drm/udl: Sync pending URBs at the end of suspend

It's better to perform the sync at the very last of the suspend
instead of the pipe-disable function, so that we can catch all pending
URBs (if any).

While we're at it, drop the error code from udl_sync_pending_urb()
since we basically ignore it; instead, give a clear error message
indicating a problem.
Acked-by: Thomas Zimmermann <tzimmermann@suse.de>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Link: https://patchwork.freedesktop.org/patch/msgid/20220908095115.23396-13-tiwai@suse.de

drivers/gpu/drm/udl/udl_drv.c

@@ -21,8 +21,14 @@ static int udl_usb_suspend(struct usb_interface *interface,
 			   pm_message_t message)
 {
 	struct drm_device *dev = usb_get_intfdata(interface);
+	int ret;
 
-	return drm_mode_config_helper_suspend(dev);
+	ret = drm_mode_config_helper_suspend(dev);
+	if (ret)
+		return ret;
+
+	udl_sync_pending_urbs(dev);
+	return 0;
 }
 
 static int udl_usb_resume(struct usb_interface *interface)

drivers/gpu/drm/udl/udl_drv.h

@@ -77,7 +77,7 @@ struct drm_connector *udl_connector_init(struct drm_device *dev);
 struct urb *udl_get_urb(struct drm_device *dev);
 
 int udl_submit_urb(struct drm_device *dev, struct urb *urb, size_t len);
-int udl_sync_pending_urbs(struct drm_device *dev);
+void udl_sync_pending_urbs(struct drm_device *dev);
 void udl_urb_completion(struct urb *urb);
 
 int udl_init(struct udl_device *udl);

drivers/gpu/drm/udl/udl_main.c

@@ -290,10 +290,9 @@ int udl_submit_urb(struct drm_device *dev, struct urb *urb, size_t len)
 }
 
 /* wait until all pending URBs have been processed */
-int udl_sync_pending_urbs(struct drm_device *dev)
+void udl_sync_pending_urbs(struct drm_device *dev)
 {
 	struct udl_device *udl = to_udl(dev);
-	int ret = 0;
 
 	spin_lock_irq(&udl->urbs.lock);
 	/* 2 seconds as a sane timeout */
@@ -301,9 +300,8 @@ int udl_sync_pending_urbs(struct drm_device *dev)
 					 udl->urbs.available == udl->urbs.count,
 					 udl->urbs.lock,
 					 msecs_to_jiffies(2000)))
-		ret = -ETIMEDOUT;
+		drm_err(dev, "Timeout for syncing pending URBs\n");
 	spin_unlock_irq(&udl->urbs.lock);
-	return ret;
 }
 
 int udl_init(struct udl_device *udl)

drivers/gpu/drm/udl/udl_modeset.c

@@ -377,8 +377,6 @@ udl_simple_display_pipe_disable(struct drm_simple_display_pipe *pipe)
 	buf = udl_dummy_render(buf);
 
 	udl_submit_urb(dev, urb, buf - (char *)urb->transfer_buffer);
-
-	udl_sync_pending_urbs(dev);
 }
 
 static void