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Date:   Wed, 10 Jun 2020 12:52:17 +0300
From:   Mika Westerberg <mika.westerberg@linux.intel.com>
To:     Paul Menzel <pmenzel@molgen.mpg.de>
Cc:     Bjorn Helgaas <bhelgaas@google.com>, linux-pci@vger.kernel.org,
        LKML <linux-kernel@vger.kernel.org>,
        Mario Limonciello <mario.limonciello@dell.com>,
        it+linux-pci@molgen.mpg.de, amd-gfx@lists.freedesktop.org
Subject: Re: close() on some Intel CNP-LP PCI devices takes up to 2.7 s
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On Wed, Jun 10, 2020 at 08:18:07AM +0200, Paul Menzel wrote:
> Thank you for replying so quickly. Hopefully, I’ll be able to test the
> commit tomorrow.
> 
> One question though. The commit talks about resuming from suspend. I
> understand that training happens there.
> 
> In my case the system is already running. So I wonder, why link(?) training
> would still happening.

It also includes runtime PM so when the PCIe topology goes into D3cold
the links are "down" so once you run tool such as lspci the links need
to be re-trained to be able to access the devices connected to them.