DRI for i915 (or i81x) does not work for debian testing package version number 6.9.0.dfsg.1-4 . I do not why but it does not work:
glxinfo
...
direct rendering: no ...
It will be fixed if you use the corresponding unstable versions 6.9.0.dfsg.1-5. The following packages are enough: libglu1-xorg, libxxf86dga1, xlibmesa-dri, xlibmesa-gl, xserver-common and xserver-xorg.