intel_crtc_scanline_offset
intel_crtc_scanline_offset(pipe_config));
return (scanline + vtotal - intel_crtc_scanline_offset(crtc_state)) % vtotal;
crtc->scanline_offset = intel_crtc_scanline_offset(crtc_state);
int intel_crtc_scanline_offset(const struct intel_crtc_state *crtc_state);