From 176eaa589b3d242f25f24e472883fcce5f196777 Mon Sep 17 00:00:00 2001 From: Andreas Oberritter Date: Wed, 8 Oct 2008 06:14:16 +0000 Subject: [PATCH] 8139too: move wmb before TX DMA start The write barrier should be used before starting a DMA transfer. This fixes a problem, where almost all packets received on another machine had garbled content. Tested with an RTL8100C on a MIPS machine. Signed-off-by: Andreas Oberritter Signed-off-by: David S. Miller --- drivers/net/8139too.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/drivers/net/8139too.c b/drivers/net/8139too.c index 32e66f0..0daf8c1 100644 --- a/drivers/net/8139too.c +++ b/drivers/net/8139too.c @@ -1723,13 +1723,18 @@ static int rtl8139_start_xmit (struct sk_buff *skb, struct net_device *dev) } spin_lock_irqsave(&tp->lock, flags); + /* + * Writing to TxStatus triggers a DMA transfer of the data + * copied to tp->tx_buf[entry] above. Use a memory barrier + * to make sure that the device sees the updated data. + */ + wmb(); RTL_W32_F (TxStatus0 + (entry * sizeof (u32)), tp->tx_flag | max(len, (unsigned int)ETH_ZLEN)); dev->trans_start = jiffies; tp->cur_tx++; - wmb(); if ((tp->cur_tx - NUM_TX_DESC) == tp->dirty_tx) netif_stop_queue (dev); -- 2.7.4