drm/amd/display: DispalyPort: Write OUI only if panel supports it (933fe2cb) · Commits · 戴 / test

[why] Organizational Unit Identifier register is optional, and its presence is published via Down Stream Port Count register. Writing this register when not available will result in errors [how] Read this register and continue writing OUI only if the panel has the support advertised. Signed-off-by:

Aurabindo Pillai <aurabindo.pillai@amd.com> Reviewed-by:

Aric Cyr <Aric.Cyr@amd.com> Acked-by:

Rodrigo Siqueira <Rodrigo.Siqueira@amd.com> Signed-off-by:

Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/display/dc/core/dc_link_dp.c

+15 −0

Original line number	Diff line number	Diff line
		@@ -4227,6 +4227,21 @@ void dp_set_fec_enable(struct dc_link *link, bool enable)
		void dpcd_set_source_specific_data(struct dc_link *link)
		{
		const uint32_t post_oui_delay = 30; // 30ms
		uint8_t dspc = 0;
		enum dc_status ret = DC_ERROR_UNEXPECTED;

		ret = core_link_read_dpcd(link, DP_DOWN_STREAM_PORT_COUNT, &dspc,
		sizeof(dspc));

		if (ret != DC_OK) {
		DC_LOG_ERROR("Error in DP aux read transaction,"
		" not writing source specific data\n");
		return;
		}

		/* Return if OUI unsupported */
		if (!(dspc & DP_OUI_SUPPORT))
		return;

		if (!link->dc->vendor_signature.is_valid) {
		struct dpcd_amd_signature amd_signature;

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