[PATCH] USB: only make /sys/class/usb show up when there is something in it

[safe/jmp/linux-2.6] / Documentation / kernel-parameters.txt

diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index fe11fcc..a9d3a17 100644 (file)
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -1,4 +1,4 @@
-February 2003             Kernel Parameters                     v2.5.59
+                          Kernel Parameters

                           ~~~~~~~~~~~~~~~~~
 
 The following is a consolidated list of the kernel parameters as implemented
                           ~~~~~~~~~~~~~~~~~
 
 The following is a consolidated list of the kernel parameters as implemented


@@ -17,9 +17,17 @@ are specified on the kernel command line with the module name plus
 
        usbcore.blinkenlights=1
 
 
        usbcore.blinkenlights=1
 

-The text in square brackets at the beginning of the description states 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:
+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}".
+
+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:

 
        ACPI    ACPI support is enabled.
        ALSA    ALSA sound support is enabled.
 
        ACPI    ACPI support is enabled.
        ALSA    ALSA sound support is enabled.


@@ -49,6 +57,7 @@ restrictions referred to are that the relevant option is valid if:
        MCA     MCA bus support is enabled.
        MDA     MDA console support is enabled.
        MOUSE   Appropriate mouse support is enabled.
        MCA     MCA bus support is enabled.
        MDA     MDA console support is enabled.
        MOUSE   Appropriate mouse support is enabled.

+       MSI     Message Signaled Interrupts (PCI).

        MTD     MTD support is enabled.
        NET     Appropriate network support is enabled.
        NUMA    NUMA support is enabled.
        MTD     MTD support is enabled.
        NET     Appropriate network support is enabled.
        NUMA    NUMA support is enabled.


@@ -335,6 +344,12 @@ running once the system is up.
                        timesource is not avalible, it defaults to PIT.
                        Format: { pit | tsc | cyclone | pmtmr }
 
                        timesource is not avalible, it defaults to PIT.
                        Format: { pit | tsc | cyclone | pmtmr }
 

+       disable_8254_timer
+       enable_8254_timer
+                       [IA32/X86_64] Disable/Enable interrupt 0 timer routing
+                       over the 8254 in addition to over the IO-APIC. The
+                       kernel tries to set a sensible default.
+

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


@@ -360,12 +375,17 @@ running once the system is up.
                tty<n>  Use the virtual console device <n>.
 
                ttyS<n>[,options]
                tty<n>  Use the virtual console device <n>.
 
                ttyS<n>[,options]

+               ttyUSB0[,options]

                        Use the specified serial port.  The options are of
                        Use the specified serial port.  The options are of

-                       the form "bbbbpn", where "bbbb" is the baud rate,
-                       "p" is parity ("n", "o", or "e"), and "n" is bits.
-                       Default is "9600n8".
+                       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 also Documentation/serial-console.txt.
+                       See Documentation/serial-console.txt for more
+                       information.  See
+                       Documentation/networking/netconsole.txt for an
+                       alternative.

 
                uart,io,<addr>[,options]
                uart,mmio,<addr>[,options]
 
                uart,io,<addr>[,options]
                uart,mmio,<addr>[,options]


@@ -452,6 +472,11 @@ running once the system is up.
 
        eata=           [HW,SCSI]
 
 
        eata=           [HW,SCSI]
 

+       ec_intr=        [HW,ACPI] ACPI Embedded Controller interrupt mode
+                       Format: <int>
+                       0: polling mode
+                       non-0: interrupt mode (default)
+

        eda=            [HW,PS2]
 
        edb=            [HW,PS2]
        eda=            [HW,PS2]
 
        edb=            [HW,PS2]


@@ -471,7 +496,7 @@ running once the system is up.
                        arch/i386/kernel/cpu/cpufreq/elanfreq.c.
 
        elevator=       [IOSCHED]
                        arch/i386/kernel/cpu/cpufreq/elanfreq.c.
 
        elevator=       [IOSCHED]

-                       Format: {"as" | "cfq" | "deadline" | "noop"}
+                       Format: {"anticipatory" | "cfq" | "deadline" | "noop"}

                        See Documentation/block/as-iosched.txt and
                        Documentation/block/deadline-iosched.txt for details.
 
                        See Documentation/block/as-iosched.txt and
                        Documentation/block/deadline-iosched.txt for details.
 


@@ -712,9 +737,17 @@ running once the system is up.
        load_ramdisk=   [RAM] List of ramdisks to load from floppy
                        See Documentation/ramdisk.txt.
 
        load_ramdisk=   [RAM] List of ramdisks to load from floppy
                        See Documentation/ramdisk.txt.
 

-       lockd.udpport=  [NFS]
+       lockd.nlm_grace_period=P  [NFS] Assign grace period.
+                       Format: <integer>

 
 

-       lockd.tcpport=  [NFS]
+       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>

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


@@ -989,7 +1022,9 @@ running once the system is up.
                        noexec=on: enable non-executable mappings (default)
                        noexec=off: disable nn-executable mappings
 
                        noexec=on: enable non-executable mappings (default)
                        noexec=off: disable nn-executable mappings
 

-       nofxsr          [BUGS=IA-32]
+       nofxsr          [BUGS=IA-32] Disables x86 floating point extended
+                       register save and restore. The kernel will only save
+                       legacy floating-point registers on task switch.

 
        nohlt           [BUGS=ARM]
 
 
        nohlt           [BUGS=ARM]
 


@@ -1019,6 +1054,8 @@ running once the system is up.
        noltlbs         [PPC] Do not use large page/tlb entries for kernel
                        lowmem mapping on PPC40x.
 
        noltlbs         [PPC] Do not use large page/tlb entries for kernel
                        lowmem mapping on PPC40x.
 

+       nomca           [IA-64] Disable machine check abort handling
+

        nomce           [IA-32] Machine Check Exception
 
        noresidual      [PPC] Don't use residual data on PReP machines.
        nomce           [IA-32] Machine Check Exception
 
        noresidual      [PPC] Don't use residual data on PReP machines.


@@ -1032,6 +1069,8 @@ running once the system is up.
 
        nosbagart       [IA-64]
 
 
        nosbagart       [IA-64]
 

+       nosep           [BUGS=IA-32] Disables x86 SYSENTER/SYSEXIT support.
+

        nosmp           [SMP] Tells an SMP kernel to act as a UP kernel.
 
        nosync          [HW,M68K] Disables sync negotiation for all devices.
        nosmp           [SMP] Tells an SMP kernel to act as a UP kernel.
 
        nosync          [HW,M68K] Disables sync negotiation for all devices.


@@ -1101,6 +1140,11 @@ running once the system is up.
        pas16=          [HW,SCSI]
                        See header of drivers/scsi/pas16.c.
 
        pas16=          [HW,SCSI]
                        See header of drivers/scsi/pas16.c.
 

+       pause_on_oops=
+                       Halt all CPUs after the first oops has been printed for
+                       the specified number of seconds.  This is to be used if
+                       your oopses keep scrolling off the screen.
+

        pcbit=          [HW,ISDN]
 
        pcd.            [PARIDE]
        pcbit=          [HW,ISDN]
 
        pcd.            [PARIDE]


@@ -1120,6 +1164,11 @@ running once the system is up.
                                Mechanism 1.
                conf2           [IA-32] Force use of PCI Configuration
                                Mechanism 2.
                                Mechanism 1.
                conf2           [IA-32] Force use of PCI Configuration
                                Mechanism 2.

+               nommconf        [IA-32,X86_64] Disable use of MMCONFIG for PCI
+                               Configuration
+               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.

                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
                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


@@ -1267,6 +1316,19 @@ running once the system is up.
                        New name for the ramdisk parameter.
                        See Documentation/ramdisk.txt.
 
                        New name for the ramdisk parameter.
                        See Documentation/ramdisk.txt.
 

+       rcu.blimit=     [KNL,BOOT] Set maximum number of finished
+                       RCU callbacks to process in one batch.
+
+       rcu.qhimark=    [KNL,BOOT] Set threshold of queued
+                       RCU callbacks over which batch limiting is disabled.
+
+       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,
        rdinit=         [KNL]
                        Format: <full_path>
                        Run specified binary instead of /init from the ramdisk,


@@ -1340,6 +1402,15 @@ running once the system is up.
                        If enabled at boot time, /selinux/disable can be used
                        later to disable prior to initial policy load.
 
                        If enabled at boot time, /selinux/disable can be used
                        later to disable prior to initial policy load.
 

+       selinux_compat_net =
+                       [SELINUX] Set initial selinux_compat_net flag value.
+                        Format: { "0" | "1" }
+                        0 -- use new secmark-based packet controls
+                        1 -- use legacy packet controls
+                        Default value is 0 (preferred).
+                        Value can be changed at runtime via
+                        /selinux/compat_net.
+

        serialnumber    [BUGS=IA-32]
 
        sg_def_reserved_size=   [SCSI]
        serialnumber    [BUGS=IA-32]
 
        sg_def_reserved_size=   [SCSI]


@@ -1623,22 +1694,11 @@ running once the system is up.
                        Format:
                        <irq>,<irq_mask>,<io>,<full_duplex>,<do_sound>,<lockup_hack>[,<irq2>[,<irq3>[,<irq4>]]]
 
                        Format:
                        <irq>,<irq_mask>,<io>,<full_duplex>,<do_sound>,<lockup_hack>[,<irq2>[,<irq3>[,<irq4>]]]
 

+       norandmaps      Don't use address space randomization
+                       Equivalent to echo 0 > /proc/sys/kernel/randomize_va_space

 
 

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

 
 

-2002-11-24     Petr Baudis <pasky@ucw.cz>
-               Randy Dunlap <randy.dunlap@verizon.net>
-       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.
-
-2005-10-19     Randy Dunlap <rdunlap@xenotime.net>
-       Lots of typos, whitespace, some reformatting.
+______________________________________________________________________

 
 TODO:
 
 
 TODO: