| I think I found where the problem is with the cypress. I didn't read the
| doc carefuly enouth, and the DMA modes were not set (so it was using DMA
| mode 0). By the way, DMA mode config registers are in isa space, not pci
| space. Why did they do this this way ? Bah !
| 
| Could you try the new sources I've put in 
| ftp://antioche.lip6.fr/pub/tmp/bouyer/pciide.tgz ?

I'm sure Matt has provided tons of feedback, but just as an extra data-point,
I too tried this last night on my PC164SX.  Using bonnie as a metric I found
that the write-performance improved by 2 to 3 times (from 2-3Mb/s to 5-6Mb/s)
while the read-performance was basically unchanged.  Oh, I also noted the
CPU time figures for writing changed dramatically too, from 2-3% up to 98%
with your changes.  I don't know whether this helps at all, but there it is.

-- Ken

P.S. Sorry I forgot to bring the actual dmesg and output from home, but I
     also recall seeing an error about not being able to map DMA registers.