Toggle i8042 debug mode
  691. i8042.direct [HW] Put keyboard port into non-translated mode
  692. i8042.dumbkbd [HW] Pretend that controller can only read data from
  693. keyboard and cannot control its state
  694. (Don't attempt to blink the leds)
  695. i8042.noaux [HW] Don't check for auxiliary (== mouse) port
  696. i8042.nokbd [HW] Don't check/create keyboard port
  697. i8042.noloop [HW] Disable the AUX Loopback command while probing
  698. for the AUX port
  699. i8042.nomux [HW] Don't check presence of an active multiplexing
  700. controller
  701. i8042.nopnp [HW] Don't use ACPIPnP / PnPBIOS to discover KBD/AUX
  702. controllers
  703. i8042.panicblink=
  704. [HW] Frequency with which keyboard LEDs should blink
  705. when kernel panics (default is 0.5 sec)
  706. i8042.reset [HW] Reset the controller during init and cleanup
  707. i8042.unlock [HW] Unlock (ignore) the keylock
  708. i810= [HW,DRM]
  709. i8k.ignore_dmi [HW] Continue probing hardware even if DMI data
  710. indicates that the driver is running on unsupported
  711. hardware.
  712. i8k.force [HW] Activate i8k driver even if SMM BIOS signature
  713. does not match list of supported models.
  714. i8k.power_status
  715. [HW] Report power status in /proc/i8k
  716. (disabled by default)
  717. i8k.restricted [HW] Allow controlling fans only if SYS_ADMIN
  718. capability is set.
  719. ibmmcascsi= [HW,MCA,SCSI] IBM MicroChannel SCSI adapter
  720. See Documentation/mca.txt.
  721. icn= [HW,ISDN]
  722. Format: <io>[,<membase>[,<icn_id>[,<icn_id2>]]]
  723. ide-core.nodma= [HW] (E)IDE subsystem
  724. Format: =0.0 to prevent dma on hda, =0.1 hdb =1.0 hdc
  725. .vlb_clock .pci_clock .noflush .nohpa .noprobe .nowerr
  726. .cdrom .chs .ignore_cable are additional options
  727. See Documentation/ide/ide.txt.
  728. ide-pci-generic.all-generic-ide [HW] (E)IDE subsystem
  729. Claim all unknown PCI IDE storage controllers.
  730. idle= [X86]
  731. Format: idle=poll, idle=mwait, idle=halt, idle=nomwait
  732. Poll forces a polling idle loop that can slightly
  733. improve the performance of waking up a idle CPU, but
  734. will use a lot of power and make the system run hot.
  735. Not recommended.
  736. idle=mwait: On systems which support MONITOR/MWAIT but
  737. the kernel chose to not use it because it doesn't save
  738. as much power as a normal idle loop, use the
  739. MONITOR/MWAIT idle loop anyways. Performance should be
  740. the same as idle=poll.
  741. idle=halt: Halt is forced to be used for CPU idle.
  742. In such case C2/C3 won't be used again.
  743. idle=nomwait: Disable mwait for CPU C-states
  744. ignore_loglevel [KNL]
  745. Ignore loglevel setting - this will print /all/
  746. kernel messages to the console. Useful for debugging.
  747. ihash_entries= [KNL]
  748. Set number of hash buckets for inode cache.
  749. ima_audit= [IMA]
  750. Format: { "0" | "1" }
  751. 0 -- integrity auditing messages. (Default)
  752. 1 -- enable informational integrity auditing messages.
  753. ima_hash= [IMA]
  754. Formt: { "sha1" | "md5" }
  755. default: "sha1"
  756. ima_tcb [IMA]
  757. Load a policy which meets the needs of the Trusted
  758. Computing Base. This means IMA will measure all
  759. programs exec'd, files mmap'd for exec, and all files
  760. opened for read by uid=0.
  761. in2000= [HW,SCSI]
  762. See header of drivers/scsi/in2000.c.
  763. init= [KNL]
  764. Format: <full_path>
  765. Run specified binary instead of /sbin/init as init
  766. process.
  767. initcall_debug [KNL] Trace initcalls as they are executed. Useful
  768. for working out where the kernel is dying during
  769. startup.
  770. initrd= [BOOT] Specify the location of the initial ramdisk
  771. inport.irq= [HW] Inport (ATI XL and Microsoft) busmouse driver
  772. Format: <irq>
  773. intel_iommu= [DMAR] Intel IOMMU driver (DMAR) option
  774. on
  775. Enable intel iommu driver.
  776. off
  777. Disable intel iommu driver.
  778. igfx_off [Default Off]
  779. By default, gfx is mapped as normal device. If a gfx
  780. device has a dedicated DMAR unit, the DMAR unit is
  781. bypassed by not enabling DMAR with this option. In
  782. this case, gfx device will use physical address for
  783. DMA.
  784. forcedac [x86_64]
  785. With this option iommu will not optimize to look
  786. for io virtual address below 32 bit forcing dual
  787. address cycle on pci bus for cards supporting greater
  788. than 32 bit addressing. The default is to look
  789. for translation below 32 bit and if not available
  790. then look in the higher range.
  791. strict [Default Off]
  792. With this option on every unmap_single operation will
  793. result in a hardware IOTLB flush operation as opposed
  794. to batching them for performance.
  795. inttest= [IA64]
  796. iomem= Disable strict checking of access to MMIO memory
  797. strict regions from userspace.
  798. relaxed
  799. iommu= [x86]
  800. off
  801. force
  802. noforce
  803. biomerge
  804. panic
  805. nopanic
  806. merge
  807. nomerge
  808. forcesac
  809. soft
  810. io7= [HW] IO7 for Marvel based alpha systems
  811. See comment before marvel_specify_io7 in
  812. arch/alpha/kernel/core_marvel.c.
  813. io_delay= [X86] I/O delay method
  814. 0x80
  815. Standard port 0x80 based delay
  816. 0xed
  817. Alternate port 0xed based delay (needed on some systems)
  818. udelay
  819. Simple two microseconds delay
  820. none
  821. No delay
  822. ip= [IP_PNP]
  823. See Documentation/filesystems/nfsroot.txt.
  824. ip2= [HW] Set IO/IRQ pairs for up to 4 IntelliPort boards
  825. See comment before ip2_setup() in
  826. drivers/char/ip2/ip2base.c.
  827. ips= [HW,SCSI] Adaptec / IBM ServeRAID controller
  828. See header of drivers/scsi/ips.c.
  829. irqfixup [HW]
  830. When an interrupt is not handled search all handlers
  831. for it. Intended to get systems with badly broken
  832. firmware running.
  833. irqpoll [HW]
  834. When an interrupt is not handled search all handlers
  835. for it. Also check all handlers each timer
  836. interrupt. Intended to get systems with badly broken
  837. firmware running.
  838. isapnp= [ISAPNP]
  839. Format: <RDP>,<reset>,<pci_scan>,<verbosity>
  840. isolcpus= [KNL,SMP] Isolate CPUs from the general scheduler.
  841. Format:
  842. <cpu number>,...,<cpu number>
  843. or
  844. <cpu number>-<cpu number>
  845. (must be a positive range in ascending order)
  846. or a mixture
  847. <cpu number>,...,<cpu number>-<cpu number>
  848. This option can be used to specify one or more CPUs
  849. to isolate from the general SMP balancing and scheduling
  850. algorithms. You can move a process onto or off an
  851. "isolated" CPU via the CPU affinity syscalls or cpuset.
  852. <cpu number> begins at 0 and the maximum value is
  853. "number of CPUs in system - 1".
  854. This option is the preferred way to isolate CPUs. The
  855. alternative -- manually setting the CPU mask of all
  856. tasks in the system -- can cause problems and
  857. suboptimal load balancer performance.
  858. iucv= [HW,NET]
  859. js= [HW,JOY] Analog joystick
  860. See Documentation/input/joystick.txt.
  861. keepinitrd [HW,ARM]
  862. kernelcore=nn[KMG] [KNL,X86,IA-64,PPC] This parameter
  863. specifies the amount of memory usable by the kernel
  864. for non-movable allocations. The requested amount is
  865. spread evenly throughout all nodes in the system. The
  866. remaining memory in each node is used for Movable
  867. pages. In the event, a node is too small to have both
  868. kernelcore and Movable pages, kernelcore pages will
  869. take priority and other nodes will have a larger number
  870. of kernelcore pages. The Movable zone is used for the
  871. allocation of pages that may be reclaimed or moved
  872. by the page migration subsystem. This means that
  873. HugeTLB pages may not be allocated from this zone.
  874. Note that allocations like PTEs-from-HighMem still
  875. use the HighMem zone if it exists, and the Normal
  876. zone if it does not.
  877. kgdboc= [HW] kgdb over consoles.
  878. Requires a tty driver that supports console polling.
  879. (only serial supported for now)
  880. Format: <serial_device>[,baud]
  881. kmac= [MIPS] korina ethernet MAC address.
  882. Configure the RouterBoard 532 series on-chip
  883. Ethernet adapter MAC address.
  884. kmemleak= [KNL] Boot-time kmemleak enable/disable
  885. Valid arguments: on, off
  886. Default: on
  887. kstack=N [X86] Print N words from the kernel stack
  888. in oops dumps.
  889. l2cr= [PPC]
  890. l3cr= [PPC]
  891. lapic [X86-32,APIC] Enable the local APIC even if BIOS
  892. disabled it.
  893. lapic_timer_c2_ok [X86,APIC] trust the local apic timer
  894. in C2 power state.
  895. libata.dma= [LIBATA] DMA control
  896. libata.dma=0 Disable all PATA and SATA DMA
  897. libata.dma=1 PATA and SATA Disk DMA only
  898. libata.dma=2 ATAPI (CDROM) DMA only
  899. libata.dma=4 Compact Flash DMA only
  900. Combinations also work, so libata.dma=3 enables DMA
  901. for disks and CDROMs, but not CFs.
  902. libata.noacpi [LIBATA] Disables use of ACPI in libata suspend/resume
  903. when set.
  904. Format: <int>
  905. libata.force= [LIBATA] Force configurations. The format is comma
  906. separated list of "[ID:]VAL" where ID is
  907. PORT[:DEVICE]. PORT and DEVICE are decimal numbers
  908. matching port, link or device. Basically, it matches
  909. the ATA ID string printed on console by libata. If
  910. the whole ID part is omitted, the last PORT and DEVICE
  911. values are used. If ID hasn't been specified yet, the
  912. configuration applies to all ports, links and devices.
  913. If only DEVICE is omitted, the parameter applies to
  914. the port and all links and devices behind it. DEVICE
  915. number of 0 either selects the first device or the
  916. first fan-out link behind PMP device. It does not
  917. select the host link. DEVICE number of 15 selects the
  918. host link and device attached to it.
  919. The VAL specifies the configuration to force. As long
  920. as there's no ambiguity shortcut notation is allowed.
  921. For example, both 1.5 and 1.5G would work for 1.5Gbps.
  922. The following configurations can be forced.
  923. * Cable type: 40c, 80c, short40c, unk, ign or sata.
  924. Any ID with matching PORT is used.
  925. * SATA link speed limit: 1.5Gbps or 3.0Gbps.
  926. * Transfer mode: pio[0-7], mwdma[0-4] and udma[0-7].
  927. udma[/][16,25,33,44,66,100,133] notation is also
  928. allowed.
  929. * [no]ncq: Turn on or off NCQ.
  930. * nohrst, nosrst, norst: suppress hard, soft
  931. and both resets.
  932. If there are multiple matching configurations changing
  933. the same attribute, the last one is used.
  934. lmb=debug [KNL] Enable lmb debug messages.
  935. load_ramdisk= [RAM] List of ramdisks to load from floppy
  936. See Documentation/blockdev/ramdisk.txt.
  937. lockd.nlm_grace_period=P [NFS] Assign grace period.
  938. Format: <integer>
  939. lockd.nlm_tcpport=N [NFS] Assign TCP port.
  940. Format: <integer>
  941. lockd.nlm_timeout=T [NFS] Assign timeout value.
  942. Format: <integer>
  943. lockd.nlm_udpport=M [NFS] Assign UDP port.
  944. Format: <integer>
  945. logibm.irq= [HW,MOUSE] Logitech Bus Mouse Driver
  946. Format: <irq>
  947. loglevel= All Kernel Messages with a loglevel smaller than the
  948. console loglevel will be printed to the console. It can
  949. also be changed with klogd or other programs. The
  950. loglevels are defined as follows:
  951. 0 (KERN_EMERG) system is unusable
  952. 1 (KERN_ALERT) action must be taken immediately
  953. 2 (KERN_CRIT) critical conditions
  954. 3 (KERN_ERR) error conditions
  955. 4 (KERN_WARNING) warning conditions
  956. 5 (KERN_NOTICE) normal but significant condition
  957. 6 (KERN_INFO) informational
  958. 7 (KERN_DEBUG) debug-level messages
  959. log_buf_len=n Sets the size of the printk ring buffer, in bytes.
  960. Format: { n | nk | nM }
  961. n must be a power of two. The default size
  962. is set in the kernel config file.
  963. logo.nologo [FB] Disables display of the built-in Linux logo.
  964. This may be used to provide more screen space for
  965. kernel log messages and is useful when debugging
  966. kernel boot problems.
  967. lp=0 [LP] Specify parallel ports to use, e.g,
  968. lp=port[,port...] lp=none,parport0 (lp0 not configured, lp1 uses
  969. lp=reset first parallel port). 'lp=0' disables the
  970. lp=auto printer driver. 'lp=reset' (which can be
  971. specified in addition to the ports) causes
  972. attached printers to be reset. Using
  973. lp=port1,port2,... specifies the parallel ports
  974. to associate lp devices with, starting with
  975. lp0. A port specification may be 'none' to skip
  976. that lp device, or a parport name such as
  977. 'parport0'. Specifying 'lp=auto' instead of a
  978. port specification list means that device IDs
  979. from each port should be examined, to see if
  980. an IEEE 1284-compliant printer is attached; if
  981. so, the driver will manage that printer.
  982. See also header of drivers/char/lp.c.
  983. lpj=n [KNL]
  984. Sets loops_per_jiffy to given constant, thus avoiding
  985. time-consuming boot-time autodetection (up to 250 ms per
  986. CPU). 0 enables autodetection (default). To determine
  987. the correct value for your kernel, boot with normal
  988. autodetection and see what value is printed. Note that
  989. on SMP systems the preset will be applied to all CPUs,
  990. which is likely to cause problems if your CPUs need
  991. significantly divergent settings. An incorrect value
  992. will cause delays in the kernel to be wrong, leading to
  993. unpredictable I/O errors and other breakage. Although
  994. unlikely, in the extreme case this might damage your
  995. hardware.
  996. ltpc= [NET]
  997. Format: <io>,<irq>,<dma>
  998. mac5380= [HW,SCSI] Format:
  999. <can_queue>,<cmd_per_lun>,<sg_tablesize>,<hostid>,<use_tags>
  1000. machvec= [IA64] Force the use of a particular machine-vector
  1001. (machvec) in a generic kernel.
  1002. Example: machvec=hpzx1_swiotlb
  1003. max_addr=nn[KMG] [KNL,BOOT,ia64] All physical memory greater
  1004. than or equal to this physical address is ignored.
  1005. maxcpus= [SMP] Maximum number of processors that an SMP kernel
  1006. should make use of. maxcpus=n : n >= 0 limits the
  1007. kernel to using 'n' processors. n=0 is a special case,
  1008. it is equivalent to "nosmp", which also disables
  1009. the IO APIC.
  1010. max_loop= [LOOP] Maximum number of loopback devices that can
  1011. be mounted
  1012. Format: <1-256>
  1013. max_luns= [SCSI] Maximum number of LUNs to probe.
  1014. Should be between 1 and 2^32-1.
  1015. max_report_luns=
  1016. [SCSI] Maximum number of LUNs received.
  1017. Should be between 1 and 16384.
  1018. mcatest= [IA-64]
  1019. mce [X86-32] Machine Check Exception
  1020. mce=option [X86-64] See Documentation/x86/x86_64/boot-options.txt
  1021. md= [HW] RAID subsystems devices and level
  1022. See Documentation/md.txt.
  1023. mdacon= [MDA]
  1024. Format: <first>,<last>
  1025. Specifies range of consoles to be captured by the MDA.
  1026. mem=nn[KMG] [KNL,BOOT] Force usage of a specific amount of memory
  1027. Amount of memory to be used when the kernel is not able
  1028. to see the whole system memory or for test.
  1029. [X86-32] Use together with memmap= to avoid physical
  1030. address space collisions. Without memmap= PCI devices
  1031. could be placed at addresses belonging to unused RAM.
  1032. mem=nopentium [BUGS=X86-32] Disable usage of 4MB pages for kernel
  1033. memory.
  1034. memchunk=nn[KMG]
  1035. [KNL,SH] Allow user to override the default size for
  1036. per-device physically contiguous DMA buffers.
  1037. memmap=exactmap [KNL,X86] Enable setting of an exact
  1038. E820 memory map, as specified by the user.
  1039. Such memmap=exactmap lines can be constructed based on
  1040. BIOS output or other requirements. See the memmap=nn@ss
  1041. option description.
  1042. memmap=nn[KMG]@ss[KMG]
  1043. [KNL] Force usage of a specific region of memory
  1044. Region of memory to be used, from ss to ss+nn.
  1045. memmap=nn[KMG]#ss[KMG]
  1046. [KNL,ACPI] Mark specific memory as ACPI data.
  1047. Region of memory to be used, from ss to ss+nn.
  1048. memmap=nn[KMG]$ss[KMG]
  1049. [KNL,ACPI] Mark specific memory as reserved.
  1050. Region of memory to be used, from ss to ss+nn.
  1051. Example: Exclude memory from 0x18690000-0x1869ffff
  1052. memmap=64K$0x18690000
  1053. or
  1054. memmap=0x10000$0x18690000
  1055. memory_corruption_check=0/1 [X86]
  1056. Some BIOSes seem to corrupt the first 64k of
  1057. memory when doing things like suspend/resume.
  1058. Setting this option will scan the memory
  1059. looking for corruption. Enabling this will
  1060. both detect corruption and prevent the kernel
  1061. from using the memory being corrupted.
  1062. However, its intended as a diagnostic tool; if
  1063. repeatable BIOS-originated corruption always
  1064. affects the same memory, you can use memmap=
  1065. to prevent the kernel from using that memory.
  1066. memory_corruption_check_size=size [X86]
  1067. By default it checks for corruption in the low
  1068. 64k, making this memory unavailable for normal
  1069. use. Use this parameter to scan for
  1070. corruption in more or less memory.
  1071. memory_corruption_check_period=seconds [X86]
  1072. By default it checks for corruption every 60
  1073. seconds. Use this parameter to check at some
  1074. other rate. 0 disables periodic checking.
  1075. memtest= [KNL,X86] Enable memtest
  1076. Format: <integer>
  1077. default : 0 <disable>
  1078. Specifies the number of memtest passes to be
  1079. performed. Each pass selects another test
  1080. pattern from a given set of patterns. Memtest
  1081. fills the memory with this pattern, validates
  1082. memory contents and reserves bad memory
  1083. regions that are detected.
  1084. meye.*= [HW] Set MotionEye Camera parameters
  1085. See Documentation/video4linux/meye.txt.
  1086. mfgpt_irq= [IA-32] Specify the IRQ to use for the
  1087. Multi-Function General Purpose Timers on AMD Geode
  1088. platforms.
  1089. mfgptfix [X86-32] Fix MFGPT timers on AMD Geode platforms when
  1090. the BIOS has incorrectly applied a workaround. TinyBIOS
  1091. version 0.98 is known to be affected, 0.99 fixes the
  1092. problem by letting the user disable the workaround.
  1093. mga= [HW,DRM]
  1094. min_addr=nn[KMG] [KNL,BOOT,ia64] All physical memory below this
  1095. physical address is ignored.
  1096. mminit_loglevel=
  1097. [KNL] When CONFIG_DEBUG_MEMORY_INIT is set, this
  1098. parameter allows control of the logging verbosity for
  1099. the additional memory initialisation checks. A value
  1100. of 0 disables mminit logging and a level of 4 will
  1101. log everything. Information is printed at KERN_DEBUG
  1102. so loglevel=8 may also need to be specified.
  1103. mousedev.tap_time=
  1104. [MOUSE] Maximum time between finger touching and
  1105. leaving touchpad surface for touch to be considered
  1106. a tap and be reported as a left button click (for
  1107. touchpads working in absolute mode only).
  1108. Format: <msecs>
  1109. mousedev.xres= [MOUSE] Horizontal screen resolution, used for devices
  1110. reporting absolute coordinates, such as tablets
  1111. mousedev.yres= [MOUSE] Vertical screen resolution, used for devices
  1112. reporting absolute coordinates, such as tablets
  1113. movablecore=nn[KMG] [KNL,X86,IA-64,PPC] This parameter
  1114. is similar to kernelcore except it specifies the
  1115. amount of memory used for migratable allocations.
  1116. If both kernelcore and movablecore is specified,
  1117. then kernelcore will be at *least* the specified
  1118. value but may be more. If movablecore on its own
  1119. is specified, the administrator must be careful
  1120. that the amount of memory usable for all allocations
  1121. is not too small.
  1122. mpu401= [HW,OSS]
  1123. Format: <io>,<irq>
  1124. MTD_Partition= [MTD]
  1125. Format: <name>,<region-number>,<size>,<offset>
  1126. MTD_Region= [MTD] Format:
  1127. <name>,<region-number>[,<base>,<size>,<buswidth>,<altbuswidth>]
  1128. mtdparts= [MTD]
  1129. See drivers/mtd/cmdlinepart.c.
  1130. mtdset= [ARM]
  1131. ARM/S3C2412 JIVE boot control
  1132. See arch/arm/mach-s3c2412/mach-jive.c
  1133. mtouchusb.raw_coordinates=
  1134. [HW] Make the MicroTouch USB driver use raw coordinates
  1135. ('y', default) or cooked coordinates ('n')
  1136. mtrr_chunk_size=nn[KMG] [X86]
  1137. used for mtrr cleanup. It is largest continuous chunk
  1138. that could hold holes aka. UC entries.
  1139. mtrr_gran_size=nn[KMG] [X86]
  1140. Used for mtrr cleanup. It is granularity of mtrr block.
  1141. Default is 1.
  1142. Large value could prevent small alignment from
  1143. using up MTRRs.
  1144. mtrr_spare_reg_nr=n [X86]
  1145. Format: <integer>
  1146. Range: 0,7 : spare reg number
  1147. Default : 1
  1148. Used for mtrr cleanup. It is spare mtrr entries number.
  1149. Set to 2 or more if your graphical card needs more.
  1150. n2= [NET] SDL Inc. RISCom/N2 synchronous serial card
  1151. NCR_D700= [HW,SCSI]
  1152. See header of drivers/scsi/NCR_D700.c.
  1153. ncr5380= [HW,SCSI]
  1154. ncr53c400= [HW,SCSI]
  1155. ncr53c400a= [HW,SCSI]
  1156. ncr53c406a= [HW,SCSI]
  1157. ncr53c8xx= [HW,SCSI]
  1158. netdev= [NET] Network devices parameters
  1159. Format: <irq>,<io>,<mem_start>,<mem_end>,<name>
  1160. Note that mem_start is often overloaded to mean
  1161. something different and driver-specific.
  1162. This usage is only documented in each driver source
  1163. file if at all.
  1164. nf_conntrack.acct=
  1165. [NETFILTER] Enable connection tracking flow accounting
  1166. 0 to disable accounting
  1167. 1 to enable accounting
  1168. Default value depends on CONFIG_NF_CT_ACCT that is
  1169. going to be removed in 2.6.29.
  1170. nfsaddrs= [NFS]
  1171. See Documentation/filesystems/nfsroot.txt.
  1172. nfsroot= [NFS] nfs root filesystem for disk-less boxes.
  1173. See Documentation/filesystems/nfsroot.txt.
  1174. nfs.callback_tcpport=
  1175. [NFS] set the TCP port on which the NFSv4 callback
  1176. channel should listen.
  1177. nfs.idmap_cache_timeout=
  1178. [NFS] set the maximum lifetime for idmapper cache
  1179. entries.
  1180. nfs.enable_ino64=
  1181. [NFS] enable 64-bit inode numbers.
  1182. If zero, the NFS client will fake up a 32-bit inode
  1183. number for the readdir() and stat() syscalls instead
  1184. of returning the full 64-bit number.
  1185. The default is to return 64-bit inode numbers.
  1186. nmi_debug= [KNL,AVR32] Specify one or more actions to take
  1187. when a NMI is triggered.
  1188. Format: [state][,regs][,debounce][,die]
  1189. nmi_watchdog= [KNL,BUGS=X86] Debugging features for SMP kernels
  1190. Format: [panic,][num]
  1191. Valid num: 0,1,2
  1192. 0 - turn nmi_watchdog off
  1193. 1 - use the IO-APIC timer for the NMI watchdog
  1194. 2 - use the local APIC for the NMI watchdog using
  1195. a performance counter. Note: This will use one
  1196. performance counter and the local APIC's performance
  1197. vector.
  1198. When panic is specified, panic when an NMI watchdog
  1199. timeout occurs.
  1200. This is useful when you use a panic=... timeout and
  1201. need the box quickly up again.
  1202. Instead of 1 and 2 it is possible to use the following
  1203. symbolic names: lapic and ioapic
  1204. Example: nmi_watchdog=2 or nmi_watchdog=panic,lapic
  1205. no387 [BUGS=X86-32] Tells the kernel to use the 387 maths
  1206. emulation library even if a 387 maths coprocessor
  1207. is present.
  1208. no_console_suspend
  1209. [HW] Never suspend the console
  1210. Disable suspending of consoles during suspend and
  1211. hibernate operations. Once disabled, debugging
  1212. messages can reach various consoles while the rest
  1213. of the system is being put to sleep (ie, while
  1214. debugging driver suspend/resume hooks). This may
  1215. not work reliably with all consoles, but is known
  1216. to work with serial and VGA consoles.
  1217. noaliencache [MM, NUMA, SLAB] Disables the allocation of alien
  1218. caches in the slab allocator. Saves per-node memory,
  1219. but will impact performance.
  1220. noalign [KNL,ARM]
  1221. noapic [SMP,APIC] Tells the kernel to not make use of any
  1222. IOAPICs that may be present in the system.
  1223. nobats [PPC] Do not use BATs for mapping kernel lowmem
  1224. on "Classic" PPC cores.
  1225. nocache [ARM]
  1226. noclflush [BUGS=X86] Don't use the CLFLUSH instruction
  1227. nodelayacct [KNL] Disable per-task delay accounting
  1228. nodisconnect [HW,SCSI,M68K] Disables SCSI disconnects.
  1229. nodsp [SH] Disable hardware DSP at boot time.
  1230. noefi [X86] Disable EFI runtime services support.
  1231. noexec [IA-64]
  1232. noexec [X86]
  1233. On X86-32 available only on PAE configured kernels.
  1234. noexec=on: enable non-executable mappings (default)
  1235. noexec=off: disable non-executable mappings
  1236. noexec32 [X86-64]
  1237. This affects only 32-bit executables.
  1238. noexec32=on: enable non-executable mappings (default)
  1239. read doesn't imply executable mappings
  1240. noexec32=off: disable non-executable mappings
  1241. read implies executable mappings
  1242. nofpu [SH] Disable hardware FPU at boot time.
  1243. nofxsr [BUGS=X86-32] Disables x86 floating point extended
  1244. register save and restore. The kernel will only save
  1245. legacy floating-point registers on task switch.
  1246. noxsave [BUGS=X86] Disables x86 extended register state save
  1247. and restore using xsave. The kernel will fallback to
  1248. enabling legacy floating-point and sse state.
  1249. nohlt [BUGS=ARM,SH] Tells the kernel that the sleep(SH) or
  1250. wfi(ARM) instruction doesn't work correctly and not to
  1251. use it. This is also useful when using JTAG debugger.
  1252. no-hlt [BUGS=X86-32] Tells the kernel that the hlt
  1253. instruction doesn't work correctly and not to
  1254. use it.
  1255. no_file_caps Tells the kernel not to honor file capabilities. The
  1256. only way then for a file to be executed with privilege
  1257. is to be setuid root or executed by root.
  1258. nohalt [IA-64] Tells the kernel not to use the power saving
  1259. function PAL_HALT_LIGHT when idle. This increases
  1260. power-consumption. On the positive side, it reduces
  1261. interrupt wake-up latency, which may improve performance
  1262. in certain environments such as networked servers or
  1263. real-time systems.
  1264. nohz= [KNL] Boottime enable/disable dynamic ticks
  1265. Valid arguments: on, off
  1266. Default: on
  1267. noiotrap [SH] Disables trapped I/O port accesses.
  1268. noirqdebug [X86-32] Disables the code which attempts to detect and
  1269. disable unhandled interrupt sources.
  1270. no_timer_check [X86,APIC] Disables the code which tests for
  1271. broken timer IRQ sources.
  1272. noisapnp [ISAPNP] Disables ISA PnP code.
  1273. noinitrd [RAM] Tells the kernel not to load any configured
  1274. initial RAM disk.
  1275. nointremap [X86-64, Intel-IOMMU] Do not enable interrupt
  1276. remapping.
  1277. nointroute [IA-64]
  1278. nojitter [IA64] Disables jitter checking for ITC timers.
  1279. nolapic [X86-32,APIC] Do not enable or use the local APIC.
  1280. nolapic_timer [X86-32,APIC] Do not use the local APIC timer.
  1281. noltlbs [PPC] Do not use large page/tlb entries for kernel
  1282. lowmem mapping on PPC40x.
  1283. nomca [IA-64] Disable machine check abort handling
  1284. nomce [X86-32] Machine Check Exception
  1285. nomfgpt [X86-32] Disable Multi-Function General Purpose
  1286. Timer usage (for AMD Geode machines).
  1287. norandmaps Don't use address space randomization. Equivalent to
  1288. echo 0 > /proc/sys/kernel/randomize_va_space
  1289. noreplace-paravirt [X86-32,PV_OPS] Don't patch paravirt_ops
  1290. noreplace-smp [X86-32,SMP] Don't replace SMP instructions
  1291. with UP alternatives
  1292. noresidual [PPC] Don't use residual data on PReP machines.
  1293. noresume [SWSUSP] Disables resume and restores original swap
  1294. space.
  1295. no-scroll [VGA] Disables scrollback.
  1296. This is required for the Braillex ib80-piezo Braille
  1297. reader made by F.H. Papenmeier (Germany).
  1298. nosbagart [IA-64]
  1299. nosep [BUGS=X86-32] Disables x86 SYSENTER/SYSEXIT support.
  1300. nosmp [SMP] Tells an SMP kernel to act as a UP kernel,
  1301. and disable the IO APIC. legacy for "maxcpus=0".
  1302. nosoftlockup [KNL] Disable the soft-lockup detector.
  1303. noswapaccount [KNL] Disable accounting of swap in memory resource
  1304. controller. (See Documentation/cgroups/memory.txt)
  1305. nosync [HW,M68K] Disables sync negotiation for all devices.
  1306. notsc [BUGS=X86-32] Disable Time Stamp Counter
  1307. nousb [USB] Disable the USB subsystem
  1308. nowb [ARM]
  1309. nox2apic [X86-64,APIC] Do not enable x2APIC mode.
  1310. nptcg= [IA64] Override max number of concurrent global TLB
  1311. purges which is reported from either PAL_VM_SUMMARY or
  1312. SAL PALO.
  1313. nr_uarts= [SERIAL] maximum number of UARTs to be registered.
  1314. numa_zonelist_order= [KNL, BOOT] Select zonelist order for NUMA.
  1315. one of ['zone', 'node', 'default'] can be specified
  1316. This can be set from sysctl after boot.
  1317. See Documentation/sysctl/vm.txt for details.
  1318. ohci1394_dma=early [HW] enable debugging via the ohci1394 driver.
  1319. See Documentation/debugging-via-ohci1394.txt for more
  1320. info.
  1321. olpc_ec_timeout= [OLPC] ms delay when issuing EC commands
  1322. Rather than timing out after 20 ms if an EC
  1323. command is not properly ACKed, override the length
  1324. of the timeout. We have interrupts disabled while
  1325. waiting for the ACK, so if this is set too high
  1326. interrupts *may* be lost!
  1327. opl3= [HW,OSS]
  1328. Format: <io>
  1329. oprofile.timer= [HW]
  1330. Use timer interrupt instead of performance counters
  1331. oprofile.cpu_type= Force an oprofile cpu type
  1332. This might be useful if you have an older oprofile
  1333. userland or if you want common events.
  1334. Format: { archperfmon }
  1335. archperfmon: [X86] Force use of architectural
  1336. perfmon on Intel CPUs instead of the
  1337. CPU specific event set.
  1338. osst= [HW,SCSI] SCSI Tape Driver
  1339. Format: <buffer_size>,<write_threshold>
  1340. See also Documentation/scsi/st.txt.
  1341. panic= [KNL] Kernel behaviour on panic
  1342. Format: <timeout>
  1343. parkbd.port= [HW] Parallel port number the keyboard adapter is
  1344. connected to, default is 0.
  1345. Format: <parport#>
  1346. parkbd.mode= [HW] Parallel port keyboard adapter mode of operation,
  1347. 0 for XT, 1 for AT (default is AT).
  1348. Format: <mode>
  1349. parport= [HW,PPT] Specify parallel ports. 0 disables.
  1350. Format: { 0 | auto | 0xBBB[,IRQ[,DMA]] }
  1351. Use 'auto' to force the driver to use any
  1352. IRQ/DMA settings detected (the default is to
  1353. ignore detected IRQ/DMA settings because of
  1354. possible conflicts). You can specify the base
  1355. address, IRQ, and DMA settings; IRQ and DMA
  1356. should be numbers, or 'auto' (for using detected
  1357. settings on that particular port), or 'nofifo'
  1358. (to avoid using a FIFO even if it is detected).
  1359. Parallel ports are assigned in the order they
  1360. are specified on the command line, starting
  1361. with parport0.
  1362. parport_init_mode= [HW,PPT]
  1363. Configure VIA parallel port to operate in
  1364. a specific mode. This is necessary on Pegasos
  1365. computer where firmware has no options for setting
  1366. up parallel port mode and sets it to spp.
  1367. Currently this function knows 686a and 8231 chips.
  1368. Format: [spp|ps2|epp|ecp|ecpepp]
  1369. pas2= [HW,OSS] Format:
  1370. <io>,<irq>,<dma>,<dma16>,<sb_io>,<sb_irq>,<sb_dma>,<sb_dma16>
  1371. pas16= [HW,SCSI]
  1372. See header of drivers/scsi/pas16.c.
  1373. pause_on_oops=
  1374. Halt all CPUs after the first oops has been printed for
  1375. the specified number of seconds. This is to be used if
  1376. your oopses keep scrolling off the screen.
  1377. pcbit= [HW,ISDN]
  1378. pcd. [PARIDE]
  1379. See header of drivers/block/paride/pcd.c.
  1380. See also Documentation/blockdev/paride.txt.
  1381. pci=option[,option...] [PCI] various PCI subsystem options:
  1382. earlydump [X86] dump PCI config space before the kernel
  1383. changes anything
  1384. off [X86] don't probe for the PCI bus
  1385. bios [X86-32] force use of PCI BIOS, don't access
  1386. the hardware directly. Use this if your machine
  1387. has a non-standard PCI host bridge.
  1388. nobios [X86-32] disallow use of PCI BIOS, only direct
  1389. hardware access methods are allowed. Use this
  1390. if you experience crashes upon bootup and you
  1391. suspect they are caused by the BIOS.
  1392. conf1 [X86] Force use of PCI Configuration
  1393. Mechanism 1.
  1394. conf2 [X86] Force use of PCI Configuration
  1395. Mechanism 2.
  1396. noaer [PCIE] If the PCIEAER kernel config parameter is
  1397. enabled, this kernel boot option can be used to
  1398. disable the use of PCIE advanced error reporting.
  1399. nodomains [PCI] Disable support for multiple PCI
  1400. root domains (aka PCI segments, in ACPI-speak).
  1401. nommconf [X86] Disable use of MMCONFIG for PCI
  1402. Configuration
  1403. nomsi [MSI] If the PCI_MSI kernel config parameter is
  1404. enabled, this kernel boot option can be used to
  1405. disable the use of MSI interrupts system-wide.
  1406. noioapicquirk [APIC] Disable all boot interrupt quirks.
  1407. Safety option to keep boot IRQs enabled. This
  1408. should never be necessary.
  1409. ioapicreroute [APIC] Enable rerouting of boot IRQs to the
  1410. primary IO-APIC for bridges that cannot disable
  1411. boot IRQs. This fixes a source of spurious IRQs
  1412. when the system masks IRQs.
  1413. noioapicreroute [APIC] Disable workaround that uses the
  1414. boot IRQ equivalent of an IRQ that connects to
  1415. a chipset where boot IRQs cannot be disabled.
  1416. The opposite of ioapicreroute.
  1417. biosirq [X86-32] Use PCI BIOS calls to get the interrupt
  1418. routing table. These calls are known to be buggy
  1419. on several machines and they hang the machine
  1420. when used, but on other computers it's the only
  1421. way to get the interrupt routing table. Try
  1422. this option if the kernel is unable to allocate
  1423. IRQs or discover secondary PCI buses on your
  1424. motherboard.
  1425. rom [X86] Assign address space to expansion ROMs.
  1426. Use with caution as certain devices share
  1427. address decoders between ROMs and other
  1428. resources.
  1429. norom [X86] Do not assign address space to
  1430. expansion ROMs that do not already have
  1431. BIOS assigned address ranges.
  1432. irqmask=0xMMMM [X86] Set a bit mask of IRQs allowed to be
  1433. assigned automatically to PCI devices. You can
  1434. make the kernel exclude IRQs of your ISA cards
  1435. this way.
  1436. pirqaddr=0xAAAAA [X86] Specify the physical address
  1437. of the PIRQ table (normally generated
  1438. by the BIOS) if it is outside the
  1439. F0000h-100000h range.
  1440. lastbus=N [X86] Scan all buses thru bus #N. Can be
  1441. useful if the kernel is unable to find your
  1442. secondary buses and you want to tell it
  1443. explicitly which ones they are.
  1444. assign-busses [X86] Always assign all PCI bus
  1445. numbers ourselves, overriding
  1446. whatever the firmware may have done.
  1447. usepirqmask [X86] Honor the possible IRQ mask stored
  1448. in the BIOS $PIR table. This is needed on
  1449. some systems with broken BIOSes, notably
  1450. some HP Pavilion N5400 and Omnibook XE3
  1451. notebooks. This will have no effect if ACPI
  1452. IRQ routing is enabled.
  1453. noacpi [X86] Do not use ACPI for IRQ routing
  1454. or for PCI scanning.
  1455. use_crs [X86] Use _CRS for PCI resource
  1456. allocation.
  1457. routeirq Do IRQ routing for all PCI devices.
  1458. This is normally done in pci_enable_device(),
  1459. so this option is a temporary workaround
  1460. for broken drivers that don't call it.
  1461. skip_isa_align [X86] do not align io start addr, so can
  1462. handle more pci cards
  1463. firmware [ARM] Do not re-enumerate the bus but instead
  1464. just use the configuration from the
  1465. bootloader. This is currently used on
  1466. IXP2000 systems where the bus has to be
  1467. configured a certain way for adjunct CPUs.
  1468. noearly [X86] Don't do any early type 1 scanning.
  1469. This might help on some broken boards which
  1470. machine check when some devices' config space
  1471. is read. But various workarounds are disabled
  1472. and some IOMMU drivers will not work.
  1473. bfsort Sort PCI devices into breadth-first order.
  1474. This sorting is done to get a device
  1475. order compatible with older (<= 2.4) kernels.
  1476. nobfsort Don't sort PCI devices into breadth-first order.
  1477. cbiosize=nn[KMG] The fixed amount of bus space which is
  1478. reserved for the CardBus bridge's IO window.
  1479. The default value is 256 bytes.
  1480. cbmemsize=nn[KMG] The fixed amount of bus space which is
  1481. reserved for the CardBus bridge's memory
  1482. window. The default value is 64 megabytes.
  1483. resource_alignment=
  1484. Format:
  1485. [<order of align>@][<domain>:]<bus>:<slot>.<func>[; ...]
  1486. Specifies alignment and device to reassign
  1487. aligned memory resources.
  1488. If <order of align> is not specified,
  1489. PAGE_SIZE is used as alignment.
  1490. PCI-PCI bridge can be specified, if resource
  1491. windows need to be expanded.
  1492. pcie_aspm= [PCIE] Forcibly enable or disable PCIe Active State Power
  1493. Management.
  1494. off Disable ASPM.
  1495. force Enable ASPM even on devices that claim not to support it.
  1496. WARNING: Forcing ASPM on may cause system lockups.
  1497. pcmv= [HW,PCMCIA] BadgePAD 4
  1498. pd. [PARIDE]
  1499. See Documentation/blockdev/paride.txt.
  1500. pdcchassis= [PARISC,HW] Disable/Enable PDC Chassis Status codes at
  1501. boot time.
  1502. Format: { 0 | 1 }
  1503. See arch/parisc/kernel/pdc_chassis.c
  1504. pf. [PARIDE]
  1505. See Documentation/blockdev/paride.txt.
  1506. pg. [PARIDE]
  1507. See Documentation/blockdev/paride.txt.
  1508. pirq= [SMP,APIC] Manual mp-table setup
  1509. See Documentation/x86/i386/IO-APIC.txt.
  1510. plip= [PPT,NET] Parallel port network link
  1511. Format: { parport<nr> | timid | 0 }
  1512. See also Documentation/parport.txt.
  1513. pmtmr= [X86] Manual setup of pmtmr I/O Port.
  1514. Override pmtimer IOPort with a hex value.
  1515. e.g. pmtmr=0x508
  1516. pnp.debug [PNP]
  1517. Enable PNP debug messages. This depends on the
  1518. CONFIG_PNP_DEBUG_MESSAGES option.
  1519. pnpacpi= [ACPI]
  1520. { off }
  1521. pnpbios= [ISAPNP]
  1522. { on | off | curr | res | no-curr | no-res }
  1523. pnp_reserve_irq=
  1524. [ISAPNP] Exclude IRQs for the autoconfiguration
  1525. pnp_reserve_dma=
  1526. [ISAPNP] Exclude DMAs for the autoconfiguration
  1527. pnp_reserve_io= [ISAPNP] Exclude I/O ports for the autoconfiguration
  1528. Ranges are in pairs (I/O port base and size).
  1529. pnp_reserve_mem=
  1530. [ISAPNP] Exclude memory regions for the
  1531. autoconfiguration.
  1532. Ranges are in pairs (memory base and size).
  1533. ports= [IP_VS_FTP] IPVS ftp helper module
  1534. Default is 21.
  1535. Up to 8 (IP_VS_APP_MAX_PORTS) ports
  1536. may be specified.
  1537. Format: <port>,<port>....
  1538. print-fatal-signals=
  1539. [KNL] debug: print fatal signals
  1540. print-fatal-signals=1: print segfault info to
  1541. the kernel console.
  1542. default: off.
  1543. printk.time= Show timing data prefixed to each printk message line
  1544. Format: <bool> (1/Y/y=enable, 0/N/n=disable)
  1545. processor.max_cstate= [HW,ACPI]
  1546. Limit processor to maximum C-state
  1547. max_cstate=9 overrides any DMI blacklist limit.
  1548. processor.nocst [HW,ACPI]
  1549. Ignore the _CST method to determine C-states,
  1550. instead using the legacy FADT method
  1551. profile= [KNL] Enable kernel profiling via /proc/profile
  1552. Format: [schedule,]<number>
  1553. Param: "schedule" - profile schedule points.
  1554. Param: <number> - step/bucket size as a power of 2 for
  1555. statistical time based profiling.
  1556. Param: "sleep" - profile D-state sleeping (millisecs).
  1557. Requires CONFIG_SCHEDSTATS
  1558. Param: "kvm" - profile VM exits.
  1559. prompt_ramdisk= [RAM] List of RAM disks to prompt for floppy disk
  1560. before loading.
  1561. See Documentation/blockdev/ramdisk.txt.
  1562. psmouse.proto= [HW,MOUSE] Highest PS2 mouse protocol extension to
  1563. probe for; one of (bare|imps|exps|lifebook|any).
  1564. psmouse.rate= [HW,MOUSE] Set desired mouse report rate, in reports
  1565. per second.
  1566. psmouse.resetafter= [HW,MOUSE]
  1567. Try to reset the device after so many bad packets
  1568. (0 = never).
  1569. psmouse.resolution=
  1570. [HW,MOUSE] Set desired mouse resolution, in dpi.
  1571. psmouse.smartscroll=
  1572. [HW,MOUSE] Controls Logitech smartscroll autorepeat.
  1573. 0 = disabled, 1 = enabled (default).
  1574. pss= [HW,OSS] Personal Sound System (ECHO ESC614)
  1575. Format:
  1576. <io>,<mss_io>,<mss_irq>,<mss_dma>,<mpu_io>,<mpu_irq>
  1577. pt. [PARIDE]
  1578. See Documentation/blockdev/paride.txt.
  1579. pty.legacy_count=
  1580. [KNL] Number of legacy pty's. Overwrites compiled-in
  1581. default number.
  1582. quiet [KNL] Disable most log messages
  1583. r128= [HW,DRM]
  1584. raid= [HW,RAID]
  1585. See Documentation/md.txt.
  1586. ramdisk_blocksize= [RAM]
  1587. See Documentation/blockdev/ramdisk.txt.
  1588. ramdisk_size= [RAM] Sizes of RAM disks in kilobytes
  1589. See Documentation/blockdev/ramdisk.txt.
  1590. rcupdate.blimit= [KNL,BOOT]
  1591. Set maximum number of finished RCU callbacks to process
  1592. in one batch.
  1593. rcupdate.qhimark= [KNL,BOOT]
  1594. Set threshold of queued
  1595. RCU callbacks over which batch limiting is disabled.
  1596. rcupdate.qlowmark= [KNL,BOOT]
  1597. Set threshold of queued RCU callbacks below which
  1598. batch limiting is re-enabled.
  1599. rdinit= [KNL]
  1600. Format: <full_path>
  1601. Run specified binary instead of /init from the ramdisk,
  1602. used for early userspace startup. See initrd.
  1603. reboot= [BUGS=X86-32,BUGS=ARM,BUGS=IA-64] Rebooting mode
  1604. Format: <reboot_mode>[,<reboot_mode2>[,...]]
  1605. See arch/*/kernel/reboot.c or arch/*/kernel/process.c
  1606. relax_domain_level=
  1607. [KNL, SMP] Set scheduler's default relax_domain_level.
  1608. See Documentation/cgroups/cpusets.txt.
  1609. reserve= [KNL,BUGS] Force the kernel to ignore some iomem area
  1610. reservetop= [X86-32]
  1611. Format: nn[KMG]
  1612. Reserves a hole at the top of the kernel virtual
  1613. address space.
  1614. reset_devices [KNL] Force drivers to reset the underlying device
  1615. during initialization.
  1616. resume= [SWSUSP]
  1617. Specify the partition device for software suspend
  1618. resume_offset= [SWSUSP]
  1619. Specify the offset from the beginning of the partition
  1620. given by "resume=" at which the swap header is located,
  1621. in <PAGE_SIZE> units (needed only for swap files).
  1622. See Documentation/power/swsusp-and-swap-files.txt
  1623. retain_initrd [RAM] Keep initrd memory after extraction
  1624. rhash_entries= [KNL,NET]
  1625. Set number of hash buckets for route cache
  1626. riscom8= [HW,SERIAL]
  1627. Format: <io_board1>[,<io_board2>[,...<io_boardN>]]
  1628. ro [KNL] Mount root device read-only on boot
  1629. root= [KNL] Root filesystem
  1630. rootdelay= [KNL] Delay (in seconds) to pause before attempting to
  1631. mount the root filesystem
  1632. rootflags= [KNL] Set root filesystem mount option string
  1633. rootfstype= [KNL] Set root filesystem type
  1634. rootwait [KNL] Wait (indefinitely) for root device to show up.
  1635. Useful for devices that are detected asynchronously
  1636. (e.g. USB and MMC devices).
  1637. root_plug.vendor_id=
  1638. [ROOTPLUG] Override the default vendor ID
  1639. root_plug.product_id=
  1640. [ROOTPLUG] Override the default product ID
  1641. root_plug.debug=
  1642. [ROOTPLUG] Enable debugging output
  1643. rw [KNL] Mount root device read-write on boot
  1644. S [KNL] Run init in single mode
  1645. sa1100ir [NET]
  1646. See drivers/net/irda/sa1100_ir.c.
  1647. sbni= [NET] Granch SBNI12 leased line adapter
  1648. sc1200wdt= [HW,WDT] SC1200 WDT (watchdog) driver
  1649. Format: <io>[,<timeout>[,<isapnp>]]
  1650. scsi_debug_*= [SCSI]
  1651. See drivers/scsi/scsi_debug.c.
  1652. scsi_default_dev_flags=
  1653. [SCSI] SCSI default device flags
  1654. Format: <integer>
  1655. scsi_dev_flags= [SCSI] Black/white list entry for vendor and model
  1656. Format: <vendor>:<model>:<flags>
  1657. (flags are integer value)
  1658. scsi_logging_level= [SCSI] a bit mask of logging levels
  1659. See drivers/scsi/scsi_logging.h for bits. Also
  1660. settable via sysctl at dev.scsi.logging_level
  1661. (/proc/sys/dev/scsi/logging_level).
  1662. There is also a nice 'scsi_logging_level' script in the
  1663. S390-tools package, available for download at
  1664. http://www-128.ibm.com/developerworks/linux/linux390/s390-tools-1.5.4.html
  1665. scsi_mod.scan= [SCSI] sync (default) scans SCSI busses as they are
  1666. discovered. async scans them in kernel threads,
  1667. allowing boot to proceed. none ignores them, expecting
  1668. user space to do the scan.
  1669. security= [SECURITY] Choose a security module to enable at boot.
  1670. If this boot parameter is not specified, only the first
  1671. security module asking for security registration will be
  1672. loaded. An invalid security module name will be treated
  1673. as if no module has been chosen.
  1674. selinux= [SELINUX] Disable or enable SELinux at boot time.
  1675. Format: { "0" | "1" }
  1676. See security/selinux/Kconfig help text.
  1677. 0 -- disable.
  1678. 1 -- enable.
  1679. Default value is set via kernel config option.
  1680. If enabled at boot time, /selinux/disable can be used
  1681. later to disable prior to initial policy load.
  1682. serialnumber [BUGS=X86-32]
  1683. shapers= [NET]
  1684. Maximal number of shapers.
  1685. show_msr= [x86] show boot-time MSR settings
  1686. Format: { <integer> }
  1687. Show boot-time (BIOS-initialized) MSR settings.
  1688. The parameter means the number of CPUs to show,
  1689. for example 1 means boot CPU only.
  1690. sim710= [SCSI,HW]
  1691. See header of drivers/scsi/sim710.c.
  1692. simeth= [IA-64]
  1693. simscsi=
  1694. slram= [HW,MTD]
  1695. slub_debug[=options[,slabs]] [MM, SLUB]
  1696. Enabling slub_debug allows one to determine the
  1697. culprit if slab objects become corrupted. Enabling
  1698. slub_debug can create guard zones around objects and
  1699. may poison objects when not in use. Also tracks the
  1700. last alloc / free. For more information see
  1701. Documentation/vm/slub.txt.
  1702. slub_max_order= [MM, SLUB]
  1703. Determines the maximum allowed order for slabs.
  1704. A high setting may cause OOMs due to memory
  1705. fragmentation. For more information see
  1706. Documentation/vm/slub.txt.
  1707. slub_min_objects= [MM, SLUB]
  1708. The minimum number of objects per slab. SLUB will
  1709. increase the slab order up to slub_max_order to
  1710. generate a sufficiently large slab able to contain
  1711. the number of objects indicated. The higher the number
  1712. of objects the smaller the overhead of tracking slabs
  1713. and the less frequently locks need to be acquired.
  1714. For more information see Documentation/vm/slub.txt.
  1715. slub_min_order= [MM, SLUB]
  1716. Determines the mininum page order for slabs. Must be
  1717. lower than slub_max_order.
  1718. For more information see Documentation/vm/slub.txt.
  1719. slub_nomerge [MM, SLUB]
  1720. Disable merging of slabs with similar size. May be
  1721. necessary if there is some reason to distinguish
  1722. allocs to different slabs. Debug options disable
  1723. merging on their own.
  1724. For more information see Documentation/vm/slub.txt.
  1725. smart2= [HW]
  1726. Format: <io1>[,<io2>[,...,<io8>]]
  1727. smp-alt-once [X86-32,SMP] On a hotplug CPU system, only
  1728. attempt to substitute SMP alternatives once at boot.
  1729. smsc-ircc2.nopnp [HW] Don't use PNP to discover SMC devices
  1730. smsc-ircc2.ircc_cfg= [HW] Device configuration I/O port
  1731. smsc-ircc2.ircc_sir= [HW] SIR base I/O port
  1732. smsc-ircc2.ircc_fir= [HW] FIR base I/O port
  1733. smsc-ircc2.ircc_irq= [HW] IRQ line
  1734. smsc-ircc2.ircc_dma= [HW] DMA channel
  1735. smsc-ircc2.ircc_transceiver= [HW] Transceiver type:
  1736. 0: Toshiba Satellite 1800 (GP data pin select)
  1737. 1: Fast pin select (default)
  1738. 2: ATC IRMode
  1739. snd-ad1816a= [HW,ALSA]
  1740. snd-ad1848= [HW,ALSA]
  1741. snd-ali5451= [HW,ALSA]
  1742. snd-als100= [HW,ALSA]
  1743. snd-als4000= [HW,ALSA]
  1744. snd-azt2320= [HW,ALSA]
  1745. snd-cmi8330= [HW,ALSA]
  1746. snd-cmipci= [HW,ALSA]
  1747. snd-cs4231= [HW,ALSA]
  1748. snd-cs4232= [HW,ALSA]
  1749. snd-cs4236= [HW,ALSA]
  1750. snd-cs4281= [HW,ALSA]
  1751. snd-cs46xx= [HW,ALSA]
  1752. snd-dt019x= [HW,ALSA]
  1753. snd-dummy= [HW,ALSA]
  1754. snd-emu10k1= [HW,ALSA]
  1755. snd-ens1370= [HW,ALSA]
  1756. snd-ens1371= [HW,ALSA]
  1757. snd-es968= [HW,ALSA]
  1758. snd-es1688= [HW,ALSA]
  1759. snd-es18xx= [HW,ALSA]
  1760. snd-es1938= [HW,ALSA]
  1761. snd-es1968= [HW,ALSA]
  1762. snd-fm801= [HW,ALSA]
  1763. snd-gusclassic= [HW,ALSA]
  1764. snd-gusextreme= [HW,ALSA]
  1765. snd-gusmax= [HW,ALSA]
  1766. snd-hdsp= [HW,ALSA]
  1767. snd-ice1712= [HW,ALSA]
  1768. snd-intel8x0= [HW,ALSA]
  1769. snd-interwave= [HW,ALSA]
  1770. snd-interwave-stb=
  1771. [HW,ALSA]
  1772. snd-korg1212= [HW,ALSA]
  1773. snd-maestro3= [HW,ALSA]
  1774. snd-mpu401= [HW,ALSA]
  1775. snd-mtpav= [HW,ALSA]
  1776. snd-nm256= [HW,ALSA]
  1777. snd-opl3sa2= [HW,ALSA]
  1778. snd-opti92x-ad1848=
  1779. [HW,ALSA]
  1780. snd-opti92x-cs4231=
  1781. [HW,ALSA]
  1782. snd-opti93x= [HW,ALSA]
  1783. snd-pmac= [HW,ALSA]
  1784. snd-rme32= [HW,ALSA]
  1785. snd-rme96= [HW,ALSA]
  1786. snd-rme9652= [HW,ALSA]
  1787. snd-sb8= [HW,ALSA]
  1788. snd-sb16= [HW,ALSA]
  1789. snd-sbawe= [HW,ALSA]
  1790. snd-serial= [HW,ALSA]
  1791. snd-sgalaxy= [HW,ALSA]
  1792. snd-sonicvibes= [HW,ALSA]
  1793. snd-sun-amd7930=
  1794. [HW,ALSA]
  1795. snd-sun-cs4231= [HW,ALSA]
  1796. snd-trident= [HW,ALSA]
  1797. snd-usb-audio= [HW,ALSA,USB]
  1798. snd-via82xx= [HW,ALSA]
  1799. snd-virmidi= [HW,ALSA]
  1800. snd-wavefront= [HW,ALSA]
  1801. snd-ymfpci= [HW,ALSA]
  1802. softlockup_panic=
  1803. [KNL] Should the soft-lockup detector generate panics.
  1804. sonypi.*= [HW] Sony Programmable I/O Control Device driver
  1805. See Documentation/sonypi.txt
  1806. specialix= [HW,SERIAL] Specialix multi-serial port adapter
  1807. See Documentation/serial/specialix.txt.
  1808. spia_io_base= [HW,MTD]
  1809. spia_fio_base=
  1810. spia_pedr=
  1811. spia_peddr=
  1812. sscape= [HW,OSS]
  1813. Format: <io>,<irq>,<dma>,<mpu_io>,<mpu_irq>
  1814. st= [HW,SCSI] SCSI tape parameters (buffers, etc.)
  1815. See Documentation/scsi/st.txt.
  1816. stacktrace [FTRACE]
  1817. Enabled the stack tracer on boot up.
  1818. sti= [PARISC,HW]
  1819. Format: <num>
  1820. Set the STI (builtin display/keyboard on the HP-PARISC
  1821. machines) console (graphic card) which should be used
  1822. as the initial boot-console.
  1823. See also comment in drivers/video/console/sticore.c.
  1824. sti_font= [HW]
  1825. See comment in drivers/video/console/sticore.c.
  1826. stifb= [HW]
  1827. Format: bpp:<bpp1>[:<bpp2>[:<bpp3>...]]
  1828. sunrpc.pool_mode=
  1829. [NFS]
  1830. Control how the NFS server code allocates CPUs to
  1831. service thread pools. Depending on how many NICs
  1832. you have and where their interrupts are bound, this
  1833. option will affect which CPUs will do NFS serving.
  1834. Note: this parameter cannot be changed while the
  1835. NFS server is running.
  1836. auto the server chooses an appropriate mode
  1837. automatically using heuristics
  1838. global a single global pool contains all CPUs
  1839. percpu one pool for each CPU
  1840. pernode one pool for each NUMA node (equivalent
  1841. to global on non-NUMA machines)
  1842. swiotlb= [IA-64] Number of I/O TLB slabs
  1843. switches= [HW,M68k]
  1844. sym53c416= [HW,SCSI]
  1845. See header of drivers/scsi/sym53c416.c.
  1846. sysrq_always_enabled
  1847. [KNL]
  1848. Ignore sysrq setting - this boot parameter will
  1849. neutralize any effect of /proc/sys/kernel/sysrq.
  1850. Useful for debugging.
  1851. t128= [HW,SCSI]
  1852. See header of drivers/scsi/t128.c.
  1853. tdfx= [HW,DRM]
  1854. test_suspend= [SUSPEND]
  1855. Specify "mem" (for Suspend-to-RAM) or "standby" (for
  1856. standby suspend) as the system sleep state to briefly
  1857. enter during system startup. The system is woken from
  1858. this state using a wakeup-capable RTC alarm.
  1859. thash_entries= [KNL,NET]
  1860. Set number of hash buckets for TCP connection
  1861. thermal.act= [HW,ACPI]
  1862. -1: disable all active trip points in all thermal zones
  1863. <degrees C>: override all lowest active trip points
  1864. thermal.crt= [HW,ACPI]
  1865. -1: disable all critical trip points in all thermal zones
  1866. <degrees C>: override all critical trip points
  1867. thermal.nocrt= [HW,ACPI]
  1868. Set to disable actions on ACPI thermal zone
  1869. critical and hot trip points.
  1870. thermal.off= [HW,ACPI]
  1871. 1: disable ACPI thermal control
  1872. thermal.psv= [HW,ACPI]
  1873. -1: disable all passive trip points
  1874. <degrees C>: override all passive trip points to this
  1875. value
  1876. thermal.tzp= [HW,ACPI]
  1877. Specify global default ACPI thermal zone polling rate
  1878. <deci-seconds>: poll all this frequency
  1879. 0: no polling (default)
  1880. tmscsim= [HW,SCSI]
  1881. See comment before function dc390_setup() in
  1882. drivers/scsi/tmscsim.c.
  1883. topology= [S390]
  1884. Format: {off | on}
  1885. Specify if the kernel should make use of the cpu
  1886. topology informations if the hardware supports these.
  1887. The scheduler will make use of these informations and
  1888. e.g. base its process migration decisions on it.
  1889. Default is off.
  1890. tp720= [HW,PS2]
  1891. trace_buf_size=nn[KMG] [ftrace] will set tracing buffer size.
  1892. trix= [HW,OSS] MediaTrix AudioTrix Pro
  1893. Format:
  1894. <io>,<irq>,<dma>,<dma2>,<sb_io>,<sb_irq>,<sb_dma>,<mpu_io>,<mpu_irq>
  1895. tsc= Disable clocksource-must-verify flag for TSC.
  1896. Format: <string>
  1897. [x86] reliable: mark tsc clocksource as reliable, this
  1898. disables clocksource verification at runtime.
  1899. Used to enable high-resolution timer mode on older
  1900. hardware, and in virtualized environment.
  1901. turbografx.map[2|3]= [HW,JOY]
  1902. TurboGraFX parallel port interface
  1903. Format:
  1904. <port#>,<js1>,<js2>,<js3>,<js4>,<js5>,<js6>,<js7>
  1905. See also Documentation/input/joystick-parport.txt
  1906. u14-34f= [HW,SCSI] UltraStor 14F/34F SCSI host adapter
  1907. See header of drivers/scsi/u14-34f.c.
  1908. uart401= [HW,OSS]
  1909. Format: <io>,<irq>
  1910. uart6850= [HW,OSS]
  1911. Format: <io>,<irq>
  1912. uhci-hcd.ignore_oc=
  1913. [USB] Ignore overcurrent events (default N).
  1914. Some badly-designed motherboards generate lots of
  1915. bogus events, for ports that aren't wired to
  1916. anything. Set this parameter to avoid log spamming.
  1917. Note that genuine overcurrent events won't be
  1918. reported either.
  1919. unknown_nmi_panic
  1920. [X86]
  1921. Set unknown_nmi_panic=1 early on boot.
  1922. usbcore.autosuspend=
  1923. [USB] The autosuspend time delay (in seconds) used
  1924. for newly-detected USB devices (default 2). This
  1925. is the time required before an idle device will be
  1926. autosuspended. Devices for which the delay is set
  1927. to a negative value won't be autosuspended at all.
  1928. usbcore.usbfs_snoop=
  1929. [USB] Set to log all usbfs traffic (default 0 = off).
  1930. usbcore.blinkenlights=
  1931. [USB] Set to cycle leds on hubs (default 0 = off).
  1932. usbcore.old_scheme_first=
  1933. [USB] Start with the old device initialization
  1934. scheme (default 0 = off).
  1935. usbcore.use_both_schemes=
  1936. [USB] Try the other device initialization scheme
  1937. if the first one fails (default 1 = enabled).
  1938. usbcore.initial_descriptor_timeout=
  1939. [USB] Specifies timeout for the initial 64-byte
  1940. USB_REQ_GET_DESCRIPTOR request in milliseconds
  1941. (default 5000 = 5.0 seconds).
  1942. usbhid.mousepoll=
  1943. [USBHID] The interval which mice are to be polled at.
  1944. usb-storage.delay_use=
  1945. [UMS] The delay in seconds before a new device is
  1946. scanned for Logical Units (default 5).
  1947. usb-storage.quirks=
  1948. [UMS] A list of quirks entries to supplement or
  1949. override the built-in unusual_devs list. List
  1950. entries are separated by commas. Each entry has
  1951. the form VID:PID:Flags where VID and PID are Vendor
  1952. and Product ID values (4-digit hex numbers) and
  1953. Flags is a set of characters, each corresponding
  1954. to a common usb-storage quirk flag as follows:
  1955. a = SANE_SENSE (collect more than 18 bytes
  1956. of sense data);
  1957. c = FIX_CAPACITY (decrease the reported
  1958. device capacity by one sector);
  1959. h = CAPACITY_HEURISTICS (decrease the
  1960. reported device capacity by one
  1961. sector if the number is odd);
  1962. i = IGNORE_DEVICE (don't bind to this
  1963. device);
  1964. l = NOT_LOCKABLE (don't try to lock and
  1965. unlock ejectable media);
  1966. m = MAX_SECTORS_64 (don't transfer more
  1967. than 64 sectors = 32 KB at a time);
  1968. o = CAPACITY_OK (accept the capacity
  1969. reported by the device);
  1970. r = IGNORE_RESIDUE (the device reports
  1971. bogus residue values);
  1972. s = SINGLE_LUN (the device has only one
  1973. Logical Unit);
  1974. w = NO_WP_DETECT (don't test whether the
  1975. medium is write-protected).
  1976. Example: quirks=0419:aaf5:rl,0421:0433:rc
  1977. vdso= [X86,SH]
  1978. vdso=2: enable compat VDSO (default with COMPAT_VDSO)
  1979. vdso=1: enable VDSO (default)
  1980. vdso=0: disable VDSO mapping
  1981. vdso32= [X86]
  1982. vdso32=2: enable compat VDSO (default with COMPAT_VDSO)
  1983. vdso32=1: enable 32-bit VDSO (default)
  1984. vdso32=0: disable 32-bit VDSO mapping
  1985. vector= [IA-64,SMP]
  1986. vector=percpu: enable percpu vector domain
  1987. video= [FB] Frame buffer configuration
  1988. See Documentation/fb/modedb.txt.
  1989. vga= [BOOT,X86-32] Select a particular video mode
  1990. See Documentation/x86/boot.txt and
  1991. Documentation/svga.txt.
  1992. Use vga=ask for menu.
  1993. This is actually a boot loader parameter; the value is
  1994. passed to the kernel using a special protocol.
  1995. vmalloc=nn[KMG] [KNL,BOOT] Forces the vmalloc area to have an exact
  1996. size of <nn>. This can be used to increase the
  1997. minimum size (128MB on x86). It can also be used to
  1998. decrease the size and leave more room for directly
  1999. mapped kernel RAM.
  2000. vmhalt= [KNL,S390] Perform z/VM CP command after system halt.
  2001. Format: <command>
  2002. vmpanic= [KNL,S390] Perform z/VM CP command after kernel panic.
  2003. Format: <command>
  2004. vmpoff= [KNL,S390] Perform z/VM CP command after power off.
  2005. Format: <command>
  2006. vt.default_blu= [VT]
  2007. Format: <blue0>,<blue1>,<blue2>,...,<blue15>
  2008. Change the default blue palette of the console.
  2009. This is a 16-member array composed of values
  2010. ranging from 0-255.
  2011. vt.default_grn= [VT]
  2012. Format: <green0>,<green1>,<green2>,...,<green15>
  2013. Change the default green palette of the console.
  2014. This is a 16-member array composed of values
  2015. ranging from 0-255.
  2016. vt.default_red= [VT]
  2017. Format: <red0>,<red1>,<red2>,...,<red15>
  2018. Change the default red palette of the console.
  2019. This is a 16-member array composed of values
  2020. ranging from 0-255.
  2021. vt.default_utf8=
  2022. [VT]
  2023. Format=<0|1>
  2024. Set system-wide default UTF-8 mode for all tty's.
  2025. Default is 1, i.e. UTF-8 mode is enabled for all
  2026. newly opened terminals.
  2027. waveartist= [HW,OSS]
  2028. Format: <io>,<irq>,<dma>,<dma2>
  2029. wd33c93= [HW,SCSI]
  2030. See header of drivers/scsi/wd33c93.c.
  2031. wd7000= [HW,SCSI]
  2032. See header of drivers/scsi/wd7000.c.
  2033. wdt= [WDT] Watchdog
  2034. See Documentation/watchdog/wdt.txt.
  2035. x2apic_phys [X86-64,APIC] Use x2apic physical mode instead of
  2036. default x2apic cluster mode on platforms
  2037. supporting x2apic.
  2038. xd= [HW,XT] Original XT pre-IDE (RLL encoded) disks.
  2039. xd_geo= See header of drivers/block/xd.c.
  2040. xirc2ps_cs= [NET,PCMCIA]
  2041. Format:
  2042. <irq>,<irq_mask>,<io>,<full_duplex>,<do_sound>,<lockup_hack>[,<irq2>[,<irq3>[,<irq4>]]]
  2043. ______________________________________________________________________
  2044. TODO:
  2045. Add documentation for ALSA options.
  2046. Add more DRM drivers.