From: Roman Li <roman.li@xxxxxxx> commit 4fd17f2ac0aa4e48823ac2ede5b050fb70300bf4 upstream. [Why] For OLED eDP the Display Manager uses max_cll value as a limit for brightness control. max_cll defines the content light luminance for individual pixel. Whereas max_fall defines frame-average level luminance. The user may not observe the difference in brightness in between max_fall and max_cll. That negatively impacts the user experience. [How] Use max_fall value instead of max_cll as a limit for brightness control. Reviewed-by: Rodrigo Siqueira <Rodrigo.Siqueira@xxxxxxx> Acked-by: Hamza Mahfooz <hamza.mahfooz@xxxxxxx> Signed-off-by: Roman Li <roman.li@xxxxxxx> Tested-by: Daniel Wheeler <daniel.wheeler@xxxxxxx> Signed-off-by: Alex Deucher <alexander.deucher@xxxxxxx> Cc: stable@xxxxxxxxxxxxxxx Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c @@ -2417,7 +2417,7 @@ static struct drm_mode_config_helper_fun static void update_connector_ext_caps(struct amdgpu_dm_connector *aconnector) { - u32 max_cll, min_cll, max, min, q, r; + u32 max_avg, min_cll, max, min, q, r; struct amdgpu_dm_backlight_caps *caps; struct amdgpu_display_manager *dm; struct drm_connector *conn_base; @@ -2447,7 +2447,7 @@ static void update_connector_ext_caps(st caps = &dm->backlight_caps[i]; caps->ext_caps = &aconnector->dc_link->dpcd_sink_ext_caps; caps->aux_support = false; - max_cll = conn_base->hdr_sink_metadata.hdmi_type1.max_cll; + max_avg = conn_base->hdr_sink_metadata.hdmi_type1.max_fall; min_cll = conn_base->hdr_sink_metadata.hdmi_type1.min_cll; if (caps->ext_caps->bits.oled == 1 /*|| @@ -2475,8 +2475,8 @@ static void update_connector_ext_caps(st * The results of the above expressions can be verified at * pre_computed_values. */ - q = max_cll >> 5; - r = max_cll % 32; + q = max_avg >> 5; + r = max_avg % 32; max = (1 << q) * pre_computed_values[r]; // min luminance: maxLum * (CV/255)^2 / 100