diff options
| author | Andreas Oberritter <obi@linuxtv.org> | 2008-10-08 06:14:16 +0000 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2008-10-08 17:12:57 -0700 |
| commit | 176eaa589b3d242f25f24e472883fcce5f196777 (patch) | |
| tree | 5b6f51c49accccc5690aaeba7754cf150dd25c43 | |
| parent | ed4cb1337b7c23b91a0f01f661c3f004fc3d3c1a (diff) | |
| download | lwn-176eaa589b3d242f25f24e472883fcce5f196777.tar.gz lwn-176eaa589b3d242f25f24e472883fcce5f196777.zip | |
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 <obi@linuxtv.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
| -rw-r--r-- | drivers/net/8139too.c | 7 |
1 files changed, 6 insertions, 1 deletions
diff --git a/drivers/net/8139too.c b/drivers/net/8139too.c index 32e66f0d4344..0daf8c15e381 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); |