thermal.act=-1 disables all active trip points
in all ACPI thermal zones.
thermal.act=C, where C > 0, overrides all first active trip points
in all thermal zones to C degrees Celcius.
Note, overriding this trip-point will disable any BIOS attempts
to implement hysterisis around AC0, and may result in the fan
starting and stopping frequently if temperature frequently crosses C.
Signed-off-by: Len Brown <len.brown@xxxxxxxxx>
---
Documentation/kernel-parameters.txt | 4 ++++
drivers/acpi/thermal.c | 20 ++++++++++++++++----
2 files changed, 20 insertions(+), 4 deletions(-)
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index 897bb63..a82d46f 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 1642980..2b48ab9 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 +409,19 @@ 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)) {
+ /* override last valid trip point */
+ if ((i > 0) && (act > 0))
+ tz->trips.active[i - 1].temperature =
+ CELSIUS_TO_KELVIN(act);
break;
+ }
name[2] = 'L';
status =
--
1.5.3.rc4.29.g74276
-
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