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authorNeilBrown <neilb@suse.de>2012-08-05 22:56:20 +0200
committerRafael J. Wysocki <rjw@sisk.pl>2012-08-08 20:49:16 +0200
commit7523ceed42d84c1afaa1dc498bffed53c2aa444e (patch)
tree3da6d7ea253851657b49413001c8512871a86f96 /drivers/rtc
parent0d7614f09c1ebdbaa1599a5aba7593f147bf96ee (diff)
RTC: Avoid races between RTC alarm wakeup and suspend.
If an RTC alarm fires just as suspend is happening, it is possible for suspend to complete and the alarm to be missed. To avoid the race, we must register the event with the PM core. As the event is made visible to userspace through a thread which is only scheduled by the interrupt, we need a pm_stay_awake/pm_relax pair preventing suspend from the interrupt until the thread completes its work. This makes the pm_wakeup_event() call in cmos_interrupt unnecessary as it provides suspend protection for all RTCs that use rtc_update_irq. Signed-off-by: NeilBrown <neilb@suse.de> Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Diffstat (limited to 'drivers/rtc')
-rw-r--r--drivers/rtc/interface.c2
-rw-r--r--drivers/rtc/rtc-cmos.c1
2 files changed, 2 insertions, 1 deletions
diff --git a/drivers/rtc/interface.c b/drivers/rtc/interface.c
index eb415bd76494..9592b936b71b 100644
--- a/drivers/rtc/interface.c
+++ b/drivers/rtc/interface.c
@@ -582,6 +582,7 @@ enum hrtimer_restart rtc_pie_update_irq(struct hrtimer *timer)
void rtc_update_irq(struct rtc_device *rtc,
unsigned long num, unsigned long events)
{
+ pm_stay_awake(rtc->dev.parent);
schedule_work(&rtc->irqwork);
}
EXPORT_SYMBOL_GPL(rtc_update_irq);
@@ -844,6 +845,7 @@ 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))) {
diff --git a/drivers/rtc/rtc-cmos.c b/drivers/rtc/rtc-cmos.c
index 132333d75408..4267789ca995 100644
--- a/drivers/rtc/rtc-cmos.c
+++ b/drivers/rtc/rtc-cmos.c
@@ -568,7 +568,6 @@ static irqreturn_t cmos_interrupt(int irq, void *p)
hpet_mask_rtc_irq_bit(RTC_AIE);
CMOS_READ(RTC_INTR_FLAGS);
- pm_wakeup_event(cmos_rtc.dev, 0);
}
spin_unlock(&rtc_lock);