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authorLen Brown <len.brown@intel.com>2007-08-12 00:12:54 -0400
committerLen Brown <len.brown@intel.com>2007-08-12 00:12:54 -0400
commitf8707ec9643769957065405b5090e4aa64fd8214 (patch)
tree454f1b6a981884072389cfdf3ce25e9636a2b39c /drivers/acpi
parentf54871456162aff557d57bec51639b1288d4a84b (diff)
ACPI: thermal: create "thermal.act=" to disable or override active trip point
thermal.act=-1 disables all active trip points in all ACPI thermal zones. thermal.act=C, where C > 0, overrides all lowest temperature active trip points in all thermal zones to C degrees Celsius. Raising this trip-point may allow you to keep your system silent up to a higher temperature. However, it will not allow you to raise the lowest temperature trip point above the next higher trip point (if there is one). Lowering this trip point may kick in the fan sooner. Note that overriding this trip-point will disable any BIOS attempts to implement hysteresis around the lowest temperature trip point. This may result in the fan starting and stopping frequently if temperature frequently crosses C. WARNING: raising trip points above the manufacturer's defaults may cause the system to run at higher temperature and shorten its life. Signed-off-by: Len Brown <len.brown@intel.com>
Diffstat (limited to 'drivers/acpi')
-rw-r--r--drivers/acpi/thermal.c34
1 files changed, 30 insertions, 4 deletions
diff --git a/drivers/acpi/thermal.c b/drivers/acpi/thermal.c
index 57d05ff44dd..3521c37bbd3 100644
--- a/drivers/acpi/thermal.c
+++ b/drivers/acpi/thermal.c
@@ -74,6 +74,10 @@ MODULE_AUTHOR("Paul Diefenbaugh");
MODULE_DESCRIPTION("ACPI Thermal Zone Driver");
MODULE_LICENSE("GPL");
+static int act;
+module_param(act, int, 0644);
+MODULE_PARM_DESC(act, "Disable or override all lowest active trip points.\n");
+
static int tzp;
module_param(tzp, int, 0444);
MODULE_PARM_DESC(tzp, "Thermal zone polling frequency, in 1/10 seconds.\n");
@@ -405,11 +409,33 @@ static int acpi_thermal_get_trip_points(struct acpi_thermal *tz)
char name[5] = { '_', 'A', 'C', ('0' + i), '\0' };
- status =
- acpi_evaluate_integer(tz->device->handle, name, NULL,
- &tz->trips.active[i].temperature);
- if (ACPI_FAILURE(status))
+ if (act == -1)
+ break; /* disable all active trip points */
+
+ status = acpi_evaluate_integer(tz->device->handle,
+ name, NULL, &tz->trips.active[i].temperature);
+
+ if (ACPI_FAILURE(status)) {
+ if (i == 0) /* no active trip points */
+ break;
+ if (act <= 0) /* no override requested */
+ break;
+ if (i == 1) { /* 1 trip point */
+ tz->trips.active[0].temperature =
+ CELSIUS_TO_KELVIN(act);
+ } else { /* multiple trips */
+ /*
+ * Don't allow override higher than
+ * the next higher trip point
+ */
+ tz->trips.active[i - 1].temperature =
+ (tz->trips.active[i - 2].temperature <
+ CELSIUS_TO_KELVIN(act) ?
+ tz->trips.active[i - 2].temperature :
+ CELSIUS_TO_KELVIN(act));
+ }
break;
+ }
name[2] = 'L';
status =