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-rw-r--r--Documentation/thermal/sysfs-api.txt12
-rw-r--r--drivers/thermal/fair_share.c26
-rw-r--r--include/linux/thermal.h9
3 files changed, 36 insertions, 11 deletions
diff --git a/Documentation/thermal/sysfs-api.txt b/Documentation/thermal/sysfs-api.txt
index 3625453ceef6..fc7dfe10778b 100644
--- a/Documentation/thermal/sysfs-api.txt
+++ b/Documentation/thermal/sysfs-api.txt
@@ -129,9 +129,15 @@ temperature) and throttle appropriate devices.
This structure defines the following parameters that are used to bind
a zone with a cooling device for a particular trip point.
.cdev: The cooling device pointer
- .weight: The 'influence' of a particular cooling device on this zone.
- This is on a percentage scale. The sum of all these weights
- (for a particular zone) cannot exceed 100.
+ .weight: The 'influence' of a particular cooling device on this
+ zone. This is relative to the rest of the cooling
+ devices. For example, if all cooling devices have a
+ weight of 1, then they all contribute the same. You can
+ use percentages if you want, but it's not mandatory. A
+ weight of 0 means that this cooling device doesn't
+ contribute to the cooling of this zone unless all cooling
+ devices have a weight of 0. If all weights are 0, then
+ they all contribute the same.
.trip_mask:This is a bit mask that gives the binding relation between
this thermal zone and cdev, for a particular trip point.
If nth bit is set, then the cdev and thermal zone are bound
diff --git a/drivers/thermal/fair_share.c b/drivers/thermal/fair_share.c
index 692f4053f08b..c2c10bbe24d6 100644
--- a/drivers/thermal/fair_share.c
+++ b/drivers/thermal/fair_share.c
@@ -59,13 +59,13 @@ static int get_trip_level(struct thermal_zone_device *tz)
}
static long get_target_state(struct thermal_zone_device *tz,
- struct thermal_cooling_device *cdev, int weight, int level)
+ struct thermal_cooling_device *cdev, int percentage, int level)
{
unsigned long max_state;
cdev->ops->get_max_state(cdev, &max_state);
- return (long)(weight * level * max_state) / (100 * tz->trips);
+ return (long)(percentage * level * max_state) / (100 * tz->trips);
}
/**
@@ -77,7 +77,7 @@ static long get_target_state(struct thermal_zone_device *tz,
*
* Parameters used for Throttling:
* P1. max_state: Maximum throttle state exposed by the cooling device.
- * P2. weight[i]/100:
+ * P2. percentage[i]/100:
* How 'effective' the 'i'th device is, in cooling the given zone.
* P3. cur_trip_level/max_no_of_trips:
* This describes the extent to which the devices should be throttled.
@@ -89,16 +89,32 @@ static long get_target_state(struct thermal_zone_device *tz,
static int fair_share_throttle(struct thermal_zone_device *tz, int trip)
{
struct thermal_instance *instance;
+ int total_weight = 0;
+ int total_instance = 0;
int cur_trip_level = get_trip_level(tz);
list_for_each_entry(instance, &tz->thermal_instances, tz_node) {
+ if (instance->trip != trip)
+ continue;
+
+ total_weight += instance->weight;
+ total_instance++;
+ }
+
+ list_for_each_entry(instance, &tz->thermal_instances, tz_node) {
+ int percentage;
struct thermal_cooling_device *cdev = instance->cdev;
if (instance->trip != trip)
continue;
- instance->target = get_target_state(tz, cdev,
- instance->weight, cur_trip_level);
+ if (!total_weight)
+ percentage = 100 / total_instance;
+ else
+ percentage = (instance->weight * 100) / total_weight;
+
+ instance->target = get_target_state(tz, cdev, percentage,
+ cur_trip_level);
instance->cdev->updated = false;
thermal_cdev_update(cdev);
diff --git a/include/linux/thermal.h b/include/linux/thermal.h
index 00dacd4dfdce..bac0f52c7a1e 100644
--- a/include/linux/thermal.h
+++ b/include/linux/thermal.h
@@ -217,9 +217,12 @@ struct thermal_bind_params {
/*
* This is a measure of 'how effectively these devices can
- * cool 'this' thermal zone. The shall be determined by platform
- * characterization. This is on a 'percentage' scale.
- * See Documentation/thermal/sysfs-api.txt for more information.
+ * cool 'this' thermal zone. It shall be determined by
+ * platform characterization. This value is relative to the
+ * rest of the weights so a cooling device whose weight is
+ * double that of another cooling device is twice as
+ * effective. See Documentation/thermal/sysfs-api.txt for more
+ * information.
*/
int weight;