drm/msm: Re-order uninit function to work during probe defer

If bind fails, we can call msm_drm_uninit before kms elements have been
created. In this case, drm_atomic_helper_shutdown will fail since there
are no drm objects. Only call drm unregistration and shutdown if drm is
registered.

Also while we're in here move the workqueue destruction to below
component_unbind since components could be actively using the wq during
uninit or in their unbind routine.
Reviewed-by: NRob Clark <robdclark@chromium.org>
Signed-off-by: NSean Paul <seanpaul@chromium.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20190524202919.179289-1-sean@poorly.run

drivers/gpu/drm/msm/msm_drv.c

@@ -259,13 +259,24 @@ static int msm_drm_uninit(struct device *dev)
 	struct msm_mdss *mdss = priv->mdss;
 	int i;
 
+	/*
+	 * Shutdown the hw if we're far enough along where things might be on.
+	 * If we run this too early, we'll end up panicking in any variety of
+	 * places. Since we don't register the drm device until late in
+	 * msm_drm_init, drm_dev->registered is used as an indicator that the
+	 * shutdown will be successful.
+	 */
+	if (ddev->registered) {
+		drm_dev_unregister(ddev);
+		drm_atomic_helper_shutdown(ddev);
+	}
+
 	/* We must cancel and cleanup any pending vblank enable/disable
 	 * work before drm_irq_uninstall() to avoid work re-enabling an
 	 * irq after uninstall has disabled it.
 	 */
 
 	flush_workqueue(priv->wq);
-	destroy_workqueue(priv->wq);
 
 	/* clean up event worker threads */
 	for (i = 0; i < priv->num_crtcs; i++) {
@@ -279,8 +290,6 @@ static int msm_drm_uninit(struct device *dev)
 
 	drm_kms_helper_poll_fini(ddev);
 
-	drm_dev_unregister(ddev);
-
 	msm_perf_debugfs_cleanup(priv);
 	msm_rd_debugfs_cleanup(priv);
 
@@ -288,7 +297,7 @@ static int msm_drm_uninit(struct device *dev)
 	if (fbdev && priv->fbdev)
 		msm_fbdev_free(ddev);
 #endif
-	drm_atomic_helper_shutdown(ddev);
+
 	drm_mode_config_cleanup(ddev);
 
 	pm_runtime_get_sync(dev);
@@ -313,6 +322,7 @@ static int msm_drm_uninit(struct device *dev)
 	ddev->dev_private = NULL;
 	drm_dev_put(ddev);
 
+	destroy_workqueue(priv->wq);
 	kfree(priv);
 
 	return 0;