Documentation/kernel-parameters.txt

February 2003             Kernel Parameters                     v2.5.59
                          ~~~~~~~~~~~~~~~~~

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.

The text in square brackets at the beginning of the description state the
restrictions on the kernel for the said kernel parameter to be valid. The
restrictions referred to are that the relevant option is valid if:

	ACPI	ACPI support is enabled.
	ALSA	ALSA sound support is enabled.
	APIC	APIC support is enabled.
	APM	Advanced Power Management support is enabled.
	AX25	Appropriate AX.25 support is enabled.
	CD	Appropriate CD support is enabled.
	DEVFS	devfs support is enabled. 
	DRM	Direct Rendering Management support is enabled. 
	EFI	EFI Partitioning (GPT) is enabled
	EIDE	EIDE/ATAPI support is enabled.
	FB	The frame buffer device is enabled.
	HW	Appropriate hardware is enabled.
	IA-32	IA-32 aka i386 architecture is enabled.
	IA-64	IA-64 architecture is enabled.
	IOSCHED	More than one I/O scheduler is enabled.
	IP_PNP	IP DCHP, BOOTP, or RARP is enabled.
	ISAPNP	ISA PnP code is enabled.
	ISDN	Appropriate ISDN support is enabled.
	JOY	Appropriate joystick support is enabled.
	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.
	MTD	MTD support is enabled.
	NET	Appropriate network support is enabled.
	NFS	Appropriate NFS support is enabled.
	OSS	OSS sound support is enabled.
	PARIDE	The ParIDE subsystem is enabled.
	PCI	PCI bus support is enabled.
	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/.
	SERIAL	Serial support is enabled.
	SMP	The kernel is an SMP kernel.
	SPARC	Sparc architecture is enabled.
	SWSUSP	Software suspension is enabled.
	TS	Appropriate touchscreen support is enabled.
	USB	USB 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.

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
need or coordination with <Documentation/i386/boot.txt>.

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.

	53c7xx=		[HW,SCSI] Amiga SCSI controllers
			See header of drivers/scsi/53c7xx.c.
			See also Documentation/scsi/ncr53c7xx.txt.

	98busmouse.irq=	[HW,MOUSE] PC-9801 Bus Mouse Driver
			Format: <irq>, default is 13

	acpi=		[HW,ACPI] Advanced Configuration and Power Interface 
			Format: { force | off | ht | strict }
			force -- enables ACPI for systems with default off
			off -- disabled ACPI for systems with default on
			ht -- run only enough ACPI to enable Hyper Threading
			strict --  Be less tolerant of platforms that are not
				strictly ACPI specification compliant.

			See also Documentation/pm.txt.

	acpi_sleep=	[HW,ACPI] Sleep options
			Format: { s3_bios, s3_mode }
			See Documentation/power/video.txt
 
	acpi_pic_sci=	[HW,ACPI] ACPI System Control Interrupt trigger mode
			Format: { level | edge }
			level   Force PIC-mode SCI to Level Trigger (default)
			edge    Force PIC-mode SCI to Edge Trigge

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

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

	acpi_osi=	[HW,ACPI] empty param disables _OSI

	acpi_serialize	[HW,ACPI] force serialization of AML methods

	ad1816=		[HW,OSS]
			Format: <io>,<irq>,<dma>,<dma2>
			See also Documentation/sound/oss/AD1816.

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

	adlib=		[HW,OSS]
			Format: <io>
 
	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.
 
	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.

	allowdma0	[ISAPNP]

	AM53C974=	[HW,SCSI]
			Format: <host-scsi-id>,<target-scsi-id>,<max-rate>,<max-offset>
			See also header of drivers/scsi/AM53C974.c.

	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>

	apc=		[HW,SPARC] Power management functions (SPARCstation-4/5 + deriv.)
			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.
 
	apm=		[APM] Advanced Power Management
			See header of arch/i386/kernel/apm.c.

	applicom=	[HW]
			Format: <mem>,<irq>
 
	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

	atkbd.set=	[HW] Select keyboard code set 
			Format: <int> (2 = AT (default) 3 = PS/2)

	atkbd.scroll=	[HW] Enable scroll wheel on MS Office and similar keyboards
	
	atkbd.softrepeat=
			[HW] Use software keyboard repeat

	autotest	[IA64]

	awe=		[HW,OSS] AWE32/SB32/AWE64 wave table synth
			Format: <io>,<memsize>,<isapnp>
 
	aztcd=		[HW,CD] Aztech CD268 CDROM driver
			Format: <io>,0x79 (?)

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

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

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

	blkmtd_device=	[HW,MTD]
	blkmtd_erasesz=
	blkmtd_ro=
	blkmtd_bs=
	blkmtd_count=

	bttv.card=	[HW,V4L] bttv (bt848 + bt878 based grabber cards)
	bttv.radio=	Most important insmod options are available as kernel args too.
	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

	cachesize=	[BUGS=IA-32] Override level 2 CPU cache size detection.
			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.

	cdu31a=		[HW,CD]
			Format: <io>,<irq>[,PAS]
			See header of drivers/cdrom/cdu31a.c.

	chandev=	[HW,NET] Generic channel device initialisation
 
 	clock=		[BUGS=IA-32, HW] gettimeofday timesource override. 
			Forces specified timesource (if avaliable) to be used
			when calculating gettimeofday(). If specicified timesource
			is not avalible, it defaults to PIT. 
			Format: { pit | tsc | cyclone | pmtmr }

	hpet=		[IA-32,HPET] option to disable HPET and use PIT.
			Format: disable

	cm206=		[HW,CD]
			Format: { auto | [<io>,][<irq>] }

	com20020=	[HW,NET] ARCnet - COM20020 chipset
			Format: <io>[,<irq>[,<nodeID>[,<backplane>[,<ckp>[,<timeout>]]]]]

	com90io=	[HW,NET] ARCnet - COM90xx chipset (IO-mapped buffers)
			Format: <io>[,<irq>]

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

	condev=		[HW,S390] console device
	conmode=
 
	console=	[KNL] Output console
			Console device and comm spec (speed, control, parity).

	cpcihp_generic=	[HW,PCI] Generic port I/O CompactPCI driver
			Format: <first_slot>,<last_slot>,<port>,<enum_bit>[,<debug>]

	cpia_pp=	[HW,PPT]
			Format: { parport<nr> | auto | none }

	cs4232=		[HW,OSS]
			Format: <io>,<irq>,<dma>,<dma2>,<mpuio>,<mpuirq>

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

	cs89x0_media=	[HW,NET]
			Format: { rj45 | aui | bnc }
 
	cyclades=	[HW,SERIAL] Cyclades multi-serial port adapter.
 
	dasd=		[HW,NET]    
			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).

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

	devfs=		[DEVFS]
			See Documentation/filesystems/devfs/boot-options.

	dhash_entries=	[KNL]
			Set number of hash buckets for dentry cache.
 
	digi=		[HW,SERIAL]
			IO parameters + enable/disable command.

	digiepca=	[HW,SERIAL]
			See drivers/char/README.epca and
			Documentation/digiepca.txt.

	dmascc=		[HW,AX25,SERIAL] AX.25 Z80SCC driver with DMA
			support available.
			Format: <io_dev0>[,<io_dev1>[,..<io_dev32>]]

	dmasound=	[HW,OSS] Sound subsystem buffers

	dscc4.setup=	[NET]

	dtc3181e=	[HW,SCSI]

	earlyprintk=	[x86, x86_64]
			earlyprintk=vga
			earlyprintk=serial[,ttySn[,baudrate]]

			Append ,keep to not disable it when the real console
			takes over.

			Only vga or serial at a time, not both.

			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]

	eda=		[HW,PS2]

	edb=		[HW,PS2]

	eicon=		[HW,ISDN] 
			Format: <id>,<membase>,<irq>

	eisa_irq_edge=	[PARISC]
			See header of drivers/parisc/eisa.c.

	elanfreq=	[IA-32]
			See comment before function elanfreq_setup() in
			arch/i386/kernel/cpu/cpufreq/elanfreq.c.

	elevator=	[IOSCHED]
			Format: {"as"|"cfq"|"deadline"|"noop"}
			See Documentation/as-iosched.txt for details

	es1370=		[HW,OSS]
			Format: <lineout>[,<micbias>]
			See also header of sound/oss/es1370.c.

	es1371=		[HW,OSS]
			Format: <spdif>,[<nomix>,[<amplifier>]]
			See also header of sound/oss/es1371.c.
 
	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>]

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

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

	floppy=		[HW]
			See Documentation/floppy.txt.

	ftape=		[HW] Floppy Tape subsystem debugging options.
			See Documentation/ftape.txt.

	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]

	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.

	gscd=		[HW,CD]
			Format: <io>

	gt96100eth=	[NET] MIPS GT96100 Advanced Communication Controller

	gus=		[HW,OSS]
			Format: <io>,<irq>,<dma>,<dma16>
 
	gvp11=		[HW,SCSI]

	hcl=		[IA-64] SGI's Hardware Graph compatibility layer

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

	hd?=		[HW] (E)IDE subsystem
	hd?lun=		See Documentation/ide.txt.

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

	hugepages=	[HW,IA-32,IA-64] Maximal number of HugeTLB pages.

	noirqbalance	[IA-32,SMP,KNL] Disable kernel irq balancing

	i8042.direct	[HW] Put keyboard port into non-translated mode
	i8042.dumbkbd	[HW] Pretend that controlled can only read data from
			     keyboard and can not control its state
			     (Don't attempt to blink the leds)
	i8042.noaux	[HW] Don't check for auxiliary (== mouse) port
	i8042.nomux	[HW] Don't check presence of an active multiplexing
			     controller
	i8042.reset	[HW] Reset the controller during init and cleanup
	i8042.unlock	[HW] Unlock (ignore) the keylock

	i810=		[HW,DRM]

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

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

	ide?=		[HW] (E)IDE subsystem
			Config (iomem/irq), tuning or debugging
			(serialize,reset,no{dma,tune,probe}) or chipset
			specific parameters.
			See Documentation/ide.txt.
	
	idebus=		[HW] (E)IDE subsystem - VLB/PCI bus speed
			See Documentation/ide.txt.

	idle=		[HW]
			Format: idle=poll or idle=halt
 
	ihash_entries=	[KNL]
			Set number of hash buckets for inode cache.

	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>

	inttest=	[IA64]

	io7=		[HW] IO7 for Marvel based alpha systems
			See comment before marvel_specify_io7 in
			arch/alpha/kernel/core_marvel.c.

	ip=		[IP_PNP]
			See Documentation/nfsroot.txt.

	ip2=		[HW] Set IO/IRQ pairs for up to 4 IntelliPort boards
			See comment before ip2_setup() in drivers/char/ip2.c.

	ips=		[HW,SCSI] Adaptec / IBM ServeRAID controller
			See header of drivers/scsi/ips.c.

	isapnp=		[ISAPNP]
			Format: <RDP>, <reset>, <pci_scan>, <verbosity>

	isp16=		[HW,CD]
			Format: <io>,<irq>,<dma>,<setup>

	iucv=		[HW,NET] 

	js=		[HW,JOY] Analog joystick
			See Documentation/input/joystick.txt.

	keepinitrd	[HW,ARM]

	l2cr=		[PPC]

	lapic		[IA-32,APIC] Enable the local APIC even if BIOS disabled it.

	lasi=		[HW,SCSI] PARISC LASI driver for the 53c700 chip
			Format: addr:<io>,irq:<irq>

	llsc*=		[IA64]
			See function print_params() in arch/ia64/sn/kernel/llsc4.c.

	load_ramdisk=	[RAM] List of ramdisks to load from floppy
			See Documentation/ramdisk.txt.

	lockd.udpport=	[NFS]

	lockd.tcpport=	[NFS]

	logibm.irq=	[HW,MOUSE] Logitech Bus Mouse Driver
			Format: <irq>

	log_buf_len=n	Sets the size of the printk ring buffer, in bytes.
			Format is n, nk, nM.  n must be a power of two.  The
			default is set in kernel config.

	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.

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

	mac5380=	[HW,SCSI]
			Format: <can_queue>,<cmd_per_lun>,<sg_tablesize>,<hostid>,<use_tags>

	mac53c9x=	[HW,SCSI]
			Format: <num_esps>,<disconnect>,<nosync>,<can_queue>,<cmd_per_lun>,<sg_tablesize>,<hostid>,<use_tags>
	
	mad16=		[HW,OSS]
			Format: <io>,<irq>,<dma>,<dma16>,<mpu_io>,<mpu_irq>,<joystick>

	maui=		[HW,OSS]
			Format: <io>,<irq>
 
	max_loop=       [LOOP] Maximum number of loopback devices that can
			be mounted
			Format: <1-256>

	maxcpus=	[SMP] Maximum number of processors that	an SMP kernel
			should make use of

	max_scsi_luns=	[SCSI]

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

	mca-pentium	[BUGS=IA-32]

	mcatest=	[IA-64]

	mcd=		[HW,CD]
			Format: <port>,<irq>,<mitsumi_bug_93_wait>

	mcdx=		[HW,CD]

	mce		[IA-32] Machine Check Exception

	md=		[HW] RAID subsystems devices and level
			See Documentation/md.txt.
 
	mdacon=		[MDA]
			Format: <first>,<last>
			Specifies range of consoles to be captured by the MDA.
 
	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.

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

	memmap=exactmap	[KNL,IA-32] Enable setting of an exact
			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.

	meye=		[HW] Set MotionEye Camera parameters
			See Documentation/video4linux/meye.txt.

	mga=		[HW,DRM]

	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

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

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

	MTD_Region=	[MTD]
			Format: <name>,<region-number>[,<base>,<size>,<buswidth>,<altbuswidth>]

	mtdparts=	[MTD]
			See drivers/mtd/cmdline.c.

	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.
 
	nfsaddrs=	[NFS]
			See Documentation/nfsroot.txt.

	nfsroot=	[NFS] nfs root filesystem for disk-less boxes.
			See Documentation/nfsroot.txt.

	nmi_watchdog=	[KNL,BUGS=IA-32] Debugging features for SMP kernels

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

	noalign		[KNL,ARM] 
 
	noapic		[SMP,APIC] Tells the kernel not to make use of any
			APIC that may be present on the system.

	noasync		[HW,M68K] Disables async and sync negotiation for
			all devices.

	nocache		[ARM]
 
	nodisconnect	[HW,SCSI,M68K] Disables SCSI disconnects.

	noexec		[IA-64]

	nofxsr		[BUGS=IA-32]

	nohighio	[BUGS=IA-32] Disable highmem block I/O.

	nohlt		[BUGS=ARM]
 
	no-hlt		[BUGS=IA-32] Tells the kernel that the hlt
			instruction doesn't work correctly and not to
			use it.

	noirqdebug	[IA-32] Disables the code which attempts to detect and
			disable unhandled interrupt sources.

	noisapnp	[ISAPNP] Disables ISA PnP code.

	noinitrd	[RAM] Tells the kernel not to load any configured
			initial RAM disk.

	nointroute	[IA-64]

	nolapic		[IA-32,APIC] Do not enable or use the local APIC.

	nomce		[IA-32] Machine Check Exception

	noresume	[SWSUSP] Disables resume and restore original swap space.
 
	no-scroll	[VGA] Disables scrollback.
			This is required for the Braillex ib80-piezo Braille
			reader made by F.H. Papenmeier (Germany).

	nosbagart	[IA-64]

	nosmp		[SMP] Tells an SMP kernel to act as a UP kernel.

	nosync		[HW,M68K] Disables sync negotiation for all devices.

	notsc		[BUGS=IA-32] Disable Time Stamp Counter

	nousb		[USB] Disable the USB subsystem

	nowb		[ARM]
 
	opl3=		[HW,OSS]
			Format: <io>

	opl3sa=		[HW,OSS]
			Format: <io>,<irq>,<dma>,<dma2>,<mpu_io>,<mpu_irq>

	opl3sa2=	[HW,OSS]
			Format: <io>,<irq>,<dma>,<dma2>,<mss_io>,<mpu_io>,<ymode>,<loopback>[,<isapnp>,<multiple]
 
	oprofile.timer=	[HW]
			Use timer interrupt instead of performance counters

	optcd=		[HW,CD]
			Format: <io>

	osst=		[HW,SCSI] SCSI Tape Driver
			Format: <buffer_size>,<write_threshold>
			See also Documentation/scsi/st.txt.

	panic=		[KNL] Kernel behaviour on panic
			Format: <timeout>

	parport=0	[HW,PPT]	Specify parallel ports. 0 disables.
	parport=auto			Use 'auto' to force the driver to use
	parport=0xBBB[,IRQ[,DMA]]	any IRQ/DMA settings detected (the
					default is to ignore detected IRQ/DMA
					settings because of possible
					conflicts). You can specify the base
					address, IRQ, and DMA settings; IRQ and
					DMA should be numbers, or 'auto' (for
					using detected settings on that
					particular port), or 'nofifo' (to avoid
					using a FIFO even if it is detected).
					Parallel ports are assigned in the
					order they are specified on the command
					line, starting with parport0.

	pas2=		[HW,OSS]
			Format: <io>,<irq>,<dma>,<dma16>,<sb_io>,<sb_irq>,<sb_dma>,<sb_dma16>
 
	pas16=		[HW,SCSI]
			See header of drivers/scsi/pas16.c.

	pcbit=		[HW,ISDN]

	pcd.		[PARIDE]
			See header of drivers/block/paride/pcd.c.
			See also Documentation/paride.txt.

	pci=option[,option...]		[PCI] various PCI subsystem options:
		off			[IA-32] don't probe for the PCI bus
		bios			[IA-32] force use of PCI BIOS, don't access
					the hardware directly. Use this if your machine
					has a non-standard PCI host bridge.
		nobios			[IA-32] disallow use of PCI BIOS, only direct
					hardware access methods are allowed. Use this
					if you experience crashes upon bootup and you
					suspect they are caused by the BIOS.
		conf1			[IA-32] Force use of PCI Configuration Mechanism 1.
		conf2			[IA-32] Force use of PCI Configuration Mechanism 2.
		nosort			[IA-32] Don't sort PCI devices according to
					order given by the PCI BIOS. This sorting is done
					to get a device order compatible with older kernels.
		biosirq			[IA-32] Use PCI BIOS calls to get the interrupt
					routing table. These calls are known to be buggy
					on several machines and they hang the machine when used,
					but on other computers it's the only way to get the
					interrupt routing table. Try this option if the kernel
					is unable to allocate IRQs or discover secondary PCI
					buses on your motherboard.
		rom			[IA-32] Assign address space to expansion ROMs.
					Use with caution as certain devices share address
					decoders between ROMs and other resources.
		irqmask=0xMMMM		[IA-32] Set a bit mask of IRQs allowed to be assigned
					automatically to PCI devices. You can make the kernel
					exclude IRQs of your ISA cards this way.
		lastbus=N		[IA-32] Scan all buses till bus #N. Can be useful
					if the kernel is unable to find your secondary buses
					and you want to tell it explicitly which ones they are.
		assign-busses		[IA-32] Always assign all PCI bus
					numbers ourselves, overriding
					whatever the firmware may have
					done.
		usepirqmask		[IA-32] Honor the possible IRQ mask
					stored in the BIOS $PIR table. This is
					needed on some systems with broken
					BIOSes, notably some HP Pavilion N5400
					and Omnibook XE3 notebooks. This will
					have no effect if ACPI IRQ routing is
					enabled.
		noacpi			[IA-32] Do not use ACPI for IRQ routing.

	pcmv=		[HW,PCMCIA] BadgePAD 4

	pd.		[PARIDE]
			See Documentation/paride.txt.

	pf.		[PARIDE]
			See Documentation/paride.txt.

	pg.		[PARIDE]
			See Documentation/paride.txt.

	pirq=		[SMP,APIC] Manual mp-table setup
			See Documentation/i386/IO-APIC.txt.

	plip=		[PPT,NET] Parallel port network link
			Format: { parport<nr> | timid | 0 }
			See also Documentation/parport.txt.

	pnpbios=	[ISAPNP]
			{ on | off | curr | res | no-curr | no-res }

	pnp_reserve_irq=
			[ISAPNP] Exclude IRQs for the autoconfiguration

	pnp_reserve_dma=
			[ISAPNP] Exclude DMAs for the autoconfiguration

	pnp_reserve_io=	[ISAPNP] Exclude I/O ports for the autoconfiguration
		     	Ranges are in pairs (I/O port base and size).

	pnp_reserve_mem=
			[ISAPNP] Exclude memory regions for the autoconfiguration
			Ranges are in pairs (memory base and size).

	profile=	[KNL] Enable kernel profiling via /proc/profile
			(param: profile step/bucket size as a power of 2)

	prompt_ramdisk=	[RAM] List of RAM disks to prompt for floppy disk
			before loading.
			See Documentation/ramdisk.txt.

	psmouse.proto=  [HW,MOUSE] Highest PS2 mouse protocol extension to
			probe for (bare|imps|exps).
	psmouse.rate=	[HW,MOUSE] Set desired mouse report rate, in reports
			per second.
	psmouse.resetafter=
			[HW,MOUSE] Try to reset Synaptics Touchpad after so many
			bad packets (0 = never).
	psmouse.resolution=
			[HW,MOUSE] Set desired mouse resolution, in dpi.
	psmouse.smartscroll=
			[HW,MOUSE] Controls Logitech smartscroll autorepeat,
			0 = disabled, 1 = enabled (default).

	pss=		[HW,OSS] Personal Sound System (ECHO ESC614)
			Format: <io>,<mss_io>,<mss_irq>,<mss_dma>,<mpu_io>,<mpu_irq>

	pt.		[PARIDE]
			See Documentation/paride.txt.

	quiet=		[KNL] Disable log messages
 
	r128=		[HW,DRM]

	raid=		[HW,RAID]
			See Documentation/md.txt.

	ramdisk=	[RAM] Sizes of RAM disks in kilobytes [deprecated]
			See Documentation/ramdisk.txt.

	ramdisk_blocksize=
			[RAM]
			See Documentation/ramdisk.txt.
 
	ramdisk_size=	[RAM] Sizes of RAM disks in kilobytes
			New name for the ramdisk parameter.
			See Documentation/ramdisk.txt.

	ramdisk_start=	[RAM] Starting block of RAM disk image (so you can
			place it after the kernel image on a boot floppy).
			See Documentation/ramdisk.txt.

	reboot=		[BUGS=IA-32,BUGS=ARM,BUGS=IA-64] Rebooting mode
			Format: <reboot_mode>[,<reboot_mode2>[,...]]
			See arch/*/kernel/reboot.c.

	reserve=	[KNL,BUGS] Force the kernel to ignore some iomem area

	resume=		[SWSUSP] Specify the partition device for software suspension

	rhash_entries=	[KNL,NET]
			Set number of hash buckets for route cache

	riscom8=	[HW,SERIAL]
			Format: <io_board1>[,<io_board2>[,...<io_boardN>]]

	ro		[KNL] Mount root device read-only on boot

	root=		[KNL] Root filesystem

	rootflags=	[KNL] Set root filesystem mount option string

	rootfstype=	[KNL] Set root filesystem type

	rw		[KNL] Mount root device read-write on boot

	S		[KNL] Run init in single mode

	sa1100ir	[NET]
			See drivers/net/irda/sa1100_ir.c.

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

	sbni=		[NET] Granch SBNI12 leased line adapter
 
	sbpcd=		[HW,CD] Soundblaster CD adapter
			Format: <io>,<type>
			See a comment before function sbpcd_setup() in
			drivers/cdrom/sbpcd.c.

	sc1200wdt=	[HW,WDT] SC1200 WDT (watchdog) driver
			Format: <io>[,<timeout>[,<isapnp>]]

	scsi_debug_*=	[SCSI]
			See drivers/scsi/scsi_debug.c.

	scsi_default_dev_flags=
			[SCSI] SCSI default device flags
			Format: <integer>

	scsi_dev_flags=	[SCSI] Black/white list entry for vendor and model
			Format: <vendor>:<model>:<flags>
			(flags are integer value)

	scsi_logging=	[SCSI]

	scsihosts=	[SCSI]

	serialnumber	[BUGS=IA-32]

	sf16fm=		[HW] SF16FMI radio driver for Linux
			Format: <io>

	sg_def_reserved_size=
			[SCSI]
 
	sgalaxy=	[HW,OSS]
			Format: <io>,<irq>,<dma>,<dma2>,<sgbase>

	shapers=	[NET]
			Maximal number of shapers.
 
	sim710=		[SCSI,HW]
			See header of drivers/scsi/sim710.c.

	simeth=		[IA-64]
	simscsi=
 
	sjcd=		[HW,CD]
			Format: <io>,<irq>,<dma>
			See header of drivers/cdrom/sjcd.c.

	slram=		[HW,MTD]

	smart2=		[HW]
			Format: <io1>[,<io2>[,...,<io8>]]

	snd-ad1816a=	[HW,ALSA]

	snd-ad1848=	[HW,ALSA]

	snd-ali5451=	[HW,ALSA]

	snd-als100=	[HW,ALSA]

	snd-als4000=	[HW,ALSA]

	snd-azt2320=	[HW,ALSA]

	snd-cmi8330=	[HW,ALSA]

	snd-cmipci=	[HW,ALSA]

	snd-cs4231=	[HW,ALSA]

	snd-cs4232=	[HW,ALSA]

	snd-cs4236=	[HW,ALSA]

	snd-cs4281=	[HW,ALSA]

	snd-cs46xx=	[HW,ALSA]

	snd-dt019x=	[HW,ALSA]

	snd-dummy=	[HW,ALSA]

	snd-emu10k1=	[HW,ALSA]

	snd-ens1370=	[HW,ALSA]

	snd-ens1371=	[HW,ALSA]

	snd-es968=	[HW,ALSA]

	snd-es1688=	[HW,ALSA]

	snd-es18xx=	[HW,ALSA]

	snd-es1938=	[HW,ALSA]

	snd-es1968=	[HW,ALSA]

	snd-fm801=	[HW,ALSA]

	snd-gusclassic=	[HW,ALSA]

	snd-gusextreme=	[HW,ALSA]

	snd-gusmax=	[HW,ALSA]

	snd-hdsp=	[HW,ALSA]

	snd-ice1712=	[HW,ALSA]

	snd-intel8x0=	[HW,ALSA]

	snd-interwave=	[HW,ALSA]

	snd-interwave-stb=
			[HW,ALSA]

	snd-korg1212=	[HW,ALSA]

	snd-maestro3=	[HW,ALSA]

	snd-mpu401=	[HW,ALSA]

	snd-mtpav=	[HW,ALSA]

	snd-nm256=	[HW,ALSA]

	snd-opl3sa2=	[HW,ALSA]

	snd-opti92x-ad1848=
			[HW,ALSA]

	snd-opti92x-cs4231=
			[HW,ALSA]

	snd-opti93x=	[HW,ALSA]

	snd-pmac=	[HW,ALSA]

	snd-rme32=	[HW,ALSA]

	snd-rme96=	[HW,ALSA]

	snd-rme9652=	[HW,ALSA]

	snd-sb8=	[HW,ALSA]

	snd-sb16=	[HW,ALSA]

	snd-sbawe=	[HW,ALSA]

	snd-serial=	[HW,ALSA]

	snd-sgalaxy=	[HW,ALSA]

	snd-sonicvibes=	[HW,ALSA]

	snd-sun-amd7930=
			[HW,ALSA]

	snd-sun-cs4231=	[HW,ALSA]

	snd-trident=	[HW,ALSA]

	snd-usb-audio=	[HW,ALSA,USB]

	snd-via82xx=	[HW,ALSA]

	snd-virmidi=	[HW,ALSA]

	snd-wavefront=	[HW,ALSA]

	snd-ymfpci=	[HW,ALSA]
 
	sonicvibes=	[HW,OSS]
			Format: <reverb>
 
	sonycd535=	[HW,CD]
			Format: <io>[,<irq>]

	sonypi=		[HW] Sony Programmable I/O Control Device driver
			Format: <minor>,<verbose>,<fnkeyinit>,<camera>,<compat>,<nojogdial>

	specialix=	[HW,SERIAL] Specialix multi-serial port adapter
			See Documentation/specialix.txt.

	speedstep_coppermine=
			[HW,IA-32] Take CPU in your notebook as SpeedStep-capable
			See comment before function speedstep_setup() in
			arch/i386/kernel/cpu/cpufreq/speedstep.c.

	spia_io_base=	[HW,MTD]
	spia_fio_base=
	spia_pedr=
	spia_peddr=

	sscape=		[HW,OSS]
			Format: <io>,<irq>,<dma>,<mpu_io>,<mpu_irq>
 
	st=		[HW,SCSI] SCSI tape parameters (buffers, etc.)
			See Documentation/scsi/st.txt.

	st0x=		[HW,SCSI]
			See header of drivers/scsi/seagate.c.

	sti=		[HW]
			Format: <num>
			Set the STI (builtin display/keyboard on the HP-PARISC
			machines) console (graphic card) which should be used
			as the initial boot-console.
			See also comment in drivers/video/console/sticore.c.

	sti_font=	[HW]
			See comment in drivers/video/console/sticore.c.

	stifb=		[HW]
			Format: bpp:<bpp1>[:<bpp2>[:<bpp3>...]]

	stram_swap=	[HW,M68k]

	swiotlb=	[IA-64] Number of I/O TLB slabs
 
	switches=	[HW,M68k]

	sym53c416=	[HW,SCSI]
			See header of drivers/scsi/sym53c416.c.

	sym53c8xx=	[HW,SCSI]
			See Documentation/scsi/ncr53c8xx.txt.

	t128=		[HW,SCSI]
			See header of drivers/scsi/t128.c.

	tdfx=		[HW,DRM]

	thash_entries=	[KNL,NET]
			Set number of hash buckets for TCP connection

	tipar=		[HW]
			See header of drivers/char/tipar.c.

	tiusb=		[HW,USB] Texas Instruments' USB GraphLink (aka SilverLink)
			Format: <timeout>
 
	tmc8xx=		[HW,SCSI]
			See header of drivers/scsi/seagate.c.

	tmscsim=	[HW,SCSI]
			See comment before function dc390_setup() in
			drivers/scsi/tmscsim.c.

	tp720=		[HW,PS2]

	trix=		[HW,OSS] MediaTrix AudioTrix Pro
			Format: <io>,<irq>,<dma>,<dma2>,<sb_io>,<sb_irq>,<sb_dma>,<mpu_io>,<mpu_irq>
 
	tsdev.xres=	[TS] Horizontal screen resolution.
	tsdev.yres=	[TS] Vertical screen resolution.

	turbografx.map[2|3]=
			[HW,JOY] TurboGraFX parallel port interface
			Format: <port#>,<js1>,<js2>,<js3>,<js4>,<js5>,<js6>,<js7>
			See also Documentation/input/joystick-parport.txt

	u14-34f=	[HW,SCSI] UltraStor 14F/34F SCSI host adapter
			See header of drivers/scsi/u14-34f.c.

	uart401=	[HW,OSS]
			Format: <io>,<irq>

	uart6850=	[HW,OSS]
			Format: <io>,<irq>
 
	video=		[FB] Frame buffer configuration
			See Documentation/fb/modedb.txt.

	vga=		[BOOT,IA-32] Select a particular video mode
			See Documentation/i386/boot.txt and Documentation/svga.txt.
			Use vga=ask for menu.
			This is actually a boot loader parameter; the value is
			passed to the kernel using a special protocol.

	vmhalt=		[KNL,S390]

	vmpoff=		[KNL,S390] 
 
	waveartist=	[HW,OSS]
			Format: <io>,<irq>,<dma>,<dma2>
 
	wd33c93=	[HW,SCSI]
			See header of drivers/scsi/wd33c93.c.

	wd7000=		[HW,SCSI]
			See header of drivers/scsi/wd7000.c.

	wdt=		[WDT] Watchdog
			See Documentation/watchdog/watchdog.txt.

	xd=		[HW,XT] Original XT pre-IDE (RLL encoded) disks.
	xd_geo=		See header of drivers/block/xd.c.

	xirc2ps_cs=	[NET,PCMCIA]
			Format: <irq>,<irq_mask>,<io>,<full_duplex>,<do_sound>,<lockup_hack>[,<irq2>[,<irq3>[,<irq4>]]]



Changelog:

	The last known update (for 2.4.0) - the changelog was not kept before.
	2000-06-??	Mr. Unknown

	Update for 2.5.49, description for most of the options introduced,
	references to other documentation (C files, READMEs, ..), added S390,
	PPC, SPARC, MTD, ALSA and OSS category. Minor corrections and
	reformatting.
	2002-11-24	Petr Baudis <pasky@ucw.cz>
			Randy Dunlap <randy.dunlap@verizon.net>

TODO:

	Add documentation for ALSA options.
	Add more DRM drivers.