This is from bug 25728.

[airlied: I'm just forwarding the patch for review, Thomas, ickle?]
Acked-by: NJerome Glisse <jglisse@redhat.com>
Acked-by: NThomas Hellstrom <thellstrom@vmware.com>
Signed-off-by: NDave Airlie <airlied@redhat.com>