--- /dev/null
+--- a/drivers/net/ethernet/lantiq_etop.c
++++ b/drivers/net/ethernet/lantiq_etop.c
+@@ -31,6 +31,7 @@
+ #include <linux/mm.h>
+ #include <linux/platform_device.h>
+ #include <linux/ethtool.h>
++#include <linux/if_vlan.h>
+ #include <linux/init.h>
+ #include <linux/delay.h>
+ #include <linux/io.h>
+@@ -764,8 +765,10 @@ ltq_etop_change_mtu(struct net_device *d
+ struct ltq_etop_priv *priv = netdev_priv(dev);
+ unsigned long flags;
+
++ int max = ETH_HLEN + VLAN_HLEN + new_mtu + ETH_FCS_LEN;
++
+ spin_lock_irqsave(&priv->lock, flags);
+- ltq_etop_w32((ETOP_PLEN_UNDER << 16) | new_mtu,
++ ltq_etop_w32((ETOP_PLEN_UNDER << 16) | max,
+ LTQ_ETOP_IGPLEN);
+ spin_unlock_irqrestore(&priv->lock, flags);
+ }