Some systems report zero AC/DC brightness levels during backlight initialization, causing the panel brightness to start at the minimum level on boot.
Only use the firmware brightness levels when both AC and DC values are non-zero Signed-off-by: Edson Juliano Drosdeck <[email protected]> --- drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c index 5fc5d5608506..f947ce2a8625 100644 --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c @@ -5380,7 +5380,9 @@ amdgpu_dm_register_backlight_device(struct amdgpu_dm_connector *aconnector) } caps = &dm->backlight_caps[aconnector->bl_idx]; - if (get_brightness_range(caps, &min, &max)) { + if (get_brightness_range(caps, &min, &max) && + caps->ac_level > 0 && + caps->dc_level > 0) { if (power_supply_is_system_supplied() > 0) props.brightness = DIV_ROUND_CLOSEST((max - min) * caps->ac_level, 100); else -- 2.47.3
