Commit 3471b9a3 authored Sep 24, 2025 by Relja Vojvodic Committed by Alex Deucher Oct 20, 2025

drm/amd/display: Rework HDMI data channel reads



Fix the HDMI data channel reads to respect scdc_present field
to pass compliance test.

Reviewed-by: Wenjing Liu <wenjing.liu@amd.com>
Signed-off-by: Relja Vojvodic <rvojvodi@amd.com>
Signed-off-by: Aurabindo Pillai <aurabindo.pillai@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

parent f7124dd5

drivers/gpu/drm/amd/display/dc/dc_types.h

+1 −0

Original line number	Diff line number	Diff line
		@@ -212,6 +212,7 @@ struct dc_edid_caps {
		bool edid_hdmi;
		bool hdr_supported;
		bool rr_capable;
		bool scdc_present;

		struct dc_panel_patch panel_patch;
		};

drivers/gpu/drm/amd/display/dc/link/link_detection.c

+4 −0

Original line number	Diff line number	Diff line
		@@ -270,6 +270,10 @@ static void read_scdc_caps(struct ddc_service *ddc_service,
		uint8_t slave_address = HDMI_SCDC_ADDRESS;
		uint8_t offset = HDMI_SCDC_MANUFACTURER_OUI;

		if (ddc_service->link->local_sink &&
		!ddc_service->link->local_sink->edid_caps.scdc_present)
		return;

		link_query_ddc_data(ddc_service, slave_address, &offset,
		sizeof(offset), sink->scdc_caps.manufacturer_OUI.byte,
		sizeof(sink->scdc_caps.manufacturer_OUI.byte));

drivers/gpu/drm/amd/display/dc/link/protocols/link_ddc.c

+2 −1

Original line number	Diff line number	Diff line
		@@ -549,7 +549,8 @@ void write_scdc_data(struct ddc_service *ddc_service,
		/Lower than 340 Scramble bit from SCDC caps/

		if (ddc_service->link->local_sink &&
		ddc_service->link->local_sink->edid_caps.panel_patch.skip_scdc_overwrite)
		(ddc_service->link->local_sink->edid_caps.panel_patch.skip_scdc_overwrite \|\|
		!ddc_service->link->local_sink->edid_caps.scdc_present))
		return;

		link_query_ddc_data(ddc_service, slave_address, &offset,