ide_scsi problems in 2.4.20-pre7-ac3

I have been having problems with a Plextor CD-R connected to a PDC20268 
(Promise Ultra-100TX) using the UDMA-2 and the ide_scsi driver since the 
driver first appeared.  It's been improving, but as of 2.4.20-pre7-ac3, 
I'm still having problems.  The card is in a 33Mhz slot on a Micronics 
W6LI board.

When I write to the drive (hdg, seen as scsi ID 0) with cdrecord, it will
write successfully for some time (usually 30 MB or more, sometimes even
completing a write), whereas in older kernels it would fail between 1-4
MB.

The only log message I get is
ide_scsi: scatter/gather table too small, padding with zeroes.

and about 10 seconds later the system hangs.

Related to this is that after this happens and I restart the machine, the 
PDC20268 drivers will report timeouts resetting the card, and the only way 
to regain control of the CD-R is to power the machine down.
(I will send this in a seperate message).

Thanks.