Fixes https://bugs.freedesktop.org/show_bug.cgi?id=29141 though the
workaround itself is still a bit of a mystery.
Tested-by: NAdam Hill <sidepipeuk@yahoo.co.uk>
Signed-off-by: NJesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: NEric Anholt <eric@anholt.net>