clocksource: fix resume logic

We need to make sure that the clocksources are resumed, when timekeeping is
resumed.  The current resume logic does not guarantee this.

Add a resume function pointer to the clocksource struct, so clocksource
drivers which need to reinitialize the clocksource can provide a resume
function.

Add a resume function, which calls the maybe available clocksource resume
functions and resets the watchdog function, so a stable TSC can be used
accross suspend/resume.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: john stultz <johnstul@us.ibm.com>
Cc: Andi Kleen <ak@suse.de>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 2 insertions, 0 deletions

diff --git a/kernel/timer.c b/kernel/timer.c
index de85f8491c1d..59a28b1752f8 100644
--- a/kernel/timer.c
+++ b/kernel/timer.c
@@ -1499,6 +1499,8 @@ unregister_time_interpolator(struct time_interpolator *ti)
                 prev = &curr->next;
         }
 
+        clocksource_resume();
+
         write_seqlock_irqsave(&xtime_lock, flags);
         if (ti == time_interpolator) {
                 /* we lost the best time-interpolator: */