HACTIVE
value = FIELD_PREP(HACTIVE, hactive) | FIELD_PREP(HBLANK, hblank);
HACTIVE(hactive - 1) | HTOTAL(htotal - 1));
HACTIVE(adjusted_mode->crtc_hdisplay - 1) |
HACTIVE(640 - 1) | HTOTAL(800 - 1));