Call for testers: Apple ATA DMA

[Nathan Whitehorn]

I just finished a patch to the Apple built-in ATA drivers (ata_macio and 
ata_kauai) that adds DMA support. Due to lack of Kauai hardware (G4 
machines), it has had only minimal testing, so I'd appreciate some more.

WARNING: THIS MAY DO HORRIBLE THINGS LIKE ERASE YOUR HARD DRIVE

The patch can be found here: 
http://people.freebsd.org/~nwhitehorn/apple-ata-dma.patch

DMA modes on Kauai are currently slower than they should be because of 
an interrupt handling problem. DBDMA completion interrupts arrive on a 
different interrupt vector than the regular ATA interrupts, so we need 
to bind to the second vector as well. However, attaching a PCI device to 
more than one IRQ makes the PCI bus driver think the second interrupt is 
an MSI. Since it isn't, the PCI bus module then helpfully panics. This 
should be fixed somehow.
-Nathan