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drm/amd/display: DispalyPort: Write OUI only if panel supports it

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[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>
This commit is contained in:
Aurabindo Pillai 2020-04-07 10:22:27 -04:00 committed by Alex Deucher
parent e32b2484b3
commit 933fe2cbf2
1 changed files with 15 additions and 0 deletions
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15
drivers/gpu/drm/amd/display/dc/core/dc_link_dp.c
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@ -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;