[PATCH] drm/msm/dp: reset the link phy params before link training

From: Abhinav Kumar
Date: Thu Jul 25 2024 - 18:30:20 EST


Before re-starting link training reset the link phy params namely
the pre-emphasis and voltage swing levels otherwise the next
link training begins at the previously cached levels which can result
in link training failures.

Fixes: 8ede2ecc3e5e ("drm/msm/dp: Add DP compliance tests on Snapdragon Chipsets")
Signed-off-by: Abhinav Kumar <quic_abhinavk@xxxxxxxxxxx>
---
drivers/gpu/drm/msm/dp/dp_ctrl.c | 2 ++
1 file changed, 2 insertions(+)

diff --git a/drivers/gpu/drm/msm/dp/dp_ctrl.c b/drivers/gpu/drm/msm/dp/dp_ctrl.c
index cdfcb54a3618..c7a89ab21e09 100644
--- a/drivers/gpu/drm/msm/dp/dp_ctrl.c
+++ b/drivers/gpu/drm/msm/dp/dp_ctrl.c
@@ -1286,6 +1286,8 @@ static int dp_ctrl_link_train(struct dp_ctrl_private *ctrl,
link_info.rate = ctrl->link->link_params.rate;
link_info.capabilities = DP_LINK_CAP_ENHANCED_FRAMING;

+ dp_link_reset_phy_params_vx_px(ctrl->link);
+
dp_aux_link_configure(ctrl->aux, &link_info);

if (drm_dp_max_downspread(dpcd))
--
2.44.0