[PATCH 08/20] drm/amd/display: Clear dpcd_sink_ext_caps if not set

[Alex Hung]

From: Paul Hsieh <paul.hsieh at amd.com>

[WHY]
Some eDP panels' ext caps don't set initial values
and the value of dpcd_addr (0x317) is random.
It means that sometimes the eDP can be OLED, miniLED and etc,
and cause incorrect backlight control interface.

[HOW]
Add remove_sink_ext_caps to remove sink ext caps (HDR, OLED and etc)

Cc: Mario Limonciello <mario.limonciello at amd.com>
Cc: Alex Deucher <alexander.deucher at amd.com>
Cc: stable at vger.kernel.org
Reviewed-by: Anthony Koo <anthony.koo at amd.com>
Acked-by: Alex Hung <alex.hung at amd.com>
Signed-off-by: Paul Hsieh <paul.hsieh at amd.com>
---
 drivers/gpu/drm/amd/display/dc/dc_types.h            | 1 +
 drivers/gpu/drm/amd/display/dc/link/link_detection.c | 3 +++
 2 files changed, 4 insertions(+)

diff --git a/drivers/gpu/drm/amd/display/dc/dc_types.h b/drivers/gpu/drm/amd/display/dc/dc_types.h
index cea666ea66c6..fcb825e4f1bb 100644
--- a/drivers/gpu/drm/amd/display/dc/dc_types.h
+++ b/drivers/gpu/drm/amd/display/dc/dc_types.h
@@ -177,6 +177,7 @@ struct dc_panel_patch {
 	unsigned int disable_fams;
 	unsigned int skip_avmute;
 	unsigned int mst_start_top_delay;
+	unsigned int remove_sink_ext_caps;
 };
 
 struct dc_edid_caps {
diff --git a/drivers/gpu/drm/amd/display/dc/link/link_detection.c b/drivers/gpu/drm/amd/display/dc/link/link_detection.c
index d6f0f857c05a..f2fe523f914f 100644
--- a/drivers/gpu/drm/amd/display/dc/link/link_detection.c
+++ b/drivers/gpu/drm/amd/display/dc/link/link_detection.c
@@ -1088,6 +1088,9 @@ static bool detect_link_and_local_sink(struct dc_link *link,
 		if (sink->edid_caps.panel_patch.skip_scdc_overwrite)
 			link->ctx->dc->debug.hdmi20_disable = true;
 
+		if (sink->edid_caps.panel_patch.remove_sink_ext_caps)
+			link->dpcd_sink_ext_caps.raw = 0;
+
 		if (dc_is_hdmi_signal(link->connector_signal))
 			read_scdc_caps(link->ddc, link->local_sink);
 
-- 
2.42.0