kernel-parameters.txt 89.2 KB
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                          Kernel Parameters
                          ~~~~~~~~~~~~~~~~~
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The following is a consolidated list of the kernel parameters as implemented
(mostly) by the __setup() macro and sorted into English Dictionary order
(defined as ignoring all punctuation and sorting digits before letters in a
case insensitive manner), and with descriptions where known.

Module parameters for loadable modules are specified only as the
parameter name with optional '=' and value as appropriate, such as:

	modprobe usbcore blinkenlights=1

Module parameters for modules that are built into the kernel image
are specified on the kernel command line with the module name plus
'.' plus parameter name, with '=' and value if appropriate, such as:

	usbcore.blinkenlights=1

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Hyphens (dashes) and underscores are equivalent in parameter names, so
	log_buf_len=1M print-fatal-signals=1
can also be entered as
	log-buf-len=1M print_fatal_signals=1


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This document may not be entirely up to date and comprehensive. The command
"modinfo -p ${modulename}" shows a current list of all parameters of a loadable
module. Loadable modules, after being loaded into the running kernel, also
reveal their parameters in /sys/module/${modulename}/parameters/. Some of these
parameters may be changed at runtime by the command
"echo -n ${value} > /sys/module/${modulename}/parameters/${parm}".

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The parameters listed below are only valid if certain kernel build options were
enabled and if respective hardware is present. The text in square brackets at
the beginning of each description states the restrictions within which a
parameter is applicable:
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	ACPI	ACPI support is enabled.
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	AGP	AGP (Accelerated Graphics Port) is enabled.
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	ALSA	ALSA sound support is enabled.
	APIC	APIC support is enabled.
	APM	Advanced Power Management support is enabled.
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	AVR32	AVR32 architecture is enabled.
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	AX25	Appropriate AX.25 support is enabled.
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	BLACKFIN Blackfin architecture is enabled.
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	DRM	Direct Rendering Management support is enabled.
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	EDD	BIOS Enhanced Disk Drive Services (EDD) is enabled
	EFI	EFI Partitioning (GPT) is enabled
	EIDE	EIDE/ATAPI support is enabled.
	FB	The frame buffer device is enabled.
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	GCOV	GCOV profiling is enabled.
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	HW	Appropriate hardware is enabled.
	IA-64	IA-64 architecture is enabled.
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	IMA     Integrity measurement architecture is enabled.
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	IOSCHED	More than one I/O scheduler is enabled.
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	IP_PNP	IP DHCP, BOOTP, or RARP is enabled.
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	ISAPNP	ISA PnP code is enabled.
	ISDN	Appropriate ISDN support is enabled.
	JOY	Appropriate joystick support is enabled.
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	KVM	Kernel Virtual Machine support is enabled.
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	LIBATA  Libata driver is enabled
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	LP	Printer support is enabled.
	LOOP	Loopback device support is enabled.
	M68k	M68k architecture is enabled.
			These options have more detailed description inside of
			Documentation/m68k/kernel-options.txt.
	MCA	MCA bus support is enabled.
	MDA	MDA console support is enabled.
	MOUSE	Appropriate mouse support is enabled.
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	MSI	Message Signaled Interrupts (PCI).
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	MTD	MTD (Memory Technology Device) support is enabled.
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	NET	Appropriate network support is enabled.
	NUMA	NUMA support is enabled.
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	GENERIC_TIME The generic timeofday code is enabled.
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	NFS	Appropriate NFS support is enabled.
	OSS	OSS sound support is enabled.
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	PV_OPS	A paravirtualized kernel is enabled.
	PARIDE	The ParIDE (parallel port IDE) subsystem is enabled.
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	PARISC	The PA-RISC architecture is enabled.
	PCI	PCI bus support is enabled.
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	PCIE	PCI Express support is enabled.
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	PCMCIA	The PCMCIA subsystem is enabled.
	PNP	Plug & Play support is enabled.
	PPC	PowerPC architecture is enabled.
	PPT	Parallel port support is enabled.
	PS2	Appropriate PS/2 support is enabled.
	RAM	RAM disk support is enabled.
	S390	S390 architecture is enabled.
	SCSI	Appropriate SCSI support is enabled.
			A lot of drivers has their options described inside of
			Documentation/scsi/.
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	SECURITY Different security models are enabled.
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	SELINUX SELinux support is enabled.
	SERIAL	Serial support is enabled.
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	SH	SuperH architecture is enabled.
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	SMP	The kernel is an SMP kernel.
	SPARC	Sparc architecture is enabled.
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	SWSUSP	Software suspend (hibernation) is enabled.
	SUSPEND	System suspend states are enabled.
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	FTRACE	Function tracing enabled.
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	TS	Appropriate touchscreen support is enabled.
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	UMS	USB Mass Storage support is enabled.
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	USB	USB support is enabled.
	USBHID	USB Human Interface Device support is enabled.
	V4L	Video For Linux support is enabled.
	VGA	The VGA console has been enabled.
	VT	Virtual terminal support is enabled.
	WDT	Watchdog support is enabled.
	XT	IBM PC/XT MFM hard disk support is enabled.
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	X86-32	X86-32, aka i386 architecture is enabled.
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	X86-64	X86-64 architecture is enabled.
			More X86-64 boot options can be found in
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			Documentation/x86/x86_64/boot-options.txt .
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	X86	Either 32bit or 64bit x86 (same as X86-32+X86-64)
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In addition, the following text indicates that the option:

	BUGS=	Relates to possible processor bugs on the said processor.
	KNL	Is a kernel start-up parameter.
	BOOT	Is a boot loader parameter.

Parameters denoted with BOOT are actually interpreted by the boot
loader, and have no meaning to the kernel directly.
Do not modify the syntax of boot loader parameters without extreme
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need or coordination with <Documentation/x86/boot.txt>.
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There are also arch-specific kernel-parameters not documented here.
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See for example <Documentation/x86/x86_64/boot-options.txt>.
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Note that ALL kernel parameters listed below are CASE SENSITIVE, and that
a trailing = on the name of any parameter states that that parameter will
be entered as an environment variable, whereas its absence indicates that
it will appear as a kernel argument readable via /proc/cmdline by programs
running once the system is up.

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The number of kernel parameters is not limited, but the length of the
complete command line (parameters including spaces etc.) is limited to
a fixed number of characters. This limit depends on the architecture
and is between 256 and 4096 characters. It is defined in the file
./include/asm/setup.h as COMMAND_LINE_SIZE.


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	acpi=		[HW,ACPI,X86]
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			Advanced Configuration and Power Interface
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			Format: { force | off | ht | strict | noirq | rsdt }
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			force -- enable ACPI if default was off
			off -- disable ACPI if default was on
			noirq -- do not use ACPI for IRQ routing
			ht -- run only enough ACPI to enable Hyper Threading
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			strict -- Be less tolerant of platforms that are not
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				strictly ACPI specification compliant.
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			rsdt -- prefer RSDT over (default) XSDT
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			See also Documentation/power/pm.txt, pci=noacpi
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	acpi_apic_instance=	[ACPI, IOAPIC]
			Format: <int>
			2: use 2nd APIC table, if available
			1,0: use 1st APIC table
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			default: 0
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	acpi_backlight=	[HW,ACPI]
			acpi_backlight=vendor
			acpi_backlight=video
			If set to vendor, prefer vendor specific driver
			(e.g. thinkpad_acpi, sony_acpi, etc.) instead
			of the ACPI video.ko driver.

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	acpi.debug_layer=	[HW,ACPI,ACPI_DEBUG]
	acpi.debug_level=	[HW,ACPI,ACPI_DEBUG]
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			Format: <int>
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			CONFIG_ACPI_DEBUG must be enabled to produce any ACPI
			debug output.  Bits in debug_layer correspond to a
			_COMPONENT in an ACPI source file, e.g.,
			    #define _COMPONENT ACPI_PCI_COMPONENT
			Bits in debug_level correspond to a level in
			ACPI_DEBUG_PRINT statements, e.g.,
			    ACPI_DEBUG_PRINT((ACPI_DB_INFO, ...
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			The debug_level mask defaults to "info".  See
			Documentation/acpi/debug.txt for more information about
			debug layers and levels.
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			Enable processor driver info messages:
			    acpi.debug_layer=0x20000000
			Enable PCI/PCI interrupt routing info messages:
			    acpi.debug_layer=0x400000
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			Enable AML "Debug" output, i.e., stores to the Debug
			object while interpreting AML:
			    acpi.debug_layer=0xffffffff acpi.debug_level=0x2
			Enable all messages related to ACPI hardware:
			    acpi.debug_layer=0x2 acpi.debug_level=0xffffffff

			Some values produce so much output that the system is
			unusable.  The "log_buf_len" parameter may be useful
			if you need to capture more output.
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	acpi_display_output=	[HW,ACPI]
			acpi_display_output=vendor
			acpi_display_output=video
			See above.

	acpi_irq_balance [HW,ACPI]
			ACPI will balance active IRQs
			default in APIC mode

	acpi_irq_nobalance [HW,ACPI]
			ACPI will not move active IRQs (default)
			default in PIC mode

	acpi_irq_isa=	[HW,ACPI] If irq_balance, mark listed IRQs used by ISA
			Format: <irq>,<irq>...

	acpi_irq_pci=	[HW,ACPI] If irq_balance, clear listed IRQs for
			use by PCI
			Format: <irq>,<irq>...

	acpi_no_auto_ssdt	[HW,ACPI] Disable automatic loading of SSDT

	acpi_os_name=	[HW,ACPI] Tell ACPI BIOS the name of the OS
			Format: To spoof as Windows 98: ="Microsoft Windows"

	acpi_osi=	[HW,ACPI] Modify list of supported OS interface strings
			acpi_osi="string1"	# add string1 -- only one string
			acpi_osi="!string2"	# remove built-in string2
			acpi_osi=		# disable all strings

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	acpi_pm_good	[X86]
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			Override the pmtimer bug detection: force the kernel
			to assume that this machine's pmtimer latches its value
			and always returns good values.

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	acpi_sci=	[HW,ACPI] ACPI System Control Interrupt trigger mode
			Format: { level | edge | high | low }

	acpi_serialize	[HW,ACPI] force serialization of AML methods

	acpi_skip_timer_override [HW,ACPI]
			Recognize and ignore IRQ0/pin2 Interrupt Override.
			For broken nForce2 BIOS resulting in XT-PIC timer.

	acpi_sleep=	[HW,ACPI] Sleep options
			Format: { s3_bios, s3_mode, s3_beep, s4_nohwsig,
				  old_ordering, s4_nonvs }
			See Documentation/power/video.txt for information on
			s3_bios and s3_mode.
			s3_beep is for debugging; it makes the PC's speaker beep
			as soon as the kernel's real-mode entry point is called.
			s4_nohwsig prevents ACPI hardware signature from being
			used during resume from hibernation.
			old_ordering causes the ACPI 1.0 ordering of the _PTS
			control method, with respect to putting devices into
			low power states, to be enforced (the ACPI 2.0 ordering
			of _PTS is used by default).
			s4_nonvs prevents the kernel from saving/restoring the
			ACPI NVS memory during hibernation.

	acpi_use_timer_override [HW,ACPI]
			Use timer override. For some broken Nvidia NF5 boards
			that require a timer override, but don't have HPET

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	acpi_enforce_resources=	[ACPI]
			{ strict | lax | no }
			Check for resource conflicts between native drivers
			and ACPI OperationRegions (SystemIO and SystemMemory
			only). IO ports and memory declared in ACPI might be
			used by the ACPI subsystem in arbitrary AML code and
			can interfere with legacy drivers.
			strict (default): access to resources claimed by ACPI
			is denied; legacy drivers trying to access reserved
			resources will fail to bind to device using them.
			lax: access to resources claimed by ACPI is allowed;
			legacy drivers trying to access reserved resources
			will bind successfully but a warning message is logged.
			no: ACPI OperationRegions are not marked as reserved,
			no further checks are performed.

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	ad1848=		[HW,OSS]
			Format: <io>,<irq>,<dma>,<dma2>,<type>

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	add_efi_memmap	[EFI; X86] Include EFI memory map in
			kernel's map of available physical RAM.

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	advansys=	[HW,SCSI]
			See header of drivers/scsi/advansys.c.

	advwdt=		[HW,WDT] Advantech WDT
			Format: <iostart>,<iostop>

	aedsp16=	[HW,OSS] Audio Excel DSP 16
			Format: <io>,<irq>,<dma>,<mss_io>,<mpu_io>,<mpu_irq>
			See also header of sound/oss/aedsp16.c.
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	agp=		[AGP]
			{ off | try_unsupported }
			off: disable AGP support
			try_unsupported: try to drive unsupported chipsets
				(may crash computer or cause data corruption)

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	aha152x=	[HW,SCSI]
			See Documentation/scsi/aha152x.txt.

	aha1542=	[HW,SCSI]
			Format: <portbase>[,<buson>,<busoff>[,<dmaspeed>]]

	aic7xxx=	[HW,SCSI]
			See Documentation/scsi/aic7xxx.txt.

	aic79xx=	[HW,SCSI]
			See Documentation/scsi/aic79xx.txt.

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	amd_iommu=	[HW,X86-84]
			Pass parameters to the AMD IOMMU driver in the system.
			Possible values are:
			isolate - enable device isolation (each device, as far
			          as possible, will get its own protection
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			          domain) [default]
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			share - put every device behind one IOMMU into the
				same protection domain
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			fullflush - enable flushing of IO/TLB entries when
				    they are unmapped. Otherwise they are
				    flushed before they will be reused, which
				    is a lot of faster

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	amijoy.map=	[HW,JOY] Amiga joystick support
			Map of devices attached to JOY0DAT and JOY1DAT
			Format: <a>,<b>
			See also Documentation/kernel/input/joystick.txt

	analog.map=	[HW,JOY] Analog joystick and gamepad support
			Specifies type or capabilities of an analog joystick
			connected to one of 16 gameports
			Format: <type1>,<type2>,..<type16>

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	apc=		[HW,SPARC]
			Power management functions (SPARCstation-4/5 + deriv.)
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			Format: noidle
			Disable APC CPU standby support. SPARCstation-Fox does
			not play well with APC CPU idle - disable it if you have
			APC and your system crashes randomly.

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	apic=		[APIC,X86-32] Advanced Programmable Interrupt Controller
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			Change the output verbosity whilst booting
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			Format: { quiet (default) | verbose | debug }
			Change the amount of debugging information output
			when initialising the APIC and IO-APIC components.
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	show_lapic=	[APIC,X86] Advanced Programmable Interrupt Controller
			Limit apic dumping. The parameter defines the maximal
			number of local apics being dumped. Also it is possible
			to set it to "all" by meaning -- no limit here.
			Format: { 1 (default) | 2 | ... | all }.
			The parameter valid if only apic=debug or
			apic=verbose is specified.
			Example: apic=debug show_lapic=all

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	apm=		[APM] Advanced Power Management
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			See header of arch/x86/kernel/apm_32.c.
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	arcrimi=	[HW,NET] ARCnet - "RIM I" (entirely mem-mapped) cards
			Format: <io>,<irq>,<nodeID>

	ataflop=	[HW,M68k]

	atarimouse=	[HW,MOUSE] Atari Mouse

	atascsi=	[HW,SCSI] Atari SCSI

	atkbd.extra=	[HW] Enable extra LEDs and keys on IBM RapidAccess,
			EzKey and similar keyboards

	atkbd.reset=	[HW] Reset keyboard during initialization

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	atkbd.set=	[HW] Select keyboard code set
			Format: <int> (2 = AT (default), 3 = PS/2)
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	atkbd.scroll=	[HW] Enable scroll wheel on MS Office and similar
			keyboards

	atkbd.softraw=	[HW] Choose between synthetic and real raw mode
			Format: <bool> (0 = real, 1 = synthetic (default))
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	atkbd.softrepeat= [HW]
			Use software keyboard repeat
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	autotest	[IA64]

	baycom_epp=	[HW,AX25]
			Format: <io>,<mode>
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	baycom_par=	[HW,AX25] BayCom Parallel Port AX.25 Modem
			Format: <io>,<mode>
			See header of drivers/net/hamradio/baycom_par.c.

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	baycom_ser_fdx=	[HW,AX25]
			BayCom Serial Port AX.25 Modem (Full Duplex Mode)
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			Format: <io>,<irq>,<mode>[,<baud>]
			See header of drivers/net/hamradio/baycom_ser_fdx.c.

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	baycom_ser_hdx=	[HW,AX25]
			BayCom Serial Port AX.25 Modem (Half Duplex Mode)
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			Format: <io>,<irq>,<mode>
			See header of drivers/net/hamradio/baycom_ser_hdx.c.

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	boot_delay=	Milliseconds to delay each printk during boot.
			Values larger than 10 seconds (10000) are changed to
			no delay (0).
			Format: integer

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	bootmem_debug	[KNL] Enable bootmem allocator debug messages.

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	bttv.card=	[HW,V4L] bttv (bt848 + bt878 based grabber cards)
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	bttv.radio=	Most important insmod options are available as
			kernel args too.
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	bttv.pll=	See Documentation/video4linux/bttv/Insmod-options
	bttv.tuner=	and Documentation/video4linux/bttv/CARDLIST

	BusLogic=	[HW,SCSI]
			See drivers/scsi/BusLogic.c, comment before function
			BusLogic_ParseDriverOptions().

	c101=		[NET] Moxa C101 synchronous serial card

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	cachesize=	[BUGS=X86-32] Override level 2 CPU cache size detection.
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			Sometimes CPU hardware bugs make them report the cache
			size incorrectly. The kernel will attempt work arounds
			to fix known problems, but for some CPUs it is not
			possible to determine what the correct size should be.
			This option provides an override for these situations.

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	capability.disable=
			[SECURITY] Disable capabilities.  This would normally
			be used only if an alternative security model is to be
			configured.  Potentially dangerous and should only be
			used if you are entirely sure of the consequences.

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	ccw_timeout_log [S390]
			See Documentation/s390/CommonIO for details.
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	cgroup_disable= [KNL] Disable a particular controller
			Format: {name of the controller(s) to disable}
				{Currently supported controllers - "memory"}

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	checkreqprot	[SELINUX] Set initial checkreqprot flag value.
			Format: { "0" | "1" }
			See security/selinux/Kconfig help text.
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			0 -- check protection applied by kernel (includes
				any implied execute protection).
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			1 -- check protection requested by application.
			Default value is set via a kernel config option.
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			Value can be changed at runtime via
				/selinux/checkreqprot.

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	cio_ignore=	[S390]
			See Documentation/s390/CommonIO for details.

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	clock=		[BUGS=X86-32, HW] gettimeofday clocksource override.
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			[Deprecated]
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			Forces specified clocksource (if available) to be used
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			when calculating gettimeofday(). If specified
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			clocksource is not available, it defaults to PIT.
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			Format: { pit | tsc | cyclone | pmtmr }

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	clocksource=	[GENERIC_TIME] Override the default clocksource
			Format: <string>
			Override the default clocksource and use the clocksource
			with the name specified.
			Some clocksource names to choose from, depending on
			the platform:
			[all] jiffies (this is the base, fallback clocksource)
			[ACPI] acpi_pm
			[ARM] imx_timer1,OSTS,netx_timer,mpu_timer2,
				pxa_timer,timer3,32k_counter,timer0_1
			[AVR32] avr32
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			[X86-32] pit,hpet,tsc,vmi-timer;
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				scx200_hrt on Geode; cyclone on IBM x440
			[MIPS] MIPS
			[PARISC] cr16
			[S390] tod
			[SH] SuperH
			[SPARC64] tick
			[X86-64] hpet,tsc

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	clearcpuid=BITNUM [X86]
			Disable CPUID feature X for the kernel. See
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			arch/x86/include/asm/cpufeature.h for the valid bit
			numbers. Note the Linux specific bits are not necessarily
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			stable over kernel options, but the vendor specific
			ones should be.
			Also note that user programs calling CPUID directly
			or using the feature without checking anything
			will still see it. This just prevents it from
			being used by the kernel or shown in /proc/cpuinfo.
			Also note the kernel might malfunction if you disable
			some critical bits.

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	cmo_free_hint=	[PPC] Format: { yes | no }
			Specify whether pages are marked as being inactive
			when they are freed.  This is used in CMO environments
			to determine OS memory pressure for page stealing by
			a hypervisor.
			Default: yes

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	code_bytes	[X86] How many bytes of object code to print
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			in an oops report.
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			Range: 0 - 8192
			Default: 64

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	com20020=	[HW,NET] ARCnet - COM20020 chipset
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			Format:
			<io>[,<irq>[,<nodeID>[,<backplane>[,<ckp>[,<timeout>]]]]]
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	com90io=	[HW,NET] ARCnet - COM90xx chipset (IO-mapped buffers)
			Format: <io>[,<irq>]

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	com90xx=	[HW,NET]
			ARCnet - COM90xx chipset (memory-mapped buffers)
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			Format: <io>[,<irq>[,<memstart>]]

	condev=		[HW,S390] console device
	conmode=
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	console=	[KNL] Output console device and options.

		tty<n>	Use the virtual console device <n>.

		ttyS<n>[,options]
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		ttyUSB0[,options]
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			Use the specified serial port.  The options are of
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			the form "bbbbpnf", where "bbbb" is the baud rate,
			"p" is parity ("n", "o", or "e"), "n" is number of
			bits, and "f" is flow control ("r" for RTS or
			omit it).  Default is "9600n8".

			See Documentation/serial-console.txt for more
			information.  See
			Documentation/networking/netconsole.txt for an
			alternative.
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		uart[8250],io,<addr>[,options]
		uart[8250],mmio,<addr>[,options]
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			Start an early, polled-mode console on the 8250/16550
			UART at the specified I/O port or MMIO address,
			switching to the matching ttyS device later.  The
			options are the same as for ttyS, above.

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                If the device connected to the port is not a TTY but a braille
                device, prepend "brl," before the device type, for instance
			console=brl,ttyS0
		For now, only VisioBraille is supported.

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	consoleblank=	[KNL] The console blank (screen saver) timeout in
			seconds. Defaults to 10*60 = 10mins. A value of 0
			disables the blank timer.

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	coredump_filter=
			[KNL] Change the default value for
			/proc/<pid>/coredump_filter.
			See also Documentation/filesystems/proc.txt.

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	cpcihp_generic=	[HW,PCI] Generic port I/O CompactPCI driver
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			Format:
			<first_slot>,<last_slot>,<port>,<enum_bit>[,<debug>]
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	crashkernel=nn[KMG]@ss[KMG]
			[KNL] Reserve a chunk of physical memory to
			hold a kernel to switch to with kexec on panic.

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	crashkernel=range1:size1[,range2:size2,...][@offset]
			[KNL] Same as above, but depends on the memory
			in the running system. The syntax of range is
			start-[end] where start and end are both
			a memory unit (amount[KMG]). See also
			Documentation/kdump/kdump.txt for a example.

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	cs89x0_dma=	[HW,NET]
			Format: <dma>

	cs89x0_media=	[HW,NET]
			Format: { rj45 | aui | bnc }
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	dasd=		[HW,NET]
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			See header of drivers/s390/block/dasd_devmap.c.

	db9.dev[2|3]=	[HW,JOY] Multisystem joystick support via parallel port
			(one device per port)
			Format: <port#>,<type>
			See also Documentation/input/joystick-parport.txt

	debug		[KNL] Enable kernel debugging (events log level).

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	debug_locks_verbose=
			[KNL] verbose self-tests
			Format=<0|1>
			Print debugging info while doing the locking API
			self-tests.
			We default to 0 (no extra messages), setting it to
			1 will print _a lot_ more information - normally
			only useful to kernel developers.

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	debug_objects	[KNL] Enable object debugging

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	no_debug_objects
			[KNL] Disable object debugging

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	debugpat	[X86] Enable PAT debugging

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	decnet.addr=	[HW,NET]
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			Format: <area>[,<node>]
			See also Documentation/networking/decnet.txt.

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	default_hugepagesz=
			[same as hugepagesz=] The size of the default
			HugeTLB page size. This is the size represented by
			the legacy /proc/ hugepages APIs, used for SHM, and
			default size when mounting hugetlbfs filesystems.
			Defaults to the default architecture's huge page size
			if not specified.
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	dhash_entries=	[KNL]
			Set number of hash buckets for dentry cache.
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	digi=		[HW,SERIAL]
			IO parameters + enable/disable command.

	digiepca=	[HW,SERIAL]
			See drivers/char/README.epca and
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			Documentation/serial/digiepca.txt.
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	disable_mtrr_cleanup [X86]
			The kernel tries to adjust MTRR layout from continuous
			to discrete, to make X server driver able to add WB
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			entry later. This parameter disables that.
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	disable_mtrr_trim [X86, Intel and AMD only]
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			By default the kernel will trim any uncacheable
			memory out of your available memory pool based on
			MTRR settings.  This parameter disables that behavior,
			possibly causing your machine to run very slowly.

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	disable_timer_pin_1 [X86]
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			Disable PIN 1 of APIC timer
			Can be useful to work around chipset bugs.

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	dmasound=	[HW,OSS] Sound subsystem buffers

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	dma_debug=off	If the kernel is compiled with DMA_API_DEBUG support,
			this option disables the debugging code at boot.

	dma_debug_entries=<number>
			This option allows to tune the number of preallocated
			entries for DMA-API debugging code. One entry is
			required per DMA-API allocation. Use this if the
			DMA-API debugging code disables itself because the
			architectural default is too low.

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	dma_debug_driver=<driver_name>
			With this option the DMA-API debugging driver
			filter feature can be enabled at boot time. Just
			pass the driver to filter for as the parameter.
			The filter can be disabled or changed to another
			driver later using sysfs.

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	dscc4.setup=	[NET]

	dtc3181e=	[HW,SCSI]

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	dynamic_printk	Enables pr_debug()/dev_dbg() calls if
			CONFIG_DYNAMIC_PRINTK_DEBUG has been enabled.
			These can also be switched on/off via
			<debugfs>/dynamic_printk/modules

	earlycon=	[KNL] Output early console device and options.
		uart[8250],io,<addr>[,options]
		uart[8250],mmio,<addr>[,options]
			Start an early, polled-mode console on the 8250/16550
			UART at the specified I/O port or MMIO address.
			The options are the same as for ttyS, above.

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	earlyprintk=	[X86,SH,BLACKFIN]
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			earlyprintk=vga
			earlyprintk=serial[,ttySn[,baudrate]]
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			earlyprintk=ttySn[,baudrate]
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			earlyprintk=dbgp[debugController#]
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			Append ",keep" to not disable it when the real console
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			takes over.

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			Only vga or serial or usb debug port at a time.
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			Currently only ttyS0 and ttyS1 are supported.

			Interaction with the standard serial driver is not
			very good.

			The VGA output is eventually overwritten by the real
			console.

	eata=		[HW,SCSI]

	edd=		[EDD]
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			Format: {"off" | "on" | "skip[mbr]"}
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	eisa_irq_edge=	[PARISC,HW]
			See header of drivers/parisc/eisa.c.

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	elanfreq=	[X86-32]
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			See comment before function elanfreq_setup() in
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			arch/x86/kernel/cpu/cpufreq/elanfreq.c.
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	elevator=	[IOSCHED]
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			Format: {"anticipatory" | "cfq" | "deadline" | "noop"}
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			See Documentation/block/as-iosched.txt and
			Documentation/block/deadline-iosched.txt for details.

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	elfcorehdr=	[IA64,PPC,SH,X86]
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			Specifies physical address of start of kernel core
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			image elf header. Generally kexec loader will
			pass this option to capture kernel.
			See Documentation/kdump/kdump.txt for details.
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	enable_mtrr_cleanup [X86]
			The kernel tries to adjust MTRR layout from continuous
			to discrete, to make X server driver able to add WB
			entry later. This parameter enables that.

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	enable_timer_pin_1 [X86]
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			Enable PIN 1 of APIC timer
			Can be useful to work around chipset bugs
			(in particular on some ATI chipsets).
			The kernel tries to set a reasonable default.

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	enforcing	[SELINUX] Set initial enforcing status.
			Format: {"0" | "1"}
			See security/selinux/Kconfig help text.
			0 -- permissive (log only, no denials).
			1 -- enforcing (deny and log).
			Default value is 0.
			Value can be changed at runtime via /selinux/enforce.

	ether=		[HW,NET] Ethernet cards parameters
			This option is obsoleted by the "netdev=" option, which
			has equivalent usage. See its documentation for details.

	eurwdt=		[HW,WDT] Eurotech CPU-1220/1410 onboard watchdog.
			Format: <io>[,<irq>]

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	failslab=
	fail_page_alloc=
	fail_make_request=[KNL]
			General fault injection mechanism.
			Format: <interval>,<probability>,<space>,<times>
			See also /Documentation/fault-injection/.

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	fd_mcs=		[HW,SCSI]
			See header of drivers/scsi/fd_mcs.c.

	fdomain=	[HW,SCSI]
			See header of drivers/scsi/fdomain.c.

	floppy=		[HW]
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			See Documentation/blockdev/floppy.txt.
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	force_pal_cache_flush
			[IA-64] Avoid check_sal_cache_flush which may hang on
			buggy SAL_CACHE_FLUSH implementations. Using this
			parameter will force ia64_sal_cache_flush to call
			ia64_pal_cache_flush instead of SAL_CACHE_FLUSH.

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	ftrace=[tracer]
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			[FTRACE] will set and start the specified tracer
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			as early as possible in order to facilitate early
			boot debugging.

	ftrace_dump_on_oops
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			[FTRACE] will dump the trace buffers on oops.

	ftrace_filter=[function-list]
			[FTRACE] Limit the functions traced by the function
			tracer at boot up. function-list is a comma separated
			list of functions. This list can be changed at run
			time by the set_ftrace_filter file in the debugfs
			tracing directory. 

	ftrace_notrace=[function-list]
			[FTRACE] Do not trace the functions specified in
			function-list. This list can be changed at run time
			by the set_ftrace_notrace file in the debugfs
			tracing directory.
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	ftrace_graph_filter=[function-list]
			[FTRACE] Limit the top level callers functions traced
			by the function graph tracer at boot up.
			function-list is a comma separated list of functions
			that can be changed at run time by the
			set_graph_function file in the debugfs tracing directory.

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	gamecon.map[2|3]=
			[HW,JOY] Multisystem joystick and NES/SNES/PSX pad
			support via parallel port (up to 5 devices per port)
			Format: <port#>,<pad1>,<pad2>,<pad3>,<pad4>,<pad5>
			See also Documentation/input/joystick-parport.txt

	gamma=		[HW,DRM]

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	gart_fix_e820=  [X86_64] disable the fix e820 for K8 GART
			Format: off | on
			default: on

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	gcov_persist=	[GCOV] When non-zero (default), profiling data for
			kernel modules is saved and remains accessible via
			debugfs, even when the module is unloaded/reloaded.
			When zero, profiling data is discarded and associated
			debugfs files are removed at module unload time.

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	gdth=		[HW,SCSI]
			See header of drivers/scsi/gdth.c.

	gpt		[EFI] Forces disk with valid GPT signature but
			invalid Protective MBR to be treated as GPT.

	gvp11=		[HW,SCSI]

	hashdist=	[KNL,NUMA] Large hashes allocated during boot
			are distributed across NUMA nodes.  Defaults on
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			for 64bit NUMA, off otherwise.
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			Format: 0 | 1 (for off | on)
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	hcl=		[IA-64] SGI's Hardware Graph compatibility layer

	hd=		[EIDE] (E)IDE hard drive subsystem geometry
			Format: <cyl>,<head>,<sect>

	highmem=nn[KMG]	[KNL,BOOT] forces the highmem zone to have an exact
			size of <nn>. This works even on boxes that have no
			highmem otherwise. This also works to reduce highmem
			size on bigger boxes.

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	highres=	[KNL] Enable/disable high resolution timer mode.
			Valid parameters: "on", "off"
			Default: "on"

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	hisax=		[HW,ISDN]
			See Documentation/isdn/README.HiSax.

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	hlt		[BUGS=ARM,SH]

	hpet=		[X86-32,HPET] option to control HPET usage
			Format: { enable (default) | disable | force |
				verbose }
			disable: disable HPET and use PIT instead
			force: allow force enabled of undocumented chips (ICH4,
				VIA, nVidia)
			verbose: show contents of HPET registers during setup

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	hugepages=	[HW,X86-32,IA-64] HugeTLB pages to allocate at boot.
	hugepagesz=	[HW,IA-64,PPC,X86-64] The size of the HugeTLB pages.
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			On x86-64 and powerpc, this option can be specified
			multiple times interleaved with hugepages= to reserve
			huge pages of different sizes. Valid pages sizes on
			x86-64 are 2M (when the CPU supports "pse") and 1G
			(when the CPU supports the "pdpe1gb" cpuinfo flag)
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			Note that 1GB pages can only be allocated at boot time
			using hugepages= and not freed afterwards.
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	hvc_iucv=	[S390] Number of z/VM IUCV hypervisor console (HVC)
			       terminal devices. Valid values: 0..8
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	hvc_iucv_allow=	[S390] Comma-separated list of z/VM user IDs.
			       If specified, z/VM IUCV HVC accepts connections
			       from listed z/VM user IDs only.
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	i2c_bus=	[HW] Override the default board specific I2C bus speed
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			     or register an additional I2C bus that is not
			     registered from board initialization code.
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			     Format:
			     <bus_id>,<clkrate>

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	i8042.debug	[HW] Toggle i8042 debug mode
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	i8042.direct	[HW] Put keyboard port into non-translated mode
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	i8042.dumbkbd	[HW] Pretend that controller can only read data from
			     keyboard and cannot control its state
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			     (Don't attempt to blink the leds)
	i8042.noaux	[HW] Don't check for auxiliary (== mouse) port
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	i8042.nokbd	[HW] Don't check/create keyboard port
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	i8042.noloop	[HW] Disable the AUX Loopback command while probing
			     for the AUX port
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	i8042.nomux	[HW] Don't check presence of an active multiplexing
			     controller
	i8042.nopnp	[HW] Don't use ACPIPnP / PnPBIOS to discover KBD/AUX
			     controllers
	i8042.panicblink=
			[HW] Frequency with which keyboard LEDs should blink
			     when kernel panics (default is 0.5 sec)
	i8042.reset	[HW] Reset the controller during init and cleanup
	i8042.unlock	[HW] Unlock (ignore) the keylock

	i810=		[HW,DRM]

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	i8k.ignore_dmi	[HW] Continue probing hardware even if DMI data
			indicates that the driver is running on unsupported
			hardware.
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	i8k.force	[HW] Activate i8k driver even if SMM BIOS signature
			does not match list of supported models.
	i8k.power_status
			[HW] Report power status in /proc/i8k
			(disabled by default)
	i8k.restricted	[HW] Allow controlling fans only if SYS_ADMIN
			capability is set.

	ibmmcascsi=	[HW,MCA,SCSI] IBM MicroChannel SCSI adapter
			See Documentation/mca.txt.

	icn=		[HW,ISDN]
			Format: <io>[,<membase>[,<icn_id>[,<icn_id2>]]]

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	ide-core.nodma=	[HW] (E)IDE subsystem
			Format: =0.0 to prevent dma on hda, =0.1 hdb =1.0 hdc
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			.vlb_clock .pci_clock .noflush .nohpa .noprobe .nowerr
			.cdrom .chs .ignore_cable are additional options
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			See Documentation/ide/ide.txt.
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	ide-pci-generic.all-generic-ide [HW] (E)IDE subsystem
			Claim all unknown PCI IDE storage controllers.

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	idle=		[X86]
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			Format: idle=poll, idle=mwait, idle=halt, idle=nomwait
			Poll forces a polling idle loop that can slightly
			improve the performance of waking up a idle CPU, but
			will use a lot of power and make the system run hot.
			Not recommended.
			idle=mwait: On systems which support MONITOR/MWAIT but
			the kernel chose to not use it because it doesn't save
			as much power as a normal idle loop, use the
			MONITOR/MWAIT idle loop anyways. Performance should be
			the same as idle=poll.
			idle=halt: Halt is forced to be used for CPU idle.
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			idle=nomwait: Disable mwait for CPU C-states
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	ignore_loglevel	[KNL]
			Ignore loglevel setting - this will print /all/
			kernel messages to the console. Useful for debugging.

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	ihash_entries=	[KNL]
			Set number of hash buckets for inode cache.

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	ima_audit=	[IMA]
			Format: { "0" | "1" }
			0 -- integrity auditing messages. (Default)
			1 -- enable informational integrity auditing messages.

	ima_hash=	[IMA]
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			Format: { "sha1" | "md5" }
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			default: "sha1"

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	ima_tcb		[IMA]
			Load a policy which meets the needs of the Trusted
			Computing Base.  This means IMA will measure all
			programs exec'd, files mmap'd for exec, and all files
			opened for read by uid=0.

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	in2000=		[HW,SCSI]
			See header of drivers/scsi/in2000.c.

	init=		[KNL]
			Format: <full_path>
			Run specified binary instead of /sbin/init as init
			process.

	initcall_debug	[KNL] Trace initcalls as they are executed.  Useful
			for working out where the kernel is dying during
			startup.

	initrd=		[BOOT] Specify the location of the initial ramdisk

	inport.irq=	[HW] Inport (ATI XL and Microsoft) busmouse driver
			Format: <irq>

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	intel_iommu=	[DMAR] Intel IOMMU driver (DMAR) option
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		on
			Enable intel iommu driver.
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		off
			Disable intel iommu driver.
		igfx_off [Default Off]
			By default, gfx is mapped as normal device. If a gfx
			device has a dedicated DMAR unit, the DMAR unit is
			bypassed by not enabling DMAR with this option. In
			this case, gfx device will use physical address for
			DMA.
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		forcedac [x86_64]
			With this option iommu will not optimize to look
			for io virtual address below 32 bit forcing dual
			address cycle on pci bus for cards supporting greater
			than 32 bit addressing. The default is to look
			for translation below 32 bit and if not available
			then look in the higher range.
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		strict [Default Off]
			With this option on every unmap_single operation will
			result in a hardware IOTLB flush operation as opposed
			to batching them for performance.
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	inttest=	[IA64]

	iomem=		Disable strict checking of access to MMIO memory
		strict	regions from userspace.
		relaxed

	iommu=		[x86]
		off
		force
		noforce
		biomerge
		panic
		nopanic
		merge
		nomerge
		forcesac
		soft
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		pt	[x86, IA64]
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	io7=		[HW] IO7 for Marvel based alpha systems
			See comment before marvel_specify_io7 in
			arch/alpha/kernel/core_marvel.c.

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	io_delay=	[X86] I/O delay method
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		0x80
			Standard port 0x80 based delay
		0xed
			Alternate port 0xed based delay (needed on some systems)
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		udelay
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			Simple two microseconds delay
		none
			No delay
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	ip=		[IP_PNP]
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			See Documentation/filesystems/nfsroot.txt.
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	ip2=		[HW] Set IO/IRQ pairs for up to 4 IntelliPort boards
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			See comment before ip2_setup() in
			drivers/char/ip2/ip2base.c.
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	ips=		[HW,SCSI] Adaptec / IBM ServeRAID controller
			See header of drivers/scsi/ips.c.

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	irqfixup	[HW]
			When an interrupt is not handled search all handlers
			for it. Intended to get systems with badly broken
			firmware running.

	irqpoll		[HW]
			When an interrupt is not handled search all handlers
			for it. Also check all handlers each timer
			interrupt. Intended to get systems with badly broken
			firmware running.

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	isapnp=		[ISAPNP]
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			Format: <RDP>,<reset>,<pci_scan>,<verbosity>
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	isolcpus=	[KNL,SMP] Isolate CPUs from the general scheduler.
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			Format:
			<cpu number>,...,<cpu number>
			or
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			<cpu number>-<cpu number>
			(must be a positive range in ascending order)
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			or a mixture
			<cpu number>,...,<cpu number>-<cpu number>
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			This option can be used to specify one or more CPUs
			to isolate from the general SMP balancing and scheduling
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			algorithms. You can move a process onto or off an
			"isolated" CPU via the CPU affinity syscalls or cpuset.
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			<cpu number> begins at 0 and the maximum value is
			"number of CPUs in system - 1".

			This option is the preferred way to isolate CPUs. The
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			alternative -- manually setting the CPU mask of all
			tasks in the system -- can cause problems and
			suboptimal load balancer performance.
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	iucv=		[HW,NET]
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	js=		[HW,JOY] Analog joystick
			See Documentation/input/joystick.txt.

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	keepinitrd	[HW,ARM]

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	kernelcore=nn[KMG]	[KNL,X86,IA-64,PPC] This parameter
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			specifies the amount of memory usable by the kernel
			for non-movable allocations.  The requested amount is
			spread evenly throughout all nodes in the system. The
			remaining memory in each node is used for Movable
			pages. In the event, a node is too small to have both
			kernelcore and Movable pages, kernelcore pages will
			take priority and other nodes will have a larger number
			of kernelcore pages.  The Movable zone is used for the
			allocation of pages that may be reclaimed or moved
			by the page migration subsystem.  This means that
			HugeTLB pages may not be allocated from this zone.
			Note that allocations like PTEs-from-HighMem still
			use the HighMem zone if it exists, and the Normal
			zone if it does not.

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	kgdboc=		[HW] kgdb over consoles.
			Requires a tty driver that supports console polling.
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			(only serial supported for now)
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			Format: <serial_device>[,baud]

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	kmac=		[MIPS] korina ethernet MAC address.
			Configure the RouterBoard 532 series on-chip
			Ethernet adapter MAC address.

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	kmemleak=	[KNL] Boot-time kmemleak enable/disable
			Valid arguments: on, off
			Default: on

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	kstack=N	[X86] Print N words from the kernel stack
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			in oops dumps.

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	kvm.ignore_msrs=[KVM] Ignore guest accesses to unhandled MSRs.
			Default is 0 (don't ignore, but inject #GP)

	kvm.oos_shadow=	[KVM] Disable out-of-sync shadow paging.
			Default is 1 (enabled)

	kvm-amd.nested=	[KVM,AMD] Allow nested virtualization in KVM/SVM.
			Default is 0 (off)

	kvm-amd.npt=	[KVM,AMD] Disable nested paging (virtualized MMU)
			for all guests.
			Default is 1 (enabled) if in 64bit or 32bit-PAE mode

	kvm-intel.bypass_guest_pf=
			[KVM,Intel] Disables bypassing of guest page faults
			on Intel chips. Default is 1 (enabled)

	kvm-intel.ept=	[KVM,Intel] Disable extended page tables
			(virtualized MMU) support on capable Intel chips.
			Default is 1 (enabled)

	kvm-intel.emulate_invalid_guest_state=
			[KVM,Intel] Enable emulation of invalid guest states
			Default is 0 (disabled)

	kvm-intel.flexpriority=
			[KVM,Intel] Disable FlexPriority feature (TPR shadow).
			Default is 1 (enabled)

	kvm-intel.unrestricted_guest=
			[KVM,Intel] Disable unrestricted guest feature
			(virtualized real and unpaged mode) on capable
			Intel chips. Default is 1 (enabled)

	kvm-intel.vpid=	[KVM,Intel] Disable Virtual Processor Identification
			feature (tagged TLBs) on capable Intel chips.
			Default is 1 (enabled)

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	l2cr=		[PPC]

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	l3cr=		[PPC]

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	lapic		[X86-32,APIC] Enable the local APIC even if BIOS
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			disabled it.
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	lapic_timer_c2_ok	[X86,APIC] trust the local apic timer
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			in C2 power state.
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	libata.dma=	[LIBATA] DMA control
			libata.dma=0	  Disable all PATA and SATA DMA
			libata.dma=1	  PATA and SATA Disk DMA only
			libata.dma=2	  ATAPI (CDROM) DMA only
			libata.dma=4	  Compact Flash DMA only 
			Combinations also work, so libata.dma=3 enables DMA
			for disks and CDROMs, but not CFs.
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	libata.ignore_hpa=	[LIBATA] Ignore HPA limit
			libata.ignore_hpa=0	  keep BIOS limits (default)
			libata.ignore_hpa=1	  ignore limits, using full disk
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	libata.noacpi	[LIBATA] Disables use of ACPI in libata suspend/resume
			when set.
			Format: <int>

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	libata.force=	[LIBATA] Force configurations.  The format is comma
			separated list of "[ID:]VAL" where ID is
			PORT[:DEVICE].  PORT and DEVICE are decimal numbers
			matching port, link or device.  Basically, it matches
			the ATA ID string printed on console by libata.  If
			the whole ID part is omitted, the last PORT and DEVICE
			values are used.  If ID hasn't been specified yet, the
			configuration applies to all ports, links and devices.

			If only DEVICE is omitted, the parameter applies to
			the port and all links and devices behind it.  DEVICE
			number of 0 either selects the first device or the
			first fan-out link behind PMP device.  It does not
			select the host link.  DEVICE number of 15 selects the
			host link and device attached to it.

			The VAL specifies the configuration to force.  As long
			as there's no ambiguity shortcut notation is allowed.
			For example, both 1.5 and 1.5G would work for 1.5Gbps.
			The following configurations can be forced.

			* Cable type: 40c, 80c, short40c, unk, ign or sata.
			  Any ID with matching PORT is used.

			* SATA link speed limit: 1.5Gbps or 3.0Gbps.

			* Transfer mode: pio[0-7], mwdma[0-4] and udma[0-7].
			  udma[/][16,25,33,44,66,100,133] notation is also
			  allowed.

			* [no]ncq: Turn on or off NCQ.

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			* nohrst, nosrst, norst: suppress hard, soft
                          and both resets.

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			If there are multiple matching configurations changing
			the same attribute, the last one is used.

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	lmb=debug	[KNL] Enable lmb debug messages.

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	load_ramdisk=	[RAM] List of ramdisks to load from floppy
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			See Documentation/blockdev/ramdisk.txt.
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	lockd.nlm_grace_period=P  [NFS] Assign grace period.
			Format: <integer>
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	lockd.nlm_tcpport=N	[NFS] Assign TCP port.
			Format: <integer>

	lockd.nlm_timeout=T	[NFS] Assign timeout value.
			Format: <integer>

	lockd.nlm_udpport=M	[NFS] Assign UDP port.
			Format: <integer>
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	logibm.irq=	[HW,MOUSE] Logitech Bus Mouse Driver
			Format: <irq>

	loglevel=	All Kernel Messages with a loglevel smaller than the
			console loglevel will be printed to the console. It can
			also be changed with klogd or other programs. The
			loglevels are defined as follows:

			0 (KERN_EMERG)		system is unusable
			1 (KERN_ALERT)		action must be taken immediately
			2 (KERN_CRIT)		critical conditions
			3 (KERN_ERR)		error conditions
			4 (KERN_WARNING)	warning conditions
			5 (KERN_NOTICE)		normal but significant condition
			6 (KERN_INFO)		informational
			7 (KERN_DEBUG)		debug-level messages

	log_buf_len=n	Sets the size of the printk ring buffer, in bytes.
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			Format: { n | nk | nM }
			n must be a power of two.  The default size
			is set in the kernel config file.
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	logo.nologo	[FB] Disables display of the built-in Linux logo.
			This may be used to provide more screen space for
			kernel log messages and is useful when debugging
			kernel boot problems.

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	lp=0		[LP]	Specify parallel ports to use, e.g,
	lp=port[,port...]	lp=none,parport0 (lp0 not configured, lp1 uses
	lp=reset		first parallel port). 'lp=0' disables the
	lp=auto			printer driver. 'lp=reset' (which can be
				specified in addition to the ports) causes
				attached printers to be reset. Using
				lp=port1,port2,... specifies the parallel ports
				to associate lp devices with, starting with
				lp0. A port specification may be 'none' to skip
				that lp device, or a parport name such as
				'parport0'. Specifying 'lp=auto' instead of a
				port specification list means that device IDs
				from each port should be examined, to see if
				an IEEE 1284-compliant printer is attached; if
				so, the driver will manage that printer.
				See also header of drivers/char/lp.c.

	lpj=n		[KNL]
			Sets loops_per_jiffy to given constant, thus avoiding
			time-consuming boot-time autodetection (up to 250 ms per
			CPU). 0 enables autodetection (default). To determine
			the correct value for your kernel, boot with normal
			autodetection and see what value is printed. Note that
			on SMP systems the preset will be applied to all CPUs,
			which is likely to cause problems if your CPUs need
			significantly divergent settings. An incorrect value
			will cause delays in the kernel to be wrong, leading to
			unpredictable I/O errors and other breakage. Although
			unlikely, in the extreme case this might damage your
			hardware.

	ltpc=		[NET]
			Format: <io>,<irq>,<dma>

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	mac5380=	[HW,SCSI] Format:
			<can_queue>,<cmd_per_lun>,<sg_tablesize>,<hostid>,<use_tags>
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	machvec=	[IA64] Force the use of a particular machine-vector
			(machvec) in a generic kernel.
			Example: machvec=hpzx1_swiotlb
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	machtype=	[Loongson] Share the same kernel image file between different
			 yeeloong laptop.
			Example: machtype=lemote-yeeloong-2f-7inch

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	max_addr=nn[KMG]	[KNL,BOOT,ia64] All physical memory greater
			than or equal to this physical address is ignored.
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	maxcpus=	[SMP] Maximum number of processors that	an SMP kernel
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			should make use of.  maxcpus=n : n >= 0 limits the
			kernel to using 'n' processors.  n=0 is a special case,
			it is equivalent to "nosmp", which also disables
			the IO APIC.
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	max_loop=	[LOOP] Maximum number of loopback devices that can
			be mounted
			Format: <1-256>
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	max_luns=	[SCSI] Maximum number of LUNs to probe.
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			Should be between 1 and 2^32-1.

	max_report_luns=
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			[SCSI] Maximum number of LUNs received.
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			Should be between 1 and 16384.

	mcatest=	[IA-64]

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	mce		[X86-32] Machine Check Exception
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	mce=option	[X86-64] See Documentation/x86/x86_64/boot-options.txt
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	md=		[HW] RAID subsystems devices and level
			See Documentation/md.txt.
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	mdacon=		[MDA]
			Format: <first>,<last>
			Specifies range of consoles to be captured by the MDA.
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	mem=nn[KMG]	[KNL,BOOT] Force usage of a specific amount of memory
			Amount of memory to be used when the kernel is not able
			to see the whole system memory or for test.
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			[X86-32] Use together with memmap= to avoid physical
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			address space collisions. Without memmap= PCI devices
			could be placed at addresses belonging to unused RAM.

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	mem=nopentium	[BUGS=X86-32] Disable usage of 4MB pages for kernel
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			memory.

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	memchunk=nn[KMG]
			[KNL,SH] Allow user to override the default size for
			per-device physically contiguous DMA buffers.

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	memmap=exactmap	[KNL,X86] Enable setting of an exact
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			E820 memory map, as specified by the user.
			Such memmap=exactmap lines can be constructed based on
			BIOS output or other requirements. See the memmap=nn@ss
			option description.

	memmap=nn[KMG]@ss[KMG]
			[KNL] Force usage of a specific region of memory
			Region of memory to be used, from ss to ss+nn.

	memmap=nn[KMG]#ss[KMG]
			[KNL,ACPI] Mark specific memory as ACPI data.
			Region of memory to be used, from ss to ss+nn.

	memmap=nn[KMG]$ss[KMG]
			[KNL,ACPI] Mark specific memory as reserved.
			Region of memory to be used, from ss to ss+nn.
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			Example: Exclude memory from 0x18690000-0x1869ffff
			         memmap=64K$0x18690000
			         or
			         memmap=0x10000$0x18690000
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	memory_corruption_check=0/1 [X86]
			Some BIOSes seem to corrupt the first 64k of
			memory when doing things like suspend/resume.
			Setting this option will scan the memory
			looking for corruption.  Enabling this will
			both detect corruption and prevent the kernel
			from using the memory being corrupted.
			However, its intended as a diagnostic tool; if
			repeatable BIOS-originated corruption always
			affects the same memory, you can use memmap=
			to prevent the kernel from using that memory.

	memory_corruption_check_size=size [X86]
			By default it checks for corruption in the low
			64k, making this memory unavailable for normal
			use.  Use this parameter to scan for
			corruption in more or less memory.

	memory_corruption_check_period=seconds [X86]
			By default it checks for corruption every 60
			seconds.  Use this parameter to check at some
			other rate.  0 disables periodic checking.

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	memtest=	[KNL,X86] Enable memtest
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			Format: <integer>
			default : 0 <disable>
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			Specifies the number of memtest passes to be
			performed. Each pass selects another test
			pattern from a given set of patterns. Memtest
			fills the memory with this pattern, validates
			memory contents and reserves bad memory
			regions that are detected.
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	meye.*=		[HW] Set MotionEye Camera parameters
			See Documentation/video4linux/meye.txt.

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	mfgpt_irq=	[IA-32] Specify the IRQ to use for the
			Multi-Function General Purpose Timers on AMD Geode
			platforms.

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	mfgptfix	[X86-32] Fix MFGPT timers on AMD Geode platforms when
			the BIOS has incorrectly applied a workaround. TinyBIOS
			version 0.98 is known to be affected, 0.99 fixes the
			problem by letting the user disable the workaround.

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	mga=		[HW,DRM]

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	min_addr=nn[KMG]	[KNL,BOOT,ia64] All physical memory below this
			physical address is ignored.

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	mini2440=	[ARM,HW,KNL]
			Format:[0..2][b][c][t]
			Default: "0tb"
			MINI2440 configuration specification:
			0 - The attached screen is the 3.5" TFT
			1 - The attached screen is the 7" TFT
			2 - The VGA Shield is attached (1024x768)
			Leaving out the screen size parameter will not load
			the TFT driver, and the framebuffer will be left
			unconfigured.
			b - Enable backlight. The TFT backlight pin will be
			linked to the kernel VESA blanking code and a GPIO
			LED. This parameter is not necessary when using the
			VGA shield.
			c - Enable the s3c camera interface.
			t - Reserved for enabling touchscreen support. The
			touchscreen support is not enabled in the mainstream
			kernel as of 2.6.30, a preliminary port can be found
			in the "bleeding edge" mini2440 support kernel at
			http://repo.or.cz/w/linux-2.6/mini2440.git

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	mminit_loglevel=
			[KNL] When CONFIG_DEBUG_MEMORY_INIT is set, this
			parameter allows control of the logging verbosity for
			the additional memory initialisation checks. A value
			of 0 disables mminit logging and a level of 4 will
			log everything. Information is printed at KERN_DEBUG
			so loglevel=8 may also need to be specified.

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	mousedev.tap_time=
			[MOUSE] Maximum time between finger touching and
			leaving touchpad surface for touch to be considered
			a tap and be reported as a left button click (for
			touchpads working in absolute mode only).
			Format: <msecs>
	mousedev.xres=	[MOUSE] Horizontal screen resolution, used for devices
			reporting absolute coordinates, such as tablets
	mousedev.yres=	[MOUSE] Vertical screen resolution, used for devices
			reporting absolute coordinates, such as tablets

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	movablecore=nn[KMG]	[KNL,X86,IA-64,PPC] This parameter
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			is similar to kernelcore except it specifies the
			amount of memory used for migratable allocations.
			If both kernelcore and movablecore is specified,
			then kernelcore will be at *least* the specified
			value but may be more. If movablecore on its own
			is specified, the administrator must be careful
			that the amount of memory usable for all allocations
			is not too small.

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	mpu401=		[HW,OSS]
			Format: <io>,<irq>

	MTD_Partition=	[MTD]
			Format: <name>,<region-number>,<size>,<offset>

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	MTD_Region=	[MTD] Format:
			<name>,<region-number>[,<base>,<size>,<buswidth>,<altbuswidth>]
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	mtdparts=	[MTD]
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			See drivers/mtd/cmdlinepart.c.
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	onenand.bdry=	[HW,MTD] Flex-OneNAND Boundary Configuration

			Format: [die0_boundary][,die0_lock][,die1_boundary][,die1_lock]

			boundary - index of last SLC block on Flex-OneNAND.
				   The remaining blocks are configured as MLC blocks.
			lock	 - Configure if Flex-OneNAND boundary should be locked.
				   Once locked, the boundary cannot be changed.
				   1 indicates lock status, 0 indicates unlock status.

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	mtdset=		[ARM]
			ARM/S3C2412 JIVE boot control

			See arch/arm/mach-s3c2412/mach-jive.c

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	mtouchusb.raw_coordinates=
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			[HW] Make the MicroTouch USB driver use raw coordinates
			('y', default) or cooked coordinates ('n')
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	mtrr_chunk_size=nn[KMG] [X86]
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			used for mtrr cleanup. It is largest continuous chunk
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			that could hold holes aka. UC entries.

	mtrr_gran_size=nn[KMG] [X86]
			Used for mtrr cleanup. It is granularity of mtrr block.
			Default is 1.
			Large value could prevent small alignment from
			using up MTRRs.

	mtrr_spare_reg_nr=n [X86]
			Format: <integer>
			Range: 0,7 : spare reg number
			Default : 1
			Used for mtrr cleanup. It is spare mtrr entries number.
			Set to 2 or more if your graphical card needs more.

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	n2=		[NET] SDL Inc. RISCom/N2 synchronous serial card

	NCR_D700=	[HW,SCSI]
			See header of drivers/scsi/NCR_D700.c.

	ncr5380=	[HW,SCSI]

	ncr53c400=	[HW,SCSI]

	ncr53c400a=	[HW,SCSI]

	ncr53c406a=	[HW,SCSI]

	ncr53c8xx=	[HW,SCSI]

	netdev=		[NET] Network devices parameters
			Format: <irq>,<io>,<mem_start>,<mem_end>,<name>
			Note that mem_start is often overloaded to mean
			something different and driver-specific.
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			This usage is only documented in each driver source
			file if at all.

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	nf_conntrack.acct=
			[NETFILTER] Enable connection tracking flow accounting
			0 to disable accounting
			1 to enable accounting
			Default value depends on CONFIG_NF_CT_ACCT that is
			going to be removed in 2.6.29.

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	nfsaddrs=	[NFS]
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			See Documentation/filesystems/nfsroot.txt.
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	nfsroot=	[NFS] nfs root filesystem for disk-less boxes.
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			See Documentation/filesystems/nfsroot.txt.
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	nfs.callback_tcpport=
			[NFS] set the TCP port on which the NFSv4 callback
			channel should listen.

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	nfs.cache_getent=
			[NFS] sets the pathname to the program which is used
			to update the NFS client cache entries.

	nfs.cache_getent_timeout=
			[NFS] sets the timeout after which an attempt to
			update a cache entry is deemed to have failed.

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	nfs.idmap_cache_timeout=
			[NFS] set the maximum lifetime for idmapper cache
			entries.

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	nfs.enable_ino64=
			[NFS] enable 64-bit inode numbers.
			If zero, the NFS client will fake up a 32-bit inode
			number for the readdir() and stat() syscalls instead
			of returning the full 64-bit number.
			The default is to return 64-bit inode numbers.

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	nmi_debug=	[KNL,AVR32,SH] Specify one or more actions to take
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			when a NMI is triggered.
			Format: [state][,regs][,debounce][,die]

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	nmi_watchdog=	[KNL,BUGS=X86] Debugging features for SMP kernels
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			Format: [panic,][num]
			Valid num: 0,1,2
			0 - turn nmi_watchdog off
			1 - use the IO-APIC timer for the NMI watchdog
			2 - use the local APIC for the NMI watchdog using
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			a performance counter. Note: This will use one
			performance counter and the local APIC's performance
			vector.
			When panic is specified, panic when an NMI watchdog
			timeout occurs.
			This is useful when you use a panic=... timeout and
			need the box quickly up again.
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			Instead of 1 and 2 it is possible to use the following
			symbolic names: lapic and ioapic
			Example: nmi_watchdog=2 or nmi_watchdog=panic,lapic
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	netpoll.carrier_timeout=
			[NET] Specifies amount of time (in seconds) that
			netpoll should wait for a carrier. By default netpoll
			waits 4 seconds.

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	no387		[BUGS=X86-32] Tells the kernel to use the 387 maths
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			emulation library even if a 387 maths coprocessor
			is present.

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	no_console_suspend
			[HW] Never suspend the console
			Disable suspending of consoles during suspend and
			hibernate operations.  Once disabled, debugging
			messages can reach various consoles while the rest
			of the system is being put to sleep (ie, while
			debugging driver suspend/resume hooks).  This may
			not work reliably with all consoles, but is known
			to work with serial and VGA consoles.

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	noaliencache	[MM, NUMA, SLAB] Disables the allocation of alien
			caches in the slab allocator.  Saves per-node memory,
			but will impact performance.
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	noalign		[KNL,ARM]

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