pci_enable_atomic_ops_to_root
if(pci_enable_atomic_ops_to_root(dev, PCI_EXP_DEVCAP2_ATOMIC_COMP32) &&
pci_enable_atomic_ops_to_root(dev, PCI_EXP_DEVCAP2_ATOMIC_COMP64))
int pci_enable_atomic_ops_to_root(struct pci_dev *dev, u32 cap_mask);