From: Aurabindo Pillai <aurabindo.pillai@xxxxxxx>
[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@xxxxxxx>
Reviewed-by: Aric Cyr <Aric.Cyr@xxxxxxx>
Acked-by: Rodrigo Siqueira <Rodrigo.Siqueira@xxxxxxx>
---
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;
--
2.26.0
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