options i915 modeset=1
, and also added sections to /etc/X11/xorg.conf from the defaults created from X -configure:
Viewport 0 0EndSubSection
You would of course set this for whatever your native resolution is.
Note that I don't use the intel driver, but leave it at fbdev.
This causes an ugly (but high-res!) black screen after starting up, but after you startx, everything looks good.
It's a hack, must be that loading the i915 driver sets up the timing in the chip that fbdev uses. The optimal fix would be to have the intel driver in X work and be able to detect the screen resolution.