ACK: [PATCH 1/1][SRU][Jammy] UBUNTU: SAUCE: vmd: fixup bridge ASPM by driver name instead

[You-Sheng Yang]

On Tue, Apr 26, 2022 at 3:21 PM Kleber Souza <kleber.souza at canonical.com> wrote:
>
> On 11.04.22 11:24, You-Sheng Yang wrote:
> > BugLink: https://bugs.launchpad.net/bugs/1942160
> >
> > Additional VMD bridge IDs needed for new Alder Lake platforms, but
> > actually there is no a complete list for them. Here we match bridge
> > devices if they're directly attached to a VMD controller instead.
> >
> > Signed-off-by: You-Sheng Yang <vicamo.yang at canonical.com>
>
> This is changing some code added by us as SAUCE, so I guess not really
> upstream material.

Yes, this is our hack before Intel ever comes out a fix that addresses
the same problem. There is one changeset
https://lore.kernel.org/linux-pci/b3caabef-f91e-ff4d-dfe2-8aa0869fadb6@linux.dev/
proposed by Intel recently, but we've verified that is not sufficient
for us to obsolete this hack yet. We'll see if it's getting mature in
v5.18 or maybe v5.19.

> Acked-by: Kleber Sacilotto de Souza <kleber.souza at canonical.com>
>
> Thanks
>
> > ---
> >   drivers/pci/quirks.c | 32 +++++++++++++++++++++++---------
> >   1 file changed, 23 insertions(+), 9 deletions(-)
> >
> > diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c
> > index bf3af7d81bdc2..73e346d990b16 100644
> > --- a/drivers/pci/quirks.c
> > +++ b/drivers/pci/quirks.c
> > @@ -5820,23 +5820,36 @@ DECLARE_PCI_FIXUP_CLASS_HEADER(0x1ac1, 0x089a,
> >                              PCI_CLASS_NOT_DEFINED, 8, apex_pci_fixup_class);
> >
> >   /*
> > - * Device [8086:9a09], [8086:a0b0] and [8086:a0bc]
> >    * BIOS may not be able to access config space of devices under VMD domain, so
> >    * it relies on software to enable ASPM for links under VMD.
> >    */
> > -static const struct pci_device_id vmd_bridge_tbl[] = {
> > -     { PCI_VDEVICE(INTEL, 0x9a09) },
> > -     { PCI_VDEVICE(INTEL, 0xa0b0) },
> > -     { PCI_VDEVICE(INTEL, 0xa0bc) },
> > -     { }
> > -};
> > +static bool pci_fixup_is_vmd_bridge(struct pci_dev *pdev)
> > +{
> > +     struct pci_bus *bus = pdev->bus;
> > +     struct device *dev;
> > +     struct pci_driver *pdrv;
> > +
> > +     if (!pci_is_root_bus(bus))
> > +             return false;
> > +
> > +     dev = bus->bridge->parent;
> > +     if (dev == NULL)
> > +             return false;
> > +
> > +     pdrv = pci_dev_driver(to_pci_dev(dev));
> > +     if (pdrv == NULL || strcmp("vmd", pdrv->name))
> > +             return false;
> > +
> > +     return true;
> > +}
> >
> >   static void pci_fixup_enable_aspm(struct pci_dev *pdev)
> >   {
> > -     if (!pci_match_id(vmd_bridge_tbl, pdev))
> > +     if (!pci_fixup_is_vmd_bridge(pdev))
> >               return;
> >
> >       pdev->dev_flags |= PCI_DEV_FLAGS_ENABLE_ASPM;
> > +     pci_info(pdev, "enable ASPM for pci bridge behind vmd");
> >   }
> >   DECLARE_PCI_FIXUP_CLASS_HEADER(PCI_VENDOR_ID_INTEL, PCI_ANY_ID,
> >                              PCI_CLASS_BRIDGE_PCI, 8, pci_fixup_enable_aspm);
> > @@ -5851,7 +5864,7 @@ static void pci_fixup_enable_vmd_nvme_ltr(struct pci_dev *pdev)
> >       if (!parent)
> >               return;
> >
> > -     if (!pci_match_id(vmd_bridge_tbl, parent))
> > +     if (!pci_fixup_is_vmd_bridge(parent))
> >               return;
> >
> >       pos = pci_find_ext_capability(pdev, PCI_EXT_CAP_ID_LTR);
> > @@ -5869,6 +5882,7 @@ static void pci_fixup_enable_vmd_nvme_ltr(struct pci_dev *pdev)
> >       /* 3145728ns, i.e. 0x300000ns */
> >       pci_write_config_word(pdev, pos + PCI_LTR_MAX_SNOOP_LAT, 0x1003);
> >       pci_write_config_word(pdev, pos + PCI_LTR_MAX_NOSNOOP_LAT, 0x1003);
> > +     pci_info(pdev, "enable LTR for nvme behind vmd");
> >   }
> >   DECLARE_PCI_FIXUP_CLASS_EARLY(PCI_ANY_ID, PCI_ANY_ID,
> >                             PCI_CLASS_STORAGE_EXPRESS, 0, pci_fixup_enable_vmd_nvme_ltr);
>


-- 
Regards,
You-Sheng Yang