VIDTCON0_VBPD
val = VIDTCON0_VBPD(vbpd - 1) | VIDTCON0_VFPD(vfpd - 1);
val = VIDTCON0_VBPD(vbpd - 1) |
data = VIDTCON0_VBPD(vmode->upper_margin - 1) |