Can't eject CD/DVD after warm reboot?

[Michael ODonnell]

Most of our HP systems (all recent models like xw8600 and z800) refuse
to eject their optical media when the drive button is pushed after a
warm reboot following a rescue/install session booted from that drive.
Other systems (eg.  Dells) behave as we'd like when booted from those
same discs so this seems clearly to be something related to HP hardware
design or BIOS code.  This behavior is seen after using DVDs created
using the old "Timo's Rescue CD" (Debian-based w/2.4 kernel) as well
as a fairly current SysRescueCD (Gentoo-based w/2.6 kernel) configs.

Is there some trick (maybe some kernel commandline option or some program
executed during shutdown) that will leave the drive willing to eject the
media ("unlock" it?)  without us having to power-cycle these machines?

The Dell drives are IDE and the HPs are SATA - might that be relevant?

Is it the case that the HPs are working "correctly" according to some
spec and that the other systems that allow it are in fact the ones whose
behavior is b0rken?