[OEM-5.17][PATCH 1/1] UBUNTU: SAUCE: drm/amd/display: Cap OLED brightness per max frame-average luminance

[Aaron Ma]

From: Roman Li <roman.li at amd.com>

BugLink: https://bugs.launchpad.net/bugs/1978986

[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 at amd.com>
Acked-by: Hamza Mahfooz <hamza.mahfooz at amd.com>
Signed-off-by: Roman Li <roman.li at amd.com>
Link: https://lore.kernel.org/amd-gfx/20220603201147.121817-8-hamza.mahfooz@amd.com
Signed-off-by: Aaron Ma <aaron.ma at canonical.com>
---
 drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

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 f9eadc2f3ccee..c81864d066c2f 100644
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
@@ -2814,7 +2814,7 @@ 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;
@@ -2844,7 +2844,7 @@ 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 /*||
@@ -2872,8 +2872,8 @@ 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
-- 
2.34.1