On Mon, 8 Apr 2002, Michael R. Zucca wrote:
> I am. I already have code which does the DMA into a bounce-buffer. However,
> this doesn't offer much of a speed up because of the extra bcopy. What I'd

That seems a bit surprising to me... the MACE driver does an extra copy
too (which I had looked into fixing, but didn't really have the time),
and it manages to get around 800K/s throughput.  IIRC, the current esp
driver on an AV only manages around 300K/s.

Does using DMA alleviate the massive loss of clock interrupts though?
That by itself would be great, even if it didn't significantly speed up
SCSI transfers...

> like to do is to get the bus_dma() infrastructure in place and have the dma
> engine read/write directly into the destination memory.

bus_dma() would be cool :) I'll convert the mc driver over to use
bus_dma when it's available...