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Date:	Mon, 28 Jun 2010 12:00:51 +0200
From:	Eric Dumazet <eric.dumazet@...il.com>
To:	Mitchell Erblich <erblichs@...thlink.net>
Cc:	James Courtier-Dutton <james.dutton@...il.com>,
	netdev@...r.kernel.org
Subject: Re: b44: Reset due to FIFO overflow.

Le lundi 28 juin 2010 à 02:33 -0700, Mitchell Erblich a écrit :

> 
> Why wouldn't the ability to recv frames after a Recv FIFO overflow
>  indicate that a reset is NOT required?
> 

Do you have datasheets of all b44 chips ? I dont.

> Thus,  should't it be an indication of congestion if associated with a single
> flow and either speed up (reduce latency to service) the recv side or 
> slow down the xmit side?

I dont understand what you are saying. xmit is not the problem here.
And driver is flow agnostic. Its well before network stack.

Problem is we receive a spike of RX network frames (possibly UDP or some
other RX only trafic), and chip raises an RX fifo overflow _error_
indication.

Some hardware are buggy enough that such error indication is fatal and
_require_ hardware reset. Thats life. I suspect b44 driver doing a full
reset is not a random guess from driver author, but to avoid a complete
NIC lockup.

Refs:

http://bugzilla.kernel.org/show_bug.cgi?id=7696
https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=216338

commit 5fc7d61aee1a7f7d3448f8fbccaa93371ebeecb0



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