On Wed, Mar 15, 2023 at 04:54:49PM -0700, Kuppuswamy Sathyanarayanan wrote:
> Commit 068c29a248b6 ("PCI/ERR: Clear PCIe Device Status errors only if
> OS owns AER") adds support to clear error status in the Device Status
> Register(DEVSTA) only if OS owns the AER support. But this change
> breaks the requirement of the EDR feature which requires OS to cleanup
> the error registers even if firmware owns the control of AER support.
>
> More details about this requirement can be found in PCIe Firmware
> specification v3.3, Table 4-6 Interpretation of the _OSC Control Field.
> If the OS supports the Error Disconnect Recover (EDR) feature and
> firmware sends the EDR event, then during the EDR recovery window, OS
> is responsible for the device error recovery and holds the ownership of
> the following error registers.
>
> • Device Status Register
> • Uncorrectable Error Status Register
> • Correctable Error Status Register
> • Root Error Status Register
> • RP PIO Status Register
>
> So call pcie_clear_device_status() in edr_handle_event() if the error
> recovery is successful.
>
> Reported-by: Tsaur Erwin <erwin.tsaur@xxxxxxxxx>
> Signed-off-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@xxxxxxxxxxxxxxx>
> ---
>
> Changes since v1:
> * Rebased on top of v6.3-rc1.
> * Fixed a typo in pcie_clear_device_status().
>
> 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 a6b9b479b97a..87734e4c3c20 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);
The implementation note in PCI Firmware r3.3, sec 4.6.12, shows the OS
clearing error status *after* _OST is evaluated.
On the other hand, the _OSC DPC control bit in table 4-6 says that if
the OS does not have DPC control, it can only write the Device Status
error bits between the EDR Notify and invoking _OST.
Is one of those wrong, or am I missing something?
Bjorn
