From: Kuppuswamy Sathyanarayanan sathyanarayanan.kuppuswamy@linux.intel.com
[ Upstream commit c441b1e03da6c680a3e12da59c554f454f2ccf5e ]
During EDR recovery, the OS must clear error status of the port that triggered DPC even if firmware retains control of DPC and AER (see the implementation note in the PCI Firmware spec r3.3, sec 4.6.12).
Prior to 068c29a248b6 ("PCI/ERR: Clear PCIe Device Status errors only if OS owns AER"), the port Device Status was cleared in this path:
edr_handle_event dpc_process_error(dev) # "dev" triggered DPC pcie_do_recovery(dev, dpc_reset_link) dpc_reset_link # exit DPC pcie_clear_device_status(dev) # clear Device Status
After 068c29a248b6, pcie_do_recovery() no longer clears Device Status when firmware controls AER, so the error bit remains set even after recovery.
Per the "Downstream Port Containment configuration control" bit in the returned _OSC Control Field (sec 4.5.1), the OS is allowed to clear error status until it evaluates _OST, so clear Device Status in edr_handle_event() if the error recovery was successful.
[bhelgaas: commit log] Fixes: 068c29a248b6 ("PCI/ERR: Clear PCIe Device Status errors only if OS owns AER") Link: https://lore.kernel.org/r/20230315235449.1279209-1-sathyanarayanan.kuppuswam... Reported-by: Tsaur Erwin erwin.tsaur@intel.com Signed-off-by: Kuppuswamy Sathyanarayanan sathyanarayanan.kuppuswamy@linux.intel.com Signed-off-by: Bjorn Helgaas bhelgaas@google.com Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/pci/pcie/edr.c | 1 + 1 file changed, 1 insertion(+)
diff --git a/drivers/pci/pcie/edr.c b/drivers/pci/pcie/edr.c index a6b9b479b97ad..87734e4c3c204 100644 --- a/drivers/pci/pcie/edr.c +++ b/drivers/pci/pcie/edr.c @@ -193,6 +193,7 @@ static void edr_handle_event(acpi_handle handle, u32 event, void *data) */ if (estate == PCI_ERS_RESULT_RECOVERED) { pci_dbg(edev, "DPC port successfully recovered\n"); + pcie_clear_device_status(edev); acpi_send_edr_status(pdev, edev, EDR_OST_SUCCESS); } else { pci_dbg(edev, "DPC port recovery failed\n");