X can work just fine without drm on cards which have thier own memory.
However, it uses drm to steal more memory on intel cards (and probably
any shared memory cards).
As the stolen memory is reported just below 8M it is somewhat low, and
you might not be able to use the full resolution of the display (and
would have to set the Virtual to low enough size for X to start in
that case).
Even if you can use the built-in display X will likely fail to start
if you connect some plain 17" display to the VGA connector.