PCI_ACS_CAP
pci_read_config_word(dev, pos + PCI_ACS_CAP, &dev->acs_capabilities);
#define INTEL_SPT_ACS_CTRL (PCI_ACS_CAP + 4)
pci_read_config_dword(dev, pos + PCI_ACS_CAP, &cap);
pci_read_config_dword(dev, pos + PCI_ACS_CAP, &cap);
pci_read_config_dword(dev, pos + PCI_ACS_CAP, &cap);
ret = pci_read_config_byte(pdev, epos + PCI_ACS_CAP, &byte);