Comment 72 for bug 727594

Working on the theory that it is one and the same bug:

commit b5b5ac2dec49ea5ae033434efa90863aa5cdfb2c
Author: Chris Wilson <email address hidden>
Date: Thu Mar 17 15:23:22 2011 +0000

    drm/i915: Fix tiling corruption from pipelined fencing

    ... even though it was disabled. A mistake in the handling of fence reuse
    caused us to skip the vital delay of waiting for the object to finish
    rendering before changing the register.

    Cc: Andy Whitcroft <email address hidden>
    Cc: Daniel Vetter <email address hidden>
    Reviewed-by: Daniel Vetter <email address hidden>
    [Note for 2.6.38-stable, we need to reintroduce the interruptible passing]
    Signed-off-by: Chris Wilson <email address hidden>
    Tested-by: Dave Airlie <email address hidden>