AGP_INTEL_MCHCFG
pci_write_config(dev, AGP_INTEL_MCHCFG,
(pci_read_config(dev, AGP_INTEL_MCHCFG, 2)
reg = pci_read_config(dev, AGP_INTEL_MCHCFG, 2) & ~(1 << 9);
pci_write_config(dev, AGP_INTEL_MCHCFG, reg, 2);