I've no idea why, but a solution might be to copy over the XF86Config-4 for one of the versions which works.
Just curious why my screen goes black after x is started
This happens with both 3.8.1 and 3.4 but 3.1 works ok.
Whats strange is knoppix correctly identifies my video card & monitor & the screen reolutions the monitor supports yet unless I use the frame buffer cheat codes I get black screen. I also noted the help sez the fb are for laptops & this is on a gateway desktop
I've no idea why, but a solution might be to copy over the XF86Config-4 for one of the versions which works.

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