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8139too: move wmb before TX DMA start

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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 <obi@linuxtv.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Andreas Oberritter 2008-10-08 06:14:16 +00:00 committed by David S. Miller
parent ed4cb1337b
commit 176eaa589b
1 changed files with 6 additions and 1 deletions
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7
drivers/net/8139too.c
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@ -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);