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

[Gerd Hoffmann]

On Tue, Apr 04, 2023 at 10:30:55AM +0200, Igor Mammedov wrote:
> On Tue, 4 Apr 2023 09:03:59 +0200
> Gerd Hoffmann <kraxel@redhat.com> wrote:
> 
> >   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.
> 
> Any pointer to spec?

pcie base spec, section 6.7.1.5. Attention Button

> Does it apply to SHPC too?

Yes (section 2.2.5. Attention Button).

take care,
  Gerd