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Date: Tue, 4 Nov 2008 02:38:37 +0000
From: Matthew Garrett <mjg59@srcf.ucam.org>
To: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>
Cc: linux-pci@vger.kernel.org, kristen.c.accardi@intel.com,
       linux-kernel@vger.kernel.org
Subject: Re: [PATCH] Add option to passively listen for PCIE hotplug events
Message-ID: <20081104023837.GA12165@srcf.ucam.org>
References: <20081029200903.GA1678@srcf.ucam.org> <490FAC33.9050808@jp.fujitsu.com> <20081104020700.GA11761@srcf.ucam.org> <490FB397.8050809@jp.fujitsu.com>
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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!
-- 
Matthew Garrett | mjg59@srcf.ucam.org
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