diff --git a/src/xcb_io.c b/src/xcb_io.c
index d40ac102..ebb9d028 100644
--- a/src/xcb_io.c
+++ b/src/xcb_io.c
@@ -186,6 +186,8 @@ static void process_responses(Display *dpy, int wait_for_first_event, xcb_generi
 
 int _XEventsQueued(Display *dpy, int mode)
 {
+	if(dpy->flags & XlibDisplayIOError)
+		return 0;
 	if(dpy->xcb->event_owner != XlibOwnsEventQueue)
 		return 0;
 
@@ -202,6 +204,8 @@ int _XEventsQueued(Display *dpy, int mode)
  */
 void _XReadEvents(Display *dpy)
 {
+	if(dpy->flags & XlibDisplayIOError)
+		return;
 	_XSend(dpy, 0, 0);
 	if(dpy->xcb->event_owner != XlibOwnsEventQueue)
 		return;
@@ -219,6 +223,8 @@ void _XReadEvents(Display *dpy)
 void _XSend(Display *dpy, const char *data, long size)
 {
 	xcb_connection_t *c = dpy->xcb->connection;
+	if(dpy->flags & XlibDisplayIOError)
+		return;
 
 	assert(!dpy->xcb->request_extra);
 	dpy->xcb->request_extra = data;
@@ -356,6 +362,9 @@ Status _XReply(Display *dpy, xReply *rep, int extra, Bool discard)
 
 	assert(!dpy->xcb->reply_data);
 
+	if(dpy->flags & XlibDisplayIOError)
+		return 0;
+
 	/* Internals of UnlockDisplay done by hand here, so that we can
 	   insert_pending_request *after* we _XPutXCBBuffer, but before we
 	   unlock the display. */
diff --git a/src/xcb_lock.c b/src/xcb_lock.c
index 96386f31..0f661c53 100644
--- a/src/xcb_lock.c
+++ b/src/xcb_lock.c
@@ -19,18 +19,22 @@ static void _XCBLockDisplay(Display *dpy)
 	dpy->xcb->lock_fns.lock_display(dpy);
     if(!dpy->lock || dpy->lock->locking_level == 0)
 	xcb_xlib_lock(dpy->xcb->connection);
-    _XGetXCBBuffer(dpy);
+    if(!(dpy->flags & XlibDisplayIOError))
+	_XGetXCBBuffer(dpy);
 }
 
 static void _XCBUnlockDisplay(Display *dpy)
 {
-    _XPutXCBBuffer(dpy);
-    assert(dpy->xcb->partial_request == 0);
-    assert(xcb_get_request_sent(dpy->xcb->connection) == dpy->request);
+    if(!(dpy->flags & XlibDisplayIOError))
+    {
+	_XPutXCBBuffer(dpy);
+	assert(dpy->xcb->partial_request == 0);
+	assert(xcb_get_request_sent(dpy->xcb->connection) == dpy->request);
 
-    /* Traditional Xlib does this in _XSend; see the Xlib/XCB version
-     * of that function for why we do it here instead. */
-    _XSetSeqSyncFunction(dpy);
+	/* Traditional Xlib does this in _XSend; see the Xlib/XCB version
+	 * of that function for why we do it here instead. */
+	_XSetSeqSyncFunction(dpy);
+    }
 
     if(!dpy->lock || dpy->lock->locking_level == 0)
 	xcb_xlib_unlock(dpy->xcb->connection);