diff --git a/Documentation/thermal/power_allocator.txt b/Documentation/thermal/power_allocator.txt
index c3797b529991f03ad0673cc5a249931a7a370f09..a1ce2235f121c29f3520e5504d06c22c60030f99 100644
--- a/Documentation/thermal/power_allocator.txt
+++ b/Documentation/thermal/power_allocator.txt
@@ -4,7 +4,7 @@ Power allocator governor tunables
Trip points
-----------
-The governor requires the following two passive trip points:
+The governor works optimally with the following two passive trip points:
1. "switch on" trip point: temperature above which the governor
control loop starts operating. This is the first passive trip
diff --git a/drivers/thermal/power_allocator.c b/drivers/thermal/power_allocator.c
index 51473473f15481eba0e08a01cd992cb32a8100d9..ea57759eb095c5b4f6a75cc6eff463862516936e 100644
--- a/drivers/thermal/power_allocator.c
+++ b/drivers/thermal/power_allocator.c
@@ -24,6 +24,8 @@
#include "thermal_core.h"
+#define INVALID_TRIP -1
+
#define FRAC_BITS 10
#define int_to_frac(x) ((x) << FRAC_BITS)
#define frac_to_int(x) ((x) >> FRAC_BITS)
@@ -61,6 +63,8 @@ static inline s64 div_frac(s64 x, s64 y)
* Used to calculate the derivative term.
* @trip_switch_on: first passive trip point of the thermal zone. The
* governor switches on when this trip point is crossed.
+ * If the thermal zone only has one passive trip point,
+ * @trip_switch_on should be INVALID_TRIP.
* @trip_max_desired_temperature: last passive trip point of the thermal
* zone. The temperature we are
* controlling for.
@@ -432,43 +436,66 @@ unlock:
return ret;
}
-static int get_governor_trips(struct thermal_zone_device *tz,
- struct power_allocator_params *params)
+/**
+ * get_governor_trips() - get the number of the two trip points that are key for this governor
+ * @tz: thermal zone to operate on
+ * @params: pointer to private data for this governor
+ *
+ * The power allocator governor works optimally with two trips points:
+ * a "switch on" trip point and a "maximum desired temperature". These
+ * are defined as the first and last passive trip points.
+ *
+ * If there is only one trip point, then that's considered to be the
+ * "maximum desired temperature" trip point and the governor is always
+ * on. If there are no passive or active trip points, then the
+ * governor won't do anything. In fact, its throttle function
+ * won't be called at all.
+ */
+static void get_governor_trips(struct thermal_zone_device *tz,
+ struct power_allocator_params *params)
{
- int i, ret, last_passive;
+ int i, last_active, last_passive;
bool found_first_passive;
found_first_passive = false;
- last_passive = -1;
- ret = -EINVAL;
+ last_active = INVALID_TRIP;
+ last_passive = INVALID_TRIP;
for (i = 0; i < tz->trips; i++) {
enum thermal_trip_type type;
+ int ret;
ret = tz->ops->get_trip_type(tz, i, &type);
- if (ret)
- return ret;
+ if (ret) {
+ dev_warn(&tz->device,
+ "Failed to get trip point %d type: %d\n", i,
+ ret);
+ continue;
+ }
- if (!found_first_passive) {
- if (type == THERMAL_TRIP_PASSIVE) {
+ if (type == THERMAL_TRIP_PASSIVE) {
+ if (!found_first_passive) {
params->trip_switch_on = i;
found_first_passive = true;
+ } else {
+ last_passive = i;
}
- } else if (type == THERMAL_TRIP_PASSIVE) {
- last_passive = i;
+ } else if (type == THERMAL_TRIP_ACTIVE) {
+ last_active = i;
} else {
break;
}
}
- if (last_passive != -1) {
+ if (last_passive != INVALID_TRIP) {
params->trip_max_desired_temperature = last_passive;
- ret = 0;
+ } else if (found_first_passive) {
+ params->trip_max_desired_temperature = params->trip_switch_on;
+ params->trip_switch_on = INVALID_TRIP;
} else {
- ret = -EINVAL;
+ params->trip_switch_on = INVALID_TRIP;
+ params->trip_max_desired_temperature = last_active;
}
-
- return ret;
}
static void reset_pid_controller(struct power_allocator_params *params)
@@ -497,11 +524,10 @@ static void allow_maximum_power(struct thermal_zone_device *tz)
* power_allocator_bind() - bind the power_allocator governor to a thermal zone
* @tz: thermal zone to bind it to
*
- * Check that the thermal zone is valid for this governor, that is, it
- * has two thermal trips. If so, initialize the PID controller
- * parameters and bind it to the thermal zone.
+ * Initialize the PID controller parameters and bind it to the thermal
+ * zone.
*
- * Return: 0 on success, -EINVAL if the trips were invalid or -ENOMEM
+ * Return: 0 on success, -EINVAL if the thermal zone doesn't have tzp or -ENOMEM
* if we ran out of memory.
*/
static int power_allocator_bind(struct thermal_zone_device *tz)
@@ -520,30 +546,23 @@ static int power_allocator_bind(struct thermal_zone_device *tz)
if (!tz->tzp->sustainable_power)
dev_warn(&tz->device, "power_allocator: sustainable_power will be estimated\n");
- ret = get_governor_trips(tz, params);
- if (ret) {
- dev_err(&tz->device,
- "thermal zone %s has wrong trip setup for power allocator\n",
- tz->type);
- goto free;
- }
+ get_governor_trips(tz, params);
- ret = tz->ops->get_trip_temp(tz, params->trip_max_desired_temperature,
- &control_temp);
- if (ret)
- goto free;
+ if (tz->trips > 0) {
+ ret = tz->ops->get_trip_temp(tz,
+ params->trip_max_desired_temperature,
+ &control_temp);
+ if (!ret)
+ estimate_pid_constants(tz, tz->tzp->sustainable_power,
+ params->trip_switch_on,
+ control_temp, false);
+ }
- estimate_pid_constants(tz, tz->tzp->sustainable_power,
- params->trip_switch_on, control_temp, false);
reset_pid_controller(params);
tz->governor_data = params;
return 0;
-
-free:
- kfree(params);
- return ret;
}
static void power_allocator_unbind(struct thermal_zone_device *tz)
@@ -574,13 +593,7 @@ static int power_allocator_throttle(struct thermal_zone_device *tz, int trip)
ret = tz->ops->get_trip_temp(tz, params->trip_switch_on,
&switch_on_temp);
- if (ret) {
- dev_warn(&tz->device,
- "Failed to get switch on temperature: %d\n", ret);
- return ret;
- }
-
- if (current_temp < switch_on_temp) {
+ if (!ret && (current_temp < switch_on_temp)) {
tz->passive = 0;
reset_pid_controller(params);
allow_maximum_power(tz);