[Soekris] 4801 CF, NetBSD-current

[Bernd Walter]

On Wed, Oct 20, 2004 at 09:34:18AM +0100, Chris Boot wrote:
> It sounds a lot to me like problems with DMA, rather than the card 
> itself. Try disabling DMA on the CF card at boot time. There was a post 
> about this a few weeks back about this, and your CF card even rings a 
> bell (the other was a SanDisk as well). AFAIK CF cards usually work via 
> PIO anyway.

The story behind DMA is that originally CF cards didn't support DMA
and the specification had no wiring defined for DMA.
Now there is a DMA specification and modern cards tend to support it
as well.
Now we end up with an IDE controller and a media that are both DMA
capable, but without DMA wiring and an OS that doesn't know about
the bad wiring.
Modern SanDisk medias support DMA and you can buy them with DMA
feature reporting enabled or disabled - IIRC you get get a tool from
them to switch as well - that is why same looking media behave
diffferent.

-- 
B.Walter                   BWCT                http://www.bwct.de
bernd at bwct.de                                  info at bwct.de