pcie_clear_device_status() resets the error bits in the PCIe Device Status
Register (PCI_EXP_DEVSTA).
Previously we did this unconditionally, but on ACPI systems, the _OSC AER
bit negotiates control of the AER capability. Per sec 4.5.1 of the System
Firmware Intermediary _OSC and DPC Updates ECN [1], this bit also covers
other error enable/status bits including the following:
Correctable Error Reporting Enable
Non-Fatal Error Reporting Enable
Fatal Error Reporting Enable
Unsupported Request Reporting Enable
These bits are all in the PCIe Device Control register (the ECN omitted
"Reporting", but I think that's a typo), so by implication the _OSC AER bit
also applies to the error status bits in the PCIe Device Status register:
Correctable Error Detected
Non-Fatal Error Detected
Fatal Error Detected
Unsupported Request Detected
Clear the PCIe Device Status error bits only when the OS controls the AER
capability and related error enable/status bits. If platform firmware
controls the AER capability, firmware is responsible for clearing these
bits.
One call path leading here is:
ghes_do_proc
ghes_handle_aer
aer_recover_queue
schedule_work(&aer_recover_work)
...
aer_recover_work_func
pcie_do_recovery
pcie_clear_device_status
[1] System Firmware Intermediary (SFI) _OSC and DPC Updates ECN, Feb 24,
2020, affecting PCI Firmware Specification, Rev. 3.2
https://members.pcisig.com/wg/PCI-SIG/document/14076
[bhelgaas: commit log, move test from pcie_clear_device_status() to callers]
Link: https://lore.kernel.org/r/20200622113523.891666-1-Jonathan.Cameron@huawei.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
if (aer)
pci_write_config_dword(dev, aer + PCI_ERR_COR_STATUS,
info->status);
- pcie_clear_device_status(dev);
+ if (pcie_aer_is_native(dev))
+ pcie_clear_device_status(dev);
} else if (info->severity == AER_NONFATAL)
pcie_do_recovery(dev, pci_channel_io_normal, aer_root_reset);
else if (info->severity == AER_FATAL)
pci_dbg(dev, "broadcast resume message\n");
pci_walk_bus(bus, report_resume, &status);
- pcie_clear_device_status(dev);
+ if (pcie_aer_is_native(dev))
+ pcie_clear_device_status(dev);
pci_aer_clear_nonfatal_status(dev);
pci_info(dev, "device recovery successful\n");
return status;