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Re: [PATCH 1/2 2.6] e100: fix NAPI race with watchdog

To: Jesse Brandeburg <jesse.brandeburg@xxxxxxxxx>
Subject: Re: [PATCH 1/2 2.6] e100: fix NAPI race with watchdog
From: Stephen Hemminger <shemminger@xxxxxxxx>
Date: Wed, 22 Sep 2004 13:38:23 -0700
Cc: jgarzik@xxxxxxxxx, netdev@xxxxxxxxxxx
In-reply-to: <Pine.LNX.4.44.0409221217010.7544-100000@xxxxxxxxxxxxxxxxxxxx>
Organization: Open Source Development Lab
References: <Pine.LNX.4.44.0409221217010.7544-100000@xxxxxxxxxxxxxxxxxxxx>
Sender: netdev-bounce@xxxxxxxxxxx
On Wed, 22 Sep 2004 12:25:44 -0700 (PDT)
Jesse Brandeburg <jesse.brandeburg@xxxxxxxxx> wrote:

> While polling in NAPI mode, we were occassionally getting interrupts 
> re-enabled by the watchdog trying to generate a software interrupt.  Fix 
> is to add a spinlock around that shared hardware register to allow a 
> read-modify-write operation.  This was nasty nasty.  I don't like the 
> spinlock in the hot path but i see no other way.  Comments are welcome.
> Updates the driver version as well.

You could convert it to LLTX then at least there is only one lock roundtrip

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