If I recall, that only applies to a small region in lower memory. You
are talking about vdma and I believe it was only the low meg or something
silly.
Not ALL dma uses the vdma, just the DMA addresses within the vdma region.
Furthermore, there is a single IOMMU for all the devices on the SBus,
getting you right back to the precious resource problem.
(Way back when I was involved with writing a SunOS driver for a board
my cousin built, that did direct video to a printer. I think we concluded
that scatter-gather was more practical.)
-- Steve Williams steve@icarus.com steve@picturel.com"The woods are lovely, dark and deep. But I have promises to keep, And lines to code before I sleep, And lines to code before I sleep."