Commit a70cdc52 authored by Len Brown's avatar Len Brown
Browse files

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: default avatarLen Brown <len.brown@intel.com>
parent 730ff34d

Documentation/kernel-parameters.txt

+4 −0
Original line number Diff line number Diff line
@@ -1823,6 +1823,10 @@ and is between 256 and 4096 characters. It is defined in the file 
	thermal.off=	[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

drivers/acpi/thermal.c

+14 −3
Original line number Diff line number Diff line
@@ -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"));

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