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Based on kernel version 2.6.33. Page generated on 2010-02-24 15:36 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		GCOV	GCOV profiling is enabled.
52		HW	Appropriate hardware is enabled.
53		IA-64	IA-64 architecture is enabled.
54		IMA     Integrity measurement architecture is enabled.
55		IOSCHED	More than one I/O scheduler is enabled.
56		IP_PNP	IP DHCP, BOOTP, or RARP is enabled.
57		ISAPNP	ISA PnP code is enabled.
58		ISDN	Appropriate ISDN support is enabled.
59		JOY	Appropriate joystick support is enabled.
60		KVM	Kernel Virtual Machine support is enabled.
61		LIBATA  Libata driver is enabled
62		LP	Printer support is enabled.
63		LOOP	Loopback device support is enabled.
64		M68k	M68k architecture is enabled.
65				These options have more detailed description inside of
66				Documentation/m68k/kernel-options.txt.
67		MCA	MCA bus support is enabled.
68		MDA	MDA console support is enabled.
69		MOUSE	Appropriate mouse support is enabled.
70		MSI	Message Signaled Interrupts (PCI).
71		MTD	MTD (Memory Technology Device) support is enabled.
72		NET	Appropriate network support is enabled.
73		NUMA	NUMA support is enabled.
74		GENERIC_TIME The generic timeofday code is enabled.
75		NFS	Appropriate NFS support is enabled.
76		OSS	OSS sound support is enabled.
77		PV_OPS	A paravirtualized kernel is enabled.
78		PARIDE	The ParIDE (parallel port IDE) subsystem is enabled.
79		PARISC	The PA-RISC architecture is enabled.
80		PCI	PCI bus support is enabled.
81		PCIE	PCI Express support is enabled.
82		PCMCIA	The PCMCIA subsystem is enabled.
83		PNP	Plug & Play support is enabled.
84		PPC	PowerPC architecture is enabled.
85		PPT	Parallel port support is enabled.
86		PS2	Appropriate PS/2 support is enabled.
87		RAM	RAM disk support 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_early_pdc_eval	[HW,ACPI] Evaluate processor _PDC methods
203					early. Needed on some platforms to properly
204					initialize the EC.
205	
206		acpi_irq_balance [HW,ACPI]
207				ACPI will balance active IRQs
208				default in APIC mode
209	
210		acpi_irq_nobalance [HW,ACPI]
211				ACPI will not move active IRQs (default)
212				default in PIC mode
213	
214		acpi_irq_isa=	[HW,ACPI] If irq_balance, mark listed IRQs used by ISA
215				Format: <irq>,<irq>...
216	
217		acpi_irq_pci=	[HW,ACPI] If irq_balance, clear listed IRQs for
218				use by PCI
219				Format: <irq>,<irq>...
220	
221		acpi_no_auto_ssdt	[HW,ACPI] Disable automatic loading of SSDT
222	
223		acpi_os_name=	[HW,ACPI] Tell ACPI BIOS the name of the OS
224				Format: To spoof as Windows 98: ="Microsoft Windows"
225	
226		acpi_osi=	[HW,ACPI] Modify list of supported OS interface strings
227				acpi_osi="string1"	# add string1 -- only one string
228				acpi_osi="!string2"	# remove built-in string2
229				acpi_osi=		# disable all strings
230	
231		acpi_pm_good	[X86]
232				Override the pmtimer bug detection: force the kernel
233				to assume that this machine's pmtimer latches its value
234				and always returns good values.
235	
236		acpi_sci=	[HW,ACPI] ACPI System Control Interrupt trigger mode
237				Format: { level | edge | high | low }
238	
239		acpi_serialize	[HW,ACPI] force serialization of AML methods
240	
241		acpi_skip_timer_override [HW,ACPI]
242				Recognize and ignore IRQ0/pin2 Interrupt Override.
243				For broken nForce2 BIOS resulting in XT-PIC timer.
244	
245		acpi_sleep=	[HW,ACPI] Sleep options
246				Format: { s3_bios, s3_mode, s3_beep, s4_nohwsig,
247					  old_ordering, s4_nonvs, sci_force_enable }
248				See Documentation/power/video.txt for information on
249				s3_bios and s3_mode.
250				s3_beep is for debugging; it makes the PC's speaker beep
251				as soon as the kernel's real-mode entry point is called.
252				s4_nohwsig prevents ACPI hardware signature from being
253				used during resume from hibernation.
254				old_ordering causes the ACPI 1.0 ordering of the _PTS
255				control method, with respect to putting devices into
256				low power states, to be enforced (the ACPI 2.0 ordering
257				of _PTS is used by default).
258				s4_nonvs prevents the kernel from saving/restoring the
259				ACPI NVS memory during hibernation.
260				sci_force_enable causes the kernel to set SCI_EN directly
261				on resume from S1/S3 (which is against the ACPI spec,
262				but some broken systems don't work without it).
263	
264		acpi_use_timer_override [HW,ACPI]
265				Use timer override. For some broken Nvidia NF5 boards
266				that require a timer override, but don't have HPET
267	
268		acpi_enforce_resources=	[ACPI]
269				{ strict | lax | no }
270				Check for resource conflicts between native drivers
271				and ACPI OperationRegions (SystemIO and SystemMemory
272				only). IO ports and memory declared in ACPI might be
273				used by the ACPI subsystem in arbitrary AML code and
274				can interfere with legacy drivers.
275				strict (default): access to resources claimed by ACPI
276				is denied; legacy drivers trying to access reserved
277				resources will fail to bind to device using them.
278				lax: access to resources claimed by ACPI is allowed;
279				legacy drivers trying to access reserved resources
280				will bind successfully but a warning message is logged.
281				no: ACPI OperationRegions are not marked as reserved,
282				no further checks are performed.
283	
284		ad1848=		[HW,OSS]
285				Format: <io>,<irq>,<dma>,<dma2>,<type>
286	
287		add_efi_memmap	[EFI; X86] Include EFI memory map in
288				kernel's map of available physical RAM.
289	
290		advansys=	[HW,SCSI]
291				See header of drivers/scsi/advansys.c.
292	
293		advwdt=		[HW,WDT] Advantech WDT
294				Format: <iostart>,<iostop>
295	
296		aedsp16=	[HW,OSS] Audio Excel DSP 16
297				Format: <io>,<irq>,<dma>,<mss_io>,<mpu_io>,<mpu_irq>
298				See also header of sound/oss/aedsp16.c.
299	
300		agp=		[AGP]
301				{ off | try_unsupported }
302				off: disable AGP support
303				try_unsupported: try to drive unsupported chipsets
304					(may crash computer or cause data corruption)
305	
306		aha152x=	[HW,SCSI]
307				See Documentation/scsi/aha152x.txt.
308	
309		aha1542=	[HW,SCSI]
310				Format: <portbase>[,<buson>,<busoff>[,<dmaspeed>]]
311	
312		aic7xxx=	[HW,SCSI]
313				See Documentation/scsi/aic7xxx.txt.
314	
315		aic79xx=	[HW,SCSI]
316				See Documentation/scsi/aic79xx.txt.
317	
318		alignment=	[KNL,ARM]
319				Allow the default userspace alignment fault handler
320				behaviour to be specified.  Bit 0 enables warnings,
321				bit 1 enables fixups, and bit 2 sends a segfault.
322	
323		amd_iommu=	[HW,X86-84]
324				Pass parameters to the AMD IOMMU driver in the system.
325				Possible values are:
326				isolate - enable device isolation (each device, as far
327				          as possible, will get its own protection
328				          domain) [default]
329				share - put every device behind one IOMMU into the
330					same protection domain
331				fullflush - enable flushing of IO/TLB entries when
332					    they are unmapped. Otherwise they are
333					    flushed before they will be reused, which
334					    is a lot of faster
335	
336		amijoy.map=	[HW,JOY] Amiga joystick support
337				Map of devices attached to JOY0DAT and JOY1DAT
338				Format: <a>,<b>
339				See also Documentation/kernel/input/joystick.txt
340	
341		analog.map=	[HW,JOY] Analog joystick and gamepad support
342				Specifies type or capabilities of an analog joystick
343				connected to one of 16 gameports
344				Format: <type1>,<type2>,..<type16>
345	
346		apc=		[HW,SPARC]
347				Power management functions (SPARCstation-4/5 + deriv.)
348				Format: noidle
349				Disable APC CPU standby support. SPARCstation-Fox does
350				not play well with APC CPU idle - disable it if you have
351				APC and your system crashes randomly.
352	
353		apic=		[APIC,X86-32] Advanced Programmable Interrupt Controller
354				Change the output verbosity whilst booting
355				Format: { quiet (default) | verbose | debug }
356				Change the amount of debugging information output
357				when initialising the APIC and IO-APIC components.
358	
359		show_lapic=	[APIC,X86] Advanced Programmable Interrupt Controller
360				Limit apic dumping. The parameter defines the maximal
361				number of local apics being dumped. Also it is possible
362				to set it to "all" by meaning -- no limit here.
363				Format: { 1 (default) | 2 | ... | all }.
364				The parameter valid if only apic=debug or
365				apic=verbose is specified.
366				Example: apic=debug show_lapic=all
367	
368		apm=		[APM] Advanced Power Management
369				See header of arch/x86/kernel/apm_32.c.
370	
371		arcrimi=	[HW,NET] ARCnet - "RIM I" (entirely mem-mapped) cards
372				Format: <io>,<irq>,<nodeID>
373	
374		ataflop=	[HW,M68k]
375	
376		atarimouse=	[HW,MOUSE] Atari Mouse
377	
378		atascsi=	[HW,SCSI] Atari SCSI
379	
380		atkbd.extra=	[HW] Enable extra LEDs and keys on IBM RapidAccess,
381				EzKey and similar keyboards
382	
383		atkbd.reset=	[HW] Reset keyboard during initialization
384	
385		atkbd.set=	[HW] Select keyboard code set
386				Format: <int> (2 = AT (default), 3 = PS/2)
387	
388		atkbd.scroll=	[HW] Enable scroll wheel on MS Office and similar
389				keyboards
390	
391		atkbd.softraw=	[HW] Choose between synthetic and real raw mode
392				Format: <bool> (0 = real, 1 = synthetic (default))
393	
394		atkbd.softrepeat= [HW]
395				Use software keyboard repeat
396	
397		autotest	[IA64]
398	
399		baycom_epp=	[HW,AX25]
400				Format: <io>,<mode>
401	
402		baycom_par=	[HW,AX25] BayCom Parallel Port AX.25 Modem
403				Format: <io>,<mode>
404				See header of drivers/net/hamradio/baycom_par.c.
405	
406		baycom_ser_fdx=	[HW,AX25]
407				BayCom Serial Port AX.25 Modem (Full Duplex Mode)
408				Format: <io>,<irq>,<mode>[,<baud>]
409				See header of drivers/net/hamradio/baycom_ser_fdx.c.
410	
411		baycom_ser_hdx=	[HW,AX25]
412				BayCom Serial Port AX.25 Modem (Half Duplex Mode)
413				Format: <io>,<irq>,<mode>
414				See header of drivers/net/hamradio/baycom_ser_hdx.c.
415	
416		boot_delay=	Milliseconds to delay each printk during boot.
417				Values larger than 10 seconds (10000) are changed to
418				no delay (0).
419				Format: integer
420	
421		bootmem_debug	[KNL] Enable bootmem allocator debug messages.
422	
423		bttv.card=	[HW,V4L] bttv (bt848 + bt878 based grabber cards)
424		bttv.radio=	Most important insmod options are available as
425				kernel args too.
426		bttv.pll=	See Documentation/video4linux/bttv/Insmod-options
427		bttv.tuner=	and Documentation/video4linux/bttv/CARDLIST
428	
429		BusLogic=	[HW,SCSI]
430				See drivers/scsi/BusLogic.c, comment before function
431				BusLogic_ParseDriverOptions().
432	
433		c101=		[NET] Moxa C101 synchronous serial card
434	
435		cachesize=	[BUGS=X86-32] Override level 2 CPU cache size detection.
436				Sometimes CPU hardware bugs make them report the cache
437				size incorrectly. The kernel will attempt work arounds
438				to fix known problems, but for some CPUs it is not
439				possible to determine what the correct size should be.
440				This option provides an override for these situations.
441	
442		capability.disable=
443				[SECURITY] Disable capabilities.  This would normally
444				be used only if an alternative security model is to be
445				configured.  Potentially dangerous and should only be
446				used if you are entirely sure of the consequences.
447	
448		ccw_timeout_log [S390]
449				See Documentation/s390/CommonIO for details.
450	
451		cgroup_disable= [KNL] Disable a particular controller
452				Format: {name of the controller(s) to disable}
453					{Currently supported controllers - "memory"}
454	
455		checkreqprot	[SELINUX] Set initial checkreqprot flag value.
456				Format: { "0" | "1" }
457				See security/selinux/Kconfig help text.
458				0 -- check protection applied by kernel (includes
459					any implied execute protection).
460				1 -- check protection requested by application.
461				Default value is set via a kernel config option.
462				Value can be changed at runtime via
463					/selinux/checkreqprot.
464	
465		cio_ignore=	[S390]
466				See Documentation/s390/CommonIO for details.
467	
468		clock=		[BUGS=X86-32, HW] gettimeofday clocksource override.
469				[Deprecated]
470				Forces specified clocksource (if available) to be used
471				when calculating gettimeofday(). If specified
472				clocksource is not available, it defaults to PIT.
473				Format: { pit | tsc | cyclone | pmtmr }
474	
475		clocksource=	[GENERIC_TIME] Override the default clocksource
476				Format: <string>
477				Override the default clocksource and use the clocksource
478				with the name specified.
479				Some clocksource names to choose from, depending on
480				the platform:
481				[all] jiffies (this is the base, fallback clocksource)
482				[ACPI] acpi_pm
483				[ARM] imx_timer1,OSTS,netx_timer,mpu_timer2,
484					pxa_timer,timer3,32k_counter,timer0_1
485				[AVR32] avr32
486				[X86-32] pit,hpet,tsc,vmi-timer;
487					scx200_hrt on Geode; cyclone on IBM x440
488				[MIPS] MIPS
489				[PARISC] cr16
490				[S390] tod
491				[SH] SuperH
492				[SPARC64] tick
493				[X86-64] hpet,tsc
494	
495		clearcpuid=BITNUM [X86]
496				Disable CPUID feature X for the kernel. See
497				arch/x86/include/asm/cpufeature.h for the valid bit
498				numbers. Note the Linux specific bits are not necessarily
499				stable over kernel options, but the vendor specific
500				ones should be.
501				Also note that user programs calling CPUID directly
502				or using the feature without checking anything
503				will still see it. This just prevents it from
504				being used by the kernel or shown in /proc/cpuinfo.
505				Also note the kernel might malfunction if you disable
506				some critical bits.
507	
508		cmo_free_hint=	[PPC] Format: { yes | no }
509				Specify whether pages are marked as being inactive
510				when they are freed.  This is used in CMO environments
511				to determine OS memory pressure for page stealing by
512				a hypervisor.
513				Default: yes
514	
515		code_bytes	[X86] How many bytes of object code to print
516				in an oops report.
517				Range: 0 - 8192
518				Default: 64
519	
520		com20020=	[HW,NET] ARCnet - COM20020 chipset
521				Format:
522				<io>[,<irq>[,<nodeID>[,<backplane>[,<ckp>[,<timeout>]]]]]
523	
524		com90io=	[HW,NET] ARCnet - COM90xx chipset (IO-mapped buffers)
525				Format: <io>[,<irq>]
526	
527		com90xx=	[HW,NET]
528				ARCnet - COM90xx chipset (memory-mapped buffers)
529				Format: <io>[,<irq>[,<memstart>]]
530	
531		condev=		[HW,S390] console device
532		conmode=
533	
534		console=	[KNL] Output console device and options.
535	
536			tty<n>	Use the virtual console device <n>.
537	
538			ttyS<n>[,options]
539			ttyUSB0[,options]
540				Use the specified serial port.  The options are of
541				the form "bbbbpnf", where "bbbb" is the baud rate,
542				"p" is parity ("n", "o", or "e"), "n" is number of
543				bits, and "f" is flow control ("r" for RTS or
544				omit it).  Default is "9600n8".
545	
546				See Documentation/serial-console.txt for more
547				information.  See
548				Documentation/networking/netconsole.txt for an
549				alternative.
550	
551			uart[8250],io,<addr>[,options]
552			uart[8250],mmio,<addr>[,options]
553				Start an early, polled-mode console on the 8250/16550
554				UART at the specified I/O port or MMIO address,
555				switching to the matching ttyS device later.  The
556				options are the same as for ttyS, above.
557	
558	                If the device connected to the port is not a TTY but a braille
559	                device, prepend "brl," before the device type, for instance
560				console=brl,ttyS0
561			For now, only VisioBraille is supported.
562	
563		consoleblank=	[KNL] The console blank (screen saver) timeout in
564				seconds. Defaults to 10*60 = 10mins. A value of 0
565				disables the blank timer.
566	
567		coredump_filter=
568				[KNL] Change the default value for
569				/proc/<pid>/coredump_filter.
570				See also Documentation/filesystems/proc.txt.
571	
572		cpcihp_generic=	[HW,PCI] Generic port I/O CompactPCI driver
573				Format:
574				<first_slot>,<last_slot>,<port>,<enum_bit>[,<debug>]
575	
576		crashkernel=nn[KMG]@ss[KMG]
577				[KNL] Reserve a chunk of physical memory to
578				hold a kernel to switch to with kexec on panic.
579	
580		crashkernel=range1:size1[,range2:size2,...][@offset]
581				[KNL] Same as above, but depends on the memory
582				in the running system. The syntax of range is
583				start-[end] where start and end are both
584				a memory unit (amount[KMG]). See also
585				Documentation/kdump/kdump.txt for a example.
586	
587		cs89x0_dma=	[HW,NET]
588				Format: <dma>
589	
590		cs89x0_media=	[HW,NET]
591				Format: { rj45 | aui | bnc }
592	
593		dasd=		[HW,NET]
594				See header of drivers/s390/block/dasd_devmap.c.
595	
596		db9.dev[2|3]=	[HW,JOY] Multisystem joystick support via parallel port
597				(one device per port)
598				Format: <port#>,<type>
599				See also Documentation/input/joystick-parport.txt
600	
601		debug		[KNL] Enable kernel debugging (events log level).
602	
603		debug_locks_verbose=
604				[KNL] verbose self-tests
605				Format=<0|1>
606				Print debugging info while doing the locking API
607				self-tests.
608				We default to 0 (no extra messages), setting it to
609				1 will print _a lot_ more information - normally
610				only useful to kernel developers.
611	
612		debug_objects	[KNL] Enable object debugging
613	
614		no_debug_objects
615				[KNL] Disable object debugging
616	
617		debugpat	[X86] Enable PAT debugging
618	
619		decnet.addr=	[HW,NET]
620				Format: <area>[,<node>]
621				See also Documentation/networking/decnet.txt.
622	
623		default_hugepagesz=
624				[same as hugepagesz=] The size of the default
625				HugeTLB page size. This is the size represented by
626				the legacy /proc/ hugepages APIs, used for SHM, and
627				default size when mounting hugetlbfs filesystems.
628				Defaults to the default architecture's huge page size
629				if not specified.
630	
631		dhash_entries=	[KNL]
632				Set number of hash buckets for dentry cache.
633	
634		digi=		[HW,SERIAL]
635				IO parameters + enable/disable command.
636	
637		digiepca=	[HW,SERIAL]
638				See drivers/char/README.epca and
639				Documentation/serial/digiepca.txt.
640	
641		disable_mtrr_cleanup [X86]
642				The kernel tries to adjust MTRR layout from continuous
643				to discrete, to make X server driver able to add WB
644				entry later. This parameter disables that.
645	
646		disable_mtrr_trim [X86, Intel and AMD only]
647				By default the kernel will trim any uncacheable
648				memory out of your available memory pool based on
649				MTRR settings.  This parameter disables that behavior,
650				possibly causing your machine to run very slowly.
651	
652		disable_timer_pin_1 [X86]
653				Disable PIN 1 of APIC timer
654				Can be useful to work around chipset bugs.
655	
656		dmasound=	[HW,OSS] Sound subsystem buffers
657	
658		dma_debug=off	If the kernel is compiled with DMA_API_DEBUG support,
659				this option disables the debugging code at boot.
660	
661		dma_debug_entries=<number>
662				This option allows to tune the number of preallocated
663				entries for DMA-API debugging code. One entry is
664				required per DMA-API allocation. Use this if the
665				DMA-API debugging code disables itself because the
666				architectural default is too low.
667	
668		dma_debug_driver=<driver_name>
669				With this option the DMA-API debugging driver
670				filter feature can be enabled at boot time. Just
671				pass the driver to filter for as the parameter.
672				The filter can be disabled or changed to another
673				driver later using sysfs.
674	
675		dscc4.setup=	[NET]
676	
677		dtc3181e=	[HW,SCSI]
678	
679		dynamic_printk	Enables pr_debug()/dev_dbg() calls if
680				CONFIG_DYNAMIC_PRINTK_DEBUG has been enabled.
681				These can also be switched on/off via
682				<debugfs>/dynamic_printk/modules
683	
684		earlycon=	[KNL] Output early console device and options.
685			uart[8250],io,<addr>[,options]
686			uart[8250],mmio,<addr>[,options]
687				Start an early, polled-mode console on the 8250/16550
688				UART at the specified I/O port or MMIO address.
689				The options are the same as for ttyS, above.
690	
691		earlyprintk=	[X86,SH,BLACKFIN]
692				earlyprintk=vga
693				earlyprintk=serial[,ttySn[,baudrate]]
694				earlyprintk=ttySn[,baudrate]
695				earlyprintk=dbgp[debugController#]
696	
697				Append ",keep" to not disable it when the real console
698				takes over.
699	
700				Only vga or serial or usb debug port at a time.
701	
702				Currently only ttyS0 and ttyS1 are supported.
703	
704				Interaction with the standard serial driver is not
705				very good.
706	
707				The VGA output is eventually overwritten by the real
708				console.
709	
710		eata=		[HW,SCSI]
711	
712		edd=		[EDD]
713				Format: {"off" | "on" | "skip[mbr]"}
714	
715		eisa_irq_edge=	[PARISC,HW]
716				See header of drivers/parisc/eisa.c.
717	
718		elanfreq=	[X86-32]
719				See comment before function elanfreq_setup() in
720				arch/x86/kernel/cpu/cpufreq/elanfreq.c.
721	
722		elevator=	[IOSCHED]
723				Format: {"anticipatory" | "cfq" | "deadline" | "noop"}
724				See Documentation/block/as-iosched.txt and
725				Documentation/block/deadline-iosched.txt for details.
726	
727		elfcorehdr=	[IA64,PPC,SH,X86]
728				Specifies physical address of start of kernel core
729				image elf header. Generally kexec loader will
730				pass this option to capture kernel.
731				See Documentation/kdump/kdump.txt for details.
732	
733		enable_mtrr_cleanup [X86]
734				The kernel tries to adjust MTRR layout from continuous
735				to discrete, to make X server driver able to add WB
736				entry later. This parameter enables that.
737	
738		enable_timer_pin_1 [X86]
739				Enable PIN 1 of APIC timer
740				Can be useful to work around chipset bugs
741				(in particular on some ATI chipsets).
742				The kernel tries to set a reasonable default.
743	
744		enforcing	[SELINUX] Set initial enforcing status.
745				Format: {"0" | "1"}
746				See security/selinux/Kconfig help text.
747				0 -- permissive (log only, no denials).
748				1 -- enforcing (deny and log).
749				Default value is 0.
750				Value can be changed at runtime via /selinux/enforce.
751	
752		ether=		[HW,NET] Ethernet cards parameters
753				This option is obsoleted by the "netdev=" option, which
754				has equivalent usage. See its documentation for details.
755	
756		eurwdt=		[HW,WDT] Eurotech CPU-1220/1410 onboard watchdog.
757				Format: <io>[,<irq>]
758	
759		failslab=
760		fail_page_alloc=
761		fail_make_request=[KNL]
762				General fault injection mechanism.
763				Format: <interval>,<probability>,<space>,<times>
764				See also /Documentation/fault-injection/.
765	
766		fd_mcs=		[HW,SCSI]
767				See header of drivers/scsi/fd_mcs.c.
768	
769		fdomain=	[HW,SCSI]
770				See header of drivers/scsi/fdomain.c.
771	
772		floppy=		[HW]
773				See Documentation/blockdev/floppy.txt.
774	
775		force_pal_cache_flush
776				[IA-64] Avoid check_sal_cache_flush which may hang on
777				buggy SAL_CACHE_FLUSH implementations. Using this
778				parameter will force ia64_sal_cache_flush to call
779				ia64_pal_cache_flush instead of SAL_CACHE_FLUSH.
780	
781		ftrace=[tracer]
782				[FTRACE] will set and start the specified tracer
783				as early as possible in order to facilitate early
784				boot debugging.
785	
786		ftrace_dump_on_oops
787				[FTRACE] will dump the trace buffers on oops.
788	
789		ftrace_filter=[function-list]
790				[FTRACE] Limit the functions traced by the function
791				tracer at boot up. function-list is a comma separated
792				list of functions. This list can be changed at run
793				time by the set_ftrace_filter file in the debugfs
794				tracing directory. 
795	
796		ftrace_notrace=[function-list]
797				[FTRACE] Do not trace the functions specified in
798				function-list. This list can be changed at run time
799				by the set_ftrace_notrace file in the debugfs
800				tracing directory.
801	
802		ftrace_graph_filter=[function-list]
803				[FTRACE] Limit the top level callers functions traced
804				by the function graph tracer at boot up.
805				function-list is a comma separated list of functions
806				that can be changed at run time by the
807				set_graph_function file in the debugfs tracing directory.
808	
809		gamecon.map[2|3]=
810				[HW,JOY] Multisystem joystick and NES/SNES/PSX pad
811				support via parallel port (up to 5 devices per port)
812				Format: <port#>,<pad1>,<pad2>,<pad3>,<pad4>,<pad5>
813				See also Documentation/input/joystick-parport.txt
814	
815		gamma=		[HW,DRM]
816	
817		gart_fix_e820=  [X86_64] disable the fix e820 for K8 GART
818				Format: off | on
819				default: on
820	
821		gcov_persist=	[GCOV] When non-zero (default), profiling data for
822				kernel modules is saved and remains accessible via
823				debugfs, even when the module is unloaded/reloaded.
824				When zero, profiling data is discarded and associated
825				debugfs files are removed at module unload time.
826	
827		gdth=		[HW,SCSI]
828				See header of drivers/scsi/gdth.c.
829	
830		gpt		[EFI] Forces disk with valid GPT signature but
831				invalid Protective MBR to be treated as GPT.
832	
833		gvp11=		[HW,SCSI]
834	
835		hashdist=	[KNL,NUMA] Large hashes allocated during boot
836				are distributed across NUMA nodes.  Defaults on
837				for 64bit NUMA, off otherwise.
838				Format: 0 | 1 (for off | on)
839	
840		hcl=		[IA-64] SGI's Hardware Graph compatibility layer
841	
842		hd=		[EIDE] (E)IDE hard drive subsystem geometry
843				Format: <cyl>,<head>,<sect>
844	
845		highmem=nn[KMG]	[KNL,BOOT] forces the highmem zone to have an exact
846				size of <nn>. This works even on boxes that have no
847				highmem otherwise. This also works to reduce highmem
848				size on bigger boxes.
849	
850		highres=	[KNL] Enable/disable high resolution timer mode.
851				Valid parameters: "on", "off"
852				Default: "on"
853	
854		hisax=		[HW,ISDN]
855				See Documentation/isdn/README.HiSax.
856	
857		hlt		[BUGS=ARM,SH]
858	
859		hpet=		[X86-32,HPET] option to control HPET usage
860				Format: { enable (default) | disable | force |
861					verbose }
862				disable: disable HPET and use PIT instead
863				force: allow force enabled of undocumented chips (ICH4,
864					VIA, nVidia)
865				verbose: show contents of HPET registers during setup
866	
867		hugepages=	[HW,X86-32,IA-64] HugeTLB pages to allocate at boot.
868		hugepagesz=	[HW,IA-64,PPC,X86-64] The size of the HugeTLB pages.
869				On x86-64 and powerpc, this option can be specified
870				multiple times interleaved with hugepages= to reserve
871				huge pages of different sizes. Valid pages sizes on
872				x86-64 are 2M (when the CPU supports "pse") and 1G
873				(when the CPU supports the "pdpe1gb" cpuinfo flag)
874				Note that 1GB pages can only be allocated at boot time
875				using hugepages= and not freed afterwards.
876	
877		hvc_iucv=	[S390] Number of z/VM IUCV hypervisor console (HVC)
878				       terminal devices. Valid values: 0..8
879		hvc_iucv_allow=	[S390] Comma-separated list of z/VM user IDs.
880				       If specified, z/VM IUCV HVC accepts connections
881				       from listed z/VM user IDs only.
882	
883		i2c_bus=	[HW] Override the default board specific I2C bus speed
884				     or register an additional I2C bus that is not
885				     registered from board initialization code.
886				     Format:
887				     <bus_id>,<clkrate>
888	
889		i8042.debug	[HW] Toggle i8042 debug mode
890		i8042.direct	[HW] Put keyboard port into non-translated mode
891		i8042.dumbkbd	[HW] Pretend that controller can only read data from
892				     keyboard and cannot control its state
893				     (Don't attempt to blink the leds)
894		i8042.noaux	[HW] Don't check for auxiliary (== mouse) port
895		i8042.nokbd	[HW] Don't check/create keyboard port
896		i8042.noloop	[HW] Disable the AUX Loopback command while probing
897				     for the AUX port
898		i8042.nomux	[HW] Don't check presence of an active multiplexing
899				     controller
900		i8042.nopnp	[HW] Don't use ACPIPnP / PnPBIOS to discover KBD/AUX
901				     controllers
902		i8042.panicblink=
903				[HW] Frequency with which keyboard LEDs should blink
904				     when kernel panics (default is 0.5 sec)
905		i8042.reset	[HW] Reset the controller during init and cleanup
906		i8042.unlock	[HW] Unlock (ignore) the keylock
907	
908		i810=		[HW,DRM]
909	
910		i8k.ignore_dmi	[HW] Continue probing hardware even if DMI data
911				indicates that the driver is running on unsupported
912				hardware.
913		i8k.force	[HW] Activate i8k driver even if SMM BIOS signature
914				does not match list of supported models.
915		i8k.power_status
916				[HW] Report power status in /proc/i8k
917				(disabled by default)
918		i8k.restricted	[HW] Allow controlling fans only if SYS_ADMIN
919				capability is set.
920	
921		ibmmcascsi=	[HW,MCA,SCSI] IBM MicroChannel SCSI adapter
922				See Documentation/mca.txt.
923	
924		icn=		[HW,ISDN]
925				Format: <io>[,<membase>[,<icn_id>[,<icn_id2>]]]
926	
927		ide-core.nodma=	[HW] (E)IDE subsystem
928				Format: =0.0 to prevent dma on hda, =0.1 hdb =1.0 hdc
929				.vlb_clock .pci_clock .noflush .nohpa .noprobe .nowerr
930				.cdrom .chs .ignore_cable are additional options
931				See Documentation/ide/ide.txt.
932	
933		ide-pci-generic.all-generic-ide [HW] (E)IDE subsystem
934				Claim all unknown PCI IDE storage controllers.
935	
936		idle=		[X86]
937				Format: idle=poll, idle=mwait, idle=halt, idle=nomwait
938				Poll forces a polling idle loop that can slightly
939				improve the performance of waking up a idle CPU, but
940				will use a lot of power and make the system run hot.
941				Not recommended.
942				idle=mwait: On systems which support MONITOR/MWAIT but
943				the kernel chose to not use it because it doesn't save
944				as much power as a normal idle loop, use the
945				MONITOR/MWAIT idle loop anyways. Performance should be
946				the same as idle=poll.
947				idle=halt: Halt is forced to be used for CPU idle.
948				In such case C2/C3 won't be used again.
949				idle=nomwait: Disable mwait for CPU C-states
950	
951		ignore_loglevel	[KNL]
952				Ignore loglevel setting - this will print /all/
953				kernel messages to the console. Useful for debugging.
954	
955		ihash_entries=	[KNL]
956				Set number of hash buckets for inode cache.
957	
958		ima_audit=	[IMA]
959				Format: { "0" | "1" }
960				0 -- integrity auditing messages. (Default)
961				1 -- enable informational integrity auditing messages.
962	
963		ima_hash=	[IMA]
964				Format: { "sha1" | "md5" }
965				default: "sha1"
966	
967		ima_tcb		[IMA]
968				Load a policy which meets the needs of the Trusted
969				Computing Base.  This means IMA will measure all
970				programs exec'd, files mmap'd for exec, and all files
971				opened for read by uid=0.
972	
973		in2000=		[HW,SCSI]
974				See header of drivers/scsi/in2000.c.
975	
976		init=		[KNL]
977				Format: <full_path>
978				Run specified binary instead of /sbin/init as init
979				process.
980	
981		initcall_debug	[KNL] Trace initcalls as they are executed.  Useful
982				for working out where the kernel is dying during
983				startup.
984	
985		initrd=		[BOOT] Specify the location of the initial ramdisk
986	
987		inport.irq=	[HW] Inport (ATI XL and Microsoft) busmouse driver
988				Format: <irq>
989	
990		intel_iommu=	[DMAR] Intel IOMMU driver (DMAR) option
991			on
992				Enable intel iommu driver.
993			off
994				Disable intel iommu driver.
995			igfx_off [Default Off]
996				By default, gfx is mapped as normal device. If a gfx
997				device has a dedicated DMAR unit, the DMAR unit is
998				bypassed by not enabling DMAR with this option. In
999				this case, gfx device will use physical address for
1000				DMA.
1001			forcedac [x86_64]
1002				With this option iommu will not optimize to look
1003				for io virtual address below 32 bit forcing dual
1004				address cycle on pci bus for cards supporting greater
1005				than 32 bit addressing. The default is to look
1006				for translation below 32 bit and if not available
1007				then look in the higher range.
1008			strict [Default Off]
1009				With this option on every unmap_single operation will
1010				result in a hardware IOTLB flush operation as opposed
1011				to batching them for performance.
1012	
1013		inttest=	[IA64]
1014	
1015		iomem=		Disable strict checking of access to MMIO memory
1016			strict	regions from userspace.
1017			relaxed
1018	
1019		iommu=		[x86]
1020			off
1021			force
1022			noforce
1023			biomerge
1024			panic
1025			nopanic
1026			merge
1027			nomerge
1028			forcesac
1029			soft
1030			pt	[x86, IA64]
1031	
1032		io7=		[HW] IO7 for Marvel based alpha systems
1033				See comment before marvel_specify_io7 in
1034				arch/alpha/kernel/core_marvel.c.
1035	
1036		io_delay=	[X86] I/O delay method
1037			0x80
1038				Standard port 0x80 based delay
1039			0xed
1040				Alternate port 0xed based delay (needed on some systems)
1041			udelay
1042				Simple two microseconds delay
1043			none
1044				No delay
1045	
1046		ip=		[IP_PNP]
1047				See Documentation/filesystems/nfs/nfsroot.txt.
1048	
1049		ip2=		[HW] Set IO/IRQ pairs for up to 4 IntelliPort boards
1050				See comment before ip2_setup() in
1051				drivers/char/ip2/ip2base.c.
1052	
1053		ips=		[HW,SCSI] Adaptec / IBM ServeRAID controller
1054				See header of drivers/scsi/ips.c.
1055	
1056		irqfixup	[HW]
1057				When an interrupt is not handled search all handlers
1058				for it. Intended to get systems with badly broken
1059				firmware running.
1060	
1061		irqpoll		[HW]
1062				When an interrupt is not handled search all handlers
1063				for it. Also check all handlers each timer
1064				interrupt. Intended to get systems with badly broken
1065				firmware running.
1066	
1067		isapnp=		[ISAPNP]
1068				Format: <RDP>,<reset>,<pci_scan>,<verbosity>
1069	
1070		isolcpus=	[KNL,SMP] Isolate CPUs from the general scheduler.
1071				Format:
1072				<cpu number>,...,<cpu number>
1073				or
1074				<cpu number>-<cpu number>
1075				(must be a positive range in ascending order)
1076				or a mixture
1077				<cpu number>,...,<cpu number>-<cpu number>
1078	
1079				This option can be used to specify one or more CPUs
1080				to isolate from the general SMP balancing and scheduling
1081				algorithms. You can move a process onto or off an
1082				"isolated" CPU via the CPU affinity syscalls or cpuset.
1083				<cpu number> begins at 0 and the maximum value is
1084				"number of CPUs in system - 1".
1085	
1086				This option is the preferred way to isolate CPUs. The
1087				alternative -- manually setting the CPU mask of all
1088				tasks in the system -- can cause problems and
1089				suboptimal load balancer performance.
1090	
1091		iucv=		[HW,NET]
1092	
1093		js=		[HW,JOY] Analog joystick
1094				See Documentation/input/joystick.txt.
1095	
1096		keepinitrd	[HW,ARM]
1097	
1098		kernelcore=nn[KMG]	[KNL,X86,IA-64,PPC] This parameter
1099				specifies the amount of memory usable by the kernel
1100				for non-movable allocations.  The requested amount is
1101				spread evenly throughout all nodes in the system. The
1102				remaining memory in each node is used for Movable
1103				pages. In the event, a node is too small to have both
1104				kernelcore and Movable pages, kernelcore pages will
1105				take priority and other nodes will have a larger number
1106				of kernelcore pages.  The Movable zone is used for the
1107				allocation of pages that may be reclaimed or moved
1108				by the page migration subsystem.  This means that
1109				HugeTLB pages may not be allocated from this zone.
1110				Note that allocations like PTEs-from-HighMem still
1111				use the HighMem zone if it exists, and the Normal
1112				zone if it does not.
1113	
1114		kgdboc=		[HW] kgdb over consoles.
1115				Requires a tty driver that supports console polling.
1116				(only serial supported for now)
1117				Format: <serial_device>[,baud]
1118	
1119		kmac=		[MIPS] korina ethernet MAC address.
1120				Configure the RouterBoard 532 series on-chip
1121				Ethernet adapter MAC address.
1122	
1123		kmemleak=	[KNL] Boot-time kmemleak enable/disable
1124				Valid arguments: on, off
1125				Default: on
1126	
1127		kstack=N	[X86] Print N words from the kernel stack
1128				in oops dumps.
1129	
1130		kvm.ignore_msrs=[KVM] Ignore guest accesses to unhandled MSRs.
1131				Default is 0 (don't ignore, but inject #GP)
1132	
1133		kvm.oos_shadow=	[KVM] Disable out-of-sync shadow paging.
1134				Default is 1 (enabled)
1135	
1136		kvm-amd.nested=	[KVM,AMD] Allow nested virtualization in KVM/SVM.
1137				Default is 0 (off)
1138	
1139		kvm-amd.npt=	[KVM,AMD] Disable nested paging (virtualized MMU)
1140				for all guests.
1141				Default is 1 (enabled) if in 64bit or 32bit-PAE mode
1142	
1143		kvm-intel.bypass_guest_pf=
1144				[KVM,Intel] Disables bypassing of guest page faults
1145				on Intel chips. Default is 1 (enabled)
1146	
1147		kvm-intel.ept=	[KVM,Intel] Disable extended page tables
1148				(virtualized MMU) support on capable Intel chips.
1149				Default is 1 (enabled)
1150	
1151		kvm-intel.emulate_invalid_guest_state=
1152				[KVM,Intel] Enable emulation of invalid guest states
1153				Default is 0 (disabled)
1154	
1155		kvm-intel.flexpriority=
1156				[KVM,Intel] Disable FlexPriority feature (TPR shadow).
1157				Default is 1 (enabled)
1158	
1159		kvm-intel.unrestricted_guest=
1160				[KVM,Intel] Disable unrestricted guest feature
1161				(virtualized real and unpaged mode) on capable
1162				Intel chips. Default is 1 (enabled)
1163	
1164		kvm-intel.vpid=	[KVM,Intel] Disable Virtual Processor Identification
1165				feature (tagged TLBs) on capable Intel chips.
1166				Default is 1 (enabled)
1167	
1168		l2cr=		[PPC]
1169	
1170		l3cr=		[PPC]
1171	
1172		lapic		[X86-32,APIC] Enable the local APIC even if BIOS
1173				disabled it.
1174	
1175		lapic_timer_c2_ok	[X86,APIC] trust the local apic timer
1176				in C2 power state.
1177	
1178		libata.dma=	[LIBATA] DMA control
1179				libata.dma=0	  Disable all PATA and SATA DMA
1180				libata.dma=1	  PATA and SATA Disk DMA only
1181				libata.dma=2	  ATAPI (CDROM) DMA only
1182				libata.dma=4	  Compact Flash DMA only 
1183				Combinations also work, so libata.dma=3 enables DMA
1184				for disks and CDROMs, but not CFs.
1185		
1186		libata.ignore_hpa=	[LIBATA] Ignore HPA limit
1187				libata.ignore_hpa=0	  keep BIOS limits (default)
1188				libata.ignore_hpa=1	  ignore limits, using full disk
1189	
1190		libata.noacpi	[LIBATA] Disables use of ACPI in libata suspend/resume
1191				when set.
1192				Format: <int>
1193	
1194		libata.force=	[LIBATA] Force configurations.  The format is comma
1195				separated list of "[ID:]VAL" where ID is
1196				PORT[:DEVICE].  PORT and DEVICE are decimal numbers
1197				matching port, link or device.  Basically, it matches
1198				the ATA ID string printed on console by libata.  If
1199				the whole ID part is omitted, the last PORT and DEVICE
1200				values are used.  If ID hasn't been specified yet, the
1201				configuration applies to all ports, links and devices.
1202	
1203				If only DEVICE is omitted, the parameter applies to
1204				the port and all links and devices behind it.  DEVICE
1205				number of 0 either selects the first device or the
1206				first fan-out link behind PMP device.  It does not
1207				select the host link.  DEVICE number of 15 selects the
1208				host link and device attached to it.
1209	
1210				The VAL specifies the configuration to force.  As long
1211				as there's no ambiguity shortcut notation is allowed.
1212				For example, both 1.5 and 1.5G would work for 1.5Gbps.
1213				The following configurations can be forced.
1214	
1215				* Cable type: 40c, 80c, short40c, unk, ign or sata.
1216				  Any ID with matching PORT is used.
1217	
1218				* SATA link speed limit: 1.5Gbps or 3.0Gbps.
1219	
1220				* Transfer mode: pio[0-7], mwdma[0-4] and udma[0-7].
1221				  udma[/][16,25,33,44,66,100,133] notation is also
1222				  allowed.
1223	
1224				* [no]ncq: Turn on or off NCQ.
1225	
1226				* nohrst, nosrst, norst: suppress hard, soft
1227	                          and both resets.
1228	
1229				If there are multiple matching configurations changing
1230				the same attribute, the last one is used.
1231	
1232		lmb=debug	[KNL] Enable lmb debug messages.
1233	
1234		load_ramdisk=	[RAM] List of ramdisks to load from floppy
1235				See Documentation/blockdev/ramdisk.txt.
1236	
1237		lockd.nlm_grace_period=P  [NFS] Assign grace period.
1238				Format: <integer>
1239	
1240		lockd.nlm_tcpport=N	[NFS] Assign TCP port.
1241				Format: <integer>
1242	
1243		lockd.nlm_timeout=T	[NFS] Assign timeout value.
1244				Format: <integer>
1245	
1246		lockd.nlm_udpport=M	[NFS] Assign UDP port.
1247				Format: <integer>
1248	
1249		logibm.irq=	[HW,MOUSE] Logitech Bus Mouse Driver
1250				Format: <irq>
1251	
1252		loglevel=	All Kernel Messages with a loglevel smaller than the
1253				console loglevel will be printed to the console. It can
1254				also be changed with klogd or other programs. The
1255				loglevels are defined as follows:
1256	
1257				0 (KERN_EMERG)		system is unusable
1258				1 (KERN_ALERT)		action must be taken immediately
1259				2 (KERN_CRIT)		critical conditions
1260				3 (KERN_ERR)		error conditions
1261				4 (KERN_WARNING)	warning conditions
1262				5 (KERN_NOTICE)		normal but significant condition
1263				6 (KERN_INFO)		informational
1264				7 (KERN_DEBUG)		debug-level messages
1265	
1266		log_buf_len=n	Sets the size of the printk ring buffer, in bytes.
1267				Format: { n | nk | nM }
1268				n must be a power of two.  The default size
1269				is set in the kernel config file.
1270	
1271		logo.nologo	[FB] Disables display of the built-in Linux logo.
1272				This may be used to provide more screen space for
1273				kernel log messages and is useful when debugging
1274				kernel boot problems.
1275	
1276		lp=0		[LP]	Specify parallel ports to use, e.g,
1277		lp=port[,port...]	lp=none,parport0 (lp0 not configured, lp1 uses
1278		lp=reset		first parallel port). 'lp=0' disables the
1279		lp=auto			printer driver. 'lp=reset' (which can be
1280					specified in addition to the ports) causes
1281					attached printers to be reset. Using
1282					lp=port1,port2,... specifies the parallel ports
1283					to associate lp devices with, starting with
1284					lp0. A port specification may be 'none' to skip
1285					that lp device, or a parport name such as
1286					'parport0'. Specifying 'lp=auto' instead of a
1287					port specification list means that device IDs
1288					from each port should be examined, to see if
1289					an IEEE 1284-compliant printer is attached; if
1290					so, the driver will manage that printer.
1291					See also header of drivers/char/lp.c.
1292	
1293		lpj=n		[KNL]
1294				Sets loops_per_jiffy to given constant, thus avoiding
1295				time-consuming boot-time autodetection (up to 250 ms per
1296				CPU). 0 enables autodetection (default). To determine
1297				the correct value for your kernel, boot with normal
1298				autodetection and see what value is printed. Note that
1299				on SMP systems the preset will be applied to all CPUs,
1300				which is likely to cause problems if your CPUs need
1301				significantly divergent settings. An incorrect value
1302				will cause delays in the kernel to be wrong, leading to
1303				unpredictable I/O errors and other breakage. Although
1304				unlikely, in the extreme case this might damage your
1305				hardware.
1306	
1307		ltpc=		[NET]
1308				Format: <io>,<irq>,<dma>
1309	
1310		mac5380=	[HW,SCSI] Format:
1311				<can_queue>,<cmd_per_lun>,<sg_tablesize>,<hostid>,<use_tags>
1312	
1313		machvec=	[IA64] Force the use of a particular machine-vector
1314				(machvec) in a generic kernel.
1315				Example: machvec=hpzx1_swiotlb
1316	
1317		machtype=	[Loongson] Share the same kernel image file between different
1318				 yeeloong laptop.
1319				Example: machtype=lemote-yeeloong-2f-7inch
1320	
1321		max_addr=nn[KMG]	[KNL,BOOT,ia64] All physical memory greater
1322				than or equal to this physical address is ignored.
1323	
1324		maxcpus=	[SMP] Maximum number of processors that	an SMP kernel
1325				should make use of.  maxcpus=n : n >= 0 limits the
1326				kernel to using 'n' processors.  n=0 is a special case,
1327				it is equivalent to "nosmp", which also disables
1328				the IO APIC.
1329	
1330		max_loop=	[LOOP] Maximum number of loopback devices that can
1331				be mounted
1332				Format: <1-256>
1333	
1334		max_luns=	[SCSI] Maximum number of LUNs to probe.
1335				Should be between 1 and 2^32-1.
1336	
1337		max_report_luns=
1338				[SCSI] Maximum number of LUNs received.
1339				Should be between 1 and 16384.
1340	
1341		mcatest=	[IA-64]
1342	
1343		mce		[X86-32] Machine Check Exception
1344	
1345		mce=option	[X86-64] See Documentation/x86/x86_64/boot-options.txt
1346	
1347		md=		[HW] RAID subsystems devices and level
1348				See Documentation/md.txt.
1349	
1350		mdacon=		[MDA]
1351				Format: <first>,<last>
1352				Specifies range of consoles to be captured by the MDA.
1353	
1354		mem=nn[KMG]	[KNL,BOOT] Force usage of a specific amount of memory
1355				Amount of memory to be used when the kernel is not able
1356				to see the whole system memory or for test.
1357				[X86-32] Use together with memmap= to avoid physical
1358				address space collisions. Without memmap= PCI devices
1359				could be placed at addresses belonging to unused RAM.
1360	
1361		mem=nopentium	[BUGS=X86-32] Disable usage of 4MB pages for kernel
1362				memory.
1363	
1364		memchunk=nn[KMG]
1365				[KNL,SH] Allow user to override the default size for
1366				per-device physically contiguous DMA buffers.
1367	
1368		memmap=exactmap	[KNL,X86] Enable setting of an exact
1369				E820 memory map, as specified by the user.
1370				Such memmap=exactmap lines can be constructed based on
1371				BIOS output or other requirements. See the memmap=nn@ss
1372				option description.
1373	
1374		memmap=nn[KMG]@ss[KMG]
1375				[KNL] Force usage of a specific region of memory
1376				Region of memory to be used, from ss to ss+nn.
1377	
1378		memmap=nn[KMG]#ss[KMG]
1379				[KNL,ACPI] Mark specific memory as ACPI data.
1380				Region of memory to be used, from ss to ss+nn.
1381	
1382		memmap=nn[KMG]$ss[KMG]
1383				[KNL,ACPI] Mark specific memory as reserved.
1384				Region of memory to be used, from ss to ss+nn.
1385				Example: Exclude memory from 0x18690000-0x1869ffff
1386				         memmap=64K$0x18690000
1387				         or
1388				         memmap=0x10000$0x18690000
1389	
1390		memory_corruption_check=0/1 [X86]
1391				Some BIOSes seem to corrupt the first 64k of
1392				memory when doing things like suspend/resume.
1393				Setting this option will scan the memory
1394				looking for corruption.  Enabling this will
1395				both detect corruption and prevent the kernel
1396				from using the memory being corrupted.
1397				However, its intended as a diagnostic tool; if
1398				repeatable BIOS-originated corruption always
1399				affects the same memory, you can use memmap=
1400				to prevent the kernel from using that memory.
1401	
1402		memory_corruption_check_size=size [X86]
1403				By default it checks for corruption in the low
1404				64k, making this memory unavailable for normal
1405				use.  Use this parameter to scan for
1406				corruption in more or less memory.
1407	
1408		memory_corruption_check_period=seconds [X86]
1409				By default it checks for corruption every 60
1410				seconds.  Use this parameter to check at some
1411				other rate.  0 disables periodic checking.
1412	
1413		memtest=	[KNL,X86] Enable memtest
1414				Format: <integer>
1415				default : 0 <disable>
1416				Specifies the number of memtest passes to be
1417				performed. Each pass selects another test
1418				pattern from a given set of patterns. Memtest
1419				fills the memory with this pattern, validates
1420				memory contents and reserves bad memory
1421				regions that are detected.
1422	
1423		meye.*=		[HW] Set MotionEye Camera parameters
1424				See Documentation/video4linux/meye.txt.
1425	
1426		mfgpt_irq=	[IA-32] Specify the IRQ to use for the
1427				Multi-Function General Purpose Timers on AMD Geode
1428				platforms.
1429	
1430		mfgptfix	[X86-32] Fix MFGPT timers on AMD Geode platforms when
1431				the BIOS has incorrectly applied a workaround. TinyBIOS
1432				version 0.98 is known to be affected, 0.99 fixes the
1433				problem by letting the user disable the workaround.
1434	
1435		mga=		[HW,DRM]
1436	
1437		min_addr=nn[KMG]	[KNL,BOOT,ia64] All physical memory below this
1438				physical address is ignored.
1439	
1440		mini2440=	[ARM,HW,KNL]
1441				Format:[0..2][b][c][t]
1442				Default: "0tb"
1443				MINI2440 configuration specification:
1444				0 - The attached screen is the 3.5" TFT
1445				1 - The attached screen is the 7" TFT
1446				2 - The VGA Shield is attached (1024x768)
1447				Leaving out the screen size parameter will not load
1448				the TFT driver, and the framebuffer will be left
1449				unconfigured.
1450				b - Enable backlight. The TFT backlight pin will be
1451				linked to the kernel VESA blanking code and a GPIO
1452				LED. This parameter is not necessary when using the
1453				VGA shield.
1454				c - Enable the s3c camera interface.
1455				t - Reserved for enabling touchscreen support. The
1456				touchscreen support is not enabled in the mainstream
1457				kernel as of 2.6.30, a preliminary port can be found
1458				in the "bleeding edge" mini2440 support kernel at
1459				http://repo.or.cz/w/linux-2.6/mini2440.git
1460	
1461		mminit_loglevel=
1462				[KNL] When CONFIG_DEBUG_MEMORY_INIT is set, this
1463				parameter allows control of the logging verbosity for
1464				the additional memory initialisation checks. A value
1465				of 0 disables mminit logging and a level of 4 will
1466				log everything. Information is printed at KERN_DEBUG
1467				so loglevel=8 may also need to be specified.
1468	
1469		mousedev.tap_time=
1470				[MOUSE] Maximum time between finger touching and
1471				leaving touchpad surface for touch to be considered
1472				a tap and be reported as a left button click (for
1473				touchpads working in absolute mode only).
1474				Format: <msecs>
1475		mousedev.xres=	[MOUSE] Horizontal screen resolution, used for devices
1476				reporting absolute coordinates, such as tablets
1477		mousedev.yres=	[MOUSE] Vertical screen resolution, used for devices
1478				reporting absolute coordinates, such as tablets
1479	
1480		movablecore=nn[KMG]	[KNL,X86,IA-64,PPC] This parameter
1481				is similar to kernelcore except it specifies the
1482				amount of memory used for migratable allocations.
1483				If both kernelcore and movablecore is specified,
1484				then kernelcore will be at *least* the specified
1485				value but may be more. If movablecore on its own
1486				is specified, the administrator must be careful
1487				that the amount of memory usable for all allocations
1488				is not too small.
1489	
1490		mpu401=		[HW,OSS]
1491				Format: <io>,<irq>
1492	
1493		MTD_Partition=	[MTD]
1494				Format: <name>,<region-number>,<size>,<offset>
1495	
1496		MTD_Region=	[MTD] Format:
1497				<name>,<region-number>[,<base>,<size>,<buswidth>,<altbuswidth>]
1498	
1499		mtdparts=	[MTD]
1500				See drivers/mtd/cmdlinepart.c.
1501	
1502		onenand.bdry=	[HW,MTD] Flex-OneNAND Boundary Configuration
1503	
1504				Format: [die0_boundary][,die0_lock][,die1_boundary][,die1_lock]
1505	
1506				boundary - index of last SLC block on Flex-OneNAND.
1507					   The remaining blocks are configured as MLC blocks.
1508				lock	 - Configure if Flex-OneNAND boundary should be locked.
1509					   Once locked, the boundary cannot be changed.
1510					   1 indicates lock status, 0 indicates unlock status.
1511	
1512		mtdset=		[ARM]
1513				ARM/S3C2412 JIVE boot control
1514	
1515				See arch/arm/mach-s3c2412/mach-jive.c
1516	
1517		mtouchusb.raw_coordinates=
1518				[HW] Make the MicroTouch USB driver use raw coordinates
1519				('y', default) or cooked coordinates ('n')
1520	
1521		mtrr_chunk_size=nn[KMG] [X86]
1522				used for mtrr cleanup. It is largest continuous chunk
1523				that could hold holes aka. UC entries.
1524	
1525		mtrr_gran_size=nn[KMG] [X86]
1526				Used for mtrr cleanup. It is granularity of mtrr block.
1527				Default is 1.
1528				Large value could prevent small alignment from
1529				using up MTRRs.
1530	
1531		mtrr_spare_reg_nr=n [X86]
1532				Format: <integer>
1533				Range: 0,7 : spare reg number
1534				Default : 1
1535				Used for mtrr cleanup. It is spare mtrr entries number.
1536				Set to 2 or more if your graphical card needs more.
1537	
1538		n2=		[NET] SDL Inc. RISCom/N2 synchronous serial card
1539	
1540		NCR_D700=	[HW,SCSI]
1541				See header of drivers/scsi/NCR_D700.c.
1542	
1543		ncr5380=	[HW,SCSI]
1544	
1545		ncr53c400=	[HW,SCSI]
1546	
1547		ncr53c400a=	[HW,SCSI]
1548	
1549		ncr53c406a=	[HW,SCSI]
1550	
1551		ncr53c8xx=	[HW,SCSI]
1552	
1553		netdev=		[NET] Network devices parameters
1554				Format: <irq>,<io>,<mem_start>,<mem_end>,<name>
1555				Note that mem_start is often overloaded to mean
1556				something different and driver-specific.
1557				This usage is only documented in each driver source
1558				file if at all.
1559	
1560		nf_conntrack.acct=
1561				[NETFILTER] Enable connection tracking flow accounting
1562				0 to disable accounting
1563				1 to enable accounting
1564				Default value depends on CONFIG_NF_CT_ACCT that is
1565				going to be removed in 2.6.29.
1566	
1567		nfsaddrs=	[NFS]
1568				See Documentation/filesystems/nfs/nfsroot.txt.
1569	
1570		nfsroot=	[NFS] nfs root filesystem for disk-less boxes.
1571				See Documentation/filesystems/nfs/nfsroot.txt.
1572	
1573		nfs.callback_tcpport=
1574				[NFS] set the TCP port on which the NFSv4 callback
1575				channel should listen.
1576	
1577		nfs.cache_getent=
1578				[NFS] sets the pathname to the program which is used
1579				to update the NFS client cache entries.
1580	
1581		nfs.cache_getent_timeout=
1582				[NFS] sets the timeout after which an attempt to
1583				update a cache entry is deemed to have failed.
1584	
1585		nfs.idmap_cache_timeout=
1586				[NFS] set the maximum lifetime for idmapper cache
1587				entries.
1588	
1589		nfs.enable_ino64=
1590				[NFS] enable 64-bit inode numbers.
1591				If zero, the NFS client will fake up a 32-bit inode
1592				number for the readdir() and stat() syscalls instead
1593				of returning the full 64-bit number.
1594				The default is to return 64-bit inode numbers.
1595	
1596		nmi_debug=	[KNL,AVR32,SH] Specify one or more actions to take
1597				when a NMI is triggered.
1598				Format: [state][,regs][,debounce][,die]
1599	
1600		nmi_watchdog=	[KNL,BUGS=X86] Debugging features for SMP kernels
1601				Format: [panic,][num]
1602				Valid num: 0,1,2
1603				0 - turn nmi_watchdog off
1604				1 - use the IO-APIC timer for the NMI watchdog
1605				2 - use the local APIC for the NMI watchdog using
1606				a performance counter. Note: This will use one
1607				performance counter and the local APIC's performance
1608				vector.
1609				When panic is specified, panic when an NMI watchdog
1610				timeout occurs.
1611				This is useful when you use a panic=... timeout and
1612				need the box quickly up again.
1613				Instead of 1 and 2 it is possible to use the following
1614				symbolic names: lapic and ioapic
1615				Example: nmi_watchdog=2 or nmi_watchdog=panic,lapic
1616	
1617		netpoll.carrier_timeout=
1618				[NET] Specifies amount of time (in seconds) that
1619				netpoll should wait for a carrier. By default netpoll
1620				waits 4 seconds.
1621	
1622		no387		[BUGS=X86-32] Tells the kernel to use the 387 maths
1623				emulation library even if a 387 maths coprocessor
1624				is present.
1625	
1626		no_console_suspend
1627				[HW] Never suspend the console
1628				Disable suspending of consoles during suspend and
1629				hibernate operations.  Once disabled, debugging
1630				messages can reach various consoles while the rest
1631				of the system is being put to sleep (ie, while
1632				debugging driver suspend/resume hooks).  This may
1633				not work reliably with all consoles, but is known
1634				to work with serial and VGA consoles.
1635	
1636		noaliencache	[MM, NUMA, SLAB] Disables the allocation of alien
1637				caches in the slab allocator.  Saves per-node memory,
1638				but will impact performance.
1639	
1640		noalign		[KNL,ARM]
1641	
1642		noapic		[SMP,APIC] Tells the kernel to not make use of any
1643				IOAPICs that may be present in the system.
1644	
1645		nobats		[PPC] Do not use BATs for mapping kernel lowmem
1646				on "Classic" PPC cores.
1647	
1648		nocache		[ARM]
1649	
1650		noclflush	[BUGS=X86] Don't use the CLFLUSH instruction
1651	
1652		nodelayacct	[KNL] Disable per-task delay accounting
1653	
1654		nodisconnect	[HW,SCSI,M68K] Disables SCSI disconnects.
1655	
1656		nodsp		[SH] Disable hardware DSP at boot time.
1657	
1658		noefi		[X86] Disable EFI runtime services support.
1659	
1660		noexec		[IA-64]
1661	
1662		noexec		[X86]
1663				On X86-32 available only on PAE configured kernels.
1664				noexec=on: enable non-executable mappings (default)
1665				noexec=off: disable non-executable mappings
1666	
1667		noexec32	[X86-64]
1668				This affects only 32-bit executables.
1669				noexec32=on: enable non-executable mappings (default)
1670					read doesn't imply executable mappings
1671				noexec32=off: disable non-executable mappings
1672					read implies executable mappings
1673	
1674		nofpu		[SH] Disable hardware FPU at boot time.
1675	
1676		nofxsr		[BUGS=X86-32] Disables x86 floating point extended
1677				register save and restore. The kernel will only save
1678				legacy floating-point registers on task switch.
1679	
1680		noxsave		[BUGS=X86] Disables x86 extended register state save
1681				and restore using xsave. The kernel will fallback to
1682				enabling legacy floating-point and sse state.
1683	
1684		nohlt		[BUGS=ARM,SH] Tells the kernel that the sleep(SH) or
1685				wfi(ARM) instruction doesn't work correctly and not to
1686				use it. This is also useful when using JTAG debugger.
1687	
1688		no-hlt		[BUGS=X86-32] Tells the kernel that the hlt
1689				instruction doesn't work correctly and not to
1690				use it.
1691	
1692		no_file_caps	Tells the kernel not to honor file capabilities.  The
1693				only way then for a file to be executed with privilege
1694				is to be setuid root or executed by root.
1695	
1696		nohalt		[IA-64] Tells the kernel not to use the power saving
1697				function PAL_HALT_LIGHT when idle. This increases
1698				power-consumption. On the positive side, it reduces
1699				interrupt wake-up latency, which may improve performance
1700				in certain environments such as networked servers or
1701				real-time systems.
1702	
1703		nohz=		[KNL] Boottime enable/disable dynamic ticks
1704				Valid arguments: on, off
1705				Default: on
1706	
1707		noiotrap	[SH] Disables trapped I/O port accesses.
1708	
1709		noirqdebug	[X86-32] Disables the code which attempts to detect and
1710				disable unhandled interrupt sources.
1711	
1712		no_timer_check	[X86,APIC] Disables the code which tests for
1713				broken timer IRQ sources.
1714	
1715		noisapnp	[ISAPNP] Disables ISA PnP code.
1716	
1717		noinitrd	[RAM] Tells the kernel not to load any configured
1718				initial RAM disk.
1719	
1720		nointremap	[X86-64, Intel-IOMMU] Do not enable interrupt
1721				remapping.
1722	
1723		nointroute	[IA-64]
1724	
1725		nojitter	[IA64] Disables jitter checking for ITC timers.
1726	
1727		nolapic		[X86-32,APIC] Do not enable or use the local APIC.
1728	
1729		nolapic_timer	[X86-32,APIC] Do not use the local APIC timer.
1730	
1731		noltlbs		[PPC] Do not use large page/tlb entries for kernel
1732				lowmem mapping on PPC40x.
1733	
1734		nomca		[IA-64] Disable machine check abort handling
1735	
1736		nomce		[X86-32] Machine Check Exception
1737	
1738		nomfgpt		[X86-32] Disable Multi-Function General Purpose
1739				Timer usage (for AMD Geode machines).
1740	
1741		norandmaps	Don't use address space randomization.  Equivalent to
1742				echo 0 > /proc/sys/kernel/randomize_va_space
1743	
1744		noreplace-paravirt	[X86-32,PV_OPS] Don't patch paravirt_ops
1745	
1746		noreplace-smp	[X86-32,SMP] Don't replace SMP instructions
1747				with UP alternatives
1748	
1749		noresidual	[PPC] Don't use residual data on PReP machines.
1750	
1751		noresume	[SWSUSP] Disables resume and restores original swap
1752				space.
1753	
1754		no-scroll	[VGA] Disables scrollback.
1755				This is required for the Braillex ib80-piezo Braille
1756				reader made by F.H. Papenmeier (Germany).
1757	
1758		nosbagart	[IA-64]
1759	
1760		nosep		[BUGS=X86-32] Disables x86 SYSENTER/SYSEXIT support.
1761	
1762		nosmp		[SMP] Tells an SMP kernel to act as a UP kernel,
1763				and disable the IO APIC.  legacy for "maxcpus=0".
1764	
1765		nosoftlockup	[KNL] Disable the soft-lockup detector.
1766	
1767		noswapaccount	[KNL] Disable accounting of swap in memory resource
1768				controller. (See Documentation/cgroups/memory.txt)
1769	
1770		nosync		[HW,M68K] Disables sync negotiation for all devices.
1771	
1772		notsc		[BUGS=X86-32] Disable Time Stamp Counter
1773	
1774		nousb		[USB] Disable the USB subsystem
1775	
1776		nowb		[ARM]
1777	
1778		nox2apic	[X86-64,APIC] Do not enable x2APIC mode.
1779	
1780		nptcg=		[IA64] Override max number of concurrent global TLB
1781				purges which is reported from either PAL_VM_SUMMARY or
1782				SAL PALO.
1783	
1784		nr_uarts=	[SERIAL] maximum number of UARTs to be registered.
1785	
1786		numa_zonelist_order= [KNL, BOOT] Select zonelist order for NUMA.
1787				one of ['zone', 'node', 'default'] can be specified
1788				This can be set from sysctl after boot.
1789				See Documentation/sysctl/vm.txt for details.
1790	
1791		ohci1394_dma=early	[HW] enable debugging via the ohci1394 driver.
1792				See Documentation/debugging-via-ohci1394.txt for more
1793				info.
1794	
1795		olpc_ec_timeout= [OLPC] ms delay when issuing EC commands
1796				Rather than timing out after 20 ms if an EC
1797				command is not properly ACKed, override the length
1798				of the timeout.  We have interrupts disabled while
1799				waiting for the ACK, so if this is set too high
1800				interrupts *may* be lost!
1801	
1802		omap_mux=	[OMAP] Override bootloader pin multiplexing.
1803				Format: <mux_mode0.mode_name=value>...
1804				For example, to override I2C bus2:
1805				omap_mux=i2c2_scl.i2c2_scl=0x100,i2c2_sda.i2c2_sda=0x100
1806	
1807		opl3=		[HW,OSS]
1808				Format: <io>
1809	
1810		oprofile.timer=	[HW]
1811				Use timer interrupt instead of performance counters
1812	
1813		oprofile.cpu_type=	Force an oprofile cpu type
1814				This might be useful if you have an older oprofile
1815				userland or if you want common events.
1816				Format: { arch_perfmon }
1817				arch_perfmon: [X86] Force use of architectural
1818					perfmon on Intel CPUs instead of the
1819					CPU specific event set.
1820	
1821		osst=		[HW,SCSI] SCSI Tape Driver
1822				Format: <buffer_size>,<write_threshold>
1823				See also Documentation/scsi/st.txt.
1824	
1825		panic=		[KNL] Kernel behaviour on panic
1826				Format: <timeout>
1827	
1828		parkbd.port=	[HW] Parallel port number the keyboard adapter is
1829				connected to, default is 0.
1830				Format: <parport#>
1831		parkbd.mode=	[HW] Parallel port keyboard adapter mode of operation,
1832				0 for XT, 1 for AT (default is AT).
1833				Format: <mode>
1834	
1835		parport=	[HW,PPT] Specify parallel ports. 0 disables.
1836				Format: { 0 | auto | 0xBBB[,IRQ[,DMA]] }
1837				Use 'auto' to force the driver to use any
1838				IRQ/DMA settings detected (the default is to
1839				ignore detected IRQ/DMA settings because of
1840				possible conflicts). You can specify the base
1841				address, IRQ, and DMA settings; IRQ and DMA
1842				should be numbers, or 'auto' (for using detected
1843				settings on that particular port), or 'nofifo'
1844				(to avoid using a FIFO even if it is detected).
1845				Parallel ports are assigned in the order they
1846				are specified on the command line, starting
1847				with parport0.
1848	
1849		parport_init_mode=	[HW,PPT]
1850				Configure VIA parallel port to operate in
1851				a specific mode. This is necessary on Pegasos
1852				computer where firmware has no options for setting
1853				up parallel port mode and sets it to spp.
1854				Currently this function knows 686a and 8231 chips.
1855				Format: [spp|ps2|epp|ecp|ecpepp]
1856	
1857		pas2=		[HW,OSS] Format:
1858				<io>,<irq>,<dma>,<dma16>,<sb_io>,<sb_irq>,<sb_dma>,<sb_dma16>
1859	
1860		pas16=		[HW,SCSI]
1861				See header of drivers/scsi/pas16.c.
1862	
1863		pause_on_oops=
1864				Halt all CPUs after the first oops has been printed for
1865				the specified number of seconds.  This is to be used if
1866				your oopses keep scrolling off the screen.
1867	
1868		pcbit=		[HW,ISDN]
1869	
1870		pcd.		[PARIDE]
1871				See header of drivers/block/paride/pcd.c.
1872				See also Documentation/blockdev/paride.txt.
1873	
1874		pci=option[,option...]	[PCI] various PCI subsystem options:
1875			earlydump	[X86] dump PCI config space before the kernel
1876				        changes anything
1877			off		[X86] don't probe for the PCI bus
1878			bios		[X86-32] force use of PCI BIOS, don't access
1879					the hardware directly. Use this if your machine
1880					has a non-standard PCI host bridge.
1881			nobios		[X86-32] disallow use of PCI BIOS, only direct
1882					hardware access methods are allowed. Use this
1883					if you experience crashes upon bootup and you
1884					suspect they are caused by the BIOS.
1885			conf1		[X86] Force use of PCI Configuration
1886					Mechanism 1.
1887			conf2		[X86] Force use of PCI Configuration
1888					Mechanism 2.
1889			noaer		[PCIE] If the PCIEAER kernel config parameter is
1890					enabled, this kernel boot option can be used to
1891					disable the use of PCIE advanced error reporting.
1892			nodomains	[PCI] Disable support for multiple PCI
1893					root domains (aka PCI segments, in ACPI-speak).
1894			nommconf	[X86] Disable use of MMCONFIG for PCI
1895					Configuration
1896			check_enable_amd_mmconf [X86] check for and enable
1897					properly configured MMIO access to PCI
1898					config space on AMD family 10h CPU
1899			nomsi		[MSI] If the PCI_MSI kernel config parameter is
1900					enabled, this kernel boot option can be used to
1901					disable the use of MSI interrupts system-wide.
1902			noioapicquirk	[APIC] Disable all boot interrupt quirks.
1903					Safety option to keep boot IRQs enabled. This
1904					should never be necessary.
1905			ioapicreroute	[APIC] Enable rerouting of boot IRQs to the
1906					primary IO-APIC for bridges that cannot disable
1907					boot IRQs. This fixes a source of spurious IRQs
1908					when the system masks IRQs.
1909			noioapicreroute	[APIC] Disable workaround that uses the
1910					boot IRQ equivalent of an IRQ that connects to
1911					a chipset where boot IRQs cannot be disabled.
1912					The opposite of ioapicreroute.
1913			biosirq		[X86-32] Use PCI BIOS calls to get the interrupt
1914					routing table. These calls are known to be buggy
1915					on several machines and they hang the machine
1916					when used, but on other computers it's the only
1917					way to get the interrupt routing table. Try
1918					this option if the kernel is unable to allocate
1919					IRQs or discover secondary PCI buses on your
1920					motherboard.
1921			rom		[X86] Assign address space to expansion ROMs.
1922					Use with caution as certain devices share
1923					address decoders between ROMs and other
1924					resources.
1925			norom		[X86] Do not assign address space to
1926					expansion ROMs that do not already have
1927					BIOS assigned address ranges.
1928			irqmask=0xMMMM	[X86] Set a bit mask of IRQs allowed to be
1929					assigned automatically to PCI devices. You can
1930					make the kernel exclude IRQs of your ISA cards
1931					this way.
1932			pirqaddr=0xAAAAA	[X86] Specify the physical address
1933					of the PIRQ table (normally generated
1934					by the BIOS) if it is outside the
1935					F0000h-100000h range.
1936			lastbus=N	[X86] Scan all buses thru bus #N. Can be
1937					useful if the kernel is unable to find your
1938					secondary buses and you want to tell it
1939					explicitly which ones they are.
1940			assign-busses	[X86] Always assign all PCI bus
1941					numbers ourselves, overriding
1942					whatever the firmware may have done.
1943			usepirqmask	[X86] Honor the possible IRQ mask stored
1944					in the BIOS $PIR table. This is needed on
1945					some systems with broken BIOSes, notably
1946					some HP Pavilion N5400 and Omnibook XE3
1947					notebooks. This will have no effect if ACPI
1948					IRQ routing is enabled.
1949			noacpi		[X86] Do not use ACPI for IRQ routing
1950					or for PCI scanning.
1951			use_crs		[X86] Use _CRS for PCI resource
1952					allocation.
1953			routeirq	Do IRQ routing for all PCI devices.
1954					This is normally done in pci_enable_device(),
1955					so this option is a temporary workaround
1956					for broken drivers that don't call it.
1957			skip_isa_align	[X86] do not align io start addr, so can
1958					handle more pci cards
1959			firmware	[ARM] Do not re-enumerate the bus but instead
1960					just use the configuration from the
1961					bootloader. This is currently used on
1962					IXP2000 systems where the bus has to be
1963					configured a certain way for adjunct CPUs.
1964			noearly		[X86] Don't do any early type 1 scanning.
1965					This might help on some broken boards which
1966					machine check when some devices' config space
1967					is read. But various workarounds are disabled
1968					and some IOMMU drivers will not work.
1969			bfsort		Sort PCI devices into breadth-first order.
1970					This sorting is done to get a device
1971					order compatible with older (<= 2.4) kernels.
1972			nobfsort	Don't sort PCI devices into breadth-first order.
1973			cbiosize=nn[KMG]	The fixed amount of bus space which is
1974					reserved for the CardBus bridge's IO window.
1975					The default value is 256 bytes.
1976			cbmemsize=nn[KMG]	The fixed amount of bus space which is
1977					reserved for the CardBus bridge's memory
1978					window. The default value is 64 megabytes.
1979			resource_alignment=
1980					Format:
1981					[<order of align>[AT]][<domain>:]<bus>:<slot>.<func>[; ..[DOT]]
1982					Specifies alignment and device to reassign
1983					aligned memory resources.
1984					If <order of align> is not specified,
1985					PAGE_SIZE is used as alignment.
1986					PCI-PCI bridge can be specified, if resource
1987					windows need to be expanded.
1988			ecrc=		Enable/disable PCIe ECRC (transaction layer
1989					end-to-end CRC checking).
1990					bios: Use BIOS/firmware settings. This is the
1991					the default.
1992					off: Turn ECRC off
1993					on: Turn ECRC on.
1994	
1995		pcie_aspm=	[PCIE] Forcibly enable or disable PCIe Active State Power
1996				Management.
1997			off	Disable ASPM.
1998			force	Enable ASPM even on devices that claim not to support it.
1999				WARNING: Forcing ASPM on may cause system lockups.
2000	
2001		pcmv=		[HW,PCMCIA] BadgePAD 4
2002	
2003		pd.		[PARIDE]
2004				See Documentation/blockdev/paride.txt.
2005	
2006		pdcchassis=	[PARISC,HW] Disable/Enable PDC Chassis Status codes at
2007				boot time.
2008				Format: { 0 | 1 }
2009				See arch/parisc/kernel/pdc_chassis.c
2010	
2011		percpu_alloc=	Select which percpu first chunk allocator to use.
2012				Currently supported values are "embed" and "page".
2013				Archs may support subset or none of the	selections.
2014				See comments in mm/percpu.c for details on each
2015				allocator.  This parameter is primarily	for debugging
2016				and performance comparison.
2017	
2018		pf.		[PARIDE]
2019				See Documentation/blockdev/paride.txt.
2020	
2021		pg.		[PARIDE]
2022				See Documentation/blockdev/paride.txt.
2023	
2024		pirq=		[SMP,APIC] Manual mp-table setup
2025				See Documentation/x86/i386/IO-APIC.txt.
2026	
2027		plip=		[PPT,NET] Parallel port network link
2028				Format: { parport<nr> | timid | 0 }
2029				See also Documentation/parport.txt.
2030	
2031		pmtmr=		[X86] Manual setup of pmtmr I/O Port. 
2032				Override pmtimer IOPort with a hex value.
2033				e.g. pmtmr=0x508
2034	
2035		pnp.debug	[PNP]
2036				Enable PNP debug messages.  This depends on the
2037				CONFIG_PNP_DEBUG_MESSAGES option.
2038	
2039		pnpacpi=	[ACPI]
2040				{ off }
2041	
2042		pnpbios=	[ISAPNP]
2043				{ on | off | curr | res | no-curr | no-res }
2044	
2045		pnp_reserve_irq=
2046				[ISAPNP] Exclude IRQs for the autoconfiguration
2047	
2048		pnp_reserve_dma=
2049				[ISAPNP] Exclude DMAs for the autoconfiguration
2050	
2051		pnp_reserve_io=	[ISAPNP] Exclude I/O ports for the autoconfiguration
2052				Ranges are in pairs (I/O port base and size).
2053	
2054		pnp_reserve_mem=
2055				[ISAPNP] Exclude memory regions for the
2056				autoconfiguration.
2057				Ranges are in pairs (memory base and size).
2058	
2059		ports=		[IP_VS_FTP] IPVS ftp helper module
2060				Default is 21.
2061				Up to 8 (IP_VS_APP_MAX_PORTS) ports
2062				may be specified.
2063				Format: <port>,<port>....
2064	
2065		print-fatal-signals=
2066				[KNL] debug: print fatal signals
2067	
2068				If enabled, warn about various signal handling
2069				related application anomalies: too many signals,
2070				too many POSIX.1 timers, fatal signals causing a
2071				coredump - etc.
2072	
2073				If you hit the warning due to signal overflow,
2074				you might want to try "ulimit -i unlimited".
2075	
2076				default: off.
2077	
2078		printk.time=	Show timing data prefixed to each printk message line
2079				Format: <bool>  (1/Y/y=enable, 0/N/n=disable)
2080	
2081		processor.max_cstate=	[HW,ACPI]
2082				Limit processor to maximum C-state
2083				max_cstate=9 overrides any DMI blacklist limit.
2084	
2085		processor.nocst	[HW,ACPI]
2086				Ignore the _CST method to determine C-states,
2087				instead using the legacy FADT method
2088	
2089		profile=	[KNL] Enable kernel profiling via /proc/profile
2090				Format: [schedule,]<number>
2091				Param: "schedule" - profile schedule points.
2092				Param: <number> - step/bucket size as a power of 2 for
2093					statistical time based profiling.
2094				Param: "sleep" - profile D-state sleeping (millisecs).
2095					Requires CONFIG_SCHEDSTATS
2096				Param: "kvm" - profile VM exits.
2097	
2098		prompt_ramdisk=	[RAM] List of RAM disks to prompt for floppy disk
2099				before loading.
2100				See Documentation/blockdev/ramdisk.txt.
2101	
2102		psmouse.proto=	[HW,MOUSE] Highest PS2 mouse protocol extension to
2103				probe for; one of (bare|imps|exps|lifebook|any).
2104		psmouse.rate=	[HW,MOUSE] Set desired mouse report rate, in reports
2105				per second.
2106		psmouse.resetafter=	[HW,MOUSE]
2107				Try to reset the device after so many bad packets
2108				(0 = never).
2109		psmouse.resolution=
2110				[HW,MOUSE] Set desired mouse resolution, in dpi.
2111		psmouse.smartscroll=
2112				[HW,MOUSE] Controls Logitech smartscroll autorepeat.
2113				0 = disabled, 1 = enabled (default).
2114	
2115		pss=		[HW,OSS] Personal Sound System (ECHO ESC614)
2116				Format:
2117				<io>,<mss_io>,<mss_irq>,<mss_dma>,<mpu_io>,<mpu_irq>
2118	
2119		pt.		[PARIDE]
2120				See Documentation/blockdev/paride.txt.
2121	
2122		pty.legacy_count=
2123				[KNL] Number of legacy pty's. Overwrites compiled-in
2124				default number.
2125	
2126		quiet		[KNL] Disable most log messages
2127	
2128		r128=		[HW,DRM]
2129	
2130		raid=		[HW,RAID]
2131				See Documentation/md.txt.
2132	
2133		ramdisk_blocksize=	[RAM]
2134				See Documentation/blockdev/ramdisk.txt.
2135	
2136		ramdisk_size=	[RAM] Sizes of RAM disks in kilobytes
2137				See Documentation/blockdev/ramdisk.txt.
2138	
2139		rcupdate.blimit=	[KNL,BOOT]
2140				Set maximum number of finished RCU callbacks to process
2141				in one batch.
2142	
2143		rcupdate.qhimark=	[KNL,BOOT]
2144				Set threshold of queued
2145				RCU callbacks over which batch limiting is disabled.
2146	
2147		rcupdate.qlowmark=	[KNL,BOOT]
2148				Set threshold of queued RCU callbacks below which
2149				batch limiting is re-enabled.
2150	
2151		rdinit=		[KNL]
2152				Format: <full_path>
2153				Run specified binary instead of /init from the ramdisk,
2154				used for early userspace startup. See initrd.
2155	
2156		reboot=		[BUGS=X86-32,BUGS=ARM,BUGS=IA-64] Rebooting mode
2157				Format: <reboot_mode>[,<reboot_mode2>[,...]]
2158				See arch/*/kernel/reboot.c or arch/*/kernel/process.c
2159	
2160		relax_domain_level=
2161				[KNL, SMP] Set scheduler's default relax_domain_level.
2162				See Documentation/cgroups/cpusets.txt.
2163	
2164		reserve=	[KNL,BUGS] Force the kernel to ignore some iomem area
2165	
2166		reservetop=	[X86-32]
2167				Format: nn[KMG]
2168				Reserves a hole at the top of the kernel virtual
2169				address space.
2170	
2171		reset_devices	[KNL] Force drivers to reset the underlying device
2172				during initialization.
2173	
2174		resume=		[SWSUSP]
2175				Specify the partition device for software suspend
2176	
2177		resume_offset=	[SWSUSP]
2178				Specify the offset from the beginning of the partition
2179				given by "resume=" at which the swap header is located,
2180				in <PAGE_SIZE> units (needed only for swap files).
2181				See  Documentation/power/swsusp-and-swap-files.txt
2182	
2183		retain_initrd	[RAM] Keep initrd memory after extraction
2184	
2185		rhash_entries=	[KNL,NET]
2186				Set number of hash buckets for route cache
2187	
2188		riscom8=	[HW,SERIAL]
2189				Format: <io_board1>[,<io_board2>[,...<io_boardN>]]
2190	
2191		ro		[KNL] Mount root device read-only on boot
2192	
2193		root=		[KNL] Root filesystem
2194	
2195		rootdelay=	[KNL] Delay (in seconds) to pause before attempting to
2196				mount the root filesystem
2197	
2198		rootflags=	[KNL] Set root filesystem mount option string
2199	
2200		rootfstype=	[KNL] Set root filesystem type
2201	
2202		rootwait	[KNL] Wait (indefinitely) for root device to show up.
2203				Useful for devices that are detected asynchronously
2204				(e.g. USB and MMC devices).
2205	
2206		rw		[KNL] Mount root device read-write on boot
2207	
2208		S		[KNL] Run init in single mode
2209	
2210		sa1100ir	[NET]
2211				See drivers/net/irda/sa1100_ir.c.
2212	
2213		sbni=		[NET] Granch SBNI12 leased line adapter
2214	
2215		sched_debug	[KNL] Enables verbose scheduler debug messages.
2216	
2217		sc1200wdt=	[HW,WDT] SC1200 WDT (watchdog) driver
2218				Format: <io>[,<timeout>[,<isapnp>]]
2219	
2220		scsi_debug_*=	[SCSI]
2221				See drivers/scsi/scsi_debug.c.
2222	
2223		scsi_default_dev_flags=
2224				[SCSI] SCSI default device flags
2225				Format: <integer>
2226	
2227		scsi_dev_flags=	[SCSI] Black/white list entry for vendor and model
2228				Format: <vendor>:<model>:<flags>
2229				(flags are integer value)
2230	
2231		scsi_logging_level=	[SCSI] a bit mask of logging levels
2232				See drivers/scsi/scsi_logging.h for bits.  Also
2233				settable via sysctl at dev.scsi.logging_level
2234				(/proc/sys/dev/scsi/logging_level).
2235				There is also a nice 'scsi_logging_level' script in the
2236				S390-tools package, available for download at
2237				http://www-128.ibm.com/developerworks/linux/linux390/s390-tools-1.5.4.html
2238	
2239		scsi_mod.scan=	[SCSI] sync (default) scans SCSI busses as they are
2240				discovered.  async scans them in kernel threads,
2241				allowing boot to proceed.  none ignores them, expecting
2242				user space to do the scan.
2243	
2244		security=	[SECURITY] Choose a security module to enable at boot.
2245				If this boot parameter is not specified, only the first
2246				security module asking for security registration will be
2247				loaded. An invalid security module name will be treated
2248				as if no module has been chosen.
2249	
2250		selinux=	[SELINUX] Disable or enable SELinux at boot time.
2251				Format: { "0" | "1" }
2252				See security/selinux/Kconfig help text.
2253				0 -- disable.
2254				1 -- enable.
2255				Default value is set via kernel config option.
2256				If enabled at boot time, /selinux/disable can be used
2257				later to disable prior to initial policy load.
2258	
2259		serialnumber	[BUGS=X86-32]
2260	
2261		shapers=	[NET]
2262				Maximal number of shapers.
2263	
2264		show_msr=	[x86] show boot-time MSR settings
2265				Format: { <integer> }
2266				Show boot-time (BIOS-initialized) MSR settings.
2267				The parameter means the number of CPUs to show,
2268				for example 1 means boot CPU only.
2269	
2270		sim710=		[SCSI,HW]
2271				See header of drivers/scsi/sim710.c.
2272	
2273		simeth=		[IA-64]
2274		simscsi=
2275	
2276		slram=		[HW,MTD]
2277	
2278		slub_debug[=options[,slabs]]	[MM, SLUB]
2279				Enabling slub_debug allows one to determine the
2280				culprit if slab objects become corrupted. Enabling
2281				slub_debug can create guard zones around objects and
2282				may poison objects when not in use. Also tracks the
2283				last alloc / free. For more information see
2284				Documentation/vm/slub.txt.
2285	
2286		slub_max_order= [MM, SLUB]
2287				Determines the maximum allowed order for slabs.
2288				A high setting may cause OOMs due to memory
2289				fragmentation. For more information see
2290				Documentation/vm/slub.txt.
2291	
2292		slub_min_objects=	[MM, SLUB]
2293				The minimum number of objects per slab. SLUB will
2294				increase the slab order up to slub_max_order to
2295				generate a sufficiently large slab able to contain
2296				the number of objects indicated. The higher the number
2297				of objects the smaller the overhead of tracking slabs
2298				and the less frequently locks need to be acquired.
2299				For more information see Documentation/vm/slub.txt.
2300	
2301		slub_min_order=	[MM, SLUB]
2302				Determines the mininum page order for slabs. Must be
2303				lower than slub_max_order.
2304				For more information see Documentation/vm/slub.txt.
2305	
2306		slub_nomerge	[MM, SLUB]
2307				Disable merging of slabs with similar size. May be
2308				necessary if there is some reason to distinguish
2309				allocs to different slabs. Debug options disable
2310				merging on their own.
2311				For more information see Documentation/vm/slub.txt.
2312	
2313		smart2=		[HW]
2314				Format: <io1>[,<io2>[,...,<io8>]]
2315	
2316		smp-alt-once	[X86-32,SMP] On a hotplug CPU system, only
2317				attempt to substitute SMP alternatives once at boot.
2318	
2319		smsc-ircc2.nopnp	[HW] Don't use PNP to discover SMC devices
2320		smsc-ircc2.ircc_cfg=	[HW] Device configuration I/O port
2321		smsc-ircc2.ircc_sir=	[HW] SIR base I/O port
2322		smsc-ircc2.ircc_fir=	[HW] FIR base I/O port
2323		smsc-ircc2.ircc_irq=	[HW] IRQ line
2324		smsc-ircc2.ircc_dma=	[HW] DMA channel
2325		smsc-ircc2.ircc_transceiver= [HW] Transceiver type:
2326					0: Toshiba Satellite 1800 (GP data pin select)
2327					1: Fast pin select (default)
2328					2: ATC IRMode
2329	
2330		snd-ad1816a=	[HW,ALSA]
2331	
2332		snd-ad1848=	[HW,ALSA]
2333	
2334		snd-ali5451=	[HW,ALSA]
2335	
2336		snd-als100=	[HW,ALSA]
2337	
2338		snd-als4000=	[HW,ALSA]
2339	
2340		snd-azt2320=	[HW,ALSA]
2341	
2342		snd-cmi8330=	[HW,ALSA]
2343	
2344		snd-cmipci=	[HW,ALSA]
2345	
2346		snd-cs4231=	[HW,ALSA]
2347	
2348		snd-cs4232=	[HW,ALSA]
2349	
2350		snd-cs4236=	[HW,ALSA]
2351	
2352		snd-cs4281=	[HW,ALSA]
2353	
2354		snd-cs46xx=	[HW,ALSA]
2355	
2356		snd-dt019x=	[HW,ALSA]
2357	
2358		snd-dummy=	[HW,ALSA]
2359	
2360		snd-emu10k1=	[HW,ALSA]
2361	
2362		snd-ens1370=	[HW,ALSA]
2363	
2364		snd-ens1371=	[HW,ALSA]
2365	
2366		snd-es968=	[HW,ALSA]
2367	
2368		snd-es1688=	[HW,ALSA]
2369	
2370		snd-es18xx=	[HW,ALSA]
2371	
2372		snd-es1938=	[HW,ALSA]
2373	
2374		snd-es1968=	[HW,ALSA]
2375	
2376		snd-fm801=	[HW,ALSA]
2377	
2378		snd-gusclassic=	[HW,ALSA]
2379	
2380		snd-gusextreme=	[HW,ALSA]
2381	
2382		snd-gusmax=	[HW,ALSA]
2383	
2384		snd-hdsp=	[HW,ALSA]
2385	
2386		snd-ice1712=	[HW,ALSA]
2387	
2388		snd-intel8x0=	[HW,ALSA]
2389	
2390		snd-interwave=	[HW,ALSA]
2391	
2392		snd-interwave-stb=
2393				[HW,ALSA]
2394	
2395		snd-korg1212=	[HW,ALSA]
2396	
2397		snd-maestro3=	[HW,ALSA]
2398	
2399		snd-mpu401=	[HW,ALSA]
2400	
2401		snd-mtpav=	[HW,ALSA]
2402	
2403		snd-nm256=	[HW,ALSA]
2404	
2405		snd-opl3sa2=	[HW,ALSA]
2406	
2407		snd-opti92x-ad1848=
2408				[HW,ALSA]
2409	
2410		snd-opti92x-cs4231=
2411				[HW,ALSA]
2412	
2413		snd-opti93x=	[HW,ALSA]
2414	
2415		snd-pmac=	[HW,ALSA]
2416	
2417		snd-rme32=	[HW,ALSA]
2418	
2419		snd-rme96=	[HW,ALSA]
2420	
2421		snd-rme9652=	[HW,ALSA]
2422	
2423		snd-sb8=	[HW,ALSA]
2424	
2425		snd-sb16=	[HW,ALSA]
2426	
2427		snd-sbawe=	[HW,ALSA]
2428	
2429		snd-serial=	[HW,ALSA]
2430	
2431		snd-sgalaxy=	[HW,ALSA]
2432	
2433		snd-sonicvibes=	[HW,ALSA]
2434	
2435		snd-sun-amd7930=
2436				[HW,ALSA]
2437	
2438		snd-sun-cs4231=	[HW,ALSA]
2439	
2440		snd-trident=	[HW,ALSA]
2441	
2442		snd-usb-audio=	[HW,ALSA,USB]
2443	
2444		snd-via82xx=	[HW,ALSA]
2445	
2446		snd-virmidi=	[HW,ALSA]
2447	
2448		snd-wavefront=	[HW,ALSA]
2449	
2450		snd-ymfpci=	[HW,ALSA]
2451	
2452		softlockup_panic=
2453				[KNL] Should the soft-lockup detector generate panics.
2454	
2455		sonypi.*=	[HW] Sony Programmable I/O Control Device driver
2456				See Documentation/sonypi.txt
2457	
2458		specialix=	[HW,SERIAL] Specialix multi-serial port adapter
2459				See Documentation/serial/specialix.txt.
2460	
2461		spia_io_base=	[HW,MTD]
2462		spia_fio_base=
2463		spia_pedr=
2464		spia_peddr=
2465	
2466		sscape=		[HW,OSS]
2467				Format: <io>,<irq>,<dma>,<mpu_io>,<mpu_irq>
2468	
2469		st=		[HW,SCSI] SCSI tape parameters (buffers, etc.)
2470				See Documentation/scsi/st.txt.
2471	
2472		stacktrace	[FTRACE]
2473				Enabled the stack tracer on boot up.
2474	
2475		sti=		[PARISC,HW]
2476				Format: <num>
2477				Set the STI (builtin display/keyboard on the HP-PARISC
2478				machines) console (graphic card) which should be used
2479				as the initial boot-console.
2480				See also comment in drivers/video/console/sticore.c.
2481	
2482		sti_font=	[HW]
2483				See comment in drivers/video/console/sticore.c.
2484	
2485		stifb=		[HW]
2486				Format: bpp:<bpp1>[:<bpp2>[:<bpp3>...]]
2487	
2488		sunrpc.min_resvport=
2489		sunrpc.max_resvport=
2490				[NFS,SUNRPC]
2491				SunRPC servers often require that client requests
2492				originate from a privileged port (i.e. a port in the
2493				range 0 < portnr < 1024).
2494				An administrator who wishes to reserve some of these
2495				ports for other uses may adjust the range that the
2496				kernel's sunrpc client considers to be privileged
2497				using these two parameters to set the minimum and
2498				maximum port values.
2499	
2500		sunrpc.pool_mode=
2501				[NFS]
2502				Control how the NFS server code allocates CPUs to
2503				service thread pools.  Depending on how many NICs
2504				you have and where their interrupts are bound, this
2505				option will affect which CPUs will do NFS serving.
2506				Note: this parameter cannot be changed while the
2507				NFS server is running.
2508	
2509				auto	    the server chooses an appropriate mode
2510					    automatically using heuristics
2511				global	    a single global pool contains all CPUs
2512				percpu	    one pool for each CPU
2513				pernode	    one pool for each NUMA node (equivalent
2514					    to global on non-NUMA machines)
2515	
2516		sunrpc.tcp_slot_table_entries=
2517		sunrpc.udp_slot_table_entries=
2518				[NFS,SUNRPC]
2519				Sets the upper limit on the number of simultaneous
2520				RPC calls that can be sent from the client to a
2521				server. Increasing these values may allow you to
2522				improve throughput, but will also increase the
2523				amount of memory reserved for use by the client.
2524	
2525		swiotlb=	[IA-64] Number of I/O TLB slabs
2526	
2527		switches=	[HW,M68k]
2528	
2529		sym53c416=	[HW,SCSI]
2530				See header of drivers/scsi/sym53c416.c.
2531	
2532		sysrq_always_enabled
2533				[KNL]
2534				Ignore sysrq setting - this boot parameter will
2535				neutralize any effect of /proc/sys/kernel/sysrq.
2536				Useful for debugging.
2537	
2538		t128=		[HW,SCSI]
2539				See header of drivers/scsi/t128.c.
2540	
2541		tdfx=		[HW,DRM]
2542	
2543		test_suspend=	[SUSPEND]
2544				Specify "mem" (for Suspend-to-RAM) or "standby" (for
2545				standby suspend) as the system sleep state to briefly
2546				enter during system startup.  The system is woken from
2547				this state using a wakeup-capable RTC alarm.
2548	
2549		thash_entries=	[KNL,NET]
2550				Set number of hash buckets for TCP connection
2551	
2552		thermal.act=	[HW,ACPI]
2553				-1: disable all active trip points in all thermal zones
2554				<degrees C>: override all lowest active trip points
2555	
2556		thermal.crt=	[HW,ACPI]
2557				-1: disable all critical trip points in all thermal zones
2558				<degrees C>: override all critical trip points
2559	
2560		thermal.nocrt=	[HW,ACPI]
2561				Set to disable actions on ACPI thermal zone
2562				critical and hot trip points.
2563	
2564		thermal.off=	[HW,ACPI]
2565				1: disable ACPI thermal control
2566	
2567		thermal.psv=	[HW,ACPI]
2568				-1: disable all passive trip points
2569				<degrees C>: override all passive trip points to this
2570				value
2571	
2572		thermal.tzp=	[HW,ACPI]
2573				Specify global default ACPI thermal zone polling rate
2574				<deci-seconds>: poll all this frequency
2575				0: no polling (default)
2576	
2577		tmscsim=	[HW,SCSI]
2578				See comment before function dc390_setup() in
2579				drivers/scsi/tmscsim.c.
2580	
2581		topology=	[S390]
2582				Format: {off | on}
2583				Specify if the kernel should make use of the cpu
2584				topology informations if the hardware supports these.
2585				The scheduler will make use of these informations and
2586				e.g. base its process migration decisions on it.
2587				Default is off.
2588	
2589		tp720=		[HW,PS2]
2590	
2591		trace_buf_size=nn[KMG]
2592				[FTRACE] will set tracing buffer size.
2593	
2594		trace_event=[event-list]
2595				[FTRACE] Set and start specified trace events in order
2596				to facilitate early boot debugging.
2597				See also Documentation/trace/events.txt
2598	
2599		trix=		[HW,OSS] MediaTrix AudioTrix Pro
2600				Format:
2601				<io>,<irq>,<dma>,<dma2>,<sb_io>,<sb_irq>,<sb_dma>,<mpu_io>,<mpu_irq>
2602	
2603		tsc=		Disable clocksource-must-verify flag for TSC.
2604				Format: <string>
2605				[x86] reliable: mark tsc clocksource as reliable, this
2606				disables clocksource verification at runtime.
2607				Used to enable high-resolution timer mode on older
2608				hardware, and in virtualized environment.
2609	
2610		turbografx.map[2|3]=	[HW,JOY]
2611				TurboGraFX parallel port interface
2612				Format:
2613				<port#>,<js1>,<js2>,<js3>,<js4>,<js5>,<js6>,<js7>
2614				See also Documentation/input/joystick-parport.txt
2615	
2616		u14-34f=	[HW,SCSI] UltraStor 14F/34F SCSI host adapter
2617				See header of drivers/scsi/u14-34f.c.
2618	
2619		uart401=	[HW,OSS]
2620				Format: <io>,<irq>
2621	
2622		uart6850=	[HW,OSS]
2623				Format: <io>,<irq>
2624	
2625		uhash_entries=	[KNL,NET]
2626				Set number of hash buckets for UDP/UDP-Lite connections
2627	
2628		uhci-hcd.ignore_oc=
2629				[USB] Ignore overcurrent events (default N).
2630				Some badly-designed motherboards generate lots of
2631				bogus events, for ports that aren't wired to
2632				anything.  Set this parameter to avoid log spamming.
2633				Note that genuine overcurrent events won't be
2634				reported either.
2635	
2636		unknown_nmi_panic
2637				[X86]
2638				Set unknown_nmi_panic=1 early on boot.
2639	
2640		usbcore.autosuspend=
2641				[USB] The autosuspend time delay (in seconds) used
2642				for newly-detected USB devices (default 2).  This
2643				is the time required before an idle device will be
2644				autosuspended.  Devices for which the delay is set
2645				to a negative value won't be autosuspended at all.
2646	
2647		usbcore.usbfs_snoop=
2648				[USB] Set to log all usbfs traffic (default 0 = off).
2649	
2650		usbcore.blinkenlights=
2651				[USB] Set to cycle leds on hubs (default 0 = off).
2652	
2653		usbcore.old_scheme_first=
2654				[USB] Start with the old device initialization
2655				scheme (default 0 = off).
2656	
2657		usbcore.use_both_schemes=
2658				[USB] Try the other device initialization scheme
2659				if the first one fails (default 1 = enabled).
2660	
2661		usbcore.initial_descriptor_timeout=
2662				[USB] Specifies timeout for the initial 64-byte
2663	                        USB_REQ_GET_DESCRIPTOR request in milliseconds
2664				(default 5000 = 5.0 seconds).
2665	
2666		usbhid.mousepoll=
2667				[USBHID] The interval which mice are to be polled at.
2668	
2669		usb-storage.delay_use=
2670				[UMS] The delay in seconds before a new device is
2671				scanned for Logical Units (default 5).
2672	
2673		usb-storage.quirks=
2674				[UMS] A list of quirks entries to supplement or
2675				override the built-in unusual_devs list.  List
2676				entries are separated by commas.  Each entry has
2677				the form VID:PID:Flags where VID and PID are Vendor
2678				and Product ID values (4-digit hex numbers) and
2679				Flags is a set of characters, each corresponding
2680				to a common usb-storage quirk flag as follows:
2681					a = SANE_SENSE (collect more than 18 bytes
2682						of sense data);
2683					b = BAD_SENSE (don't collect more than 18
2684						bytes of sense data);
2685					c = FIX_CAPACITY (decrease the reported
2686						device capacity by one sector);
2687					h = CAPACITY_HEURISTICS (decrease the
2688						reported device capacity by one
2689						sector if the number is odd);
2690					i = IGNORE_DEVICE (don't bind to this
2691						device);
2692					l = NOT_LOCKABLE (don't try to lock and
2693						unlock ejectable media);
2694					m = MAX_SECTORS_64 (don't transfer more
2695						than 64 sectors = 32 KB at a time);
2696					o = CAPACITY_OK (accept the capacity
2697						reported by the device);
2698					r = IGNORE_RESIDUE (the device reports
2699						bogus residue values);
2700					s = SINGLE_LUN (the device has only one
2701						Logical Unit);
2702					w = NO_WP_DETECT (don't test whether the
2703						medium is write-protected).
2704				Example: quirks=0419:aaf5:rl,0421:0433:rc
2705	
2706		vdso=		[X86,SH]
2707				vdso=2: enable compat VDSO (default with COMPAT_VDSO)
2708				vdso=1: enable VDSO (default)
2709				vdso=0: disable VDSO mapping
2710	
2711		vdso32=		[X86]
2712				vdso32=2: enable compat VDSO (default with COMPAT_VDSO)
2713				vdso32=1: enable 32-bit VDSO (default)
2714				vdso32=0: disable 32-bit VDSO mapping
2715	
2716		vector=		[IA-64,SMP]
2717				vector=percpu: enable percpu vector domain
2718	
2719		video=		[FB] Frame buffer configuration
2720				See Documentation/fb/modedb.txt.
2721	
2722		vga=		[BOOT,X86-32] Select a particular video mode
2723				See Documentation/x86/boot.txt and
2724				Documentation/svga.txt.
2725				Use vga=ask for menu.
2726				This is actually a boot loader parameter; the value is
2727				passed to the kernel using a special protocol.
2728	
2729		vmalloc=nn[KMG]	[KNL,BOOT] Forces the vmalloc area to have an exact
2730				size of <nn>. This can be used to increase the
2731				minimum size (128MB on x86). It can also be used to
2732				decrease the size and leave more room for directly
2733				mapped kernel RAM.
2734	
2735		vmhalt=		[KNL,S390] Perform z/VM CP command after system halt.
2736				Format: <command>
2737	
2738		vmpanic=	[KNL,S390] Perform z/VM CP command after kernel panic.
2739				Format: <command>
2740	
2741		vmpoff=		[KNL,S390] Perform z/VM CP command after power off.
2742				Format: <command>
2743	
2744		vt.cur_default=	[VT] Default cursor shape.
2745				Format: 0xCCBBAA, where AA, BB, and CC are the same as
2746				the parameters of the <Esc>[?A;B;Cc escape sequence;
2747				see VGA-softcursor.txt. Default: 2 = underline.
2748	
2749		vt.default_blu=	[VT]
2750				Format: <blue0>,<blue1>,<blue2>,...,<blue15>
2751				Change the default blue palette of the console.
2752				This is a 16-member array composed of values
2753				ranging from 0-255.
2754	
2755		vt.default_grn=	[VT]
2756				Format: <green0>,<green1>,<green2>,...,<green15>
2757				Change the default green palette of the console.
2758				This is a 16-member array composed of values
2759				ranging from 0-255.
2760	
2761		vt.default_red=	[VT]
2762				Format: <red0>,<red1>,<red2>,...,<red15>
2763				Change the default red palette of the console.
2764				This is a 16-member array composed of values
2765				ranging from 0-255.
2766	
2767		vt.default_utf8=
2768				[VT]
2769				Format=<0|1>
2770				Set system-wide default UTF-8 mode for all tty's.
2771				Default is 1, i.e. UTF-8 mode is enabled for all
2772				newly opened terminals.
2773	
2774		vt.global_cursor_default=
2775				[VT]
2776				Format=<-1|0|1>
2777				Set system-wide default for whether a cursor
2778				is shown on new VTs. Default is -1,
2779				i.e. cursors will be created by default unless
2780				overridden by individual drivers. 0 will hide
2781				cursors, 1 will display them.
2782	
2783		waveartist=	[HW,OSS]
2784				Format: <io>,<irq>,<dma>,<dma2>
2785	
2786		wd33c93=	[HW,SCSI]
2787				See header of drivers/scsi/wd33c93.c.
2788	
2789		wd7000=		[HW,SCSI]
2790				See header of drivers/scsi/wd7000.c.
2791	
2792		wdt=		[WDT] Watchdog
2793				See Documentation/watchdog/wdt.txt.
2794	
2795		x2apic_phys	[X86-64,APIC] Use x2apic physical mode instead of
2796				default x2apic cluster mode on platforms
2797				supporting x2apic.
2798	
2799		xd=		[HW,XT] Original XT pre-IDE (RLL encoded) disks.
2800		xd_geo=		See header of drivers/block/xd.c.
2801	
2802		xirc2ps_cs=	[NET,PCMCIA]
2803				Format:
2804				<irq>,<irq_mask>,<io>,<full_duplex>,<do_sound>,<lockup_hack>[,<irq2>[,<irq3>[,<irq4>]]]
2805	
2806	______________________________________________________________________
2807	
2808	TODO:
2809	
2810		Add documentation for ALSA options.
2811		Add more DRM drivers.
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