From: Yazen Ghannam <yazen.ghannam@xxxxxxx> Currently, aer_service_init() checks if AER is available and that Firmware First handling is not enabled. The _OSC request for AER is not taken into account when deciding to enable AER in Linux. >From ACPI 6.2 Section 6.2.11.3, "If any bits in the Control Field are returned cleared (masked to zero) by the _OSC control method, the respective feature is designated unsupported by the platform and must not be enabled by the OS." The OS and the Platform should agree that the OS can have control of AER otherwise we should disable AER in the OS. Mark AER as disabled if the _OSC request was not made or accepted. This covers two cases where the OS and Platform disagree: 1) The OS requests AER control and Platform denies the request. 2) The OS does not request AER control but the Platform returns the AER control bit set, possibly due to a Firmware bug. The _OSC control for AER is not requested when APEI Firmware First is used, so the same condition applies from case 2 above. Remove redundant check for aer_acpi_firmware_first() when calling aer_service_init(), since this check is already included when checking the _OSC control. Signed-off-by: Yazen Ghannam <yazen.ghannam@xxxxxxx> --- Link: https://lkml.kernel.org/r/20180111150316.19951-1-Yazen.Ghannam@xxxxxxx v1->v2: * Expand commit message. * Add Spec reference to commit message. * Fix spelling error in commit message. * Add comment for 3-way bitwise AND. drivers/acpi/pci_root.c | 7 +++++++ drivers/pci/pcie/aer/aerdrv.c | 2 +- 2 files changed, 8 insertions(+), 1 deletion(-) diff --git a/drivers/acpi/pci_root.c b/drivers/acpi/pci_root.c index 6fc204a52493..ab0192fd24c7 100644 --- a/drivers/acpi/pci_root.c +++ b/drivers/acpi/pci_root.c @@ -512,6 +512,13 @@ static void negotiate_os_control(struct acpi_pci_root *root, int *no_aspm) */ *no_aspm = 1; } + + /* + * We can use a 3-way bitwise AND to check that the AER control bit is + * both requested by the OS and granted by the Platform. + */ + if (!(requested & control & OSC_PCI_EXPRESS_AER_CONTROL)) + pci_no_aer(); } static int acpi_pci_root_add(struct acpi_device *device, diff --git a/drivers/pci/pcie/aer/aerdrv.c b/drivers/pci/pcie/aer/aerdrv.c index 6ff5f5b4f5e6..39bb059777d0 100644 --- a/drivers/pci/pcie/aer/aerdrv.c +++ b/drivers/pci/pcie/aer/aerdrv.c @@ -374,7 +374,7 @@ static void aer_error_resume(struct pci_dev *dev) */ static int __init aer_service_init(void) { - if (!pci_aer_available() || aer_acpi_firmware_first()) + if (!pci_aer_available()) return -ENXIO; return pcie_port_service_register(&aerdriver); } -- 2.14.1 -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
