Re: lockups with netconsole on e1000 on media insertion

[Steven Rostedt <rostedt@goodmis.org>]

On Sun, 2005-08-07 at 23:12 +0200, John Bäckstrand wrote:
> Steven Rostedt wrote:
> > I don't have the card, so I can't test it. But if this works (after
> > removing the previous patch) then this is the better solution. 
> 
> I can confirm that this alone does not work for the simple 
> unplug/re-plug cycle I described, it still locks up hard. Tried this 
> alone on -rc6.

Darn it.  If I had a e1000 I could debug it. I have other methods of
logging than printks in all there varieties (see relayfs and friends).
I still believe that the e1000_netpoll is not turning on the queue for
some reason and the netpoll_send_skb is locking up because of that.
Especially since Andi's patch fixes the problem.

In e1000_clean_tx_irq, which I added to the e1000_netpoll call, has the
following lines:

        if(unlikely(cleaned && netif_queue_stopped(netdev) &&
                    netif_carrier_ok(netdev)))
                netif_wake_queue(netdev);


The netif_queue_stopped is true, since that causes the looping in
netpoll_send_pkt.  So either it didn't clean any buffers (cleaned is
false) or netif_carrier_ok is false.  I don't know what the e1000 does
when you pull the cable while it's transmitting, does it call the
e1000_down? If so it could cause the carrier_ok to fail.

Oh well, someone with a e1000 card will need to look into this. The
problem should be easily found.  Good luck.

-- Steve