Bug#359328:

[Mateusz Kaduk]

AIGLX: 3D driver claims to not support visual 0x23 

If you have direct rendering enabled and Your screen blinks with black
triangles
Warning message:

(WW) AIGLX: 3D driver claims to not support visual 0x23
in /var.log/Xorg.0.log means that i912_dri.so is lacking of something.

I found that Xorg is looking first in /usr/X11R6/lib/modules/dri whereas
new is in /usr/lib/dri

ln -s /usr/lib/dri /usr/X11R6/lib/modules/dri
Should fix the problem