X4.0.2 and SaX2 and Silicon Motion SM720 Lynx3DM

I've got an HP pavilion laptop with the above chipset. When I try to run SaX2 or xf86cfg the screen goes blank and I have to reboot to get it back. I'm Xless. Anyone know the trick for this chipset? -- Mark Hounschell markh@compro.net