Index: darkplaces/vid_glx.c
diff -u darkplaces/vid_glx.c:1.72 darkplaces/vid_glx.c:1.73
--- darkplaces/vid_glx.c:1.72	Fri Feb  4 02:29:02 2005
+++ darkplaces/vid_glx.c	Fri Feb  4 04:15:10 2005
@@ -619,7 +619,8 @@
 	if (vid_usingvsync != vid_usevsync && gl_videosyncavailable)
 	{
 		vid_usingvsync = vid_usevsync;
-		qglXSwapIntervalSGI (vid_usevsync);
+		if (qglXSwapIntervalSGI (vid_usevsync))
+			Con_Print("glXSwapIntervalSGI didn't accept the vid_vsync change, it will take effect on next vid_restart (GLX_SGI_swap_control does not allow turning off vsync)\n");
 	}
 
 // handle the mouse state when windowed if that's changed