Messages in this thread | | | Date | Fri, 20 Nov 2015 11:29:21 -0800 | Subject | Re: [PATCH v3] alarmtimer: fix unexpected rtc interrupt when system resume from S3 | From | John Stultz <> |
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On Tue, Nov 17, 2015 at 4:08 AM, <zhuo-hao.lee@intel.com> wrote: > 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. > > 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.
So thanks for the extra context here, and again I don't have an objection to this patch.
Although from the earlier discussion it still isn't quite clear to me: Why must the HPET RTC emulation need to fire the alarm every 16ms? Is that not something that can be fixed?
I just want to make sure we're not hiding a deeper issue.
thanks -john
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