Re: [PATCH v3 1/4] PCI: Keep AER status in pci_restore_state()

[Kai-Heng Feng]

Hi Sathyanarayanan,

On Thu, Apr 20, 2023 at 10:39 PM Sathyanarayanan Kuppuswamy
<sathyanarayanan.kuppuswamy@xxxxxxxxxxxxxxx> wrote:
>
> Hi Kai,

It's Kai-Heng :)

>
> On 4/20/23 5:59 AM, Kai-Heng Feng wrote:
> > When AER is using the same IRQ as PME, AER interrupt is treated as a
> > wakeup event and it can disrupt system suspend process.
> >
> > If that happens, the system will report it's woken up by PME IRQ without
> > indicating any AER error since AER status is cleared on resume.
> >
> > So keep the AER status so users can know the system is woken up by AER
> > instead of PME.
> >
> > Reviewed-by: Mika Westerberg <mika.westerberg@xxxxxxxxxxxxxxx>
> > Signed-off-by: Kai-Heng Feng <kai.heng.feng@xxxxxxxxxxxxx>
> > ---
>
> Any history on why it is cleared before? Is it done to hide some resume
> issues?

It was introduced by commit b07461a8e45b ("PCI/AER: Clear error status
registers during enumeration and restore").
The justification is quite reasonable so I think maybe we should keep it as is.

Kai-Heng

>
> > v3:
> >  - No change.
> >
> > v2:
> >  - New patch.
> >
> >  drivers/pci/pci.c | 1 -
> >  1 file changed, 1 deletion(-)
> >
> > diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
> > index 7a67611dc5f4..71aead00fc20 100644
> > --- a/drivers/pci/pci.c
> > +++ b/drivers/pci/pci.c
> > @@ -1778,7 +1778,6 @@ void pci_restore_state(struct pci_dev *dev)
> >       pci_restore_dpc_state(dev);
> >       pci_restore_ptm_state(dev);
> >
> > -     pci_aer_clear_status(dev);
> >       pci_restore_aer_state(dev);
> >
> >       pci_restore_config_space(dev);
>
> --
> Sathyanarayanan Kuppuswamy
> Linux Kernel Developer