bd->props.brightness doesn't reflect the actual backlight level. Always invoke backlight_update_status when users want to change the backlight. For setups where brightness change is an expensive operation, this could be done in the driver rather than the core. http://bugzilla.kernel.org/show_bug.cgi?id=12249 Signed-off-by: Zhang Rui <rui.zhang@xxxxxxxxx> --- drivers/video/backlight/backlight.c | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-) Index: linux-2.6/drivers/video/backlight/backlight.c =================================================================== --- linux-2.6.orig/drivers/video/backlight/backlight.c +++ linux-2.6/drivers/video/backlight/backlight.c @@ -134,10 +134,8 @@ static ssize_t backlight_store_brightnes else { pr_debug("backlight: set brightness to %d\n", brightness); - if (bd->props.brightness != brightness) { - bd->props.brightness = brightness; - backlight_update_status(bd); - } + bd->props.brightness = brightness; + backlight_update_status(bd); rc = count; } } -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html