[PATCH] Save/restore periodic tick information over suspend/resume

The programming of periodic tick devices needs to be saved/restored
across suspend/resume - otherwise we might end up with a system coming
up that relies on getting a PIT (or HPET) interrupt, while those devices
default to 'no interrupts' after powerup. (To confuse things it worked
to a certain degree on some systems because the lapic gets initialized
as a side-effect of SMP bootup.)

This suspend / resume thing was dropped unintentionally during the
last-minute -mm code reshuffling.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

kernel/timer.c

@@ -997,6 +997,9 @@ static int timekeeping_resume(struct sys_device *dev)
 	write_sequnlock_irqrestore(&xtime_lock, flags);
 
 	touch_softlockup_watchdog();
+
+	clockevents_notify(CLOCK_EVT_NOTIFY_RESUME, NULL);
+
 	/* Resume hrtimers */
 	clock_was_set();
 
@@ -1011,6 +1014,9 @@ static int timekeeping_suspend(struct sys_device *dev, pm_message_t state)
 	timekeeping_suspended = 1;
 	timekeeping_suspend_time = read_persistent_clock();
 	write_sequnlock_irqrestore(&xtime_lock, flags);
+
+	clockevents_notify(CLOCK_EVT_NOTIFY_SUSPEND, NULL);
+
 	return 0;
 }