The macros PCI_EXP_LNKCAP_SLS_*GB are values, not bit masks. We must mask the register and compare it against them. This patch fixes errors "amdgpu: [powerplay] failed to send message 261 ret is 0" errors when PCIe-v3 card is plugged into PCIe-v1 slot, because the slot is being incorrectly reported as PCIe-v3 capable. Signed-off-by: Mikulas Patocka <mpatocka@xxxxxxxxxx> Fixes: 6cf57be0f78e ("PCI: Add pcie_get_speed_cap() to find max supported link speed") Cc: stable@xxxxxxxxxxxxxxx # v4.17+ --- drivers/pci/pci.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) Index: linux-4.19/drivers/pci/pci.c =================================================================== --- linux-4.19.orig/drivers/pci/pci.c 2018-10-30 16:58:58.000000000 +0100 +++ linux-4.19/drivers/pci/pci.c 2018-10-30 16:58:58.000000000 +0100 @@ -5492,13 +5492,13 @@ enum pci_bus_speed pcie_get_speed_cap(st pcie_capability_read_dword(dev, PCI_EXP_LNKCAP, &lnkcap); if (lnkcap) { - if (lnkcap & PCI_EXP_LNKCAP_SLS_16_0GB) + if ((lnkcap & PCI_EXP_LNKCAP_SLS) == PCI_EXP_LNKCAP_SLS_16_0GB) return PCIE_SPEED_16_0GT; - else if (lnkcap & PCI_EXP_LNKCAP_SLS_8_0GB) + else if ((lnkcap & PCI_EXP_LNKCAP_SLS) == PCI_EXP_LNKCAP_SLS_8_0GB) return PCIE_SPEED_8_0GT; - else if (lnkcap & PCI_EXP_LNKCAP_SLS_5_0GB) + else if ((lnkcap & PCI_EXP_LNKCAP_SLS) ==PCI_EXP_LNKCAP_SLS_5_0GB) return PCIE_SPEED_5_0GT; - else if (lnkcap & PCI_EXP_LNKCAP_SLS_2_5GB) + else if ((lnkcap & PCI_EXP_LNKCAP_SLS) == PCI_EXP_LNKCAP_SLS_2_5GB) return PCIE_SPEED_2_5GT; }