Check the active port MTU against the MTU statically configured for the HCA. QLogic HCA's capable of MTU had an issue when connected to switches running at 2K.

This commit was SVN r20131.

ompi/mca/btl/openib/btl_openib_component.c

@@ -1749,6 +1749,13 @@ static int init_one_device(opal_list_t *btl_list, struct ibv_device* ib_dev)
             break;
         }
         if(IBV_PORT_ACTIVE == ib_port_attr.state) {
+	    /* Select the lower of the HCA and port active speed. With QLogic
+               HCAs that are capable of 4K MTU we had an issue when connected
+               to switches with 2K MTU. This fix is valid for other IB vendors
+               as well. */
+            if (ib_port_attr.active_mtu < device->mtu){
+                device->mtu = ib_port_attr.active_mtu;
+            }
             if (mca_btl_openib_component.apm_ports && device->btls > 0) {
                 init_apm_port(device, i, ib_port_attr.lid);
                 break;