From 967727021e75f6c1d9972d5a87f759155f935d75 Mon Sep 17 00:00:00 2001 From: Aurabindo Pillai Date: Tue, 7 Apr 2020 10:22:27 -0400 Subject: [PATCH] drm/amd/display: DispalyPort: Write OUI only if panel supports it [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 Reviewed-by: Aric Cyr Acked-by: Rodrigo Siqueira Signed-off-by: Alex Deucher --- drivers/gpu/drm/amd/display/dc/core/dc_link_dp.c | 15 +++++++++++++++ 1 file changed, 15 insertions(+) diff --git a/drivers/gpu/drm/amd/display/dc/core/dc_link_dp.c b/drivers/gpu/drm/amd/display/dc/core/dc_link_dp.c index 3408c36ace48..5d2ae2fb7e45 100644 --- a/drivers/gpu/drm/amd/display/dc/core/dc_link_dp.c +++ b/drivers/gpu/drm/amd/display/dc/core/dc_link_dp.c @@ -4218,6 +4218,21 @@ 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; -- 2.11.0