INTEL_I820_RDCR
pci_read_config_byte(agp_bridge->dev, INTEL_I820_RDCR, &temp);
pci_write_config_byte(agp_bridge->dev, INTEL_I820_RDCR,
pci_read_config_byte(agp_bridge->dev, INTEL_I820_RDCR, &temp2);
pci_write_config_byte(agp_bridge->dev, INTEL_I820_RDCR, temp2 | (1 << 1));