Comment 4 for bug 698120

In /var/log/kern.log I get a long sequence of:

[drm:i915_gem_mmap_gtt_ioctl] *ERROR* Attempting to mmap a purgeable buffer

that ends up finally with a

[drm:i915_gem_object_bind_to_gtt] *ERROR* Attempting to bind a purgeable object

then X freezes