On May 31, 2007, at 7:58 AM, Izumi Tsutsui wrote:
> The MI SONIC driver (sys/dev/ic/dp83932.c) should have better
> performance than -current mac68k homegrown version because
> the former does direct DMA from/to mbufs and less memory copies.

This is probably a good thing because using the MI driver's DMA is  
something you've actually got working. Theoretically, though, the on- 
board DMA engine on the AV should also be able to DMA to the mbufs  
directly, assuming they meet the appropriate alignment constraints, etc.

I would have to imagine there is some good reason to use the onboard  
DMA over the Sonic's DMA, if only because Apple engineers would have  
been aware of the Sonic's DMA engine and they could have saved ASIC  
space on the PSC if they could have relied on the the Sonic to push  
the data. Why bother with more DMA channels if you don't need them?

Good work, though!