vblanktimestamp
timeval_to_ns(&vblanktimestamp(dev, crtc, vblcount));
timeval_to_ns(&vblanktimestamp(dev, crtc, vblcount));
vblanktimestamp(dev, crtc, vblcount + 1) = tvblank;
*vblanktime = vblanktimestamp(dev, crtc, cur_vblank);
vblanktimestamp(dev, crtc, tslot) = t_vblank;