diff --git a/sys/arm/allwinner/aw_mmc.c b/sys/arm/allwinner/aw_mmc.c
--- a/sys/arm/allwinner/aw_mmc.c
+++ b/sys/arm/allwinner/aw_mmc.c
@@ -317,36 +317,41 @@
 aw_mmc_helper_cd_handler(device_t dev, bool present)
 {
 	struct aw_mmc_softc *sc;
+#ifndef MMCCAM
+	device_t child;
+#endif
 
 	sc = device_get_softc(dev);
 #ifdef MMCCAM
 	mmc_cam_sim_discover(&sc->mmc_sim);
 #else
 	AW_MMC_LOCK(sc);
-	if (present) {
-		if (sc->child == NULL) {
-			if (__predict_false(aw_mmc_debug & AW_MMC_DEBUG_CARD))
-				device_printf(sc->aw_dev, "Card inserted\n");
+	child = sc->child;
+	AW_MMC_UNLOCK(sc);
 
-			sc->child = device_add_child(sc->aw_dev, "mmc", DEVICE_UNIT_ANY);
-			AW_MMC_UNLOCK(sc);
-			if (sc->child) {
-				device_set_ivars(sc->child, sc);
-				(void)device_probe_and_attach(sc->child);
-			}
-		} else
-			AW_MMC_UNLOCK(sc);
-	} else {
-		/* Card isn't present, detach if necessary */
-		if (sc->child != NULL) {
-			if (__predict_false(aw_mmc_debug & AW_MMC_DEBUG_CARD))
-				device_printf(sc->aw_dev, "Card removed\n");
+	if (present && child == NULL) {
+		if (__predict_false(aw_mmc_debug & AW_MMC_DEBUG_CARD))
+			device_printf(sc->aw_dev, "Card inserted\n");
 
-			AW_MMC_UNLOCK(sc);
-			device_delete_child(sc->aw_dev, sc->child);
-			sc->child = NULL;
-		} else
-			AW_MMC_UNLOCK(sc);
+		child = device_add_child(sc->aw_dev, "mmc", DEVICE_UNIT_ANY);
+		if (child != NULL) {
+			device_set_ivars(child, sc);
+			(void)device_probe_and_attach(child);
+		}
+
+		AW_MMC_LOCK(sc);
+		sc->child = child;
+		AW_MMC_UNLOCK(sc);
+	} else if (!present && child != NULL) {
+		/* Card isn't present, detach. */
+		if (__predict_false(aw_mmc_debug & AW_MMC_DEBUG_CARD))
+			device_printf(sc->aw_dev, "Card removed\n");
+
+		AW_MMC_LOCK(sc);
+		sc->child = NULL;
+		AW_MMC_UNLOCK(sc);
+
+		device_delete_child(sc->aw_dev, child);
 	}
 #endif /* MMCCAM */
 }