Index: linux-2.6.30.10/drivers/net/bcm63xx_enet.c
===================================================================
--- linux-2.6.30.10.orig/drivers/net/bcm63xx_enet.c	2010-02-18 12:57:05.332799586 -0500
+++ linux-2.6.30.10/drivers/net/bcm63xx_enet.c	2010-02-18 12:57:53.954051082 -0500
@@ -1520,7 +1520,7 @@
 	actual_mtu = mtu;
 
 	/* add ethernet header + vlan tag size */
-	actual_mtu += VLAN_ETH_HLEN;
+	actual_mtu += VLAN_ETH_HLEN + VLAN_HLEN;
 
 	if (actual_mtu < 64 || actual_mtu > BCMENET_MAX_MTU)
 		return -EINVAL;