qlcnic_83xx_poll_process_aen(adapter);
 
-       if (ahw->diag_test == QLCNIC_INTERRUPT_TEST) {
-               ahw->diag_cnt++;
+       if (ahw->diag_test) {
+               if (ahw->diag_test == QLCNIC_INTERRUPT_TEST)
+                       ahw->diag_cnt++;
                qlcnic_83xx_enable_legacy_msix_mbx_intr(adapter);
                return IRQ_HANDLED;
        }
        }
 
        if (adapter->ahw->diag_test == QLCNIC_LOOPBACK_TEST) {
-               /* disable and free mailbox interrupt */
-               if (!(adapter->flags & QLCNIC_MSIX_ENABLED)) {
-                       qlcnic_83xx_enable_mbx_poll(adapter);
-                       qlcnic_83xx_free_mbx_intr(adapter);
-               }
                adapter->ahw->loopback_state = 0;
                adapter->ahw->hw_ops->setup_link_event(adapter, 1);
        }
 {
        struct qlcnic_adapter *adapter = netdev_priv(netdev);
        struct qlcnic_host_sds_ring *sds_ring;
-       int ring, err;
+       int ring;
 
        clear_bit(__QLCNIC_DEV_UP, &adapter->state);
        if (adapter->ahw->diag_test == QLCNIC_INTERRUPT_TEST) {
                for (ring = 0; ring < adapter->drv_sds_rings; ring++) {
                        sds_ring = &adapter->recv_ctx->sds_rings[ring];
-                       qlcnic_83xx_disable_intr(adapter, sds_ring);
-                       if (!(adapter->flags & QLCNIC_MSIX_ENABLED))
-                               qlcnic_83xx_enable_mbx_poll(adapter);
+                       if (adapter->flags & QLCNIC_MSIX_ENABLED)
+                               qlcnic_83xx_disable_intr(adapter, sds_ring);
                }
        }
 
        qlcnic_fw_destroy_ctx(adapter);
        qlcnic_detach(adapter);
 
-       if (adapter->ahw->diag_test == QLCNIC_LOOPBACK_TEST) {
-               if (!(adapter->flags & QLCNIC_MSIX_ENABLED)) {
-                       err = qlcnic_83xx_setup_mbx_intr(adapter);
-                       qlcnic_83xx_disable_mbx_poll(adapter);
-                       if (err) {
-                               dev_err(&adapter->pdev->dev,
-                                       "%s: failed to setup mbx interrupt\n",
-                                       __func__);
-                               goto out;
-                       }
-               }
-       }
        adapter->ahw->diag_test = 0;
        adapter->drv_sds_rings = drv_sds_rings;
 
        if (netif_running(netdev))
                __qlcnic_up(adapter, netdev);
 
-       if (adapter->ahw->diag_test == QLCNIC_INTERRUPT_TEST &&
-           !(adapter->flags & QLCNIC_MSIX_ENABLED))
-               qlcnic_83xx_disable_mbx_poll(adapter);
 out:
        netif_device_attach(netdev);
 }