console: add same displaychangelistener registration pre-condition

Catch an invalid state. Mainly useful for documentation purposes.

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Message-id: 20170406120513.638-3-marcandre.lureau@redhat.com
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>

diff --git a/ui/console.c b/ui/console.c
index 0cbe5033dd636b480c7239e85377f3f94880730e..189eecfd294045b0db1713ce81db4bd91dd2710c 100644 (file)
--- a/ui/console.c
+++ b/ui/console.c
@@ -1410,6 +1410,8 @@ void register_displaychangelistener(DisplayChangeListener *dcl)
     static DisplaySurface *dummy;
     QemuConsole *con;
 
+    assert(!dcl->ds);
+
     if (dcl->ops->dpy_gl_ctx_create) {
         /* display has opengl support */
         assert(dcl->con);