First round of converting network drivers from spls to mutexes. This

takes care of all the 10/100 and gigE PCI drivers that I've done.
Next will be the wireless drivers, then the USB ones. I may pick up
some stragglers along the way. I'm sort of playing this by ear: if
anyone spots any places where I've screwed up horribly, please let me
know.

32 files changed, 788 insertions, 399 deletions

diff --git a/sys/dev/dc/if_dc.c b/sys/dev/dc/if_dc.c
index 695b019..f7c97a1 100644
--- a/sys/dev/dc/if_dc.c
+++ b/sys/dev/dc/if_dc.c
@@ -109,6 +109,7 @@
 #include <machine/bus_memio.h>
 #include <machine/bus.h>
 #include <machine/resource.h>
+#include <machine/mutex.h>
 #include <sys/bus.h>
 #include <sys/rman.h>
 
@@ -555,9 +556,9 @@ static int dc_mii_readreg(sc, frame)
 	struct dc_mii_frame	*frame;
 	
 {
-	int			i, ack, s;
+	int			i, ack;
 
-	s = splimp();
+	DC_LOCK(sc);
 
 	/*
 	 * Set up frame for RX.
@@ -612,7 +613,7 @@ fail:
 	dc_mii_writebit(sc, 0);
 	dc_mii_writebit(sc, 0);
 
-	splx(s);
+	DC_UNLOCK(sc);
 
 	if (ack)
 		return(1);
@@ -627,9 +628,7 @@ static int dc_mii_writereg(sc, frame)
 	struct dc_mii_frame	*frame;
 	
 {
-	int			s;
-
-	s = splimp();
+	DC_LOCK(sc);
 	/*
 	 * Set up frame for TX.
 	 */
@@ -654,7 +653,7 @@ static int dc_mii_writereg(sc, frame)
 	dc_mii_writebit(sc, 0);
 	dc_mii_writebit(sc, 0);
 
-	splx(s);
+	DC_UNLOCK(sc);
 
 	return(0);
 }
@@ -1626,7 +1625,7 @@ static void dc_parse_21143_srom(sc)
 static int dc_attach(dev)
 	device_t		dev;
 {
-	int			s, tmp = 0;
+	int			tmp = 0;
 	u_char			eaddr[ETHER_ADDR_LEN];
 	u_int32_t		command;
 	struct dc_softc		*sc;
@@ -1634,8 +1633,6 @@ static int dc_attach(dev)
 	u_int32_t		revision;
 	int			unit, error = 0, rid, mac_offset;
 
-	s = splimp();
-
 	sc = device_get_softc(dev);
 	unit = device_get_unit(dev);
 	bzero(sc, sizeof(struct dc_softc));
@@ -1701,7 +1698,9 @@ static int dc_attach(dev)
 		printf("dc%d: couldn't set up irq\n", unit);
 		goto fail;
 	}
-	
+
+	mtx_init(&sc->dc_mtx, "dc", MTX_DEF);
+	DC_LOCK(sc);
 	/* Need this info to decide on a chip type. */
 	sc->dc_info = dc_devtype(dev);
 	revision = pci_read_config(dev, DC_PCI_CFRV, 4) & 0x000000FF;
@@ -1966,10 +1965,12 @@ static int dc_attach(dev)
 	}
 #endif
 
+	DC_UNLOCK(sc);
+	return(0);
 
 fail:
-	splx(s);
-
+	DC_UNLOCK(sc);
+	mtx_destroy(&sc->dc_mtx);
 	return(error);
 }
 
@@ -1978,12 +1979,12 @@ static int dc_detach(dev)
 {
 	struct dc_softc		*sc;
 	struct ifnet		*ifp;
-	int			s;
 	struct dc_mediainfo	*m;
 
-	s = splimp();
-
 	sc = device_get_softc(dev);
+
+	DC_LOCK(sc);
+
 	ifp = &sc->arpcom.ac_if;
 
 	dc_stop(sc);
@@ -2006,7 +2007,8 @@ static int dc_detach(dev)
 		sc->dc_mi = m;
 	}
 
-	splx(s);
+	DC_UNLOCK(sc);
+	mtx_destroy(&sc->dc_mtx);
 
 	return(0);
 }
@@ -2457,12 +2459,10 @@ static void dc_tick(xsc)
 	struct dc_softc		*sc;
 	struct mii_data		*mii;
 	struct ifnet		*ifp;
-	int			s;
 	u_int32_t		r;
 
-	s = splimp();
-
 	sc = xsc;
+	DC_LOCK(sc);
 	ifp = &sc->arpcom.ac_if;
 	mii = device_get_softc(sc->dc_miibus);
 
@@ -2526,7 +2526,7 @@ static void dc_tick(xsc)
 	else
 		sc->dc_stat_ch = timeout(dc_tick, sc, hz);
 
-	splx(s);
+	DC_UNLOCK(sc);
 
 	return;
 }
@@ -2539,12 +2539,14 @@ static void dc_intr(arg)
 	u_int32_t		status;
 
 	sc = arg;
+	DC_LOCK(sc);
 	ifp = &sc->arpcom.ac_if;
 
 	/* Supress unwanted interrupts */
 	if (!(ifp->if_flags & IFF_UP)) {
 		if (CSR_READ_4(sc, DC_ISR) & DC_INTRS)
 			dc_stop(sc);
+		DC_UNLOCK(sc);
 		return;
 	}
 
@@ -2621,6 +2623,8 @@ static void dc_intr(arg)
 	if (ifp->if_snd.ifq_head != NULL)
 		dc_start(ifp);
 
+	DC_UNLOCK(sc);
+
 	return;
 }
 
@@ -2737,11 +2741,17 @@ static void dc_start(ifp)
 
 	sc = ifp->if_softc;
 
-	if (!sc->dc_link)
+	DC_LOCK(sc);
+
+	if (!sc->dc_link) {
+		DC_UNLOCK(sc);
 		return;
+	}
 
-	if (ifp->if_flags & IFF_OACTIVE)
+	if (ifp->if_flags & IFF_OACTIVE) {
+		DC_UNLOCK(sc);
 		return;
+	}
 
 	idx = sc->dc_cdata.dc_tx_prod;
 
@@ -2787,6 +2797,8 @@ static void dc_start(ifp)
 	 */
 	ifp->if_timer = 5;
 
+	DC_UNLOCK(sc);
+
 	return;
 }
 
@@ -2796,9 +2808,8 @@ static void dc_init(xsc)
 	struct dc_softc		*sc = xsc;
 	struct ifnet		*ifp = &sc->arpcom.ac_if;
 	struct mii_data		*mii;
-	int			s;
 
-	s = splimp();
+	DC_LOCK(sc);
 
 	mii = device_get_softc(sc->dc_miibus);
 
@@ -2876,7 +2887,7 @@ static void dc_init(xsc)
 		printf("dc%d: initialization failed: no "
 		    "memory for rx buffers\n", sc->dc_unit);
 		dc_stop(sc);
-		(void)splx(s);
+		DC_UNLOCK(sc);
 		return;
 	}
 
@@ -2929,8 +2940,6 @@ static void dc_init(xsc)
 	ifp->if_flags |= IFF_RUNNING;
 	ifp->if_flags &= ~IFF_OACTIVE;
 
-	(void)splx(s);
-
 	/* Don't start the ticker if this is a homePNA link. */
 	if (IFM_SUBTYPE(mii->mii_media.ifm_media) == IFM_homePNA)
 		sc->dc_link = 1;
@@ -2950,6 +2959,7 @@ static void dc_init(xsc)
 		sc->dc_srm_media = 0;
 	}
 #endif
+	DC_UNLOCK(sc);
 	return;
 }
 
@@ -3013,9 +3023,9 @@ static int dc_ioctl(ifp, command, data)
 	struct dc_softc		*sc = ifp->if_softc;
 	struct ifreq		*ifr = (struct ifreq *) data;
 	struct mii_data		*mii;
-	int			s, error = 0;
+	int			error = 0;
 
-	s = splimp();
+	DC_LOCK(sc);
 
 	switch(command) {
 	case SIOCSIFADDR:
@@ -3063,7 +3073,7 @@ static int dc_ioctl(ifp, command, data)
 		break;
 	}
 
-	(void)splx(s);
+	DC_UNLOCK(sc);
 
 	return(error);
 }
@@ -3075,6 +3085,8 @@ static void dc_watchdog(ifp)
 
 	sc = ifp->if_softc;
 
+	DC_LOCK(sc);
+
 	ifp->if_oerrors++;
 	printf("dc%d: watchdog timeout\n", sc->dc_unit);
 
@@ -3085,6 +3097,8 @@ static void dc_watchdog(ifp)
 	if (ifp->if_snd.ifq_head != NULL)
 		dc_start(ifp);
 
+	DC_UNLOCK(sc);
+
 	return;
 }
 
@@ -3098,6 +3112,8 @@ static void dc_stop(sc)
 	register int		i;
 	struct ifnet		*ifp;
 
+	DC_LOCK(sc);
+
 	ifp = &sc->arpcom.ac_if;
 	ifp->if_timer = 0;
 
@@ -3141,6 +3157,8 @@ static void dc_stop(sc)
 
 	ifp->if_flags &= ~(IFF_RUNNING | IFF_OACTIVE);
 
+	DC_UNLOCK(sc);
+
 	return;
 }
 
diff --git a/sys/dev/dc/if_dcreg.h b/sys/dev/dc/if_dcreg.h
index 9c6cfc4..e72d8b4 100644
--- a/sys/dev/dc/if_dcreg.h
+++ b/sys/dev/dc/if_dcreg.h
@@ -676,8 +676,13 @@ struct dc_softc {
 #ifdef SRM_MEDIA
 	int			dc_srm_media;
 #endif
+	struct mtx		dc_mtx;
 };
 
+
+#define	DC_LOCK(_sc)		mtx_enter(&(_sc)->dc_mtx, MTX_DEF)
+#define	DC_UNLOCK(_sc)		mtx_exit(&(_sc)->dc_mtx, MTX_DEF)
+
 #define DC_TX_POLL		0x00000001
 #define DC_TX_COALESCE		0x00000002
 #define DC_TX_ADMTEK_WAR	0x00000004
diff --git a/sys/dev/sf/if_sf.c b/sys/dev/sf/if_sf.c
index 52c6f88..a7d14522 100644
--- a/sys/dev/sf/if_sf.c
+++ b/sys/dev/sf/if_sf.c
@@ -531,9 +531,9 @@ static int sf_ioctl(ifp, command, data)
 	struct sf_softc		*sc = ifp->if_softc;
 	struct ifreq		*ifr = (struct ifreq *) data;
 	struct mii_data		*mii;
-	int			s, error = 0;
+	int			error = 0;
 
-	s = splimp();
+	SF_LOCK(sc);
 
 	switch(command) {
 	case SIOCSIFADDR:
@@ -575,7 +575,7 @@ static int sf_ioctl(ifp, command, data)
 		break;
 	}
 
-	(void)splx(s);
+	SF_UNLOCK(sc);
 
 	return(error);
 }
@@ -670,14 +670,12 @@ static int sf_probe(dev)
 static int sf_attach(dev)
 	device_t		dev;
 {
-	int			s, i;
+	int			i;
 	u_int32_t		command;
 	struct sf_softc		*sc;
 	struct ifnet		*ifp;
 	int			unit, rid, error = 0;
 
-	s = splimp();
-
 	sc = device_get_softc(dev);
 	unit = device_get_unit(dev);
 	bzero(sc, sizeof(struct sf_softc));
@@ -768,7 +766,8 @@ static int sf_attach(dev)
 	}
 
 	callout_handle_init(&sc->sf_stat_ch);
-
+	mtx_init(&sc->sf_mtx, "sf", MTX_DEF);
+	SF_LOCK(sc);
 	/* Reset the adapter. */
 	sf_reset(sc);
 
@@ -832,9 +831,12 @@ static int sf_attach(dev)
 	 * Call MI attach routine.
 	 */
 	ether_ifattach(ifp, ETHER_BPF_SUPPORTED);
+	SF_UNLOCK(sc);
+	return(0);
 
 fail:
-	splx(s);
+	SF_UNLOCK(sc);
+	mtx_destroy(&sc->sf_mtx);
 	return(error);
 }
 
@@ -843,11 +845,9 @@ static int sf_detach(dev)
 {
 	struct sf_softc		*sc;
 	struct ifnet		*ifp;
-	int			s;
-
-	s = splimp();
 
 	sc = device_get_softc(dev);
+	SF_LOCK(sc);
 	ifp = &sc->arpcom.ac_if;
 
 	ether_ifdetach(ifp, ETHER_BPF_SUPPORTED);
@@ -862,7 +862,8 @@ static int sf_detach(dev)
 
 	contigfree(sc->sf_ldata, sizeof(struct sf_list_data), M_DEVBUF);
 
-	splx(s);
+	SF_UNLOCK(sc);
+	mtx_destroy(&sc->sf_mtx);
 
 	return(0);
 }
@@ -1086,10 +1087,14 @@ static void sf_intr(arg)
 	u_int32_t		status;
 
 	sc = arg;
+	SF_LOCK(sc);
+
 	ifp = &sc->arpcom.ac_if;
 
-	if (!(csr_read_4(sc, SF_ISR_SHADOW) & SF_ISR_PCIINT_ASSERTED))
+	if (!(csr_read_4(sc, SF_ISR_SHADOW) & SF_ISR_PCIINT_ASSERTED)) {
+		SF_UNLOCK(sc);
 		return;
+	}
 
 	/* Disable interrupts. */
 	csr_write_4(sc, SF_IMR, 0x00000000);
@@ -1124,6 +1129,7 @@ static void sf_intr(arg)
 	if (ifp->if_snd.ifq_head != NULL)
 		sf_start(ifp);
 
+	SF_UNLOCK(sc);
 	return;
 }
 
@@ -1133,11 +1139,10 @@ static void sf_init(xsc)
 	struct sf_softc		*sc;
 	struct ifnet		*ifp;
 	struct mii_data		*mii;
-	int			i, s;
-
-	s = splimp();
+	int			i;
 
 	sc = xsc;
+	SF_LOCK(sc);
 	ifp = &sc->arpcom.ac_if;
 	mii = device_get_softc(sc->sf_miibus);
 
@@ -1162,7 +1167,7 @@ static void sf_init(xsc)
 	if (sf_init_rx_ring(sc) == ENOBUFS) {
 		printf("sf%d: initialization failed: no "
 		    "memory for rx buffers\n", sc->sf_unit);
-		(void)splx(s);
+		SF_UNLOCK(sc);
 		return;
 	}
 
@@ -1237,7 +1242,7 @@ static void sf_init(xsc)
 
 	sc->sf_stat_ch = timeout(sf_stats_update, sc, hz);
 
-	splx(s);
+	SF_UNLOCK(sc);
 
 	return;
 }
@@ -1314,12 +1319,17 @@ static void sf_start(ifp)
 	int			i, txprod;
 
 	sc = ifp->if_softc;
+	SF_LOCK(sc);
 
-	if (!sc->sf_link)
+	if (!sc->sf_link) {
+		SF_UNLOCK(sc);
 		return;
+	}
 
-	if (ifp->if_flags & IFF_OACTIVE)
+	if (ifp->if_flags & IFF_OACTIVE) {
+		SF_UNLOCK(sc);
 		return;
+	}
 
 	txprod = csr_read_4(sc, SF_TXDQ_PRODIDX);
 	i = SF_IDX_HI(txprod) >> 4;
@@ -1345,8 +1355,10 @@ static void sf_start(ifp)
 			break;
 	}
 
-	if (cur_tx == NULL)
+	if (cur_tx == NULL) {
+		SF_UNLOCK(sc);
 		return;
+	}
 
 	/* Transmit */
 	csr_write_4(sc, SF_TXDQ_PRODIDX,
@@ -1355,6 +1367,8 @@ static void sf_start(ifp)
 
 	ifp->if_timer = 5;
 
+	SF_UNLOCK(sc);
+
 	return;
 }
 
@@ -1364,6 +1378,8 @@ static void sf_stop(sc)
 	int			i;
 	struct ifnet		*ifp;
 
+	SF_LOCK(sc);
+
 	ifp = &sc->arpcom.ac_if;
 
 	untimeout(sf_stats_update, sc, sc->sf_stat_ch);
@@ -1396,6 +1412,7 @@ static void sf_stop(sc)
 	}
 
 	ifp->if_flags &= ~(IFF_RUNNING|IFF_OACTIVE);
+	SF_UNLOCK(sc);
 
 	return;
 }
@@ -1415,11 +1432,10 @@ static void sf_stats_update(xsc)
 	struct mii_data		*mii;
 	struct sf_stats		stats;
 	u_int32_t		*ptr;
-	int			i, s;
-
-	s = splimp();
+	int			i;
 
 	sc = xsc;
+	SF_LOCK(sc);
 	ifp = &sc->arpcom.ac_if;
 	mii = device_get_softc(sc->sf_miibus);
 
@@ -1447,7 +1463,7 @@ static void sf_stats_update(xsc)
 
 	sc->sf_stat_ch = timeout(sf_stats_update, sc, hz);
 
-	splx(s);
+	SF_UNLOCK(sc);
 
 	return;
 }
@@ -1459,6 +1475,8 @@ static void sf_watchdog(ifp)
 
 	sc = ifp->if_softc;
 
+	SF_LOCK(sc);
+
 	ifp->if_oerrors++;
 	printf("sf%d: watchdog timeout\n", sc->sf_unit);
 
@@ -1469,6 +1487,8 @@ static void sf_watchdog(ifp)
 	if (ifp->if_snd.ifq_head != NULL)
 		sf_start(ifp);
 
+	SF_UNLOCK(sc);
+
 	return;
 }
 
diff --git a/sys/dev/sf/if_sfreg.h b/sys/dev/sf/if_sfreg.h
index 49fdd5a..c2dc20e 100644
--- a/sys/dev/sf/if_sfreg.h
+++ b/sys/dev/sf/if_sfreg.h
@@ -1044,8 +1044,13 @@ struct sf_softc {
 	u_int8_t		sf_link;
 	int			sf_if_flags;
 	struct callout_handle	sf_stat_ch;
+	struct mtx		sf_mtx;
 };
 
+
+#define	SF_LOCK(_sc)		mtx_enter(&(_sc)->sf_mtx, MTX_DEF)
+#define	SF_UNLOCK(_sc)		mtx_exit(&(_sc)->sf_mtx, MTX_DEF)
+
 #define SF_TIMEOUT	1000
 
 #ifdef __alpha__
diff --git a/sys/dev/sk/if_sk.c b/sys/dev/sk/if_sk.c
index a83a606..963f754 100644
--- a/sys/dev/sk/if_sk.c
+++ b/sys/dev/sk/if_sk.c
@@ -413,6 +413,8 @@ static int sk_miibus_readreg(dev, phy, reg)
 	if (sc_if->sk_phytype == SK_PHYTYPE_XMAC && phy != 0)
 		return(0);
 
+	SK_IF_LOCK(sc_if);
+
 	SK_XM_WRITE_2(sc_if, XM_PHY_ADDR, reg|(phy << 8));
 	SK_XM_READ_2(sc_if, XM_PHY_DATA);
 	if (sc_if->sk_phytype != SK_PHYTYPE_XMAC) {
@@ -430,7 +432,9 @@ static int sk_miibus_readreg(dev, phy, reg)
 		}
 	}
 	DELAY(1);
-	return(SK_XM_READ_2(sc_if, XM_PHY_DATA));
+	i = SK_XM_READ_2(sc_if, XM_PHY_DATA);
+	SK_IF_UNLOCK(sc_if);
+	return(i);
 }
 
 static int sk_miibus_writereg(dev, phy, reg, val)
@@ -441,6 +445,7 @@ static int sk_miibus_writereg(dev, phy, reg, val)
 	int			i;
 
 	sc_if = device_get_softc(dev);
+	SK_IF_LOCK(sc_if);
 
 	SK_XM_WRITE_2(sc_if, XM_PHY_ADDR, reg|(phy << 8));
 	for (i = 0; i < SK_TIMEOUT; i++) {
@@ -460,6 +465,8 @@ static int sk_miibus_writereg(dev, phy, reg, val)
 			break;
 	}
 
+	SK_IF_UNLOCK(sc_if);
+
 	if (i == SK_TIMEOUT)
 		printf("sk%d: phy write timed out\n", sc_if->sk_unit);
 
@@ -474,7 +481,7 @@ static void sk_miibus_statchg(dev)
 
 	sc_if = device_get_softc(dev);
 	mii = device_get_softc(sc_if->sk_miibus);
-
+	SK_IF_LOCK(sc_if);
 	/*
 	 * If this is a GMII PHY, manually set the XMAC's
 	 * duplex mode accordingly.
@@ -486,6 +493,7 @@ static void sk_miibus_statchg(dev)
 			SK_XM_CLRBIT_2(sc_if, XM_MMUCMD, XM_MMUCMD_GMIIFDX);
 		}
 	}
+	SK_IF_UNLOCK(sc_if);
 
 	return;
 }
@@ -872,10 +880,10 @@ static int sk_ioctl(ifp, command, data)
 {
 	struct sk_if_softc	*sc_if = ifp->if_softc;
 	struct ifreq		*ifr = (struct ifreq *) data;
-	int			s, error = 0;
+	int			error = 0;
 	struct mii_data		*mii;
 
-	s = splimp();
+	SK_IF_LOCK(sc_if);
 
 	switch(command) {
 	case SIOCSIFADDR:
@@ -928,7 +936,7 @@ static int sk_ioctl(ifp, command, data)
 		break;
 	}
 
-	(void)splx(s);
+	SK_IF_UNLOCK(sc_if);
 
 	return(error);
 }
@@ -1025,6 +1033,7 @@ static int sk_attach_xmac(dev)
 
 	sc_if = device_get_softc(dev);
 	sc = device_get_softc(device_get_parent(dev));
+	SK_LOCK(sc);
 	port = *(int *)device_get_ivars(dev);
 	free(device_get_ivars(dev), M_DEVBUF);
 	device_set_ivars(dev, NULL);
@@ -1113,6 +1122,7 @@ static int sk_attach_xmac(dev)
 	if (sc_if->sk_rdata == NULL) {
 		printf("sk%d: no memory for list buffers!\n", sc_if->sk_unit);
 		sc->sk_if[port] = NULL;
+		SK_UNLOCK(sc);
 		return(ENOMEM);
 	}
 
@@ -1125,6 +1135,7 @@ static int sk_attach_xmac(dev)
 		contigfree(sc_if->sk_rdata,
 		    sizeof(struct sk_ring_data), M_DEVBUF);
 		sc->sk_if[port] = NULL;
+		SK_UNLOCK(sc);
 		return(ENOMEM);
 	}
 
@@ -1151,6 +1162,7 @@ static int sk_attach_xmac(dev)
 		printf("skc%d: no PHY found!\n", sc_if->sk_unit);
 		contigfree(sc_if->sk_rdata,
 		    sizeof(struct sk_ring_data), M_DEVBUF);
+		SK_UNLOCK(sc);
 		return(ENXIO);
 	}
 
@@ -1160,6 +1172,8 @@ static int sk_attach_xmac(dev)
 	ether_ifattach(ifp, ETHER_BPF_SUPPORTED);
 	callout_handle_init(&sc_if->sk_tick_ch);
 
+	SK_UNLOCK(sc);
+
 	return(0);
 }
 
@@ -1170,13 +1184,10 @@ static int sk_attach_xmac(dev)
 static int sk_attach(dev)
 	device_t		dev;
 {
-	int			s;
 	u_int32_t		command;
 	struct sk_softc		*sc;
 	int			unit, error = 0, rid, *port;
 
-	s = splimp();
-
 	sc = device_get_softc(dev);
 	unit = device_get_unit(dev);
 	bzero(sc, sizeof(struct sk_softc));
@@ -1266,6 +1277,8 @@ static int sk_attach(dev)
 		goto fail;
 	}
 
+	mtx_init(&sc->sk_mtx, "skc", MTX_DEF);
+	SK_LOCK(sc);
 	/* Reset the adapter. */
 	sk_reset(sc);
 
@@ -1345,9 +1358,12 @@ static int sk_attach(dev)
 	CSR_WRITE_2(sc, SK_LED, SK_LED_GREEN_ON);
 
 	bus_generic_attach(dev);
+	SK_UNLOCK(sc);
+	return(0);
 
 fail:
-	splx(s);
+	SK_UNLOCK(sc);
+	mtx_destroy(&sc->sk_mtx);
 	return(error);
 }
 
@@ -1357,12 +1373,11 @@ static int sk_detach_xmac(dev)
 	struct sk_softc		*sc;
 	struct sk_if_softc	*sc_if;
 	struct ifnet		*ifp;
-	int			s;
-
-	s = splimp();
 
 	sc = device_get_softc(device_get_parent(dev));
 	sc_if = device_get_softc(dev);
+	SK_IF_LOCK(sc_if);
+
 	ifp = &sc_if->arpcom.ac_if;
 	sk_stop(sc_if);
 	ether_ifdetach(ifp, ETHER_BPF_SUPPORTED);
@@ -1371,6 +1386,7 @@ static int sk_detach_xmac(dev)
 		device_delete_child(dev, sc_if->sk_miibus);
 	contigfree(sc_if->sk_cdata.sk_jumbo_buf, SK_JMEM, M_DEVBUF);
 	contigfree(sc_if->sk_rdata, sizeof(struct sk_ring_data), M_DEVBUF);
+	SK_IF_UNLOCK(sc_if);
 
 	return(0);
 }
@@ -1379,11 +1395,9 @@ static int sk_detach(dev)
 	device_t		dev;
 {
 	struct sk_softc		*sc;
-	int			s;
-
-	s = splimp();
 
 	sc = device_get_softc(dev);
+	SK_LOCK(sc);
 
 	bus_generic_detach(dev);
 	if (sc->sk_devs[SK_PORT_A] != NULL)
@@ -1395,7 +1409,8 @@ static int sk_detach(dev)
 	bus_release_resource(dev, SYS_RES_IRQ, 0, sc->sk_irq);
 	bus_release_resource(dev, SK_RES, SK_RID, sc->sk_res);
 
-	splx(s);
+	SK_UNLOCK(sc);
+	mtx_destroy(&sc->sk_mtx);
 
 	return(0);
 }
@@ -1460,6 +1475,8 @@ static void sk_start(ifp)
 	sc_if = ifp->if_softc;
 	sc = sc_if->sk_softc;
 
+	SK_IF_LOCK(sc_if);
+
 	idx = sc_if->sk_cdata.sk_tx_prod;
 
 	while(sc_if->sk_cdata.sk_tx_chain[idx].sk_mbuf == NULL) {
@@ -1492,6 +1509,7 @@ static void sk_start(ifp)
 
 	/* Set a timeout in case the chip goes out to lunch. */
 	ifp->if_timer = 5;
+	SK_IF_UNLOCK(sc_if);
 
 	return;
 }
@@ -1516,6 +1534,7 @@ static void sk_shutdown(dev)
 	struct sk_softc		*sc;
 
 	sc = device_get_softc(dev);
+	SK_LOCK(sc);
 
 	/* Turn off the 'driver is loaded' LED. */
 	CSR_WRITE_2(sc, SK_LED, SK_LED_GREEN_OFF);
@@ -1525,6 +1544,7 @@ static void sk_shutdown(dev)
 	 * assert the resets on the attached XMAC(s).
 	 */
 	sk_reset(sc);
+	SK_UNLOCK(sc);
 
 	return;
 }
@@ -1644,14 +1664,18 @@ static void sk_tick(xsc_if)
 	int			i;
 
 	sc_if = xsc_if;
+	SK_IF_LOCK(sc_if);
 	ifp = &sc_if->arpcom.ac_if;
 	mii = device_get_softc(sc_if->sk_miibus);
 
-	if (!(ifp->if_flags & IFF_UP))
+	if (!(ifp->if_flags & IFF_UP)) {
+		SK_IF_UNLOCK(sc_if);
 		return;
+	}
 
 	if (sc_if->sk_phytype == SK_PHYTYPE_BCOM) {
 		sk_intr_bcom(sc_if);
+		SK_IF_UNLOCK(sc_if);
 		return;
 	}
 
@@ -1669,6 +1693,7 @@ static void sk_tick(xsc_if)
 
 	if (i != 3) {
 		sc_if->sk_tick_ch = timeout(sk_tick, sc_if, hz);
+		SK_IF_UNLOCK(sc_if);
 		return;
 	}
 
@@ -1679,6 +1704,7 @@ static void sk_tick(xsc_if)
 	mii_pollstat(mii);
 	untimeout(sk_tick, sc_if, sc_if->sk_tick_ch);
 
+	SK_IF_UNLOCK(sc_if);
 	return;
 }
 
@@ -1785,6 +1811,8 @@ static void sk_intr(xsc)
 	struct ifnet		*ifp0 = NULL, *ifp1 = NULL;
 	u_int32_t		status;
 
+	SK_LOCK(sc);
+
 	sc_if0 = sc->sk_if[SK_PORT_A];
 	sc_if1 = sc->sk_if[SK_PORT_B];
 
@@ -1846,6 +1874,8 @@ static void sk_intr(xsc)
 	if (ifp1 != NULL && ifp1->if_snd.ifq_head != NULL)
 		sk_start(ifp1);
 
+	SK_UNLOCK(sc);
+
 	return;
 }
 
@@ -2028,9 +2058,8 @@ static void sk_init(xsc)
 	struct sk_softc		*sc;
 	struct ifnet		*ifp;
 	struct mii_data		*mii;
-	int			s;
 
-	s = splimp();
+	SK_IF_LOCK(sc_if);
 
 	ifp = &sc_if->arpcom.ac_if;
 	sc = sc_if->sk_softc;
@@ -2100,7 +2129,7 @@ static void sk_init(xsc)
 		printf("sk%d: initialization failed: no "
 		    "memory for rx buffers\n", sc_if->sk_unit);
 		sk_stop(sc_if);
-		(void)splx(s);
+		SK_IF_UNLOCK(sc_if);
 		return;
 	}
 	sk_init_tx_ring(sc_if);
@@ -2126,7 +2155,7 @@ static void sk_init(xsc)
 	ifp->if_flags |= IFF_RUNNING;
 	ifp->if_flags &= ~IFF_OACTIVE;
 
-	splx(s);
+	SK_IF_UNLOCK(sc_if);
 
 	return;
 }
@@ -2138,6 +2167,7 @@ static void sk_stop(sc_if)
 	struct sk_softc		*sc;
 	struct ifnet		*ifp;
 
+	SK_IF_LOCK(sc_if);
 	sc = sc_if->sk_softc;
 	ifp = &sc_if->arpcom.ac_if;
 
@@ -2198,6 +2228,6 @@ static void sk_stop(sc_if)
 	}
 
 	ifp->if_flags &= ~(IFF_RUNNING|IFF_OACTIVE);
-
+	SK_IF_UNLOCK(sc_if);
 	return;
 }
diff --git a/sys/dev/sk/if_skreg.h b/sys/dev/sk/if_skreg.h
index 92a26be..6f31d1d 100644
--- a/sys/dev/sk/if_skreg.h
+++ b/sys/dev/sk/if_skreg.h
@@ -1179,8 +1179,14 @@ struct sk_softc {
 	u_int32_t		sk_intrmask;
 	struct sk_if_softc	*sk_if[2];
 	device_t		sk_devs[2];
+	struct mtx		sk_mtx;
 };
 
+#define	SK_LOCK(_sc)		mtx_enter(&(_sc)->sk_mtx, MTX_DEF)
+#define	SK_UNLOCK(_sc)		mtx_exit(&(_sc)->sk_mtx, MTX_DEF)
+#define	SK_IF_LOCK(_sc)		mtx_enter(&(_sc)->sk_softc->sk_mtx, MTX_DEF)
+#define	SK_IF_UNLOCK(_sc)	mtx_exit(&(_sc)->sk_softc->sk_mtx, MTX_DEF)
+
 /* Softc for each logical interface */
 struct sk_if_softc {
 	struct arpcom		arpcom;		/* interface info */
diff --git a/sys/dev/ti/if_ti.c b/sys/dev/ti/if_ti.c
index f1cfee5..04ec29d 100644
--- a/sys/dev/ti/if_ti.c
+++ b/sys/dev/ti/if_ti.c
@@ -1477,14 +1477,11 @@ static int ti_probe(dev)
 static int ti_attach(dev)
 	device_t		dev;
 {
-	int			s;
 	u_int32_t		command;
 	struct ifnet		*ifp;
 	struct ti_softc		*sc;
 	int			unit, error = 0, rid;
 
-	s = splimp();
-
 	sc = device_get_softc(dev);
 	unit = device_get_unit(dev);
 	bzero(sc, sizeof(struct ti_softc));
@@ -1540,6 +1537,9 @@ static int ti_attach(dev)
 		goto fail;
 	}
 
+	mtx_init(&sc->ti_mtx, "ti", MTX_DEF);
+	TI_LOCK(sc);
+
 	sc->ti_unit = unit;
 
 	if (ti_chipinit(sc)) {
@@ -1689,10 +1689,12 @@ static int ti_attach(dev)
 	 * Call MI attach routine.
 	 */
 	ether_ifattach(ifp, ETHER_BPF_SUPPORTED);
+	TI_UNLOCK(sc);
+	return(0);
 
 fail:
-	splx(s);
-
+	TI_UNLOCK(sc);
+	mtx_destroy(&sc->ti_mtx);
 	return(error);
 }
 
@@ -1701,11 +1703,10 @@ static int ti_detach(dev)
 {
 	struct ti_softc		*sc;
 	struct ifnet		*ifp;
-	int			s;
 
-	s = splimp();
 
 	sc = device_get_softc(dev);
+	TI_LOCK(sc);
 	ifp = &sc->arpcom.ac_if;
 
 	ether_ifdetach(ifp, ETHER_BPF_SUPPORTED);
@@ -1719,7 +1720,8 @@ static int ti_detach(dev)
 	contigfree(sc->ti_rdata, sizeof(struct ti_ring_data), M_DEVBUF);
 	ifmedia_removeall(&sc->ifmedia);
 
-	splx(s);
+	TI_UNLOCK(sc);
+	mtx_destroy(&sc->ti_mtx);
 
 	return(0);
 }
@@ -1907,13 +1909,16 @@ static void ti_intr(xsc)
 	struct ifnet		*ifp;
 
 	sc = xsc;
+	TI_LOCK(sc);
 	ifp = &sc->arpcom.ac_if;
 
 #ifdef notdef
 	/* Avoid this for now -- checking this register is expensive. */
 	/* Make sure this is really our interrupt. */
-	if (!(CSR_READ_4(sc, TI_MISC_HOST_CTL) & TI_MHC_INTSTATE))
+	if (!(CSR_READ_4(sc, TI_MISC_HOST_CTL) & TI_MHC_INTSTATE)) {
+		TI_UNLOCK(sc);
 		return;
+	}
 #endif
 
 	/* Ack interrupt and stop others from occuring. */
@@ -1935,6 +1940,8 @@ static void ti_intr(xsc)
 	if (ifp->if_flags & IFF_RUNNING && ifp->if_snd.ifq_head != NULL)
 		ti_start(ifp);
 
+	TI_UNLOCK(sc);
+
 	return;
 }
 
@@ -2069,6 +2076,7 @@ static void ti_start(ifp)
 	u_int32_t		prodidx = 0;
 
 	sc = ifp->if_softc;
+	TI_LOCK(sc);
 
 	prodidx = CSR_READ_4(sc, TI_MB_SENDPROD_IDX);
 
@@ -2121,6 +2129,7 @@ static void ti_start(ifp)
 	 * Set a timeout in case the chip goes out to lunch.
 	 */
 	ifp->if_timer = 5;
+	TI_UNLOCK(sc);
 
 	return;
 }
@@ -2129,21 +2138,19 @@ static void ti_init(xsc)
 	void			*xsc;
 {
 	struct ti_softc		*sc = xsc;
-        int			s;
-
-	s = splimp();
 
 	/* Cancel pending I/O and flush buffers. */
 	ti_stop(sc);
 
+	TI_LOCK(sc);
 	/* Init the gen info block, ring control blocks and firmware. */
 	if (ti_gibinit(sc)) {
 		printf("ti%d: initialization failure\n", sc->ti_unit);
-		splx(s);
+		TI_UNLOCK(sc);
 		return;
 	}
 
-	splx(s);
+	TI_UNLOCK(sc);
 
 	return;
 }
@@ -2355,10 +2362,10 @@ static int ti_ioctl(ifp, command, data)
 {
 	struct ti_softc		*sc = ifp->if_softc;
 	struct ifreq		*ifr = (struct ifreq *) data;
-	int			s, error = 0;
+	int			error = 0;
 	struct ti_cmd_desc	cmd;
 
-	s = splimp();
+	TI_LOCK(sc);
 
 	switch(command) {
 	case SIOCSIFADDR:
@@ -2419,7 +2426,7 @@ static int ti_ioctl(ifp, command, data)
 		break;
 	}
 
-	(void)splx(s);
+	TI_UNLOCK(sc);
 
 	return(error);
 }
@@ -2430,12 +2437,14 @@ static void ti_watchdog(ifp)
 	struct ti_softc		*sc;
 
 	sc = ifp->if_softc;
+	TI_LOCK(sc);
 
 	printf("ti%d: watchdog timeout -- resetting\n", sc->ti_unit);
 	ti_stop(sc);
 	ti_init(sc);
 
 	ifp->if_oerrors++;
+	TI_UNLOCK(sc);
 
 	return;
 }
@@ -2450,6 +2459,8 @@ static void ti_stop(sc)
 	struct ifnet		*ifp;
 	struct ti_cmd_desc	cmd;
 
+	TI_LOCK(sc);
+
 	ifp = &sc->arpcom.ac_if;
 
 	/* Disable host interrupts. */
@@ -2482,6 +2493,7 @@ static void ti_stop(sc)
 	sc->ti_tx_saved_considx = TI_TXCONS_UNSET;
 
 	ifp->if_flags &= ~(IFF_RUNNING | IFF_OACTIVE);
+	TI_UNLOCK(sc);
 
 	return;
 }
@@ -2496,8 +2508,9 @@ static void ti_shutdown(dev)
 	struct ti_softc		*sc;
 
 	sc = device_get_softc(dev);
-
+	TI_LOCK(sc);
 	ti_chipinit(sc);
+	TI_UNLOCK(sc);
 
 	return;
 }
diff --git a/sys/dev/ti/if_tireg.h b/sys/dev/ti/if_tireg.h
index 6346c67..d64cc7a 100644
--- a/sys/dev/ti/if_tireg.h
+++ b/sys/dev/ti/if_tireg.h
@@ -1148,8 +1148,12 @@ struct ti_softc {
 	u_int32_t		ti_tx_buf_ratio;
 	int			ti_if_flags;
 	int			ti_txcnt;
+	struct mtx		ti_mtx;
 };
 
+#define	TI_LOCK(_sc)		mtx_enter(&(_sc)->ti_mtx, MTX_DEF)
+#define	TI_UNLOCK(_sc)		mtx_exit(&(_sc)->ti_mtx, MTX_DEF)
+
 /*
  * Microchip Technology 24Cxx EEPROM control bytes
  */
diff --git a/sys/dev/vr/if_vr.c b/sys/dev/vr/if_vr.c
index 3649d7e..10b9942 100644
--- a/sys/dev/vr/if_vr.c
+++ b/sys/dev/vr/if_vr.c
@@ -285,9 +285,9 @@ static int vr_mii_readreg(sc, frame)
 	struct vr_mii_frame	*frame;
 	
 {
-	int			i, ack, s;
+	int			i, ack;
 
-	s = splimp();
+	VR_LOCK(sc);
 
 	/*
 	 * Set up frame for RX.
@@ -364,7 +364,7 @@ fail:
 	SIO_SET(VR_MIICMD_CLK);
 	DELAY(1);
 
-	splx(s);
+	VR_UNLOCK(sc);
 
 	if (ack)
 		return(1);
@@ -379,9 +379,7 @@ static int vr_mii_writereg(sc, frame)
 	struct vr_mii_frame	*frame;
 	
 {
-	int			s;
-
-	s = splimp();
+	VR_LOCK(sc);
 
 	CSR_WRITE_1(sc, VR_MIICMD, 0);
 	VR_SETBIT(sc, VR_MIICMD, VR_MIICMD_DIRECTPGM);
@@ -419,7 +417,7 @@ static int vr_mii_writereg(sc, frame)
 	 */
 	SIO_CLR(VR_MIICMD_DIR);
 
-	splx(s);
+	VR_UNLOCK(sc);
 
 	return(0);
 }
@@ -467,8 +465,10 @@ static void vr_miibus_statchg(dev)
 	struct mii_data		*mii;
 
 	sc = device_get_softc(dev);
+	VR_LOCK(sc);
 	mii = device_get_softc(sc->vr_miibus);
 	vr_setcfg(sc, mii->mii_media_active);
+	VR_UNLOCK(sc);
 
 	return;
 }
@@ -633,15 +633,13 @@ static int vr_probe(dev)
 static int vr_attach(dev)
 	device_t		dev;
 {
-	int			i, s;
+	int			i;
 	u_char			eaddr[ETHER_ADDR_LEN];
 	u_int32_t		command;
 	struct vr_softc		*sc;
 	struct ifnet		*ifp;
 	int			unit, error = 0, rid;
 
-	s = splimp();
-
 	sc = device_get_softc(dev);
 	unit = device_get_unit(dev);
 	bzero(sc, sizeof(struct vr_softc *));
@@ -731,6 +729,8 @@ static int vr_attach(dev)
 		goto fail;
 	}
 
+	mtx_init(&sc->vr_mtx, "vr", MTX_DEF);
+	VR_LOCK(sc);
 	/* Reset the adapter. */
 	vr_reset(sc);
 
@@ -803,9 +803,13 @@ static int vr_attach(dev)
 	 * Call MI attach routine.
 	 */
 	ether_ifattach(ifp, ETHER_BPF_SUPPORTED);
+	VR_UNLOCK(sc);
+	return(0);
 
 fail:
-	splx(s);
+	VR_UNLOCK(sc);
+	mtx_destroy(&sc->vr_mtx);
+
 	return(error);
 }
 
@@ -814,11 +818,9 @@ static int vr_detach(dev)
 {
 	struct vr_softc		*sc;
 	struct ifnet		*ifp;
-	int			s;
-
-	s = splimp();
 
 	sc = device_get_softc(dev);
+	VR_LOCK(sc);
 	ifp = &sc->arpcom.ac_if;
 
 	vr_stop(sc);
@@ -833,7 +835,8 @@ static int vr_detach(dev)
 
 	contigfree(sc->vr_ldata, sizeof(struct vr_list_data), M_DEVBUF);
 
-	splx(s);
+	VR_UNLOCK(sc);
+	mtx_destroy(&sc->vr_mtx);
 
 	return(0);
 }
@@ -1146,17 +1149,15 @@ static void vr_tick(xsc)
 {
 	struct vr_softc		*sc;
 	struct mii_data		*mii;
-	int			s;
-
-	s = splimp();
 
 	sc = xsc;
+	VR_LOCK(sc);
 	mii = device_get_softc(sc->vr_miibus);
 	mii_tick(mii);
 
 	sc->vr_stat_ch = timeout(vr_tick, sc, hz);
 
-	splx(s);
+	VR_UNLOCK(sc);
 
 	return;
 }
@@ -1169,11 +1170,13 @@ static void vr_intr(arg)
 	u_int16_t		status;
 
 	sc = arg;
+	VR_LOCK(sc);
 	ifp = &sc->arpcom.ac_if;
 
 	/* Supress unwanted interrupts. */
 	if (!(ifp->if_flags & IFF_UP)) {
 		vr_stop(sc);
+		VR_UNLOCK(sc);
 		return;
 	}
 
@@ -1226,6 +1229,8 @@ static void vr_intr(arg)
 		vr_start(ifp);
 	}
 
+	VR_UNLOCK(sc);
+
 	return;
 }
 
@@ -1314,8 +1319,11 @@ static void vr_start(ifp)
 
 	sc = ifp->if_softc;
 
-	if (ifp->if_flags & IFF_OACTIVE)
+	VR_LOCK(sc);
+	if (ifp->if_flags & IFF_OACTIVE) {
+		VR_UNLOCK(sc);
 		return;
+	}
 
 	/*
 	 * Check for an available queue slot. If there are none,
@@ -1357,8 +1365,10 @@ static void vr_start(ifp)
 	/*
 	 * If there are no frames queued, bail.
 	 */
-	if (cur_tx == NULL)
+	if (cur_tx == NULL) {
+		VR_UNLOCK(sc);
 		return;
+	}
 
 	sc->vr_cdata.vr_tx_tail = cur_tx;
 
@@ -1369,6 +1379,7 @@ static void vr_start(ifp)
 	 * Set a timeout in case the chip goes out to lunch.
 	 */
 	ifp->if_timer = 5;
+	VR_UNLOCK(sc);
 
 	return;
 }
@@ -1379,9 +1390,8 @@ static void vr_init(xsc)
 	struct vr_softc		*sc = xsc;
 	struct ifnet		*ifp = &sc->arpcom.ac_if;
 	struct mii_data		*mii;
-	int			s;
 
-	s = splimp();
+	VR_LOCK(sc);
 
 	mii = device_get_softc(sc->vr_miibus);
 
@@ -1402,7 +1412,7 @@ static void vr_init(xsc)
 		printf("vr%d: initialization failed: no "
 			"memory for rx buffers\n", sc->vr_unit);
 		vr_stop(sc);
-		(void)splx(s);
+		VR_UNLOCK(sc);
 		return;
 	}
 
@@ -1451,10 +1461,10 @@ static void vr_init(xsc)
 	ifp->if_flags |= IFF_RUNNING;
 	ifp->if_flags &= ~IFF_OACTIVE;
 
-	(void)splx(s);
-
 	sc->vr_stat_ch = timeout(vr_tick, sc, hz);
 
+	VR_UNLOCK(sc);
+
 	return;
 }
 
@@ -1501,9 +1511,9 @@ static int vr_ioctl(ifp, command, data)
 	struct vr_softc		*sc = ifp->if_softc;
 	struct ifreq		*ifr = (struct ifreq *) data;
 	struct mii_data		*mii;
-	int			s, error = 0;
+	int			error = 0;
 
-	s = splimp();
+	VR_LOCK(sc);
 
 	switch(command) {
 	case SIOCSIFADDR:
@@ -1535,7 +1545,7 @@ static int vr_ioctl(ifp, command, data)
 		break;
 	}
 
-	(void)splx(s);
+	VR_UNLOCK(sc);
 
 	return(error);
 }
@@ -1547,6 +1557,7 @@ static void vr_watchdog(ifp)
 
 	sc = ifp->if_softc;
 
+	VR_LOCK(sc);
 	ifp->if_oerrors++;
 	printf("vr%d: watchdog timeout\n", sc->vr_unit);
 
@@ -1557,6 +1568,8 @@ static void vr_watchdog(ifp)
 	if (ifp->if_snd.ifq_head != NULL)
 		vr_start(ifp);
 
+	VR_UNLOCK(sc);
+
 	return;
 }
 
@@ -1570,6 +1583,8 @@ static void vr_stop(sc)
 	register int		i;
 	struct ifnet		*ifp;
 
+	VR_LOCK(sc);
+
 	ifp = &sc->arpcom.ac_if;
 	ifp->if_timer = 0;
 
@@ -1607,6 +1622,7 @@ static void vr_stop(sc)
 		sizeof(sc->vr_ldata->vr_tx_list));
 
 	ifp->if_flags &= ~(IFF_RUNNING | IFF_OACTIVE);
+	VR_UNLOCK(sc);
 
 	return;
 }
diff --git a/sys/dev/vr/if_vrreg.h b/sys/dev/vr/if_vrreg.h
index 2f2ac97..8217a8c 100644
--- a/sys/dev/vr/if_vrreg.h
+++ b/sys/dev/vr/if_vrreg.h
@@ -411,8 +411,12 @@ struct vr_softc {
 	struct vr_list_data	*vr_ldata;
 	struct vr_chain_data	vr_cdata;
 	struct callout_handle	vr_stat_ch;
+	struct mtx		vr_mtx;
 };
 
+#define	VR_LOCK(_sc)		mtx_enter(&(_sc)->vr_mtx, MTX_DEF)
+#define	VR_UNLOCK(_sc)		mtx_exit(&(_sc)->vr_mtx, MTX_DEF)
+
 /*
  * register space access macros
  */
diff --git a/sys/pci/if_dc.c b/sys/pci/if_dc.c
index 695b019..f7c97a1 100644
--- a/sys/pci/if_dc.c
+++ b/sys/pci/if_dc.c
@@ -109,6 +109,7 @@
 #include <machine/bus_memio.h>
 #include <machine/bus.h>
 #include <machine/resource.h>
+#include <machine/mutex.h>
 #include <sys/bus.h>
 #include <sys/rman.h>
 
@@ -555,9 +556,9 @@ static int dc_mii_readreg(sc, frame)
 	struct dc_mii_frame	*frame;
 	
 {
-	int			i, ack, s;
+	int			i, ack;
 
-	s = splimp();
+	DC_LOCK(sc);
 
 	/*
 	 * Set up frame for RX.
@@ -612,7 +613,7 @@ fail:
 	dc_mii_writebit(sc, 0);
 	dc_mii_writebit(sc, 0);
 
-	splx(s);
+	DC_UNLOCK(sc);
 
 	if (ack)
 		return(1);
@@ -627,9 +628,7 @@ static int dc_mii_writereg(sc, frame)
 	struct dc_mii_frame	*frame;
 	
 {
-	int			s;
-
-	s = splimp();
+	DC_LOCK(sc);
 	/*
 	 * Set up frame for TX.
 	 */
@@ -654,7 +653,7 @@ static int dc_mii_writereg(sc, frame)
 	dc_mii_writebit(sc, 0);
 	dc_mii_writebit(sc, 0);
 
-	splx(s);
+	DC_UNLOCK(sc);
 
 	return(0);
 }
@@ -1626,7 +1625,7 @@ static void dc_parse_21143_srom(sc)
 static int dc_attach(dev)
 	device_t		dev;
 {
-	int			s, tmp = 0;
+	int			tmp = 0;
 	u_char			eaddr[ETHER_ADDR_LEN];
 	u_int32_t		command;
 	struct dc_softc		*sc;
@@ -1634,8 +1633,6 @@ static int dc_attach(dev)
 	u_int32_t		revision;
 	int			unit, error = 0, rid, mac_offset;
 
-	s = splimp();
-
 	sc = device_get_softc(dev);
 	unit = device_get_unit(dev);
 	bzero(sc, sizeof(struct dc_softc));
@@ -1701,7 +1698,9 @@ static int dc_attach(dev)
 		printf("dc%d: couldn't set up irq\n", unit);
 		goto fail;
 	}
-	
+
+	mtx_init(&sc->dc_mtx, "dc", MTX_DEF);
+	DC_LOCK(sc);
 	/* Need this info to decide on a chip type. */
 	sc->dc_info = dc_devtype(dev);
 	revision = pci_read_config(dev, DC_PCI_CFRV, 4) & 0x000000FF;
@@ -1966,10 +1965,12 @@ static int dc_attach(dev)
 	}
 #endif
 
+	DC_UNLOCK(sc);
+	return(0);
 
 fail:
-	splx(s);
-
+	DC_UNLOCK(sc);
+	mtx_destroy(&sc->dc_mtx);
 	return(error);
 }
 
@@ -1978,12 +1979,12 @@ static int dc_detach(dev)
 {
 	struct dc_softc		*sc;
 	struct ifnet		*ifp;
-	int			s;
 	struct dc_mediainfo	*m;
 
-	s = splimp();
-
 	sc = device_get_softc(dev);
+
+	DC_LOCK(sc);
+
 	ifp = &sc->arpcom.ac_if;
 
 	dc_stop(sc);
@@ -2006,7 +2007,8 @@ static int dc_detach(dev)
 		sc->dc_mi = m;
 	}
 
-	splx(s);
+	DC_UNLOCK(sc);
+	mtx_destroy(&sc->dc_mtx);
 
 	return(0);
 }
@@ -2457,12 +2459,10 @@ static void dc_tick(xsc)
 	struct dc_softc		*sc;
 	struct mii_data		*mii;
 	struct ifnet		*ifp;
-	int			s;
 	u_int32_t		r;
 
-	s = splimp();
-
 	sc = xsc;
+	DC_LOCK(sc);
 	ifp = &sc->arpcom.ac_if;
 	mii = device_get_softc(sc->dc_miibus);
 
@@ -2526,7 +2526,7 @@ static void dc_tick(xsc)
 	else
 		sc->dc_stat_ch = timeout(dc_tick, sc, hz);
 
-	splx(s);
+	DC_UNLOCK(sc);
 
 	return;
 }
@@ -2539,12 +2539,14 @@ static void dc_intr(arg)
 	u_int32_t		status;
 
 	sc = arg;
+	DC_LOCK(sc);
 	ifp = &sc->arpcom.ac_if;
 
 	/* Supress unwanted interrupts */
 	if (!(ifp->if_flags & IFF_UP)) {
 		if (CSR_READ_4(sc, DC_ISR) & DC_INTRS)
 			dc_stop(sc);
+		DC_UNLOCK(sc);
 		return;
 	}
 
@@ -2621,6 +2623,8 @@ static void dc_intr(arg)
 	if (ifp->if_snd.ifq_head != NULL)
 		dc_start(ifp);
 
+	DC_UNLOCK(sc);
+
 	return;
 }
 
@@ -2737,11 +2741,17 @@ static void dc_start(ifp)
 
 	sc = ifp->if_softc;
 
-	if (!sc->dc_link)
+	DC_LOCK(sc);
+
+	if (!sc->dc_link) {
+		DC_UNLOCK(sc);
 		return;
+	}
 
-	if (ifp->if_flags & IFF_OACTIVE)
+	if (ifp->if_flags & IFF_OACTIVE) {
+		DC_UNLOCK(sc);
 		return;
+	}
 
 	idx = sc->dc_cdata.dc_tx_prod;
 
@@ -2787,6 +2797,8 @@ static void dc_start(ifp)
 	 */
 	ifp->if_timer = 5;
 
+	DC_UNLOCK(sc);
+
 	return;
 }
 
@@ -2796,9 +2808,8 @@ static void dc_init(xsc)
 	struct dc_softc		*sc = xsc;
 	struct ifnet		*ifp = &sc->arpcom.ac_if;
 	struct mii_data		*mii;
-	int			s;
 
-	s = splimp();
+	DC_LOCK(sc);
 
 	mii = device_get_softc(sc->dc_miibus);
 
@@ -2876,7 +2887,7 @@ static void dc_init(xsc)
 		printf("dc%d: initialization failed: no "
 		    "memory for rx buffers\n", sc->dc_unit);
 		dc_stop(sc);
-		(void)splx(s);
+		DC_UNLOCK(sc);
 		return;
 	}
 
@@ -2929,8 +2940,6 @@ static void dc_init(xsc)
 	ifp->if_flags |= IFF_RUNNING;
 	ifp->if_flags &= ~IFF_OACTIVE;
 
-	(void)splx(s);
-
 	/* Don't start the ticker if this is a homePNA link. */
 	if (IFM_SUBTYPE(mii->mii_media.ifm_media) == IFM_homePNA)
 		sc->dc_link = 1;
@@ -2950,6 +2959,7 @@ static void dc_init(xsc)
 		sc->dc_srm_media = 0;
 	}
 #endif
+	DC_UNLOCK(sc);
 	return;
 }
 
@@ -3013,9 +3023,9 @@ static int dc_ioctl(ifp, command, data)
 	struct dc_softc		*sc = ifp->if_softc;
 	struct ifreq		*ifr = (struct ifreq *) data;
 	struct mii_data		*mii;
-	int			s, error = 0;
+	int			error = 0;
 
-	s = splimp();
+	DC_LOCK(sc);
 
 	switch(command) {
 	case SIOCSIFADDR:
@@ -3063,7 +3073,7 @@ static int dc_ioctl(ifp, command, data)
 		break;
 	}
 
-	(void)splx(s);
+	DC_UNLOCK(sc);
 
 	return(error);
 }
@@ -3075,6 +3085,8 @@ static void dc_watchdog(ifp)
 
 	sc = ifp->if_softc;
 
+	DC_LOCK(sc);
+
 	ifp->if_oerrors++;
 	printf("dc%d: watchdog timeout\n", sc->dc_unit);
 
@@ -3085,6 +3097,8 @@ static void dc_watchdog(ifp)
 	if (ifp->if_snd.ifq_head != NULL)
 		dc_start(ifp);
 
+	DC_UNLOCK(sc);
+
 	return;
 }
 
@@ -3098,6 +3112,8 @@ static void dc_stop(sc)
 	register int		i;
 	struct ifnet		*ifp;
 
+	DC_LOCK(sc);
+
 	ifp = &sc->arpcom.ac_if;
 	ifp->if_timer = 0;
 
@@ -3141,6 +3157,8 @@ static void dc_stop(sc)
 
 	ifp->if_flags &= ~(IFF_RUNNING | IFF_OACTIVE);
 
+	DC_UNLOCK(sc);
+
 	return;
 }
 
diff --git a/sys/pci/if_dcreg.h b/sys/pci/if_dcreg.h
index 9c6cfc4..e72d8b4 100644
--- a/sys/pci/if_dcreg.h
+++ b/sys/pci/if_dcreg.h
@@ -676,8 +676,13 @@ struct dc_softc {
 #ifdef SRM_MEDIA
 	int			dc_srm_media;
 #endif
+	struct mtx		dc_mtx;
 };
 
+
+#define	DC_LOCK(_sc)		mtx_enter(&(_sc)->dc_mtx, MTX_DEF)
+#define	DC_UNLOCK(_sc)		mtx_exit(&(_sc)->dc_mtx, MTX_DEF)
+
 #define DC_TX_POLL		0x00000001
 #define DC_TX_COALESCE		0x00000002
 #define DC_TX_ADMTEK_WAR	0x00000004
diff --git a/sys/pci/if_pcn.c b/sys/pci/if_pcn.c
index 49241bd..9accefb 100644
--- a/sys/pci/if_pcn.c
+++ b/sys/pci/if_pcn.c
@@ -398,12 +398,16 @@ static int pcn_probe(dev)
 			}
 			sc->pcn_btag = rman_get_bustag(sc->pcn_res);
 			sc->pcn_bhandle = rman_get_bushandle(sc->pcn_res);
+			mtx_init(&sc->pcn_mtx, "pcn", MTX_DEF);
+			PCN_LOCK(sc);
 			pcn_reset(sc);
 			chip_id = pcn_csr_read(sc, PCN_CSR_CHIPID1);
 			chip_id <<= 16;
 			chip_id |= pcn_csr_read(sc, PCN_CSR_CHIPID0);
 			bus_release_resource(dev, PCN_RES,
 			    PCN_RID, sc->pcn_res);
+			PCN_UNLOCK(sc);
+			mtx_destroy(&sc->pcn_mtx);
 			chip_id >>= 12;
 			sc->pcn_type = chip_id & PART_MASK;
 			switch(sc->pcn_type) {
@@ -434,15 +438,12 @@ static int pcn_probe(dev)
 static int pcn_attach(dev)
 	device_t		dev;
 {
-	int			s;
 	u_int32_t		eaddr[2];
 	u_int32_t		command;
 	struct pcn_softc	*sc;
 	struct ifnet		*ifp;
 	int			unit, error = 0, rid;
 
-	s = splimp();
-
 	sc = device_get_softc(dev);
 	unit = device_get_unit(dev);
 
@@ -532,6 +533,10 @@ static int pcn_attach(dev)
 		goto fail;
 	}
 
+	/* Initialize our mutex. */
+	mtx_init(&sc->pcn_mtx, "pcn", MTX_DEF);
+	PCN_LOCK(sc);
+
 	/* Reset the adapter. */
 	pcn_reset(sc);
 
@@ -596,9 +601,13 @@ static int pcn_attach(dev)
 	 */
 	ether_ifattach(ifp, ETHER_BPF_SUPPORTED);
 	callout_handle_init(&sc->pcn_stat_ch);
+	PCN_UNLOCK(sc);
+	return(0);
 
 fail:
-	splx(s);
+	PCN_UNLOCK(sc);
+	mtx_destroy(&sc->pcn_mtx);
+
 	return(error);
 }
 
@@ -607,13 +616,12 @@ static int pcn_detach(dev)
 {
 	struct pcn_softc	*sc;
 	struct ifnet		*ifp;
-	int			s;
-
-	s = splimp();
 
 	sc = device_get_softc(dev);
 	ifp = &sc->arpcom.ac_if;
 
+	PCN_LOCK(sc);
+
 	pcn_reset(sc);
 	pcn_stop(sc);
 	ether_ifdetach(ifp, ETHER_BPF_SUPPORTED);
@@ -628,8 +636,9 @@ static int pcn_detach(dev)
 	bus_release_resource(dev, PCN_RES, PCN_RID, sc->pcn_res);
 
 	contigfree(sc->pcn_ldata, sizeof(struct pcn_list_data), M_DEVBUF);
+	PCN_UNLOCK(sc);
 
-	splx(s);
+	mtx_destroy(&sc->pcn_mtx);
 
 	return(0);
 }
@@ -860,12 +869,10 @@ static void pcn_tick(xsc)
 	struct pcn_softc	*sc;
 	struct mii_data		*mii;
 	struct ifnet		*ifp;
-	int			s;
-
-	s = splimp();
 
 	sc = xsc;
 	ifp = &sc->arpcom.ac_if;
+	PCN_LOCK(sc);
 
 	mii = device_get_softc(sc->pcn_miibus);
 	mii_tick(mii);
@@ -884,7 +891,7 @@ static void pcn_tick(xsc)
 
 	sc->pcn_stat_ch = timeout(pcn_tick, sc, hz);
 
-	splx(s);
+	PCN_UNLOCK(sc);
 
 	return;
 }
@@ -996,13 +1003,19 @@ static void pcn_start(ifp)
 
 	sc = ifp->if_softc;
 
-	if (!sc->pcn_link)
+	PCN_LOCK(sc);
+
+	if (!sc->pcn_link) {
+		PCN_UNLOCK(sc);
 		return;
+	}
 
 	idx = sc->pcn_cdata.pcn_tx_prod;
 
-	if (ifp->if_flags & IFF_OACTIVE)
+	if (ifp->if_flags & IFF_OACTIVE) {
+		PCN_UNLOCK(sc);
 		return;
+	}
 
 	while(sc->pcn_cdata.pcn_tx_chain[idx] == NULL) {
 		IF_DEQUEUE(&ifp->if_snd, m_head);
@@ -1033,6 +1046,8 @@ static void pcn_start(ifp)
 	 */
 	ifp->if_timer = 5;
 
+	PCN_UNLOCK(sc);
+
 	return;
 }
 
@@ -1042,9 +1057,8 @@ static void pcn_init(xsc)
 	struct pcn_softc	*sc = xsc;
 	struct ifnet		*ifp = &sc->arpcom.ac_if;
 	struct mii_data		*mii = NULL;
-	int			s;
 
-	s = splimp();
+	PCN_LOCK(sc);
 
 	/*
 	 * Cancel pending I/O and free all RX/TX buffers.
@@ -1067,7 +1081,7 @@ static void pcn_init(xsc)
 		printf("pcn%d: initialization failed: no "
 		    "memory for rx buffers\n", sc->pcn_unit);
 		pcn_stop(sc);
-		(void)splx(s);
+		PCN_UNLOCK(sc);
 		return;
 	}
 
@@ -1149,8 +1163,8 @@ static void pcn_init(xsc)
 	ifp->if_flags |= IFF_RUNNING;
 	ifp->if_flags &= ~IFF_OACTIVE;
 
-	(void)splx(s);
 	sc->pcn_stat_ch = timeout(pcn_tick, sc, hz);
+	PCN_UNLOCK(sc);
 
 	return;
 }
@@ -1207,9 +1221,9 @@ static int pcn_ioctl(ifp, command, data)
 	struct pcn_softc	*sc = ifp->if_softc;
 	struct ifreq		*ifr = (struct ifreq *) data;
 	struct mii_data		*mii = NULL;
-	int			s, error = 0;
+	int			error = 0;
 
-	s = splimp();
+	PCN_LOCK(sc);
 
 	switch(command) {
 	case SIOCSIFADDR:
@@ -1265,7 +1279,7 @@ static int pcn_ioctl(ifp, command, data)
 		break;
 	}
 
-	(void)splx(s);
+	PCN_UNLOCK(sc);
 
 	return(error);
 }
@@ -1277,6 +1291,8 @@ static void pcn_watchdog(ifp)
 
 	sc = ifp->if_softc;
 
+	PCN_LOCK(sc);
+
 	ifp->if_oerrors++;
 	printf("pcn%d: watchdog timeout\n", sc->pcn_unit);
 
@@ -1287,6 +1303,8 @@ static void pcn_watchdog(ifp)
 	if (ifp->if_snd.ifq_head != NULL)
 		pcn_start(ifp);
 
+	PCN_UNLOCK(sc);
+
 	return;
 }
 
@@ -1301,6 +1319,7 @@ static void pcn_stop(sc)
 	struct ifnet		*ifp;
 
 	ifp = &sc->arpcom.ac_if;
+	PCN_LOCK(sc);
 	ifp->if_timer = 0;
 
 	untimeout(pcn_tick, sc, sc->pcn_stat_ch);
@@ -1333,6 +1352,7 @@ static void pcn_stop(sc)
 		sizeof(sc->pcn_ldata->pcn_tx_list));
 
 	ifp->if_flags &= ~(IFF_RUNNING | IFF_OACTIVE);
+	PCN_UNLOCK(sc);
 
 	return;
 }
@@ -1348,8 +1368,10 @@ static void pcn_shutdown(dev)
 
 	sc = device_get_softc(dev);
 
+	PCN_LOCK(sc);
 	pcn_reset(sc);
 	pcn_stop(sc);
+	PCN_UNLOCK(sc);
 
 	return;
 }
diff --git a/sys/pci/if_pcnreg.h b/sys/pci/if_pcnreg.h
index 0ae5cf3..026c0ea 100644
--- a/sys/pci/if_pcnreg.h
+++ b/sys/pci/if_pcnreg.h
@@ -448,8 +448,12 @@ struct pcn_softc {
 	struct pcn_list_data	*pcn_ldata;
 	struct pcn_ring_data	pcn_cdata;
 	struct callout_handle	pcn_stat_ch;
+	struct mtx		pcn_mtx;
 };
 
+#define	PCN_LOCK(_sc)		mtx_enter(&(_sc)->pcn_mtx, MTX_DEF)
+#define	PCN_UNLOCK(_sc)		mtx_exit(&(_sc)->pcn_mtx, MTX_DEF)
+
 /*
  * register space access macros
  */
diff --git a/sys/pci/if_rl.c b/sys/pci/if_rl.c
index 78b80a2..010f612 100644
--- a/sys/pci/if_rl.c
+++ b/sys/pci/if_rl.c
@@ -401,9 +401,9 @@ static int rl_mii_readreg(sc, frame)
 	struct rl_mii_frame	*frame;
 	
 {
-	int			i, ack, s;
+	int			i, ack;
 
-	s = splimp();
+	RL_LOCK(sc);
 
 	/*
 	 * Set up frame for RX.
@@ -479,7 +479,7 @@ fail:
 	MII_SET(RL_MII_CLK);
 	DELAY(1);
 
-	splx(s);
+	RL_UNLOCK(sc);
 
 	if (ack)
 		return(1);
@@ -494,9 +494,8 @@ static int rl_mii_writereg(sc, frame)
 	struct rl_mii_frame	*frame;
 	
 {
-	int			s;
+	RL_LOCK(sc);
 
-	s = splimp();
 	/*
 	 * Set up frame for TX.
 	 */
@@ -530,7 +529,7 @@ static int rl_mii_writereg(sc, frame)
 	 */
 	MII_CLR(RL_MII_DIR);
 
-	splx(s);
+	RL_UNLOCK(sc);
 
 	return(0);
 }
@@ -545,11 +544,14 @@ static int rl_miibus_readreg(dev, phy, reg)
 	u_int16_t		rl8139_reg = 0;
 
 	sc = device_get_softc(dev);
+	RL_LOCK(sc);
 
 	if (sc->rl_type == RL_8139) {
 		/* Pretend the internal PHY is only at address 0 */
-		if (phy)
+		if (phy) {
+			RL_UNLOCK(sc);
 			return(0);
+		}
 		switch(reg) {
 		case MII_BMCR:
 			rl8139_reg = RL_BMCR;
@@ -568,13 +570,16 @@ static int rl_miibus_readreg(dev, phy, reg)
 			break;
 		case MII_PHYIDR1:
 		case MII_PHYIDR2:
+			RL_UNLOCK(sc);
 			return(0);
 			break;
 		default:
 			printf("rl%d: bad phy register\n", sc->rl_unit);
+			RL_UNLOCK(sc);
 			return(0);
 		}
 		rval = CSR_READ_2(sc, rl8139_reg);
+		RL_UNLOCK(sc);
 		return(rval);
 	}
 
@@ -583,6 +588,7 @@ static int rl_miibus_readreg(dev, phy, reg)
 	frame.mii_phyaddr = phy;
 	frame.mii_regaddr = reg;
 	rl_mii_readreg(sc, &frame);
+	RL_UNLOCK(sc);
 
 	return(frame.mii_data);
 }
@@ -596,11 +602,14 @@ static int rl_miibus_writereg(dev, phy, reg, data)
 	u_int16_t		rl8139_reg = 0;
 
 	sc = device_get_softc(dev);
+	RL_LOCK(sc);
 
 	if (sc->rl_type == RL_8139) {
 		/* Pretend the internal PHY is only at address 0 */
-		if (phy)
+		if (phy) {
+			RL_UNLOCK(sc);
 			return(0);
+		}
 		switch(reg) {
 		case MII_BMCR:
 			rl8139_reg = RL_BMCR;
@@ -619,13 +628,16 @@ static int rl_miibus_writereg(dev, phy, reg, data)
 			break;
 		case MII_PHYIDR1:
 		case MII_PHYIDR2:
+			RL_UNLOCK(sc);
 			return(0);
 			break;
 		default:
 			printf("rl%d: bad phy register\n", sc->rl_unit);
+			RL_UNLOCK(sc);
 			return(0);
 		}
 		CSR_WRITE_2(sc, rl8139_reg, data);
+		RL_UNLOCK(sc);
 		return(0);
 	}
 
@@ -637,6 +649,7 @@ static int rl_miibus_writereg(dev, phy, reg, data)
 
 	rl_mii_writereg(sc, &frame);
 
+	RL_UNLOCK(sc);
 	return(0);
 }
 
@@ -776,7 +789,6 @@ static int rl_probe(dev)
 static int rl_attach(dev)
 	device_t		dev;
 {
-	int			s;
 	u_char			eaddr[ETHER_ADDR_LEN];
 	u_int32_t		command;
 	struct rl_softc		*sc;
@@ -784,8 +796,6 @@ static int rl_attach(dev)
 	u_int16_t		rl_did = 0;
 	int			unit, error = 0, rid;
 
-	s = splimp();
-
 	sc = device_get_softc(dev);
 	unit = device_get_unit(dev);
 	bzero(sc, sizeof(struct rl_softc));
@@ -877,6 +887,9 @@ static int rl_attach(dev)
 
 	callout_handle_init(&sc->rl_stat_ch);
 
+	mtx_init(&sc->rl_mtx, "rl", MTX_DEF);
+	RL_LOCK(sc);
+
 	/* Reset the adapter. */
 	rl_reset(sc);
 
@@ -959,9 +972,12 @@ static int rl_attach(dev)
 	 * Call MI attach routine.
 	 */
 	ether_ifattach(ifp, ETHER_BPF_SUPPORTED);
+	RL_UNLOCK(sc);
+	return(0);
 
 fail:
-	splx(s);
+	RL_UNLOCK(sc);
+	mtx_destroy(&sc->rl_mtx);
 	return(error);
 }
 
@@ -970,11 +986,9 @@ static int rl_detach(dev)
 {
 	struct rl_softc		*sc;
 	struct ifnet		*ifp;
-	int			s;
-
-	s = splimp();
 
 	sc = device_get_softc(dev);
+	RL_LOCK(sc);
 	ifp = &sc->arpcom.ac_if;
 
 	ether_ifdetach(ifp, ETHER_BPF_SUPPORTED);
@@ -989,7 +1003,8 @@ static int rl_detach(dev)
 
 	contigfree(sc->rl_cdata.rl_rx_buf, RL_RXBUFLEN + 32, M_DEVBUF);
 
-	splx(s);
+	RL_UNLOCK(sc);
+	mtx_destroy(&sc->rl_mtx);
 
 	return(0);
 }
@@ -1231,18 +1246,15 @@ static void rl_tick(xsc)
 {
 	struct rl_softc		*sc;
 	struct mii_data		*mii;
-	int			s;
-
-	s = splimp();
 
 	sc = xsc;
+	RL_LOCK(sc);
 	mii = device_get_softc(sc->rl_miibus);
 
 	mii_tick(mii);
 
-	splx(s);
-
 	sc->rl_stat_ch = timeout(rl_tick, sc, hz);
+	RL_UNLOCK(sc);
 
 	return;
 }
@@ -1255,6 +1267,7 @@ static void rl_intr(arg)
 	u_int16_t		status;
 
 	sc = arg;
+	RL_LOCK(sc);
 	ifp = &sc->arpcom.ac_if;
 
 	/* Disable interrupts. */
@@ -1291,6 +1304,8 @@ static void rl_intr(arg)
 	if (ifp->if_snd.ifq_head != NULL)
 		rl_start(ifp);
 
+	RL_UNLOCK(sc);
+
 	return;
 }
 
@@ -1360,6 +1375,7 @@ static void rl_start(ifp)
 	struct mbuf		*m_head = NULL;
 
 	sc = ifp->if_softc;
+	RL_LOCK(sc);
 
 	while(RL_CUR_TXMBUF(sc) == NULL) {
 		IF_DEQUEUE(&ifp->if_snd, m_head);
@@ -1403,6 +1419,7 @@ static void rl_start(ifp)
 	 * Set a timeout in case the chip goes out to lunch.
 	 */
 	ifp->if_timer = 5;
+	RL_UNLOCK(sc);
 
 	return;
 }
@@ -1413,11 +1430,10 @@ static void rl_init(xsc)
 	struct rl_softc		*sc = xsc;
 	struct ifnet		*ifp = &sc->arpcom.ac_if;
 	struct mii_data		*mii;
-	int			s, i;
+	int			i;
 	u_int32_t		rxcfg = 0;
 
-	s = splimp();
-
+	RL_LOCK(sc);
 	mii = device_get_softc(sc->rl_miibus);
 
 	/*
@@ -1497,9 +1513,8 @@ static void rl_init(xsc)
 	ifp->if_flags |= IFF_RUNNING;
 	ifp->if_flags &= ~IFF_OACTIVE;
 
-	(void)splx(s);
-
 	sc->rl_stat_ch = timeout(rl_tick, sc, hz);
+	RL_UNLOCK(sc);
 
 	return;
 }
@@ -1548,9 +1563,9 @@ static int rl_ioctl(ifp, command, data)
 	struct rl_softc		*sc = ifp->if_softc;
 	struct ifreq		*ifr = (struct ifreq *) data;
 	struct mii_data		*mii;
-	int			s, error = 0;
+	int			error = 0;
 
-	s = splimp();
+	RL_LOCK(sc);
 
 	switch(command) {
 	case SIOCSIFADDR:
@@ -1582,7 +1597,7 @@ static int rl_ioctl(ifp, command, data)
 		break;
 	}
 
-	(void)splx(s);
+	RL_UNLOCK(sc);
 
 	return(error);
 }
@@ -1593,13 +1608,14 @@ static void rl_watchdog(ifp)
 	struct rl_softc		*sc;
 
 	sc = ifp->if_softc;
-
+	RL_LOCK(sc);
 	printf("rl%d: watchdog timeout\n", sc->rl_unit);
 	ifp->if_oerrors++;
 
 	rl_txeof(sc);
 	rl_rxeof(sc);
 	rl_init(sc);
+	RL_UNLOCK(sc);
 
 	return;
 }
@@ -1614,6 +1630,7 @@ static void rl_stop(sc)
 	register int		i;
 	struct ifnet		*ifp;
 
+	RL_LOCK(sc);
 	ifp = &sc->arpcom.ac_if;
 	ifp->if_timer = 0;
 
@@ -1634,7 +1651,7 @@ static void rl_stop(sc)
 	}
 
 	ifp->if_flags &= ~(IFF_RUNNING | IFF_OACTIVE);
-
+	RL_UNLOCK(sc);
 	return;
 }
 
diff --git a/sys/pci/if_rlreg.h b/sys/pci/if_rlreg.h
index 0bb9ffc..2f08768 100644
--- a/sys/pci/if_rlreg.h
+++ b/sys/pci/if_rlreg.h
@@ -368,8 +368,12 @@ struct rl_softc {
 	int			rl_txthresh;
 	struct rl_chain_data	rl_cdata;
 	struct callout_handle	rl_stat_ch;
+	struct mtx		rl_mtx;
 };
 
+#define	RL_LOCK(_sc)		mtx_enter(&(_sc)->rl_mtx, MTX_DEF)
+#define	RL_UNLOCK(_sc)		mtx_exit(&(_sc)->rl_mtx, MTX_DEF)
+
 /*
  * register space access macros
  */
diff --git a/sys/pci/if_sf.c b/sys/pci/if_sf.c
index 52c6f88..a7d14522 100644
--- a/sys/pci/if_sf.c
+++ b/sys/pci/if_sf.c
@@ -531,9 +531,9 @@ static int sf_ioctl(ifp, command, data)
 	struct sf_softc		*sc = ifp->if_softc;
 	struct ifreq		*ifr = (struct ifreq *) data;
 	struct mii_data		*mii;
-	int			s, error = 0;
+	int			error = 0;
 
-	s = splimp();
+	SF_LOCK(sc);
 
 	switch(command) {
 	case SIOCSIFADDR:
@@ -575,7 +575,7 @@ static int sf_ioctl(ifp, command, data)
 		break;
 	}
 
-	(void)splx(s);
+	SF_UNLOCK(sc);
 
 	return(error);
 }
@@ -670,14 +670,12 @@ static int sf_probe(dev)
 static int sf_attach(dev)
 	device_t		dev;
 {
-	int			s, i;
+	int			i;
 	u_int32_t		command;
 	struct sf_softc		*sc;
 	struct ifnet		*ifp;
 	int			unit, rid, error = 0;
 
-	s = splimp();
-
 	sc = device_get_softc(dev);
 	unit = device_get_unit(dev);
 	bzero(sc, sizeof(struct sf_softc));
@@ -768,7 +766,8 @@ static int sf_attach(dev)
 	}
 
 	callout_handle_init(&sc->sf_stat_ch);
-
+	mtx_init(&sc->sf_mtx, "sf", MTX_DEF);
+	SF_LOCK(sc);
 	/* Reset the adapter. */
 	sf_reset(sc);
 
@@ -832,9 +831,12 @@ static int sf_attach(dev)
 	 * Call MI attach routine.
 	 */
 	ether_ifattach(ifp, ETHER_BPF_SUPPORTED);
+	SF_UNLOCK(sc);
+	return(0);
 
 fail:
-	splx(s);
+	SF_UNLOCK(sc);
+	mtx_destroy(&sc->sf_mtx);
 	return(error);
 }
 
@@ -843,11 +845,9 @@ static int sf_detach(dev)
 {
 	struct sf_softc		*sc;
 	struct ifnet		*ifp;
-	int			s;
-
-	s = splimp();
 
 	sc = device_get_softc(dev);
+	SF_LOCK(sc);
 	ifp = &sc->arpcom.ac_if;
 
 	ether_ifdetach(ifp, ETHER_BPF_SUPPORTED);
@@ -862,7 +862,8 @@ static int sf_detach(dev)
 
 	contigfree(sc->sf_ldata, sizeof(struct sf_list_data), M_DEVBUF);
 
-	splx(s);
+	SF_UNLOCK(sc);
+	mtx_destroy(&sc->sf_mtx);
 
 	return(0);
 }
@@ -1086,10 +1087,14 @@ static void sf_intr(arg)
 	u_int32_t		status;
 
 	sc = arg;
+	SF_LOCK(sc);
+
 	ifp = &sc->arpcom.ac_if;
 
-	if (!(csr_read_4(sc, SF_ISR_SHADOW) & SF_ISR_PCIINT_ASSERTED))
+	if (!(csr_read_4(sc, SF_ISR_SHADOW) & SF_ISR_PCIINT_ASSERTED)) {
+		SF_UNLOCK(sc);
 		return;
+	}
 
 	/* Disable interrupts. */
 	csr_write_4(sc, SF_IMR, 0x00000000);
@@ -1124,6 +1129,7 @@ static void sf_intr(arg)
 	if (ifp->if_snd.ifq_head != NULL)
 		sf_start(ifp);
 
+	SF_UNLOCK(sc);
 	return;
 }
 
@@ -1133,11 +1139,10 @@ static void sf_init(xsc)
 	struct sf_softc		*sc;
 	struct ifnet		*ifp;
 	struct mii_data		*mii;
-	int			i, s;
-
-	s = splimp();
+	int			i;
 
 	sc = xsc;
+	SF_LOCK(sc);
 	ifp = &sc->arpcom.ac_if;
 	mii = device_get_softc(sc->sf_miibus);
 
@@ -1162,7 +1167,7 @@ static void sf_init(xsc)
 	if (sf_init_rx_ring(sc) == ENOBUFS) {
 		printf("sf%d: initialization failed: no "
 		    "memory for rx buffers\n", sc->sf_unit);
-		(void)splx(s);
+		SF_UNLOCK(sc);
 		return;
 	}
 
@@ -1237,7 +1242,7 @@ static void sf_init(xsc)
 
 	sc->sf_stat_ch = timeout(sf_stats_update, sc, hz);
 
-	splx(s);
+	SF_UNLOCK(sc);
 
 	return;
 }
@@ -1314,12 +1319,17 @@ static void sf_start(ifp)
 	int			i, txprod;
 
 	sc = ifp->if_softc;
+	SF_LOCK(sc);
 
-	if (!sc->sf_link)
+	if (!sc->sf_link) {
+		SF_UNLOCK(sc);
 		return;
+	}
 
-	if (ifp->if_flags & IFF_OACTIVE)
+	if (ifp->if_flags & IFF_OACTIVE) {
+		SF_UNLOCK(sc);
 		return;
+	}
 
 	txprod = csr_read_4(sc, SF_TXDQ_PRODIDX);
 	i = SF_IDX_HI(txprod) >> 4;
@@ -1345,8 +1355,10 @@ static void sf_start(ifp)
 			break;
 	}
 
-	if (cur_tx == NULL)
+	if (cur_tx == NULL) {
+		SF_UNLOCK(sc);
 		return;
+	}
 
 	/* Transmit */
 	csr_write_4(sc, SF_TXDQ_PRODIDX,
@@ -1355,6 +1367,8 @@ static void sf_start(ifp)
 
 	ifp->if_timer = 5;
 
+	SF_UNLOCK(sc);
+
 	return;
 }
 
@@ -1364,6 +1378,8 @@ static void sf_stop(sc)
 	int			i;
 	struct ifnet		*ifp;
 
+	SF_LOCK(sc);
+
 	ifp = &sc->arpcom.ac_if;
 
 	untimeout(sf_stats_update, sc, sc->sf_stat_ch);
@@ -1396,6 +1412,7 @@ static void sf_stop(sc)
 	}
 
 	ifp->if_flags &= ~(IFF_RUNNING|IFF_OACTIVE);
+	SF_UNLOCK(sc);
 
 	return;
 }
@@ -1415,11 +1432,10 @@ static void sf_stats_update(xsc)
 	struct mii_data		*mii;
 	struct sf_stats		stats;
 	u_int32_t		*ptr;
-	int			i, s;
-
-	s = splimp();
+	int			i;
 
 	sc = xsc;
+	SF_LOCK(sc);
 	ifp = &sc->arpcom.ac_if;
 	mii = device_get_softc(sc->sf_miibus);
 
@@ -1447,7 +1463,7 @@ static void sf_stats_update(xsc)
 
 	sc->sf_stat_ch = timeout(sf_stats_update, sc, hz);
 
-	splx(s);
+	SF_UNLOCK(sc);
 
 	return;
 }
@@ -1459,6 +1475,8 @@ static void sf_watchdog(ifp)
 
 	sc = ifp->if_softc;
 
+	SF_LOCK(sc);
+
 	ifp->if_oerrors++;
 	printf("sf%d: watchdog timeout\n", sc->sf_unit);
 
@@ -1469,6 +1487,8 @@ static void sf_watchdog(ifp)
 	if (ifp->if_snd.ifq_head != NULL)
 		sf_start(ifp);
 
+	SF_UNLOCK(sc);
+
 	return;
 }
 
diff --git a/sys/pci/if_sfreg.h b/sys/pci/if_sfreg.h
index 49fdd5a..c2dc20e 100644
--- a/sys/pci/if_sfreg.h
+++ b/sys/pci/if_sfreg.h
@@ -1044,8 +1044,13 @@ struct sf_softc {
 	u_int8_t		sf_link;
 	int			sf_if_flags;
 	struct callout_handle	sf_stat_ch;
+	struct mtx		sf_mtx;
 };
 
+
+#define	SF_LOCK(_sc)		mtx_enter(&(_sc)->sf_mtx, MTX_DEF)
+#define	SF_UNLOCK(_sc)		mtx_exit(&(_sc)->sf_mtx, MTX_DEF)
+
 #define SF_TIMEOUT	1000
 
 #ifdef __alpha__
diff --git a/sys/pci/if_sis.c b/sys/pci/if_sis.c
index cee8639..cca772c 100644
--- a/sys/pci/if_sis.c
+++ b/sys/pci/if_sis.c
@@ -629,15 +629,12 @@ static int sis_probe(dev)
 static int sis_attach(dev)
 	device_t		dev;
 {
-	int			s;
 	u_char			eaddr[ETHER_ADDR_LEN];
 	u_int32_t		command;
 	struct sis_softc	*sc;
 	struct ifnet		*ifp;
 	int			unit, error = 0, rid;
 
-	s = splimp();
-
 	sc = device_get_softc(dev);
 	unit = device_get_unit(dev);
 	bzero(sc, sizeof(struct sis_softc));
@@ -735,6 +732,9 @@ static int sis_attach(dev)
 		goto fail;
 	}
 
+	mtx_init(&sc->sis_mtx, "sis", MTX_DEF);
+	SIS_LOCK(sc);
+
 	/* Reset the adapter. */
 	sis_reset(sc);
 
@@ -837,9 +837,12 @@ static int sis_attach(dev)
 	 */
 	ether_ifattach(ifp, ETHER_BPF_SUPPORTED);
 	callout_handle_init(&sc->sis_stat_ch);
+	SIS_UNLOCK(sc);
+	return(0);
 
 fail:
-	splx(s);
+	SIS_UNLOCK(sc);
+	mtx_destroy(&sc->sis_mtx);
 	return(error);
 }
 
@@ -848,11 +851,10 @@ static int sis_detach(dev)
 {
 	struct sis_softc	*sc;
 	struct ifnet		*ifp;
-	int			s;
 
-	s = splimp();
 
 	sc = device_get_softc(dev);
+	SIS_LOCK(sc);
 	ifp = &sc->arpcom.ac_if;
 
 	sis_reset(sc);
@@ -868,7 +870,8 @@ static int sis_detach(dev)
 
 	contigfree(sc->sis_ldata, sizeof(struct sis_list_data), M_DEVBUF);
 
-	splx(s);
+	SIS_UNLOCK(sc);
+	mtx_destroy(&sc->sis_mtx);
 
 	return(0);
 }
@@ -1129,11 +1132,9 @@ static void sis_tick(xsc)
 	struct sis_softc	*sc;
 	struct mii_data		*mii;
 	struct ifnet		*ifp;
-	int			s;
-
-	s = splimp();
 
 	sc = xsc;
+	SIS_LOCK(sc);
 	ifp = &sc->arpcom.ac_if;
 
 	mii = device_get_softc(sc->sis_miibus);
@@ -1150,7 +1151,7 @@ static void sis_tick(xsc)
 
 	sc->sis_stat_ch = timeout(sis_tick, sc, hz);
 
-	splx(s);
+	SIS_UNLOCK(sc);
 
 	return;
 }
@@ -1163,11 +1164,13 @@ static void sis_intr(arg)
 	u_int32_t		status;
 
 	sc = arg;
+	SIS_LOCK(sc);
 	ifp = &sc->arpcom.ac_if;
 
 	/* Supress unwanted interrupts */
 	if (!(ifp->if_flags & IFF_UP)) {
 		sis_stop(sc);
+		SIS_UNLOCK(sc);
 		return;
 	}
 
@@ -1208,6 +1211,8 @@ static void sis_intr(arg)
 	if (ifp->if_snd.ifq_head != NULL)
 		sis_start(ifp);
 
+	SIS_UNLOCK(sc);
+
 	return;
 }
 
@@ -1275,14 +1280,19 @@ static void sis_start(ifp)
 	u_int32_t		idx;
 
 	sc = ifp->if_softc;
+	SIS_LOCK(sc);
 
-	if (!sc->sis_link)
+	if (!sc->sis_link) {
+		SIS_UNLOCK(sc);
 		return;
+	}
 
 	idx = sc->sis_cdata.sis_tx_prod;
 
-	if (ifp->if_flags & IFF_OACTIVE)
+	if (ifp->if_flags & IFF_OACTIVE) {
+		SIS_UNLOCK(sc);
 		return;
+	}
 
 	while(sc->sis_ldata->sis_tx_list[idx].sis_mbuf == NULL) {
 		IF_DEQUEUE(&ifp->if_snd, m_head);
@@ -1313,6 +1323,8 @@ static void sis_start(ifp)
 	 */
 	ifp->if_timer = 5;
 
+	SIS_UNLOCK(sc);
+
 	return;
 }
 
@@ -1322,9 +1334,8 @@ static void sis_init(xsc)
 	struct sis_softc	*sc = xsc;
 	struct ifnet		*ifp = &sc->arpcom.ac_if;
 	struct mii_data		*mii;
-	int			s;
 
-	s = splimp();
+	SIS_LOCK(sc);
 
 	/*
 	 * Cancel pending I/O and free all RX/TX buffers.
@@ -1361,7 +1372,7 @@ static void sis_init(xsc)
 		printf("sis%d: initialization failed: no "
 			"memory for rx buffers\n", sc->sis_unit);
 		sis_stop(sc);
-		(void)splx(s);
+		SIS_UNLOCK(sc);
 		return;
 	}
 
@@ -1469,10 +1480,10 @@ static void sis_init(xsc)
 	ifp->if_flags |= IFF_RUNNING;
 	ifp->if_flags &= ~IFF_OACTIVE;
 
-	(void)splx(s);
-
 	sc->sis_stat_ch = timeout(sis_tick, sc, hz);
 
+	SIS_UNLOCK(sc);
+
 	return;
 }
 
@@ -1528,9 +1539,9 @@ static int sis_ioctl(ifp, command, data)
 	struct sis_softc	*sc = ifp->if_softc;
 	struct ifreq		*ifr = (struct ifreq *) data;
 	struct mii_data		*mii;
-	int			s, error = 0;
+	int			error = 0;
 
-	s = splimp();
+	SIS_LOCK(sc);
 
 	switch(command) {
 	case SIOCSIFADDR:
@@ -1565,7 +1576,7 @@ static int sis_ioctl(ifp, command, data)
 		break;
 	}
 
-	(void)splx(s);
+	SIS_UNLOCK(sc);
 
 	return(error);
 }
@@ -1577,6 +1588,8 @@ static void sis_watchdog(ifp)
 
 	sc = ifp->if_softc;
 
+	SIS_LOCK(sc);
+
 	ifp->if_oerrors++;
 	printf("sis%d: watchdog timeout\n", sc->sis_unit);
 
@@ -1587,6 +1600,8 @@ static void sis_watchdog(ifp)
 	if (ifp->if_snd.ifq_head != NULL)
 		sis_start(ifp);
 
+	SIS_UNLOCK(sc);
+
 	return;
 }
 
@@ -1600,6 +1615,7 @@ static void sis_stop(sc)
 	register int		i;
 	struct ifnet		*ifp;
 
+	SIS_LOCK(sc);
 	ifp = &sc->arpcom.ac_if;
 	ifp->if_timer = 0;
 
@@ -1640,6 +1656,8 @@ static void sis_stop(sc)
 
 	ifp->if_flags &= ~(IFF_RUNNING | IFF_OACTIVE);
 
+	SIS_UNLOCK(sc);
+
 	return;
 }
 
@@ -1653,9 +1671,10 @@ static void sis_shutdown(dev)
 	struct sis_softc	*sc;
 
 	sc = device_get_softc(dev);
-
+	SIS_LOCK(sc);
 	sis_reset(sc);
 	sis_stop(sc);
+	SIS_UNLOCK(sc);
 
 	return;
 }
diff --git a/sys/pci/if_sisreg.h b/sys/pci/if_sisreg.h
index ee46c92..d1781b7 100644
--- a/sys/pci/if_sisreg.h
+++ b/sys/pci/if_sisreg.h
@@ -389,8 +389,12 @@ struct sis_softc {
 	struct sis_list_data	*sis_ldata;
 	struct sis_ring_data	sis_cdata;
 	struct callout_handle	sis_stat_ch;
+	struct mtx		sis_mtx;
 };
 
+#define	SIS_LOCK(_sc)		mtx_enter(&(_sc)->sis_mtx, MTX_DEF)
+#define	SIS_UNLOCK(_sc)		mtx_exit(&(_sc)->sis_mtx, MTX_DEF)
+
 /*
  * register space access macros
  */
diff --git a/sys/pci/if_sk.c b/sys/pci/if_sk.c
index a83a606..963f754 100644
--- a/sys/pci/if_sk.c
+++ b/sys/pci/if_sk.c
@@ -413,6 +413,8 @@ static int sk_miibus_readreg(dev, phy, reg)
 	if (sc_if->sk_phytype == SK_PHYTYPE_XMAC && phy != 0)
 		return(0);
 
+	SK_IF_LOCK(sc_if);
+
 	SK_XM_WRITE_2(sc_if, XM_PHY_ADDR, reg|(phy << 8));
 	SK_XM_READ_2(sc_if, XM_PHY_DATA);
 	if (sc_if->sk_phytype != SK_PHYTYPE_XMAC) {
@@ -430,7 +432,9 @@ static int sk_miibus_readreg(dev, phy, reg)
 		}
 	}
 	DELAY(1);
-	return(SK_XM_READ_2(sc_if, XM_PHY_DATA));
+	i = SK_XM_READ_2(sc_if, XM_PHY_DATA);
+	SK_IF_UNLOCK(sc_if);
+	return(i);
 }
 
 static int sk_miibus_writereg(dev, phy, reg, val)
@@ -441,6 +445,7 @@ static int sk_miibus_writereg(dev, phy, reg, val)
 	int			i;
 
 	sc_if = device_get_softc(dev);
+	SK_IF_LOCK(sc_if);
 
 	SK_XM_WRITE_2(sc_if, XM_PHY_ADDR, reg|(phy << 8));
 	for (i = 0; i < SK_TIMEOUT; i++) {
@@ -460,6 +465,8 @@ static int sk_miibus_writereg(dev, phy, reg, val)
 			break;
 	}
 
+	SK_IF_UNLOCK(sc_if);
+
 	if (i == SK_TIMEOUT)
 		printf("sk%d: phy write timed out\n", sc_if->sk_unit);
 
@@ -474,7 +481,7 @@ static void sk_miibus_statchg(dev)
 
 	sc_if = device_get_softc(dev);
 	mii = device_get_softc(sc_if->sk_miibus);
-
+	SK_IF_LOCK(sc_if);
 	/*
 	 * If this is a GMII PHY, manually set the XMAC's
 	 * duplex mode accordingly.
@@ -486,6 +493,7 @@ static void sk_miibus_statchg(dev)
 			SK_XM_CLRBIT_2(sc_if, XM_MMUCMD, XM_MMUCMD_GMIIFDX);
 		}
 	}
+	SK_IF_UNLOCK(sc_if);
 
 	return;
 }
@@ -872,10 +880,10 @@ static int sk_ioctl(ifp, command, data)
 {
 	struct sk_if_softc	*sc_if = ifp->if_softc;
 	struct ifreq		*ifr = (struct ifreq *) data;
-	int			s, error = 0;
+	int			error = 0;
 	struct mii_data		*mii;
 
-	s = splimp();
+	SK_IF_LOCK(sc_if);
 
 	switch(command) {
 	case SIOCSIFADDR:
@@ -928,7 +936,7 @@ static int sk_ioctl(ifp, command, data)
 		break;
 	}
 
-	(void)splx(s);
+	SK_IF_UNLOCK(sc_if);
 
 	return(error);
 }
@@ -1025,6 +1033,7 @@ static int sk_attach_xmac(dev)
 
 	sc_if = device_get_softc(dev);
 	sc = device_get_softc(device_get_parent(dev));
+	SK_LOCK(sc);
 	port = *(int *)device_get_ivars(dev);
 	free(device_get_ivars(dev), M_DEVBUF);
 	device_set_ivars(dev, NULL);
@@ -1113,6 +1122,7 @@ static int sk_attach_xmac(dev)
 	if (sc_if->sk_rdata == NULL) {
 		printf("sk%d: no memory for list buffers!\n", sc_if->sk_unit);
 		sc->sk_if[port] = NULL;
+		SK_UNLOCK(sc);
 		return(ENOMEM);
 	}
 
@@ -1125,6 +1135,7 @@ static int sk_attach_xmac(dev)
 		contigfree(sc_if->sk_rdata,
 		    sizeof(struct sk_ring_data), M_DEVBUF);
 		sc->sk_if[port] = NULL;
+		SK_UNLOCK(sc);
 		return(ENOMEM);
 	}
 
@@ -1151,6 +1162,7 @@ static int sk_attach_xmac(dev)
 		printf("skc%d: no PHY found!\n", sc_if->sk_unit);
 		contigfree(sc_if->sk_rdata,
 		    sizeof(struct sk_ring_data), M_DEVBUF);
+		SK_UNLOCK(sc);
 		return(ENXIO);
 	}
 
@@ -1160,6 +1172,8 @@ static int sk_attach_xmac(dev)
 	ether_ifattach(ifp, ETHER_BPF_SUPPORTED);
 	callout_handle_init(&sc_if->sk_tick_ch);
 
+	SK_UNLOCK(sc);
+
 	return(0);
 }
 
@@ -1170,13 +1184,10 @@ static int sk_attach_xmac(dev)
 static int sk_attach(dev)
 	device_t		dev;
 {
-	int			s;
 	u_int32_t		command;
 	struct sk_softc		*sc;
 	int			unit, error = 0, rid, *port;
 
-	s = splimp();
-
 	sc = device_get_softc(dev);
 	unit = device_get_unit(dev);
 	bzero(sc, sizeof(struct sk_softc));
@@ -1266,6 +1277,8 @@ static int sk_attach(dev)
 		goto fail;
 	}
 
+	mtx_init(&sc->sk_mtx, "skc", MTX_DEF);
+	SK_LOCK(sc);
 	/* Reset the adapter. */
 	sk_reset(sc);
 
@@ -1345,9 +1358,12 @@ static int sk_attach(dev)
 	CSR_WRITE_2(sc, SK_LED, SK_LED_GREEN_ON);
 
 	bus_generic_attach(dev);
+	SK_UNLOCK(sc);
+	return(0);
 
 fail:
-	splx(s);
+	SK_UNLOCK(sc);
+	mtx_destroy(&sc->sk_mtx);
 	return(error);
 }
 
@@ -1357,12 +1373,11 @@ static int sk_detach_xmac(dev)
 	struct sk_softc		*sc;
 	struct sk_if_softc	*sc_if;
 	struct ifnet		*ifp;
-	int			s;
-
-	s = splimp();
 
 	sc = device_get_softc(device_get_parent(dev));
 	sc_if = device_get_softc(dev);
+	SK_IF_LOCK(sc_if);
+
 	ifp = &sc_if->arpcom.ac_if;
 	sk_stop(sc_if);
 	ether_ifdetach(ifp, ETHER_BPF_SUPPORTED);
@@ -1371,6 +1386,7 @@ static int sk_detach_xmac(dev)
 		device_delete_child(dev, sc_if->sk_miibus);
 	contigfree(sc_if->sk_cdata.sk_jumbo_buf, SK_JMEM, M_DEVBUF);
 	contigfree(sc_if->sk_rdata, sizeof(struct sk_ring_data), M_DEVBUF);
+	SK_IF_UNLOCK(sc_if);
 
 	return(0);
 }
@@ -1379,11 +1395,9 @@ static int sk_detach(dev)
 	device_t		dev;
 {
 	struct sk_softc		*sc;
-	int			s;
-
-	s = splimp();
 
 	sc = device_get_softc(dev);
+	SK_LOCK(sc);
 
 	bus_generic_detach(dev);
 	if (sc->sk_devs[SK_PORT_A] != NULL)
@@ -1395,7 +1409,8 @@ static int sk_detach(dev)
 	bus_release_resource(dev, SYS_RES_IRQ, 0, sc->sk_irq);
 	bus_release_resource(dev, SK_RES, SK_RID, sc->sk_res);
 
-	splx(s);
+	SK_UNLOCK(sc);
+	mtx_destroy(&sc->sk_mtx);
 
 	return(0);
 }
@@ -1460,6 +1475,8 @@ static void sk_start(ifp)
 	sc_if = ifp->if_softc;
 	sc = sc_if->sk_softc;
 
+	SK_IF_LOCK(sc_if);
+
 	idx = sc_if->sk_cdata.sk_tx_prod;
 
 	while(sc_if->sk_cdata.sk_tx_chain[idx].sk_mbuf == NULL) {
@@ -1492,6 +1509,7 @@ static void sk_start(ifp)
 
 	/* Set a timeout in case the chip goes out to lunch. */
 	ifp->if_timer = 5;
+	SK_IF_UNLOCK(sc_if);
 
 	return;
 }
@@ -1516,6 +1534,7 @@ static void sk_shutdown(dev)
 	struct sk_softc		*sc;
 
 	sc = device_get_softc(dev);
+	SK_LOCK(sc);
 
 	/* Turn off the 'driver is loaded' LED. */
 	CSR_WRITE_2(sc, SK_LED, SK_LED_GREEN_OFF);
@@ -1525,6 +1544,7 @@ static void sk_shutdown(dev)
 	 * assert the resets on the attached XMAC(s).
 	 */
 	sk_reset(sc);
+	SK_UNLOCK(sc);
 
 	return;
 }
@@ -1644,14 +1664,18 @@ static void sk_tick(xsc_if)
 	int			i;
 
 	sc_if = xsc_if;
+	SK_IF_LOCK(sc_if);
 	ifp = &sc_if->arpcom.ac_if;
 	mii = device_get_softc(sc_if->sk_miibus);
 
-	if (!(ifp->if_flags & IFF_UP))
+	if (!(ifp->if_flags & IFF_UP)) {
+		SK_IF_UNLOCK(sc_if);
 		return;
+	}
 
 	if (sc_if->sk_phytype == SK_PHYTYPE_BCOM) {
 		sk_intr_bcom(sc_if);
+		SK_IF_UNLOCK(sc_if);
 		return;
 	}
 
@@ -1669,6 +1693,7 @@ static void sk_tick(xsc_if)
 
 	if (i != 3) {
 		sc_if->sk_tick_ch = timeout(sk_tick, sc_if, hz);
+		SK_IF_UNLOCK(sc_if);
 		return;
 	}
 
@@ -1679,6 +1704,7 @@ static void sk_tick(xsc_if)
 	mii_pollstat(mii);
 	untimeout(sk_tick, sc_if, sc_if->sk_tick_ch);
 
+	SK_IF_UNLOCK(sc_if);
 	return;
 }
 
@@ -1785,6 +1811,8 @@ static void sk_intr(xsc)
 	struct ifnet		*ifp0 = NULL, *ifp1 = NULL;
 	u_int32_t		status;
 
+	SK_LOCK(sc);
+
 	sc_if0 = sc->sk_if[SK_PORT_A];
 	sc_if1 = sc->sk_if[SK_PORT_B];
 
@@ -1846,6 +1874,8 @@ static void sk_intr(xsc)
 	if (ifp1 != NULL && ifp1->if_snd.ifq_head != NULL)
 		sk_start(ifp1);
 
+	SK_UNLOCK(sc);
+
 	return;
 }
 
@@ -2028,9 +2058,8 @@ static void sk_init(xsc)
 	struct sk_softc		*sc;
 	struct ifnet		*ifp;
 	struct mii_data		*mii;
-	int			s;
 
-	s = splimp();
+	SK_IF_LOCK(sc_if);
 
 	ifp = &sc_if->arpcom.ac_if;
 	sc = sc_if->sk_softc;
@@ -2100,7 +2129,7 @@ static void sk_init(xsc)
 		printf("sk%d: initialization failed: no "
 		    "memory for rx buffers\n", sc_if->sk_unit);
 		sk_stop(sc_if);
-		(void)splx(s);
+		SK_IF_UNLOCK(sc_if);
 		return;
 	}
 	sk_init_tx_ring(sc_if);
@@ -2126,7 +2155,7 @@ static void sk_init(xsc)
 	ifp->if_flags |= IFF_RUNNING;
 	ifp->if_flags &= ~IFF_OACTIVE;
 
-	splx(s);
+	SK_IF_UNLOCK(sc_if);
 
 	return;
 }
@@ -2138,6 +2167,7 @@ static void sk_stop(sc_if)
 	struct sk_softc		*sc;
 	struct ifnet		*ifp;
 
+	SK_IF_LOCK(sc_if);
 	sc = sc_if->sk_softc;
 	ifp = &sc_if->arpcom.ac_if;
 
@@ -2198,6 +2228,6 @@ static void sk_stop(sc_if)
 	}
 
 	ifp->if_flags &= ~(IFF_RUNNING|IFF_OACTIVE);
-
+	SK_IF_UNLOCK(sc_if);
 	return;
 }
diff --git a/sys/pci/if_skreg.h b/sys/pci/if_skreg.h
index 92a26be..6f31d1d 100644
--- a/sys/pci/if_skreg.h
+++ b/sys/pci/if_skreg.h
@@ -1179,8 +1179,14 @@ struct sk_softc {
 	u_int32_t		sk_intrmask;
 	struct sk_if_softc	*sk_if[2];
 	device_t		sk_devs[2];
+	struct mtx		sk_mtx;
 };
 
+#define	SK_LOCK(_sc)		mtx_enter(&(_sc)->sk_mtx, MTX_DEF)
+#define	SK_UNLOCK(_sc)		mtx_exit(&(_sc)->sk_mtx, MTX_DEF)
+#define	SK_IF_LOCK(_sc)		mtx_enter(&(_sc)->sk_softc->sk_mtx, MTX_DEF)
+#define	SK_IF_UNLOCK(_sc)	mtx_exit(&(_sc)->sk_softc->sk_mtx, MTX_DEF)
+
 /* Softc for each logical interface */
 struct sk_if_softc {
 	struct arpcom		arpcom;		/* interface info */
diff --git a/sys/pci/if_ti.c b/sys/pci/if_ti.c
index f1cfee5..04ec29d 100644
--- a/sys/pci/if_ti.c
+++ b/sys/pci/if_ti.c
@@ -1477,14 +1477,11 @@ static int ti_probe(dev)
 static int ti_attach(dev)
 	device_t		dev;
 {
-	int			s;
 	u_int32_t		command;
 	struct ifnet		*ifp;
 	struct ti_softc		*sc;
 	int			unit, error = 0, rid;
 
-	s = splimp();
-
 	sc = device_get_softc(dev);
 	unit = device_get_unit(dev);
 	bzero(sc, sizeof(struct ti_softc));
@@ -1540,6 +1537,9 @@ static int ti_attach(dev)
 		goto fail;
 	}
 
+	mtx_init(&sc->ti_mtx, "ti", MTX_DEF);
+	TI_LOCK(sc);
+
 	sc->ti_unit = unit;
 
 	if (ti_chipinit(sc)) {
@@ -1689,10 +1689,12 @@ static int ti_attach(dev)
 	 * Call MI attach routine.
 	 */
 	ether_ifattach(ifp, ETHER_BPF_SUPPORTED);
+	TI_UNLOCK(sc);
+	return(0);
 
 fail:
-	splx(s);
-
+	TI_UNLOCK(sc);
+	mtx_destroy(&sc->ti_mtx);
 	return(error);
 }
 
@@ -1701,11 +1703,10 @@ static int ti_detach(dev)
 {
 	struct ti_softc		*sc;
 	struct ifnet		*ifp;
-	int			s;
 
-	s = splimp();
 
 	sc = device_get_softc(dev);
+	TI_LOCK(sc);
 	ifp = &sc->arpcom.ac_if;
 
 	ether_ifdetach(ifp, ETHER_BPF_SUPPORTED);
@@ -1719,7 +1720,8 @@ static int ti_detach(dev)
 	contigfree(sc->ti_rdata, sizeof(struct ti_ring_data), M_DEVBUF);
 	ifmedia_removeall(&sc->ifmedia);
 
-	splx(s);
+	TI_UNLOCK(sc);
+	mtx_destroy(&sc->ti_mtx);
 
 	return(0);
 }
@@ -1907,13 +1909,16 @@ static void ti_intr(xsc)
 	struct ifnet		*ifp;
 
 	sc = xsc;
+	TI_LOCK(sc);
 	ifp = &sc->arpcom.ac_if;
 
 #ifdef notdef
 	/* Avoid this for now -- checking this register is expensive. */
 	/* Make sure this is really our interrupt. */
-	if (!(CSR_READ_4(sc, TI_MISC_HOST_CTL) & TI_MHC_INTSTATE))
+	if (!(CSR_READ_4(sc, TI_MISC_HOST_CTL) & TI_MHC_INTSTATE)) {
+		TI_UNLOCK(sc);
 		return;
+	}
 #endif
 
 	/* Ack interrupt and stop others from occuring. */
@@ -1935,6 +1940,8 @@ static void ti_intr(xsc)
 	if (ifp->if_flags & IFF_RUNNING && ifp->if_snd.ifq_head != NULL)
 		ti_start(ifp);
 
+	TI_UNLOCK(sc);
+
 	return;
 }
 
@@ -2069,6 +2076,7 @@ static void ti_start(ifp)
 	u_int32_t		prodidx = 0;
 
 	sc = ifp->if_softc;
+	TI_LOCK(sc);
 
 	prodidx = CSR_READ_4(sc, TI_MB_SENDPROD_IDX);
 
@@ -2121,6 +2129,7 @@ static void ti_start(ifp)
 	 * Set a timeout in case the chip goes out to lunch.
 	 */
 	ifp->if_timer = 5;
+	TI_UNLOCK(sc);
 
 	return;
 }
@@ -2129,21 +2138,19 @@ static void ti_init(xsc)
 	void			*xsc;
 {
 	struct ti_softc		*sc = xsc;
-        int			s;
-
-	s = splimp();
 
 	/* Cancel pending I/O and flush buffers. */
 	ti_stop(sc);
 
+	TI_LOCK(sc);
 	/* Init the gen info block, ring control blocks and firmware. */
 	if (ti_gibinit(sc)) {
 		printf("ti%d: initialization failure\n", sc->ti_unit);
-		splx(s);
+		TI_UNLOCK(sc);
 		return;
 	}
 
-	splx(s);
+	TI_UNLOCK(sc);
 
 	return;
 }
@@ -2355,10 +2362,10 @@ static int ti_ioctl(ifp, command, data)
 {
 	struct ti_softc		*sc = ifp->if_softc;
 	struct ifreq		*ifr = (struct ifreq *) data;
-	int			s, error = 0;
+	int			error = 0;
 	struct ti_cmd_desc	cmd;
 
-	s = splimp();
+	TI_LOCK(sc);
 
 	switch(command) {
 	case SIOCSIFADDR:
@@ -2419,7 +2426,7 @@ static int ti_ioctl(ifp, command, data)
 		break;
 	}
 
-	(void)splx(s);
+	TI_UNLOCK(sc);
 
 	return(error);
 }
@@ -2430,12 +2437,14 @@ static void ti_watchdog(ifp)
 	struct ti_softc		*sc;
 
 	sc = ifp->if_softc;
+	TI_LOCK(sc);
 
 	printf("ti%d: watchdog timeout -- resetting\n", sc->ti_unit);
 	ti_stop(sc);
 	ti_init(sc);
 
 	ifp->if_oerrors++;
+	TI_UNLOCK(sc);
 
 	return;
 }
@@ -2450,6 +2459,8 @@ static void ti_stop(sc)
 	struct ifnet		*ifp;
 	struct ti_cmd_desc	cmd;
 
+	TI_LOCK(sc);
+
 	ifp = &sc->arpcom.ac_if;
 
 	/* Disable host interrupts. */
@@ -2482,6 +2493,7 @@ static void ti_stop(sc)
 	sc->ti_tx_saved_considx = TI_TXCONS_UNSET;
 
 	ifp->if_flags &= ~(IFF_RUNNING | IFF_OACTIVE);
+	TI_UNLOCK(sc);
 
 	return;
 }
@@ -2496,8 +2508,9 @@ static void ti_shutdown(dev)
 	struct ti_softc		*sc;
 
 	sc = device_get_softc(dev);
-
+	TI_LOCK(sc);
 	ti_chipinit(sc);
+	TI_UNLOCK(sc);
 
 	return;
 }
diff --git a/sys/pci/if_tireg.h b/sys/pci/if_tireg.h
index 6346c67..d64cc7a 100644
--- a/sys/pci/if_tireg.h
+++ b/sys/pci/if_tireg.h
@@ -1148,8 +1148,12 @@ struct ti_softc {
 	u_int32_t		ti_tx_buf_ratio;
 	int			ti_if_flags;
 	int			ti_txcnt;
+	struct mtx		ti_mtx;
 };
 
+#define	TI_LOCK(_sc)		mtx_enter(&(_sc)->ti_mtx, MTX_DEF)
+#define	TI_UNLOCK(_sc)		mtx_exit(&(_sc)->ti_mtx, MTX_DEF)
+
 /*
  * Microchip Technology 24Cxx EEPROM control bytes
  */
diff --git a/sys/pci/if_tl.c b/sys/pci/if_tl.c
index a18ac22..0d5a286 100644
--- a/sys/pci/if_tl.c
+++ b/sys/pci/if_tl.c
@@ -648,10 +648,10 @@ static int tl_mii_readreg(sc, frame)
 	struct tl_mii_frame	*frame;
 	
 {
-	int			i, ack, s;
+	int			i, ack;
 	int			minten = 0;
 
-	s = splimp();
+	TL_LOCK(sc);
 
 	tl_mii_sync(sc);
 
@@ -731,7 +731,7 @@ fail:
 		tl_dio_setbit(sc, TL_NETSIO, TL_SIO_MINTEN);
 	}
 
-	splx(s);
+	TL_UNLOCK(sc);
 
 	if (ack)
 		return(1);
@@ -743,12 +743,12 @@ static int tl_mii_writereg(sc, frame)
 	struct tl_mii_frame	*frame;
 	
 {
-	int			s;
 	int			minten;
 
+	TL_LOCK(sc);
+
 	tl_mii_sync(sc);
 
-	s = splimp();
 	/*
 	 * Set up frame for TX.
 	 */
@@ -789,7 +789,7 @@ static int tl_mii_writereg(sc, frame)
 	if (minten)
 		tl_dio_setbit(sc, TL_NETSIO, TL_SIO_MINTEN);
 
-	splx(s);
+	TL_UNLOCK(sc);
 
 	return(0);
 }
@@ -837,6 +837,7 @@ static void tl_miibus_statchg(dev)
 	struct mii_data		*mii;
 
 	sc = device_get_softc(dev);
+	TL_LOCK(sc);
 	mii = device_get_softc(sc->tl_miibus);
 
 	if ((mii->mii_media_active & IFM_GMASK) == IFM_FDX) {
@@ -844,6 +845,7 @@ static void tl_miibus_statchg(dev)
 	} else {
 		tl_dio_clrbit(sc, TL_NETCMD, TL_CMD_DUPLEX);
 	}
+	TL_UNLOCK(sc);
 
 	return;
 }
@@ -1105,7 +1107,7 @@ static int tl_probe(dev)
 static int tl_attach(dev)
 	device_t		dev;
 {
-	int			s, i;
+	int			i;
 	u_int32_t		command;
 	u_int16_t		did, vid;
 	struct tl_type		*t;
@@ -1113,8 +1115,6 @@ static int tl_attach(dev)
 	struct tl_softc		*sc;
 	int			unit, error = 0, rid;
 
-	s = splimp();
-
 	vid = pci_get_vendor(dev);
 	did = pci_get_device(dev);
 	sc = device_get_softc(dev);
@@ -1245,6 +1245,9 @@ static int tl_attach(dev)
 	if (t->tl_vid == OLICOM_VENDORID)
 		sc->tl_eeaddr = TL_EEPROM_EADDR_OC;
 
+	mtx_init(&sc->tl_mtx, "tl", MTX_DEF);
+	TL_LOCK(sc);
+
 	/* Reset the adapter. */
 	tl_softreset(sc, 1);
 	tl_hardreset(dev);
@@ -1338,9 +1341,12 @@ static int tl_attach(dev)
 	 * Call MI attach routine.
 	 */
 	ether_ifattach(ifp, ETHER_BPF_SUPPORTED);
+	TL_UNLOCK(sc);
+	return(0);
 
 fail:
-	splx(s);
+	TL_UNLOCK(sc);
+	mtx_destroy(&sc->tl_mtx);
 	return(error);
 }
 
@@ -1349,11 +1355,9 @@ static int tl_detach(dev)
 {
 	struct tl_softc		*sc;
 	struct ifnet		*ifp;
-	int			s;
-
-	s = splimp();
 
 	sc = device_get_softc(dev);
+	TL_LOCK(sc);
 	ifp = &sc->arpcom.ac_if;
 
 	tl_stop(sc);
@@ -1370,7 +1374,8 @@ static int tl_detach(dev)
 	bus_release_resource(dev, SYS_RES_IRQ, 0, sc->tl_irq);
 	bus_release_resource(dev, TL_RES, TL_RID, sc->tl_res);
 
-	splx(s);
+	TL_UNLOCK(sc);
+	mtx_destroy(&sc->tl_mtx);
 
 	return(0);
 }
@@ -1722,6 +1727,7 @@ static void tl_intr(xsc)
 	u_int8_t		ivec = 0;
 
 	sc = xsc;
+	TL_LOCK(sc);
 
 	/* Disable interrupts */
 	ints = CSR_READ_2(sc, TL_HOST_INT);
@@ -1780,6 +1786,8 @@ static void tl_intr(xsc)
 	if (ifp->if_snd.ifq_head != NULL)
 		tl_start(ifp);
 
+	TL_UNLOCK(sc);
+
 	return;
 }
 
@@ -1791,13 +1799,11 @@ static void tl_stats_update(xsc)
 	struct tl_stats		tl_stats;
 	struct mii_data		*mii;
 	u_int32_t		*p;
-	int			s;
-
-	s = splimp();
 
 	bzero((char *)&tl_stats, sizeof(struct tl_stats));
 
 	sc = xsc;
+	TL_LOCK(sc);
 	ifp = &sc->arpcom.ac_if;
 
 	p = (u_int32_t *)&tl_stats;
@@ -1838,7 +1844,7 @@ static void tl_stats_update(xsc)
 		mii_tick(mii);
 	}
 
-	splx(s);
+	TL_UNLOCK(sc);
 
 	return;
 }
@@ -1953,6 +1959,7 @@ static void tl_start(ifp)
 	struct tl_chain		*prev = NULL, *cur_tx = NULL, *start_tx;
 
 	sc = ifp->if_softc;
+	TL_LOCK(sc);
 
 	/*
 	 * Check for an available queue slot. If there are none,
@@ -1960,6 +1967,7 @@ static void tl_start(ifp)
 	 */
 	if (sc->tl_cdata.tl_tx_free == NULL) {
 		ifp->if_flags |= IFF_OACTIVE;
+		TL_UNLOCK(sc);
 		return;
 	}
 
@@ -1997,8 +2005,10 @@ static void tl_start(ifp)
 	/*
 	 * If there are no packets queued, bail.
 	 */
-	if (cur_tx == NULL)
+	if (cur_tx == NULL) {
+		TL_UNLOCK(sc);
 		return;
+	}
 
 	/*
 	 * That's all we can stands, we can't stands no more.
@@ -2028,6 +2038,7 @@ static void tl_start(ifp)
 	 * Set a timeout in case the chip goes out to lunch.
 	 */
 	ifp->if_timer = 5;
+	TL_UNLOCK(sc);
 
 	return;
 }
@@ -2037,10 +2048,9 @@ static void tl_init(xsc)
 {
 	struct tl_softc		*sc = xsc;
 	struct ifnet		*ifp = &sc->arpcom.ac_if;
-        int			s;
 	struct mii_data		*mii;
 
-	s = splimp();
+	TL_LOCK(sc);
 
 	ifp = &sc->arpcom.ac_if;
 
@@ -2085,6 +2095,7 @@ static void tl_init(xsc)
 		printf("tl%d: initialization failed: no "
 			"memory for rx buffers\n", sc->tl_unit);
 		tl_stop(sc);
+		TL_UNLOCK(sc);
 		return;
 	}
 
@@ -2111,10 +2122,9 @@ static void tl_init(xsc)
 	ifp->if_flags |= IFF_RUNNING;
 	ifp->if_flags &= ~IFF_OACTIVE;
 
-	(void)splx(s);
-
 	/* Start the stats update counter */
 	sc->tl_stat_ch = timeout(tl_stats_update, sc, hz);
+	TL_UNLOCK(sc);
 
 	return;
 }
@@ -2266,6 +2276,8 @@ static void tl_stop(sc)
 	register int		i;
 	struct ifnet		*ifp;
 
+	TL_LOCK(sc);
+
 	ifp = &sc->arpcom.ac_if;
 
 	/* Stop the stats updater. */
@@ -2316,6 +2328,7 @@ static void tl_stop(sc)
 		sizeof(sc->tl_ldata->tl_tx_list));
 
 	ifp->if_flags &= ~(IFF_RUNNING | IFF_OACTIVE);
+	TL_UNLOCK(sc);
 
 	return;
 }
diff --git a/sys/pci/if_tlreg.h b/sys/pci/if_tlreg.h
index 29c7e62..eb57a2c 100644
--- a/sys/pci/if_tlreg.h
+++ b/sys/pci/if_tlreg.h
@@ -126,8 +126,12 @@ struct tl_softc {
 	u_int8_t		tl_bitrate;
 	int			tl_if_flags;
 	struct callout_handle	tl_stat_ch;
+	struct mtx		tl_mtx;
 };
 
+#define	TL_LOCK(_sc)		mtx_enter(&(_sc)->tl_mtx, MTX_DEF)
+#define	TL_UNLOCK(_sc)		mtx_exit(&(_sc)->tl_mtx, MTX_DEF)
+
 /*
  * Transmit interrupt threshold.
  */
diff --git a/sys/pci/if_vr.c b/sys/pci/if_vr.c
index 3649d7e..10b9942 100644
--- a/sys/pci/if_vr.c
+++ b/sys/pci/if_vr.c
@@ -285,9 +285,9 @@ static int vr_mii_readreg(sc, frame)
 	struct vr_mii_frame	*frame;
 	
 {
-	int			i, ack, s;
+	int			i, ack;
 
-	s = splimp();
+	VR_LOCK(sc);
 
 	/*
 	 * Set up frame for RX.
@@ -364,7 +364,7 @@ fail:
 	SIO_SET(VR_MIICMD_CLK);
 	DELAY(1);
 
-	splx(s);
+	VR_UNLOCK(sc);
 
 	if (ack)
 		return(1);
@@ -379,9 +379,7 @@ static int vr_mii_writereg(sc, frame)
 	struct vr_mii_frame	*frame;
 	
 {
-	int			s;
-
-	s = splimp();
+	VR_LOCK(sc);
 
 	CSR_WRITE_1(sc, VR_MIICMD, 0);
 	VR_SETBIT(sc, VR_MIICMD, VR_MIICMD_DIRECTPGM);
@@ -419,7 +417,7 @@ static int vr_mii_writereg(sc, frame)
 	 */
 	SIO_CLR(VR_MIICMD_DIR);
 
-	splx(s);
+	VR_UNLOCK(sc);
 
 	return(0);
 }
@@ -467,8 +465,10 @@ static void vr_miibus_statchg(dev)
 	struct mii_data		*mii;
 
 	sc = device_get_softc(dev);
+	VR_LOCK(sc);
 	mii = device_get_softc(sc->vr_miibus);
 	vr_setcfg(sc, mii->mii_media_active);
+	VR_UNLOCK(sc);
 
 	return;
 }
@@ -633,15 +633,13 @@ static int vr_probe(dev)
 static int vr_attach(dev)
 	device_t		dev;
 {
-	int			i, s;
+	int			i;
 	u_char			eaddr[ETHER_ADDR_LEN];
 	u_int32_t		command;
 	struct vr_softc		*sc;
 	struct ifnet		*ifp;
 	int			unit, error = 0, rid;
 
-	s = splimp();
-
 	sc = device_get_softc(dev);
 	unit = device_get_unit(dev);
 	bzero(sc, sizeof(struct vr_softc *));
@@ -731,6 +729,8 @@ static int vr_attach(dev)
 		goto fail;
 	}
 
+	mtx_init(&sc->vr_mtx, "vr", MTX_DEF);
+	VR_LOCK(sc);
 	/* Reset the adapter. */
 	vr_reset(sc);
 
@@ -803,9 +803,13 @@ static int vr_attach(dev)
 	 * Call MI attach routine.
 	 */
 	ether_ifattach(ifp, ETHER_BPF_SUPPORTED);
+	VR_UNLOCK(sc);
+	return(0);
 
 fail:
-	splx(s);
+	VR_UNLOCK(sc);
+	mtx_destroy(&sc->vr_mtx);
+
 	return(error);
 }
 
@@ -814,11 +818,9 @@ static int vr_detach(dev)
 {
 	struct vr_softc		*sc;
 	struct ifnet		*ifp;
-	int			s;
-
-	s = splimp();
 
 	sc = device_get_softc(dev);
+	VR_LOCK(sc);
 	ifp = &sc->arpcom.ac_if;
 
 	vr_stop(sc);
@@ -833,7 +835,8 @@ static int vr_detach(dev)
 
 	contigfree(sc->vr_ldata, sizeof(struct vr_list_data), M_DEVBUF);
 
-	splx(s);
+	VR_UNLOCK(sc);
+	mtx_destroy(&sc->vr_mtx);
 
 	return(0);
 }
@@ -1146,17 +1149,15 @@ static void vr_tick(xsc)
 {
 	struct vr_softc		*sc;
 	struct mii_data		*mii;
-	int			s;
-
-	s = splimp();
 
 	sc = xsc;
+	VR_LOCK(sc);
 	mii = device_get_softc(sc->vr_miibus);
 	mii_tick(mii);
 
 	sc->vr_stat_ch = timeout(vr_tick, sc, hz);
 
-	splx(s);
+	VR_UNLOCK(sc);
 
 	return;
 }
@@ -1169,11 +1170,13 @@ static void vr_intr(arg)
 	u_int16_t		status;
 
 	sc = arg;
+	VR_LOCK(sc);
 	ifp = &sc->arpcom.ac_if;
 
 	/* Supress unwanted interrupts. */
 	if (!(ifp->if_flags & IFF_UP)) {
 		vr_stop(sc);
+		VR_UNLOCK(sc);
 		return;
 	}
 
@@ -1226,6 +1229,8 @@ static void vr_intr(arg)
 		vr_start(ifp);
 	}
 
+	VR_UNLOCK(sc);
+
 	return;
 }
 
@@ -1314,8 +1319,11 @@ static void vr_start(ifp)
 
 	sc = ifp->if_softc;
 
-	if (ifp->if_flags & IFF_OACTIVE)
+	VR_LOCK(sc);
+	if (ifp->if_flags & IFF_OACTIVE) {
+		VR_UNLOCK(sc);
 		return;
+	}
 
 	/*
 	 * Check for an available queue slot. If there are none,
@@ -1357,8 +1365,10 @@ static void vr_start(ifp)
 	/*
 	 * If there are no frames queued, bail.
 	 */
-	if (cur_tx == NULL)
+	if (cur_tx == NULL) {
+		VR_UNLOCK(sc);
 		return;
+	}
 
 	sc->vr_cdata.vr_tx_tail = cur_tx;
 
@@ -1369,6 +1379,7 @@ static void vr_start(ifp)
 	 * Set a timeout in case the chip goes out to lunch.
 	 */
 	ifp->if_timer = 5;
+	VR_UNLOCK(sc);
 
 	return;
 }
@@ -1379,9 +1390,8 @@ static void vr_init(xsc)
 	struct vr_softc		*sc = xsc;
 	struct ifnet		*ifp = &sc->arpcom.ac_if;
 	struct mii_data		*mii;
-	int			s;
 
-	s = splimp();
+	VR_LOCK(sc);
 
 	mii = device_get_softc(sc->vr_miibus);
 
@@ -1402,7 +1412,7 @@ static void vr_init(xsc)
 		printf("vr%d: initialization failed: no "
 			"memory for rx buffers\n", sc->vr_unit);
 		vr_stop(sc);
-		(void)splx(s);
+		VR_UNLOCK(sc);
 		return;
 	}
 
@@ -1451,10 +1461,10 @@ static void vr_init(xsc)
 	ifp->if_flags |= IFF_RUNNING;
 	ifp->if_flags &= ~IFF_OACTIVE;
 
-	(void)splx(s);
-
 	sc->vr_stat_ch = timeout(vr_tick, sc, hz);
 
+	VR_UNLOCK(sc);
+
 	return;
 }
 
@@ -1501,9 +1511,9 @@ static int vr_ioctl(ifp, command, data)
 	struct vr_softc		*sc = ifp->if_softc;
 	struct ifreq		*ifr = (struct ifreq *) data;
 	struct mii_data		*mii;
-	int			s, error = 0;
+	int			error = 0;
 
-	s = splimp();
+	VR_LOCK(sc);
 
 	switch(command) {
 	case SIOCSIFADDR:
@@ -1535,7 +1545,7 @@ static int vr_ioctl(ifp, command, data)
 		break;
 	}
 
-	(void)splx(s);
+	VR_UNLOCK(sc);
 
 	return(error);
 }
@@ -1547,6 +1557,7 @@ static void vr_watchdog(ifp)
 
 	sc = ifp->if_softc;
 
+	VR_LOCK(sc);
 	ifp->if_oerrors++;
 	printf("vr%d: watchdog timeout\n", sc->vr_unit);
 
@@ -1557,6 +1568,8 @@ static void vr_watchdog(ifp)
 	if (ifp->if_snd.ifq_head != NULL)
 		vr_start(ifp);
 
+	VR_UNLOCK(sc);
+
 	return;
 }
 
@@ -1570,6 +1583,8 @@ static void vr_stop(sc)
 	register int		i;
 	struct ifnet		*ifp;
 
+	VR_LOCK(sc);
+
 	ifp = &sc->arpcom.ac_if;
 	ifp->if_timer = 0;
 
@@ -1607,6 +1622,7 @@ static void vr_stop(sc)
 		sizeof(sc->vr_ldata->vr_tx_list));
 
 	ifp->if_flags &= ~(IFF_RUNNING | IFF_OACTIVE);
+	VR_UNLOCK(sc);
 
 	return;
 }
diff --git a/sys/pci/if_vrreg.h b/sys/pci/if_vrreg.h
index 2f2ac97..8217a8c 100644
--- a/sys/pci/if_vrreg.h
+++ b/sys/pci/if_vrreg.h
@@ -411,8 +411,12 @@ struct vr_softc {
 	struct vr_list_data	*vr_ldata;
 	struct vr_chain_data	vr_cdata;
 	struct callout_handle	vr_stat_ch;
+	struct mtx		vr_mtx;
 };
 
+#define	VR_LOCK(_sc)		mtx_enter(&(_sc)->vr_mtx, MTX_DEF)
+#define	VR_UNLOCK(_sc)		mtx_exit(&(_sc)->vr_mtx, MTX_DEF)
+
 /*
  * register space access macros
  */
diff --git a/sys/pci/if_wb.c b/sys/pci/if_wb.c
index b33c542..55316e3 100644
--- a/sys/pci/if_wb.c
+++ b/sys/pci/if_wb.c
@@ -392,9 +392,9 @@ static int wb_mii_readreg(sc, frame)
 	struct wb_mii_frame	*frame;
 	
 {
-	int			i, ack, s;
+	int			i, ack;
 
-	s = splimp();
+	WB_LOCK(sc);
 
 	/*
 	 * Set up frame for RX.
@@ -473,7 +473,7 @@ fail:
 	SIO_SET(WB_SIO_MII_CLK);
 	DELAY(1);
 
-	splx(s);
+	WB_UNLOCK(sc);
 
 	if (ack)
 		return(1);
@@ -488,9 +488,8 @@ static int wb_mii_writereg(sc, frame)
 	struct wb_mii_frame	*frame;
 	
 {
-	int			s;
+	WB_LOCK(sc);
 
-	s = splimp();
 	/*
 	 * Set up frame for TX.
 	 */
@@ -524,7 +523,7 @@ static int wb_mii_writereg(sc, frame)
 	 */
 	SIO_CLR(WB_SIO_MII_DIR);
 
-	splx(s);
+	WB_UNLOCK(sc);
 
 	return(0);
 }
@@ -574,8 +573,10 @@ static void wb_miibus_statchg(dev)
 	struct mii_data		*mii;
 
 	sc = device_get_softc(dev);
+	WB_LOCK(sc);
 	mii = device_get_softc(sc->wb_miibus);
 	wb_setcfg(sc, mii->mii_media_active);
+	WB_UNLOCK(sc);
 
 	return;
 }
@@ -808,15 +809,12 @@ static int wb_probe(dev)
 static int wb_attach(dev)
 	device_t		dev;
 {
-	int			s;
 	u_char			eaddr[ETHER_ADDR_LEN];
 	u_int32_t		command;
 	struct wb_softc		*sc;
 	struct ifnet		*ifp;
 	int			unit, error = 0, rid;
 
-	s = splimp();
-
 	sc = device_get_softc(dev);
 	unit = device_get_unit(dev);
 
@@ -909,6 +907,9 @@ static int wb_attach(dev)
 	/* Save the cache line size. */
 	sc->wb_cachesize = pci_read_config(dev, WB_PCI_CACHELEN, 4) & 0xFF;
 
+	mtx_init(&sc->wb_mtx, "wb", MTX_DEF);
+	WB_LOCK(sc);
+
 	/* Reset the adapter. */
 	wb_reset(sc);
 
@@ -970,11 +971,14 @@ static int wb_attach(dev)
 	 * Call MI attach routine.
 	 */
 	ether_ifattach(ifp, ETHER_BPF_SUPPORTED);
+	WB_UNLOCK(sc);
+	return(0);
 
 fail:
 	if (error)
 		device_delete_child(dev, sc->wb_miibus);
-	splx(s);
+	WB_UNLOCK(sc);
+	mtx_destroy(&sc->wb_mtx);
 
 	return(error);
 }
@@ -984,11 +988,9 @@ static int wb_detach(dev)
 {
 	struct wb_softc		*sc;
 	struct ifnet		*ifp;
-	int			s;
-
-	s = splimp();
 
 	sc = device_get_softc(dev);
+	WB_LOCK(sc);
 	ifp = &sc->arpcom.ac_if;
 
 	wb_stop(sc);
@@ -1004,7 +1006,8 @@ static int wb_detach(dev)
 
 	free(sc->wb_ldata_ptr, M_DEVBUF);
 
-	splx(s);
+	WB_UNLOCK(sc);
+	mtx_destroy(&sc->wb_mtx);
 
 	return(0);
 }
@@ -1303,10 +1306,13 @@ static void wb_intr(arg)
 	u_int32_t		status;
 
 	sc = arg;
+	WB_LOCK(sc);
 	ifp = &sc->arpcom.ac_if;
 
-	if (!(ifp->if_flags & IFF_UP))
+	if (!(ifp->if_flags & IFF_UP)) {
+		WB_UNLOCK(sc);
 		return;
+	}
 
 	/* Disable interrupts. */
 	CSR_WRITE_4(sc, WB_IMR, 0x00000000);
@@ -1374,6 +1380,8 @@ static void wb_intr(arg)
 		wb_start(ifp);
 	}
 
+	WB_UNLOCK(sc);
+
 	return;
 }
 
@@ -1382,18 +1390,16 @@ static void wb_tick(xsc)
 {
 	struct wb_softc		*sc;
 	struct mii_data		*mii;
-	int			s;
-
-	s = splimp();
 
 	sc = xsc;
+	WB_LOCK(sc);
 	mii = device_get_softc(sc->wb_miibus);
 
 	mii_tick(mii);
 
 	sc->wb_stat_ch = timeout(wb_tick, sc, hz);
 
-	splx(s);
+	WB_UNLOCK(sc);
 
 	return;
 }
@@ -1508,6 +1514,7 @@ static void wb_start(ifp)
 	struct wb_chain		*cur_tx = NULL, *start_tx;
 
 	sc = ifp->if_softc;
+	WB_LOCK(sc);
 
 	/*
 	 * Check for an available queue slot. If there are none,
@@ -1515,6 +1522,7 @@ static void wb_start(ifp)
 	 */
 	if (sc->wb_cdata.wb_tx_free->wb_mbuf != NULL) {
 		ifp->if_flags |= IFF_OACTIVE;
+		WB_UNLOCK(sc);
 		return;
 	}
 
@@ -1546,8 +1554,10 @@ static void wb_start(ifp)
 	/*
 	 * If there are no packets queued, bail.
 	 */
-	if (cur_tx == NULL)
+	if (cur_tx == NULL) {
+		WB_UNLOCK(sc);
 		return;
+	}
 
 	/*
 	 * Place the request for the upload interrupt
@@ -1584,6 +1594,7 @@ static void wb_start(ifp)
 	 * Set a timeout in case the chip goes out to lunch.
 	 */
 	ifp->if_timer = 5;
+	WB_UNLOCK(sc);
 
 	return;
 }
@@ -1593,11 +1604,10 @@ static void wb_init(xsc)
 {
 	struct wb_softc		*sc = xsc;
 	struct ifnet		*ifp = &sc->arpcom.ac_if;
-	int			s, i;
+	int			i;
 	struct mii_data		*mii;
 
-	s = splimp();
-
+	WB_LOCK(sc);
 	mii = device_get_softc(sc->wb_miibus);
 
 	/*
@@ -1648,7 +1658,7 @@ static void wb_init(xsc)
 		printf("wb%d: initialization failed: no "
 			"memory for rx buffers\n", sc->wb_unit);
 		wb_stop(sc);
-		(void)splx(s);
+		WB_UNLOCK(sc);
 		return;
 	}
 
@@ -1701,9 +1711,8 @@ static void wb_init(xsc)
 	ifp->if_flags |= IFF_RUNNING;
 	ifp->if_flags &= ~IFF_OACTIVE;
 
-	(void)splx(s);
-
 	sc->wb_stat_ch = timeout(wb_tick, sc, hz);
+	WB_UNLOCK(sc);
 
 	return;
 }
@@ -1753,9 +1762,9 @@ static int wb_ioctl(ifp, command, data)
 	struct wb_softc		*sc = ifp->if_softc;
 	struct mii_data		*mii;
 	struct ifreq		*ifr = (struct ifreq *) data;
-	int			s, error = 0;
+	int			error = 0;
 
-	s = splimp();
+	WB_LOCK(sc);
 
 	switch(command) {
 	case SIOCSIFADDR:
@@ -1787,7 +1796,7 @@ static int wb_ioctl(ifp, command, data)
 		break;
 	}
 
-	(void)splx(s);
+	WB_UNLOCK(sc);
 
 	return(error);
 }
@@ -1799,6 +1808,7 @@ static void wb_watchdog(ifp)
 
 	sc = ifp->if_softc;
 
+	WB_LOCK(sc);
 	ifp->if_oerrors++;
 	printf("wb%d: watchdog timeout\n", sc->wb_unit);
 #ifdef foo
@@ -1812,6 +1822,7 @@ static void wb_watchdog(ifp)
 
 	if (ifp->if_snd.ifq_head != NULL)
 		wb_start(ifp);
+	WB_UNLOCK(sc);
 
 	return;
 }
@@ -1826,6 +1837,7 @@ static void wb_stop(sc)
 	register int		i;
 	struct ifnet		*ifp;
 
+	WB_LOCK(sc);
 	ifp = &sc->arpcom.ac_if;
 	ifp->if_timer = 0;
 
@@ -1862,6 +1874,7 @@ static void wb_stop(sc)
 		sizeof(sc->wb_ldata->wb_tx_list));
 
 	ifp->if_flags &= ~(IFF_RUNNING | IFF_OACTIVE);
+	WB_UNLOCK(sc);
 
 	return;
 }
diff --git a/sys/pci/if_wbreg.h b/sys/pci/if_wbreg.h
index 5bfccd8..6f58514 100644
--- a/sys/pci/if_wbreg.h
+++ b/sys/pci/if_wbreg.h
@@ -378,8 +378,12 @@ struct wb_softc {
 	struct wb_list_data	*wb_ldata;
 	struct wb_chain_data	wb_cdata;
 	struct callout_handle	wb_stat_ch;
+	struct mtx		wb_mtx;
 };
 
+#define	WB_LOCK(_sc)		mtx_enter(&(_sc)->wb_mtx, MTX_DEF)
+#define	WB_UNLOCK(_sc)		mtx_exit(&(_sc)->wb_mtx, MTX_DEF)
+
 /*
  * register space access macros
  */
diff --git a/sys/pci/if_xl.c b/sys/pci/if_xl.c
index 8f72467..7e1f64b 100644
--- a/sys/pci/if_xl.c
+++ b/sys/pci/if_xl.c
@@ -387,9 +387,9 @@ static int xl_mii_readreg(sc, frame)
 	struct xl_mii_frame	*frame;
 	
 {
-	int			i, ack, s;
+	int			i, ack;
 
-	s = splimp();
+	XL_LOCK(sc);
 
 	/*
 	 * Set up frame for RX.
@@ -470,7 +470,7 @@ fail:
 	MII_SET(XL_MII_CLK);
 	DELAY(1);
 
-	splx(s);
+	XL_UNLOCK(sc);
 
 	if (ack)
 		return(1);
@@ -485,9 +485,8 @@ static int xl_mii_writereg(sc, frame)
 	struct xl_mii_frame	*frame;
 	
 {
-	int			s;
+	XL_LOCK(sc);
 
-	s = splimp();
 	/*
 	 * Set up frame for TX.
 	 */
@@ -526,7 +525,7 @@ static int xl_mii_writereg(sc, frame)
 	 */
 	MII_CLR(XL_MII_DIR);
 
-	splx(s);
+	XL_UNLOCK(sc);
 
 	return(0);
 }
@@ -592,6 +591,8 @@ static void xl_miibus_statchg(dev)
 	sc = device_get_softc(dev);
 	mii = device_get_softc(sc->xl_miibus);
 
+	XL_LOCK(sc);
+
 	xl_setcfg(sc);
 
 	/* Set ASIC's duplex mode to match the PHY. */
@@ -602,6 +603,8 @@ static void xl_miibus_statchg(dev)
 		CSR_WRITE_1(sc, XL_W3_MAC_CTRL,
 			(CSR_READ_1(sc, XL_W3_MAC_CTRL) & ~XL_MACCTRL_DUPLEX));
 
+	XL_UNLOCK(sc);
+
         return;
 }
 
@@ -626,6 +629,8 @@ static void xl_miibus_mediainit(dev)
 	mii = device_get_softc(sc->xl_miibus);
 	ifm = &mii->mii_media;
 
+	XL_LOCK(sc);
+
 	if (sc->xl_media & (XL_MEDIAOPT_AUI|XL_MEDIAOPT_10FL)) {
 		/*
 		 * Check for a 10baseFL board in disguise.
@@ -652,6 +657,8 @@ static void xl_miibus_mediainit(dev)
 		ifmedia_add(ifm, IFM_ETHER|IFM_10_2, 0, NULL);
 	}
 
+	XL_UNLOCK(sc);
+
 	return;
 }
 
@@ -1341,6 +1348,9 @@ static int xl_attach(dev)
 		goto fail;
 	}
 
+	mtx_init(&sc->xl_mtx, "xl", MTX_DEF);
+	XL_LOCK(sc);
+
 	/* Reset the adapter. */
 	xl_reset(sc);
 
@@ -1556,9 +1566,13 @@ done:
 	 * Call MI attach routine.
 	 */
 	ether_ifattach(ifp, ETHER_BPF_SUPPORTED);
+	XL_UNLOCK(sc);
+	return(0);
 
 fail:
-	splx(s);
+	XL_UNLOCK(sc);
+	mtx_destroy(&sc->xl_mtx);
+
 	return(error);
 }
 
@@ -1567,11 +1581,9 @@ static int xl_detach(dev)
 {
 	struct xl_softc		*sc;
 	struct ifnet		*ifp;
-	int			s;
-
-	s = splimp();
 
 	sc = device_get_softc(dev);
+	XL_LOCK(sc);
 	ifp = &sc->arpcom.ac_if;
 
 	xl_reset(sc);
@@ -1594,7 +1606,8 @@ static int xl_detach(dev)
 	ifmedia_removeall(&sc->ifmedia);
 	contigfree(sc->xl_ldata, sizeof(struct xl_list_data), M_DEVBUF);
 
-	splx(s);
+	XL_UNLOCK(sc);
+	mtx_destroy(&sc->xl_mtx);
 
 	return(0);
 }
@@ -2024,6 +2037,7 @@ static void xl_intr(arg)
 	u_int16_t		status;
 
 	sc = arg;
+	XL_LOCK(sc);
 	ifp = &sc->arpcom.ac_if;
 
 	while((status = CSR_READ_2(sc, XL_STATUS)) & XL_INTRS) {
@@ -2069,6 +2083,8 @@ static void xl_intr(arg)
 	if (ifp->if_snd.ifq_head != NULL)
 		(*ifp->if_start)(ifp);
 
+	XL_LOCK(sc);
+
 	return;
 }
 
@@ -2215,7 +2231,7 @@ static void xl_start(ifp)
 	struct xl_chain		*prev = NULL, *cur_tx = NULL, *start_tx;
 
 	sc = ifp->if_softc;
-
+	XL_LOCK(sc);
 	/*
 	 * Check for an available queue slot. If there are none,
 	 * punt.
@@ -2225,6 +2241,7 @@ static void xl_start(ifp)
 		xl_txeof(sc);
 		if (sc->xl_cdata.xl_tx_free == NULL) {
 			ifp->if_flags |= IFF_OACTIVE;
+			XL_UNLOCK(sc);
 			return;
 		}
 	}
@@ -2263,8 +2280,10 @@ static void xl_start(ifp)
 	/*
 	 * If there are no packets queued, bail.
 	 */
-	if (cur_tx == NULL)
+	if (cur_tx == NULL) {
+		XL_UNLOCK(sc);
 		return;
+	}
 
 	/*
 	 * Place the request for the upload interrupt
@@ -2322,6 +2341,8 @@ static void xl_start(ifp)
 	 */
 	xl_rxeof(sc);
 
+	XL_UNLOCK(sc);
+
 	return;
 }
 
@@ -2371,9 +2392,12 @@ static void xl_start_90xB(ifp)
 	int			idx;
 
 	sc = ifp->if_softc;
+	XL_LOCK(sc);
 
-	if (ifp->if_flags & IFF_OACTIVE)
+	if (ifp->if_flags & IFF_OACTIVE) {
+		XL_UNLOCK(sc);
 		return;
+	}
 
 	idx = sc->xl_cdata.xl_tx_prod;
 	start_tx = &sc->xl_cdata.xl_tx_chain[idx];
@@ -2413,8 +2437,10 @@ static void xl_start_90xB(ifp)
 	/*
 	 * If there are no packets queued, bail.
 	 */
-	if (cur_tx == NULL)
+	if (cur_tx == NULL) {
+		XL_UNLOCK(sc);
 		return;
+	}
 
 	/*
 	 * Place the request for the upload interrupt
@@ -2434,6 +2460,8 @@ static void xl_start_90xB(ifp)
 	 */
 	ifp->if_timer = 5;
 
+	XL_UNLOCK(sc);
+
 	return;
 }
 
@@ -2442,11 +2470,11 @@ static void xl_init(xsc)
 {
 	struct xl_softc		*sc = xsc;
 	struct ifnet		*ifp = &sc->arpcom.ac_if;
-	int			s, i;
+	int			i;
 	u_int16_t		rxfilt = 0;
 	struct mii_data		*mii = NULL;
 
-	s = splimp();
+	XL_LOCK(sc);
 
 	/*
 	 * Cancel pending I/O and free all RX/TX buffers.
@@ -2610,7 +2638,8 @@ static void xl_init(xsc)
 	CSR_WRITE_2(sc, XL_COMMAND, XL_CMD_INTR_ACK|0xFF);
 	CSR_WRITE_2(sc, XL_COMMAND, XL_CMD_STAT_ENB|XL_INTRS);
 	CSR_WRITE_2(sc, XL_COMMAND, XL_CMD_INTR_ENB|XL_INTRS);
-	if (sc->xl_flags & XL_FLAG_FUNCREG) bus_space_write_4 (sc->xl_ftag, sc->xl_fhandle, 4, 0x8000);
+	if (sc->xl_flags & XL_FLAG_FUNCREG)
+	    bus_space_write_4(sc->xl_ftag, sc->xl_fhandle, 4, 0x8000);
 
 	/* Set the RX early threshold */
 	CSR_WRITE_2(sc, XL_COMMAND, XL_CMD_RX_SET_THRESH|(XL_PACKET_SIZE >>2));
@@ -2631,10 +2660,10 @@ static void xl_init(xsc)
 	ifp->if_flags |= IFF_RUNNING;
 	ifp->if_flags &= ~IFF_OACTIVE;
 
-	(void)splx(s);
-
 	sc->xl_stat_ch = timeout(xl_stats_update, sc, hz);
 
+	XL_UNLOCK(sc);
+
 	return;
 }
 
@@ -2752,11 +2781,11 @@ static int xl_ioctl(ifp, command, data)
 {
 	struct xl_softc		*sc = ifp->if_softc;
 	struct ifreq		*ifr = (struct ifreq *) data;
-	int			s, error = 0;
+	int			error = 0;
 	struct mii_data		*mii = NULL;
 	u_int8_t		rxfilt;
 
-	s = splimp();
+	XL_LOCK(sc);
 
 	switch(command) {
 	case SIOCSIFADDR:
@@ -2815,7 +2844,7 @@ static int xl_ioctl(ifp, command, data)
 		break;
 	}
 
-	(void)splx(s);
+	XL_UNLOCK(sc);
 
 	return(error);
 }
@@ -2828,6 +2857,8 @@ static void xl_watchdog(ifp)
 
 	sc = ifp->if_softc;
 
+	XL_LOCK(sc);
+
 	ifp->if_oerrors++;
 	XL_SEL_WIN(4);
 	status = CSR_READ_2(sc, XL_W4_MEDIA_STATUS);
@@ -2845,6 +2876,8 @@ static void xl_watchdog(ifp)
 	if (ifp->if_snd.ifq_head != NULL)
 		(*ifp->if_start)(ifp);
 
+	XL_UNLOCK(sc);
+
 	return;
 }
 
@@ -2858,6 +2891,8 @@ static void xl_stop(sc)
 	register int		i;
 	struct ifnet		*ifp;
 
+	XL_LOCK(sc);
+
 	ifp = &sc->arpcom.ac_if;
 	ifp->if_timer = 0;
 
@@ -2910,6 +2945,8 @@ static void xl_stop(sc)
 
 	ifp->if_flags &= ~(IFF_RUNNING | IFF_OACTIVE);
 
+	XL_UNLOCK(sc);
+
 	return;
 }
 
@@ -2924,8 +2961,10 @@ static void xl_shutdown(dev)
 
 	sc = device_get_softc(dev);
 
+	XL_LOCK(sc);
 	xl_reset(sc);
 	xl_stop(sc);
+	XL_UNLOCK(sc);
 
 	return;
 }
diff --git a/sys/pci/if_xlreg.h b/sys/pci/if_xlreg.h
index eccf669..108823c 100644
--- a/sys/pci/if_xlreg.h
+++ b/sys/pci/if_xlreg.h
@@ -579,8 +579,12 @@ struct xl_softc {
 	struct resource		*xl_fres;
 	bus_space_handle_t	xl_fhandle;
 	bus_space_tag_t		xl_ftag;
+	struct mtx		xl_mtx;
 };
 
+#define XL_LOCK(_sc)		mtx_enter(&(_sc)->xl_mtx, MTX_DEF)
+#define XL_UNLOCK(_sc)		mtx_exit(&(_sc)->xl_mtx, MTX_DEF)
+
 #define xl_rx_goodframes(x) \
 	((x.xl_upper_frames_ok & 0x03) << 8) | x.xl_rx_frames_ok