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Date: Wed, 06 Sep 2006 09:25:34 +0100
From: Alex Zeffertt <ajz@cambridgebroadband.com>
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To: "David H. Lynch Jr." <dhlii@dlasys.net>
Subject: Re: MAC driver issue
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>> FWIW, in my experience the hardware independent parts of the 
>> networking stack are
>> very stable and the problem is almost always with the drivers, or with 
>> the IP
>> configuration (e.g. two interfaces on the same subnet).

>     I have no doubt it is with the driver.  I am somewhat fortunate in 
> this instance that I have a nearly identical setup - this is an FPGA 
> based system
>     I can swap the FPGA firmware, get an almost identical kernel with a 
> slightly different NIC, and everything works - same cables, same IP's,
>     Same switch, The only things different are the NIC and its driver. 
> Even the Linux kernels are identical - except the NIC driver.
>    
>     BUT so is the data received and passed on to the kernel (outside 
> random differences in the padding of the ARP packet)
>     One works the other doesn't.
> 

Well ethernet device drivers contain multiple arp supporting methods,
e.g. header_cache, header_cache_update, hard_header_parse, etc etc.
Generally driver writers don't need to concern themselves about these
as they are assigned to generic handlers by ether_setup().  However,
your problematic driver may do something different.

Given this problem appears to be driver specific rather than PPC
specific your best bet is to try and contact the author.  BTW, I don't
think you've said which driver you are using, a key piece of info....

Alex