Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
From:   Kuogee Hsieh <quic_khsieh@quicinc.com>
To:     <dri-devel@lists.freedesktop.org>, <robdclark@gmail.com>,
        <sean@poorly.run>, <swboyd@chromium.org>, <vkoul@kernel.org>,
        <daniel@ffwll.ch>, <airlied@linux.ie>, <agross@kernel.org>,
        <dmitry.baryshkov@linaro.org>, <bjorn.andersson@linaro.org>
CC:     Kuogee Hsieh <quic_khsieh@quicinc.com>,
        <quic_abhinavk@quicinc.com>, <aravindh@codeaurora.org>,
        <quic_sbillaka@quicinc.com>, <freedreno@lists.freedesktop.org>,
        <linux-arm-msm@vger.kernel.org>, <linux-kernel@vger.kernel.org>
Subject: [PATCH v15 4/4] drm/msm/dp: stop link training after link training 2 failed
Date:   Fri, 14 Jan 2022 13:11:50 -0800
Message-ID: <1642194710-2512-5-git-send-email-quic_khsieh@quicinc.com>
In-Reply-To: <1642194710-2512-1-git-send-email-quic_khsieh@quicinc.com>
References: <1642194710-2512-1-git-send-email-quic_khsieh@quicinc.com>
MIME-Version: 1.0
Content-Type: text/plain
Precedence: bulk

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>
---
 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 f98df93..245e1b9 100644
--- a/drivers/gpu/drm/msm/dp/dp_ctrl.c
+++ b/drivers/gpu/drm/msm/dp/dp_ctrl.c
@@ -1755,6 +1755,9 @@ 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);
 		}
 	}
 
-- 
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project