malhuda/msm-4.14
1
0
Fork 0
mirror of https://github.com/rd-stuffs/msm-4.14.git synced 2025-02-20 11:45:48 +08:00
Code Issues Actions Packages Projects Releases Wiki Activity

drm/nouveau/tmr: handle races with hw when updating the next alarm time

Browse Source 
If the time to the next alarm is short enough, we could race with HW and
end up with an ~4 second delay until it triggers.

Fix this by checking again after we update HW.

Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
Cc: stable@vger.kernel.org
This commit is contained in:
Ben Skeggs 2017-05-11 17:19:48 +10:00
parent 3733bd8b40
commit 1b0f84380b
1 changed files with 16 additions and 10 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

26
drivers/gpu/drm/nouveau/nvkm/subdev/timer/base.c
View File

@ -36,23 +36,29 @@ nvkm_timer_alarm_trigger(struct nvkm_timer *tmr)
unsigned long flags;
LIST_HEAD(exec);
/* move any due alarms off the pending list */
/* Process pending alarms. */
spin_lock_irqsave(&tmr->lock, flags);
list_for_each_entry_safe(alarm, atemp, &tmr->alarms, head) {
if (alarm->timestamp <= nvkm_timer_read(tmr))
list_move_tail(&alarm->head, &exec);
/* Have we hit the earliest alarm that hasn't gone off? */
if (alarm->timestamp > nvkm_timer_read(tmr)) {
/* Schedule it. If we didn't race, we're done. */
tmr->func->alarm_init(tmr, alarm->timestamp);
if (alarm->timestamp > nvkm_timer_read(tmr))
break;
}
/* Move to completed list. We'll drop the lock before
* executing the callback so it can reschedule itself.
*/
list_move_tail(&alarm->head, &exec);
}
/* reschedule interrupt for next alarm time */
if (!list_empty(&tmr->alarms)) {
alarm = list_first_entry(&tmr->alarms, typeof(*alarm), head);
tmr->func->alarm_init(tmr, alarm->timestamp);
} else {
/* Shut down interrupt if no more pending alarms. */
if (list_empty(&tmr->alarms))
tmr->func->alarm_fini(tmr);
}
spin_unlock_irqrestore(&tmr->lock, flags);
/* execute any pending alarm handlers */
/* Execute completed callbacks. */
list_for_each_entry_safe(alarm, atemp, &exec, head) {
list_del_init(&alarm->head);
alarm->func(alarm);