=== modified file 'src/xfns.c'
--- src/xfns.c	2013-12-03 17:22:05 +0000
+++ src/xfns.c	2013-12-09 17:50:35 +0000
@@ -136,6 +136,20 @@
 
 static struct x_display_info *x_display_info_for_name (Lisp_Object);
 
+bool
+x_display_valid (Display *d)
+{
+  fd_set fdset;
+  struct timespec timeout;
+  int fd = ConnectionNumber (d); 
+
+  FD_ZERO (&fdset);
+  FD_SET (fd, &fdset);
+  timeout.tv_sec = 0;
+  timeout.tv_nsec = 1000;
+  return pselect (fd + 1, &fdset, NULL, NULL, &timeout, NULL) != -1;
+}
+
 /* Let the user specify an X display with a Lisp object.
    OBJECT may be nil, a frame or a terminal object.
    nil stands for the selected frame--or, if that is not an X frame,

=== modified file 'src/xfont.c'
--- src/xfont.c	2013-11-04 06:09:03 +0000
+++ src/xfont.c	2013-12-09 17:47:41 +0000
@@ -897,7 +897,8 @@
   if (xfi->xfont)
     {
       block_input ();
-      XFreeFont (xfi->display, xfi->xfont);
+      if (x_display_valid (xfi->display))
+	XFreeFont (xfi->display, xfi->xfont);
       unblock_input ();
       xfi->xfont = NULL;
     }

=== modified file 'src/xftfont.c'
--- src/xftfont.c	2013-10-27 05:30:34 +0000
+++ src/xftfont.c	2013-12-09 17:48:47 +0000
@@ -495,7 +495,8 @@
     {
       block_input ();
       XftUnlockFace (xftfont_info->xftfont);
-      XftFontClose (xftfont_info->display, xftfont_info->xftfont);
+      if (x_display_valid (xftfont_info->display))
+	XftFontClose (xftfont_info->display, xftfont_info->xftfont);
       unblock_input ();
       xftfont_info->xftfont = NULL;
     }

=== modified file 'src/xterm.h'
--- src/xterm.h	2013-12-07 23:04:10 +0000
+++ src/xterm.h	2013-12-09 17:46:16 +0000
@@ -989,6 +989,7 @@
 /* Defined in xfns.c */
 
 extern Lisp_Object x_get_focus_frame (struct frame *);
+extern bool x_display_valid (Display *);
 
 #ifdef USE_GTK
 extern int xg_set_icon (struct frame *, Lisp_Object);