Call for testers: Apple ATA DMA

[Nathan Whitehorn]

Peter Grehan wrote:
> Hi Nathan,
>
>> Could you try the new ata_macio.c at 
>> http://people.freebsd.org/~nwhitehorn/ata_macio.c? If that fails, 
>> also try changing sc->max_mode to WDMA2. My hardware (ata-3) won't 
>> let me test the UDMA modes, but at least the WDMA ones should now 
>> work in this configuration.
>
>  Had to drop it to WDMA2 and then the DMA i/o's completed. However, 
> the GEOM use-after-free panic persists. I'll see if I can get some 
> more info about that.
Interesting. I don't know what the panic is about, but it seems like 
programming the UDMA modes fails on the macio, Kauai, and Shasta 
controllers. I spent entirely too much time smashing my head against the 
UDMA stuff on Shasta last night with no success.

Maybe there is some MI problem where requests interact poorly with these 
controllers? As far as I know, there have never been non-PCI UDMA ATA 
controllers in the tree before.
-Nathan