2 files changed, 42 insertions, 3 deletions

diff --git a/drivers/thermal/thermal_sys.c b/drivers/thermal/thermal_sys.c
index 70045c12d7df..36ae2f43ee2e 100644
--- a/drivers/thermal/thermal_sys.c
+++ b/drivers/thermal/thermal_sys.c
@@ -41,6 +41,7 @@ MODULE_AUTHOR("Zhang Rui");
 MODULE_DESCRIPTION("Generic thermal management sysfs support");
 MODULE_LICENSE("GPL");
 
+#define THERMAL_NO_TARGET -1UL
 /*
  * This structure is used to describe the behavior of
  * a certain cooling device on a certain trip point
@@ -54,6 +55,7 @@ struct thermal_instance {
         int trip;
         unsigned long upper;    /* Highest cooling state for this trip point */
         unsigned long lower;    /* Lowest cooling state for this trip point */
+        unsigned long target;   /* expected cooling state */
         char attr_name[THERMAL_NAME_LENGTH];
         struct device_attribute attr;
         struct list_head tz_node; /* node in tz->thermal_instances */
@@ -853,6 +855,7 @@ int thermal_zone_bind_cooling_device(struct thermal_zone_device *tz,
         dev->trip = trip;
         dev->upper = upper;
         dev->lower = lower;
+        dev->target = THERMAL_NO_TARGET;
 
         result = get_idr(&tz->idr, &tz->lock, &dev->id);
         if (result)
@@ -990,6 +993,7 @@ thermal_cooling_device_register(char *type, void *devdata,
         strcpy(cdev->type, type);
         INIT_LIST_HEAD(&cdev->thermal_instances);
         cdev->ops = ops;
+        cdev->updated = true;
         cdev->device.class = &thermal_class;
         cdev->devdata = devdata;
         dev_set_name(&cdev->device, "cooling_device%d", cdev->id);
@@ -1081,6 +1085,34 @@ void thermal_cooling_device_unregister(struct
 }
 EXPORT_SYMBOL(thermal_cooling_device_unregister);
 
+static void thermal_cdev_do_update(struct thermal_cooling_device *cdev)
+{
+        struct thermal_instance *instance;
+        unsigned long target = 0;
+
+        /* cooling device is updated*/
+        if (cdev->updated)
+                return;
+
+        /* Make sure cdev enters the deepest cooling state */
+        list_for_each_entry(instance, &cdev->thermal_instances, cdev_node) {
+                if (instance->target == THERMAL_NO_TARGET)
+                        continue;
+                if (instance->target > target)
+                        target = instance->target;
+        }
+        cdev->ops->set_cur_state(cdev, target);
+        cdev->updated = true;
+}
+
+static void thermal_zone_do_update(struct thermal_zone_device *tz)
+{
+        struct thermal_instance *instance;
+
+        list_for_each_entry(instance, &tz->thermal_instances, tz_node)
+                thermal_cdev_do_update(instance->cdev);
+}
+
 /*
  * Cooling algorithm for active trip points
  *
@@ -1138,19 +1170,24 @@ static void thermal_zone_trip_update(struct thermal_zone_device *tz,
                                 cur_state = cur_state > instance->lower ?
                                     (cur_state - 1) : instance->lower;
                         }
-                        cdev->ops->set_cur_state(cdev, cur_state);
+                        instance->target = cur_state;
+                        cdev->updated = false; /* cooling device needs update */
                 }
         } else {        /* below trip */
                 list_for_each_entry(instance, &tz->thermal_instances, tz_node) {
                         if (instance->trip != trip)
                                 continue;
 
+                        /* Do not use the inactive thermal instance */
+                        if (instance->target == THERMAL_NO_TARGET)
+                                continue;
                         cdev = instance->cdev;
                         cdev->ops->get_cur_state(cdev, &cur_state);
 
                         cur_state = cur_state > instance->lower ?
-                                    (cur_state - 1) : instance->lower;
-                        cdev->ops->set_cur_state(cdev, cur_state);
+                                    (cur_state - 1) : THERMAL_NO_TARGET;
+                        instance->target = cur_state;
+                        cdev->updated = false; /* cooling device needs update */
                 }
         }
 
@@ -1211,6 +1248,7 @@ void thermal_zone_device_update(struct thermal_zone_device *tz)
                 }
         }
 
+        thermal_zone_do_update(tz);
         if (tz->forced_passive)
                 thermal_zone_device_passive(tz, temp, tz->forced_passive,
                                             THERMAL_TRIPS_NONE);
diff --git a/include/linux/thermal.h b/include/linux/thermal.h
index 9ae378a4a555..de0515a96f9f 100644
--- a/include/linux/thermal.h
+++ b/include/linux/thermal.h
@@ -94,6 +94,7 @@ struct thermal_cooling_device {
         struct device device;
         void *devdata;
         const struct thermal_cooling_device_ops *ops;
+        bool updated; /* true if the cooling device does not need update */
         struct list_head thermal_instances;
         struct list_head node;
 };