[vortex-bug] 3c556 TX bug ???

[Andrew Morton]

Felix Lindner wrote:
> 
> Hi list,
> 
> I discovered a funny issue with the following driver on a Laptop:
> 
> 3c59x: Donald Becker and others. www.scyld.com/network/vortex.html
> 02:06.0: 3Com PCI 3c556 Laptop Tornado at 0xe800. Vers LK1.1.16
> 
> When doing a netcat to a echo-like server such as this:
> nc -n -v 1.2.3.4 7 </dev/urandom
> and having a tcpdump running beside that, the communication would stop
> after aprx 30 seconds. Then, I could see traffic on the network using
> the tcpdump but my NIC did not send anything anymore. I assume the TX
> queue raised an error and awaits a reset from the driver it never gets.
> 
> Any ideas on what this is? Could that be related to the driver messages
> I see once in a while in syslog:
>  eth0: Transmit error, Tx status register 90.

Transmit underrun.  The NIC wasn't able to read
data from main memory across PCI fast enough.

That's unusual.

The driver does issue a Tx Reset in response to this.

I'm not sure what could be causing this.