Re: System automatically wakes up because of Intel Rapid Start Technology

From: Gabriele Mazzotta
Date: Mon Dec 22 2014 - 13:57:34 EST


On Monday 22 December 2014 19:41:52 Gabriele Mazzotta wrote:
> On Monday 22 December 2014 18:02:54 Matthew Garrett wrote:
> > Getting this right is a little bit annoying - if the timer would have
> > expired during the time we were suspended, we don't want to re-enable
> > it. I *think* this covers all cases, and does it in generic code rather
> > than special-casing it. Any chance you can give it a test?
>
> I've done a quick test. has_persistent_clock() is false on my system,
> so this patch has no effect as it is.

I did another quick test and moved the code so that it is executed
before has_persistent_clock() is checked. Everything seems to be
working as intended. I tried to suspend and resume multiple times
within one minute and exactly one minute after the last suspension
the system transitioned from S3 to S4.

I haven't checked properly whether it is OK or not to simply move
the code or not, but I wanted to let you know that it works.

> > diff --git a/drivers/rtc/class.c b/drivers/rtc/class.c
> > index 472a5ad..4e3a2a1 100644
> > --- a/drivers/rtc/class.c
> > +++ b/drivers/rtc/class.c
> > @@ -91,6 +91,8 @@ static int rtc_suspend(struct device *dev)
> > old_system = timespec64_sub(old_system, delta_delta);
> > }
> >
> > + rtc->valid_alarm = !rtc_read_alarm(rtc, &rtc->alarm);
> > +
> > return 0;
> > }
> >
> > @@ -145,6 +147,29 @@ static int rtc_resume(struct device *dev)
> > if (sleep_time.tv_sec >= 0)
> > timekeeping_inject_sleeptime64(&sleep_time);
> > rtc_hctosys_ret = 0;
> > +
> > + /*
> > + * If there was an alarm set before suspend, make sure that the
> > + * platform hasn't overwritten it
> > + */
> > + if (rtc->valid_alarm) {
> > + struct rtc_time tm;
> > + long now, scheduled;
> > +
> > + rtc_read_time(rtc, &tm);
> > + rtc_tm_to_time(&rtc->alarm.time, &scheduled);
> > + rtc_tm_to_time(&tm, &now);
> > +
> > + /* Clear the alarm if it went off during suspend */
> > + if (scheduled <= now) {
> > + rtc_time_to_tm(0, &rtc->alarm.time);
> > + rtc->alarm.enabled = 0;
> > + }
> > +
> > + if (rtc->ops && rtc->ops->set_alarm)
> > + rtc->ops->set_alarm(rtc->dev.parent, &rtc->alarm);
> > + }
> > +
> > return 0;
> > }
> >
> > diff --git a/include/linux/rtc.h b/include/linux/rtc.h
> > index 6d6be09..bc805ff 100644
> > --- a/include/linux/rtc.h
> > +++ b/include/linux/rtc.h
> > @@ -133,6 +133,10 @@ struct rtc_device
> > /* Some hardware can't support UIE mode */
> > int uie_unsupported;
> >
> > +#ifdef CONFIG_PM_SLEEP
> > + struct rtc_wkalrm alarm;
> > + bool valid_alarm;
> > +#endif
> > #ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL
> > struct work_struct uie_task;
> > struct timer_list uie_timer;
> >
> >
> >

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