Jason,

Yes, that alignment check looks correct (16-byte boundaries).

I know that bus_dma(9) was build in part to deal with other DMA broken-ness
to do with ISA DMA controllers that couldn't address more than 16 bits, and
thus kernel low-memory bounce buffers had to be allocated for them and the
bus_dma(9) code would copy bytes around as necessary. Am I remembering
correctly?

Can't we add this class of constraint to that API?

I have the same concern for performance as Manuel, especially w.r.t.  to
dump(8). How is a user-mode program to know what buffer alignment to use?

	Erik <fair@netbsd.org>