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authorRafael J. Wysocki <rjw@sisk.pl>2012-04-29 22:53:42 +0200
committerVarun Wadekar <vwadekar@nvidia.com>2012-07-23 14:08:15 +0530
commita7c9eb116c3c8989131f65874edacc591587290f (patch)
treed8226a1e547c86bac6013bf12678efc9efbf3f08 /Documentation
parente86d6171cfe47cee7ea6a53465bfd221ed3d9dfa (diff)
PM / Sleep: Add user space interface for manipulating wakeup sources, v3
Android allows user space to manipulate wakelocks using two sysfs file located in /sys/power/, wake_lock and wake_unlock. Writing a wakelock name and optionally a timeout to the wake_lock file causes the wakelock whose name was written to be acquired (it is created before is necessary), optionally with the given timeout. Writing the name of a wakelock to wake_unlock causes that wakelock to be released. Implement an analogous interface for user space using wakeup sources. Add the /sys/power/wake_lock and /sys/power/wake_unlock files allowing user space to create, activate and deactivate wakeup sources, such that writing a name and optionally a timeout to wake_lock causes the wakeup source of that name to be activated, optionally with the given timeout. If that wakeup source doesn't exist, it will be created and then activated. Writing a name to wake_unlock causes the wakeup source of that name, if there is one, to be deactivated. Wakeup sources created with the help of wake_lock that haven't been used for more than 5 minutes are garbage collected and destroyed. Moreover, there can be only WL_NUMBER_LIMIT wakeup sources created with the help of wake_lock present at a time. The data type used to track wakeup sources created by user space is called "struct wakelock" to indicate the origins of this feature. This version of the patch includes an rbtree manipulation fix from John Stultz. Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Reviewed-by: NeilBrown <neilb@suse.de>
Diffstat (limited to 'Documentation')
-rw-r--r--Documentation/ABI/testing/sysfs-power42
1 files changed, 42 insertions, 0 deletions
diff --git a/Documentation/ABI/testing/sysfs-power b/Documentation/ABI/testing/sysfs-power
index 237c735db6c9..31725ffeeb3a 100644
--- a/Documentation/ABI/testing/sysfs-power
+++ b/Documentation/ABI/testing/sysfs-power
@@ -189,3 +189,45 @@ Description:
Reading from this file causes the last string successfully
written to it to be returned.
+
+What: /sys/power/wake_lock
+Date: February 2012
+Contact: Rafael J. Wysocki <rjw@sisk.pl>
+Description:
+ The /sys/power/wake_lock file allows user space to create
+ wakeup source objects and activate them on demand (if one of
+ those wakeup sources is active, reads from the
+ /sys/power/wakeup_count file block or return false). When a
+ string without white space is written to /sys/power/wake_lock,
+ it will be assumed to represent a wakeup source name. If there
+ is a wakeup source object with that name, it will be activated
+ (unless active already). Otherwise, a new wakeup source object
+ will be registered, assigned the given name and activated.
+ If a string written to /sys/power/wake_lock contains white
+ space, the part of the string preceding the white space will be
+ regarded as a wakeup source name and handled as descrived above.
+ The other part of the string will be regarded as a timeout (in
+ nanoseconds) such that the wakeup source will be automatically
+ deactivated after it has expired. The timeout, if present, is
+ set regardless of the current state of the wakeup source object
+ in question.
+
+ Reads from this file return a string consisting of the names of
+ wakeup sources created with the help of it that are active at
+ the moment, separated with spaces.
+
+
+What: /sys/power/wake_unlock
+Date: February 2012
+Contact: Rafael J. Wysocki <rjw@sisk.pl>
+Description:
+ The /sys/power/wake_unlock file allows user space to deactivate
+ wakeup sources created with the help of /sys/power/wake_lock.
+ When a string is written to /sys/power/wake_unlock, it will be
+ assumed to represent the name of a wakeup source to deactivate.
+ If a wakeup source object of that name exists and is active at
+ the moment, it will be deactivated.
+
+ Reads from this file return a string consisting of the names of
+ wakeup sources created with the help of /sys/power/wake_lock
+ that are inactive at the moment, separated with spaces.