Subject: Re: pciide, DMA, and the alpha...
To: Bill Studenmund <>
From: Manuel Bouyer <>
List: port-alpha
Date: 08/12/1999 19:08:09
On Thu, Aug 12, 1999 at 10:04:06AM -0700, Bill Studenmund wrote:
> On Thu, 12 Aug 1999, Manuel Bouyer wrote:
> > Note that the CMD0646 is a cheap but weird chip. Especially it can't use
> > both channels at the same time, access has to be serailised (that's because
> > some internal registers are shared between the 2 channels).
> I was under the impression that only the 640 had that problem. Shouldn't
> the later chips be ok?

Never tried, but from the docs I fear it's not. I even have a web page
explaining how to serialise access to the channels when using DMA.
Maybe it's ok for PIO, but do you want to use parralel PIO or serialised DMA 
accesses ?

Manuel Bouyer, LIP6, Universite Paris VI.