[PATCH] alarmtimer: fix unexpected rtc interrupt when system resume

[PATCH] alarmtimer: fix unexpected rtc interrupt when system resume

[zhuo-hao.lee]

From: zhuo-hao <zhuo-hao.lee@intel.com>

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.

Signed-off-by: Zhuo-hao Lee <zhuo-hao.lee@intel.com>
---
 kernel/time/alarmtimer.c | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/kernel/time/alarmtimer.c b/kernel/time/alarmtimer.c
index 7fbba63..37ffccd 100644
--- a/kernel/time/alarmtimer.c
+++ b/kernel/time/alarmtimer.c
@@ -271,11 +271,25 @@ 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();
+	return rtc ? rtc_timer_cancel(rtc, &rtctimer) : 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 +814,7 @@ 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 = {
-- 
1.9.1

Re: [PATCH] alarmtimer: fix unexpected rtc interrupt when system resume

[kbuild test robot]

[-- Attachment #1: Type: text/plain, Size: 1275 bytes --]

Hi zhuo-hao,

[auto build test ERROR on: tip/timers/core]
[also build test ERROR on: v4.3 next-20151104]

url:    https://github.com/0day-ci/linux/commits/zhuo-hao-lee-intel-com/alarmtimer-fix-unexpected-rtc-interrupt-when-system-resume/20151105-124811
config: i386-randconfig-x009-11010709 (attached as .config)
reproduce:
        # save the attached .config to linux build tree
        make ARCH=i386 

All error/warnings (new ones prefixed by >>):

   kernel/time/alarmtimer.c: In function 'alarmtimer_resume':
>> kernel/time/alarmtimer.c:280:9: error: void value not ignored as it ought to be
     return rtc ? rtc_timer_cancel(rtc, &rtctimer) : 0;
            ^
>> kernel/time/alarmtimer.c:281:1: warning: control reaches end of non-void function [-Wreturn-type]
    }
    ^

vim +280 kernel/time/alarmtimer.c

   274	
   275	static int alarmtimer_resume(struct device *dev)
   276	{
   277		struct rtc_device *rtc;
   278	
   279		rtc = alarmtimer_get_rtcdev();
 > 280		return rtc ? rtc_timer_cancel(rtc, &rtctimer) : 0;
 > 281	}
   282	
   283	#else
   284	static int alarmtimer_suspend(struct device *dev)

---
0-DAY kernel test infrastructure                Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all                   Intel Corporation

[-- Attachment #2: .config.gz --]
[-- Type: application/octet-stream, Size: 25873 bytes --]

Re: [PATCH] alarmtimer: fix unexpected rtc interrupt when system resume

[kbuild test robot]

Hi zhuo-hao,

[auto build test WARNING on: tip/timers/core]
[also build test WARNING on: v4.3 next-20151104]

url:    https://github.com/0day-ci/linux/commits/zhuo-hao-lee-intel-com/alarmtimer-fix-unexpected-rtc-interrupt-when-system-resume/20151105-124811
reproduce:
        # apt-get install sparse
        make ARCH=x86_64 allmodconfig
        make C=1 CF=-D__CHECK_ENDIAN__


sparse warnings: (new ones prefixed by >>)

>> kernel/time/alarmtimer.c:280:20: sparse: incompatible types in conditional expression (different base types)
   kernel/time/alarmtimer.c: In function 'alarmtimer_resume':
   kernel/time/alarmtimer.c:280:9: error: void value not ignored as it ought to be
     return rtc ? rtc_timer_cancel(rtc, &rtctimer) : 0;
            ^
   kernel/time/alarmtimer.c:281:1: warning: control reaches end of non-void function [-Wreturn-type]
    }
    ^

vim +280 kernel/time/alarmtimer.c

   264		rtc_read_time(rtc, &tm);
   265		now = rtc_tm_to_ktime(tm);
   266		now = ktime_add(now, min);
   267	
   268		/* Set alarm, if in the past reject suspend briefly to handle */
   269		ret = rtc_timer_start(rtc, &rtctimer, now, ktime_set(0, 0));
   270		if (ret < 0)
   271			__pm_wakeup_event(ws, MSEC_PER_SEC);
   272		return ret;
   273	}
   274	
   275	static int alarmtimer_resume(struct device *dev)
   276	{
   277		struct rtc_device *rtc;
   278	
   279		rtc = alarmtimer_get_rtcdev();
 > 280		return rtc ? rtc_timer_cancel(rtc, &rtctimer) : 0;
   281	}
   282	
   283	#else
   284	static int alarmtimer_suspend(struct device *dev)
   285	{
   286		return 0;
   287	}
   288	

---
0-DAY kernel test infrastructure                Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all                   Intel Corporation