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authorZoran Markovic <zoran.markovic@linaro.org>2013-06-26 16:09:13 -0700
committerJohn Stultz <john.stultz@linaro.org>2013-07-22 09:38:25 -0700
commit14d0e347ea2db51144a8800d7c7576db96f69983 (patch)
treefd56f98424f8f9517ba6be8f8de4fb67147fe828
parent07862c1cd6675cde2dd4bd64e64d704ea2185b79 (diff)
downloadlinux-14d0e347ea2db51144a8800d7c7576db96f69983.tar.bz2
rtc: Keep system awake until all expired RTC timers are handled
Current implementation of RTC interface allows for system suspend to occur in the following cases: (a) if a timer is set in the past and rtc_timer_do_work() is scheduled to handle it, and (b) if rtc_timer_do_work() is called to handle expired timers whose handlers implement a preemption point. A pending suspend request may be honoured in the above cases causing timer handling to be delayed until after the next resume. This is undesirable since timer handlers may have time-critical code to execute. This patch makes sure that the system stays awake until all expired timers are handled. Note that all calls to pm_stay_awake() are eventually paired with the single pm_relax() call in rtc_timer_do_work(), which is launched using schedule_work(). Cc: Alessandro Zummo <a.zummo@towertech.it> Cc: John Stultz <john.stultz@linaro.org> Cc: Arve Hjonnevag <arve@android.com> Cc: Todd Poynor <toddpoynor@google.com> Signed-off-by: Zoran Markovic <zoran.markovic@linaro.org> Signed-off-by: John Stultz <john.stultz@linaro.org>
-rw-r--r--drivers/rtc/interface.c13
1 files changed, 9 insertions, 4 deletions
diff --git a/drivers/rtc/interface.c b/drivers/rtc/interface.c
index 72c5cdbe0791..544be722937c 100644
--- a/drivers/rtc/interface.c
+++ b/drivers/rtc/interface.c
@@ -72,6 +72,7 @@ int rtc_set_time(struct rtc_device *rtc, struct rtc_time *tm)
} else
err = -EINVAL;
+ pm_stay_awake(rtc->dev.parent);
mutex_unlock(&rtc->ops_lock);
/* A timer might have just expired */
schedule_work(&rtc->irqwork);
@@ -113,6 +114,7 @@ int rtc_set_mmss(struct rtc_device *rtc, unsigned long secs)
err = -EINVAL;
}
+ pm_stay_awake(rtc->dev.parent);
mutex_unlock(&rtc->ops_lock);
/* A timer might have just expired */
schedule_work(&rtc->irqwork);
@@ -771,9 +773,10 @@ static int rtc_timer_enqueue(struct rtc_device *rtc, struct rtc_timer *timer)
alarm.time = rtc_ktime_to_tm(timer->node.expires);
alarm.enabled = 1;
err = __rtc_set_alarm(rtc, &alarm);
- if (err == -ETIME)
+ if (err == -ETIME) {
+ pm_stay_awake(rtc->dev.parent);
schedule_work(&rtc->irqwork);
- else if (err) {
+ } else if (err) {
timerqueue_del(&rtc->timerqueue, &timer->node);
timer->enabled = 0;
return err;
@@ -818,8 +821,10 @@ static void rtc_timer_remove(struct rtc_device *rtc, struct rtc_timer *timer)
alarm.time = rtc_ktime_to_tm(next->expires);
alarm.enabled = 1;
err = __rtc_set_alarm(rtc, &alarm);
- if (err == -ETIME)
+ if (err == -ETIME) {
+ pm_stay_awake(rtc->dev.parent);
schedule_work(&rtc->irqwork);
+ }
}
}
@@ -845,7 +850,6 @@ void rtc_timer_do_work(struct work_struct *work)
mutex_lock(&rtc->ops_lock);
again:
- pm_relax(rtc->dev.parent);
__rtc_read_time(rtc, &tm);
now = rtc_tm_to_ktime(tm);
while ((next = timerqueue_getnext(&rtc->timerqueue))) {
@@ -880,6 +884,7 @@ again:
} else
rtc_alarm_disable(rtc);
+ pm_relax(rtc->dev.parent);
mutex_unlock(&rtc->ops_lock);
}