[PATCH 4.4 022/210] Thermal: Ignore invalid trip points

From: Greg Kroah-Hartman
Date: Sun Apr 10 2016 - 16:04:36 EST


4.4-stable review patch. If anyone has any objections, please let me know.

------------------

From: Zhang Rui <rui.zhang@xxxxxxxxx>

commit 81ad4276b505e987dd8ebbdf63605f92cd172b52 upstream.

In some cases, platform thermal driver may report invalid trip points,
thermal core should not take any action for these trip points.

This fixed a regression that bogus trip point starts to screw up thermal
control on some Lenovo laptops, after
commit bb431ba26c5cd0a17c941ca6c3a195a3a6d5d461
Author: Zhang Rui <rui.zhang@xxxxxxxxx>
Date: Fri Oct 30 16:31:47 2015 +0800

Thermal: initialize thermal zone device correctly

After thermal zone device registered, as we have not read any
temperature before, thus tz->temperature should not be 0,
which actually means 0C, and thermal trend is not available.
In this case, we need specially handling for the first
thermal_zone_device_update().

Both thermal core framework and step_wise governor is
enhanced to handle this. And since the step_wise governor
is the only one that uses trends, so it's the only thermal
governor that needs to be updated.

Tested-by: Manuel Krause <manuelkrause@xxxxxxxxxxxx>
Tested-by: szegad <szegadlo@xxxxxxxxxxxxxx>
Tested-by: prash <prash.n.rao@xxxxxxxxx>
Tested-by: amish <ammdispose-arch@xxxxxxxxx>
Tested-by: Matthias <morpheusxyz123@xxxxxxxx>
Reviewed-by: Javi Merino <javi.merino@xxxxxxx>
Signed-off-by: Zhang Rui <rui.zhang@xxxxxxxxx>
Signed-off-by: Chen Yu <yu.c.chen@xxxxxxxxx>

Link: https://bugzilla.redhat.com/show_bug.cgi?id=1317190
Link: https://bugzilla.kernel.org/show_bug.cgi?id=114551
Signed-off-by: Zhang Rui <rui.zhang@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
drivers/thermal/thermal_core.c | 13 ++++++++++++-
include/linux/thermal.h | 2 ++
2 files changed, 14 insertions(+), 1 deletion(-)

--- a/drivers/thermal/thermal_core.c
+++ b/drivers/thermal/thermal_core.c
@@ -454,6 +454,10 @@ static void handle_thermal_trip(struct t
{
enum thermal_trip_type type;

+ /* Ignore disabled trip points */
+ if (test_bit(trip, &tz->trips_disabled))
+ return;
+
tz->ops->get_trip_type(tz, trip, &type);

if (type == THERMAL_TRIP_CRITICAL || type == THERMAL_TRIP_HOT)
@@ -1796,6 +1800,7 @@ struct thermal_zone_device *thermal_zone
{
struct thermal_zone_device *tz;
enum thermal_trip_type trip_type;
+ int trip_temp;
int result;
int count;
int passive = 0;
@@ -1867,9 +1872,15 @@ struct thermal_zone_device *thermal_zone
goto unregister;

for (count = 0; count < trips; count++) {
- tz->ops->get_trip_type(tz, count, &trip_type);
+ if (tz->ops->get_trip_type(tz, count, &trip_type))
+ set_bit(count, &tz->trips_disabled);
if (trip_type == THERMAL_TRIP_PASSIVE)
passive = 1;
+ if (tz->ops->get_trip_temp(tz, count, &trip_temp))
+ set_bit(count, &tz->trips_disabled);
+ /* Check for bogus trip points */
+ if (trip_temp == 0)
+ set_bit(count, &tz->trips_disabled);
}

if (!passive) {
--- a/include/linux/thermal.h
+++ b/include/linux/thermal.h
@@ -156,6 +156,7 @@ struct thermal_attr {
* @trip_hyst_attrs: attributes for trip points for sysfs: trip hysteresis
* @devdata: private pointer for device private data
* @trips: number of trip points the thermal zone supports
+ * @trips_disabled; bitmap for disabled trips
* @passive_delay: number of milliseconds to wait between polls when
* performing passive cooling.
* @polling_delay: number of milliseconds to wait between polls when
@@ -191,6 +192,7 @@ struct thermal_zone_device {
struct thermal_attr *trip_hyst_attrs;
void *devdata;
int trips;
+ unsigned long trips_disabled; /* bitmap for disabled trips */
int passive_delay;
int polling_delay;
int temperature;