diff options
authorLen Brown <>2007-08-12 00:12:35 -0400
committerLen Brown <>2007-08-12 00:12:35 -0400
commita70cdc5200b0eb9fc3ef64efb29baac9b2cf2431 (patch)
parent730ff34de766a6fddee25ac1c32bc49c1a2fd758 (diff)
ACPI: thermal: create "thermal.psv=" to override passive trip points
"thermal.psv=-1" disables passive trip points for all ACPI thermal zones. "thermal.psv=C", where 'C' is degrees Celsius, overrides all existing passive trip points for all ACPI thermal zones. thermal.psv is checked at module load time, and in response to trip-point change events. Note that if the system does not deliver thermal zone temperature change events near the new trip-point, then it will not be noticed. To force your custom trip point to be noticed, you may need to enable polling: eg. thermal.tzp=3000 invokes polling every 5 minutes. Note that once passive thermal throttling is invoked, it has its own internal Thermal Sampling Period (_TSP), that is unrelated to _TZP. WARNING: disabling or raising a thermal trip point may result in increased running temperature and shorter hardware lifetime on some systems. Signed-off-by: Len Brown <>
2 files changed, 18 insertions, 3 deletions
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index ed7d7913af8..52e1c2d26a2 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -1823,6 +1823,10 @@ and is between 256 and 4096 characters. It is defined in the file [HW,ACPI]
1: disable ACPI thermal control
+ thermal.psv= [HW,ACPI]
+ -1: disable all passive trip points
+ <degrees C>: override all passive trip points to this value
thermal.tzp= [HW,ACPI]
Specify global default ACPI thermal zone polling rate
<deci-seconds>: poll all this frequency
diff --git a/drivers/acpi/thermal.c b/drivers/acpi/thermal.c
index b6b3bec8454..74e25be8abc 100644
--- a/drivers/acpi/thermal.c
+++ b/drivers/acpi/thermal.c
@@ -82,6 +82,10 @@ static int off;
module_param(off, int, 0);
MODULE_PARM_DESC(off, "Set to disable ACPI thermal support.\n");
+static int psv;
+module_param(psv, int, 0644);
+MODULE_PARM_DESC(psv, "Disable or override all passive trip points.\n");
static int acpi_thermal_add(struct acpi_device *device);
static int acpi_thermal_remove(struct acpi_device *device, int type);
static int acpi_thermal_resume(struct acpi_device *device);
@@ -343,9 +347,16 @@ static int acpi_thermal_get_trip_points(struct acpi_thermal *tz)
/* Passive: Processors (optional) */
- status =
- acpi_evaluate_integer(tz->device->handle, "_PSV", NULL,
- &tz->trips.passive.temperature);
+ if (psv == -1) {
+ status = AE_SUPPORT;
+ } else if (psv > 0) {
+ tz->trips.passive.temperature = CELSIUS_TO_KELVIN(psv);
+ status = AE_OK;
+ } else {
+ status = acpi_evaluate_integer(tz->device->handle,
+ "_PSV", NULL, &tz->trips.passive.temperature);
+ }
if (ACPI_FAILURE(status)) {
tz->trips.passive.flags.valid = 0;
ACPI_DEBUG_PRINT((ACPI_DB_INFO, "No passive threshold\n"));