diff --git a/drivers/gpu/drm/amd/display/dc/link/protocols/link_dp_capability.c b/drivers/gpu/drm/amd/display/dc/link/protocols/link_dp_capability.c index 8f57b344f09e..766116ec627d 100644 --- a/drivers/gpu/drm/amd/display/dc/link/protocols/link_dp_capability.c +++ b/drivers/gpu/drm/amd/display/dc/link/protocols/link_dp_capability.c @@ -2062,7 +2062,7 @@ struct dc_link_settings dp_get_max_link_cap(struct dc_link *link) enum dc_link_rate lttpr_max_link_rate; enum dc_link_rate cable_max_link_rate; struct link_encoder *link_enc = NULL; - + bool is_uhbr13_5_supported = true; link_enc = link_enc_cfg_get_link_enc(link); ASSERT(link_enc); @@ -2083,6 +2083,9 @@ struct dc_link_settings dp_get_max_link_cap(struct dc_link *link) max_link_cap.link_spread = link->reported_link_cap.link_spread; + if (!link->dpcd_caps.dp_128b_132b_supported_link_rates.bits.UHBR13_5) + is_uhbr13_5_supported = false; + /* Lower link settings based on cable attributes * Cable ID is a DP2 feature to identify max certified link rate that * a cable can carry. The cable identification method requires both @@ -2101,9 +2104,13 @@ struct dc_link_settings dp_get_max_link_cap(struct dc_link *link) cable_max_link_rate = get_cable_max_link_rate(link); if (!link->dc->debug.ignore_cable_id && - cable_max_link_rate != LINK_RATE_UNKNOWN && - cable_max_link_rate < max_link_cap.link_rate) - max_link_cap.link_rate = cable_max_link_rate; + cable_max_link_rate != LINK_RATE_UNKNOWN) { + if (cable_max_link_rate < max_link_cap.link_rate) + max_link_cap.link_rate = cable_max_link_rate; + + if (!link->dpcd_caps.cable_id.bits.UHBR13_5_CAPABILITY) + is_uhbr13_5_supported = false; + } /* account for lttpr repeaters cap * notes: repeaters do not snoop in the DPRX Capabilities addresses (3.6.3). @@ -2116,12 +2123,19 @@ struct dc_link_settings dp_get_max_link_cap(struct dc_link *link) if (lttpr_max_link_rate < max_link_cap.link_rate) max_link_cap.link_rate = lttpr_max_link_rate; + if (!link->dpcd_caps.lttpr_caps.supported_128b_132b_rates.bits.UHBR13_5) + is_uhbr13_5_supported = false; + DC_LOG_HW_LINK_TRAINING("%s\n Training with LTTPR, max_lane count %d max_link rate %d \n", __func__, max_link_cap.lane_count, max_link_cap.link_rate); } + if (max_link_cap.link_rate == LINK_RATE_UHBR13_5 && + !is_uhbr13_5_supported) + max_link_cap.link_rate = LINK_RATE_UHBR10; + if (link_dp_get_encoding_format(&max_link_cap) == DP_128b_132b_ENCODING && link->dc->debug.disable_uhbr) max_link_cap.link_rate = LINK_RATE_HIGH3;