backlight: Rework backlight/fb interaction simplifying, lots
fb_info->bl_mutex is badly thought out and the backlight class doesn't
need it if the framebuffer/backlight register/unregister order is
consistent, particularly after the backlight locking fixes.
Fix the drivers to use the order:
backlight_device_register()
register_framebuffer()
unregister_framebuffer()
backlight_device_unregister()
and turn bl_mutex into a lock for the bl_curve data only.
Signed-off-by: Richard Purdie <rpurdie@rpsys.net>
diff --git a/include/linux/fb.h b/include/linux/fb.h
index bf7158b..be913ec 100644
--- a/include/linux/fb.h
+++ b/include/linux/fb.h
@@ -769,16 +769,13 @@
struct fb_videomode *mode; /* current mode */
#ifdef CONFIG_FB_BACKLIGHT
- /* Lock ordering:
- * bl_mutex (protects bl_dev and bl_curve)
- * bl_dev->sem (backlight class)
- */
- struct mutex bl_mutex;
-
/* assigned backlight device */
+ /* set before framebuffer registration,
+ remove after unregister */
struct backlight_device *bl_dev;
/* Backlight level curve */
+ struct mutex bl_curve_mutex;
u8 bl_curve[FB_BACKLIGHT_LEVELS];
#endif