> Well, for "simple but probably completely undocumented", there's the
> control panel Toshiba used on their Infinia series of computers, it's got
> a few buttons, a knob, and (on some models) an LCD panel.  It's actually one
> of the best USB hacks I've seen; you can play CD's on a machine without
> waking up the display, and you have a software volume knob, and... it's
> pretty cool.
> 
> I doubt it helps, though, but I'd love to have a driver for one.
Actually, if Toshiba has any kind of sense this will be a HID
(Human Interface Device) which means that it the most well documented
of all device types.  Upon query it will tell you exactly what buttons
and displays it has so the generic HID driver can take care of it.
Unfortunately, I don't have a generic HID driver yet. ;-)

If you've got one of those machines you could take my driver
(if the USB host controller is UHCI) and check if it is a HID.

> I believe there are USB keyboards, mice, and scanners now.  I don't know
> if you actually have to write a driver for them, or if the BIOS notices them
> and turns them into a "regular" device through some black magic.
BIOS can magically transform keyboards and mice into normal looking
devices, but as soon as you OS takes over the host controller the magic
disappears (I would imagine it disappears when the OS takes over
interrupt vectoring as well).

        -- Lennart