Re: [PATCH] acpi: pcihp: make pending delete expire in 5sec

[Gerd Hoffmann]

  Hi,

> > Allowing pending delete expire brings ACPI PCI hotplug on par
> > with native PCIe unplug behavior [1] which in its turn refers
> > back to ACPI PCI hotplug ability to repeat unplug requests.

> A bit concerned about how this interacts with failover,
> and 5sec is a lot of time that I hoped we'd avoid with acpi.
> Any better ideas of catching such misbehaving guests?

The 5sec are coming from the pcie spec: The hot-unplug request can be
canceled within 5 seconds by pressing the button again. The problem here
is that both hotplug and hot-unplug use the same signaling path, so we
really have to wait the 5 seconds to avoid the OS mis-interpreting the
button press as 'cancel' event.

ACPI hotplug hasn't this problem.  A unplug request is a unplug request,
period.  And it can't be canceled.  So it should be possible to use a
shorter period.  Possibly even no delay at all.

take care,
  Gerd