On Thu, Apr 18, 2024 at 9:15 AM Kuppuswamy Sathyanarayanan
<sathyanarayanan.kuppuswamy@xxxxxxxxxxxxxxx> wrote:
>
>
> On 4/15/24 9:32 PM, Kai-Heng Feng wrote:
> > In addition to nearest upstream bridge, driver may want to know if the
> > entire hierarchy can be powered off to perform different action.
> >
> > So walk higher up the hierarchy to find out if any device has valid
> > _PR3.
> >
> > The user will be introduced in next patch.
> >
> > Signed-off-by: Kai-Heng Feng <kai.heng.feng@xxxxxxxxxxxxx>
> > ---
>
> Since it has been a while, I was not sure what this series is about.
>
> IMO, it is better to include a cover letter with the summary of your
> changes.
OK, will do in next revision.
>
>
> > v8:
> > - No change.
> >
> > drivers/pci/pci.c | 16 ++++++++++++++++
> > include/linux/pci.h | 2 ++
> > 2 files changed, 18 insertions(+)
> >
> > diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
> > index e5f243dd4288..7a5662f116b8 100644
> > --- a/drivers/pci/pci.c
> > +++ b/drivers/pci/pci.c
> > @@ -6225,6 +6225,22 @@ bool pci_pr3_present(struct pci_dev *pdev)
> > acpi_has_method(adev->handle, "_PR3");
> > }
> > EXPORT_SYMBOL_GPL(pci_pr3_present);
> > +
> > +bool pci_ancestor_pr3_present(struct pci_dev *pdev)
> > +{
> > + struct pci_dev *parent = pdev;
> > +
> > + if (acpi_disabled)
> > + return false;
> > +
> > + while ((parent = pci_upstream_bridge(parent))) {
> > + if (pci_pr3_present(pdev))
>
> I think it should be "parent" here?
Thanks for catching this.
But this patch will be dropped in next version for better simplicity.
Kai-Heng
>
> > + return true;
> > + }
> > +
> > + return false;
> > +}
> > +EXPORT_SYMBOL_GPL(pci_ancestor_pr3_present);
> > #endif
> >
> > /**
> > diff --git a/include/linux/pci.h b/include/linux/pci.h
> > index 16493426a04f..cd71ebfd0f89 100644
> > --- a/include/linux/pci.h
> > +++ b/include/linux/pci.h
> > @@ -2620,10 +2620,12 @@ struct irq_domain *pci_host_bridge_acpi_msi_domain(struct pci_bus *bus);
> > void
> > pci_msi_register_fwnode_provider(struct fwnode_handle *(*fn)(struct device *));
> > bool pci_pr3_present(struct pci_dev *pdev);
> > +bool pci_ancestor_pr3_present(struct pci_dev *pdev);
> > #else
> > static inline struct irq_domain *
> > pci_host_bridge_acpi_msi_domain(struct pci_bus *bus) { return NULL; }
> > static inline bool pci_pr3_present(struct pci_dev *pdev) { return false; }
> > +static inline bool pci_ancestor_pr3_present(struct pci_dev *pdev) { return false; }
> > #endif
> >
> > #ifdef CONFIG_EEH
>
> --
> Sathyanarayanan Kuppuswamy
> Linux Kernel Developer
>
