From 7483b4a4d9abf9dcf1ffe6e805ead2847ec3264e Mon Sep 17 00:00:00 2001 From: "Rafael J. Wysocki" Date: Sun, 29 Apr 2012 22:53:22 +0200 Subject: PM / Sleep: Implement opportunistic sleep, v2 Introduce a mechanism by which the kernel can trigger global transitions to a sleep state chosen by user space if there are no active wakeup sources. It consists of a new sysfs attribute, /sys/power/autosleep, that can be written one of the strings returned by reads from /sys/power/state, an ordered workqueue and a work item carrying out the "suspend" operations. If a string representing the system's sleep state is written to /sys/power/autosleep, the work item triggering transitions to that state is queued up and it requeues itself after every execution until user space writes "off" to /sys/power/autosleep. That work item enables the detection of wakeup events using the functions already defined in drivers/base/power/wakeup.c (with one small modification) and calls either pm_suspend(), or hibernate() to put the system into a sleep state. If a wakeup event is reported while the transition is in progress, it will abort the transition and the "system suspend" work item will be queued up again. Signed-off-by: Rafael J. Wysocki Acked-by: Greg Kroah-Hartman Reviewed-by: NeilBrown --- drivers/base/power/wakeup.c | 34 +++++++++++++++++++--------------- 1 file changed, 19 insertions(+), 15 deletions(-) (limited to 'drivers/base') diff --git a/drivers/base/power/wakeup.c b/drivers/base/power/wakeup.c index 1132799421cd..cf1706df7610 100644 --- a/drivers/base/power/wakeup.c +++ b/drivers/base/power/wakeup.c @@ -660,29 +660,33 @@ bool pm_wakeup_pending(void) /** * pm_get_wakeup_count - Read the number of registered wakeup events. * @count: Address to store the value at. + * @block: Whether or not to block. * - * Store the number of registered wakeup events at the address in @count. Block - * if the current number of wakeup events being processed is nonzero. + * Store the number of registered wakeup events at the address in @count. If + * @block is set, block until the current number of wakeup events being + * processed is zero. * - * Return 'false' if the wait for the number of wakeup events being processed to - * drop down to zero has been interrupted by a signal (and the current number - * of wakeup events being processed is still nonzero). Otherwise return 'true'. + * Return 'false' if the current number of wakeup events being processed is + * nonzero. Otherwise return 'true'. */ -bool pm_get_wakeup_count(unsigned int *count) +bool pm_get_wakeup_count(unsigned int *count, bool block) { unsigned int cnt, inpr; - DEFINE_WAIT(wait); - for (;;) { - prepare_to_wait(&wakeup_count_wait_queue, &wait, - TASK_INTERRUPTIBLE); - split_counters(&cnt, &inpr); - if (inpr == 0 || signal_pending(current)) - break; + if (block) { + DEFINE_WAIT(wait); + + for (;;) { + prepare_to_wait(&wakeup_count_wait_queue, &wait, + TASK_INTERRUPTIBLE); + split_counters(&cnt, &inpr); + if (inpr == 0 || signal_pending(current)) + break; - schedule(); + schedule(); + } + finish_wait(&wakeup_count_wait_queue, &wait); } - finish_wait(&wakeup_count_wait_queue, &wait); split_counters(&cnt, &inpr); *count = cnt; -- cgit v1.2.3