From: Frans Pop <elendil@xxxxxxxxx> 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 Addresses http://bugzilla.kernel.org/show_bug.cgi?id=13918 Signed-off-by: Frans Pop <elendil@xxxxxxxxx> Cc: Matthew Garrett <mjg@xxxxxxxxxx> Cc: Zhang Rui <rui.zhang@xxxxxxxxx> Cc: Len Brown <lenb@xxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- Documentation/thermal/sysfs-api.txt | 1 + drivers/thermal/thermal_sys.c | 6 ++++++ 2 files changed, 7 insertions(+) diff -puN Documentation/thermal/sysfs-api.txt~thermal-add-sanity-check-for-the-passive-attribute Documentation/thermal/sysfs-api.txt --- a/Documentation/thermal/sysfs-api.txt~thermal-add-sanity-check-for-the-passive-attribute +++ a/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 -puN drivers/thermal/thermal_sys.c~thermal-add-sanity-check-for-the-passive-attribute drivers/thermal/thermal_sys.c --- a/drivers/thermal/thermal_sys.c~thermal-add-sanity-check-for-the-passive-attribute +++ a/drivers/thermal/thermal_sys.c @@ -225,6 +225,12 @@ passive_store(struct device *dev, struct 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) { _ -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
