Call for testers: Apple ATA DMA

[Marco Trillo]

Hi,

On Tue, Sep 23, 2008 at 7:54 PM, Nathan Whitehorn
<nwhitehorn at freebsd.org> wrote:
>> It improves things, but it's still not good:
>
> [Smacking forehead]
>
> The Kauai/MacIO controller cannot support multiple modes of the same class
> (DMA/PIO) simultaneously on the same bus for different devices. You have to
> reprogram the timing register whenever you select a new device...
>
> Ways to check if this is the problem:
> 1) Limit devices to UDMA33.
> 2) Disable DMA on acd0.
>
> Our ATA stack doesn't seem to support a hook for doing things on a device
> select, so I'm not sure how to fix this.

The NetBSD driver seems to solve this by configuring the timing
register when starting the DMA transfer, but I'm not sure if this is
the correct fix...

Regards,
Marco.