From: Michael Strauss Date: Tue, 21 May 2024 18:52:37 +0000 (-0400) Subject: drm/amd/display: Add fallback defaults for invalid LTTPR DPCD caps X-Git-Tag: v6.11-rc1~141^2~18^2~108 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=82c421ba46ecd11b67e15a86ad382ab8a6ed1d5d;p=thirdparty%2Fkernel%2Flinux.git drm/amd/display: Add fallback defaults for invalid LTTPR DPCD caps [WHY] Some sinks are observed to return invalid LTTPR revision and/or invalid LTTPR link rate capabilities. [HOW] Assume any LTTPR which reports invalid max link rate supports HBR3. Don't validate LTTPR DPCD revision in dp_is_lttpr_present check. Reviewed-by: George Shen Reviewed-by: Wenjing Liu Acked-by: Zaeem Mohamed Signed-off-by: Michael Strauss Tested-by: Daniel Wheeler Signed-off-by: Alex Deucher --- 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 964abccebdc64..1ff9876e3ca37 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 @@ -363,10 +363,10 @@ bool dp_is_128b_132b_signal(struct pipe_ctx *pipe_ctx) bool dp_is_lttpr_present(struct dc_link *link) { + /* Some sink devices report invalid LTTPR revision, so don't validate against that cap */ return (dp_parse_lttpr_repeater_count(link->dpcd_caps.lttpr_caps.phy_repeater_cnt) != 0 && link->dpcd_caps.lttpr_caps.max_lane_count > 0 && - link->dpcd_caps.lttpr_caps.max_lane_count <= 4 && - link->dpcd_caps.lttpr_caps.revision.raw >= 0x14); + link->dpcd_caps.lttpr_caps.max_lane_count <= 4); } /* in DP compliance test, DPR-120 may have @@ -399,7 +399,20 @@ static enum dc_link_rate get_link_rate_from_max_link_bw( static enum dc_link_rate get_lttpr_max_link_rate(struct dc_link *link) { - enum dc_link_rate lttpr_max_link_rate = link->dpcd_caps.lttpr_caps.max_link_rate; + + enum dc_link_rate lttpr_max_link_rate = LINK_RATE_UNKNOWN; + + switch (link->dpcd_caps.lttpr_caps.max_link_rate) { + case LINK_RATE_LOW: + case LINK_RATE_HIGH: + case LINK_RATE_HIGH2: + case LINK_RATE_HIGH3: + lttpr_max_link_rate = link->dpcd_caps.lttpr_caps.max_link_rate; + break; + default: + // Assume all LTTPRs support up to HBR3 to improve misbehaving sink interop + lttpr_max_link_rate = LINK_RATE_HIGH3; + } if (link->dpcd_caps.lttpr_caps.supported_128b_132b_rates.bits.UHBR20) lttpr_max_link_rate = LINK_RATE_UHBR20;