PCI_LATENCY_TIMER
pcibios_read_config_byte(p->bus, p->devfn, PCI_LATENCY_TIMER, &pci_latency);
pcibios_write_config_byte(p->bus, p->devfn, PCI_LATENCY_TIMER, 32);
pci_read_config_byte(tp->pdev, PCI_LATENCY_TIMER, &pci_latency);
pci_write_config_byte(tp->pdev, PCI_LATENCY_TIMER, 64);