[PATCH 1/1] thermal: Check cooling device's current state before declaring it inactive

[Alexander Lam <lambchop468@gmail.com>]

It is possible for a cooling device to become active in between calls to
the thermal governor. An example of this is the acerhdf driver, which
can hand control of the cooling device over to the system firmware. Upon
returning control back to the thermal system, the cooling device might
be running again, so checking the current state of the cooling device is
required.

Signed-off-by: Alexander Lam <lambchop468@gmail.com>
---
 drivers/thermal/step_wise.c | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/drivers/thermal/step_wise.c b/drivers/thermal/step_wise.c
index 0cd5e9f..0eeb709 100644
--- a/drivers/thermal/step_wise.c
+++ b/drivers/thermal/step_wise.c
@@ -94,16 +94,21 @@ static void update_instance_for_dethrottle(struct thermal_zone_device *tz,
 	unsigned long cur_state;
 
 	list_for_each_entry(instance, &tz->thermal_instances, tz_node) {
-		if (instance->trip != trip ||
-			instance->target == THERMAL_NO_TARGET)
+		if (instance->trip != trip)
 			continue;
 
 		cdev = instance->cdev;
 		cdev->ops->get_cur_state(cdev, &cur_state);
 
-		instance->target = cur_state > instance->lower ?
+		cur_state = cur_state > instance->lower ?
 			    (cur_state - 1) : THERMAL_NO_TARGET;
 
+		if (cur_state == THERMAL_NO_TARGET &&
+					instance->target == THERMAL_NO_TARGET)
+			continue;
+
+		instance->target = cur_state;
+
 		/* Deactivate a passive thermal instance */
 		if (instance->target == THERMAL_NO_TARGET)
 			update_passive_instance(tz, trip_type, -1);
-- 
1.8.0.2