CRTC_GEN_CNTL
regw(sc, CRTC_GEN_CNTL, crtc->gen_cntl | crtc->color_depth |
reg = regr(sc, CRTC_GEN_CNTL);
regw(sc, CRTC_GEN_CNTL, reg & ~(MACH64_BLANK));
reg = regr(sc, CRTC_GEN_CNTL);
regw(sc, CRTC_GEN_CNTL, reg | (MACH64_BLANK));
sc->sc_gen_cntl = regr(sc, CRTC_GEN_CNTL);