diff --git a/os/connection.c b/os/connection.c
index c143fb6d3..77910be52 100644
--- a/os/connection.c
+++ b/os/connection.c
@@ -1033,6 +1033,9 @@ CloseDownConnection(ClientPtr client)
 {
     OsCommPtr oc = (OsCommPtr)client->osPrivate;
 
+    if (FlushCallback)
+	CallCallbacks(&FlushCallback, NULL);
+
     if (oc->output && oc->output->count)
 	FlushClient(client, oc, (char *)NULL, 0);
 #ifdef XDMCP
diff --git a/os/io.c b/os/io.c
index b5f98b7fa..e2df2e3ed 100644
--- a/os/io.c
+++ b/os/io.c
@@ -819,6 +819,10 @@ WriteToClient (ClientPtr who, int count, const void *__buf)
 	  CriticalOutputPending = FALSE;
 	  NewOutputPending = FALSE;
 	}
+
+	if (FlushCallback)
+	    CallCallbacks(&FlushCallback, NULL);
+
 	return FlushClient(who, oc, buf, count);
     }