diff --git a/include/linux/backlight.h b/include/linux/backlight.h
index 79ca2da..0f5f578 100644
--- a/include/linux/backlight.h
+++ b/include/linux/backlight.h
@@ -27,6 +27,11 @@
  * Any other use of the locks below is probably wrong.
  */
 
+enum backlight_update_reason {
+	BACKLIGHT_UPDATE_HOTKEY,
+	BACKLIGHT_UPDATE_SYSFS,
+};
+
 struct backlight_device;
 struct fb_info;
 
@@ -100,6 +105,8 @@
 extern struct backlight_device *backlight_device_register(const char *name,
 	struct device *dev, void *devdata, struct backlight_ops *ops);
 extern void backlight_device_unregister(struct backlight_device *bd);
+extern void backlight_force_update(struct backlight_device *bd,
+				   enum backlight_update_reason reason);
 
 #define to_backlight_device(obj) container_of(obj, struct backlight_device, dev)