CVT_MIN_V_BPORCH
if (vbilines < (CVT_RB_VFPORCH + vsync + CVT_MIN_V_BPORCH))
vbilines = CVT_RB_VFPORCH + vsync + CVT_MIN_V_BPORCH;
if (v_bp < CVT_MIN_V_BPORCH)
v_bp = CVT_MIN_V_BPORCH;