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authorMartin Peres <martin.peres@labri.fr>2014-03-14 00:26:52 +0100
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2014-06-07 10:28:18 -0700
commit92840945e295889bde76fb38531f11dafb34b506 (patch)
tree6543ca0d94bf087d408da00e81680bdac2ba44e7 /drivers/gpu
parent4fe6be724f7045fd6ecf59941b4f94fdd50f82b8 (diff)
drm/nouveau/pm/fan: drop the fan lock in fan_update() before rescheduling
commit 61679fe153b2b9ea5b5e2ab93305419e85e99a9d upstream. This should fix a deadlock that has been reported to us where fan_update() would hold the fan lock and try to grab the alarm_program_lock to reschedule an update. On an other CPU, the alarm_program_lock would have been taken before calling fan_update(), leading to a deadlock. We should Cc: <stable@vger.kernel.org> # 3.9+ Reported-by: Marcin Slusarz <marcin.slusarz@gmail.com> Tested-by: Timothée Ravier <tim@siosm.fr> Tested-by: Boris Fersing (IRC nick fersingb, no public email address) Signed-off-by: Martin Peres <martin.peres@free.fr> Signed-off-by: Ben Skeggs <bskeggs@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/gpu')
-rw-r--r--drivers/gpu/drm/nouveau/core/subdev/therm/fan.c19
1 files changed, 13 insertions, 6 deletions
diff --git a/drivers/gpu/drm/nouveau/core/subdev/therm/fan.c b/drivers/gpu/drm/nouveau/core/subdev/therm/fan.c
index 95f6129eeede..29d4c417a5b3 100644
--- a/drivers/gpu/drm/nouveau/core/subdev/therm/fan.c
+++ b/drivers/gpu/drm/nouveau/core/subdev/therm/fan.c
@@ -54,8 +54,10 @@ nouveau_fan_update(struct nouveau_fan *fan, bool immediate, int target)
/* check that we're not already at the target duty cycle */
duty = fan->get(therm);
- if (duty == target)
- goto done;
+ if (duty == target) {
+ spin_unlock_irqrestore(&fan->lock, flags);
+ return 0;
+ }
/* smooth out the fanspeed increase/decrease */
if (!immediate && duty >= 0) {
@@ -73,8 +75,15 @@ nouveau_fan_update(struct nouveau_fan *fan, bool immediate, int target)
nv_debug(therm, "FAN update: %d\n", duty);
ret = fan->set(therm, duty);
- if (ret)
- goto done;
+ if (ret) {
+ spin_unlock_irqrestore(&fan->lock, flags);
+ return ret;
+ }
+
+ /* fan speed updated, drop the fan lock before grabbing the
+ * alarm-scheduling lock and risking a deadlock
+ */
+ spin_unlock_irqrestore(&fan->lock, flags);
/* schedule next fan update, if not at target speed already */
if (list_empty(&fan->alarm.head) && target != duty) {
@@ -92,8 +101,6 @@ nouveau_fan_update(struct nouveau_fan *fan, bool immediate, int target)
ptimer->alarm(ptimer, delay * 1000 * 1000, &fan->alarm);
}
-done:
- spin_unlock_irqrestore(&fan->lock, flags);
return ret;
}