Re: reset_slot() callback not respecting MPS config

[Lukas Wunner <lukas@wunner.de>]

On Fri, May 23, 2025 at 09:02:38AM +0200, Niklas Cassel wrote:
> I kind of liked the earlier revision of Mani's series where we kicked the
> devices off the bus, that way, we would re-use the exact same code paths
> as when doing the initial enumeration.
> 
> Also, by removing the device, the exact same solution works fine both for
> link-down (since the device might never come back again), and for a sysfs
> initiated reset.

PCI drivers such as NVMe are capable of recovering gracefully from reset.
That's a very important feature for data center use cases.

The PCIe hotplug driver goes to great lengths to avoid de-enumeration
and re-enumeration and instead allow for recovery from reset (see e.g.
the invocation of pci_dpc_recovered() and pciehp_ignore_dpc_link_change()
in pciehp_ist()).

So no, we do not want to remove devices in response to reset if we can
help it.  We generally only de-enumerate and re-enumerate devices on
hotplug or if explicitly told to do so via sysfs "remove" / "rescan"
attributes.

Thanks,

Lukas