drm/amd/display: Cap OLED brightness per max frame-average luminance

[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@amd.com>
Acked-by: Hamza Mahfooz <hamza.mahfooz@amd.com>
Signed-off-by: Roman Li <roman.li@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Cc: stable@vger.kernel.org

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 70be67a56673745d5392cd50a2b61f6e23fbb89c..39b425d83bb1a5f52030d14f6bc134ef376bcf0c 100644 (file)
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
@@ -2812,7 +2812,7 @@ static struct drm_mode_config_helper_funcs amdgpu_dm_mode_config_helperfuncs = {
 
 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;
@@ -2842,7 +2842,7 @@ static void update_connector_ext_caps(struct amdgpu_dm_connector *aconnector)
        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 /*||
@@ -2870,8 +2870,8 @@ static void update_connector_ext_caps(struct amdgpu_dm_connector *aconnector)
         * 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