From ac62875e9b6bfd3c8be91501dbb71ee8cbe1ce84 Mon Sep 17 00:00:00 2001 From: Wesley Chalmers Date: Wed, 24 Mar 2021 15:03:21 -0400 Subject: [PATCH] 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 --- drivers/gpu/drm/amd/display/dc/core/dc_link_dp.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) 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 38fabaff51ea..586f05a6cd77 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; -- 2.25.1