ddk: 3.17-rc1

git-svn-id: svn://kolibrios.org@5056 a494cfbc-eb01-0410-851d-a64ba20cac60

drivers/include/linux/backlight.h

@@ -7,4 +7,36 @@
 
 #ifndef _LINUX_BACKLIGHT_H
 #define _LINUX_BACKLIGHT_H
+/* Notes on locking:
+ *
+ * backlight_device->ops_lock is an internal backlight lock protecting the
+ * ops pointer and no code outside the core should need to touch it.
+ *
+ * Access to update_status() is serialised by the update_lock mutex since
+ * most drivers seem to need this and historically get it wrong.
+ *
+ * Most drivers don't need locking on their get_brightness() method.
+ * If yours does, you need to implement it in the driver. You can use the
+ * update_lock mutex if appropriate.
+ *
+ * Any other use of the locks below is probably wrong.
+ */
+
+enum backlight_update_reason {
+	BACKLIGHT_UPDATE_HOTKEY,
+	BACKLIGHT_UPDATE_SYSFS,
+};
+
+enum backlight_type {
+	BACKLIGHT_RAW = 1,
+	BACKLIGHT_PLATFORM,
+	BACKLIGHT_FIRMWARE,
+	BACKLIGHT_TYPE_MAX,
+};
+
+enum backlight_notification {
+	BACKLIGHT_REGISTERED,
+	BACKLIGHT_UNREGISTERED,
+};
+
 #endif