(In reply to comment #11)
> X won't start without LIBGL_ALWAYS_SOFTWARE set.  Log file is Xort.0.log.sav
> above.

That doesn't show any problem. Maybe check the display manager (lightdm?) log
files to see if the X server stderr contains more information.

Meanwhile, you could let it set LIBGL_ALWAYS_SOFTWARE to get into X, then run
unity_support_test something like this:

( unset LIBGL_ALWAYS_SOFTWARE; /usr/lib/nux/unity_support_test -p )

> Radeon 9600 vs. 9550?

Just two different marketing names for the same hardware.

> Not sure anybody needs to run Xorg -configure anymore, [...]

Nobody does. It's been deprecated and barely working for a long time.