clockevents: fix resume logic

We need to make sure, that the clockevent devices are resumed, before
the tick is resumed. The current resume logic does not guarantee this.

Add CLOCK_EVT_MODE_RESUME and call the set mode functions of the clock
event devices before resuming the tick / oneshot functionality.

Fixup the existing users.

Thanks to Nigel Cunningham for tracking down a long standing thinko,
which affected the jinxed VAIO.

[akpm@linux-foundation.org: xen build fix]
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: john stultz <johnstul@us.ibm.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

2 files changed, 14 insertions, 8 deletions

diff --git a/kernel/time/tick-broadcast.c b/kernel/time/tick-broadcast.c
index 8001d37071..8339af229c 100644
--- a/kernel/time/tick-broadcast.c
+++ b/kernel/time/tick-broadcast.c
@@ -49,7 +49,7 @@ cpumask_t *tick_get_broadcast_mask(void)
  */
 static void tick_broadcast_start_periodic(struct clock_event_device *bc)
 {
-        if (bc && bc->mode == CLOCK_EVT_MODE_SHUTDOWN)
+        if (bc)
                 tick_setup_periodic(bc, 1);
 }
 
@@ -299,7 +299,7 @@ void tick_suspend_broadcast(void)
         spin_lock_irqsave(&tick_broadcast_lock, flags);
 
         bc = tick_broadcast_device.evtdev;
-        if (bc && tick_broadcast_device.mode == TICKDEV_MODE_PERIODIC)
+        if (bc)
                 clockevents_set_mode(bc, CLOCK_EVT_MODE_SHUTDOWN);
 
         spin_unlock_irqrestore(&tick_broadcast_lock, flags);
@@ -316,6 +316,8 @@ int tick_resume_broadcast(void)
         bc = tick_broadcast_device.evtdev;
 
         if (bc) {
+                clockevents_set_mode(bc, CLOCK_EVT_MODE_RESUME);
+
                 switch (tick_broadcast_device.mode) {
                 case TICKDEV_MODE_PERIODIC:
                         if(!cpus_empty(tick_broadcast_mask))
diff --git a/kernel/time/tick-common.c b/kernel/time/tick-common.c
index a96ec9ab34..77a21abc87 100644
--- a/kernel/time/tick-common.c
+++ b/kernel/time/tick-common.c
@@ -318,12 +318,17 @@ static void tick_resume(void)
 {
         struct tick_device *td = &__get_cpu_var(tick_cpu_device);
         unsigned long flags;
+        int broadcast = tick_resume_broadcast();
 
         spin_lock_irqsave(&tick_device_lock, flags);
-        if (td->mode == TICKDEV_MODE_PERIODIC)
-                tick_setup_periodic(td->evtdev, 0);
-        else
-                tick_resume_oneshot();
+        clockevents_set_mode(td->evtdev, CLOCK_EVT_MODE_RESUME);
+
+        if (!broadcast) {
+                if (td->mode == TICKDEV_MODE_PERIODIC)
+                        tick_setup_periodic(td->evtdev, 0);
+                else
+                        tick_resume_oneshot();
+        }
         spin_unlock_irqrestore(&tick_device_lock, flags);
 }
 
@@ -360,8 +365,7 @@ static int tick_notify(struct notifier_block *nb, unsigned long reason,
                 break;
 
         case CLOCK_EVT_NOTIFY_RESUME:
-                if (!tick_resume_broadcast())
-                        tick_resume();
+                tick_resume();
                 break;
 
         default: