Subject: Re: "dribbling bit"
To: Michael Richardson <mcr@sandelman.ottawa.on.ca>
From: Thor Lancelot Simon <tls@rek.tjls.com>
List: tech-net
Date: 01/21/2003 07:33:35
On Mon, Jan 20, 2003 at 10:43:56AM -0500, Michael Richardson wrote:
> 
> My firewall has started to do:
> 
> Jan 20 10:35:20 bud /netbsd: tlp0: receive error: dribbling bit
> Jan 20 10:35:20 bud /netbsd: tlp0: receive error: CRC error
> Jan 20 10:35:22 bud /netbsd: tlp0: receive error: dribbling bit
> Jan 20 10:35:22 bud /netbsd: tlp0: receive error: CRC error

This is usually a symptom of a duplex mismatch or MII configuration
problem.  Unfortunately, the various 21x4x and clones use a truly
wild variety of physical interface mechanisms and don't present a
uniform interface for configuring them; worse, some of them don't
do Nway negotiation in hardware but require a software state 
machine.  Our driver is a lot better than it was, but doesn't
always get it right, and with some chips it's worse than that: the
driver will somehow get out of sync after everything's worked fine
for a long time.

Thor