diff --git a/libs/ardour/ardour/plugin.h b/libs/ardour/ardour/plugin.h
index 279c689587..0557c7cffd 100644
--- a/libs/ardour/ardour/plugin.h
+++ b/libs/ardour/ardour/plugin.h
@@ -315,7 +315,7 @@ public:
 
 	virtual bool reconfigure_io (ChanCount /*in*/, ChanCount /*aux_in*/, ChanCount /*out*/) { return true; }
 	virtual bool match_variable_io (ChanCount& /*in*/, ChanCount& /*aux_in*/, ChanCount& /*out*/) { return false; }
-	virtual void request_bus_layout (ChanCount const& /*in*/, ChanCount const& /*aux_in*/, ChanCount const& /*out*/);
+	virtual void request_bus_layout (ChanCount const& /*in*/, ChanCount const& /*aux_in*/, ChanCount const& /*out*/) { }
 
 	virtual ChanCount output_streams () const;
 	virtual ChanCount input_streams () const;