Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Kuogee Hsieh <quic_khsieh@quicinc.com>,
        Stephen Boyd <swboyd@chromium.org>,
        Dmitry Baryshkov <dmitry.baryshkov@linaro.org>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 5.18 372/879] drm/msm/dp: do not stop transmitting phy test pattern during DP phy compliance test
Date:   Tue,  7 Jun 2022 18:58:10 +0200
Message-Id: <20220607165013.669857838@linuxfoundation.org>
In-Reply-To: <20220607165002.659942637@linuxfoundation.org>
References: <20220607165002.659942637@linuxfoundation.org>
User-Agent: quilt/0.66
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
Precedence: bulk

From: Kuogee Hsieh <quic_khsieh@quicinc.com>

[ Upstream commit 2788b4efa60c1e03ac10a156f3fdbd3be0f9198c ]

At normal operation, transmit phy test pattern has to be terminated before
DP controller switch to video ready state. However during phy compliance
testing, transmit phy test pattern should not be terminated until end of
compliance test which usually indicated by unplugged interrupt.

Only stop sending the train pattern in dp_ctrl_on_stream() if we're not
doing compliance testing. We also no longer reset 'p_level' and
'v_level' within dp_ctrl_on_link() due to both 'p_level' and 'v_level'
are acquired from link status at previous dpcd read and we like to use
those level to start link training.

Changes in v2:
-- add more details commit text
-- correct Fixes

Changes in v3:
-- drop unnecessary braces

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>
Patchwork: https://patchwork.freedesktop.org/patch/483564/
Link: https://lore.kernel.org/r/1650995939-28467-3-git-send-email-quic_khsieh@quicinc.com
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 | 14 ++++++--------
 1 file changed, 6 insertions(+), 8 deletions(-)

diff --git a/drivers/gpu/drm/msm/dp/dp_ctrl.c b/drivers/gpu/drm/msm/dp/dp_ctrl.c
index 193cc1a597ff..08cc48af03b7 100644
--- a/drivers/gpu/drm/msm/dp/dp_ctrl.c
+++ b/drivers/gpu/drm/msm/dp/dp_ctrl.c
@@ -1699,8 +1699,6 @@ int dp_ctrl_on_link(struct dp_ctrl *dp_ctrl)
 		ctrl->link->link_params.rate,
 		ctrl->link->link_params.num_lanes, ctrl->dp_ctrl.pixel_rate);
 
-	ctrl->link->phy_params.p_level = 0;
-	ctrl->link->phy_params.v_level = 0;
 
 	rc = dp_ctrl_enable_mainlink_clocks(ctrl);
 	if (rc)
@@ -1822,12 +1820,6 @@ int dp_ctrl_on_stream(struct dp_ctrl *dp_ctrl)
 		}
 	}
 
-	if (!dp_ctrl_channel_eq_ok(ctrl))
-		dp_ctrl_link_retrain(ctrl);
-
-	/* stop txing train pattern to end link training */
-	dp_ctrl_clear_training_pattern(ctrl);
-
 	ret = dp_ctrl_enable_stream_clocks(ctrl);
 	if (ret) {
 		DRM_ERROR("Failed to start pixel clocks. ret=%d\n", ret);
@@ -1839,6 +1831,12 @@ int dp_ctrl_on_stream(struct dp_ctrl *dp_ctrl)
 		return 0;
 	}
 
+	if (!dp_ctrl_channel_eq_ok(ctrl))
+		dp_ctrl_link_retrain(ctrl);
+
+	/* stop txing train pattern to end link training */
+	dp_ctrl_clear_training_pattern(ctrl);
+
 	/*
 	 * Set up transfer unit values and set controller state to send
 	 * video.
-- 
2.35.1