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authorzhuo-hao <zhuo-hao.lee@intel.com>2015-11-17 20:08:07 +0800
committerJohn Stultz <john.stultz@linaro.org>2015-12-03 22:31:42 -0800
commita0e3213f836640065e2a23ad55fa6f72e812a4f1 (patch)
tree4e88e156fa80aebe9bead07c24816911462814de /kernel
parent34db37c63a08b8f06f8ff15c5c301a26635ddf25 (diff)
alarmtimer: Avoid unexpected rtc interrupt when system resume from S3
Before the system go to suspend (S3), if user create a timer with clockid CLOCK_REALTIME_ALARM/CLOCK_BOOTTIME_ALARM and set a "large" timeout value to this timer. The function alarmtimer_suspend will be called to setup a timeout value to RTC timer to avoid the system sleep over time. However, if the system wakeup early than RTC timeout, the RTC timer will not be cleared. And this will cause the hpet_rtc_interrupt come unexpectedly until the RTC timeout. To fix this problem, just adding alarmtimer_resume to cancel the RTC timer. This was noticed because the HPET RTC emulation fires an interrupt every 16ms(=1/2^DEFAULT_RTC_SHIFT) up to the point where the alarm time is reached. This program always hits this situation (https://lkml.org/lkml/2015/11/8/326), if system wake up earlier than alarm time. Cc: Thomas Gleixner <tglx@linutronix.de> Cc: John Stultz <john.stultz@linaro.org> Signed-off-by: Zhuo-hao Lee <zhuo-hao.lee@intel.com> [jstultz: Tweak commit subject & formatting slightly] Signed-off-by: John Stultz <john.stultz@linaro.org>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/time/alarmtimer.c17
1 files changed, 17 insertions, 0 deletions
diff --git a/kernel/time/alarmtimer.c b/kernel/time/alarmtimer.c
index 7fbba635a549..e840ed867a5d 100644
--- a/kernel/time/alarmtimer.c
+++ b/kernel/time/alarmtimer.c
@@ -271,11 +271,27 @@ static int alarmtimer_suspend(struct device *dev)
__pm_wakeup_event(ws, MSEC_PER_SEC);
return ret;
}
+
+static int alarmtimer_resume(struct device *dev)
+{
+ struct rtc_device *rtc;
+
+ rtc = alarmtimer_get_rtcdev();
+ if (rtc)
+ rtc_timer_cancel(rtc, &rtctimer);
+ return 0;
+}
+
#else
static int alarmtimer_suspend(struct device *dev)
{
return 0;
}
+
+static int alarmtimer_resume(struct device *dev)
+{
+ return 0;
+}
#endif
static void alarmtimer_freezerset(ktime_t absexp, enum alarmtimer_type type)
@@ -800,6 +816,7 @@ out:
/* Suspend hook structures */
static const struct dev_pm_ops alarmtimer_pm_ops = {
.suspend = alarmtimer_suspend,
+ .resume = alarmtimer_resume,
};
static struct platform_driver alarmtimer_driver = {