VISFX_PLANE_MASK
summitfb_write4(sc, VISFX_PLANE_MASK, 0xffffffff);
summitfb_write4(sc, VISFX_PLANE_MASK, 0xff);
summitfb_write4(sc, VISFX_PLANE_MASK, 0xffffffff);
bus_space_write_stream_4(memt, memh, VISFX_PLANE_MASK, 0xffffffff);