Re: NIU - Sun Neptune 10g - Transmit timed out reset (2.6.24)

David Miller
2008-05-26T19:40:11Z

From: David Miller <davem@davemloft.net>
Date: Mon, 26 May 2008 12:33:38 -0700 (PDT)

> From: Jesper Krogh <jesper@krogh.cc>
> Date: Mon, 26 May 2008 21:03:34 +0200
>
> > Ok. Now I also hit it in production with the NFS-server, so this
> > is definately a real bug somewhere in the driver. Should I register it
> > at bugzilla?
>
> Please feel free to do that.

BTW, I did stare at some of the transmit code of the NIU driver
while flying from Tokyo to Seattle a few hours ago, and I
found one possible theory on the transmit timeouts.

Can you try the patch below and let us know if the symptoms
continue?

[ Note to Matheos: The IRQ marking scheme of the NIU doesn't mesh
well with how things work under Linux. We really needs a
"TX queue empty" interrupt status in order to handle all cases
properly. Otherwise we really cannot decide not mark some TX
descriptors without potentially entering a deadlock condition. ]

diff --git a/drivers/net/niu.c b/drivers/net/niu.c
index 918f802..7ab7f8e 100644
--- a/drivers/net/niu.c
+++ b/drivers/net/niu.c
@@ -6165,7 +6165,7 @@ static int niu_start_xmit(struct sk_buff *skb, struct net_device *dev)
rp->tx_buffs[prod].mapping = mapping;

mrk = TX_DESC_SOP;
- if (++rp->mark_counter == rp->mark_freq) {
+ if (1 /*++rp->mark_counter == rp->mark_freq*/) {
rp->mark_counter = 0;
mrk |= TX_DESC_MARK;
rp->mark_pending++;