horrible system performance using ide-scsi for cdrom on tibook

[rob pfile <pfile@riverstonenet.com>]

I've posted on a similar topic before. the short story is that i could
not make the dvd/cdrom drive in the tibook work for audio extraction
unless i used the ide-scsi package.

while that worked in the sense that cdparanoia could see the drive,
system performance during cd ripping is terrible. the load average goes
to about 5 and the mouse is completely unusable. the strange thing is
that the X server and a few X clients are hogging the cpu during
ripping, which just makes no sense.

i had enabled ide-scsi on my desktop machine (G4/500 "agp graphics" with
the DVD-ram drive) thinking that it was necessary, and had the same
performance problems. i just rebooted
without it and found that cdparanoia could find the drive and extract
audio just fine in ATAPI mode, and that system performance was otherwise
normal (aside from cdparanoia hogging the CPU :)

so i tried the tibook again without ide-scsi and cdparanoia -vsQ
reports (and yes there is a disc in the drive):

004: Unable to read table of contents header
Unable to open disc. Is there an audio CD in the drive?

this must be the original error i got which prompted me to try ide-scsi.

so i have two questions for the lists now:

1) is the MATSHITA DVD-ROM SR-8187 in the tibook somehow just
   incompatible with the ide-cd driver? anyone know?

2) do other people experience the same bad system performance with
   ide-scsi during cd rips? i can only guess that there's something
   wrong with that driver that's passing a bunch of interrupts to
   the X server somehow, which is causing the X server to ask for
   redraws or something on all its clients.

kernel is benh 2.4.3 (tibook) and benh-2.4.8-pre7 (g4/500),
cdparanoia III release 9.8

ideas?

thanks

rob