From: Bjorn Helgaas bhelgaas@google.com
When booting with "pci=noaer", we don't request control of AER, but we previously *did* request control of DPC, as in the dmesg log attached at the bugzilla below:
Command line: ... pci=noaer acpi PNP0A08:00: _OSC: OS supports [ExtendedConfig ASPM ClockPM Segments MSI EDR HPX-Type3] acpi PNP0A08:00: _OSC: OS now controls [PCIeHotplug SHPCHotplug PME PCIeCapability LTR DPC]
That's illegal per PCI Firmware Spec, r3.3, sec 4.5.1, table 4-5, which says:
If the operating system sets this bit [OSC_PCI_EXPRESS_DPC_CONTROL], it must also set bit 7 of the Support field (indicating support for Error Disconnect Recover notifications) and bits 3 and 4 of the Control field (requesting control of PCI Express Advanced Error Reporting and the PCI Express Capability Structure).
Request DPC control only if we have also requested AER control.
Fixes: ac1c8e35a326 ("PCI/DPC: Add Error Disconnect Recover (EDR) support") Link: https://bugzilla.kernel.org/show_bug.cgi?id=218491#c12 Signed-off-by: Bjorn Helgaas bhelgaas@google.com Cc: stable@vger.kernel.org # v5.7+ Cc: Kuppuswamy Sathyanarayanan sathyanarayanan.kuppuswamy@linux.intel.com Cc: Matthew W Carlis mattc@purestorage.com Cc: Keith Busch kbusch@kernel.org Cc: Lukas Wunner lukas@wunner.de Cc: Mika Westerberg mika.westerberg@linux.intel.com Cc: Jesse Brandeburg jesse.brandeburg@intel.com --- drivers/acpi/pci_root.c | 20 +++++++++++--------- 1 file changed, 11 insertions(+), 9 deletions(-)
diff --git a/drivers/acpi/pci_root.c b/drivers/acpi/pci_root.c index 58b89b8d950e..efc292b6214e 100644 --- a/drivers/acpi/pci_root.c +++ b/drivers/acpi/pci_root.c @@ -518,17 +518,19 @@ static u32 calculate_control(void) if (IS_ENABLED(CONFIG_HOTPLUG_PCI_SHPC)) control |= OSC_PCI_SHPC_NATIVE_HP_CONTROL;
- if (pci_aer_available()) + if (pci_aer_available()) { control |= OSC_PCI_EXPRESS_AER_CONTROL;
- /* - * Per the Downstream Port Containment Related Enhancements ECN to - * the PCI Firmware Spec, r3.2, sec 4.5.1, table 4-5, - * OSC_PCI_EXPRESS_DPC_CONTROL indicates the OS supports both DPC - * and EDR. - */ - if (IS_ENABLED(CONFIG_PCIE_DPC) && IS_ENABLED(CONFIG_PCIE_EDR)) - control |= OSC_PCI_EXPRESS_DPC_CONTROL; + /* + * Per PCI Firmware Spec, r3.3, sec 4.5.1, table 4-5, the + * OS can request DPC control only if it has advertised + * OSC_PCI_EDR_SUPPORT and requested both + * OSC_PCI_EXPRESS_CAPABILITY_CONTROL and + * OSC_PCI_EXPRESS_AER_CONTROL. + */ + if (IS_ENABLED(CONFIG_PCIE_DPC)) + control |= OSC_PCI_EXPRESS_DPC_CONTROL; + }
return control; }