From 14d0e347ea2db51144a8800d7c7576db96f69983 Mon Sep 17 00:00:00 2001 From: Zoran Markovic Date: Wed, 26 Jun 2013 16:09:13 -0700 Subject: 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 Cc: John Stultz Cc: Arve Hjonnevag Cc: Todd Poynor Signed-off-by: Zoran Markovic Signed-off-by: John Stultz --- drivers/rtc/interface.c | 13 +++++++++---- 1 file changed, 9 insertions(+), 4 deletions(-) (limited to 'drivers/rtc') 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); } -- cgit v1.2.1