PCI: Preserve MPS and MRRS when applying _HPX settings
authorBjorn Helgaas <bhelgaas@google.com>
Wed, 3 Sep 2014 19:26:29 +0000 (13:26 -0600)
committerBjorn Helgaas <bhelgaas@google.com>
Sat, 13 Sep 2014 02:11:41 +0000 (20:11 -0600)
Linux manages MPS and MRRS settings to keep them consistent across the PCIe
fabric.  BIOS doesn't participate in this Linux management, so ignore that
part of any _HPX settings it supplies.

Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Yinghai Lu <yinghai@kernel.org>
drivers/pci/probe.c

index 1ff2105ba401e2bfd6afdf9feac52dc1502d2025..cb411fbb6435ed08e00f2f2311af623e20d0c021 100644 (file)
@@ -1301,6 +1301,16 @@ static void program_hpp_type2(struct pci_dev *dev, struct hpp_type2 *hpp)
                return;
        }
 
+       /*
+        * Don't allow _HPX to change MPS or MRRS settings.  We manage
+        * those to make sure they're consistent with the rest of the
+        * platform.
+        */
+       hpp->pci_exp_devctl_and |= PCI_EXP_DEVCTL_PAYLOAD |
+                                   PCI_EXP_DEVCTL_READRQ;
+       hpp->pci_exp_devctl_or &= ~(PCI_EXP_DEVCTL_PAYLOAD |
+                                   PCI_EXP_DEVCTL_READRQ);
+
        /* Initialize Device Control Register */
        pcie_capability_clear_and_set_word(dev, PCI_EXP_DEVCTL,
                        ~hpp->pci_exp_devctl_and, hpp->pci_exp_devctl_or);