diff --git a/vram/MemArbiter.bsv b/vram/MemArbiter.bsv
index 9807e94..4138c14 100644
--- a/vram/MemArbiter.bsv
+++ b/vram/MemArbiter.bsv
@@ -19,14 +19,14 @@ endinterface
 // A MemArbiterClient emits requests for memory access and emits
 // grants.
 interface MemArbiterClient#(type request);
-   method request request();
+   method Maybe#(request) request();
    method Action grant();
 endinterface
 
 instance Connectable#(MemArbiterClient#(req), MemArbiterServer#(req));
    module mkConnection(MemArbiterClient#(req) client, MemArbiterServer#(req) server, Empty ifc);
-      rule send_request;
-         server.request(client.request());
+      rule send_request (client.request matches tagged Valid .req);
+         server.request(req);
       endrule
 
       rule send_grant (server.grant());