diff --git a/sys/dev/mvs/mvs.c b/sys/dev/mvs/mvs.c
index 2694d9cc380a..1cc0fae21956 100644
--- a/sys/dev/mvs/mvs.c
+++ b/sys/dev/mvs/mvs.c
@@ -51,6 +51,8 @@ __FBSDID("$FreeBSD$");
 #include <cam/cam_debug.h>
 
 /* local prototypes */
+static int mvs_ch_init(device_t dev);
+static int mvs_ch_deinit(device_t dev);
 static int mvs_ch_suspend(device_t dev);
 static int mvs_ch_resume(device_t dev);
 static void mvs_dmainit(device_t dev);
@@ -133,7 +135,7 @@ mvs_ch_attach(device_t dev)
 		return (ENXIO);
 	mvs_dmainit(dev);
 	mvs_slotsalloc(dev);
-	mvs_ch_resume(dev);
+	mvs_ch_init(dev);
 	mtx_lock(&ch->mtx);
 	rid = ATA_IRQ_RID;
 	if (!(ch->r_irq = bus_alloc_resource_any(dev, SYS_RES_IRQ,
@@ -215,7 +217,7 @@ mvs_ch_detach(device_t dev)
 	bus_teardown_intr(dev, ch->r_irq, ch->ih);
 	bus_release_resource(dev, SYS_RES_IRQ, ATA_IRQ_RID, ch->r_irq);
 
-	mvs_ch_suspend(dev);
+	mvs_ch_deinit(dev);
 	mvs_slotsfree(dev);
 	mvs_dmafini(dev);
 
@@ -225,19 +227,7 @@ mvs_ch_detach(device_t dev)
 }
 
 static int
-mvs_ch_suspend(device_t dev)
-{
-	struct mvs_channel *ch = device_get_softc(dev);
-
-	/* Stop EDMA */
-	mvs_set_edma_mode(dev, MVS_EDMA_OFF);
-	/* Disable port interrupts. */
-	ATA_OUTL(ch->r_mem, EDMA_IEM, 0);
-	return (0);
-}
-
-static int
-mvs_ch_resume(device_t dev)
+mvs_ch_init(device_t dev)
 {
 	struct mvs_channel *ch = device_get_softc(dev);
 	uint32_t reg;
@@ -264,6 +254,45 @@ mvs_ch_resume(device_t dev)
 	return (0);
 }
 
+static int
+mvs_ch_deinit(device_t dev)
+{
+	struct mvs_channel *ch = device_get_softc(dev);
+
+	/* Stop EDMA */
+	mvs_set_edma_mode(dev, MVS_EDMA_OFF);
+	/* Disable port interrupts. */
+	ATA_OUTL(ch->r_mem, EDMA_IEM, 0);
+	return (0);
+}
+
+static int
+mvs_ch_suspend(device_t dev)
+{
+	struct mvs_channel *ch = device_get_softc(dev);
+
+	mtx_lock(&ch->mtx);
+	xpt_freeze_simq(ch->sim, 1);
+	while (ch->oslots)
+		msleep(ch, &ch->mtx, PRIBIO, "mvssusp", hz/100);
+	mvs_ch_deinit(dev);
+	mtx_unlock(&ch->mtx);
+	return (0);
+}
+
+static int
+mvs_ch_resume(device_t dev)
+{
+	struct mvs_channel *ch = device_get_softc(dev);
+
+	mtx_lock(&ch->mtx);
+	mvs_ch_init(dev);
+	mvs_reset(dev);
+	xpt_release_simq(ch->sim, TRUE);
+	mtx_unlock(&ch->mtx);
+	return (0);
+}
+
 struct mvs_dc_cb_args {
 	bus_addr_t maddr;
 	int error;
diff --git a/sys/dev/siis/siis.c b/sys/dev/siis/siis.c
index 937d04cfa1d7..75eb26fb3905 100644
--- a/sys/dev/siis/siis.c
+++ b/sys/dev/siis/siis.c
@@ -59,6 +59,8 @@ static int siis_setup_interrupt(device_t dev);
 static void siis_intr(void *data);
 static int siis_suspend(device_t dev);
 static int siis_resume(device_t dev);
+static int siis_ch_init(device_t dev);
+static int siis_ch_deinit(device_t dev);
 static int siis_ch_suspend(device_t dev);
 static int siis_ch_resume(device_t dev);
 static void siis_ch_intr_locked(void *data);
@@ -458,7 +460,7 @@ siis_ch_attach(device_t dev)
 		return (ENXIO);
 	siis_dmainit(dev);
 	siis_slotsalloc(dev);
-	siis_ch_resume(dev);
+	siis_ch_init(dev);
 	mtx_lock(&ch->mtx);
 	rid = ATA_IRQ_RID;
 	if (!(ch->r_irq = bus_alloc_resource_any(dev, SYS_RES_IRQ,
@@ -528,7 +530,7 @@ siis_ch_detach(device_t dev)
 	bus_teardown_intr(dev, ch->r_irq, ch->ih);
 	bus_release_resource(dev, SYS_RES_IRQ, ATA_IRQ_RID, ch->r_irq);
 
-	siis_ch_suspend(dev);
+	siis_ch_deinit(dev);
 	siis_slotsfree(dev);
 	siis_dmafini(dev);
 
@@ -538,17 +540,7 @@ siis_ch_detach(device_t dev)
 }
 
 static int
-siis_ch_suspend(device_t dev)
-{
-	struct siis_channel *ch = device_get_softc(dev);
-
-	/* Put port into reset state. */
-	ATA_OUTL(ch->r_mem, SIIS_P_CTLSET, SIIS_P_CTL_PORT_RESET);
-	return (0);
-}
-
-static int
-siis_ch_resume(device_t dev)
+siis_ch_init(device_t dev)
 {
 	struct siis_channel *ch = device_get_softc(dev);
 
@@ -564,6 +556,43 @@ siis_ch_resume(device_t dev)
 	return (0);
 }
 
+static int
+siis_ch_deinit(device_t dev)
+{
+	struct siis_channel *ch = device_get_softc(dev);
+
+	/* Put port into reset state. */
+	ATA_OUTL(ch->r_mem, SIIS_P_CTLSET, SIIS_P_CTL_PORT_RESET);
+	return (0);
+}
+
+static int
+siis_ch_suspend(device_t dev)
+{
+	struct siis_channel *ch = device_get_softc(dev);
+
+	mtx_lock(&ch->mtx);
+	xpt_freeze_simq(ch->sim, 1);
+	while (ch->oslots)
+		msleep(ch, &ch->mtx, PRIBIO, "siissusp", hz/100);
+	siis_ch_deinit(dev);
+	mtx_unlock(&ch->mtx);
+	return (0);
+}
+
+static int
+siis_ch_resume(device_t dev)
+{
+	struct siis_channel *ch = device_get_softc(dev);
+
+	mtx_lock(&ch->mtx);
+	siis_ch_init(dev);
+	siis_reset(dev);
+	xpt_release_simq(ch->sim, TRUE);
+	mtx_unlock(&ch->mtx);
+	return (0);
+}
+
 devclass_t siisch_devclass;
 static device_method_t siisch_methods[] = {
 	DEVMETHOD(device_probe,     siis_ch_probe),