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authorLen Brown <len.brown@intel.com>2007-08-14 15:49:32 -0400
committerLen Brown <len.brown@intel.com>2007-08-14 15:49:32 -0400
commitc52a7419af18594426bc601d1ea346dbbcf71e28 (patch)
treeb964b0de460e3508e092efa3b69fbc7267aef735
parent3c1d36da1d5ed36979340efd233ddaacc45b0a02 (diff)
downloadlinux-linaro-c52a7419af18594426bc601d1ea346dbbcf71e28.tar.gz
ACPI: thermal: create "thermal.crt=C" bootparam
Some hardware will malfunction at a temperature below the BIOS provided critical shutdown threshold. This hook allows moving the critical trip points down to a temperature which provokes a graceful shutdown before the hardware malfunction. http://bugzilla.kernel.org/show_bug.cgi?id=8884 WARNING: A trip-point override will not get noticed until the system delivers a temperature change event, or unless thermal zone polling is enabled. eg. "thermal.tzp=10" Signed-off-by: Len Brown <len.brown@intel.com>
-rw-r--r--Documentation/kernel-parameters.txt4
-rw-r--r--drivers/acpi/thermal.c18
2 files changed, 22 insertions, 0 deletions
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index 975f029be25..18dcfdd29df 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -1826,6 +1826,10 @@ and is between 256 and 4096 characters. It is defined in the file
-1: disable all active trip points in all thermal zones
<degrees C>: override all lowest active trip points
+ thermal.crt= [HW,ACPI]
+ -1: disable all critical trip points in all thermal zones
+ <degrees C>: lower all critical trip points
+
thermal.nocrt= [HW,ACPI]
Set to disable actions on ACPI thermal zone
critical and hot trip points.
diff --git a/drivers/acpi/thermal.c b/drivers/acpi/thermal.c
index 9b31f36481d..4c420feba20 100644
--- a/drivers/acpi/thermal.c
+++ b/drivers/acpi/thermal.c
@@ -79,6 +79,10 @@ static int act;
module_param(act, int, 0644);
MODULE_PARM_DESC(act, "Disable or override all lowest active trip points.");
+static int crt;
+module_param(crt, int, 0644);
+MODULE_PARM_DESC(crt, "Disable or lower all critical trip points.");
+
static int tzp;
module_param(tzp, int, 0444);
MODULE_PARM_DESC(tzp, "Thermal zone polling frequency, in 1/10 seconds.");
@@ -340,6 +344,20 @@ static int acpi_thermal_get_trip_points(struct acpi_thermal *tz)
tz->trips.critical.temperature));
}
+ if (tz->trips.critical.flags.valid == 1) {
+ if (crt == -1) {
+ tz->trips.critical.flags.valid = 0;
+ } else if (crt > 0) {
+ unsigned long crt_k = CELSIUS_TO_KELVIN(crt);
+
+ /*
+ * Allow override to lower critical threshold
+ */
+ if (crt_k < tz->trips.critical.temperature)
+ tz->trips.critical.temperature = crt_k;
+ }
+ }
+
/* Critical Sleep (optional) */
status =