Normally, in Kubuntu, after pressing one of the laptop's volume-control keys (volume-up, volume-down, or mute), a gray box appears on the screen listing the current level of the volume. The volume level is also automatically adjusted in kmix to match.
If I open System Settings -> Regional & Language -> Keyboard Layout -> Xkb Options, and select Enable xkb options, then the effect of these volume keys will be different the next time that the system is restarted. The volume keys will still affect the level of the volume (pressing volume-up still raises the volume, volume-down still lowers it, and mute still mutes it), but the gray box no longer appears, and the changes in volume are not reflected in kmix. Instead, the volume level in kmix can be adjusted independently from the hardware volume level.
I am running Kubuntu 7.04, but this bug also existed in Kubuntu 6.10. I am using an IBM X41 Tablet computer, and I have heard from one other user who experienced the same problem while using a regular IBM X41 laptop.
Is this symptom still reproducible in 8.10 beta or later? (I can't reproduce this on an X41-2527.)