Re: [PATCH pci-next] pci/edr: Ignore Surprise Down error on hot removal

[Smita Koralahalli]

Hi Ethan,

On 3/4/2024 3:58 AM, Lukas Wunner wrote:
> On Mon, Mar 04, 2024 at 04:08:19AM -0500, Ethan Zhao wrote:
> > Per PCI firmware spec r3.3 sec 4.6.12, for firmware first mode DPC
> > handling path, FW should clear UC errors logged by port and bring link
> > out of DPC, but because of ambiguity of wording in the spec, some BIOSes
> > doesn't clear the surprise down error and the error bits in pci status,
> > still notify OS to handle it. thus following trick is needed in EDR when
> > double reporting (hot removal interrupt && dpc notification) is hit.

Please correct me if I'm wrong.

When there is double reporting (hot removal interrupt && dpc 
notification), won't the DPC handler be called always which takes care 
of clearing the surprise down errors? Do we need it again from EDR handler?

Thanks
Smita

> Please provide more detailed information about the hardware and BIOS
> affected by this.
>
>
> > -static void dpc_handle_surprise_removal(struct pci_dev *pdev)
> > +bool  dpc_handle_surprise_removal(struct pci_dev *pdev)
> >   {
> > +	if (!dpc_is_surprise_removal(pdev))
> > +		return false;
>
> This change of moving dpc_is_surprise_removal() into
> dpc_handle_surprise_removal() seems unrelated to the problem at hand.
>
> Please drop it if it's unnecessary to fix the issue.
>
>
> > --- a/drivers/pci/pcie/edr.c
> > +++ b/drivers/pci/pcie/edr.c
> > @@ -184,6 +184,9 @@ static void edr_handle_event(acpi_handle handle, u32 event, void *data)
> >   		goto send_ost;
> >   	}
> >   
> > +	if (dpc_handle_surprise_removal(edev))
> > +		goto send_ost;
> > +
> >   	dpc_process_error(edev);
> >   	pci_aer_raw_clear_status(edev);
>
> This seems to be the only necessary change.  Please reduce the
> patch to contain only it and no other refactoring.
>
> Please capitalize the "PCI/EDR: " prefix in the subject and add
> a Fixes tag.
>
> Thanks,
>
> Lukas