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Documentation / kernel-parameters.txt

Based on kernel version 2.6.30. Page generated on 2009-06-11 10:12 EST.

1	                          Kernel Parameters
2	                          ~~~~~~~~~~~~~~~~~
3	
4	The following is a consolidated list of the kernel parameters as implemented
5	(mostly) by the __setup() macro and sorted into English Dictionary order
6	(defined as ignoring all punctuation and sorting digits before letters in a
7	case insensitive manner), and with descriptions where known.
8	
9	Module parameters for loadable modules are specified only as the
10	parameter name with optional '=' and value as appropriate, such as:
11	
12		modprobe usbcore blinkenlights=1
13	
14	Module parameters for modules that are built into the kernel image
15	are specified on the kernel command line with the module name plus
16	'.' plus parameter name, with '=' and value if appropriate, such as:
17	
18		usbcore.blinkenlights=1
19	
20	Hyphens (dashes) and underscores are equivalent in parameter names, so
21		log_buf_len=1M print-fatal-signals=1
22	can also be entered as
23		log-buf-len=1M print_fatal_signals=1
24	
25	
26	This document may not be entirely up to date and comprehensive. The command
27	"modinfo -p ${modulename}" shows a current list of all parameters of a loadable
28	module. Loadable modules, after being loaded into the running kernel, also
29	reveal their parameters in /sys/module/${modulename}/parameters/. Some of these
30	parameters may be changed at runtime by the command
31	"echo -n ${value} > /sys/module/${modulename}/parameters/${parm}".
32	
33	The parameters listed below are only valid if certain kernel build options were
34	enabled and if respective hardware is present. The text in square brackets at
35	the beginning of each description states the restrictions within which a
36	parameter is applicable:
37	
38		ACPI	ACPI support is enabled.
39		AGP	AGP (Accelerated Graphics Port) is enabled.
40		ALSA	ALSA sound support is enabled.
41		APIC	APIC support is enabled.
42		APM	Advanced Power Management support is enabled.
43		AVR32	AVR32 architecture is enabled.
44		AX25	Appropriate AX.25 support is enabled.
45		BLACKFIN Blackfin architecture is enabled.
46		DRM	Direct Rendering Management support is enabled.
47		EDD	BIOS Enhanced Disk Drive Services (EDD) is enabled
48		EFI	EFI Partitioning (GPT) is enabled
49		EIDE	EIDE/ATAPI support is enabled.
50		FB	The frame buffer device is enabled.
51		HW	Appropriate hardware is enabled.
52		IA-64	IA-64 architecture is enabled.
53		IMA     Integrity measurement architecture is enabled.
54		IOSCHED	More than one I/O scheduler is enabled.
55		IP_PNP	IP DHCP, BOOTP, or RARP is enabled.
56		ISAPNP	ISA PnP code is enabled.
57		ISDN	Appropriate ISDN support is enabled.
58		JOY	Appropriate joystick support is enabled.
59		KMEMTRACE kmemtrace is enabled.
60		LIBATA  Libata driver is enabled
61		LP	Printer support is enabled.
62		LOOP	Loopback device support is enabled.
63		M68k	M68k architecture is enabled.
64				These options have more detailed description inside of
65				Documentation/m68k/kernel-options.txt.
66		MCA	MCA bus support is enabled.
67		MDA	MDA console support is enabled.
68		MOUSE	Appropriate mouse support is enabled.
69		MSI	Message Signaled Interrupts (PCI).
70		MTD	MTD (Memory Technology Device) support is enabled.
71		NET	Appropriate network support is enabled.
72		NUMA	NUMA support is enabled.
73		GENERIC_TIME The generic timeofday code is enabled.
74		NFS	Appropriate NFS support is enabled.
75		OSS	OSS sound support is enabled.
76		PV_OPS	A paravirtualized kernel is enabled.
77		PARIDE	The ParIDE (parallel port IDE) subsystem is enabled.
78		PARISC	The PA-RISC architecture is enabled.
79		PCI	PCI bus support is enabled.
80		PCIE	PCI Express support is enabled.
81		PCMCIA	The PCMCIA subsystem is enabled.
82		PNP	Plug & Play support is enabled.
83		PPC	PowerPC architecture is enabled.
84		PPT	Parallel port support is enabled.
85		PS2	Appropriate PS/2 support is enabled.
86		RAM	RAM disk support is enabled.
87		ROOTPLUG The example Root Plug LSM is enabled.
88		S390	S390 architecture is enabled.
89		SCSI	Appropriate SCSI support is enabled.
90				A lot of drivers has their options described inside of
91				Documentation/scsi/.
92		SECURITY Different security models are enabled.
93		SELINUX SELinux support is enabled.
94		SERIAL	Serial support is enabled.
95		SH	SuperH architecture is enabled.
96		SMP	The kernel is an SMP kernel.
97		SPARC	Sparc architecture is enabled.
98		SWSUSP	Software suspend (hibernation) is enabled.
99		SUSPEND	System suspend states are enabled.
100		FTRACE	Function tracing enabled.
101		TS	Appropriate touchscreen support is enabled.
102		UMS	USB Mass Storage support is enabled.
103		USB	USB support is enabled.
104		USBHID	USB Human Interface Device support is enabled.
105		V4L	Video For Linux support is enabled.
106		VGA	The VGA console has been enabled.
107		VT	Virtual terminal support is enabled.
108		WDT	Watchdog support is enabled.
109		XT	IBM PC/XT MFM hard disk support is enabled.
110		X86-32	X86-32, aka i386 architecture is enabled.
111		X86-64	X86-64 architecture is enabled.
112				More X86-64 boot options can be found in
113				Documentation/x86/x86_64/boot-options.txt .
114		X86	Either 32bit or 64bit x86 (same as X86-32+X86-64)
115	
116	In addition, the following text indicates that the option:
117	
118		BUGS=	Relates to possible processor bugs on the said processor.
119		KNL	Is a kernel start-up parameter.
120		BOOT	Is a boot loader parameter.
121	
122	Parameters denoted with BOOT are actually interpreted by the boot
123	loader, and have no meaning to the kernel directly.
124	Do not modify the syntax of boot loader parameters without extreme
125	need or coordination with <Documentation/x86/boot.txt>.
126	
127	There are also arch-specific kernel-parameters not documented here.
128	See for example <Documentation/x86/x86_64/boot-options.txt>.
129	
130	Note that ALL kernel parameters listed below are CASE SENSITIVE, and that
131	a trailing = on the name of any parameter states that that parameter will
132	be entered as an environment variable, whereas its absence indicates that
133	it will appear as a kernel argument readable via /proc/cmdline by programs
134	running once the system is up.
135	
136	The number of kernel parameters is not limited, but the length of the
137	complete command line (parameters including spaces etc.) is limited to
138	a fixed number of characters. This limit depends on the architecture
139	and is between 256 and 4096 characters. It is defined in the file
140	./include/asm/setup.h as COMMAND_LINE_SIZE.
141	
142	
143		acpi=		[HW,ACPI,X86]
144				Advanced Configuration and Power Interface
145				Format: { force | off | ht | strict | noirq | rsdt }
146				force -- enable ACPI if default was off
147				off -- disable ACPI if default was on
148				noirq -- do not use ACPI for IRQ routing
149				ht -- run only enough ACPI to enable Hyper Threading
150				strict -- Be less tolerant of platforms that are not
151					strictly ACPI specification compliant.
152				rsdt -- prefer RSDT over (default) XSDT
153	
154				See also Documentation/power/pm.txt, pci=noacpi
155	
156		acpi_apic_instance=	[ACPI, IOAPIC]
157				Format: <int>
158				2: use 2nd APIC table, if available
159				1,0: use 1st APIC table
160				default: 0
161	
162		acpi_backlight=	[HW,ACPI]
163				acpi_backlight=vendor
164				acpi_backlight=video
165				If set to vendor, prefer vendor specific driver
166				(e.g. thinkpad_acpi, sony_acpi, etc.) instead
167				of the ACPI video.ko driver.
168	
169		acpi.debug_layer=	[HW,ACPI,ACPI_DEBUG]
170		acpi.debug_level=	[HW,ACPI,ACPI_DEBUG]
171				Format: <int>
172				CONFIG_ACPI_DEBUG must be enabled to produce any ACPI
173				debug output.  Bits in debug_layer correspond to a
174				_COMPONENT in an ACPI source file, e.g.,
175				    #define _COMPONENT ACPI_PCI_COMPONENT
176				Bits in debug_level correspond to a level in
177				ACPI_DEBUG_PRINT statements, e.g.,
178				    ACPI_DEBUG_PRINT((ACPI_DB_INFO, ...
179				The debug_level mask defaults to "info".  See
180				Documentation/acpi/debug.txt for more information about
181				debug layers and levels.
182	
183				Enable processor driver info messages:
184				    acpi.debug_layer=0x20000000
185				Enable PCI/PCI interrupt routing info messages:
186				    acpi.debug_layer=0x400000
187				Enable AML "Debug" output, i.e., stores to the Debug
188				object while interpreting AML:
189				    acpi.debug_layer=0xffffffff acpi.debug_level=0x2
190				Enable all messages related to ACPI hardware:
191				    acpi.debug_layer=0x2 acpi.debug_level=0xffffffff
192	
193				Some values produce so much output that the system is
194				unusable.  The "log_buf_len" parameter may be useful
195				if you need to capture more output.
196	
197		acpi_display_output=	[HW,ACPI]
198				acpi_display_output=vendor
199				acpi_display_output=video
200				See above.
201	
202		acpi_irq_balance [HW,ACPI]
203				ACPI will balance active IRQs
204				default in APIC mode
205	
206		acpi_irq_nobalance [HW,ACPI]
207				ACPI will not move active IRQs (default)
208				default in PIC mode
209	
210		acpi_irq_isa=	[HW,ACPI] If irq_balance, mark listed IRQs used by ISA
211				Format: <irq>,<irq>...
212	
213		acpi_irq_pci=	[HW,ACPI] If irq_balance, clear listed IRQs for
214				use by PCI
215				Format: <irq>,<irq>...
216	
217		acpi_no_auto_ssdt	[HW,ACPI] Disable automatic loading of SSDT
218	
219		acpi_os_name=	[HW,ACPI] Tell ACPI BIOS the name of the OS
220				Format: To spoof as Windows 98: ="Microsoft Windows"
221	
222		acpi_osi=	[HW,ACPI] Modify list of supported OS interface strings
223				acpi_osi="string1"	# add string1 -- only one string
224				acpi_osi="!string2"	# remove built-in string2
225				acpi_osi=		# disable all strings
226	
227		acpi_pm_good	[X86]
228				Override the pmtimer bug detection: force the kernel
229				to assume that this machine's pmtimer latches its value
230				and always returns good values.
231	
232	 	acpi.power_nocheck=	[HW,ACPI]
233	 			Format: 1/0 enable/disable the check of power state.
234	 			On some bogus BIOS the _PSC object/_STA object of
235	 			power resource can't return the correct device power
236	 			state. In such case it is unneccessary to check its
237	 			power state again in power transition.
238	 			1 : disable the power state check
239	
240		acpi_sci=	[HW,ACPI] ACPI System Control Interrupt trigger mode
241				Format: { level | edge | high | low }
242	
243		acpi_serialize	[HW,ACPI] force serialization of AML methods
244	
245		acpi_skip_timer_override [HW,ACPI]
246				Recognize and ignore IRQ0/pin2 Interrupt Override.
247				For broken nForce2 BIOS resulting in XT-PIC timer.
248	
249		acpi_sleep=	[HW,ACPI] Sleep options
250				Format: { s3_bios, s3_mode, s3_beep, s4_nohwsig,
251					  old_ordering, s4_nonvs }
252				See Documentation/power/video.txt for information on
253				s3_bios and s3_mode.
254				s3_beep is for debugging; it makes the PC's speaker beep
255				as soon as the kernel's real-mode entry point is called.
256				s4_nohwsig prevents ACPI hardware signature from being
257				used during resume from hibernation.
258				old_ordering causes the ACPI 1.0 ordering of the _PTS
259				control method, with respect to putting devices into
260				low power states, to be enforced (the ACPI 2.0 ordering
261				of _PTS is used by default).
262				s4_nonvs prevents the kernel from saving/restoring the
263				ACPI NVS memory during hibernation.
264	
265		acpi_use_timer_override [HW,ACPI]
266				Use timer override. For some broken Nvidia NF5 boards
267				that require a timer override, but don't have HPET
268	
269		acpi_enforce_resources=	[ACPI]
270				{ strict | lax | no }
271				Check for resource conflicts between native drivers
272				and ACPI OperationRegions (SystemIO and SystemMemory
273				only). IO ports and memory declared in ACPI might be
274				used by the ACPI subsystem in arbitrary AML code and
275				can interfere with legacy drivers.
276				strict (default): access to resources claimed by ACPI
277				is denied; legacy drivers trying to access reserved
278				resources will fail to bind to device using them.
279				lax: access to resources claimed by ACPI is allowed;
280				legacy drivers trying to access reserved resources
281				will bind successfully but a warning message is logged.
282				no: ACPI OperationRegions are not marked as reserved,
283				no further checks are performed.
284	
285		ad1848=		[HW,OSS]
286				Format: <io>,<irq>,<dma>,<dma2>,<type>
287	
288		add_efi_memmap	[EFI; X86] Include EFI memory map in
289				kernel's map of available physical RAM.
290	
291		advansys=	[HW,SCSI]
292				See header of drivers/scsi/advansys.c.
293	
294		advwdt=		[HW,WDT] Advantech WDT
295				Format: <iostart>,<iostop>
296	
297		aedsp16=	[HW,OSS] Audio Excel DSP 16
298				Format: <io>,<irq>,<dma>,<mss_io>,<mpu_io>,<mpu_irq>
299				See also header of sound/oss/aedsp16.c.
300	
301		agp=		[AGP]
302				{ off | try_unsupported }
303				off: disable AGP support
304				try_unsupported: try to drive unsupported chipsets
305					(may crash computer or cause data corruption)
306	
307		aha152x=	[HW,SCSI]
308				See Documentation/scsi/aha152x.txt.
309	
310		aha1542=	[HW,SCSI]
311				Format: <portbase>[,<buson>,<busoff>[,<dmaspeed>]]
312	
313		aic7xxx=	[HW,SCSI]
314				See Documentation/scsi/aic7xxx.txt.
315	
316		aic79xx=	[HW,SCSI]
317				See Documentation/scsi/aic79xx.txt.
318	
319		amd_iommu=	[HW,X86-84]
320				Pass parameters to the AMD IOMMU driver in the system.
321				Possible values are:
322				isolate - enable device isolation (each device, as far
323				          as possible, will get its own protection
324				          domain) [default]
325				share - put every device behind one IOMMU into the
326					same protection domain
327				fullflush - enable flushing of IO/TLB entries when
328					    they are unmapped. Otherwise they are
329					    flushed before they will be reused, which
330					    is a lot of faster
331	
332		amd_iommu_size= [HW,X86-64]
333				Define the size of the aperture for the AMD IOMMU
334				driver. Possible values are:
335				'32M', '64M' (default), '128M', '256M', '512M', '1G'
336	
337		amijoy.map=	[HW,JOY] Amiga joystick support
338				Map of devices attached to JOY0DAT and JOY1DAT
339				Format: <a>,<b>
340				See also Documentation/kernel/input/joystick.txt
341	
342		analog.map=	[HW,JOY] Analog joystick and gamepad support
343				Specifies type or capabilities of an analog joystick
344				connected to one of 16 gameports
345				Format: <type1>,<type2>,..<type16>
346	
347		apc=		[HW,SPARC]
348				Power management functions (SPARCstation-4/5 + deriv.)
349				Format: noidle
350				Disable APC CPU standby support. SPARCstation-Fox does
351				not play well with APC CPU idle - disable it if you have
352				APC and your system crashes randomly.
353	
354		apic=		[APIC,X86-32] Advanced Programmable Interrupt Controller
355				Change the output verbosity whilst booting
356				Format: { quiet (default) | verbose | debug }
357				Change the amount of debugging information output
358				when initialising the APIC and IO-APIC components.
359	
360		apm=		[APM] Advanced Power Management
361				See header of arch/x86/kernel/apm_32.c.
362	
363		arcrimi=	[HW,NET] ARCnet - "RIM I" (entirely mem-mapped) cards
364				Format: <io>,<irq>,<nodeID>
365	
366		ataflop=	[HW,M68k]
367	
368		atarimouse=	[HW,MOUSE] Atari Mouse
369	
370		atascsi=	[HW,SCSI] Atari SCSI
371	
372		atkbd.extra=	[HW] Enable extra LEDs and keys on IBM RapidAccess,
373				EzKey and similar keyboards
374	
375		atkbd.reset=	[HW] Reset keyboard during initialization
376	
377		atkbd.set=	[HW] Select keyboard code set
378				Format: <int> (2 = AT (default), 3 = PS/2)
379	
380		atkbd.scroll=	[HW] Enable scroll wheel on MS Office and similar
381				keyboards
382	
383		atkbd.softraw=	[HW] Choose between synthetic and real raw mode
384				Format: <bool> (0 = real, 1 = synthetic (default))
385	
386		atkbd.softrepeat= [HW]
387				Use software keyboard repeat
388	
389		autotest	[IA64]
390	
391		baycom_epp=	[HW,AX25]
392				Format: <io>,<mode>
393	
394		baycom_par=	[HW,AX25] BayCom Parallel Port AX.25 Modem
395				Format: <io>,<mode>
396				See header of drivers/net/hamradio/baycom_par.c.
397	
398		baycom_ser_fdx=	[HW,AX25]
399				BayCom Serial Port AX.25 Modem (Full Duplex Mode)
400				Format: <io>,<irq>,<mode>[,<baud>]
401				See header of drivers/net/hamradio/baycom_ser_fdx.c.
402	
403		baycom_ser_hdx=	[HW,AX25]
404				BayCom Serial Port AX.25 Modem (Half Duplex Mode)
405				Format: <io>,<irq>,<mode>
406				See header of drivers/net/hamradio/baycom_ser_hdx.c.
407	
408		boot_delay=	Milliseconds to delay each printk during boot.
409				Values larger than 10 seconds (10000) are changed to
410				no delay (0).
411				Format: integer
412	
413		bootmem_debug	[KNL] Enable bootmem allocator debug messages.
414	
415		bttv.card=	[HW,V4L] bttv (bt848 + bt878 based grabber cards)
416		bttv.radio=	Most important insmod options are available as
417				kernel args too.
418		bttv.pll=	See Documentation/video4linux/bttv/Insmod-options
419		bttv.tuner=	and Documentation/video4linux/bttv/CARDLIST
420	
421		BusLogic=	[HW,SCSI]
422				See drivers/scsi/BusLogic.c, comment before function
423				BusLogic_ParseDriverOptions().
424	
425		c101=		[NET] Moxa C101 synchronous serial card
426	
427		cachesize=	[BUGS=X86-32] Override level 2 CPU cache size detection.
428				Sometimes CPU hardware bugs make them report the cache
429				size incorrectly. The kernel will attempt work arounds
430				to fix known problems, but for some CPUs it is not
431				possible to determine what the correct size should be.
432				This option provides an override for these situations.
433	
434		capability.disable=
435				[SECURITY] Disable capabilities.  This would normally
436				be used only if an alternative security model is to be
437				configured.  Potentially dangerous and should only be
438				used if you are entirely sure of the consequences.
439	
440		ccw_timeout_log [S390]
441				See Documentation/s390/CommonIO for details.
442	
443		cgroup_disable= [KNL] Disable a particular controller
444				Format: {name of the controller(s) to disable}
445					{Currently supported controllers - "memory"}
446	
447		checkreqprot	[SELINUX] Set initial checkreqprot flag value.
448				Format: { "0" | "1" }
449				See security/selinux/Kconfig help text.
450				0 -- check protection applied by kernel (includes
451					any implied execute protection).
452				1 -- check protection requested by application.
453				Default value is set via a kernel config option.
454				Value can be changed at runtime via
455					/selinux/checkreqprot.
456	
457		cio_ignore=	[S390]
458				See Documentation/s390/CommonIO for details.
459	
460		clock=		[BUGS=X86-32, HW] gettimeofday clocksource override.
461				[Deprecated]
462				Forces specified clocksource (if available) to be used
463				when calculating gettimeofday(). If specified
464				clocksource is not available, it defaults to PIT.
465				Format: { pit | tsc | cyclone | pmtmr }
466	
467		clocksource=	[GENERIC_TIME] Override the default clocksource
468				Format: <string>
469				Override the default clocksource and use the clocksource
470				with the name specified.
471				Some clocksource names to choose from, depending on
472				the platform:
473				[all] jiffies (this is the base, fallback clocksource)
474				[ACPI] acpi_pm
475				[ARM] imx_timer1,OSTS,netx_timer,mpu_timer2,
476					pxa_timer,timer3,32k_counter,timer0_1
477				[AVR32] avr32
478				[X86-32] pit,hpet,tsc,vmi-timer;
479					scx200_hrt on Geode; cyclone on IBM x440
480				[MIPS] MIPS
481				[PARISC] cr16
482				[S390] tod
483				[SH] SuperH
484				[SPARC64] tick
485				[X86-64] hpet,tsc
486	
487		clearcpuid=BITNUM [X86]
488				Disable CPUID feature X for the kernel. See
489				arch/x86/include/asm/cpufeature.h for the valid bit
490				numbers. Note the Linux specific bits are not necessarily
491				stable over kernel options, but the vendor specific
492				ones should be.
493				Also note that user programs calling CPUID directly
494				or using the feature without checking anything
495				will still see it. This just prevents it from
496				being used by the kernel or shown in /proc/cpuinfo.
497				Also note the kernel might malfunction if you disable
498				some critical bits.
499	
500		code_bytes	[X86] How many bytes of object code to print
501				in an oops report.
502				Range: 0 - 8192
503				Default: 64
504	
505		com20020=	[HW,NET] ARCnet - COM20020 chipset
506				Format:
507				<io>[,<irq>[,<nodeID>[,<backplane>[,<ckp>[,<timeout>]]]]]
508	
509		com90io=	[HW,NET] ARCnet - COM90xx chipset (IO-mapped buffers)
510				Format: <io>[,<irq>]
511	
512		com90xx=	[HW,NET]
513				ARCnet - COM90xx chipset (memory-mapped buffers)
514				Format: <io>[,<irq>[,<memstart>]]
515	
516		condev=		[HW,S390] console device
517		conmode=
518	
519		console=	[KNL] Output console device and options.
520	
521			tty<n>	Use the virtual console device <n>.
522	
523			ttyS<n>[,options]
524			ttyUSB0[,options]
525				Use the specified serial port.  The options are of
526				the form "bbbbpnf", where "bbbb" is the baud rate,
527				"p" is parity ("n", "o", or "e"), "n" is number of
528				bits, and "f" is flow control ("r" for RTS or
529				omit it).  Default is "9600n8".
530	
531				See Documentation/serial-console.txt for more
532				information.  See
533				Documentation/networking/netconsole.txt for an
534				alternative.
535	
536			uart[8250],io,<addr>[,options]
537			uart[8250],mmio,<addr>[,options]
538				Start an early, polled-mode console on the 8250/16550
539				UART at the specified I/O port or MMIO address,
540				switching to the matching ttyS device later.  The
541				options are the same as for ttyS, above.
542	
543	                If the device connected to the port is not a TTY but a braille
544	                device, prepend "brl," before the device type, for instance
545				console=brl,ttyS0
546			For now, only VisioBraille is supported.
547	
548		coredump_filter=
549				[KNL] Change the default value for
550				/proc/<pid>/coredump_filter.
551				See also Documentation/filesystems/proc.txt.
552	
553		cpcihp_generic=	[HW,PCI] Generic port I/O CompactPCI driver
554				Format:
555				<first_slot>,<last_slot>,<port>,<enum_bit>[,<debug>]
556	
557		crashkernel=nn[KMG]@ss[KMG]
558				[KNL] Reserve a chunk of physical memory to
559				hold a kernel to switch to with kexec on panic.
560	
561		crashkernel=range1:size1[,range2:size2,...][@offset]
562				[KNL] Same as above, but depends on the memory
563				in the running system. The syntax of range is
564				start-[end] where start and end are both
565				a memory unit (amount[KMG]). See also
566				Documentation/kdump/kdump.txt for a example.
567	
568		cs89x0_dma=	[HW,NET]
569				Format: <dma>
570	
571		cs89x0_media=	[HW,NET]
572				Format: { rj45 | aui | bnc }
573	
574		dasd=		[HW,NET]
575				See header of drivers/s390/block/dasd_devmap.c.
576	
577		db9.dev[2|3]=	[HW,JOY] Multisystem joystick support via parallel port
578				(one device per port)
579				Format: <port#>,<type>
580				See also Documentation/input/joystick-parport.txt
581	
582		debug		[KNL] Enable kernel debugging (events log level).
583	
584		debug_locks_verbose=
585				[KNL] verbose self-tests
586				Format=<0|1>
587				Print debugging info while doing the locking API
588				self-tests.
589				We default to 0 (no extra messages), setting it to
590				1 will print _a lot_ more information - normally
591				only useful to kernel developers.
592	
593		debug_objects	[KNL] Enable object debugging
594	
595		no_debug_objects
596				[KNL] Disable object debugging
597	
598		debugpat	[X86] Enable PAT debugging
599	
600		decnet.addr=	[HW,NET]
601				Format: <area>[,<node>]
602				See also Documentation/networking/decnet.txt.
603	
604		default_hugepagesz=
605				[same as hugepagesz=] The size of the default
606				HugeTLB page size. This is the size represented by
607				the legacy /proc/ hugepages APIs, used for SHM, and
608				default size when mounting hugetlbfs filesystems.
609				Defaults to the default architecture's huge page size
610				if not specified.
611	
612		dhash_entries=	[KNL]
613				Set number of hash buckets for dentry cache.
614	
615		digi=		[HW,SERIAL]
616				IO parameters + enable/disable command.
617	
618		digiepca=	[HW,SERIAL]
619				See drivers/char/README.epca and
620				Documentation/serial/digiepca.txt.
621	
622		disable_mtrr_cleanup [X86]
623				The kernel tries to adjust MTRR layout from continuous
624				to discrete, to make X server driver able to add WB
625				entry later. This parameter disables that.
626	
627		disable_mtrr_trim [X86, Intel and AMD only]
628				By default the kernel will trim any uncacheable
629				memory out of your available memory pool based on
630				MTRR settings.  This parameter disables that behavior,
631				possibly causing your machine to run very slowly.
632	
633		disable_timer_pin_1 [X86]
634				Disable PIN 1 of APIC timer
635				Can be useful to work around chipset bugs.
636	
637		dmasound=	[HW,OSS] Sound subsystem buffers
638	
639		dma_debug=off	If the kernel is compiled with DMA_API_DEBUG support,
640				this option disables the debugging code at boot.
641	
642		dma_debug_entries=<number>
643				This option allows to tune the number of preallocated
644				entries for DMA-API debugging code. One entry is
645				required per DMA-API allocation. Use this if the
646				DMA-API debugging code disables itself because the
647				architectural default is too low.
648	
649		dscc4.setup=	[NET]
650	
651		dtc3181e=	[HW,SCSI]
652	
653		dynamic_printk	Enables pr_debug()/dev_dbg() calls if
654				CONFIG_DYNAMIC_PRINTK_DEBUG has been enabled.
655				These can also be switched on/off via
656				<debugfs>/dynamic_printk/modules
657	
658		earlycon=	[KNL] Output early console device and options.
659			uart[8250],io,<addr>[,options]
660			uart[8250],mmio,<addr>[,options]
661				Start an early, polled-mode console on the 8250/16550
662				UART at the specified I/O port or MMIO address.
663				The options are the same as for ttyS, above.
664	
665		earlyprintk=	[X86,SH,BLACKFIN]
666				earlyprintk=vga
667				earlyprintk=serial[,ttySn[,baudrate]]
668				earlyprintk=dbgp
669	
670				Append ",keep" to not disable it when the real console
671				takes over.
672	
673				Only vga or serial or usb debug port at a time.
674	
675				Currently only ttyS0 and ttyS1 are supported.
676	
677				Interaction with the standard serial driver is not
678				very good.
679	
680				The VGA output is eventually overwritten by the real
681				console.
682	
683		eata=		[HW,SCSI]
684	
685		edd=		[EDD]
686				Format: {"off" | "on" | "skip[mbr]"}
687	
688		eisa_irq_edge=	[PARISC,HW]
689				See header of drivers/parisc/eisa.c.
690	
691		elanfreq=	[X86-32]
692				See comment before function elanfreq_setup() in
693				arch/x86/kernel/cpu/cpufreq/elanfreq.c.
694	
695		elevator=	[IOSCHED]
696				Format: {"anticipatory" | "cfq" | "deadline" | "noop"}
697				See Documentation/block/as-iosched.txt and
698				Documentation/block/deadline-iosched.txt for details.
699	
700		elfcorehdr=	[IA64,PPC,SH,X86]
701				Specifies physical address of start of kernel core
702				image elf header. Generally kexec loader will
703				pass this option to capture kernel.
704				See Documentation/kdump/kdump.txt for details.
705	
706		enable_mtrr_cleanup [X86]
707				The kernel tries to adjust MTRR layout from continuous
708				to discrete, to make X server driver able to add WB
709				entry later. This parameter enables that.
710	
711		enable_timer_pin_1 [X86]
712				Enable PIN 1 of APIC timer
713				Can be useful to work around chipset bugs
714				(in particular on some ATI chipsets).
715				The kernel tries to set a reasonable default.
716	
717		enforcing	[SELINUX] Set initial enforcing status.
718				Format: {"0" | "1"}
719				See security/selinux/Kconfig help text.
720				0 -- permissive (log only, no denials).
721				1 -- enforcing (deny and log).
722				Default value is 0.
723				Value can be changed at runtime via /selinux/enforce.
724	
725		ether=		[HW,NET] Ethernet cards parameters
726				This option is obsoleted by the "netdev=" option, which
727				has equivalent usage. See its documentation for details.
728	
729		eurwdt=		[HW,WDT] Eurotech CPU-1220/1410 onboard watchdog.
730				Format: <io>[,<irq>]
731	
732		failslab=
733		fail_page_alloc=
734		fail_make_request=[KNL]
735				General fault injection mechanism.
736				Format: <interval>,<probability>,<space>,<times>
737				See also /Documentation/fault-injection/.
738	
739		fd_mcs=		[HW,SCSI]
740				See header of drivers/scsi/fd_mcs.c.
741	
742		fdomain=	[HW,SCSI]
743				See header of drivers/scsi/fdomain.c.
744	
745		floppy=		[HW]
746				See Documentation/blockdev/floppy.txt.
747	
748		force_pal_cache_flush
749				[IA-64] Avoid check_sal_cache_flush which may hang on
750				buggy SAL_CACHE_FLUSH implementations. Using this
751				parameter will force ia64_sal_cache_flush to call
752				ia64_pal_cache_flush instead of SAL_CACHE_FLUSH.
753	
754		ftrace=[tracer]
755				[ftrace] will set and start the specified tracer
756				as early as possible in order to facilitate early
757				boot debugging.
758	
759		ftrace_dump_on_oops
760				[ftrace] will dump the trace buffers on oops.
761	
762		gamecon.map[2|3]=
763				[HW,JOY] Multisystem joystick and NES/SNES/PSX pad
764				support via parallel port (up to 5 devices per port)
765				Format: <port#>,<pad1>,<pad2>,<pad3>,<pad4>,<pad5>
766				See also Documentation/input/joystick-parport.txt
767	
768		gamma=		[HW,DRM]
769	
770		gart_fix_e820=  [X86_64] disable the fix e820 for K8 GART
771				Format: off | on
772				default: on
773	
774		gdth=		[HW,SCSI]
775				See header of drivers/scsi/gdth.c.
776	
777		gpt		[EFI] Forces disk with valid GPT signature but
778				invalid Protective MBR to be treated as GPT.
779	
780		gvp11=		[HW,SCSI]
781	
782		hashdist=	[KNL,NUMA] Large hashes allocated during boot
783				are distributed across NUMA nodes.  Defaults on
784				for 64bit NUMA, off otherwise.
785				Format: 0 | 1 (for off | on)
786	
787		hcl=		[IA-64] SGI's Hardware Graph compatibility layer
788	
789		hd=		[EIDE] (E)IDE hard drive subsystem geometry
790				Format: <cyl>,<head>,<sect>
791	
792		highmem=nn[KMG]	[KNL,BOOT] forces the highmem zone to have an exact
793				size of <nn>. This works even on boxes that have no
794				highmem otherwise. This also works to reduce highmem
795				size on bigger boxes.
796	
797		highres=	[KNL] Enable/disable high resolution timer mode.
798				Valid parameters: "on", "off"
799				Default: "on"
800	
801		hisax=		[HW,ISDN]
802				See Documentation/isdn/README.HiSax.
803	
804		hlt		[BUGS=ARM,SH]
805	
806		hpet=		[X86-32,HPET] option to control HPET usage
807				Format: { enable (default) | disable | force |
808					verbose }
809				disable: disable HPET and use PIT instead
810				force: allow force enabled of undocumented chips (ICH4,
811					VIA, nVidia)
812				verbose: show contents of HPET registers during setup
813	
814		hugepages=	[HW,X86-32,IA-64] HugeTLB pages to allocate at boot.
815		hugepagesz=	[HW,IA-64,PPC,X86-64] The size of the HugeTLB pages.
816				On x86-64 and powerpc, this option can be specified
817				multiple times interleaved with hugepages= to reserve
818				huge pages of different sizes. Valid pages sizes on
819				x86-64 are 2M (when the CPU supports "pse") and 1G
820				(when the CPU supports the "pdpe1gb" cpuinfo flag)
821				Note that 1GB pages can only be allocated at boot time
822				using hugepages= and not freed afterwards.
823	
824		hvc_iucv=	[S390] Number of z/VM IUCV hypervisor console (HVC)
825				       terminal devices. Valid values: 0..8
826		hvc_iucv_allow=	[S390] Comma-separated list of z/VM user IDs.
827				       If specified, z/VM IUCV HVC accepts connections
828				       from listed z/VM user IDs only.
829	
830		i2c_bus=	[HW] Override the default board specific I2C bus speed
831				     or register an additional I2C bus that is not
832				     registered from board initialization code.
833				     Format:
834				     <bus_id>,<clkrate>
835	
836		i8042.debug	[HW] Toggle i8042 debug mode
837		i8042.direct	[HW] Put keyboard port into non-translated mode
838		i8042.dumbkbd	[HW] Pretend that controller can only read data from
839				     keyboard and cannot control its state
840				     (Don't attempt to blink the leds)
841		i8042.noaux	[HW] Don't check for auxiliary (== mouse) port
842		i8042.nokbd	[HW] Don't check/create keyboard port
843		i8042.noloop	[HW] Disable the AUX Loopback command while probing
844				     for the AUX port
845		i8042.nomux	[HW] Don't check presence of an active multiplexing
846				     controller
847		i8042.nopnp	[HW] Don't use ACPIPnP / PnPBIOS to discover KBD/AUX
848				     controllers
849		i8042.panicblink=
850				[HW] Frequency with which keyboard LEDs should blink
851				     when kernel panics (default is 0.5 sec)
852		i8042.reset	[HW] Reset the controller during init and cleanup
853		i8042.unlock	[HW] Unlock (ignore) the keylock
854	
855		i810=		[HW,DRM]
856	
857		i8k.ignore_dmi	[HW] Continue probing hardware even if DMI data
858				indicates that the driver is running on unsupported
859				hardware.
860		i8k.force	[HW] Activate i8k driver even if SMM BIOS signature
861				does not match list of supported models.
862		i8k.power_status
863				[HW] Report power status in /proc/i8k
864				(disabled by default)
865		i8k.restricted	[HW] Allow controlling fans only if SYS_ADMIN
866				capability is set.
867	
868		ibmmcascsi=	[HW,MCA,SCSI] IBM MicroChannel SCSI adapter
869				See Documentation/mca.txt.
870	
871		icn=		[HW,ISDN]
872				Format: <io>[,<membase>[,<icn_id>[,<icn_id2>]]]
873	
874		ide-core.nodma=	[HW] (E)IDE subsystem
875				Format: =0.0 to prevent dma on hda, =0.1 hdb =1.0 hdc
876				.vlb_clock .pci_clock .noflush .noprobe .nowerr .cdrom
877				.chs .ignore_cable are additional options
878				See Documentation/ide/ide.txt.
879	
880		idebus=		[HW] (E)IDE subsystem - VLB/PCI bus speed
881				See Documentation/ide/ide.txt.
882	
883		ide-pci-generic.all-generic-ide [HW] (E)IDE subsystem
884				Claim all unknown PCI IDE storage controllers.
885	
886		idle=		[X86]
887				Format: idle=poll, idle=mwait, idle=halt, idle=nomwait
888				Poll forces a polling idle loop that can slightly
889				improve the performance of waking up a idle CPU, but
890				will use a lot of power and make the system run hot.
891				Not recommended.
892				idle=mwait: On systems which support MONITOR/MWAIT but
893				the kernel chose to not use it because it doesn't save
894				as much power as a normal idle loop, use the
895				MONITOR/MWAIT idle loop anyways. Performance should be
896				the same as idle=poll.
897				idle=halt: Halt is forced to be used for CPU idle.
898				In such case C2/C3 won't be used again.
899				idle=nomwait: Disable mwait for CPU C-states
900	
901		ignore_loglevel	[KNL]
902				Ignore loglevel setting - this will print /all/
903				kernel messages to the console. Useful for debugging.
904	
905		ihash_entries=	[KNL]
906				Set number of hash buckets for inode cache.
907	
908		ima_audit=	[IMA]
909				Format: { "0" | "1" }
910				0 -- integrity auditing messages. (Default)
911				1 -- enable informational integrity auditing messages.
912	
913		ima_hash=	[IMA]
914				Formt: { "sha1" | "md5" }
915				default: "sha1"
916	
917		in2000=		[HW,SCSI]
918				See header of drivers/scsi/in2000.c.
919	
920		init=		[KNL]
921				Format: <full_path>
922				Run specified binary instead of /sbin/init as init
923				process.
924	
925		initcall_debug	[KNL] Trace initcalls as they are executed.  Useful
926				for working out where the kernel is dying during
927				startup.
928	
929		initrd=		[BOOT] Specify the location of the initial ramdisk
930	
931		inport.irq=	[HW] Inport (ATI XL and Microsoft) busmouse driver
932				Format: <irq>
933	
934		intel_iommu=	[DMAR] Intel IOMMU driver (DMAR) option
935			on
936				Enable intel iommu driver.
937			off
938				Disable intel iommu driver.
939			igfx_off [Default Off]
940				By default, gfx is mapped as normal device. If a gfx
941				device has a dedicated DMAR unit, the DMAR unit is
942				bypassed by not enabling DMAR with this option. In
943				this case, gfx device will use physical address for
944				DMA.
945			forcedac [x86_64]
946				With this option iommu will not optimize to look
947				for io virtual address below 32 bit forcing dual
948				address cycle on pci bus for cards supporting greater
949				than 32 bit addressing. The default is to look
950				for translation below 32 bit and if not available
951				then look in the higher range.
952			strict [Default Off]
953				With this option on every unmap_single operation will
954				result in a hardware IOTLB flush operation as opposed
955				to batching them for performance.
956	
957		inttest=	[IA64]
958	
959		iomem=		Disable strict checking of access to MMIO memory
960			strict	regions from userspace.
961			relaxed
962	
963		iommu=		[x86]
964			off
965			force
966			noforce
967			biomerge
968			panic
969			nopanic
970			merge
971			nomerge
972			forcesac
973			soft
974	
975		io7=		[HW] IO7 for Marvel based alpha systems
976				See comment before marvel_specify_io7 in
977				arch/alpha/kernel/core_marvel.c.
978	
979		io_delay=	[X86] I/O delay method
980			0x80
981				Standard port 0x80 based delay
982			0xed
983				Alternate port 0xed based delay (needed on some systems)
984			udelay
985				Simple two microseconds delay
986			none
987				No delay
988	
989		ip=		[IP_PNP]
990				See Documentation/filesystems/nfsroot.txt.
991	
992		ip2=		[HW] Set IO/IRQ pairs for up to 4 IntelliPort boards
993				See comment before ip2_setup() in
994				drivers/char/ip2/ip2base.c.
995	
996		ips=		[HW,SCSI] Adaptec / IBM ServeRAID controller
997				See header of drivers/scsi/ips.c.
998	
999		irqfixup	[HW]
1000				When an interrupt is not handled search all handlers
1001				for it. Intended to get systems with badly broken
1002				firmware running.
1003	
1004		irqpoll		[HW]
1005				When an interrupt is not handled search all handlers
1006				for it. Also check all handlers each timer
1007				interrupt. Intended to get systems with badly broken
1008				firmware running.
1009	
1010		isapnp=		[ISAPNP]
1011				Format: <RDP>,<reset>,<pci_scan>,<verbosity>
1012	
1013		isolcpus=	[KNL,SMP] Isolate CPUs from the general scheduler.
1014				Format:
1015				<cpu number>,...,<cpu number>
1016				or
1017				<cpu number>-<cpu number>
1018				(must be a positive range in ascending order)
1019				or a mixture
1020				<cpu number>,...,<cpu number>-<cpu number>
1021	
1022				This option can be used to specify one or more CPUs
1023				to isolate from the general SMP balancing and scheduling
1024				algorithms. You can move a process onto or off an
1025				"isolated" CPU via the CPU affinity syscalls or cpuset.
1026				<cpu number> begins at 0 and the maximum value is
1027				"number of CPUs in system - 1".
1028	
1029				This option is the preferred way to isolate CPUs. The
1030				alternative -- manually setting the CPU mask of all
1031				tasks in the system -- can cause problems and
1032				suboptimal load balancer performance.
1033	
1034		iucv=		[HW,NET]
1035	
1036		js=		[HW,JOY] Analog joystick
1037				See Documentation/input/joystick.txt.
1038	
1039		keepinitrd	[HW,ARM]
1040	
1041		kernelcore=nn[KMG]	[KNL,X86,IA-64,PPC] This parameter
1042				specifies the amount of memory usable by the kernel
1043				for non-movable allocations.  The requested amount is
1044				spread evenly throughout all nodes in the system. The
1045				remaining memory in each node is used for Movable
1046				pages. In the event, a node is too small to have both
1047				kernelcore and Movable pages, kernelcore pages will
1048				take priority and other nodes will have a larger number
1049				of kernelcore pages.  The Movable zone is used for the
1050				allocation of pages that may be reclaimed or moved
1051				by the page migration subsystem.  This means that
1052				HugeTLB pages may not be allocated from this zone.
1053				Note that allocations like PTEs-from-HighMem still
1054				use the HighMem zone if it exists, and the Normal
1055				zone if it does not.
1056	
1057		kmemtrace.enable=	[KNL,KMEMTRACE] Format: { yes | no }
1058					Controls whether kmemtrace is enabled
1059					at boot-time.
1060	
1061		kmemtrace.subbufs=n	[KNL,KMEMTRACE] Overrides the number of
1062				subbufs kmemtrace's relay channel has. Set this
1063				higher than default (KMEMTRACE_N_SUBBUFS in code) if
1064				you experience buffer overruns.
1065	
1066		kgdboc=		[HW] kgdb over consoles.
1067				Requires a tty driver that supports console polling.
1068				(only serial suported for now)
1069				Format: <serial_device>[,baud]
1070	
1071		kmac=		[MIPS] korina ethernet MAC address.
1072				Configure the RouterBoard 532 series on-chip
1073				Ethernet adapter MAC address.
1074	
1075		kstack=N	[X86] Print N words from the kernel stack
1076				in oops dumps.
1077	
1078		l2cr=		[PPC]
1079	
1080		l3cr=		[PPC]
1081	
1082		lapic		[X86-32,APIC] Enable the local APIC even if BIOS
1083				disabled it.
1084	
1085		lapic_timer_c2_ok	[X86,APIC] trust the local apic timer
1086				in C2 power state.
1087	
1088		libata.dma=	[LIBATA] DMA control
1089				libata.dma=0	  Disable all PATA and SATA DMA
1090				libata.dma=1	  PATA and SATA Disk DMA only
1091				libata.dma=2	  ATAPI (CDROM) DMA only
1092				libata.dma=4	  Compact Flash DMA only 
1093				Combinations also work, so libata.dma=3 enables DMA
1094				for disks and CDROMs, but not CFs.
1095	
1096		libata.noacpi	[LIBATA] Disables use of ACPI in libata suspend/resume
1097				when set.
1098				Format: <int>
1099	
1100		libata.force=	[LIBATA] Force configurations.  The format is comma
1101				separated list of "[ID:]VAL" where ID is
1102				PORT[:DEVICE].  PORT and DEVICE are decimal numbers
1103				matching port, link or device.  Basically, it matches
1104				the ATA ID string printed on console by libata.  If
1105				the whole ID part is omitted, the last PORT and DEVICE
1106				values are used.  If ID hasn't been specified yet, the
1107				configuration applies to all ports, links and devices.
1108	
1109				If only DEVICE is omitted, the parameter applies to
1110				the port and all links and devices behind it.  DEVICE
1111				number of 0 either selects the first device or the
1112				first fan-out link behind PMP device.  It does not
1113				select the host link.  DEVICE number of 15 selects the
1114				host link and device attached to it.
1115	
1116				The VAL specifies the configuration to force.  As long
1117				as there's no ambiguity shortcut notation is allowed.
1118				For example, both 1.5 and 1.5G would work for 1.5Gbps.
1119				The following configurations can be forced.
1120	
1121				* Cable type: 40c, 80c, short40c, unk, ign or sata.
1122				  Any ID with matching PORT is used.
1123	
1124				* SATA link speed limit: 1.5Gbps or 3.0Gbps.
1125	
1126				* Transfer mode: pio[0-7], mwdma[0-4] and udma[0-7].
1127				  udma[/][16,25,33,44,66,100,133] notation is also
1128				  allowed.
1129	
1130				* [no]ncq: Turn on or off NCQ.
1131	
1132				* nohrst, nosrst, norst: suppress hard, soft
1133	                          and both resets.
1134	
1135				If there are multiple matching configurations changing
1136				the same attribute, the last one is used.
1137	
1138		lmb=debug	[KNL] Enable lmb debug messages.
1139	
1140		load_ramdisk=	[RAM] List of ramdisks to load from floppy
1141				See Documentation/blockdev/ramdisk.txt.
1142	
1143		lockd.nlm_grace_period=P  [NFS] Assign grace period.
1144				Format: <integer>
1145	
1146		lockd.nlm_tcpport=N	[NFS] Assign TCP port.
1147				Format: <integer>
1148	
1149		lockd.nlm_timeout=T	[NFS] Assign timeout value.
1150				Format: <integer>
1151	
1152		lockd.nlm_udpport=M	[NFS] Assign UDP port.
1153				Format: <integer>
1154	
1155		logibm.irq=	[HW,MOUSE] Logitech Bus Mouse Driver
1156				Format: <irq>
1157	
1158		loglevel=	All Kernel Messages with a loglevel smaller than the
1159				console loglevel will be printed to the console. It can
1160				also be changed with klogd or other programs. The
1161				loglevels are defined as follows:
1162	
1163				0 (KERN_EMERG)		system is unusable
1164				1 (KERN_ALERT)		action must be taken immediately
1165				2 (KERN_CRIT)		critical conditions
1166				3 (KERN_ERR)		error conditions
1167				4 (KERN_WARNING)	warning conditions
1168				5 (KERN_NOTICE)		normal but significant condition
1169				6 (KERN_INFO)		informational
1170				7 (KERN_DEBUG)		debug-level messages
1171	
1172		log_buf_len=n	Sets the size of the printk ring buffer, in bytes.
1173				Format: { n | nk | nM }
1174				n must be a power of two.  The default size
1175				is set in the kernel config file.
1176	
1177		logo.nologo	[FB] Disables display of the built-in Linux logo.
1178				This may be used to provide more screen space for
1179				kernel log messages and is useful when debugging
1180				kernel boot problems.
1181	
1182		lp=0		[LP]	Specify parallel ports to use, e.g,
1183		lp=port[,port...]	lp=none,parport0 (lp0 not configured, lp1 uses
1184		lp=reset		first parallel port). 'lp=0' disables the
1185		lp=auto			printer driver. 'lp=reset' (which can be
1186					specified in addition to the ports) causes
1187					attached printers to be reset. Using
1188					lp=port1,port2,... specifies the parallel ports
1189					to associate lp devices with, starting with
1190					lp0. A port specification may be 'none' to skip
1191					that lp device, or a parport name such as
1192					'parport0'. Specifying 'lp=auto' instead of a
1193					port specification list means that device IDs
1194					from each port should be examined, to see if
1195					an IEEE 1284-compliant printer is attached; if
1196					so, the driver will manage that printer.
1197					See also header of drivers/char/lp.c.
1198	
1199		lpj=n		[KNL]
1200				Sets loops_per_jiffy to given constant, thus avoiding
1201				time-consuming boot-time autodetection (up to 250 ms per
1202				CPU). 0 enables autodetection (default). To determine
1203				the correct value for your kernel, boot with normal
1204				autodetection and see what value is printed. Note that
1205				on SMP systems the preset will be applied to all CPUs,
1206				which is likely to cause problems if your CPUs need
1207				significantly divergent settings. An incorrect value
1208				will cause delays in the kernel to be wrong, leading to
1209				unpredictable I/O errors and other breakage. Although
1210				unlikely, in the extreme case this might damage your
1211				hardware.
1212	
1213		ltpc=		[NET]
1214				Format: <io>,<irq>,<dma>
1215	
1216		mac5380=	[HW,SCSI] Format:
1217				<can_queue>,<cmd_per_lun>,<sg_tablesize>,<hostid>,<use_tags>
1218	
1219		machvec=	[IA64] Force the use of a particular machine-vector
1220				(machvec) in a generic kernel.
1221				Example: machvec=hpzx1_swiotlb
1222	
1223		max_addr=nn[KMG]	[KNL,BOOT,ia64] All physical memory greater
1224				than or equal to this physical address is ignored.
1225	
1226		maxcpus=	[SMP] Maximum number of processors that	an SMP kernel
1227				should make use of.  maxcpus=n : n >= 0 limits the
1228				kernel to using 'n' processors.  n=0 is a special case,
1229				it is equivalent to "nosmp", which also disables
1230				the IO APIC.
1231	
1232		max_loop=	[LOOP] Maximum number of loopback devices that can
1233				be mounted
1234				Format: <1-256>
1235	
1236		max_luns=	[SCSI] Maximum number of LUNs to probe.
1237				Should be between 1 and 2^32-1.
1238	
1239		max_report_luns=
1240				[SCSI] Maximum number of LUNs received.
1241				Should be between 1 and 16384.
1242	
1243		mcatest=	[IA-64]
1244	
1245		mce		[X86-32] Machine Check Exception
1246	
1247		mce=option	[X86-64] See Documentation/x86/x86_64/boot-options.txt
1248	
1249		md=		[HW] RAID subsystems devices and level
1250				See Documentation/md.txt.
1251	
1252		mdacon=		[MDA]
1253				Format: <first>,<last>
1254				Specifies range of consoles to be captured by the MDA.
1255	
1256		mem=nn[KMG]	[KNL,BOOT] Force usage of a specific amount of memory
1257				Amount of memory to be used when the kernel is not able
1258				to see the whole system memory or for test.
1259				[X86-32] Use together with memmap= to avoid physical
1260				address space collisions. Without memmap= PCI devices
1261				could be placed at addresses belonging to unused RAM.
1262	
1263		mem=nopentium	[BUGS=X86-32] Disable usage of 4MB pages for kernel
1264				memory.
1265	
1266		memchunk=nn[KMG]
1267				[KNL,SH] Allow user to override the default size for
1268				per-device physically contiguous DMA buffers.
1269	
1270		memmap=exactmap	[KNL,X86] Enable setting of an exact
1271				E820 memory map, as specified by the user.
1272				Such memmap=exactmap lines can be constructed based on
1273				BIOS output or other requirements. See the memmap=nn@ss
1274				option description.
1275	
1276		memmap=nn[KMG]@ss[KMG]
1277				[KNL] Force usage of a specific region of memory
1278				Region of memory to be used, from ss to ss+nn.
1279	
1280		memmap=nn[KMG]#ss[KMG]
1281				[KNL,ACPI] Mark specific memory as ACPI data.
1282				Region of memory to be used, from ss to ss+nn.
1283	
1284		memmap=nn[KMG]$ss[KMG]
1285				[KNL,ACPI] Mark specific memory as reserved.
1286				Region of memory to be used, from ss to ss+nn.
1287				Example: Exclude memory from 0x18690000-0x1869ffff
1288				         memmap=64K$0x18690000
1289				         or
1290				         memmap=0x10000$0x18690000
1291	
1292		memory_corruption_check=0/1 [X86]
1293				Some BIOSes seem to corrupt the first 64k of
1294				memory when doing things like suspend/resume.
1295				Setting this option will scan the memory
1296				looking for corruption.  Enabling this will
1297				both detect corruption and prevent the kernel
1298				from using the memory being corrupted.
1299				However, its intended as a diagnostic tool; if
1300				repeatable BIOS-originated corruption always
1301				affects the same memory, you can use memmap=
1302				to prevent the kernel from using that memory.
1303	
1304		memory_corruption_check_size=size [X86]
1305				By default it checks for corruption in the low
1306				64k, making this memory unavailable for normal
1307				use.  Use this parameter to scan for
1308				corruption in more or less memory.
1309	
1310		memory_corruption_check_period=seconds [X86]
1311				By default it checks for corruption every 60
1312				seconds.  Use this parameter to check at some
1313				other rate.  0 disables periodic checking.
1314	
1315		memtest=	[KNL,X86] Enable memtest
1316				Format: <integer>
1317				default : 0 <disable>
1318				Specifies the number of memtest passes to be
1319				performed. Each pass selects another test
1320				pattern from a given set of patterns. Memtest
1321				fills the memory with this pattern, validates
1322				memory contents and reserves bad memory
1323				regions that are detected.
1324	
1325		meye.*=		[HW] Set MotionEye Camera parameters
1326				See Documentation/video4linux/meye.txt.
1327	
1328		mfgpt_irq=	[IA-32] Specify the IRQ to use for the
1329				Multi-Function General Purpose Timers on AMD Geode
1330				platforms.
1331	
1332		mfgptfix	[X86-32] Fix MFGPT timers on AMD Geode platforms when
1333				the BIOS has incorrectly applied a workaround. TinyBIOS
1334				version 0.98 is known to be affected, 0.99 fixes the
1335				problem by letting the user disable the workaround.
1336	
1337		mga=		[HW,DRM]
1338	
1339		min_addr=nn[KMG]	[KNL,BOOT,ia64] All physical memory below this
1340				physical address is ignored.
1341	
1342		mminit_loglevel=
1343				[KNL] When CONFIG_DEBUG_MEMORY_INIT is set, this
1344				parameter allows control of the logging verbosity for
1345				the additional memory initialisation checks. A value
1346				of 0 disables mminit logging and a level of 4 will
1347				log everything. Information is printed at KERN_DEBUG
1348				so loglevel=8 may also need to be specified.
1349	
1350		mousedev.tap_time=
1351				[MOUSE] Maximum time between finger touching and
1352				leaving touchpad surface for touch to be considered
1353				a tap and be reported as a left button click (for
1354				touchpads working in absolute mode only).
1355				Format: <msecs>
1356		mousedev.xres=	[MOUSE] Horizontal screen resolution, used for devices
1357				reporting absolute coordinates, such as tablets
1358		mousedev.yres=	[MOUSE] Vertical screen resolution, used for devices
1359				reporting absolute coordinates, such as tablets
1360	
1361		movablecore=nn[KMG]	[KNL,X86,IA-64,PPC] This parameter
1362				is similar to kernelcore except it specifies the
1363				amount of memory used for migratable allocations.
1364				If both kernelcore and movablecore is specified,
1365				then kernelcore will be at *least* the specified
1366				value but may be more. If movablecore on its own
1367				is specified, the administrator must be careful
1368				that the amount of memory usable for all allocations
1369				is not too small.
1370	
1371		mpu401=		[HW,OSS]
1372				Format: <io>,<irq>
1373	
1374		MTD_Partition=	[MTD]
1375				Format: <name>,<region-number>,<size>,<offset>
1376	
1377		MTD_Region=	[MTD] Format:
1378				<name>,<region-number>[,<base>,<size>,<buswidth>,<altbuswidth>]
1379	
1380		mtdparts=	[MTD]
1381				See drivers/mtd/cmdlinepart.c.
1382	
1383		mtdset=		[ARM]
1384				ARM/S3C2412 JIVE boot control
1385	
1386				See arch/arm/mach-s3c2412/mach-jive.c
1387	
1388		mtouchusb.raw_coordinates=
1389				[HW] Make the MicroTouch USB driver use raw coordinates
1390				('y', default) or cooked coordinates ('n')
1391	
1392		mtrr_chunk_size=nn[KMG] [X86]
1393				used for mtrr cleanup. It is largest continous chunk
1394				that could hold holes aka. UC entries.
1395	
1396		mtrr_gran_size=nn[KMG] [X86]
1397				Used for mtrr cleanup. It is granularity of mtrr block.
1398				Default is 1.
1399				Large value could prevent small alignment from
1400				using up MTRRs.
1401	
1402		mtrr_spare_reg_nr=n [X86]
1403				Format: <integer>
1404				Range: 0,7 : spare reg number
1405				Default : 1
1406				Used for mtrr cleanup. It is spare mtrr entries number.
1407				Set to 2 or more if your graphical card needs more.
1408	
1409		n2=		[NET] SDL Inc. RISCom/N2 synchronous serial card
1410	
1411		NCR_D700=	[HW,SCSI]
1412				See header of drivers/scsi/NCR_D700.c.
1413	
1414		ncr5380=	[HW,SCSI]
1415	
1416		ncr53c400=	[HW,SCSI]
1417	
1418		ncr53c400a=	[HW,SCSI]
1419	
1420		ncr53c406a=	[HW,SCSI]
1421	
1422		ncr53c8xx=	[HW,SCSI]
1423	
1424		netdev=		[NET] Network devices parameters
1425				Format: <irq>,<io>,<mem_start>,<mem_end>,<name>
1426				Note that mem_start is often overloaded to mean
1427				something different and driver-specific.
1428				This usage is only documented in each driver source
1429				file if at all.
1430	
1431		nf_conntrack.acct=
1432				[NETFILTER] Enable connection tracking flow accounting
1433				0 to disable accounting
1434				1 to enable accounting
1435				Default value depends on CONFIG_NF_CT_ACCT that is
1436				going to be removed in 2.6.29.
1437	
1438		nfsaddrs=	[NFS]
1439				See Documentation/filesystems/nfsroot.txt.
1440	
1441		nfsroot=	[NFS] nfs root filesystem for disk-less boxes.
1442				See Documentation/filesystems/nfsroot.txt.
1443	
1444		nfs.callback_tcpport=
1445				[NFS] set the TCP port on which the NFSv4 callback
1446				channel should listen.
1447	
1448		nfs.idmap_cache_timeout=
1449				[NFS] set the maximum lifetime for idmapper cache
1450				entries.
1451	
1452		nfs.enable_ino64=
1453				[NFS] enable 64-bit inode numbers.
1454				If zero, the NFS client will fake up a 32-bit inode
1455				number for the readdir() and stat() syscalls instead
1456				of returning the full 64-bit number.
1457				The default is to return 64-bit inode numbers.
1458	
1459		nmi_debug=	[KNL,AVR32] Specify one or more actions to take
1460				when a NMI is triggered.
1461				Format: [state][,regs][,debounce][,die]
1462	
1463		nmi_watchdog=	[KNL,BUGS=X86] Debugging features for SMP kernels
1464				Format: [panic,][num]
1465				Valid num: 0,1,2
1466				0 - turn nmi_watchdog off
1467				1 - use the IO-APIC timer for the NMI watchdog
1468				2 - use the local APIC for the NMI watchdog using
1469				a performance counter. Note: This will use one
1470				performance counter and the local APIC's performance
1471				vector.
1472				When panic is specified, panic when an NMI watchdog
1473				timeout occurs.
1474				This is useful when you use a panic=... timeout and
1475				need the box quickly up again.
1476				Instead of 1 and 2 it is possible to use the following
1477				symbolic names: lapic and ioapic
1478				Example: nmi_watchdog=2 or nmi_watchdog=panic,lapic
1479	
1480		no387		[BUGS=X86-32] Tells the kernel to use the 387 maths
1481				emulation library even if a 387 maths coprocessor
1482				is present.
1483	
1484		no_console_suspend
1485				[HW] Never suspend the console
1486				Disable suspending of consoles during suspend and
1487				hibernate operations.  Once disabled, debugging
1488				messages can reach various consoles while the rest
1489				of the system is being put to sleep (ie, while
1490				debugging driver suspend/resume hooks).  This may
1491				not work reliably with all consoles, but is known
1492				to work with serial and VGA consoles.
1493	
1494		noaliencache	[MM, NUMA, SLAB] Disables the allocation of alien
1495				caches in the slab allocator.  Saves per-node memory,
1496				but will impact performance.
1497	
1498		noalign		[KNL,ARM]
1499	
1500		noapic		[SMP,APIC] Tells the kernel to not make use of any
1501				IOAPICs that may be present in the system.
1502	
1503		nobats		[PPC] Do not use BATs for mapping kernel lowmem
1504				on "Classic" PPC cores.
1505	
1506		nocache		[ARM]
1507	
1508		noclflush	[BUGS=X86] Don't use the CLFLUSH instruction
1509	
1510		nodelayacct	[KNL] Disable per-task delay accounting
1511	
1512		nodisconnect	[HW,SCSI,M68K] Disables SCSI disconnects.
1513	
1514		nodsp		[SH] Disable hardware DSP at boot time.
1515	
1516		noefi		[X86] Disable EFI runtime services support.
1517	
1518		noexec		[IA-64]
1519	
1520		noexec		[X86]
1521				On X86-32 available only on PAE configured kernels.
1522				noexec=on: enable non-executable mappings (default)
1523				noexec=off: disable non-executable mappings
1524	
1525		noexec32	[X86-64]
1526				This affects only 32-bit executables.
1527				noexec32=on: enable non-executable mappings (default)
1528					read doesn't imply executable mappings
1529				noexec32=off: disable non-executable mappings
1530					read implies executable mappings
1531	
1532		nofpu		[SH] Disable hardware FPU at boot time.
1533	
1534		nofxsr		[BUGS=X86-32] Disables x86 floating point extended
1535				register save and restore. The kernel will only save
1536				legacy floating-point registers on task switch.
1537	
1538		noxsave		[BUGS=X86] Disables x86 extended register state save
1539				and restore using xsave. The kernel will fallback to
1540				enabling legacy floating-point and sse state.
1541	
1542		nohlt		[BUGS=ARM,SH] Tells the kernel that the sleep(SH) or
1543				wfi(ARM) instruction doesn't work correctly and not to
1544				use it. This is also useful when using JTAG debugger.
1545	
1546		no-hlt		[BUGS=X86-32] Tells the kernel that the hlt
1547				instruction doesn't work correctly and not to
1548				use it.
1549	
1550		no_file_caps	Tells the kernel not to honor file capabilities.  The
1551				only way then for a file to be executed with privilege
1552				is to be setuid root or executed by root.
1553	
1554		nohalt		[IA-64] Tells the kernel not to use the power saving
1555				function PAL_HALT_LIGHT when idle. This increases
1556				power-consumption. On the positive side, it reduces
1557				interrupt wake-up latency, which may improve performance
1558				in certain environments such as networked servers or
1559				real-time systems.
1560	
1561		nohz=		[KNL] Boottime enable/disable dynamic ticks
1562				Valid arguments: on, off
1563				Default: on
1564	
1565		noiotrap	[SH] Disables trapped I/O port accesses.
1566	
1567		noirqdebug	[X86-32] Disables the code which attempts to detect and
1568				disable unhandled interrupt sources.
1569	
1570		no_timer_check	[X86,APIC] Disables the code which tests for
1571				broken timer IRQ sources.
1572	
1573		noisapnp	[ISAPNP] Disables ISA PnP code.
1574	
1575		noinitrd	[RAM] Tells the kernel not to load any configured
1576				initial RAM disk.
1577	
1578		nointroute	[IA-64]
1579	
1580		nojitter	[IA64] Disables jitter checking for ITC timers.
1581	
1582		nolapic		[X86-32,APIC] Do not enable or use the local APIC.
1583	
1584		nolapic_timer	[X86-32,APIC] Do not use the local APIC timer.
1585	
1586		noltlbs		[PPC] Do not use large page/tlb entries for kernel
1587				lowmem mapping on PPC40x.
1588	
1589		nomca		[IA-64] Disable machine check abort handling
1590	
1591		nomce		[X86-32] Machine Check Exception
1592	
1593		nomfgpt		[X86-32] Disable Multi-Function General Purpose
1594				Timer usage (for AMD Geode machines).
1595	
1596		norandmaps	Don't use address space randomization.  Equivalent to
1597				echo 0 > /proc/sys/kernel/randomize_va_space
1598	
1599		noreplace-paravirt	[X86-32,PV_OPS] Don't patch paravirt_ops
1600	
1601		noreplace-smp	[X86-32,SMP] Don't replace SMP instructions
1602				with UP alternatives
1603	
1604		noresidual	[PPC] Don't use residual data on PReP machines.
1605	
1606		noresume	[SWSUSP] Disables resume and restores original swap
1607				space.
1608	
1609		no-scroll	[VGA] Disables scrollback.
1610				This is required for the Braillex ib80-piezo Braille
1611				reader made by F.H. Papenmeier (Germany).
1612	
1613		nosbagart	[IA-64]
1614	
1615		nosep		[BUGS=X86-32] Disables x86 SYSENTER/SYSEXIT support.
1616	
1617		nosmp		[SMP] Tells an SMP kernel to act as a UP kernel,
1618				and disable the IO APIC.  legacy for "maxcpus=0".
1619	
1620		nosoftlockup	[KNL] Disable the soft-lockup detector.
1621	
1622		noswapaccount	[KNL] Disable accounting of swap in memory resource
1623				controller. (See Documentation/cgroups/memory.txt)
1624	
1625		nosync		[HW,M68K] Disables sync negotiation for all devices.
1626	
1627		notsc		[BUGS=X86-32] Disable Time Stamp Counter
1628	
1629		nousb		[USB] Disable the USB subsystem
1630	
1631		nowb		[ARM]
1632	
1633		nox2apic	[X86-64,APIC] Do not enable x2APIC mode.
1634	
1635		nptcg=		[IA64] Override max number of concurrent global TLB
1636				purges which is reported from either PAL_VM_SUMMARY or
1637				SAL PALO.
1638	
1639		nr_uarts=	[SERIAL] maximum number of UARTs to be registered.
1640	
1641		numa_zonelist_order= [KNL, BOOT] Select zonelist order for NUMA.
1642				one of ['zone', 'node', 'default'] can be specified
1643				This can be set from sysctl after boot.
1644				See Documentation/sysctl/vm.txt for details.
1645	
1646		ohci1394_dma=early	[HW] enable debugging via the ohci1394 driver.
1647				See Documentation/debugging-via-ohci1394.txt for more
1648				info.
1649	
1650		olpc_ec_timeout= [OLPC] ms delay when issuing EC commands
1651				Rather than timing out after 20 ms if an EC
1652				command is not properly ACKed, override the length
1653				of the timeout.  We have interrupts disabled while
1654				waiting for the ACK, so if this is set too high
1655				interrupts *may* be lost!
1656	
1657		opl3=		[HW,OSS]
1658				Format: <io>
1659	
1660		oprofile.timer=	[HW]
1661				Use timer interrupt instead of performance counters
1662	
1663		osst=		[HW,SCSI] SCSI Tape Driver
1664				Format: <buffer_size>,<write_threshold>
1665				See also Documentation/scsi/st.txt.
1666	
1667		panic=		[KNL] Kernel behaviour on panic
1668				Format: <timeout>
1669	
1670		parkbd.port=	[HW] Parallel port number the keyboard adapter is
1671				connected to, default is 0.
1672				Format: <parport#>
1673		parkbd.mode=	[HW] Parallel port keyboard adapter mode of operation,
1674				0 for XT, 1 for AT (default is AT).
1675				Format: <mode>
1676	
1677		parport=	[HW,PPT] Specify parallel ports. 0 disables.
1678				Format: { 0 | auto | 0xBBB[,IRQ[,DMA]] }
1679				Use 'auto' to force the driver to use any
1680				IRQ/DMA settings detected (the default is to
1681				ignore detected IRQ/DMA settings because of
1682				possible conflicts). You can specify the base
1683				address, IRQ, and DMA settings; IRQ and DMA
1684				should be numbers, or 'auto' (for using detected
1685				settings on that particular port), or 'nofifo'
1686				(to avoid using a FIFO even if it is detected).
1687				Parallel ports are assigned in the order they
1688				are specified on the command line, starting
1689				with parport0.
1690	
1691		parport_init_mode=	[HW,PPT]
1692				Configure VIA parallel port to operate in
1693				a specific mode. This is necessary on Pegasos
1694				computer where firmware has no options for setting
1695				up parallel port mode and sets it to spp.
1696				Currently this function knows 686a and 8231 chips.
1697				Format: [spp|ps2|epp|ecp|ecpepp]
1698	
1699		pas2=		[HW,OSS] Format:
1700				<io>,<irq>,<dma>,<dma16>,<sb_io>,<sb_irq>,<sb_dma>,<sb_dma16>
1701	
1702		pas16=		[HW,SCSI]
1703				See header of drivers/scsi/pas16.c.
1704	
1705		pause_on_oops=
1706				Halt all CPUs after the first oops has been printed for
1707				the specified number of seconds.  This is to be used if
1708				your oopses keep scrolling off the screen.
1709	
1710		pcbit=		[HW,ISDN]
1711	
1712		pcd.		[PARIDE]
1713				See header of drivers/block/paride/pcd.c.
1714				See also Documentation/blockdev/paride.txt.
1715	
1716		pci=option[,option...]	[PCI] various PCI subsystem options:
1717			earlydump	[X86] dump PCI config space before the kernel
1718				        changes anything
1719			off		[X86] don't probe for the PCI bus
1720			bios		[X86-32] force use of PCI BIOS, don't access
1721					the hardware directly. Use this if your machine
1722					has a non-standard PCI host bridge.
1723			nobios		[X86-32] disallow use of PCI BIOS, only direct
1724					hardware access methods are allowed. Use this
1725					if you experience crashes upon bootup and you
1726					suspect they are caused by the BIOS.
1727			conf1		[X86] Force use of PCI Configuration
1728					Mechanism 1.
1729			conf2		[X86] Force use of PCI Configuration
1730					Mechanism 2.
1731			noaer		[PCIE] If the PCIEAER kernel config parameter is
1732					enabled, this kernel boot option can be used to
1733					disable the use of PCIE advanced error reporting.
1734			nodomains	[PCI] Disable support for multiple PCI
1735					root domains (aka PCI segments, in ACPI-speak).
1736			nommconf	[X86] Disable use of MMCONFIG for PCI
1737					Configuration
1738			nomsi		[MSI] If the PCI_MSI kernel config parameter is
1739					enabled, this kernel boot option can be used to
1740					disable the use of MSI interrupts system-wide.
1741			noioapicquirk	[APIC] Disable all boot interrupt quirks.
1742					Safety option to keep boot IRQs enabled. This
1743					should never be necessary.
1744			ioapicreroute	[APIC] Enable rerouting of boot IRQs to the
1745					primary IO-APIC for bridges that cannot disable
1746					boot IRQs. This fixes a source of spurious IRQs
1747					when the system masks IRQs.
1748			noioapicreroute	[APIC] Disable workaround that uses the
1749					boot IRQ equivalent of an IRQ that connects to
1750					a chipset where boot IRQs cannot be disabled.
1751					The opposite of ioapicreroute.
1752			biosirq		[X86-32] Use PCI BIOS calls to get the interrupt
1753					routing table. These calls are known to be buggy
1754					on several machines and they hang the machine
1755					when used, but on other computers it's the only
1756					way to get the interrupt routing table. Try
1757					this option if the kernel is unable to allocate
1758					IRQs or discover secondary PCI buses on your
1759					motherboard.
1760			rom		[X86] Assign address space to expansion ROMs.
1761					Use with caution as certain devices share
1762					address decoders between ROMs and other
1763					resources.
1764			norom		[X86] Do not assign address space to
1765					expansion ROMs that do not already have
1766					BIOS assigned address ranges.
1767			irqmask=0xMMMM	[X86] Set a bit mask of IRQs allowed to be
1768					assigned automatically to PCI devices. You can
1769					make the kernel exclude IRQs of your ISA cards
1770					this way.
1771			pirqaddr=0xAAAAA	[X86] Specify the physical address
1772					of the PIRQ table (normally generated
1773					by the BIOS) if it is outside the
1774					F0000h-100000h range.
1775			lastbus=N	[X86] Scan all buses thru bus #N. Can be
1776					useful if the kernel is unable to find your
1777					secondary buses and you want to tell it
1778					explicitly which ones they are.
1779			assign-busses	[X86] Always assign all PCI bus
1780					numbers ourselves, overriding
1781					whatever the firmware may have done.
1782			usepirqmask	[X86] Honor the possible IRQ mask stored
1783					in the BIOS $PIR table. This is needed on
1784					some systems with broken BIOSes, notably
1785					some HP Pavilion N5400 and Omnibook XE3
1786					notebooks. This will have no effect if ACPI
1787					IRQ routing is enabled.
1788			noacpi		[X86] Do not use ACPI for IRQ routing
1789					or for PCI scanning.
1790			use_crs		[X86] Use _CRS for PCI resource
1791					allocation.
1792			routeirq	Do IRQ routing for all PCI devices.
1793					This is normally done in pci_enable_device(),
1794					so this option is a temporary workaround
1795					for broken drivers that don't call it.
1796			skip_isa_align	[X86] do not align io start addr, so can
1797					handle more pci cards
1798			firmware	[ARM] Do not re-enumerate the bus but instead
1799					just use the configuration from the
1800					bootloader. This is currently used on
1801					IXP2000 systems where the bus has to be
1802					configured a certain way for adjunct CPUs.
1803			noearly		[X86] Don't do any early type 1 scanning.
1804					This might help on some broken boards which
1805					machine check when some devices' config space
1806					is read. But various workarounds are disabled
1807					and some IOMMU drivers will not work.
1808			bfsort		Sort PCI devices into breadth-first order.
1809					This sorting is done to get a device
1810					order compatible with older (<= 2.4) kernels.
1811			nobfsort	Don't sort PCI devices into breadth-first order.
1812			cbiosize=nn[KMG]	The fixed amount of bus space which is
1813					reserved for the CardBus bridge's IO window.
1814					The default value is 256 bytes.
1815			cbmemsize=nn[KMG]	The fixed amount of bus space which is
1816					reserved for the CardBus bridge's memory
1817					window. The default value is 64 megabytes.
1818			resource_alignment=
1819					Format:
1820					[<order of align>[AT]][<domain>:]<bus>:<slot>.<func>[; ..[DOT]]
1821					Specifies alignment and device to reassign
1822					aligned memory resources.
1823					If <order of align> is not specified,
1824					PAGE_SIZE is used as alignment.
1825					PCI-PCI bridge can be specified, if resource
1826					windows need to be expanded.
1827	
1828		pcie_aspm=	[PCIE] Forcibly enable or disable PCIe Active State Power
1829				Management.
1830			off	Disable ASPM.
1831			force	Enable ASPM even on devices that claim not to support it.
1832				WARNING: Forcing ASPM on may cause system lockups.
1833	
1834		pcmv=		[HW,PCMCIA] BadgePAD 4
1835	
1836		pd.		[PARIDE]
1837				See Documentation/blockdev/paride.txt.
1838	
1839		pdcchassis=	[PARISC,HW] Disable/Enable PDC Chassis Status codes at
1840				boot time.
1841				Format: { 0 | 1 }
1842				See arch/parisc/kernel/pdc_chassis.c
1843	
1844		pf.		[PARIDE]
1845				See Documentation/blockdev/paride.txt.
1846	
1847		pg.		[PARIDE]
1848				See Documentation/blockdev/paride.txt.
1849	
1850		pirq=		[SMP,APIC] Manual mp-table setup
1851				See Documentation/x86/i386/IO-APIC.txt.
1852	
1853		plip=		[PPT,NET] Parallel port network link
1854				Format: { parport<nr> | timid | 0 }
1855				See also Documentation/parport.txt.
1856	
1857		pmtmr=		[X86] Manual setup of pmtmr I/O Port. 
1858				Override pmtimer IOPort with a hex value.
1859				e.g. pmtmr=0x508
1860	
1861		pnp.debug	[PNP]
1862				Enable PNP debug messages.  This depends on the
1863				CONFIG_PNP_DEBUG_MESSAGES option.
1864	
1865		pnpacpi=	[ACPI]
1866				{ off }
1867	
1868		pnpbios=	[ISAPNP]
1869				{ on | off | curr | res | no-curr | no-res }
1870	
1871		pnp_reserve_irq=
1872				[ISAPNP] Exclude IRQs for the autoconfiguration
1873	
1874		pnp_reserve_dma=
1875				[ISAPNP] Exclude DMAs for the autoconfiguration
1876	
1877		pnp_reserve_io=	[ISAPNP] Exclude I/O ports for the autoconfiguration
1878				Ranges are in pairs (I/O port base and size).
1879	
1880		pnp_reserve_mem=
1881				[ISAPNP] Exclude memory regions for the
1882				autoconfiguration.
1883				Ranges are in pairs (memory base and size).
1884	
1885		ports=		[IP_VS_FTP] IPVS ftp helper module
1886				Default is 21.
1887				Up to 8 (IP_VS_APP_MAX_PORTS) ports
1888				may be specified.
1889				Format: <port>,<port>....
1890	
1891		print-fatal-signals=
1892				[KNL] debug: print fatal signals
1893				print-fatal-signals=1: print segfault info to
1894				the kernel console.
1895				default: off.
1896	
1897		printk.time=	Show timing data prefixed to each printk message line
1898				Format: <bool>  (1/Y/y=enable, 0/N/n=disable)
1899	
1900		processor.max_cstate=	[HW,ACPI]
1901				Limit processor to maximum C-state
1902				max_cstate=9 overrides any DMI blacklist limit.
1903	
1904		processor.nocst	[HW,ACPI]
1905				Ignore the _CST method to determine C-states,
1906				instead using the legacy FADT method
1907	
1908		profile=	[KNL] Enable kernel profiling via /proc/profile
1909				Format: [schedule,]<number>
1910				Param: "schedule" - profile schedule points.
1911				Param: <number> - step/bucket size as a power of 2 for
1912					statistical time based profiling.
1913				Param: "sleep" - profile D-state sleeping (millisecs).
1914					Requires CONFIG_SCHEDSTATS
1915				Param: "kvm" - profile VM exits.
1916	
1917		prompt_ramdisk=	[RAM] List of RAM disks to prompt for floppy disk
1918				before loading.
1919				See Documentation/blockdev/ramdisk.txt.
1920	
1921		psmouse.proto=	[HW,MOUSE] Highest PS2 mouse protocol extension to
1922				probe for; one of (bare|imps|exps|lifebook|any).
1923		psmouse.rate=	[HW,MOUSE] Set desired mouse report rate, in reports
1924				per second.
1925		psmouse.resetafter=	[HW,MOUSE]
1926				Try to reset the device after so many bad packets
1927				(0 = never).
1928		psmouse.resolution=
1929				[HW,MOUSE] Set desired mouse resolution, in dpi.
1930		psmouse.smartscroll=
1931				[HW,MOUSE] Controls Logitech smartscroll autorepeat.
1932				0 = disabled, 1 = enabled (default).
1933	
1934		pss=		[HW,OSS] Personal Sound System (ECHO ESC614)
1935				Format:
1936				<io>,<mss_io>,<mss_irq>,<mss_dma>,<mpu_io>,<mpu_irq>
1937	
1938		pt.		[PARIDE]
1939				See Documentation/blockdev/paride.txt.
1940	
1941		pty.legacy_count=
1942				[KNL] Number of legacy pty's. Overwrites compiled-in
1943				default number.
1944	
1945		quiet		[KNL] Disable most log messages
1946	
1947		r128=		[HW,DRM]
1948	
1949		raid=		[HW,RAID]
1950				See Documentation/md.txt.
1951	
1952		ramdisk_blocksize=	[RAM]
1953				See Documentation/blockdev/ramdisk.txt.
1954	
1955		ramdisk_size=	[RAM] Sizes of RAM disks in kilobytes
1956				See Documentation/blockdev/ramdisk.txt.
1957	
1958		rcupdate.blimit=	[KNL,BOOT]
1959				Set maximum number of finished RCU callbacks to process
1960				in one batch.
1961	
1962		rcupdate.qhimark=	[KNL,BOOT]
1963				Set threshold of queued
1964				RCU callbacks over which batch limiting is disabled.
1965	
1966		rcupdate.qlowmark=	[KNL,BOOT]
1967				Set threshold of queued RCU callbacks below which
1968				batch limiting is re-enabled.
1969	
1970		rdinit=		[KNL]
1971				Format: <full_path>
1972				Run specified binary instead of /init from the ramdisk,
1973				used for early userspace startup. See initrd.
1974	
1975		reboot=		[BUGS=X86-32,BUGS=ARM,BUGS=IA-64] Rebooting mode
1976				Format: <reboot_mode>[,<reboot_mode2>[,...]]
1977				See arch/*/kernel/reboot.c or arch/*/kernel/process.c
1978	
1979		relax_domain_level=
1980				[KNL, SMP] Set scheduler's default relax_domain_level.
1981				See Documentation/cgroups/cpusets.txt.
1982	
1983		reserve=	[KNL,BUGS] Force the kernel to ignore some iomem area
1984	
1985		reservetop=	[X86-32]
1986				Format: nn[KMG]
1987				Reserves a hole at the top of the kernel virtual
1988				address space.
1989	
1990		reset_devices	[KNL] Force drivers to reset the underlying device
1991				during initialization.
1992	
1993		resume=		[SWSUSP]
1994				Specify the partition device for software suspend
1995	
1996		resume_offset=	[SWSUSP]
1997				Specify the offset from the beginning of the partition
1998				given by "resume=" at which the swap header is located,
1999				in <PAGE_SIZE> units (needed only for swap files).
2000				See  Documentation/power/swsusp-and-swap-files.txt
2001	
2002		retain_initrd	[RAM] Keep initrd memory after extraction
2003	
2004		rhash_entries=	[KNL,NET]
2005				Set number of hash buckets for route cache
2006	
2007		riscom8=	[HW,SERIAL]
2008				Format: <io_board1>[,<io_board2>[,...<io_boardN>]]
2009	
2010		ro		[KNL] Mount root device read-only on boot
2011	
2012		root=		[KNL] Root filesystem
2013	
2014		rootdelay=	[KNL] Delay (in seconds) to pause before attempting to
2015				mount the root filesystem
2016	
2017		rootflags=	[KNL] Set root filesystem mount option string
2018	
2019		rootfstype=	[KNL] Set root filesystem type
2020	
2021		rootwait	[KNL] Wait (indefinitely) for root device to show up.
2022				Useful for devices that are detected asynchronously
2023				(e.g. USB and MMC devices).
2024	
2025		root_plug.vendor_id=
2026				[ROOTPLUG] Override the default vendor ID
2027	
2028		root_plug.product_id=
2029				[ROOTPLUG] Override the default product ID
2030	
2031		root_plug.debug=
2032				[ROOTPLUG] Enable debugging output
2033	
2034		rw		[KNL] Mount root device read-write on boot
2035	
2036		S		[KNL] Run init in single mode
2037	
2038		sa1100ir	[NET]
2039				See drivers/net/irda/sa1100_ir.c.
2040	
2041		sbni=		[NET] Granch SBNI12 leased line adapter
2042	
2043		sc1200wdt=	[HW,WDT] SC1200 WDT (watchdog) driver
2044				Format: <io>[,<timeout>[,<isapnp>]]
2045	
2046		scsi_debug_*=	[SCSI]
2047				See drivers/scsi/scsi_debug.c.
2048	
2049		scsi_default_dev_flags=
2050				[SCSI] SCSI default device flags
2051				Format: <integer>
2052	
2053		scsi_dev_flags=	[SCSI] Black/white list entry for vendor and model
2054				Format: <vendor>:<model>:<flags>
2055				(flags are integer value)
2056	
2057		scsi_logging_level=	[SCSI] a bit mask of logging levels
2058				See drivers/scsi/scsi_logging.h for bits.  Also
2059				settable via sysctl at dev.scsi.logging_level
2060				(/proc/sys/dev/scsi/logging_level).
2061				There is also a nice 'scsi_logging_level' script in the
2062				S390-tools package, available for download at
2063				http://www-128.ibm.com/developerworks/linux/linux390/s390-tools-1.5.4.html
2064	
2065		scsi_mod.scan=	[SCSI] sync (default) scans SCSI busses as they are
2066				discovered.  async scans them in kernel threads,
2067				allowing boot to proceed.  none ignores them, expecting
2068				user space to do the scan.
2069	
2070		security=	[SECURITY] Choose a security module to enable at boot.
2071				If this boot parameter is not specified, only the first
2072				security module asking for security registration will be
2073				loaded. An invalid security module name will be treated
2074				as if no module has been chosen.
2075	
2076		selinux=	[SELINUX] Disable or enable SELinux at boot time.
2077				Format: { "0" | "1" }
2078				See security/selinux/Kconfig help text.
2079				0 -- disable.
2080				1 -- enable.
2081				Default value is set via kernel config option.
2082				If enabled at boot time, /selinux/disable can be used
2083				later to disable prior to initial policy load.
2084	
2085		serialnumber	[BUGS=X86-32]
2086	
2087		shapers=	[NET]
2088				Maximal number of shapers.
2089	
2090		show_msr=	[x86] show boot-time MSR settings
2091				Format: { <integer> }
2092				Show boot-time (BIOS-initialized) MSR settings.
2093				The parameter means the number of CPUs to show,
2094				for example 1 means boot CPU only.
2095	
2096		sim710=		[SCSI,HW]
2097				See header of drivers/scsi/sim710.c.
2098	
2099		simeth=		[IA-64]
2100		simscsi=
2101	
2102		slram=		[HW,MTD]
2103	
2104		slub_debug[=options[,slabs]]	[MM, SLUB]
2105				Enabling slub_debug allows one to determine the
2106				culprit if slab objects become corrupted. Enabling
2107				slub_debug can create guard zones around objects and
2108				may poison objects when not in use. Also tracks the
2109				last alloc / free. For more information see
2110				Documentation/vm/slub.txt.
2111	
2112		slub_max_order= [MM, SLUB]
2113				Determines the maximum allowed order for slabs.
2114				A high setting may cause OOMs due to memory
2115				fragmentation. For more information see
2116				Documentation/vm/slub.txt.
2117	
2118		slub_min_objects=	[MM, SLUB]
2119				The minimum number of objects per slab. SLUB will
2120				increase the slab order up to slub_max_order to
2121				generate a sufficiently large slab able to contain
2122				the number of objects indicated. The higher the number
2123				of objects the smaller the overhead of tracking slabs
2124				and the less frequently locks need to be acquired.
2125				For more information see Documentation/vm/slub.txt.
2126	
2127		slub_min_order=	[MM, SLUB]
2128				Determines the mininum page order for slabs. Must be
2129				lower than slub_max_order.
2130				For more information see Documentation/vm/slub.txt.
2131	
2132		slub_nomerge	[MM, SLUB]
2133				Disable merging of slabs with similar size. May be
2134				necessary if there is some reason to distinguish
2135				allocs to different slabs. Debug options disable
2136				merging on their own.
2137				For more information see Documentation/vm/slub.txt.
2138	
2139		smart2=		[HW]
2140				Format: <io1>[,<io2>[,...,<io8>]]
2141	
2142		smp-alt-once	[X86-32,SMP] On a hotplug CPU system, only
2143				attempt to substitute SMP alternatives once at boot.
2144	
2145		smsc-ircc2.nopnp	[HW] Don't use PNP to discover SMC devices
2146		smsc-ircc2.ircc_cfg=	[HW] Device configuration I/O port
2147		smsc-ircc2.ircc_sir=	[HW] SIR base I/O port
2148		smsc-ircc2.ircc_fir=	[HW] FIR base I/O port
2149		smsc-ircc2.ircc_irq=	[HW] IRQ line
2150		smsc-ircc2.ircc_dma=	[HW] DMA channel
2151		smsc-ircc2.ircc_transceiver= [HW] Transceiver type:
2152					0: Toshiba Satellite 1800 (GP data pin select)
2153					1: Fast pin select (default)
2154					2: ATC IRMode
2155	
2156		snd-ad1816a=	[HW,ALSA]
2157	
2158		snd-ad1848=	[HW,ALSA]
2159	
2160		snd-ali5451=	[HW,ALSA]
2161	
2162		snd-als100=	[HW,ALSA]
2163	
2164		snd-als4000=	[HW,ALSA]
2165	
2166		snd-azt2320=	[HW,ALSA]
2167	
2168		snd-cmi8330=	[HW,ALSA]
2169	
2170		snd-cmipci=	[HW,ALSA]
2171	
2172		snd-cs4231=	[HW,ALSA]
2173	
2174		snd-cs4232=	[HW,ALSA]
2175	
2176		snd-cs4236=	[HW,ALSA]
2177	
2178		snd-cs4281=	[HW,ALSA]
2179	
2180		snd-cs46xx=	[HW,ALSA]
2181	
2182		snd-dt019x=	[HW,ALSA]
2183	
2184		snd-dummy=	[HW,ALSA]
2185	
2186		snd-emu10k1=	[HW,ALSA]
2187	
2188		snd-ens1370=	[HW,ALSA]
2189	
2190		snd-ens1371=	[HW,ALSA]
2191	
2192		snd-es968=	[HW,ALSA]
2193	
2194		snd-es1688=	[HW,ALSA]
2195	
2196		snd-es18xx=	[HW,ALSA]
2197	
2198		snd-es1938=	[HW,ALSA]
2199	
2200		snd-es1968=	[HW,ALSA]
2201	
2202		snd-fm801=	[HW,ALSA]
2203	
2204		snd-gusclassic=	[HW,ALSA]
2205	
2206		snd-gusextreme=	[HW,ALSA]
2207	
2208		snd-gusmax=	[HW,ALSA]
2209	
2210		snd-hdsp=	[HW,ALSA]
2211	
2212		snd-ice1712=	[HW,ALSA]
2213	
2214		snd-intel8x0=	[HW,ALSA]
2215	
2216		snd-interwave=	[HW,ALSA]
2217	
2218		snd-interwave-stb=
2219				[HW,ALSA]
2220	
2221		snd-korg1212=	[HW,ALSA]
2222	
2223		snd-maestro3=	[HW,ALSA]
2224	
2225		snd-mpu401=	[HW,ALSA]
2226	
2227		snd-mtpav=	[HW,ALSA]
2228	
2229		snd-nm256=	[HW,ALSA]
2230	
2231		snd-opl3sa2=	[HW,ALSA]
2232	
2233		snd-opti92x-ad1848=
2234				[HW,ALSA]
2235	
2236		snd-opti92x-cs4231=
2237				[HW,ALSA]
2238	
2239		snd-opti93x=	[HW,ALSA]
2240	
2241		snd-pmac=	[HW,ALSA]
2242	
2243		snd-rme32=	[HW,ALSA]
2244	
2245		snd-rme96=	[HW,ALSA]
2246	
2247		snd-rme9652=	[HW,ALSA]
2248	
2249		snd-sb8=	[HW,ALSA]
2250	
2251		snd-sb16=	[HW,ALSA]
2252	
2253		snd-sbawe=	[HW,ALSA]
2254	
2255		snd-serial=	[HW,ALSA]
2256	
2257		snd-sgalaxy=	[HW,ALSA]
2258	
2259		snd-sonicvibes=	[HW,ALSA]
2260	
2261		snd-sun-amd7930=
2262				[HW,ALSA]
2263	
2264		snd-sun-cs4231=	[HW,ALSA]
2265	
2266		snd-trident=	[HW,ALSA]
2267	
2268		snd-usb-audio=	[HW,ALSA,USB]
2269	
2270		snd-via82xx=	[HW,ALSA]
2271	
2272		snd-virmidi=	[HW,ALSA]
2273	
2274		snd-wavefront=	[HW,ALSA]
2275	
2276		snd-ymfpci=	[HW,ALSA]
2277	
2278		softlockup_panic=
2279				[KNL] Should the soft-lockup detector generate panics.
2280	
2281		sonypi.*=	[HW] Sony Programmable I/O Control Device driver
2282				See Documentation/sonypi.txt
2283	
2284		specialix=	[HW,SERIAL] Specialix multi-serial port adapter
2285				See Documentation/serial/specialix.txt.
2286	
2287		spia_io_base=	[HW,MTD]
2288		spia_fio_base=
2289		spia_pedr=
2290		spia_peddr=
2291	
2292		sscape=		[HW,OSS]
2293				Format: <io>,<irq>,<dma>,<mpu_io>,<mpu_irq>
2294	
2295		st=		[HW,SCSI] SCSI tape parameters (buffers, etc.)
2296				See Documentation/scsi/st.txt.
2297	
2298		stacktrace	[FTRACE]
2299				Enabled the stack tracer on boot up.
2300	
2301		sti=		[PARISC,HW]
2302				Format: <num>
2303				Set the STI (builtin display/keyboard on the HP-PARISC
2304				machines) console (graphic card) which should be used
2305				as the initial boot-console.
2306				See also comment in drivers/video/console/sticore.c.
2307	
2308		sti_font=	[HW]
2309				See comment in drivers/video/console/sticore.c.
2310	
2311		stifb=		[HW]
2312				Format: bpp:<bpp1>[:<bpp2>[:<bpp3>...]]
2313	
2314		sunrpc.pool_mode=
2315				[NFS]
2316				Control how the NFS server code allocates CPUs to
2317				service thread pools.  Depending on how many NICs
2318				you have and where their interrupts are bound, this
2319				option will affect which CPUs will do NFS serving.
2320				Note: this parameter cannot be changed while the
2321				NFS server is running.
2322	
2323				auto	    the server chooses an appropriate mode
2324					    automatically using heuristics
2325				global	    a single global pool contains all CPUs
2326				percpu	    one pool for each CPU
2327				pernode	    one pool for each NUMA node (equivalent
2328					    to global on non-NUMA machines)
2329	
2330		swiotlb=	[IA-64] Number of I/O TLB slabs
2331	
2332		switches=	[HW,M68k]
2333	
2334		sym53c416=	[HW,SCSI]
2335				See header of drivers/scsi/sym53c416.c.
2336	
2337		sysrq_always_enabled
2338				[KNL]
2339				Ignore sysrq setting - this boot parameter will
2340				neutralize any effect of /proc/sys/kernel/sysrq.
2341				Useful for debugging.
2342	
2343		t128=		[HW,SCSI]
2344				See header of drivers/scsi/t128.c.
2345	
2346		tdfx=		[HW,DRM]
2347	
2348		test_suspend=	[SUSPEND]
2349				Specify "mem" (for Suspend-to-RAM) or "standby" (for
2350				standby suspend) as the system sleep state to briefly
2351				enter during system startup.  The system is woken from
2352				this state using a wakeup-capable RTC alarm.
2353	
2354		thash_entries=	[KNL,NET]
2355				Set number of hash buckets for TCP connection
2356	
2357		thermal.act=	[HW,ACPI]
2358				-1: disable all active trip points in all thermal zones
2359				<degrees C>: override all lowest active trip points
2360	
2361		thermal.crt=	[HW,ACPI]
2362				-1: disable all critical trip points in all thermal zones
2363				<degrees C>: override all critical trip points
2364	
2365		thermal.nocrt=	[HW,ACPI]
2366				Set to disable actions on ACPI thermal zone
2367				critical and hot trip points.
2368	
2369		thermal.off=	[HW,ACPI]
2370				1: disable ACPI thermal control
2371	
2372		thermal.psv=	[HW,ACPI]
2373				-1: disable all passive trip points
2374				<degrees C>: override all passive trip points to this
2375				value
2376	
2377		thermal.tzp=	[HW,ACPI]
2378				Specify global default ACPI thermal zone polling rate
2379				<deci-seconds>: poll all this frequency
2380				0: no polling (default)
2381	
2382		tmscsim=	[HW,SCSI]
2383				See comment before function dc390_setup() in
2384				drivers/scsi/tmscsim.c.
2385	
2386		topology=	[S390]
2387				Format: {off | on}
2388				Specify if the kernel should make use of the cpu
2389				topology informations if the hardware supports these.
2390				The scheduler will make use of these informations and
2391				e.g. base its process migration decisions on it.
2392				Default is off.
2393	
2394		tp720=		[HW,PS2]
2395	
2396		trace_buf_size=nn[KMG] [ftrace] will set tracing buffer size.
2397	
2398		trix=		[HW,OSS] MediaTrix AudioTrix Pro
2399				Format:
2400				<io>,<irq>,<dma>,<dma2>,<sb_io>,<sb_irq>,<sb_dma>,<mpu_io>,<mpu_irq>
2401	
2402		tsc=		Disable clocksource-must-verify flag for TSC.
2403				Format: <string>
2404				[x86] reliable: mark tsc clocksource as reliable, this
2405				disables clocksource verification at runtime.
2406				Used to enable high-resolution timer mode on older
2407				hardware, and in virtualized environment.
2408	
2409		turbografx.map[2|3]=	[HW,JOY]
2410				TurboGraFX parallel port interface
2411				Format:
2412				<port#>,<js1>,<js2>,<js3>,<js4>,<js5>,<js6>,<js7>
2413				See also Documentation/input/joystick-parport.txt
2414	
2415		u14-34f=	[HW,SCSI] UltraStor 14F/34F SCSI host adapter
2416				See header of drivers/scsi/u14-34f.c.
2417	
2418		uart401=	[HW,OSS]
2419				Format: <io>,<irq>
2420	
2421		uart6850=	[HW,OSS]
2422				Format: <io>,<irq>
2423	
2424		uhci-hcd.ignore_oc=
2425				[USB] Ignore overcurrent events (default N).
2426				Some badly-designed motherboards generate lots of
2427				bogus events, for ports that aren't wired to
2428				anything.  Set this parameter to avoid log spamming.
2429				Note that genuine overcurrent events won't be
2430				reported either.
2431	
2432		unknown_nmi_panic
2433				[X86]
2434				Set unknown_nmi_panic=1 early on boot.
2435	
2436		usbcore.autosuspend=
2437				[USB] The autosuspend time delay (in seconds) used
2438				for newly-detected USB devices (default 2).  This
2439				is the time required before an idle device will be
2440				autosuspended.  Devices for which the delay is set
2441				to a negative value won't be autosuspended at all.
2442	
2443		usbcore.usbfs_snoop=
2444				[USB] Set to log all usbfs traffic (default 0 = off).
2445	
2446		usbcore.blinkenlights=
2447				[USB] Set to cycle leds on hubs (default 0 = off).
2448	
2449		usbcore.old_scheme_first=
2450				[USB] Start with the old device initialization
2451				scheme (default 0 = off).
2452	
2453		usbcore.use_both_schemes=
2454				[USB] Try the other device initialization scheme
2455				if the first one fails (default 1 = enabled).
2456	
2457		usbcore.initial_descriptor_timeout=
2458				[USB] Specifies timeout for the initial 64-byte
2459	                        USB_REQ_GET_DESCRIPTOR request in milliseconds
2460				(default 5000 = 5.0 seconds).
2461	
2462		usbhid.mousepoll=
2463				[USBHID] The interval which mice are to be polled at.
2464	
2465		usb-storage.delay_use=
2466				[UMS] The delay in seconds before a new device is
2467				scanned for Logical Units (default 5).
2468	
2469		usb-storage.quirks=
2470				[UMS] A list of quirks entries to supplement or
2471				override the built-in unusual_devs list.  List
2472				entries are separated by commas.  Each entry has
2473				the form VID:PID:Flags where VID and PID are Vendor
2474				and Product ID values (4-digit hex numbers) and
2475				Flags is a set of characters, each corresponding
2476				to a common usb-storage quirk flag as follows:
2477					a = SANE_SENSE (collect more than 18 bytes
2478						of sense data);
2479					c = FIX_CAPACITY (decrease the reported
2480						device capacity by one sector);
2481					h = CAPACITY_HEURISTICS (decrease the
2482						reported device capacity by one
2483						sector if the number is odd);
2484					i = IGNORE_DEVICE (don't bind to this
2485						device);
2486					l = NOT_LOCKABLE (don't try to lock and
2487						unlock ejectable media);
2488					m = MAX_SECTORS_64 (don't transfer more
2489						than 64 sectors = 32 KB at a time);
2490					o = CAPACITY_OK (accept the capacity
2491						reported by the device);
2492					r = IGNORE_RESIDUE (the device reports
2493						bogus residue values);
2494					s = SINGLE_LUN (the device has only one
2495						Logical Unit);
2496					w = NO_WP_DETECT (don't test whether the
2497						medium is write-protected).
2498				Example: quirks=0419:aaf5:rl,0421:0433:rc
2499	
2500		vdso=		[X86,SH]
2501				vdso=2: enable compat VDSO (default with COMPAT_VDSO)
2502				vdso=1: enable VDSO (default)
2503				vdso=0: disable VDSO mapping
2504	
2505		vdso32=		[X86]
2506				vdso32=2: enable compat VDSO (default with COMPAT_VDSO)
2507				vdso32=1: enable 32-bit VDSO (default)
2508				vdso32=0: disable 32-bit VDSO mapping
2509	
2510		vector=		[IA-64,SMP]
2511				vector=percpu: enable percpu vector domain
2512	
2513		video=		[FB] Frame buffer configuration
2514				See Documentation/fb/modedb.txt.
2515	
2516		vga=		[BOOT,X86-32] Select a particular video mode
2517				See Documentation/x86/boot.txt and
2518				Documentation/svga.txt.
2519				Use vga=ask for menu.
2520				This is actually a boot loader parameter; the value is
2521				passed to the kernel using a special protocol.
2522	
2523		vmalloc=nn[KMG]	[KNL,BOOT] Forces the vmalloc area to have an exact
2524				size of <nn>. This can be used to increase the
2525				minimum size (128MB on x86). It can also be used to
2526				decrease the size and leave more room for directly
2527				mapped kernel RAM.
2528	
2529		vmhalt=		[KNL,S390] Perform z/VM CP command after system halt.
2530				Format: <command>
2531	
2532		vmpanic=	[KNL,S390] Perform z/VM CP command after kernel panic.
2533				Format: <command>
2534	
2535		vmpoff=		[KNL,S390] Perform z/VM CP command after power off.
2536				Format: <command>
2537	
2538		vt.default_blu=	[VT]
2539				Format: <blue0>,<blue1>,<blue2>,...,<blue15>
2540				Change the default blue palette of the console.
2541				This is a 16-member array composed of values
2542				ranging from 0-255.
2543	
2544		vt.default_grn=	[VT]
2545				Format: <green0>,<green1>,<green2>,...,<green15>
2546				Change the default green palette of the console.
2547				This is a 16-member array composed of values
2548				ranging from 0-255.
2549	
2550		vt.default_red=	[VT]
2551				Format: <red0>,<red1>,<red2>,...,<red15>
2552				Change the default red palette of the console.
2553				This is a 16-member array composed of values
2554				ranging from 0-255.
2555	
2556		vt.default_utf8=
2557				[VT]
2558				Format=<0|1>
2559				Set system-wide default UTF-8 mode for all tty's.
2560				Default is 1, i.e. UTF-8 mode is enabled for all
2561				newly opened terminals.
2562	
2563		waveartist=	[HW,OSS]
2564				Format: <io>,<irq>,<dma>,<dma2>
2565	
2566		wd33c93=	[HW,SCSI]
2567				See header of drivers/scsi/wd33c93.c.
2568	
2569		wd7000=		[HW,SCSI]
2570				See header of drivers/scsi/wd7000.c.
2571	
2572		wdt=		[WDT] Watchdog
2573				See Documentation/watchdog/wdt.txt.
2574	
2575		x2apic_phys	[X86-64,APIC] Use x2apic physical mode instead of
2576				default x2apic cluster mode on platforms
2577				supporting x2apic.
2578	
2579		xd=		[HW,XT] Original XT pre-IDE (RLL encoded) disks.
2580		xd_geo=		See header of drivers/block/xd.c.
2581	
2582		xirc2ps_cs=	[NET,PCMCIA]
2583				Format:
2584				<irq>,<irq_mask>,<io>,<full_duplex>,<do_sound>,<lockup_hack>[,<irq2>[,<irq3>[,<irq4>]]]
2585	
2586	______________________________________________________________________
2587	
2588	TODO:
2589	
2590		Add documentation for ALSA options.
2591		Add more DRM drivers.
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