1 files changed, 12 insertions, 7 deletions

diff --git a/drivers/base/power/qos.c b/drivers/base/power/qos.c
index 71855570922d..fd849a2c4fa8 100644
--- a/drivers/base/power/qos.c
+++ b/drivers/base/power/qos.c
@@ -352,21 +352,26 @@ EXPORT_SYMBOL_GPL(dev_pm_qos_remove_request);
  *
  * Will register the notifier into a notification chain that gets called
  * upon changes to the target value for the device.
+ *
+ * If the device's constraints object doesn't exist when this routine is called,
+ * it will be created (or error code will be returned if that fails).
  */
 int dev_pm_qos_add_notifier(struct device *dev, struct notifier_block *notifier)
 {
-        int retval = 0;
+        int ret = 0;
 
         mutex_lock(&dev_pm_qos_mtx);
 
-        /* Silently return if the constraints object is not present. */
-        if (dev->power.constraints)
-                retval = blocking_notifier_chain_register(
-                                dev->power.constraints->notifiers,
-                                notifier);
+        if (!dev->power.constraints)
+                ret = dev->power.power_state.event != PM_EVENT_INVALID ?
+                        dev_pm_qos_constraints_allocate(dev) : -ENODEV;
+
+        if (!ret)
+                ret = blocking_notifier_chain_register(
+                                dev->power.constraints->notifiers, notifier);
 
         mutex_unlock(&dev_pm_qos_mtx);
-        return retval;
+        return ret;
 }
 EXPORT_SYMBOL_GPL(dev_pm_qos_add_notifier);