clockevents: make device shutdown robust

The device shut down does not cleanup the next_event variable of the
clock event device. So when the device is reactivated the possible
stale next_event value can prevent the device to be reprogrammed as it
claims to wait on a event already.

This is the root cause of the resurfacing suspend/resume problem,
where systems need key press to come back to life.

Fix this by setting next_event to KTIME_MAX when the device is shut
down. Use a separate function for shutdown which takes care of that
and only keep the direct set mode call in the broadcast code, where we
can not touch the next_event value.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

diff --git a/kernel/time/clockevents.c b/kernel/time/clockevents.c
index 1876b526c7783db17d4dd5050a899e640670ef59..f8d968063cea38e348f63590ce73d409385cc5e9 100644 (file)
--- a/kernel/time/clockevents.c
+++ b/kernel/time/clockevents.c
@@ -71,6 +71,16 @@ void clockevents_set_mode(struct clock_event_device *dev,
        }
 }
 
+/**
+ * clockevents_shutdown - shutdown the device and clear next_event
+ * @dev:       device to shutdown
+ */
+void clockevents_shutdown(struct clock_event_device *dev)
+{
+       clockevents_set_mode(dev, CLOCK_EVT_MODE_SHUTDOWN);
+       dev->next_event.tv64 = KTIME_MAX;
+}
+
 /**
  * clockevents_program_event - Reprogram the clock event device.
  * @expires:   absolute expiry time (monotonic clock)
@@ -206,7 +216,7 @@ void clockevents_exchange_device(struct clock_event_device *old,
 
        if (new) {
                BUG_ON(new->mode != CLOCK_EVT_MODE_UNUSED);
-               clockevents_set_mode(new, CLOCK_EVT_MODE_SHUTDOWN);
+               clockevents_shutdown(new);
        }
        local_irq_restore(flags);
 }

diff --git a/kernel/time/tick-broadcast.c b/kernel/time/tick-broadcast.c
index 2f5a38294bf9ffc8639a5e623760c5242e96629b..f1f3eee28113f010492a9e7757d4f5b8ef651714 100644 (file)
--- a/kernel/time/tick-broadcast.c
+++ b/kernel/time/tick-broadcast.c
@@ -236,8 +236,7 @@ static void tick_do_broadcast_on_off(void *why)
                if (!cpu_isset(cpu, tick_broadcast_mask)) {
                        cpu_set(cpu, tick_broadcast_mask);
                        if (td->mode == TICKDEV_MODE_PERIODIC)
-                               clockevents_set_mode(dev,
-                                                    CLOCK_EVT_MODE_SHUTDOWN);
+                               clockevents_shutdown(dev);
                }
                if (*reason == CLOCK_EVT_NOTIFY_BROADCAST_FORCE)
                        tick_broadcast_force = 1;
@@ -254,7 +253,7 @@ static void tick_do_broadcast_on_off(void *why)
 
        if (cpus_empty(tick_broadcast_mask)) {
                if (!bc_stopped)
-                       clockevents_set_mode(bc, CLOCK_EVT_MODE_SHUTDOWN);
+                       clockevents_shutdown(bc);
        } else if (bc_stopped) {
                if (tick_broadcast_device.mode == TICKDEV_MODE_PERIODIC)
                        tick_broadcast_start_periodic(bc);
@@ -306,7 +305,7 @@ void tick_shutdown_broadcast(unsigned int *cpup)
 
        if (tick_broadcast_device.mode == TICKDEV_MODE_PERIODIC) {
                if (bc && cpus_empty(tick_broadcast_mask))
-                       clockevents_set_mode(bc, CLOCK_EVT_MODE_SHUTDOWN);
+                       clockevents_shutdown(bc);
        }
 
        spin_unlock_irqrestore(&tick_broadcast_lock, flags);
@@ -321,7 +320,7 @@ void tick_suspend_broadcast(void)
 
        bc = tick_broadcast_device.evtdev;
        if (bc)
-               clockevents_set_mode(bc, CLOCK_EVT_MODE_SHUTDOWN);
+               clockevents_shutdown(bc);
 
        spin_unlock_irqrestore(&tick_broadcast_lock, flags);
 }

diff --git a/kernel/time/tick-common.c b/kernel/time/tick-common.c
index c4777193d56734d0276aa210ddbbad2e79c416c8..019315ebf9dec4495075b5057cca856e614fa582 100644 (file)
--- a/kernel/time/tick-common.c
+++ b/kernel/time/tick-common.c
@@ -249,7 +249,7 @@ static int tick_check_new_device(struct clock_event_device *newdev)
         * not give it back to the clockevents layer !
         */
        if (tick_is_broadcast_device(curdev)) {
-               clockevents_set_mode(curdev, CLOCK_EVT_MODE_SHUTDOWN);
+               clockevents_shutdown(curdev);
                curdev = NULL;
        }
        clockevents_exchange_device(curdev, newdev);
@@ -311,7 +311,7 @@ static void tick_suspend(void)
        unsigned long flags;
 
        spin_lock_irqsave(&tick_device_lock, flags);
-       clockevents_set_mode(td->evtdev, CLOCK_EVT_MODE_SHUTDOWN);
+       clockevents_shutdown(td->evtdev);
        spin_unlock_irqrestore(&tick_device_lock, flags);
 }
 

diff --git a/kernel/time/tick-internal.h b/kernel/time/tick-internal.h
index 0ffc2918ea6fb8365523ad0a63266cd68628b65f..6e9db9734aa6213d866aaf93c1ec82ecf2ed9b18 100644 (file)
--- a/kernel/time/tick-internal.h
+++ b/kernel/time/tick-internal.h
@@ -10,6 +10,8 @@ extern int tick_do_timer_cpu __read_mostly;
 extern void tick_setup_periodic(struct clock_event_device *dev, int broadcast);
 extern void tick_handle_periodic(struct clock_event_device *dev);
 
+extern void clockevents_shutdown(struct clock_event_device *dev);
+
 /*
  * NO_HZ / high resolution timer shared code
  */