diff --git a/drivers/net/rtl8139.c b/drivers/net/rtl8139.c
index 1afc6a10..c7978fdf 100644
--- a/drivers/net/rtl8139.c
+++ b/drivers/net/rtl8139.c
@@ -113,7 +113,8 @@ static err_t rtl8139if_output(struct netif* netif, struct pbuf* p)
 static void rtl8139if_input(struct netif* netif, struct pbuf* p)
 {
 	struct eth_hdr *ethhdr;
- 
+	err_t	err;
+
 	/* points to packet payload, which starts with an Ethernet header */
 	ethhdr = p->payload;
 
@@ -127,8 +128,9 @@ static void rtl8139if_input(struct netif* netif, struct pbuf* p)
 	case ETHTYPE_PPPOE:
 #endif /* PPPOE_SUPPORT */
 		/* full packet send to tcpip_thread to process */
-		if (mynetif->input(p, mynetif) != ERR_OK) {
-			LWIP_DEBUGF(NETIF_DEBUG, ("rtl8139if_input: IP input error\n"));
+		err = mynetif->input(p, mynetif);
+		if (err != ERR_OK) {
+			LWIP_DEBUGF(NETIF_DEBUG, ("rtl8139if_input: IP input error %d\n", (int32_t) err));
 			pbuf_free(p);
 		}
 		break;