Re: [PATCH] Add option to passively listen for PCIE hotplug events

Matthew Garrett
2008-11-04T02:38:51Z

On Tue, Nov 04, 2008 at 11:29:43AM +0900, Kenji Kaneshige wrote:
> Matthew Garrett wrote:
> >What do you mean by "not work properly"? The hardware we've tested with
> >fires events even without an OSHP method being present. That's the case
> >we're trying to deal with.
> >
>
> Because the explanation of PCI Express Native Hot Plug control bit in
> _OSC return value in PCI firmware spec says
>
> "... If firmware allows the operating system control of this feature,
> then in the context of the _OSC method, it must ensure that all hot
> plug events are routed to device interrupts as described in the PCI
> Express Base Specification. ..."
>
> My understanding is that it is not ensured that all hot plug events
> are routed to device interrupts, if hotplug control is not granted.

My understanding is that in the worst case the hardware/firmware won't
give us any events - that's basically equivalent to not having the
driver loaded at all. On hardware that gives us the events anyway, we
get some extra functionality.

Thanks for the feedback!