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
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -1301,6 +1301,16 @@
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);