diff --git a/sys/dev/if_ndis/if_ndis.c b/sys/dev/if_ndis/if_ndis.c
index 993f9a2..06d1162 100644
--- sys/dev/if_ndis/if_ndis.c
+++ sys/dev/if_ndis/if_ndis.c
@@ -161,7 +161,7 @@ static void ndis_scan_curchan	(struct ieee80211_scan_state *, unsigned long);
 static void ndis_scan_mindwell	(struct ieee80211_scan_state *);
 static void ndis_init		(void *);
 static void ndis_stop		(struct ndis_softc *);
-static void ndis_watchdog	(struct ifnet *);
+static void ndis_watchdog	(void *);
 static int ndis_ifmedia_upd	(struct ifnet *);
 static void ndis_ifmedia_sts	(struct ifnet *, struct ifmediareq *);
 static void ndis_auth		(void *, int);
@@ -690,12 +690,14 @@ ndis_attach(dev)
 	/* Check for task offload support. */
 	ndis_probe_offload(sc);
 
+	/* Initialize the Watchdog callout. */
+	callout_init(&sc->ndis_timer, CALLOUT_MPSAFE);
+
 	if_initname(ifp, device_get_name(dev), device_get_unit(dev));
 	ifp->if_mtu = ETHERMTU;
 	ifp->if_flags = IFF_BROADCAST | IFF_SIMPLEX | IFF_MULTICAST;
 	ifp->if_ioctl = ndis_ioctl;
 	ifp->if_start = ndis_start;
-	ifp->if_watchdog = ndis_watchdog;
 	ifp->if_init = ndis_init;
 	ifp->if_baudrate = 10000000;
 	IFQ_SET_MAXLEN(&ifp->if_snd, 50);
@@ -994,6 +996,7 @@ ndis_detach(dev)
 	driver_object		*drv;
 
 	sc = device_get_softc(dev);
+
 	NDIS_LOCK(sc);
 	ifp = sc->ifp;
 	ifp->if_flags &= ~IFF_UP;
@@ -1008,6 +1011,9 @@ ndis_detach(dev)
 	} else
 		NDIS_UNLOCK(sc);
 
+	/* Remove any pending callouts. */
+	callout_drain(&sc->ndis_timer);
+
 	if (sc->ndis_80211) {
 		taskqueue_drain(sc->ndis_tq, &sc->ndis_scantask);
 		taskqueue_drain(sc->ndis_tq, &sc->ndis_authtask);
@@ -1540,7 +1546,7 @@ ndis_txeof(adapter, packet, status)
 	else
 		ifp->if_oerrors++;
 
-	ifp->if_timer = 0;
+	callout_stop(&sc->ndis_timer);
 	ifp->if_drv_flags &= ~IFF_DRV_OACTIVE;
 
 	NDIS_UNLOCK(sc);
@@ -1888,7 +1894,7 @@ ndis_start(ifp)
 	/*
 	 * Set a timeout in case the chip goes out to lunch.
 	 */
-	ifp->if_timer = 5;
+	callout_reset(&sc->ndis_timer, 5 * hz, ndis_watchdog, sc);
 
 	NDIS_UNLOCK(sc);
 
@@ -3113,15 +3119,12 @@ ndis_resettask(d, arg)
 }
 
 static void
-ndis_watchdog(ifp)
-	struct ifnet		*ifp;
+ndis_watchdog (void *arg)
 {
-	struct ndis_softc		*sc;
-
-	sc = ifp->if_softc;
+	struct ndis_softc *sc = arg;
 
 	NDIS_LOCK(sc);
-	ifp->if_oerrors++;
+	sc->ifp->if_oerrors++;
 	device_printf(sc->ndis_dev, "watchdog timeout\n");
 	NDIS_UNLOCK(sc);
 
@@ -3130,7 +3133,7 @@ ndis_watchdog(ifp)
 	    WORKQUEUE_CRITICAL, sc);
 	IoQueueWorkItem(sc->ndis_startitem,
 	    (io_workitem_func)ndis_starttask_wrap,
-	    WORKQUEUE_CRITICAL, ifp);
+	    WORKQUEUE_CRITICAL, sc->ifp);
 
 	return;
 }
@@ -3150,7 +3153,7 @@ ndis_stop(sc)
 	callout_drain(&sc->ndis_stat_callout);
 
 	NDIS_LOCK(sc);
-	ifp->if_timer = 0;
+	callout_stop(&sc->ndis_timer);
 	sc->ndis_link = 0;
 	ifp->if_drv_flags &= ~(IFF_DRV_RUNNING | IFF_DRV_OACTIVE);
 	NDIS_UNLOCK(sc);
diff --git a/sys/dev/if_ndis/if_ndisvar.h b/sys/dev/if_ndis/if_ndisvar.h
index bf4f056..be8bf0a 100644
--- sys/dev/if_ndis/if_ndisvar.h
+++ sys/dev/if_ndis/if_ndisvar.h
@@ -181,6 +181,7 @@ struct ndis_softc {
 	struct task		ndis_assoctask;
 	int			(*ndis_newstate)(struct ieee80211com *,
 				    enum ieee80211_state, int);
+	struct callout		ndis_timer;
 };
 
 #define NDIS_LOCK(_sc)		KeAcquireSpinLock(&(_sc)->ndis_spinlock, \