thermal: step_wise: fix: Prevent from binary overflow when trend is dropping

It turns out that some boards can have instance->lower greater than 0 and
when thermal trend is dropping it results with next_target equal to -1.

Since the next_target is defined as unsigned long it is interpreted as
0xFFFFFFFF and larger than instance->upper.
As a result the next_target is set to instance->upper which ramps up to
maximal cooling device target when the temperature is steadily decreasing.

Signed-off-by: Lukasz Majewski <l.majewski@samsung.com>
Signed-off-by: Zhang Rui <rui.zhang@intel.com>
This commit is contained in:
Lukasz Majewski 2014-09-24 10:27:10 +02:00 committed by Zhang Rui
parent 52addcf9d6
commit 26bb0e9a1a

View File

@ -76,7 +76,7 @@ static unsigned long get_target_state(struct thermal_instance *instance,
next_target = instance->upper;
break;
case THERMAL_TREND_DROPPING:
if (cur_state == instance->lower) {
if (cur_state <= instance->lower) {
if (!throttle)
next_target = THERMAL_NO_TARGET;
} else {