From ca7a1ced44ec3fe5742571e57c6a55a6483bdda3 Mon Sep 17 00:00:00 2001
From: Sung Joon Kim <sungkim@amd.com>
Date: Sun, 23 Jan 2022 13:20:11 -0500
Subject: drm/amd/display: remove PHY repeater count check for LTTPR mode
Git-commit: 72b90723b3760c69721b04f59436f38cd215e2df
Patch-mainline: v5.18-rc1
References: jsc#PED-1166 jsc#PED-1168 jsc#PED-1170 jsc#PED-1218 jsc#PED-1220 jsc#PED-1222 jsc#PED-1223 jsc#PED-1225
[why]
Due to bad hardware, the PHY repeater count in LTTPR cap is read as 0xFF
in some monitors while the LTTPR is actually present.
[how]
Remove PHY repeater counter check when configuring LTTPR mode.
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Reviewed-by: Jun Lei <Jun.Lei@amd.com>
Acked-by: Rodrigo Siqueira <Rodrigo.Siqueira@amd.com>
Signed-off-by: Sung Joon Kim <sungkim@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Acked-by: Patrik Jakobsson <pjakobsson@suse.de>
---
drivers/gpu/drm/amd/display/dc/core/dc_link_dp.c | 3 +--
1 file changed, 1 insertion(+), 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 4e28a8ea6fe3..aced123dcdac 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
@@ -5069,9 +5069,8 @@ bool dp_retrieve_lttpr_cap(struct dc_link *link)
DP_LT_TUNABLE_PHY_REPEATER_FIELD_DATA_STRUCTURE_REV];
/* Attempt to train in LTTPR transparent mode if repeater count exceeds 8. */
- is_lttpr_present = (dp_convert_to_count(link->dpcd_caps.lttpr_caps.phy_repeater_cnt) != 0 &&
+ is_lttpr_present = (link->dpcd_caps.lttpr_caps.max_lane_count > 0 &&
link->dpcd_caps.lttpr_caps.phy_repeater_cnt < 0xff &&
- 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) {
--
2.38.1