diff options
Diffstat (limited to 'Documentation')
21 files changed, 478 insertions, 381 deletions
diff --git a/Documentation/ABI/testing/sysfs-bus-usb b/Documentation/ABI/testing/sysfs-bus-usb index 7772928..deb6b48 100644 --- a/Documentation/ABI/testing/sysfs-bus-usb +++ b/Documentation/ABI/testing/sysfs-bus-usb @@ -144,3 +144,16 @@ Description: Write a 1 to force the device to disconnect (equivalent to unplugging a wired USB device). + +What: /sys/bus/usb/drivers/.../remove_id +Date: November 2009 +Contact: CHENG Renquan <rqcheng@smu.edu.sg> +Description: + Writing a device ID to this file will remove an ID + that was dynamically added via the new_id sysfs entry. + The format for the device ID is: + idVendor idProduct. After successfully + removing an ID, the driver will no longer support the + device. This is useful to ensure auto probing won't + match the driver to the device. For example: + # echo "046d c315" > /sys/bus/usb/drivers/foo/remove_id diff --git a/Documentation/ABI/testing/sysfs-class-uwb_rc-wusbhc b/Documentation/ABI/testing/sysfs-class-uwb_rc-wusbhc index 4e8106f..25b1e75 100644 --- a/Documentation/ABI/testing/sysfs-class-uwb_rc-wusbhc +++ b/Documentation/ABI/testing/sysfs-class-uwb_rc-wusbhc @@ -23,3 +23,16 @@ Description: Since this relates to security (specifically, the lifetime of PTKs and GTKs) it should not be changed from the default. + +What: /sys/class/uwb_rc/uwbN/wusbhc/wusb_phy_rate +Date: August 2009 +KernelVersion: 2.6.32 +Contact: David Vrabel <david.vrabel@csr.com> +Description: + The maximum PHY rate to use for all connected devices. + This is only of limited use for testing and + development as the hardware's automatic rate + adaptation is better then this simple control. + + Refer to [ECMA-368] section 10.3.1.1 for the value to + use. diff --git a/Documentation/ABI/testing/sysfs-devices-system-cpu b/Documentation/ABI/testing/sysfs-devices-system-cpu index a703b9e..2aae06f 100644 --- a/Documentation/ABI/testing/sysfs-devices-system-cpu +++ b/Documentation/ABI/testing/sysfs-devices-system-cpu @@ -62,6 +62,21 @@ Description: CPU topology files that describe kernel limits related to See Documentation/cputopology.txt for more information. +What: /sys/devices/system/cpu/probe + /sys/devices/system/cpu/release +Date: November 2009 +Contact: Linux kernel mailing list <linux-kernel@vger.kernel.org> +Description: Dynamic addition and removal of CPU's. This is not hotplug + removal, this is meant complete removal/addition of the CPU + from the system. + + probe: writes to this file will dynamically add a CPU to the + system. Information written to the file to add CPU's is + architecture specific. + + release: writes to this file dynamically remove a CPU from + the system. Information writtento the file to remove CPU's + is architecture specific. What: /sys/devices/system/cpu/cpu#/node Date: October 2009 @@ -136,6 +151,24 @@ Description: Discover cpuidle policy and mechanism See files in Documentation/cpuidle/ for more information. +What: /sys/devices/system/cpu/cpu#/cpufreq/* +Date: pre-git history +Contact: cpufreq@vger.kernel.org +Description: Discover and change clock speed of CPUs + + Clock scaling allows you to change the clock speed of the + CPUs on the fly. This is a nice method to save battery + power, because the lower the clock speed, the less power + the CPU consumes. + + There are many knobs to tweak in this directory. + + See files in Documentation/cpu-freq/ for more information. + + In particular, read Documentation/cpu-freq/user-guide.txt + to learn how to control the knobs. + + What: /sys/devices/system/cpu/cpu*/cache/index*/cache_disable_X Date: August 2008 KernelVersion: 2.6.27 diff --git a/Documentation/ABI/testing/sysfs-kernel-slab b/Documentation/ABI/testing/sysfs-kernel-slab index 6dcf75e..8b093f8 100644 --- a/Documentation/ABI/testing/sysfs-kernel-slab +++ b/Documentation/ABI/testing/sysfs-kernel-slab @@ -45,8 +45,9 @@ KernelVersion: 2.6.25 Contact: Pekka Enberg <penberg@cs.helsinki.fi>, Christoph Lameter <cl@linux-foundation.org> Description: - The alloc_fastpath file is read-only and specifies how many - objects have been allocated using the fast path. + The alloc_fastpath file shows how many objects have been + allocated using the fast path. It can be written to clear the + current count. Available when CONFIG_SLUB_STATS is enabled. What: /sys/kernel/slab/cache/alloc_from_partial @@ -55,9 +56,10 @@ KernelVersion: 2.6.25 Contact: Pekka Enberg <penberg@cs.helsinki.fi>, Christoph Lameter <cl@linux-foundation.org> Description: - The alloc_from_partial file is read-only and specifies how - many times a cpu slab has been full and it has been refilled - by using a slab from the list of partially used slabs. + The alloc_from_partial file shows how many times a cpu slab has + been full and it has been refilled by using a slab from the list + of partially used slabs. It can be written to clear the current + count. Available when CONFIG_SLUB_STATS is enabled. What: /sys/kernel/slab/cache/alloc_refill @@ -66,9 +68,9 @@ KernelVersion: 2.6.25 Contact: Pekka Enberg <penberg@cs.helsinki.fi>, Christoph Lameter <cl@linux-foundation.org> Description: - The alloc_refill file is read-only and specifies how many - times the per-cpu freelist was empty but there were objects - available as the result of remote cpu frees. + The alloc_refill file shows how many times the per-cpu freelist + was empty but there were objects available as the result of + remote cpu frees. It can be written to clear the current count. Available when CONFIG_SLUB_STATS is enabled. What: /sys/kernel/slab/cache/alloc_slab @@ -77,8 +79,9 @@ KernelVersion: 2.6.25 Contact: Pekka Enberg <penberg@cs.helsinki.fi>, Christoph Lameter <cl@linux-foundation.org> Description: - The alloc_slab file is read-only and specifies how many times - a new slab had to be allocated from the page allocator. + The alloc_slab file is shows how many times a new slab had to + be allocated from the page allocator. It can be written to + clear the current count. Available when CONFIG_SLUB_STATS is enabled. What: /sys/kernel/slab/cache/alloc_slowpath @@ -87,9 +90,10 @@ KernelVersion: 2.6.25 Contact: Pekka Enberg <penberg@cs.helsinki.fi>, Christoph Lameter <cl@linux-foundation.org> Description: - The alloc_slowpath file is read-only and specifies how many - objects have been allocated using the slow path because of a - refill or allocation from a partial or new slab. + The alloc_slowpath file shows how many objects have been + allocated using the slow path because of a refill or + allocation from a partial or new slab. It can be written to + clear the current count. Available when CONFIG_SLUB_STATS is enabled. What: /sys/kernel/slab/cache/cache_dma @@ -117,10 +121,11 @@ KernelVersion: 2.6.31 Contact: Pekka Enberg <penberg@cs.helsinki.fi>, Christoph Lameter <cl@linux-foundation.org> Description: - The file cpuslab_flush is read-only and specifies how many - times a cache's cpu slabs have been flushed as the result of - destroying or shrinking a cache, a cpu going offline, or as - the result of forcing an allocation from a certain node. + The file cpuslab_flush shows how many times a cache's cpu slabs + have been flushed as the result of destroying or shrinking a + cache, a cpu going offline, or as the result of forcing an + allocation from a certain node. It can be written to clear the + current count. Available when CONFIG_SLUB_STATS is enabled. What: /sys/kernel/slab/cache/ctor @@ -139,8 +144,8 @@ KernelVersion: 2.6.25 Contact: Pekka Enberg <penberg@cs.helsinki.fi>, Christoph Lameter <cl@linux-foundation.org> Description: - The file deactivate_empty is read-only and specifies how many - times an empty cpu slab was deactivated. + The deactivate_empty file shows how many times an empty cpu slab + was deactivated. It can be written to clear the current count. Available when CONFIG_SLUB_STATS is enabled. What: /sys/kernel/slab/cache/deactivate_full @@ -149,8 +154,8 @@ KernelVersion: 2.6.25 Contact: Pekka Enberg <penberg@cs.helsinki.fi>, Christoph Lameter <cl@linux-foundation.org> Description: - The file deactivate_full is read-only and specifies how many - times a full cpu slab was deactivated. + The deactivate_full file shows how many times a full cpu slab + was deactivated. It can be written to clear the current count. Available when CONFIG_SLUB_STATS is enabled. What: /sys/kernel/slab/cache/deactivate_remote_frees @@ -159,9 +164,9 @@ KernelVersion: 2.6.25 Contact: Pekka Enberg <penberg@cs.helsinki.fi>, Christoph Lameter <cl@linux-foundation.org> Description: - The file deactivate_remote_frees is read-only and specifies how - many times a cpu slab has been deactivated and contained free - objects that were freed remotely. + The deactivate_remote_frees file shows how many times a cpu slab + has been deactivated and contained free objects that were freed + remotely. It can be written to clear the current count. Available when CONFIG_SLUB_STATS is enabled. What: /sys/kernel/slab/cache/deactivate_to_head @@ -170,9 +175,9 @@ KernelVersion: 2.6.25 Contact: Pekka Enberg <penberg@cs.helsinki.fi>, Christoph Lameter <cl@linux-foundation.org> Description: - The file deactivate_to_head is read-only and specifies how - many times a partial cpu slab was deactivated and added to the - head of its node's partial list. + The deactivate_to_head file shows how many times a partial cpu + slab was deactivated and added to the head of its node's partial + list. It can be written to clear the current count. Available when CONFIG_SLUB_STATS is enabled. What: /sys/kernel/slab/cache/deactivate_to_tail @@ -181,9 +186,9 @@ KernelVersion: 2.6.25 Contact: Pekka Enberg <penberg@cs.helsinki.fi>, Christoph Lameter <cl@linux-foundation.org> Description: - The file deactivate_to_tail is read-only and specifies how - many times a partial cpu slab was deactivated and added to the - tail of its node's partial list. + The deactivate_to_tail file shows how many times a partial cpu + slab was deactivated and added to the tail of its node's partial + list. It can be written to clear the current count. Available when CONFIG_SLUB_STATS is enabled. What: /sys/kernel/slab/cache/destroy_by_rcu @@ -201,9 +206,9 @@ KernelVersion: 2.6.25 Contact: Pekka Enberg <penberg@cs.helsinki.fi>, Christoph Lameter <cl@linux-foundation.org> Description: - The file free_add_partial is read-only and specifies how many - times an object has been freed in a full slab so that it had to - added to its node's partial list. + The free_add_partial file shows how many times an object has + been freed in a full slab so that it had to added to its node's + partial list. It can be written to clear the current count. Available when CONFIG_SLUB_STATS is enabled. What: /sys/kernel/slab/cache/free_calls @@ -222,9 +227,9 @@ KernelVersion: 2.6.25 Contact: Pekka Enberg <penberg@cs.helsinki.fi>, Christoph Lameter <cl@linux-foundation.org> Description: - The free_fastpath file is read-only and specifies how many - objects have been freed using the fast path because it was an - object from the cpu slab. + The free_fastpath file shows how many objects have been freed + using the fast path because it was an object from the cpu slab. + It can be written to clear the current count. Available when CONFIG_SLUB_STATS is enabled. What: /sys/kernel/slab/cache/free_frozen @@ -233,9 +238,9 @@ KernelVersion: 2.6.25 Contact: Pekka Enberg <penberg@cs.helsinki.fi>, Christoph Lameter <cl@linux-foundation.org> Description: - The free_frozen file is read-only and specifies how many - objects have been freed to a frozen slab (i.e. a remote cpu - slab). + The free_frozen file shows how many objects have been freed to + a frozen slab (i.e. a remote cpu slab). It can be written to + clear the current count. Available when CONFIG_SLUB_STATS is enabled. What: /sys/kernel/slab/cache/free_remove_partial @@ -244,9 +249,10 @@ KernelVersion: 2.6.25 Contact: Pekka Enberg <penberg@cs.helsinki.fi>, Christoph Lameter <cl@linux-foundation.org> Description: - The file free_remove_partial is read-only and specifies how - many times an object has been freed to a now-empty slab so - that it had to be removed from its node's partial list. + The free_remove_partial file shows how many times an object has + been freed to a now-empty slab so that it had to be removed from + its node's partial list. It can be written to clear the current + count. Available when CONFIG_SLUB_STATS is enabled. What: /sys/kernel/slab/cache/free_slab @@ -255,8 +261,9 @@ KernelVersion: 2.6.25 Contact: Pekka Enberg <penberg@cs.helsinki.fi>, Christoph Lameter <cl@linux-foundation.org> Description: - The free_slab file is read-only and specifies how many times an - empty slab has been freed back to the page allocator. + The free_slab file shows how many times an empty slab has been + freed back to the page allocator. It can be written to clear + the current count. Available when CONFIG_SLUB_STATS is enabled. What: /sys/kernel/slab/cache/free_slowpath @@ -265,9 +272,9 @@ KernelVersion: 2.6.25 Contact: Pekka Enberg <penberg@cs.helsinki.fi>, Christoph Lameter <cl@linux-foundation.org> Description: - The free_slowpath file is read-only and specifies how many - objects have been freed using the slow path (i.e. to a full or - partial slab). + The free_slowpath file shows how many objects have been freed + using the slow path (i.e. to a full or partial slab). It can + be written to clear the current count. Available when CONFIG_SLUB_STATS is enabled. What: /sys/kernel/slab/cache/hwcache_align @@ -346,10 +353,10 @@ KernelVersion: 2.6.26 Contact: Pekka Enberg <penberg@cs.helsinki.fi>, Christoph Lameter <cl@linux-foundation.org> Description: - The file order_fallback is read-only and specifies how many - times an allocation of a new slab has not been possible at the - cache's order and instead fallen back to its minimum possible - order. + The order_fallback file shows how many times an allocation of a + new slab has not been possible at the cache's order and instead + fallen back to its minimum possible order. It can be written to + clear the current count. Available when CONFIG_SLUB_STATS is enabled. What: /sys/kernel/slab/cache/partial diff --git a/Documentation/cpu-freq/cpu-drivers.txt b/Documentation/cpu-freq/cpu-drivers.txt index 75a58d1..6c30e930 100644 --- a/Documentation/cpu-freq/cpu-drivers.txt +++ b/Documentation/cpu-freq/cpu-drivers.txt @@ -92,9 +92,9 @@ policy->cpuinfo.max_freq - the minimum and maximum frequency (in kHz) which is supported by this CPU policy->cpuinfo.transition_latency the time it takes on this CPU to - switch between two frequencies (if - appropriate, else specify - CPUFREQ_ETERNAL) + switch between two frequencies in + nanoseconds (if appropriate, else + specify CPUFREQ_ETERNAL) policy->cur The current operating frequency of this CPU (if appropriate) diff --git a/Documentation/cpu-freq/user-guide.txt b/Documentation/cpu-freq/user-guide.txt index 2a5b850..04f6b32 100644 --- a/Documentation/cpu-freq/user-guide.txt +++ b/Documentation/cpu-freq/user-guide.txt @@ -203,6 +203,17 @@ scaling_cur_freq : Current frequency of the CPU as determined by the frequency the kernel thinks the CPU runs at. +bios_limit : If the BIOS tells the OS to limit a CPU to + lower frequencies, the user can read out the + maximum available frequency from this file. + This typically can happen through (often not + intended) BIOS settings, restrictions + triggered through a service processor or other + BIOS/HW based implementations. + This does not cover thermal ACPI limitations + which can be detected through the generic + thermal driver. + If you have selected the "userspace" governor which allows you to set the CPU operating frequency to a specific value, you can read out the current frequency in diff --git a/Documentation/cpu-hotplug.txt b/Documentation/cpu-hotplug.txt index 9d620c1..4d4a644b 100644 --- a/Documentation/cpu-hotplug.txt +++ b/Documentation/cpu-hotplug.txt @@ -49,6 +49,12 @@ maxcpus=n Restrict boot time cpus to n. Say if you have 4 cpus, using additional_cpus=n (*) Use this to limit hotpluggable cpus. This option sets cpu_possible_map = cpu_present_map + additional_cpus +cede_offline={"off","on"} Use this option to disable/enable putting offlined + processors to an extended H_CEDE state on + supported pseries platforms. + If nothing is specified, + cede_offline is set to "on". + (*) Option valid only for following architectures - ia64 diff --git a/Documentation/filesystems/ext3.txt b/Documentation/filesystems/ext3.txt index 05d5cf1..867c5b50 100644 --- a/Documentation/filesystems/ext3.txt +++ b/Documentation/filesystems/ext3.txt @@ -32,8 +32,8 @@ journal_dev=devnum When the external journal device's major/minor numbers identified through its new major/minor numbers encoded in devnum. -noload Don't load the journal on mounting. Note that this forces - mount of inconsistent filesystem, which can lead to +norecovery Don't load the journal on mounting. Note that this forces +noload mount of inconsistent filesystem, which can lead to various problems. data=journal All data are committed into the journal prior to being diff --git a/Documentation/filesystems/nilfs2.txt b/Documentation/filesystems/nilfs2.txt index 01539f4..4949fca 100644 --- a/Documentation/filesystems/nilfs2.txt +++ b/Documentation/filesystems/nilfs2.txt @@ -49,8 +49,7 @@ Mount options NILFS2 supports the following mount options: (*) == default -barrier=on(*) This enables/disables barriers. barrier=off disables - it, barrier=on enables it. +nobarrier Disables barriers. errors=continue(*) Keep going on a filesystem error. errors=remount-ro Remount the filesystem read-only on an error. errors=panic Panic and halt the machine if an error occurs. @@ -71,6 +70,10 @@ order=strict Apply strict in-order semantics that preserves sequence blocks. That means, it is guaranteed that no overtaking of events occurs in the recovered file system after a crash. +norecovery Disable recovery of the filesystem on mount. + This disables every write access on the device for + read-only mounts or snapshots. This option will fail + for r/w mounts on an unclean volume. NILFS2 usage ============ diff --git a/Documentation/filesystems/vfs.txt b/Documentation/filesystems/vfs.txt index 623f094..3de2f32 100644 --- a/Documentation/filesystems/vfs.txt +++ b/Documentation/filesystems/vfs.txt @@ -472,7 +472,7 @@ __sync_single_inode) to check if ->writepages has been successful in writing out the whole address_space. The Writeback tag is used by filemap*wait* and sync_page* functions, -via wait_on_page_writeback_range, to wait for all writeback to +via filemap_fdatawait_range, to wait for all writeback to complete. While waiting ->sync_page (if defined) will be called on each page that is found to require writeback. diff --git a/Documentation/isdn/README.gigaset b/Documentation/isdn/README.gigaset index 0fc9831..794941f 100644 --- a/Documentation/isdn/README.gigaset +++ b/Documentation/isdn/README.gigaset @@ -68,22 +68,38 @@ GigaSet 307x Device Driver for troubleshooting or to pass module parameters. The module ser_gigaset provides a serial line discipline N_GIGASET_M101 - which drives the device through the regular serial line driver. It must - be attached to the serial line to which the M101 is connected with the - ldattach(8) command (requires util-linux-ng release 2.14 or later), for - example: - ldattach GIGASET_M101 /dev/ttyS1 + which uses the regular serial port driver to access the device, and must + therefore be attached to the serial device to which the M101 is connected. + The ldattach(8) command (included in util-linux-ng release 2.14 or later) + can be used for that purpose, for example: + ldattach GIGASET_M101 /dev/ttyS1 This will open the device file, attach the line discipline to it, and then sleep in the background, keeping the device open so that the line discipline remains active. To deactivate it, kill the daemon, for example with - killall ldattach + killall ldattach before disconnecting the device. To have this happen automatically at system startup/shutdown on an LSB compatible system, create and activate an appropriate LSB startup script /etc/init.d/gigaset. (The init name 'gigaset' is officially assigned to this project by LANANA.) Alternatively, just add the 'ldattach' command line to /etc/rc.local. + The modules accept the following parameters: + + Module Parameter Meaning + + gigaset debug debug level (see section 3.2.) + + startmode initial operation mode (see section 2.5.): + bas_gigaset ) 1=ISDN4linux/CAPI (default), 0=Unimodem + ser_gigaset ) + usb_gigaset ) cidmode initial Call-ID mode setting (see section + 2.5.): 1=on (default), 0=off + + Depending on your distribution you may want to create a separate module + configuration file /etc/modprobe.d/gigaset for these, or add them to a + custom file like /etc/modprobe.conf.local. + 2.2. Device nodes for user space programs ------------------------------------ The device can be accessed from user space (eg. by the user space tools @@ -93,11 +109,48 @@ GigaSet 307x Device Driver - /dev/ttyGU0 for M105 (USB data boxes) - /dev/ttyGB0 for the base driver (direct USB connection) - You can also select a "default device" which is used by the frontends when + If you connect more than one device of a type, they will get consecutive + device nodes, eg. /dev/ttyGU1 for a second M105. + + You can also set a "default device" for the user space tools to use when no device node is given as parameter, by creating a symlink /dev/ttyG to one of them, eg.: - ln -s /dev/ttyGB0 /dev/ttyG + ln -s /dev/ttyGB0 /dev/ttyG + + The devices accept the following device specific ioctl calls + (defined in gigaset_dev.h): + + ioctl(int fd, GIGASET_REDIR, int *cmd); + If cmd==1, the device is set to be controlled exclusively through the + character device node; access from the ISDN subsystem is blocked. + If cmd==0, the device is set to be used from the ISDN subsystem and does + not communicate through the character device node. + + ioctl(int fd, GIGASET_CONFIG, int *cmd); + (ser_gigaset and usb_gigaset only) + If cmd==1, the device is set to adapter configuration mode where commands + are interpreted by the M10x DECT adapter itself instead of being + forwarded to the base station. In this mode, the device accepts the + commands described in Siemens document "AT-Kommando Alignment M10x Data" + for setting the operation mode, associating with a base station and + querying parameters like field strengh and signal quality. + Note that there is no ioctl command for leaving adapter configuration + mode and returning to regular operation. In order to leave adapter + configuration mode, write the command ATO to the device. + + ioctl(int fd, GIGASET_BRKCHARS, unsigned char brkchars[6]); + (usb_gigaset only) + Set the break characters on an M105's internal serial adapter to the six + bytes stored in brkchars[]. Unused bytes should be set to zero. + + ioctl(int fd, GIGASET_VERSION, unsigned version[4]); + Retrieve version information from the driver. version[0] must be set to + one of: + - GIGVER_DRIVER: retrieve driver version + - GIGVER_COMPAT: retrieve interface compatibility version + - GIGVER_FWBASE: retrieve the firmware version of the base + Upon return, version[] is filled with the requested version information. 2.3. ISDN4linux ---------- @@ -113,15 +166,24 @@ GigaSet 307x Device Driver Connection State: 0, Response: -1 gigaset_process_response: resp_code -1 in ConState 0 ! Timeout occurred - you might need to use unimodem mode. (see section 2.5.) + you probably need to use unimodem mode. (see section 2.5.) 2.4. CAPI ---- If the driver is compiled with CAPI support (kernel configuration option GIGASET_CAPI, experimental) it can also be used with CAPI 2.0 kernel and - user space applications. ISDN4Linux is supported in this configuration + user space applications. For user space access, the module capi.ko must + be loaded. The capiinit command (included in the capi4k-utils package) + does this for you. + + The CAPI variant of the driver supports legacy ISDN4Linux applications via the capidrv compatibility driver. The kernel module capidrv.ko must - be loaded explicitly ("modprobe capidrv") if needed. + be loaded explicitly with the command + modprobe capidrv + if needed, and cannot be unloaded again without unloading the driver + first. (These are limitations of capidrv.) + + The note about unimodem mode in the preceding section applies here, too. 2.5. Unimodem mode ------------- @@ -134,9 +196,14 @@ GigaSet 307x Device Driver You can switch back using gigacontr --mode isdn - You can also load the driver using e.g. - modprobe usb_gigaset startmode=0 - to prevent the driver from starting in "isdn4linux mode". + You can also put the driver directly into Unimodem mode when it's loaded, + by passing the module parameter startmode=0 to the hardware specific + module, e.g. + modprobe usb_gigaset startmode=0 + or by adding a line like + options usb_gigaset startmode=0 + to an appropriate module configuration file, like /etc/modprobe.d/gigaset + or /etc/modprobe.conf.local. In this mode the device works like a modem connected to a serial port (the /dev/ttyGU0, ... mentioned above) which understands the commands @@ -164,9 +231,8 @@ GigaSet 307x Device Driver options ppp_async flag_time=0 - to /etc/modprobe.conf. If your distribution has some local module - configuration file like /etc/modprobe.conf.local, - using that should be preferred. + to an appropriate module configuration file, like /etc/modprobe.d/gigaset + or /etc/modprobe.conf.local. 2.6. Call-ID (CID) mode ------------------ @@ -189,12 +255,13 @@ GigaSet 307x Device Driver settings (CID mode). - If you have several DECT data devices (M10x) which you want to use in turn, select Unimodem mode by passing the parameter "cidmode=0" to - the driver ("modprobe usb_gigaset cidmode=0" or modprobe.conf). + the appropriate driver module (ser_gigaset or usb_gigaset). If you want both of these at once, you are out of luck. - You can also use /sys/class/tty/ttyGxy/cidmode for changing the CID mode - setting (ttyGxy is ttyGU0 or ttyGB0). + You can also use the tty class parameter "cidmode" of the device to + change its CID mode while the driver is loaded, eg. + echo 0 > /sys/class/tty/ttyGU0/cidmode 2.7. Unregistered Wireless Devices (M101/M105) ----------------------------------------- @@ -208,7 +275,7 @@ GigaSet 307x Device Driver driver. In that situation, a restricted set of functions is available which includes, in particular, those necessary for registering the device to a base or for switching it between Fixed Part and Portable Part - modes. + modes. See the gigacontr(8) manpage for details. 3. Troubleshooting --------------- @@ -222,9 +289,7 @@ GigaSet 307x Device Driver options isdn dialtimeout=15 - to /etc/modprobe.conf. If your distribution has some local module - configuration file like /etc/modprobe.conf.local, - using that should be preferred. + to /etc/modprobe.d/gigaset, /etc/modprobe.conf.local or a similar file. Problem: Your isdn script aborts with a message about isdnlog. @@ -264,7 +329,8 @@ GigaSet 307x Device Driver The initial value can be set using the debug parameter when loading the module "gigaset", e.g. by adding a line options gigaset debug=0 - to /etc/modprobe.conf, ... + to your module configuration file, eg. /etc/modprobe.d/gigaset or + /etc/modprobe.conf.local. Generated debugging information can be found - as output of the command diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt index 777dc8a..ab95d3a 100644 --- a/Documentation/kernel-parameters.txt +++ b/Documentation/kernel-parameters.txt @@ -1787,6 +1787,11 @@ and is between 256 and 4096 characters. It is defined in the file waiting for the ACK, so if this is set too high interrupts *may* be lost! + omap_mux= [OMAP] Override bootloader pin multiplexing. + Format: <mux_mode0.mode_name=value>... + For example, to override I2C bus2: + omap_mux=i2c2_scl.i2c2_scl=0x100,i2c2_sda.i2c2_sda=0x100 + opl3= [HW,OSS] Format: <io> @@ -2663,6 +2668,8 @@ and is between 256 and 4096 characters. It is defined in the file to a common usb-storage quirk flag as follows: a = SANE_SENSE (collect more than 18 bytes of sense data); + b = BAD_SENSE (don't collect more than 18 + bytes of sense data); c = FIX_CAPACITY (decrease the reported device capacity by one sector); h = CAPACITY_HEURISTICS (decrease the diff --git a/Documentation/lockstat.txt b/Documentation/lockstat.txt index 9cb9138..65f4c79 100644 --- a/Documentation/lockstat.txt +++ b/Documentation/lockstat.txt @@ -62,8 +62,20 @@ applicable). It also tracks 4 contention points per class. A contention point is a call site that had to wait on lock acquisition. + - CONFIGURATION + +Lock statistics are enabled via CONFIG_LOCK_STATS. + - USAGE +Enable collection of statistics: + +# echo 1 >/proc/sys/kernel/lock_stat + +Disable collection of statistics: + +# echo 0 >/proc/sys/kernel/lock_stat + Look at the current lock statistics: ( line numbers not part of actual output, done for clarity in the explanation diff --git a/Documentation/md.txt b/Documentation/md.txt index 4edd39e..188f476 100644 --- a/Documentation/md.txt +++ b/Documentation/md.txt @@ -233,9 +233,9 @@ All md devices contain: resync_start The point at which resync should start. If no resync is needed, - this will be a very large number. At array creation it will - default to 0, though starting the array as 'clean' will - set it much larger. + this will be a very large number (or 'none' since 2.6.30-rc1). At + array creation it will default to 0, though starting the array as + 'clean' will set it much larger. new_dev This file can be written but not read. The value written should @@ -296,6 +296,51 @@ All md devices contain: active-idle like active, but no writes have been seen for a while (safe_mode_delay). + bitmap/location + This indicates where the write-intent bitmap for the array is + stored. + It can be one of "none", "file" or "[+-]N". + "file" may later be extended to "file:/file/name" + "[+-]N" means that many sectors from the start of the metadata. + This is replicated on all devices. For arrays with externally + managed metadata, the offset is from the beginning of the + device. + bitmap/chunksize + The size, in bytes, of the chunk which will be represented by a + single bit. For RAID456, it is a portion of an individual + device. For RAID10, it is a portion of the array. For RAID1, it + is both (they come to the same thing). + bitmap/time_base + The time, in seconds, between looking for bits in the bitmap to + be cleared. In the current implementation, a bit will be cleared + between 2 and 3 times "time_base" after all the covered blocks + are known to be in-sync. + bitmap/backlog + When write-mostly devices are active in a RAID1, write requests + to those devices proceed in the background - the filesystem (or + other user of the device) does not have to wait for them. + 'backlog' sets a limit on the number of concurrent background + writes. If there are more than this, new writes will by + synchronous. + bitmap/metadata + This can be either 'internal' or 'external'. + 'internal' is the default and means the metadata for the bitmap + is stored in the first 256 bytes of the allocated space and is + managed by the md module. + 'external' means that bitmap metadata is managed externally to + the kernel (i.e. by some userspace program) + bitmap/can_clear + This is either 'true' or 'false'. If 'true', then bits in the + bitmap will be cleared when the corresponding blocks are thought + to be in-sync. If 'false', bits will never be cleared. + This is automatically set to 'false' if a write happens on a + degraded array, or if the array becomes degraded during a write. + When metadata is managed externally, it should be set to true + once the array becomes non-degraded, and this fact has been + recorded in the metadata. + + + As component devices are added to an md array, they appear in the 'md' directory as new directories named @@ -334,8 +379,9 @@ Each directory contains: Writing "writemostly" sets the writemostly flag. Writing "-writemostly" clears the writemostly flag. Writing "blocked" sets the "blocked" flag. - Writing "-blocked" clear the "blocked" flag and allows writes + Writing "-blocked" clears the "blocked" flag and allows writes to complete. + Writing "in_sync" sets the in_sync flag. This file responds to select/poll. Any change to 'faulty' or 'blocked' causes an event. @@ -372,6 +418,24 @@ Each directory contains: array. If a value less than the current component_size is written, it will be rejected. + recovery_start + + When the device is not 'in_sync', this records the number of + sectors from the start of the device which are known to be + correct. This is normally zero, but during a recovery + operation is will steadily increase, and if the recovery is + interrupted, restoring this value can cause recovery to + avoid repeating the earlier blocks. With v1.x metadata, this + value is saved and restored automatically. + + This can be set whenever the device is not an active member of + the array, either before the array is activated, or before + the 'slot' is set. + + Setting this to 'none' is equivalent to setting 'in_sync'. + Setting to any other value also clears the 'in_sync' flag. + + An active md device will also contain and entry for each active device in the array. These are named diff --git a/Documentation/powerpc/dts-bindings/fsl/board.txt b/Documentation/powerpc/dts-bindings/fsl/board.txt index e8b5bc2..39e9415 100644 --- a/Documentation/powerpc/dts-bindings/fsl/board.txt +++ b/Documentation/powerpc/dts-bindings/fsl/board.txt @@ -20,12 +20,16 @@ Required properities: - compatible : should be "fsl,fpga-pixis". - reg : should contain the address and the length of the FPPGA register set. +- interrupt-parent: should specify phandle for the interrupt controller. +- interrupts : should specify event (wakeup) IRQ. Example (MPC8610HPCD): board-control@e8000000 { compatible = "fsl,fpga-pixis"; reg = <0xe8000000 32>; + interrupt-parent = <&mpic>; + interrupts = <8 8>; }; * Freescale BCSR GPIO banks diff --git a/Documentation/powerpc/dts-bindings/fsl/mpc5200.txt b/Documentation/powerpc/dts-bindings/fsl/mpc5200.txt index cabc780..5c6602d 100644 --- a/Documentation/powerpc/dts-bindings/fsl/mpc5200.txt +++ b/Documentation/powerpc/dts-bindings/fsl/mpc5200.txt @@ -103,7 +103,22 @@ fsl,mpc5200-gpt nodes --------------------- On the mpc5200 and 5200b, GPT0 has a watchdog timer function. If the board design supports the internal wdt, then the device node for GPT0 should -include the empty property 'fsl,has-wdt'. +include the empty property 'fsl,has-wdt'. Note that this does not activate +the watchdog. The timer will function as a GPT if the timer api is used, and +it will function as watchdog if the watchdog device is used. The watchdog +mode has priority over the gpt mode, i.e. if the watchdog is activated, any +gpt api call to this timer will fail with -EBUSY. + +If you add the property + fsl,wdt-on-boot = <n>; +GPT0 will be marked as in-use watchdog, i.e. blocking every gpt access to it. +If n>0, the watchdog is started with a timeout of n seconds. If n=0, the +configuration of the watchdog is not touched. This is useful in two cases: +- just mark GPT0 as watchdog, blocking gpt accesses, and configure it later; +- do not touch a configuration assigned by the boot loader which supervises + the boot process itself. + +The watchdog will respect the CONFIG_WATCHDOG_NOWAYOUT option. An mpc5200-gpt can be used as a single line GPIO controller. To do so, add the following properties to the gpt node: diff --git a/Documentation/powerpc/dts-bindings/xilinx.txt b/Documentation/powerpc/dts-bindings/xilinx.txt index 80339fe..ea68046 100644 --- a/Documentation/powerpc/dts-bindings/xilinx.txt +++ b/Documentation/powerpc/dts-bindings/xilinx.txt @@ -292,4 +292,15 @@ - reg-offset : A value of 3 is required - reg-shift : A value of 2 is required + vii) Xilinx USB Host controller + + The Xilinx USB host controller is EHCI compatible but with a different + base address for the EHCI registers, and it is always a big-endian + USB Host controller. The hardware can be configured as high speed only, + or high speed/full speed hybrid. + + Required properties: + - xlnx,support-usb-fs: A value 0 means the core is built as high speed + only. A value 1 means the core also supports + full speed devices. diff --git a/Documentation/serial/hayes-esp.txt b/Documentation/serial/hayes-esp.txt deleted file mode 100644 index 09b5d58..0000000 --- a/Documentation/serial/hayes-esp.txt +++ /dev/null @@ -1,154 +0,0 @@ -HAYES ESP DRIVER VERSION 2.1 - -A big thanks to the people at Hayes, especially Alan Adamson. Their support -has enabled me to provide enhancements to the driver. - -Please report your experiences with this driver to me (arobinso@nyx.net). I -am looking for both positive and negative feedback. - -*** IMPORTANT CHANGES FOR 2.1 *** -Support for PIO mode. Five situations will cause PIO mode to be used: -1) A multiport card is detected. PIO mode will always be used. (8 port cards -do not support DMA). -2) The DMA channel is set to an invalid value (anything other than 1 or 3). -3) The DMA buffer/channel could not be allocated. The port will revert to PIO -mode until it is reopened. -4) Less than a specified number of bytes need to be transferred to/from the -FIFOs. PIO mode will be used for that transfer only. -5) A port needs to do a DMA transfer and another port is already using the -DMA channel. PIO mode will be used for that transfer only. - -Since the Hayes ESP seems to conflict with other cards (notably sound cards) -when using DMA, DMA is turned off by default. To use DMA, it must be turned -on explicitly, either with the "dma=" option described below or with -setserial. A multiport card can be forced into DMA mode by using setserial; -however, most multiport cards don't support DMA. - -The latest version of setserial allows the enhanced configuration of the ESP -card to be viewed and modified. -*** - -This package contains the files needed to compile a module to support the Hayes -ESP card. The drivers are basically a modified version of the serial drivers. - -Features: - -- Uses the enhanced mode of the ESP card, allowing a wider range of - interrupts and features than compatibility mode -- Uses DMA and 16 bit PIO mode to transfer data to and from the ESP's FIFOs, - reducing CPU load -- Supports primary and secondary ports - - -If the driver is compiled as a module, the IRQs to use can be specified by -using the irq= option. The format is: - -irq=[0x100],[0x140],[0x180],[0x200],[0x240],[0x280],[0x300],[0x380] - -The address in brackets is the base address of the card. The IRQ of -nonexistent cards can be set to 0. If an IRQ of a card that does exist is set -to 0, the driver will attempt to guess at the correct IRQ. For example, to set -the IRQ of the card at address 0x300 to 12, the insmod command would be: - -insmod esp irq=0,0,0,0,0,0,12,0 - -The custom divisor can be set by using the divisor= option. The format is the -same as for the irq= option. Each divisor value is a series of hex digits, -with each digit representing the divisor to use for a corresponding port. The -divisor value is constructed RIGHT TO LEFT. Specifying a nonzero divisor value -will automatically set the spd_cust flag. To calculate the divisor to use for -a certain baud rate, divide the port's base baud (generally 921600) by the -desired rate. For example, to set the divisor of the primary port at 0x300 to -4 and the divisor of the secondary port at 0x308 to 8, the insmod command would -be: - -insmod esp divisor=0,0,0,0,0,0,0x84,0 - -The dma= option can be used to set the DMA channel. The channel can be either -1 or 3. Specifying any other value will force the driver to use PIO mode. -For example, to set the DMA channel to 3, the insmod command would be: - -insmod esp dma=3 - -The rx_trigger= and tx_trigger= options can be used to set the FIFO trigger -levels. They specify when the ESP card should send an interrupt. Larger -values will decrease the number of interrupts; however, a value too high may -result in data loss. Valid values are 1 through 1023, with 768 being the -default. For example, to set the receive trigger level to 512 bytes and the -transmit trigger level to 700 bytes, the insmod command would be: - -insmod esp rx_trigger=512 tx_trigger=700 - -The flow_off= and flow_on= options can be used to set the hardware flow off/ -flow on levels. The flow on level must be lower than the flow off level, and -the flow off level should be higher than rx_trigger. Valid values are 1 -through 1023, with 1016 being the default flow off level and 944 being the -default flow on level. For example, to set the flow off level to 1000 bytes -and the flow on level to 935 bytes, the insmod command would be: - -insmod esp flow_off=1000 flow_on=935 - -The rx_timeout= option can be used to set the receive timeout value. This -value indicates how long after receiving the last character that the ESP card -should wait before signalling an interrupt. Valid values are 0 though 255, -with 128 being the default. A value too high will increase latency, and a -value too low will cause unnecessary interrupts. For example, to set the -receive timeout to 255, the insmod command would be: - -insmod esp rx_timeout=255 - -The pio_threshold= option sets the threshold (in number of characters) for -using PIO mode instead of DMA mode. For example, if this value is 32, -transfers of 32 bytes or less will always use PIO mode. - -insmod esp pio_threshold=32 - -Multiple options can be listed on the insmod command line by separating each -option with a space. For example: - -insmod esp dma=3 trigger=512 - -The esp module can be automatically loaded when needed. To cause this to -happen, add the following lines to /etc/modprobe.conf (replacing the last line -with options for your configuration): - -alias char-major-57 esp -alias char-major-58 esp -options esp irq=0,0,0,0,0,0,3,0 divisor=0,0,0,0,0,0,0x4,0 - -You may also need to run 'depmod -a'. - -Devices must be created manually. To create the devices, note the output from -the module after it is inserted. The output will appear in the location where -kernel messages usually appear (usually /var/adm/messages). Create two devices -for each 'tty' mentioned, one with major of 57 and the other with major of 58. -The minor number should be the same as the tty number reported. The commands -would be (replace ? with the tty number): - -mknod /dev/ttyP? c 57 ? -mknod /dev/cup? c 58 ? - -For example, if the following line appears: - -Oct 24 18:17:23 techno kernel: ttyP8 at 0x0140 (irq = 3) is an ESP primary port - -...two devices should be created: - -mknod /dev/ttyP8 c 57 8 -mknod /dev/cup8 c 58 8 - -You may need to set the permissions on the devices: - -chmod 666 /dev/ttyP* -chmod 666 /dev/cup* - -The ESP module and the serial module should not conflict (they can be used at -the same time). After the ESP module has been loaded the ports on the ESP card -will no longer be accessible by the serial driver. - -If I/O errors are experienced when accessing the port, check for IRQ and DMA -conflicts ('cat /proc/interrupts' and 'cat /proc/dma' for a list of IRQs and -DMAs currently in use). - -Enjoy! -Andrew J. Robinson <arobinso@nyx.net> diff --git a/Documentation/serial/tty.txt b/Documentation/serial/tty.txt index 8e65c44..5e5349a 100644 --- a/Documentation/serial/tty.txt +++ b/Documentation/serial/tty.txt @@ -42,7 +42,8 @@ TTY side interfaces: open() - Called when the line discipline is attached to the terminal. No other call into the line discipline for this tty will occur until it - completes successfully. Can sleep. + completes successfully. Returning an error will + prevent the ldisc from being attached. Can sleep. close() - This is called on a terminal when the line discipline is being unplugged. At the point of @@ -52,7 +53,7 @@ close() - This is called on a terminal when the line hangup() - Called when the tty line is hung up. The line discipline should cease I/O to the tty. No further calls into the ldisc code will occur. - Can sleep. + The return value is ignored. Can sleep. write() - A process is writing data through the line discipline. Multiple write calls are serialized @@ -83,6 +84,10 @@ ioctl() - Called when an ioctl is handed to the tty layer that might be for the ldisc. Multiple ioctl calls may occur in parallel. May sleep. +compat_ioctl() - Called when a 32 bit ioctl is handed to the tty layer + that might be for the ldisc. Multiple ioctl calls + may occur in parallel. May sleep. + Driver Side Interfaces: receive_buf() - Hand buffers of bytes from the driver to the ldisc diff --git a/Documentation/spinlocks.txt b/Documentation/spinlocks.txt index 619699d..178c831 100644 --- a/Documentation/spinlocks.txt +++ b/Documentation/spinlocks.txt @@ -1,73 +1,8 @@ -SPIN_LOCK_UNLOCKED and RW_LOCK_UNLOCKED defeat lockdep state tracking and -are hence deprecated. +Lesson 1: Spin locks -Please use DEFINE_SPINLOCK()/DEFINE_RWLOCK() or -__SPIN_LOCK_UNLOCKED()/__RW_LOCK_UNLOCKED() as appropriate for static -initialization. - -Most of the time, you can simply turn: - - static spinlock_t xxx_lock = SPIN_LOCK_UNLOCKED; - -into: - - static DEFINE_SPINLOCK(xxx_lock); - -Static structure member variables go from: - - struct foo bar { - .lock = SPIN_LOCK_UNLOCKED; - }; - -to: - - struct foo bar { - .lock = __SPIN_LOCK_UNLOCKED(bar.lock); - }; - -Declaration of static rw_locks undergo a similar transformation. - -Dynamic initialization, when necessary, may be performed as -demonstrated below. - - spinlock_t xxx_lock; - rwlock_t xxx_rw_lock; - - static int __init xxx_init(void) - { - spin_lock_init(&xxx_lock); - rwlock_init(&xxx_rw_lock); - ... - } - - module_init(xxx_init); - -The following discussion is still valid, however, with the dynamic -initialization of spinlocks or with DEFINE_SPINLOCK, etc., used -instead of SPIN_LOCK_UNLOCKED. - ------------------------ - -On Fri, 2 Jan 1998, Doug Ledford wrote: -> -> I'm working on making the aic7xxx driver more SMP friendly (as well as -> importing the latest FreeBSD sequencer code to have 7895 support) and wanted -> to get some info from you. The goal here is to make the various routines -> SMP safe as well as UP safe during interrupts and other manipulating -> routines. So far, I've added a spin_lock variable to things like my queue -> structs. Now, from what I recall, there are some spin lock functions I can -> use to lock these spin locks from other use as opposed to a (nasty) -> save_flags(); cli(); stuff; restore_flags(); construct. Where do I find -> these routines and go about making use of them? Do they only lock on a -> per-processor basis or can they also lock say an interrupt routine from -> mucking with a queue if the queue routine was manipulating it when the -> interrupt occurred, or should I still use a cli(); based construct on that -> one? - -See <asm/spinlock.h>. The basic version is: - - spinlock_t xxx_lock = SPIN_LOCK_UNLOCKED; +The most basic primitive for locking is spinlock. +static DEFINE_SPINLOCK(xxx_lock); unsigned long flags; @@ -75,13 +10,11 @@ See <asm/spinlock.h>. The basic version is: ... critical section here .. spin_unlock_irqrestore(&xxx_lock, flags); -and the above is always safe. It will disable interrupts _locally_, but the +The above is always safe. It will disable interrupts _locally_, but the spinlock itself will guarantee the global lock, so it will guarantee that there is only one thread-of-control within the region(s) protected by that -lock. - -Note that it works well even under UP - the above sequence under UP -essentially is just the same as doing a +lock. This works well even under UP. The above sequence under UP +essentially is just the same as doing unsigned long flags; @@ -91,15 +24,13 @@ essentially is just the same as doing a so the code does _not_ need to worry about UP vs SMP issues: the spinlocks work correctly under both (and spinlocks are actually more efficient on -architectures that allow doing the "save_flags + cli" in one go because I -don't export that interface normally). +architectures that allow doing the "save_flags + cli" in one operation). + + NOTE! Implications of spin_locks for memory are further described in: -NOTE NOTE NOTE! The reason the spinlock is so much faster than a global -interrupt lock under SMP is exactly because it disables interrupts only on -the local CPU. The spin-lock is safe only when you _also_ use the lock -itself to do locking across CPU's, which implies that EVERYTHING that -touches a shared variable has to agree about the spinlock they want to -use. + Documentation/memory-barriers.txt + (5) LOCK operations. + (6) UNLOCK operations. The above is usually pretty simple (you usually need and want only one spinlock for most things - using more than one spinlock can make things a @@ -120,20 +51,24 @@ and another sequence that does then they are NOT mutually exclusive, and the critical regions can happen at the same time on two different CPU's. That's fine per se, but the critical regions had better be critical for different things (ie they -can't stomp on each other). +can't stomp on each other). The above is a problem mainly if you end up mixing code - for example the routines in ll_rw_block() tend to use cli/sti to protect the atomicity of their actions, and if a driver uses spinlocks instead then you should -think about issues like the above.. +think about issues like the above. This is really the only really hard part about spinlocks: once you start using spinlocks they tend to expand to areas you might not have noticed before, because you have to make sure the spinlocks correctly protect the shared data structures _everywhere_ they are used. The spinlocks are most -easily added to places that are completely independent of other code (ie -internal driver data structures that nobody else ever touches, for -example). +easily added to places that are completely independent of other code (for +example, internal driver data structures that nobody else ever touches). + + NOTE! The spin-lock is safe only when you _also_ use the lock itself + to do locking across CPU's, which implies that EVERYTHING that + touches a shared variable has to agree about the spinlock they want + to use. ---- @@ -141,13 +76,17 @@ Lesson 2: reader-writer spinlocks. If your data accesses have a very natural pattern where you usually tend to mostly read from the shared variables, the reader-writer locks -(rw_lock) versions of the spinlocks are often nicer. They allow multiple +(rw_lock) versions of the spinlocks are sometimes useful. They allow multiple readers to be in the same critical region at once, but if somebody wants -to change the variables it has to get an exclusive write lock. The -routines look the same as above: +to change the variables it has to get an exclusive write lock. - rwlock_t xxx_lock = RW_LOCK_UNLOCKED; + NOTE! reader-writer locks require more atomic memory operations than + simple spinlocks. Unless the reader critical section is long, you + are better off just using spinlocks. +The routines look the same as above: + + rwlock_t xxx_lock = RW_LOCK_UNLOCKED; unsigned long flags; @@ -159,18 +98,21 @@ routines look the same as above: .. read and write exclusive access to the info ... write_unlock_irqrestore(&xxx_lock, flags); -The above kind of lock is useful for complex data structures like linked -lists etc, especially when you know that most of the work is to just -traverse the list searching for entries without changing the list itself, -for example. Then you can use the read lock for that kind of list -traversal, which allows many concurrent readers. Anything that _changes_ -the list will have to get the write lock. +The above kind of lock may be useful for complex data structures like +linked lists, especially searching for entries without changing the list +itself. The read lock allows many concurrent readers. Anything that +_changes_ the list will have to get the write lock. + + NOTE! RCU is better for list traversal, but requires careful + attention to design detail (see Documentation/RCU/listRCU.txt). -Note: you cannot "upgrade" a read-lock to a write-lock, so if you at _any_ +Also, you cannot "upgrade" a read-lock to a write-lock, so if you at _any_ time need to do any changes (even if you don't do it every time), you have -to get the write-lock at the very beginning. I could fairly easily add a -primitive to create a "upgradeable" read-lock, but it hasn't been an issue -yet. Tell me if you'd want one. +to get the write-lock at the very beginning. + + NOTE! We are working hard to remove reader-writer spinlocks in most + cases, so please don't add a new one without consensus. (Instead, see + Documentation/RCU/rcu.txt for complete information.) ---- @@ -233,4 +175,46 @@ indeed), while write-locks need to protect themselves against interrupts. Linus +---- + +Reference information: + +For dynamic initialization, use spin_lock_init() or rwlock_init() as +appropriate: + + spinlock_t xxx_lock; + rwlock_t xxx_rw_lock; + + static int __init xxx_init(void) + { + spin_lock_init(&xxx_lock); + rwlock_init(&xxx_rw_lock); + ... + } + + module_init(xxx_init); + +For static initialization, use DEFINE_SPINLOCK() / DEFINE_RWLOCK() or +__SPIN_LOCK_UNLOCKED() / __RW_LOCK_UNLOCKED() as appropriate. + +SPIN_LOCK_UNLOCKED and RW_LOCK_UNLOCKED are deprecated. These interfere +with lockdep state tracking. + +Most of the time, you can simply turn: + static spinlock_t xxx_lock = SPIN_LOCK_UNLOCKED; +into: + static DEFINE_SPINLOCK(xxx_lock); + +Static structure member variables go from: + + struct foo bar { + .lock = SPIN_LOCK_UNLOCKED; + }; + +to: + struct foo bar { + .lock = __SPIN_LOCK_UNLOCKED(bar.lock); + }; + +Declaration of static rw_locks undergo a similar transformation. diff --git a/Documentation/usb/power-management.txt b/Documentation/usb/power-management.txt index ad64261..c7c1dc2 100644 --- a/Documentation/usb/power-management.txt +++ b/Documentation/usb/power-management.txt @@ -2,7 +2,7 @@ Alan Stern <stern@rowland.harvard.edu> - October 5, 2007 + November 10, 2009 @@ -123,9 +123,9 @@ relevant attribute files are: wakeup, level, and autosuspend. power/level - This file contains one of three words: "on", "auto", - or "suspend". You can write those words to the file - to change the device's setting. + This file contains one of two words: "on" or "auto". + You can write those words to the file to change the + device's setting. "on" means that the device should be resumed and autosuspend is not allowed. (Of course, system @@ -134,10 +134,10 @@ relevant attribute files are: wakeup, level, and autosuspend. "auto" is the normal state in which the kernel is allowed to autosuspend and autoresume the device. - "suspend" means that the device should remain - suspended, and autoresume is not allowed. (But remote - wakeup may still be allowed, since it is controlled - separately by the power/wakeup attribute.) + (In kernels up to 2.6.32, you could also specify + "suspend", meaning that the device should remain + suspended and autoresume was not allowed. This + setting is no longer supported.) power/autosuspend @@ -313,13 +313,14 @@ three of the methods listed above. In addition, a driver indicates that it supports autosuspend by setting the .supports_autosuspend flag in its usb_driver structure. It is then responsible for informing the USB core whenever one of its interfaces becomes busy or idle. The -driver does so by calling these five functions: +driver does so by calling these six functions: int usb_autopm_get_interface(struct usb_interface *intf); void usb_autopm_put_interface(struct usb_interface *intf); - int usb_autopm_set_interface(struct usb_interface *intf); int usb_autopm_get_interface_async(struct usb_interface *intf); void usb_autopm_put_interface_async(struct usb_interface *intf); + void usb_autopm_get_interface_no_resume(struct usb_interface *intf); + void usb_autopm_put_interface_no_suspend(struct usb_interface *intf); The functions work by maintaining a counter in the usb_interface structure. When intf->pm_usage_count is > 0 then the interface is @@ -331,11 +332,13 @@ considered to be idle, and the kernel may autosuspend the device. associated with the device itself rather than any of its interfaces. This field is used only by the USB core.) -The driver owns intf->pm_usage_count; it can modify the value however -and whenever it likes. A nice aspect of the non-async usb_autopm_* -routines is that the changes they make are protected by the usb_device -structure's PM mutex (udev->pm_mutex); however drivers may change -pm_usage_count without holding the mutex. Drivers using the async +Drivers must not modify intf->pm_usage_count directly; its value +should be changed only be using the functions listed above. Drivers +are responsible for insuring that the overall change to pm_usage_count +during their lifetime balances out to 0 (it may be necessary for the +disconnect method to call usb_autopm_put_interface() one or more times +to fulfill this requirement). The first two routines use the PM mutex +in struct usb_device for mutual exclusion; drivers using the async routines are responsible for their own synchronization and mutual exclusion. @@ -347,11 +350,6 @@ exclusion. attempts an autosuspend if the new value is <= 0 and the device isn't suspended. - usb_autopm_set_interface() leaves pm_usage_count alone. - It attempts an autoresume if the value is > 0 and the device - is suspended, and it attempts an autosuspend if the value is - <= 0 and the device isn't suspended. - usb_autopm_get_interface_async() and usb_autopm_put_interface_async() do almost the same things as their non-async counterparts. The differences are: they do @@ -360,13 +358,11 @@ exclusion. such as an URB's completion handler, but when they return the device will not generally not yet be in the desired state. -There also are a couple of utility routines drivers can use: - - usb_autopm_enable() sets pm_usage_cnt to 0 and then calls - usb_autopm_set_interface(), which will attempt an autosuspend. - - usb_autopm_disable() sets pm_usage_cnt to 1 and then calls - usb_autopm_set_interface(), which will attempt an autoresume. + usb_autopm_get_interface_no_resume() and + usb_autopm_put_interface_no_suspend() merely increment or + decrement the pm_usage_count value; they do not attempt to + carry out an autoresume or an autosuspend. Hence they can be + called in an atomic context. The conventional usage pattern is that a driver calls usb_autopm_get_interface() in its open routine and @@ -400,11 +396,11 @@ though, setting this flag won't cause the kernel to autoresume it. Normally a driver would set this flag in its probe method, at which time the device is guaranteed not to be autosuspended.) -The usb_autopm_* routines have to run in a sleepable process context; -they must not be called from an interrupt handler or while holding a -spinlock. In fact, the entire autosuspend mechanism is not well geared -toward interrupt-driven operation. However there is one thing a -driver can do in an interrupt handler: +The synchronous usb_autopm_* routines have to run in a sleepable +process context; they must not be called from an interrupt handler or +while holding a spinlock. In fact, the entire autosuspend mechanism +is not well geared toward interrupt-driven operation. However there +is one thing a driver can do in an interrupt handler: usb_mark_last_busy(struct usb_device *udev); @@ -423,15 +419,16 @@ an URB had completed too recently. External suspend calls should never be allowed to fail in this way, only autosuspend calls. The driver can tell them apart by checking -udev->auto_pm; this flag will be set to 1 for internal PM events -(autosuspend or autoresume) and 0 for external PM events. +the PM_EVENT_AUTO bit in the message.event argument to the suspend +method; this bit will be set for internal PM events (autosuspend) and +clear for external PM events. Many of the ingredients in the autosuspend framework are oriented towards interfaces: The usb_interface structure contains the pm_usage_cnt field, and the usb_autopm_* routines take an interface pointer as their argument. But somewhat confusingly, a few of the -pieces (usb_mark_last_busy() and udev->auto_pm) use the usb_device -structure instead. Drivers need to keep this straight; they can call +pieces (i.e., usb_mark_last_busy()) use the usb_device structure +instead. Drivers need to keep this straight; they can call interface_to_usbdev() to find the device structure for a given interface. |
