• Rafael J. Wysocki's avatar
    PM / Sleep: Add user space interface for manipulating wakeup sources, v3 · b86ff982
    Rafael J. Wysocki authored
    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: default avatarRafael J. Wysocki <rjw@sisk.pl>
    Acked-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
    Reviewed-by: default avatarNeilBrown <neilb@suse.de>
    b86ff982
wakelock.c 4.29 KB