disp: msm: dp: exit stream enable on cable disconnect

Exit stream enable on cable disconnect considering that the
controller and display modules would have transitioned to aborted
state. It is possible that the disconnect might have prevented
the link clock from being enabled, so we have to skip any register
programming in the link clock domain. We remove the unprepare
call from the DRM wrapper error handling since that path can lead
to unclocked register access when the link clock is not enabled.

Change-Id: I92595c0824193df63c2746bc8cd644f59c33604a
Signed-off-by: Tatenda Chipeperekwa <[email protected]>

msm/dp/dp_ctrl.c

@@ -1168,6 +1168,11 @@ static int dp_ctrl_stream_on(struct dp_ctrl *dp_ctrl, struct dp_panel *panel)
 
 	ctrl = container_of(dp_ctrl, struct dp_ctrl_private, dp_ctrl);
 
+	if (!ctrl->power_on) {
+		DP_DEBUG("controller powered off\n");
+		return -EPERM;
+	}
+
 	rc = dp_ctrl_enable_stream_clocks(ctrl, panel);
 	if (rc) {
 		DP_ERR("failure on stream clock enable\n");

msm/dp/dp_display.c

@@ -1948,8 +1948,8 @@ static int dp_display_prepare(struct dp_display *dp_display, void *panel)
 end:
 	mutex_unlock(&dp->session_lock);
 
-	SDE_EVT32_EXTERNAL(SDE_EVTLOG_FUNC_EXIT, dp->state);
-	return 0;
+	SDE_EVT32_EXTERNAL(SDE_EVTLOG_FUNC_EXIT, dp->state, rc);
+	return rc;
 }
 
 static int dp_display_set_stream_info(struct dp_display *dp_display,
@@ -2061,7 +2061,7 @@ static int dp_display_enable(struct dp_display *dp_display, void *panel)
 	dp_display_state_add(DP_STATE_ENABLED);
 end:
 	mutex_unlock(&dp->session_lock);
-	SDE_EVT32_EXTERNAL(SDE_EVTLOG_FUNC_EXIT, dp->state);
+	SDE_EVT32_EXTERNAL(SDE_EVTLOG_FUNC_EXIT, dp->state, rc);
 	return rc;
 }
 

msm/dp/dp_drm.c

@@ -116,11 +116,9 @@ static void dp_bridge_pre_enable(struct drm_bridge *drm_bridge)
 	dp->set_stream_info(dp, bridge->dp_panel, 0, 0, 0, 0, 0);
 
 	rc = dp->enable(dp, bridge->dp_panel);
-	if (rc) {
+	if (rc)
 		DP_ERR("[%d] DP display enable failed, rc=%d\n",
 		       bridge->id, rc);
-		dp->unprepare(dp, bridge->dp_panel);
-	}
 }
 
 static void dp_bridge_enable(struct drm_bridge *drm_bridge)