[PATCH 14/24] drm/amd/display: Set LTTPR Transparent Mode after read link cap

[Anson Jacob]

From: Wesley Chalmers <Wesley.Chalmers at amd.com>

[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 <Wesley.Chalmers at amd.com>
Reviewed-by: Jun Lei <Jun.Lei at amd.com>
Acked-by: Anson Jacob <Anson.Jacob at amd.com>
---
 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