From: Kuogee Hsieh quic_khsieh@quicinc.com
[ Upstream commit 9051d629dbf7a998a40f7eac65a9512b01bc3bb8 ]
Each DP link training contains link training 1 followed by link training 2. There is maximum of 5 retries of DP link training before declared link training failed. It is required to stop link training at end of link training 2 if it is failed so that next link training 1 can start freshly. This patch fixes link compliance test case 4.3.1.13 (Source Device Link Training EQ Fallback Test).
Changes in v10: -- group into one series
Changes in v11: -- drop drm/msm/dp: dp_link_parse_sink_count() return immediately if aux read
Fixes: 2e0adc765d88 ("drm/msm/dp: do not end dp link training until video is ready") Signed-off-by: Kuogee Hsieh quic_khsieh@quicinc.com Reviewed-by: Stephen Boyd swboyd@chromium.org Link: https://lore.kernel.org/r/1642531648-8448-5-git-send-email-quic_khsieh@quici... Signed-off-by: Dmitry Baryshkov dmitry.baryshkov@linaro.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/gpu/drm/msm/dp/dp_ctrl.c | 3 +++ 1 file changed, 3 insertions(+)
diff --git a/drivers/gpu/drm/msm/dp/dp_ctrl.c b/drivers/gpu/drm/msm/dp/dp_ctrl.c index 9c80b493f974..8d1ea694d06c 100644 --- a/drivers/gpu/drm/msm/dp/dp_ctrl.c +++ b/drivers/gpu/drm/msm/dp/dp_ctrl.c @@ -1748,6 +1748,9 @@ int dp_ctrl_on_link(struct dp_ctrl *dp_ctrl) /* end with failure */ break; /* lane == 1 already */ } + + /* stop link training before start re training */ + dp_ctrl_clear_training_pattern(ctrl); } }