PCI_LEGSUP_USBPIRQDEN
pci_write_config(self, PCI_LEGSUP, PCI_LEGSUP_USBPIRQDEN, 2);
if (pci_read_config(self, PCI_LEGSUP, 2) != PCI_LEGSUP_USBPIRQDEN) {
pci_write_config(self, PCI_LEGSUP, PCI_LEGSUP_USBPIRQDEN, 2);
pci_write_config(self, PCI_LEGSUP, PCI_LEGSUP_USBPIRQDEN, 2);