via-rhine: fix VLAN priority field (PCP, IEEE 802.1p)

Outgoing packets sent by via-rhine have their VLAN PCP field off by one
(when hardware acceleration is enabled). The TX descriptor expects only VID
and PCP (without a CFI/DEI bit).

Peter Boström noticed and reported the bug.

Signed-off-by: Roger Luethi <rl@hellgate.ch>
Cc: Peter Boström <peter.bostrom@netrounds.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/via/via-rhine.c

@@ -32,7 +32,7 @@
 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
 
 #define DRV_NAME	"via-rhine"
-#define DRV_VERSION	"1.5.0"
+#define DRV_VERSION	"1.5.1"
 #define DRV_RELDATE	"2010-10-09"
 
 #include <linux/types.h>
@@ -1704,7 +1704,12 @@ static netdev_tx_t rhine_start_tx(struct sk_buff *skb,
 		cpu_to_le32(TXDESC | (skb->len >= ETH_ZLEN ? skb->len : ETH_ZLEN));
 
 	if (unlikely(vlan_tx_tag_present(skb))) {
-		rp->tx_ring[entry].tx_status = cpu_to_le32((vlan_tx_tag_get(skb)) << 16);
+		u16 vid_pcp = vlan_tx_tag_get(skb);
+
+		/* drop CFI/DEI bit, register needs VID and PCP */
+		vid_pcp = (vid_pcp & VLAN_VID_MASK) |
+			  ((vid_pcp & VLAN_PRIO_MASK) >> 1);
+		rp->tx_ring[entry].tx_status = cpu_to_le32((vid_pcp) << 16);
 		/* request tagging */
 		rp->tx_ring[entry].desc_length |= cpu_to_le32(0x020000);
 	}