path: root/drivers/acpi
diff options
authorZhang Rui <rui.zhang@intel.com>2013-04-26 09:19:53 +0000
committerRafael J. Wysocki <rafael.j.wysocki@intel.com>2013-04-26 13:34:40 +0200
commit94a409319561ec1847fd9bf996a2d5843ad00932 (patch)
treeacd86fa824b04e42c310345837d979526e747c23 /drivers/acpi
parent91e13aa37023437c260c85a3f17308052bbfbfa2 (diff)
ACPI / thermal: do not always return THERMAL_TREND_RAISING for active trip points
Commit 4ae46be "Thermal: Introduce thermal_zone_trip_update()" introduced a regression causing the fan to be always on even when the system is idle. My original idea in that commit is that: - when the current temperature is above the trip point, keep the fan on, even if the temperature is dropping. - when the current temperature is below the trip point, turn on the fan when the temperature is raising, turn off the fan when the temperature is dropping. But this is what the code actually does: - when the current temperature is above the trip point, the fan keeps on. - when the current temperature is below the trip point, the fan is always on because thermal_get_trend() in driver/acpi/thermal.c returns THERMAL_TREND_RAISING. Thus the fan keeps running even if the system is idle. Fix this in drivers/acpi/thermal.c. [rjw: Changelog] References: https://bugzilla.kernel.org/show_bug.cgi?id=56591 References: https://bugzilla.kernel.org/show_bug.cgi?id=56601 References: https://bugzilla.kernel.org/show_bug.cgi?id=50041#c45 Signed-off-by: Zhang Rui <rui.zhang@intel.com> Tested-by: Matthias <morpheusxyz123@yahoo.de> Tested-by: Ville Syrjälä <syrjala@sci.fi> Cc: 3.7+ <stable@vger.kernel.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Diffstat (limited to 'drivers/acpi')
1 files changed, 13 insertions, 3 deletions
diff --git a/drivers/acpi/thermal.c b/drivers/acpi/thermal.c
index 8470771e5ea..a33821ca389 100644
--- a/drivers/acpi/thermal.c
+++ b/drivers/acpi/thermal.c
@@ -723,9 +723,19 @@ static int thermal_get_trend(struct thermal_zone_device *thermal,
return -EINVAL;
if (type == THERMAL_TRIP_ACTIVE) {
- /* aggressive active cooling */
- return 0;
+ unsigned long trip_temp;
+ unsigned long temp = KELVIN_TO_MILLICELSIUS(tz->temperature,
+ tz->kelvin_offset);
+ if (thermal_get_trip_temp(thermal, trip, &trip_temp))
+ return -EINVAL;
+ if (temp > trip_temp) {
+ return 0;
+ } else {
+ /* Fall back on default trend */
+ return -EINVAL;
+ }