linux-kernel - Re: [PATCH V1] PCI/ASPM: Save/restore L1SS Capability for suspend/resume

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Message-ID: <1b37e4cd-79d-7031-ea64-f72f1acdec3d@panix.com>
Date:   Sat, 5 Feb 2022 09:32:00 -0800 (PST)
From:   "Kenneth R. Crudup" <kenny@...ix.com>
To:     Vidya Sagar <vidyas@...dia.com>
cc:     Bjorn Helgaas <helgaas@...nel.org>, bhelgaas@...gle.com,
        lorenzo.pieralisi@....com, hkallweit1@...il.com,
        wangxiongfeng2@...wei.com, mika.westerberg@...ux.intel.com,
        kai.heng.feng@...onical.com, chris.packham@...iedtelesis.co.nz,
        yangyicong@...ilicon.com, treding@...dia.com, jonathanh@...dia.com,
        abhsahu@...dia.com, sagupta@...dia.com, linux-pci@...r.kernel.org,
        linux-kernel@...r.kernel.org, kthota@...dia.com,
        mmaddireddy@...dia.com, sagar.tv@...il.com,
        "Kenneth R. Crudup" <kenny@...ix.com>
Subject: Re: [PATCH V1] PCI/ASPM: Save/restore L1SS Capability for
 suspend/resume


On Sat, 5 Feb 2022, Kenneth R. Crudup wrote:

> > If you'd like, I could try re-applying the previous problem commit or your
> > attempted fix on top of Linus' master if you'd like to see if something was
> > fixed somewhere else in the PCIe subsystem, but if you think it's not worth-
> > while I'm satisfied with the current fix (or probably more-exactly for my
> > particular machine, lack of regression).

On Sat, 5 Feb 2022, Vidya Sagar wrote:

> That would be a good starting point to understand it better. In fact if the
> previous problematic patch works fine on master, then, we are sure that
> something in the sub-system would have fixed the issue.

So this is my report of the regression I'd found with Bjorn's original commit:
----
Date: Fri, 25 Dec 2020 16:38:56
From: Kenneth R. Crudup <kenny@...ix.com>
To: vidyas@...dia.com
Cc: bhelgaas@...gle.com
Subject: Commit 4257f7e0 ("PCI/ASPM: Save/restore L1SS Capability for suspend/resume") causing hibernate resume
    failures

I've been running Linus' master branch on my laptop (Dell XPS 13 2-in-1). With
this commit in place, after resuming from hibernate my machine is essentially
useless, with a torrent of disk I/O errors on my NVMe device (at least, and
possibly other devices affected) until a reboot.

I do use tlp to set the PCIe ASPM to "performance" on AC and "powersupersave"
on battery.

Let me know if you need more information.
----

I just reapplied it on top of Linus' master and not only did it go in cleanly(!),
NOW I'm not getting any issues after a suspend/resume. I've attached the output
of "lspci -vvvvnn" before a hibernation (but not the very *first* one; if you
need that output, let me know) and will submit the same post-hibernation (which
is the same as the pre-hibernation case) and the post-suspend case (which is
slightly different) in subsequent E-mails (due to attachment size).

	-Kenny

-- 
Kenneth R. Crudup / Sr. SW Engineer, Scott County Consulting, Orange County CA
View attachment "lspci-bjorn-4257f7e008-before-hibernate" of type "text/plain" (42582 bytes)