Curt Sampson writes:

>"It depends." It depends a lot on how much work you care to do.
>The DMA engines in the 590, 905A and 905B are all somewhat different.


The DMA engine in the Vortex (59x) cards just isn't very useful.  It
still requires an interrupt for each packet, and given the constraints
(at most one DMA transfer active at any one time), it's never seemed
worthwhile to add. (It's been a while since i read the manual, but
ISTR the DMA engine itself was half-duplex: it can you if a receive
DMA was pending you couldn't do a transmit dma, and vice-versa.)

I havent tracked numbers for some time, but on teh Intel Endeavour
(P5/133) sysetms I used, the PIO-based NetBSD driver worked out faster
on the same hardware than the Linux driver (which did use DMA for
receive-side packets.)

I dont have a Cyclone or I'd cons up a driver (I do have the docs.)