I am seeing a rendering error in morph3d, most of the faces of the 3D morphing object are solid white, or not properly shaded. I have a screenshot of the error in morph3d at http://www.spacey.net/andrewm/morph3d.png. The only other program that exhibits this problem is Tux Racer (http://tuxracer.sourceforge.net), but in Tux Racer only the penguin model is affected. The terrain is rendered correctly. Apologies if I have submitted this bug twice, it appeared not to have submitted the first time. I am using a G400 Max and DRI built from a fresh checkout this morning.
I also see this with a Rage128 Mobility M3 in a Powerbook. Must say that in general things look much better than before the tdfx-2-1 merge.
In mga_xmesa.c find the line that says
DD_LIGHTING_CULL
and remove it. This should fix your problem.