AGP_I965_PGTBL_CTL2
pgetbl_ctl2 = bus_read_4(sc->sc_res[0], AGP_I965_PGTBL_CTL2);
bus_write_4(sc->sc_res[0], AGP_I965_PGTBL_CTL2, pgetbl_ctl2);
bus_read_4(sc->sc_res[0], AGP_I965_PGTBL_CTL2));