PM: Allow wakeup events to abort freezing of tasks

If there is a wakeup event during the freezing of tasks, suspend or
hibernation will fail anyway.  Since try_to_freeze_tasks() can take
up to 20 seconds to complete or fail, aborting it as soon as a wakeup
event is detected improves the worst case wakeup latency.

Based on a patch from Arve Hjønnevåg.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Pavel Machek <pavel@ucw.cz>

1 files changed, 2 insertions, 0 deletions

diff --git a/include/linux/suspend.h b/include/linux/suspend.h
index 6b1712c51102..26697514c5ec 100644
--- a/include/linux/suspend.h
+++ b/include/linux/suspend.h
@@ -308,6 +308,8 @@ static inline int unregister_pm_notifier(struct notifier_block *nb)
 }
 
 #define pm_notifier(fn, pri)    do { (void)(fn); } while (0)
+
+static inline bool pm_check_wakeup_events(void) { return true; }
 #endif /* !CONFIG_PM_SLEEP */
 
 extern struct mutex pm_mutex;