[v2] drm/msm/dp: fixes wrong connection state caused by failure of link train

diff --git a/drivers/gpu/drm/msm/dp/dp_display.c b/drivers/gpu/drm/msm/dp/dp_display.c
index fd16e12ab2f8..2372de2865e6 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,
 };
 
@@ -489,7 +489,7 @@  static int dp_hpd_plug_handle(struct dp_display_private *dp, u32 data)
 	mutex_lock(&dp->event_mutex);
 
 	state =  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 +511,14 @@  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;
 		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 */
@@ -563,11 +563,6 @@  static int dp_hpd_unplug_handle(struct dp_display_private *dp, u32 data)
 	mutex_lock(&dp->event_mutex);
 
 	state = 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);
 		return 0;
@@ -594,7 +589,7 @@  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 +629,7 @@  static int dp_irq_hpd_handle(struct dp_display_private *dp, u32 data)
 
 	/* irq_hpd can happen at either connected or disconnected state */
 	state =  dp->hpd_state;
-	if (state == ST_SUSPEND_PENDING) {
+	if (state == ST_DISPLAY_OFF) {
 		mutex_unlock(&dp->event_mutex);
 		return 0;
 	}
@@ -1067,7 +1062,7 @@  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 */
+			/* stop sentinel connect pending checking */
 			dp_del_event(dp, EV_CONNECT_PENDING_TIMEOUT);
 			dp_add_event(dp, EV_IRQ_HPD_INT, 0, 0);
 		}
@@ -1188,19 +1183,19 @@  static int dp_pm_resume(struct device *dev)
 
 	mutex_lock(&dp->event_mutex);
 
+	/* start from disconnected state */
+	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;
-	}
 
 	mutex_unlock(&dp->event_mutex);
 
@@ -1222,6 +1217,9 @@  static int dp_pm_suspend(struct device *dev)
 
 	dp->hpd_state = ST_SUSPENDED;
 
+	/* host_init will be called at pm_resume */
+	dp->core_initialized = false;
+
 	mutex_unlock(&dp->event_mutex);
 
 	return 0;
@@ -1351,6 +1349,7 @@  int msm_dp_display_enable(struct msm_dp *dp, struct drm_encoder *encoder)
 
 	mutex_lock(&dp_display->event_mutex);
 
+	/* stop sentinel checking */
 	dp_del_event(dp_display, EV_CONNECT_PENDING_TIMEOUT);
 
 	rc = dp_display_set_mode(dp, &dp_display->dp_mode);
@@ -1378,7 +1377,8 @@  int msm_dp_display_enable(struct msm_dp *dp, struct drm_encoder *encoder)
 		dp_display_unprepare(dp);
 	}
 
-	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 */
@@ -1410,6 +1410,7 @@  int msm_dp_display_disable(struct msm_dp *dp, struct drm_encoder *encoder)
 
 	mutex_lock(&dp_display->event_mutex);
 
+	/* stop sentinel checking */
 	dp_del_event(dp_display, EV_DISCONNECT_PENDING_TIMEOUT);
 
 	dp_display_disable(dp_display, 0);
@@ -1423,7 +1424,7 @@  int msm_dp_display_disable(struct msm_dp *dp, struct drm_encoder *encoder)
 		/* completed disconnection */
 		dp_display->hpd_state = ST_DISCONNECTED;
 	} else {
-		dp_display->hpd_state = ST_SUSPEND_PENDING;
+		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);