The earlier production runs of the XE had sound onboard, but bugs in UBoot prevented it from being initialized properly. Those bugs were later worked around in
this driver, but not before the onboard sound was written off as hopeless and the chip was removed from later productions.
So if you've lucky enough to have an older board with the chip, just install that driver and off you go.
Assuming Hyperion ever gets around to fixing UBoot, onboard sound should work under Linux as well.
