disp: msm: sde: ignore HW recovery disable event

The current SDE driver logic during MDP hang cases is to send a capture
event to user-mode if recovery custom event is registered. Otherwise, it
will enforce a device panic for debugging purpose. This might have a race
condition during the display tear-down sequence as user-mode unregisters
the recovery event when the last frame is in progress. If the last frame
causes any MDP hang, it will result in a device reset. Support only the
event registration to avoid this case, since HW recovery is not expected
to be changed dynamically.

Change-Id: I8a11e1060b239ac6827f1d078e3e396cff4c1325
Signed-off-by: Veera Sundaram Sankaran <[email protected]>

msm/sde/sde_connector.c

@@ -2994,8 +2994,7 @@ error_free_conn:
 	return ERR_PTR(rc);
 }
 
-static int _sde_conn_hw_recovery_handler(
-		struct drm_connector *connector, bool val)
+static int _sde_conn_enable_hw_recovery(struct drm_connector *connector)
 {
 	struct sde_connector *c_conn;
 
@@ -3006,7 +3005,7 @@ static int _sde_conn_hw_recovery_handler(
 	c_conn = to_sde_connector(connector);
 
 	if (c_conn->encoder)
-		sde_encoder_recovery_events_handler(c_conn->encoder, val);
+		sde_encoder_enable_recovery_event(c_conn->encoder);
 
 	return 0;
 }
@@ -3024,7 +3023,7 @@ int sde_connector_register_custom_event(struct sde_kms *kms,
 		ret = 0;
 		break;
 	case DRM_EVENT_SDE_HW_RECOVERY:
-		ret = _sde_conn_hw_recovery_handler(conn_drm, val);
+		ret = _sde_conn_enable_hw_recovery(conn_drm);
 		break;
 	default:
 		break;

msm/sde/sde_encoder.c

@@ -5422,8 +5422,7 @@ bool sde_encoder_recovery_events_enabled(struct drm_encoder *encoder)
 	return sde_enc->recovery_events_enabled;
 }
 
-void sde_encoder_recovery_events_handler(struct drm_encoder *encoder,
-		bool enabled)
+void sde_encoder_enable_recovery_event(struct drm_encoder *encoder)
 {
 	struct sde_encoder_virt *sde_enc;
 
@@ -5433,5 +5432,5 @@ void sde_encoder_recovery_events_handler(struct drm_encoder *encoder,
 	}
 
 	sde_enc = to_sde_encoder_virt(encoder);
-	sde_enc->recovery_events_enabled = enabled;
+	sde_enc->recovery_events_enabled = true;
 }

msm/sde/sde_encoder.h

@@ -486,12 +486,11 @@ int sde_encoder_display_failure_notification(struct drm_encoder *enc,
 bool sde_encoder_recovery_events_enabled(struct drm_encoder *encoder);
 
 /**
- * sde_encoder_recovery_events_handler - handler to enable/disable the
- * sw recovery for this connector
+ * sde_encoder_enable_recovery_event - handler to enable the sw recovery
+ * for this connector
  * @drm_enc:    Pointer to drm encoder structure
  */
-void sde_encoder_recovery_events_handler(struct drm_encoder *encoder,
-		bool val);
+void sde_encoder_enable_recovery_event(struct drm_encoder *encoder);
 /**
  * sde_encoder_in_clone_mode - checks if underlying phys encoder is in clone
  *	mode or independent display mode. ref@ WB in Concurrent writeback mode.