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

[Igor Mammedov <imammedo@redhat.com>]

On Tue, 4 Apr 2023 12:46:45 +0200
Gerd Hoffmann <kraxel@redhat.com> wrote:

> 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).

shouldn't we set pending_deleted_expires_ms to 5sec for SHPC
as we do with PCIe?

> 
> take care,
>   Gerd
>