diff --git a/hw/xwayland/xwayland-window.c b/hw/xwayland/xwayland-window.c
index a4f02a058..92ec4995c 100644
--- a/hw/xwayland/xwayland-window.c
+++ b/hw/xwayland/xwayland-window.c
@@ -569,6 +569,29 @@ xwl_window_set_fullscreen(struct xwl_window *xwl_window)
     return TRUE;
 }
 
+void
+xwl_window_rootful_update_fullscreen(struct xwl_window *xwl_window,
+                                     struct xwl_output *xwl_output)
+{
+    struct xwl_screen *xwl_screen = xwl_window->xwl_screen;
+
+    if (!xwl_screen->fullscreen)
+        return;
+
+    if (xwl_window->window != xwl_screen->screen->root)
+        return;
+
+    if (xwl_window->wl_output_fullscreen != xwl_output->output)
+        return;
+
+    /* The size and position of the output may have changed, clear our
+     * output to make sure the next call to xwl_window_set_fullscreen()
+     * recomputes the size and updates the viewport as needed.
+     */
+    xwl_window->wl_output_fullscreen = NULL;
+    xwl_window_set_fullscreen(xwl_window);
+}
+
 void
 xwl_window_rootful_update_title(struct xwl_window *xwl_window)
 {
diff --git a/hw/xwayland/xwayland-window.h b/hw/xwayland/xwayland-window.h
index 45ae16da0..7fbb2a623 100644
--- a/hw/xwayland/xwayland-window.h
+++ b/hw/xwayland/xwayland-window.h
@@ -135,7 +135,8 @@ Bool xwl_window_has_viewport_enabled(struct xwl_window *xwl_window);
 Bool xwl_window_is_toplevel(WindowPtr window);
 void xwl_window_check_resolution_change_emulation(struct xwl_window *xwl_window);
 void xwl_window_rootful_update_title(struct xwl_window *xwl_window);
-
+void xwl_window_rootful_update_fullscreen(struct xwl_window *xwl_window,
+                                          struct xwl_output *xwl_output);
 void xwl_window_set_window_pixmap(WindowPtr window, PixmapPtr pixmap);
 
 Bool xwl_realize_window(WindowPtr window);