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clockevents: make device shutdown robust

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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>
This commit is contained in:
Thomas Gleixner 2008-09-16 11:32:50 -07:00
parent f1926ce63b
commit 2344abbcbd
4 changed files with 19 additions and 8 deletions
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12
kernel/time/clockevents.c
View File

@ -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);
}

9
kernel/time/tick-broadcast.c
View File

@ -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);
}

4
kernel/time/tick-common.c
View File

@ -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);
}

2
kernel/time/tick-internal.h
View File

@ -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
*/