diff --git a/drivers/net/macb.c b/drivers/net/macb.c
index 489c7c3..d513bb8 100644
--- a/drivers/net/macb.c
+++ b/drivers/net/macb.c
@@ -246,7 +246,7 @@
 	bp->mii_bus.read = &macb_mdio_read;
 	bp->mii_bus.write = &macb_mdio_write;
 	bp->mii_bus.reset = &macb_mdio_reset;
-	bp->mii_bus.id = bp->pdev->id;
+	snprintf(bp->mii_bus.id, MII_BUS_ID_SIZE, "%x", bp->pdev->id);
 	bp->mii_bus.priv = bp;
 	bp->mii_bus.dev = &bp->dev->dev;
 	pdata = bp->pdev->dev.platform_data;