diff options
| author | Frans Pop <elendil@planet.nl> | 2009-10-26 08:39:02 +0100 |
|---|---|---|
| committer | Len Brown <len.brown@intel.com> | 2009-11-05 18:18:10 -0500 |
| commit | 3d8e3ad879441ae14c5957b933028daf39d252b0 (patch) | |
| tree | 33f81135d8a8518e2507bc1db51b4adf29d60e41 | |
| parent | 7fb2616e249184e217f9818a7662596165710ea4 (diff) | |
| download | linux-3d8e3ad879441ae14c5957b933028daf39d252b0.tar.gz linux-3d8e3ad879441ae14c5957b933028daf39d252b0.tar.bz2 linux-3d8e3ad879441ae14c5957b933028daf39d252b0.zip | |
thermal: add sanity check for the passive attribute
Values below 1000 milli-celsius don't make sense and can cause the
system to go into a thermal heart attack: the actual temperature
will always be lower and thus the system will be throttled down to
its lowest setting.
An additional problem is that values below 1000 will show as 0 in
/proc/acpi/thermal/TZx/trip_points:passive.
cat passive
0
echo -n 90 >passive
bash: echo: write error: Invalid argument
echo -n 90000 >passive
cat passive
90000
Signed-off-by: Frans Pop <elendil@planet.nl>
Acked-by: Zhang Rui <rui.zhang@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Len Brown <len.brown@intel.com>
| -rw-r--r-- | Documentation/thermal/sysfs-api.txt | 1 | ||||
| -rw-r--r-- | drivers/thermal/thermal_sys.c | 6 |
2 files changed, 7 insertions, 0 deletions
diff --git a/Documentation/thermal/sysfs-api.txt b/Documentation/thermal/sysfs-api.txt index a87dc277a5ca..cb3d15bc1aeb 100644 --- a/Documentation/thermal/sysfs-api.txt +++ b/Documentation/thermal/sysfs-api.txt @@ -206,6 +206,7 @@ passive passive trip point for the zone. Activation is done by polling with an interval of 1 second. Unit: millidegrees Celsius + Valid values: 0 (disabled) or greater than 1000 RW, Optional ***************************** diff --git a/drivers/thermal/thermal_sys.c b/drivers/thermal/thermal_sys.c index 6f8d8f971212..310e40ab00b6 100644 --- a/drivers/thermal/thermal_sys.c +++ b/drivers/thermal/thermal_sys.c @@ -225,6 +225,12 @@ passive_store(struct device *dev, struct device_attribute *attr, if (!sscanf(buf, "%d\n", &state)) return -EINVAL; + /* sanity check: values below 1000 millicelcius don't make sense + * and can cause the system to go into a thermal heart attack + */ + if (state && state < 1000) + return -EINVAL; + if (state && !tz->forced_passive) { mutex_lock(&thermal_list_lock); list_for_each_entry(cdev, &thermal_cdev_list, node) { |