[patch 22/33] ACPI: Reject below-freezing temperatures as invalid critical temperatures

Greg KH
2008-08-04T20:28:58Z

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2.6.25-stable review patch. If anyone has any objections, please let us
know.

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From: Arjan van de Ven <arjan@linux.intel.com>

commit a39a2d7c72b358c6253a2ec28e17b023b7f6f41c upstream

My laptop thinks that it's a good idea to give -73C as the critical
CPU temperature.... which isn't the best thing since it causes a shutdown
right at bootup.

Temperatures below freezing are clearly invalid critical thresholds
so just reject these as such.

Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Acked-by: Zhang Rui <rui.zhang@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

---
drivers/acpi/thermal.c | 11 +++++++++--
1 file changed, 9 insertions(+), 2 deletions(-)

--- a/drivers/acpi/thermal.c
+++ b/drivers/acpi/thermal.c
@@ -359,10 +359,17 @@ static int acpi_thermal_trips_update(str
if (flag & ACPI_TRIPS_CRITICAL) {
status = acpi_evaluate_integer(tz->device->handle,
"_CRT", NULL, &tz->trips.critical.temperature);
- if (ACPI_FAILURE(status)) {
+ /*
+ * Treat freezing temperatures as invalid as well; some
+ * BIOSes return really low values and cause reboots at startup.
+ * Below zero (Celcius) values clearly aren't right for sure..
+ * ... so lets discard those as invalid.
+ */
+ if (ACPI_FAILURE(status) ||
+ tz->trips.critical.temperature <= 2732) {
tz->trips.critical.flags.valid = 0;
ACPI_EXCEPTION((AE_INFO, status,
- "No critical threshold"));
+ "No or invalid critical threshold"));
return -ENODEV;
} else {
tz->trips.critical.flags.valid = 1;

--