From 14d0e347ea2db51144a8800d7c7576db96f69983 Mon Sep 17 00:00:00 2001 From: Zoran Markovic Date: Wed, 26 Jun 2013 16:09:13 -0700 Subject: rtc: Keep system awake until all expired RTC timers are handled Current implementation of RTC interface allows for system suspend to occur in the following cases: (a) if a timer is set in the past and rtc_timer_do_work() is scheduled to handle it, and (b) if rtc_timer_do_work() is called to handle expired timers whose handlers implement a preemption point. A pending suspend request may be honoured in the above cases causing timer handling to be delayed until after the next resume. This is undesirable since timer handlers may have time-critical code to execute. This patch makes sure that the system stays awake until all expired timers are handled. Note that all calls to pm_stay_awake() are eventually paired with the single pm_relax() call in rtc_timer_do_work(), which is launched using schedule_work(). Cc: Alessandro Zummo Cc: John Stultz Cc: Arve Hjonnevag Cc: Todd Poynor Signed-off-by: Zoran Markovic Signed-off-by: John Stultz --- drivers/rtc/interface.c | 13 +++++++++---- 1 file changed, 9 insertions(+), 4 deletions(-) diff --git a/drivers/rtc/interface.c b/drivers/rtc/interface.c index 72c5cdbe0791..544be722937c 100644 --- a/drivers/rtc/interface.c +++ b/drivers/rtc/interface.c @@ -72,6 +72,7 @@ int rtc_set_time(struct rtc_device *rtc, struct rtc_time *tm) } else err = -EINVAL; + pm_stay_awake(rtc->dev.parent); mutex_unlock(&rtc->ops_lock); /* A timer might have just expired */ schedule_work(&rtc->irqwork); @@ -113,6 +114,7 @@ int rtc_set_mmss(struct rtc_device *rtc, unsigned long secs) err = -EINVAL; } + pm_stay_awake(rtc->dev.parent); mutex_unlock(&rtc->ops_lock); /* A timer might have just expired */ schedule_work(&rtc->irqwork); @@ -771,9 +773,10 @@ static int rtc_timer_enqueue(struct rtc_device *rtc, struct rtc_timer *timer) alarm.time = rtc_ktime_to_tm(timer->node.expires); alarm.enabled = 1; err = __rtc_set_alarm(rtc, &alarm); - if (err == -ETIME) + if (err == -ETIME) { + pm_stay_awake(rtc->dev.parent); schedule_work(&rtc->irqwork); - else if (err) { + } else if (err) { timerqueue_del(&rtc->timerqueue, &timer->node); timer->enabled = 0; return err; @@ -818,8 +821,10 @@ static void rtc_timer_remove(struct rtc_device *rtc, struct rtc_timer *timer) alarm.time = rtc_ktime_to_tm(next->expires); alarm.enabled = 1; err = __rtc_set_alarm(rtc, &alarm); - if (err == -ETIME) + if (err == -ETIME) { + pm_stay_awake(rtc->dev.parent); schedule_work(&rtc->irqwork); + } } } @@ -845,7 +850,6 @@ 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))) { @@ -880,6 +884,7 @@ again: } else rtc_alarm_disable(rtc); + pm_relax(rtc->dev.parent); mutex_unlock(&rtc->ops_lock); } -- cgit v1.2.3-70-g09d2 From 397bbf6dee50bb1f07cbdb464c41b0f5b7a85493 Mon Sep 17 00:00:00 2001 From: Prarit Bhargava Date: Fri, 22 Feb 2013 15:08:56 -0500 Subject: clocksource: Fix !CONFIG_CLOCKSOURCE_WATCHDOG compile If I explicitly disable the clocksource watchdog in the x86 Kconfig, the x86 kernel will not compile unless this is properly defined. Cc: John Stultz Cc: Thomas Gleixner Cc: x86@kernel.org Signed-off-by: Prarit Bhargava Signed-off-by: John Stultz --- kernel/time/clocksource.c | 1 + 1 file changed, 1 insertion(+) diff --git a/kernel/time/clocksource.c b/kernel/time/clocksource.c index 50a8736757f3..a2e72b8d28d0 100644 --- a/kernel/time/clocksource.c +++ b/kernel/time/clocksource.c @@ -479,6 +479,7 @@ static inline void clocksource_dequeue_watchdog(struct clocksource *cs) { } static inline void clocksource_resume_watchdog(void) { } static inline int __clocksource_watchdog_kthread(void) { return 0; } static bool clocksource_is_watchdog(struct clocksource *cs) { return false; } +void clocksource_mark_unstable(struct clocksource *cs) { } #endif /* CONFIG_CLOCKSOURCE_WATCHDOG */ -- cgit v1.2.3-70-g09d2 From a97ad0c4b447a132a322cedc3a5f7fa4cab4b304 Mon Sep 17 00:00:00 2001 From: Miroslav Lichvar Date: Thu, 1 Aug 2013 19:31:35 +0200 Subject: ntp: Make periodic RTC update more reliable The current code requires that the scheduled update of the RTC happens in the closest tick to the half of the second. This seems to be difficult to achieve reliably. The scheduled work may be missing the target time by a tick or two and be constantly rescheduled every second. Relax the limit to 10 ticks. As a typical RTC drifts in the 11-minute update interval by several milliseconds, this shouldn't affect the overall accuracy of the RTC much. Signed-off-by: Miroslav Lichvar Signed-off-by: John Stultz --- kernel/time/ntp.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/kernel/time/ntp.c b/kernel/time/ntp.c index 8f5b3b98577b..ab1fa7cb8912 100644 --- a/kernel/time/ntp.c +++ b/kernel/time/ntp.c @@ -475,6 +475,7 @@ static void sync_cmos_clock(struct work_struct *work) * called as close as possible to 500 ms before the new second starts. * This code is run on a timer. If the clock is set, that timer * may not expire at the correct time. Thus, we adjust... + * We want the clock to be within a couple of ticks from the target. */ if (!ntp_synced()) { /* @@ -485,7 +486,7 @@ static void sync_cmos_clock(struct work_struct *work) } getnstimeofday(&now); - if (abs(now.tv_nsec - (NSEC_PER_SEC / 2)) <= tick_nsec / 2) { + if (abs(now.tv_nsec - (NSEC_PER_SEC / 2)) <= tick_nsec * 5) { struct timespec adjust = now; fail = -ENODEV; -- cgit v1.2.3-70-g09d2