Re: [PATCH] pci: fix broadcom secondary bus reset handling

[Lukas Wunner <lukas@wunner.de>]

On Wed, May 01, 2024 at 07:51:18AM -0700, Keith Busch wrote:
> After a link reset, the Broadcom / LSI PEX890xx PCIe Gen 5 Switch in synth
> mode will temporarily insert a fake place-holder device, 1000 02b2, before
> the link is actually active for the expected downstream device. Confirm
> the device's identifier matches what we expect before moving forward.
> Otherwise, the pciehp driver may unmask hotplug notifications before
> the link is actually active, which triggers an undesired device removal.

This won't work if the device was hot-swapped with a different one
and thus correctly returns a different Vendor/Device ID.  We'd wait
for the device to report the previous device's Vendor/Device ID,
which doesn't make sense.

It would be possible to raise d3cold_delay in struct pci_dev for
children of affected Broadcom switches.  Have you considered that
as a potential solution?

Thanks,

Lukas