fedora core 6 1.2949 + vserver 2.2.0
[linux-2.6.git] / Documentation / kernel-parameters.txt
index f710c75..202aad5 100644 (file)
@@ -110,6 +110,13 @@ 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.
 
+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.
+
+
        53c7xx=         [HW,SCSI] Amiga SCSI controllers
                        See header of drivers/scsi/53c7xx.c.
                        See also Documentation/scsi/ncr53c7xx.txt.
@@ -157,6 +164,10 @@ running once the system is up.
        acpi_skip_timer_override [HW,ACPI]
                        Recognize and ignore IRQ0/pin2 Interrupt Override.
                        For broken nForce2 BIOS resulting in XT-PIC timer.
+       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
 
        acpi_dbg_layer= [HW,ACPI]
                        Format: <int>
@@ -282,9 +293,6 @@ running once the system is up.
 
        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 (?)
 
@@ -348,9 +356,9 @@ running once the system is up.
 
        clock=          [BUGS=IA-32, HW] gettimeofday clocksource override.
                        [Deprecated]
-                       Forces specified clocksource (if avaliable) to be used
+                       Forces specified clocksource (if available) to be used
                        when calculating gettimeofday(). If specified
-                       clocksource is not avalible, it defaults to PIT.
+                       clocksource is not available, it defaults to PIT.
                        Format: { pit | tsc | cyclone | pmtmr }
 
        disable_8254_timer
@@ -529,10 +537,6 @@ running once the system is up.
                        Default value is 0.
                        Value can be changed at runtime via /selinux/enforce.
 
-       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.
@@ -544,6 +548,13 @@ running once the system is up.
        eurwdt=         [HW,WDT] Eurotech CPU-1220/1410 onboard watchdog.
                        Format: <io>[,<irq>]
 
+       failslab=
+       fail_page_alloc=
+       fail_make_request=[KNL]
+                       General fault injection mechanism.
+                       Format: <interval>,<probability>,<space>,<times>
+                       See also /Documentation/fault-injection/.
+
        fd_mcs=         [HW,SCSI]
                        See header of drivers/scsi/fd_mcs.c.
 
@@ -553,9 +564,6 @@ running once the system is up.
        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)
@@ -573,11 +581,6 @@ running once the system is up.
        gscd=           [HW,CD]
                        Format: <io>
 
-       gt96100eth=     [NET] MIPS GT96100 Advanced Communication Controller
-
-       gus=            [HW,OSS]
-                       Format: <io>,<irq>,<dma>,<dma16>
-
        gvp11=          [HW,SCSI]
 
        hashdist=       [KNL,NUMA] Large hashes allocated during boot
@@ -603,11 +606,9 @@ running once the system is up.
 
        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
+       i8042.dumbkbd   [HW] Pretend that controller can only read data from
+                            keyboard and cannot control its state
                             (Don't attempt to blink the leds)
        i8042.noaux     [HW] Don't check for auxiliary (== mouse) port
        i8042.nokbd     [HW] Don't check/create keyboard port
@@ -654,6 +655,10 @@ running once the system is up.
        idle=           [HW]
                        Format: idle=poll or idle=halt
 
+       ignore_loglevel [KNL]
+                       Ignore loglevel setting - this will print /all/
+                       kernel messages to the console. Useful for debugging.
+
        ihash_entries=  [KNL]
                        Set number of hash buckets for inode cache.
 
@@ -718,7 +723,12 @@ running once the system is up.
                        Format: <RDP>,<reset>,<pci_scan>,<verbosity>
 
        isolcpus=       [KNL,SMP] Isolate CPUs from the general scheduler.
-                       Format: <cpu number>,...,<cpu number>
+                       Format:
+                       <cpu number>,...,<cpu number>
+                       or
+                       <cpu number>-<cpu number>  (must be a positive range in ascending order)
+                       or a mixture
+                       <cpu number>,...,<cpu number>-<cpu number>
                        This option can be used to specify one or more CPUs
                        to isolate from the general SMP balancing and scheduling
                        algorithms. The only way to move a process onto or off
@@ -836,12 +846,6 @@ running once the system is up.
                        (machvec) in a generic kernel.
                        Example: machvec=hpzx1_swiotlb
 
-       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>
@@ -1022,15 +1026,15 @@ running once the system is up.
                        emulation library even if a 387 maths coprocessor
                        is present.
 
+       noaliencache    [MM, NUMA] Disables the allcoation of alien caches in
+                       the slab allocator.  Saves per-node memory, but will
+                       impact performance on real NUMA hardware.
+
        noalign         [KNL,ARM]
 
        noapic          [SMP,APIC] Tells the kernel to not make use of any
                        IOAPICs that may be present in the system.
 
-       apic            [APIC,i386] Override default heuristics to enable/disable the local
-                       APIC by CONFIG_X86_APIC_AUTO. When this option is set the kernel
-                       will try to use the local APIC.
-
        noasync         [HW,M68K] Disables async and sync negotiation for
                        all devices.
 
@@ -1066,9 +1070,14 @@ running once the system is up.
                        in certain environments such as networked servers or
                        real-time systems.
 
+       noirqbalance    [IA-32,SMP,KNL] Disable kernel irq balancing
+
        noirqdebug      [IA-32] Disables the code which attempts to detect and
                        disable unhandled interrupt sources.
 
+       no_timer_check  [IA-32,X86_64,APIC] Disables the code which tests for
+                       broken timer IRQ sources.
+
        noisapnp        [ISAPNP] Disables ISA PnP code.
 
        noinitrd        [RAM] Tells the kernel not to load any configured
@@ -1113,9 +1122,6 @@ running once the system is up.
        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]
 
@@ -1191,8 +1197,13 @@ running once the system is up.
                                Mechanism 1.
                conf2           [IA-32] Force use of PCI Configuration
                                Mechanism 2.
+               mmconf          [IA-32,X86_64] Enable use of MMCONFIG for PCI
+                               Configuration
                nommconf        [IA-32,X86_64] Disable use of MMCONFIG for PCI
                                Configuration
+               msi             [MSI] If the PCI_MSI kernel config parameter is
+                               enabled, this kernel boot option can be used to
+                               enable the use of MSI interrupts system-wide.
                nomsi           [MSI] If the PCI_MSI kernel config parameter is
                                enabled, this kernel boot option can be used to
                                disable the use of MSI interrupts system-wide.
@@ -1244,6 +1255,15 @@ running once the system is up.
                                bootloader. This is currently used on
                                IXP2000 systems where the bus has to be
                                configured a certain way for adjunct CPUs.
+               noearly         [X86] Don't do any early type 1 scanning.
+                               This might help on some broken boards which
+                               machine check when some devices' config space
+                               is read. But various workarounds are disabled
+                               and some IOMMU drivers will not work.
+               bfsort          Sort PCI devices into breadth-first order.
+                               This sorting is done to get a device
+                               order compatible with older (<= 2.4) kernels.
+               nobfsort        Don't sort PCI devices into breadth-first order.
 
        pcmv=           [HW,PCMCIA] BadgePAD 4
 
@@ -1293,6 +1313,7 @@ running once the system is up.
                        Param: "schedule" - profile schedule points.
                        Param: <number> - step/bucket size as a power of 2 for
                                statistical time based profiling.
+                       Param: "sleep" - profile D-state sleeping (millisecs)
 
        processor.max_cstate=   [HW,ACPI]
                        Limit processor to maximum C-state
@@ -1326,7 +1347,7 @@ running once the system is up.
        pt.             [PARIDE]
                        See Documentation/paride.txt.
 
-       quiet=          [KNL] Disable log messages
+       quiet           [KNL] Disable most log messages
 
        r128=           [HW,DRM]
 
@@ -1352,10 +1373,6 @@ running once the system is up.
        rcu.qlowmark=   [KNL,BOOT] Set threshold of queued
                        RCU callbacks below which batch limiting is re-enabled.
 
-       rcu.rsinterval= [KNL,BOOT,SMP] Set the number of additional
-                       RCU callbacks to queued before forcing reschedule
-                       on all cpus.
-
        rdinit=         [KNL]
                        Format: <full_path>
                        Run specified binary instead of /init from the ramdisk,
@@ -1363,13 +1380,27 @@ running once the system is up.
 
        reboot=         [BUGS=IA-32,BUGS=ARM,BUGS=IA-64] Rebooting mode
                        Format: <reboot_mode>[,<reboot_mode2>[,...]]
-                       See arch/*/kernel/reboot.c.
+                       See arch/*/kernel/reboot.c or arch/*/kernel/process.c                   
 
        reserve=        [KNL,BUGS] Force the kernel to ignore some iomem area
 
+       reservetop=     [IA-32]
+                       Format: nn[KMG]
+                       Reserves a hole at the top of the kernel virtual
+                       address space.
+
+       reset_devices   [KNL] Force drivers to reset the underlying device
+                       during initialization.
+
        resume=         [SWSUSP]
                        Specify the partition device for software suspend
 
+       resume_offset=  [SWSUSP]
+                       Specify the offset from the beginning of the partition
+                       given by "resume=" at which the swap header is located,
+                       in <PAGE_SIZE> units (needed only for swap files).
+                       See  Documentation/power/swsusp-and-swap-files.txt
+
        rhash_entries=  [KNL,NET]
                        Set number of hash buckets for route cache
 
@@ -1420,6 +1451,11 @@ running once the system is up.
 
        scsi_logging=   [SCSI]
 
+       scsi_mod.scan=  [SCSI] sync (default) scans SCSI busses as they are
+                       discovered.  async scans them in kernel threads,
+                       allowing boot to proceed.  none ignores them, expecting
+                       user space to do the scan.
+
        selinux         [SELINUX] Disable or enable SELinux at boot time.
                        Format: { "0" | "1" }
                        See security/selinux/Kconfig help text.
@@ -1442,9 +1478,6 @@ running once the system is up.
 
        sg_def_reserved_size=   [SCSI]
 
-       sgalaxy=        [HW,OSS]
-                       Format: <io>,<irq>,<dma>,<dma2>,<sgbase>
-
        shapers=        [NET]
                        Maximal number of shapers.
 
@@ -1585,9 +1618,6 @@ running once the system is up.
 
        snd-ymfpci=     [HW,ALSA]
 
-       sonicvibes=     [HW,OSS]
-                       Format: <reverb>
-
        sonycd535=      [HW,CD]
                        Format: <io>[,<irq>]
 
@@ -1631,6 +1661,12 @@ running once the system is up.
        sym53c416=      [HW,SCSI]
                        See header of drivers/scsi/sym53c416.c.
 
+       sysrq_always_enabled
+                       [KNL]
+                       Ignore sysrq setting - this boot parameter will
+                       neutralize any effect of /proc/sys/kernel/sysrq.
+                       Useful for debugging.
+
        t128=           [HW,SCSI]
                        See header of drivers/scsi/t128.c.
 
@@ -1683,6 +1719,14 @@ running once the system is up.
        uart6850=       [HW,OSS]
                        Format: <io>,<irq>
 
+       uhci-hcd.ignore_oc=
+                       [USB] Ignore overcurrent events (default N).
+                       Some badly-designed motherboards generate lots of
+                       bogus events, for ports that aren't wired to
+                       anything.  Set this parameter to avoid log spamming.
+                       Note that genuine overcurrent events won't be
+                       reported either.
+
        usbhid.mousepoll=
                        [USBHID] The interval which mice are to be polled at.
 
@@ -1737,6 +1781,9 @@ running once the system is up.
        norandmaps      Don't use address space randomization
                        Equivalent to echo 0 > /proc/sys/kernel/randomize_va_space
 
+       unwind_debug=N  N > 0 will enable dwarf2 unwinder debugging
+                       This is useful to get more information why
+                       you got a "dwarf2 unwinder stuck"
 
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