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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
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>
-rw-r--r--Documentation/kernel-parameters.txt4
-rw-r--r--drivers/acpi/thermal.c34
2 files changed, 34 insertions, 4 deletions
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index 4c7d2774d2a4..06db892b558a 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -1820,6 +1820,10 @@ and is between 256 and 4096 characters. It is defined in the file
thash_entries= [KNL,NET]
Set number of hash buckets for TCP connection
+ thermal.act= [HW,ACPI]
+ -1: disable all active trip points in all thermal zones
+ <degrees C>: override all lowest active 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 57d05ff44dd1..3521c37bbd33 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 =