diff options
Diffstat (limited to 'arch/x86/pci/fixup.c')
| -rw-r--r-- | arch/x86/pci/fixup.c | 40 |
1 files changed, 40 insertions, 0 deletions
diff --git a/arch/x86/pci/fixup.c b/arch/x86/pci/fixup.c index e7e71490bd25..25076a5acd96 100644 --- a/arch/x86/pci/fixup.c +++ b/arch/x86/pci/fixup.c @@ -295,6 +295,46 @@ DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_MCH_PC, pcie_ro DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_MCH_PC1, pcie_rootport_aspm_quirk); /* + * PCIe devices underneath Xeon 6 PCIe Root Port bifurcated to x2 have lower + * performance with Extended Tags and MRRS > 128B. Work around the performance + * problems by disabling Extended Tags and limiting MRRS to 128B. + * + * https://cdrdv2.intel.com/v1/dl/getContent/837176 + */ +static int limit_mrrs_to_128(struct pci_host_bridge *b, struct pci_dev *pdev) +{ + int readrq = pcie_get_readrq(pdev); + + if (readrq > 128) + pcie_set_readrq(pdev, 128); + + return 0; +} + +static void pci_xeon_x2_bifurc_quirk(struct pci_dev *pdev) +{ + struct pci_host_bridge *bridge = pci_find_host_bridge(pdev->bus); + u32 linkcap; + + pcie_capability_read_dword(pdev, PCI_EXP_LNKCAP, &linkcap); + if (FIELD_GET(PCI_EXP_LNKCAP_MLW, linkcap) != 0x2) + return; + + bridge->no_ext_tags = 1; + bridge->enable_device = limit_mrrs_to_128; + pci_info(pdev, "Disabling Extended Tags and limiting MRRS to 128B (performance reasons due to x2 PCIe link)\n"); +} + +DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_INTEL, 0x0db0, pci_xeon_x2_bifurc_quirk); +DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_INTEL, 0x0db1, pci_xeon_x2_bifurc_quirk); +DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_INTEL, 0x0db2, pci_xeon_x2_bifurc_quirk); +DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_INTEL, 0x0db3, pci_xeon_x2_bifurc_quirk); +DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_INTEL, 0x0db6, pci_xeon_x2_bifurc_quirk); +DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_INTEL, 0x0db7, pci_xeon_x2_bifurc_quirk); +DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_INTEL, 0x0db8, pci_xeon_x2_bifurc_quirk); +DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_INTEL, 0x0db9, pci_xeon_x2_bifurc_quirk); + +/* * Fixup to mark boot BIOS video selected by BIOS before it changes * * From information provided by "Jon Smirl" <jonsmirl@gmail.com> |