c5b53d1281
[Why] The original logic is to update eDP's backlight level on every amdgpu dm atomic commit, which causes excessive DMUB write. As a result, when playing game or moving window around, DMUB timeout and system lagging are observed. [How] We only need to update eDP's backlight level when current level doesn't match requested level. Signed-off-by: Zhan Liu <zhan.liu@amd.com> Reviewed-by: Alex Deucher <alexander.deucher@amd.com> Signed-off-by: Alex Deucher <alexander.deucher@amd.com>