From: Wesley Chalmers Date: Wed, 24 Mar 2021 19:03:21 +0000 (-0400) Subject: drm/amd/display: Set LTTPR Transparent Mode after read link cap X-Git-Tag: accepted/tizen/unified/20230118.172025~6864^2~10^2~20 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=ac62875e9b6bfd3c8be91501dbb71ee8cbe1ce84;p=platform%2Fkernel%2Flinux-rpi.git drm/amd/display: Set LTTPR Transparent Mode after read link cap [WHY] SCR for DP 2.0 Spec states that a DPTX shall put LTTPRs into Transparent mode after reading LTTPR Capability registers on HPD. The wording of the SCR is somewhat ambiguous as to whether Transparent mode must be set explicity, or is implicitly set on LTTPR capability read. Explicitly setting Transparent mode after LTTPR capability read should cover all cases. Signed-off-by: Wesley Chalmers Reviewed-by: Jun Lei Acked-by: Anson Jacob Tested-by: Daniel Wheeler Signed-off-by: Alex Deucher --- 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 38fabaf..586f05a 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 @@ -3705,9 +3705,10 @@ bool dp_retrieve_lttpr_cap(struct dc_link *link) 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); - if (is_lttpr_present) + if (is_lttpr_present) { CONN_DATA_DETECT(link, lttpr_dpcd_data, sizeof(lttpr_dpcd_data), "LTTPR Caps: "); - else + configure_lttpr_mode_transparent(link); + } else link->lttpr_mode = LTTPR_MODE_NON_LTTPR; } return is_lttpr_present;