On Fri, Apr 04, 2025 at 06:42:32AM +0200, Lukas Wunner wrote:
> On Thu, Apr 03, 2025 at 11:18:09PM -0500, Shawn Anastasio wrote:
> > The Microsemi Switchtec PM8533 PFX 48xG3 [11f8:8533] PCIe switch system
> > was observed to incorrectly assert the Presence Detect Set bit in its
> > capabilities when tested on a Raptor Computing Systems Blackbird system,
> > resulting in the hot insert path never attempting a rescan of the bus
> > and any downstream devices not being re-detected.
> >
> > Work around this by additionally checking whether the PCIe data link is
> > active or not when performing presence detection on downstream switches'
> > ports, similar to the pciehp_hpc.c driver.
> [...]
> > --- a/drivers/pci/hotplug/pnv_php.c
> > +++ b/drivers/pci/hotplug/pnv_php.c
> > @@ -390,6 +390,20 @@ static int pnv_php_get_power_state(struct hotplug_slot
> > *slot, u8 *state)
> > return 0;
> > }
> >
> > +static int pcie_check_link_active(struct pci_dev *pdev)
> > +{
> > + u16 lnk_status;
> > + int ret;
> > +
> > + ret = pcie_capability_read_word(pdev, PCI_EXP_LNKSTA, &lnk_status);
> > + if (ret == PCIBIOS_DEVICE_NOT_FOUND || PCI_POSSIBLE_ERROR(lnk_status))
> > + return -ENODEV;
> > +
> > + ret = !!(lnk_status & PCI_EXP_LNKSTA_DLLLA);
> > +
> > + return ret;
> > +}
> > +
>
> This appears to be a 1:1 copy of pciehp_check_link_active(),
> save for the ctrl_dbg() call.
>
> For the sake of code-reuse, please move the function into the
> PCI library drivers/pci/pci.c so that it can be used everywhere.
>
> Note that there's another patch pending which does exactly that:
>
> https://lore.kernel.org/r/20250225-qps615_v4_1-v4-7-e08633a7b...@oss.qualcomm.com/
>
> So either include that patch in your series (addressing the review
> feedback I sent for it and cc'ing the original submitter) or wait
> for it to be respun by the original submitter.
Update -- Krishna respun the patch:
https://lore.kernel.org/r/20250412-qps615_v4_1-v5-7-5b6a06132...@oss.qualcomm.com/
