From: Lukasz Majewski <l.majewski@samsung.com>
Date: Wed, 24 Sep 2014 08:27:10 +0000 (+0200)
Subject: thermal: step_wise: fix: Prevent from binary overflow when trend is dropping
X-Git-Url: http://drtracing.org/?a=commitdiff_plain;h=26bb0e9a1a938ec98ee07aa76533f1a711fba706;p=deliverable%2Flinux.git

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>
---

diff --git a/drivers/thermal/step_wise.c b/drivers/thermal/step_wise.c
index f251521baaa2..6705a0d746b3 100644
--- a/drivers/thermal/step_wise.c
+++ b/drivers/thermal/step_wise.c
@@ -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 {