[Build64R6 linux]$ git bisect bad
9393707190194eb8b42e412b444a03331db6862f is the first bad commit
commit 9393707190194eb8b42e412b444a03331db6862f
Author: Jesse Barnes <jbarnes@virtuousgeek.org>
Date:   Fri Apr 4 16:12:09 2014 -0700

    drm/i915: warn when a vblank wait times out
    
    This always indicates a bug somewhere.
    
    Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
    Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

:040000 040000 ea35b90af96d508197e845a7793f782067e7736b ac515983fd901a9b3d83c279618ab4365724dd95 M	drivers
[Build64R6 linux]$