The Intel driver 2.0 brings RandR 1.2 support, enabling dynamic multiple heads configuration. Some old Xinerama/dual-head configs cause the server to crash at startup. Basically, the new driver only supports the new config syntax, and it might not ever get fixed.
To solve this problem, you need to update your /etc/X11/xorg.conf:
- drop dual Device/Screen/Monitor sections, keep a single one
- drop MonitorLayout option and Screen lines from the remaining Device section
- drop dual Screen lines from the ServerLayout section
- drop RightOf/LeftOf indication to the remaining Screen line in ServerLayout section
- add a Virtual 2048 2048 line in SubSection "Display" to create a large virtual screen where physical monitor will be placed (note that boards <= i945 will disable DRI if you use more than 2048 in one direction)
- use xrandr --output VGA --right-of LVDS to place you VGA screen on the right of your internal LCD (see xrandr manpage for details)
Note that other driver are being ported to RandR-1.2 (nv 2.1 for G80, ati and mga coming soon), so the bug might be non-Intel specific in the near future.