static int pci_quirk_cavium_acs(struct pci_dev *dev, u16 acs_flags)
 {
        /*
-        * Cavium devices matching this quirk do not perform peer-to-peer
-        * with other functions, allowing masking out these bits as if they
-        * were unimplemented in the ACS capability.
+        * Cavium root ports don't advertise an ACS capability.  However,
+        * the RTL internally implements similar protection as if ACS had
+        * Request Redirection, Completion Redirection, Source Validation,
+        * and Upstream Forwarding features enabled.  Assert that the
+        * hardware implements and enables equivalent ACS functionality for
+        * these flags.
         */
-       acs_flags &= ~(PCI_ACS_SV | PCI_ACS_TB | PCI_ACS_RR |
-                      PCI_ACS_CR | PCI_ACS_UF | PCI_ACS_DT);
+       acs_flags &= ~(PCI_ACS_RR | PCI_ACS_CR | PCI_ACS_SV | PCI_ACS_UF);
 
        if (!((dev->device >= 0xa000) && (dev->device <= 0xa0ff)))
                return -ENOTTY;