The normal drawing path does this, and it's necessary on Ivybridge, so let's try it on Sandybridge too. It's not explicitly documented as necessary, but might help with hangs. Signed-off-by: Kenneth Graunke <kenneth@whitecape.org> Tested-by: Xinkai Chen <yeled.nova@gmail.com> Reviewed-by: Eric Anholt <eric@anholt.net> Cc: "9.2" <mesa-stable@lists.freedesktop.org>