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From:   Kuogee Hsieh <khsieh@codeaurora.org>
To:     robdclark@gmail.com, sean@poorly.run, swboyd@chromium.org
Cc:     tanmay@codeaurora.org, abhinavk@codeaurora.org,
        aravindh@codeaurora.org, khsieh@codeaurora.org, airlied@linux.ie,
        daniel@ffwll.ch, linux-arm-msm@vger.kernel.org,
        dri-devel@lists.freedesktop.org, freedreno@lists.freedesktop.org,
        linux-kernel@vger.kernel.org
Subject: [PATCH] drm/msm/dp: fixes wrong connection state caused by failure of link train
Date:   Fri,  2 Oct 2020 15:09:19 -0700
Message-Id: <20201002220919.17245-1-khsieh@codeaurora.org>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

Connection state is set incorrectly happen at either failure of link train
or cable plugged in while suspended. This patch fixes these problems.
This patch also replace ST_SUSPEND_PENDING with ST_DISPLAY_OFF.

Signed-off-by: Kuogee Hsieh <khsieh@codeaurora.org>
---
 drivers/gpu/drm/msm/dp/dp_display.c | 52 ++++++++++++++---------------
 drivers/gpu/drm/msm/dp/dp_panel.c   |  5 +++
 2 files changed, 31 insertions(+), 26 deletions(-)

diff --git a/drivers/gpu/drm/msm/dp/dp_display.c b/drivers/gpu/drm/msm/dp/dp_display.c
index 431dff9de797..898c6cc1643a 100644
--- a/drivers/gpu/drm/msm/dp/dp_display.c
+++ b/drivers/gpu/drm/msm/dp/dp_display.c
@@ -45,7 +45,7 @@ enum {
 	ST_CONNECT_PENDING,
 	ST_CONNECTED,
 	ST_DISCONNECT_PENDING,
-	ST_SUSPEND_PENDING,
+	ST_DISPLAY_OFF,
 	ST_SUSPENDED,
 };
 
@@ -340,8 +340,6 @@ static int dp_display_process_hpd_high(struct dp_display_private *dp)
 	}
 
 	dp_add_event(dp, EV_USER_NOTIFICATION, true, 0);
-
-
 end:
 	return rc;
 }
@@ -489,7 +487,7 @@ static int dp_hpd_plug_handle(struct dp_display_private *dp, u32 data)
 	mutex_lock(&dp->event_mutex);
 
 	state =  atomic_read(&dp->hpd_state);
-	if (state == ST_SUSPEND_PENDING) {
+	if (state == ST_DISPLAY_OFF || state == ST_SUSPENDED) {
 		mutex_unlock(&dp->event_mutex);
 		return 0;
 	}
@@ -511,14 +509,14 @@ static int dp_hpd_plug_handle(struct dp_display_private *dp, u32 data)
 	hpd->hpd_high = 1;
 
 	ret = dp_display_usbpd_configure_cb(&dp->pdev->dev);
-	if (ret) {	/* failed */
+	if (ret) {	/* link train failed */
 		hpd->hpd_high = 0;
 		atomic_set(&dp->hpd_state, ST_DISCONNECTED);
+	} else {
+		/* start sentinel checking in case of missing uevent */
+		dp_add_event(dp, EV_CONNECT_PENDING_TIMEOUT, 0, tout);
 	}
 
-	/* start sanity checking */
-	dp_add_event(dp, EV_CONNECT_PENDING_TIMEOUT, 0, tout);
-
 	mutex_unlock(&dp->event_mutex);
 
 	/* uevent will complete connection part */
@@ -563,10 +561,6 @@ static int dp_hpd_unplug_handle(struct dp_display_private *dp, u32 data)
 	mutex_lock(&dp->event_mutex);
 
 	state = atomic_read(&dp->hpd_state);
-	if (state == ST_SUSPEND_PENDING) {
-		mutex_unlock(&dp->event_mutex);
-		return 0;
-	}
 
 	if (state == ST_DISCONNECT_PENDING || state == ST_DISCONNECTED) {
 		mutex_unlock(&dp->event_mutex);
@@ -594,7 +588,7 @@ static int dp_hpd_unplug_handle(struct dp_display_private *dp, u32 data)
 	 */
 	dp_display_usbpd_disconnect_cb(&dp->pdev->dev);
 
-	/* start sanity checking */
+	/* start sentinel checking in case of missing uevent */
 	dp_add_event(dp, EV_DISCONNECT_PENDING_TIMEOUT, 0, DP_TIMEOUT_5_SECOND);
 
 	/* signal the disconnect event early to ensure proper teardown */
@@ -634,7 +628,7 @@ static int dp_irq_hpd_handle(struct dp_display_private *dp, u32 data)
 
 	/* irq_hpd can happen at either connected or disconnected state */
 	state =  atomic_read(&dp->hpd_state);
-	if (state == ST_SUSPEND_PENDING) {
+	if (state == ST_DISPLAY_OFF) {
 		mutex_unlock(&dp->event_mutex);
 		return 0;
 	}
@@ -1067,7 +1061,7 @@ static irqreturn_t dp_display_irq_handler(int irq, void *dev_id)
 		}
 
 		if (hpd_isr_status & DP_DP_IRQ_HPD_INT_MASK) {
-			/* delete connect pending event first */
+			/* delete sentinel connect pending checking */
 			dp_del_event(dp, EV_CONNECT_PENDING_TIMEOUT);
 			dp_add_event(dp, EV_IRQ_HPD_INT, 0, 0);
 		}
@@ -1186,19 +1180,19 @@ static int dp_pm_resume(struct device *dev)
 
 	dp = container_of(dp_display, struct dp_display_private, dp_display);
 
+	/* start from dis connection state */
+	atomic_set(&dp->hpd_state, ST_DISCONNECTED);
+
 	dp_display_host_init(dp);
 
 	dp_catalog_ctrl_hpd_config(dp->catalog);
 
 	status = dp_catalog_hpd_get_state_status(dp->catalog);
 
-	if (status) {
+	if (status)
 		dp->dp_display.is_connected = true;
-	} else {
+	else
 		dp->dp_display.is_connected = false;
-		/* make sure next resume host_init be called */
-		dp->core_initialized = false;
-	}
 
 	return 0;
 }
@@ -1214,6 +1208,9 @@ static int dp_pm_suspend(struct device *dev)
 	if (dp_display->power_on == true)
 		dp_display_disable(dp, 0);
 
+	/* host_init will be called at pm_resume */
+	dp->core_initialized = false;
+
 	atomic_set(&dp->hpd_state, ST_SUSPENDED);
 
 	return 0;
@@ -1343,6 +1340,9 @@ int msm_dp_display_enable(struct msm_dp *dp, struct drm_encoder *encoder)
 
 	mutex_lock(&dp_display->event_mutex);
 
+	/* delete sentinel checking */
+	dp_del_event(dp_display, EV_CONNECT_PENDING_TIMEOUT);
+
 	rc = dp_display_set_mode(dp, &dp_display->dp_mode);
 	if (rc) {
 		DRM_ERROR("Failed to perform a mode set, rc=%d\n", rc);
@@ -1368,9 +1368,8 @@ int msm_dp_display_enable(struct msm_dp *dp, struct drm_encoder *encoder)
 		dp_display_unprepare(dp);
 	}
 
-	dp_del_event(dp_display, EV_CONNECT_PENDING_TIMEOUT);
-
-	if (state == ST_SUSPEND_PENDING)
+	/* manual kick off plug event to train link */
+	if (state == ST_DISPLAY_OFF)
 		dp_add_event(dp_display, EV_IRQ_HPD_INT, 0, 0);
 
 	/* completed connection */
@@ -1402,20 +1401,21 @@ int msm_dp_display_disable(struct msm_dp *dp, struct drm_encoder *encoder)
 
 	mutex_lock(&dp_display->event_mutex);
 
+	/* delete sentinel checking */
+	dp_del_event(dp_display, EV_DISCONNECT_PENDING_TIMEOUT);
+
 	dp_display_disable(dp_display, 0);
 
 	rc = dp_display_unprepare(dp);
 	if (rc)
 		DRM_ERROR("DP display unprepare failed, rc=%d\n", rc);
 
-	dp_del_event(dp_display, EV_DISCONNECT_PENDING_TIMEOUT);
-
 	state =  atomic_read(&dp_display->hpd_state);
 	if (state == ST_DISCONNECT_PENDING) {
 		/* completed disconnection */
 		atomic_set(&dp_display->hpd_state, ST_DISCONNECTED);
 	} else {
-		atomic_set(&dp_display->hpd_state, ST_SUSPEND_PENDING);
+		atomic_set(&dp_display->hpd_state, ST_DISPLAY_OFF);
 	}
 
 	mutex_unlock(&dp_display->event_mutex);
diff --git a/drivers/gpu/drm/msm/dp/dp_panel.c b/drivers/gpu/drm/msm/dp/dp_panel.c
index 18cec4fc5e0b..1b7a20dc2d8e 100644
--- a/drivers/gpu/drm/msm/dp/dp_panel.c
+++ b/drivers/gpu/drm/msm/dp/dp_panel.c
@@ -196,6 +196,11 @@ int dp_panel_read_sink_caps(struct dp_panel *dp_panel,
 					      &panel->aux->ddc);
 	if (!dp_panel->edid) {
 		DRM_ERROR("panel edid read failed\n");
+		/* check edid read fail is due to unplug */
+		if (!dp_catalog_hpd_get_state_status(panel->catalog)) {
+			rc = -ETIMEDOUT;
+			goto end;
+		}
 
 		/* fail safe edid */
 		mutex_lock(&connector->dev->mode_config.mutex);

base-commit: 6fa6fd6a3e2cb76f7d54220daa1266a94c13bc4d
-- 
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