[Top] [All Lists]

Re: smc91x support

Subject: Re: smc91x support
From: Matej Kupljen <>
Date: Thu, 10 Nov 2005 18:44:30 +0100
Cc: Atsushi Nemoto <>,
In-reply-to: <>
Organization: Ultra d.o.o.
Original-recipient: rfc822;
References: <1131634331.18165.30.camel@localhost.localdomain> <> <>

> > matej> Is there any solution to this?
> > 
> > I have similar problem on my several custom boards with SMC91C111.  I
> > see so many RX overrun, but I can not see why it happens.  Forcing to
> > 10Mbps/HalfDuplex reduced the overrun count (and works better than
> > 100Mbps), but it is not preferable, of course ...

How did you achieve this? By software or by using 10 Mbps switch?

> And yes performance is bad with this chip. 

Probably I'll try and switch it to 10 Mbps, because NFS is terrible
because it gets a lot of timeouts because of dropped packets.

> I'm not sure if DMA would
> help much, since the overrun occurs because the chip does not have
> enough internal buffers. I don't think that we can service the interrupts
> fast enough to prevent the overruns...

I found this mail from Nicolas on ARM mailing list:

Maybe we could try DMA and see what happens.
Any hints how to try this, because I haven't worked with DDMA before?


<Prev in Thread] Current Thread [Next in Thread>