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

stable inclusion
from stable-v5.10.124
commit e27430c1f1ed957ece93efbe7907263f996179be
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I5L6E7

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=e27430c1f1ed957ece93efbe7907263f996179be

--------------------------------

commit 4fd17f2a 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: NRodrigo Siqueira <Rodrigo.Siqueira@amd.com>
Acked-by: NHamza Mahfooz <hamza.mahfooz@amd.com>
Signed-off-by: NRoman Li <roman.li@amd.com>
Tested-by: NDaniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>
Cc: stable@vger.kernel.org
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>
Reviewed-by: NWei Li <liwei391@huawei.com>

drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c

@@ -2141,7 +2141,7 @@ 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;
@@ -2164,7 +2164,7 @@ static void update_connector_ext_caps(struct amdgpu_dm_connector *aconnector)
 	caps = &dm->backlight_caps;
 	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 /*||
@@ -2192,8 +2192,8 @@ 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