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Subject: Re: Should a PCIe Link Down event set the PCI_DEV_DISCONNECTED bit?
To: Alex_Gagniuc@Dellteam.com, lukas@wunner.de
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From: Sinan Kaya <okaya@kernel.org>
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Date: Fri, 27 Jul 2018 11:17:49 -0700
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On 7/27/2018 10:51 AM, Alex_Gagniuc@Dellteam.com wrote:
>> The first problem with that patch was that I hadn't fully understood
>> yet when to set PCI_DEV_DISCONNECTED and when not to set it.
> I think PCI_DEV_DISCONNECTED is a documentation issue above all else.
> The history I was given is that drivers would take a very long time to
> tear down a device. Config space IO to an nonexistent device took a long
> while to time out. Performance was one motivation -- and was not documented.
> 

Completion timeouts are typically in the orders of 50ms. If you have a
lot of outstanding non-posted requests, it will take time for SW to
flush all requests.