Vanilla kernel 2.6.26.2 (no GEM support in the kernel DRM module).
Everything else (xserver, mesa, drm userspace library, intel driver) from git master branches.

Steps to reproduce:

1) start the xserver
2) start compiz
3) kill compiz
[xserver restarts, prints this into tho log file:
(EE) [drm] Could not set DRM device bus ID.
(EE) intel(0): [dri] DRIScreenInit failed. Disabling DRI.
]
4) start xterm
5) run glxinfo

xserver crashes with:

Backtrace:
0: /opt/xorg/bin/Xorg(xf86SigHandler+0x67) [0x480f17]
1: /lib/libc.so.6 [0x7ff5b10a95a0]
2: /opt/xorg/lib/xorg/modules/extensions//libdri.so(DRIBlockHandler+0x42) [0x7ff5b05cac92]
3: /opt/xorg/lib/xorg/modules/extensions//libglx.so(__glXleaveServer+0x18) [0x7ff5b080c738]
4: /opt/xorg/lib/xorg/modules/extensions//libglx.so [0x7ff5b080cbed]
5: /opt/xorg/bin/Xorg(Dispatch+0x2b9) [0x44c4a9]
6: /opt/xorg/bin/Xorg(main+0x3b5) [0x4331b5]
7: /lib/libc.so.6(__libc_start_main+0xf4) [0x7ff5b10964a4]
8: /opt/xorg/bin/Xorg [0x4326b9]

Fatal server error:
Caught signal 11.  Server aborting


or this:

Backtrace:
0: /opt/xorg/bin/Xorg(xf86SigHandler+0x67) [0x480f17]
1: /lib/libc.so.6 [0x7f486553a5a0]
2: /lib/libc.so.6 [0x7f486584caa0]

Fatal server error:
Caught signal 11.  Server aborting