AGP_INTEL_NBXCFG
reg = pci_conf_read(sc->as_pc, sc->as_tag, AGP_INTEL_NBXCFG);
pci_conf_write(sc->as_pc, sc->as_tag, AGP_INTEL_NBXCFG, reg);
reg = pci_conf_read(sc->as_pc, sc->as_tag, AGP_INTEL_NBXCFG);
pci_conf_write(sc->as_pc, sc->as_tag, AGP_INTEL_NBXCFG, reg);