I want my computer to automatically disable polling of the CD drive when I
switch to battery power; and re-enable it when I come back.
To achieve this, I think I have to use the "Configuration Notifications"
feature of kpowersave (I use KDE) and add a shell script to be run when AC
power comes and goes, which calls hal-disable-polling.
However, hal-disable-polling doesn't allow non-root users, whether logged in
or not, to access it:
$ hal-disable-polling --device /dev/scd0
This program requires super user (root) privileges.
I think that that access check is too restrictive - the logged in user should
be allowed to control polling of the drive.
This works already, see hal-lock(1). Besides, feature requests should not be
filed in a downstream bugzilla.