CDROM hangs on unmount on 5.0.1

[George Harvey <fr30%dial.pipex.com@localhost>]

Hi,

I'm seeing system hangs when accessing the CDROM on my Ultra 5 running
5.0.1 GENERIC. The CDROM is the original Sun drive attached to the
internal IDE controller:

cd0 at atapibus0 drive 0: <CRD-8322B, 2000/07/02, 1.06> cdrom removable
cd0: drive supports PIO mode 4, DMA mode 2
cd0(cmdide0:1:0): using PIO mode 4, DMA mode 2 (using DMA)

I can mount a CD, and copy files to the local hard disk, but when I
unmount it, the system becomes unresponsive for several minutes and I
see messages like this on the console:

wdc_atapi_intr: bad data phase DATAOUT
cmdide0:1:0: reset failed
cmdide0:1:0: unbusy timed out
cmdide0:1:0: reset failed
cmdide0:1:0: unbusy timed out

The umount command eventually times out but after that the CDROM drive
remains unusable until I reboot the machine. The software eject command
hangs and the eject button on the drive is ignored.

A search on Google shows similar errors reported on Blade 100 machines
but I understand that they use a different IDE controller chip so I
don't know if the errors are related.

George