PCI: Preserve MPS and MRRS when applying _HPX settings

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>

diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index 1ff2105..cb411fb 100644 (file)
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -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);