From: Bjorn Helgaas <helgaas@kernel.org>
To: linux-pci@vger.kernel.org
Cc: Vidya Sagar <vidyas@nvidia.com>
Subject: Re: [Bug 217321] New: Intel platforms can't sleep deeper than PC3 during long idle
Date: Tue, 11 Apr 2023 15:42:29 -0500 [thread overview]
Message-ID: <20230411204229.GA4168208@bhelgaas> (raw)
In-Reply-To: <bug-217321-41252@https.bugzilla.kernel.org/>
On Tue, Apr 11, 2023 at 08:32:04AM +0000, bugzilla-daemon@kernel.org wrote:
> https://bugzilla.kernel.org/show_bug.cgi?id=217321
> ...
> Regression: No
>
> [Symptom]
> Intel cpu can't sleep deeper than pcˇ during long idle
> ~~~
> Pkg%pc2 Pkg%pc3 Pkg%pc6 Pkg%pc7 Pkg%pc8 Pkg%pc9 Pk%pc10
> 15.08 75.02 0.00 0.00 0.00 0.00 0.00
> 15.09 75.02 0.00 0.00 0.00 0.00 0.00
> ^CPkg%pc2 Pkg%pc3 Pkg%pc6 Pkg%pc7 Pkg%pc8 Pkg%pc9 Pk%pc10
> 15.38 68.97 0.00 0.00 0.00 0.00 0.00
> 15.38 68.96 0.00 0.00 0.00 0.00 0.00
> ~~~
> [How to Reproduce]
> 1. run turbostat to monitor
> 2. leave machine idle
> 3. turbostat show cpu only go into pc2~pc3.
>
> [Misc]
> The culprit are this
> a7152be79b62) Revert "PCI/ASPM: Save L1 PM Substates Capability for
> suspend/resume”
>
> if revert a7152be79b62, the issue is gone
Relevant commits:
4ff116d0d5fd ("PCI/ASPM: Save L1 PM Substates Capability for suspend/resume")
a7152be79b62 ("Revert "PCI/ASPM: Save L1 PM Substates Capability for suspend/resume"")
4ff116d0d5fd appeared in v6.1-rc1. Prior to 4ff116d0d5fd, ASPM L1 PM
Substates configuration was not preserved across suspend/resume, so
the system *worked* after resume, but used more power than expected.
But 4ff116d0d5fd caused resume to fail completely on some systems, so
a7152be79b62 reverted it. With a7152be79b62 reverted, ASPM L1 PM
Substates configuration is likely not preserved across suspend/resume.
a7152be79b62 appeared in v6.2-rc8 and was backported to the v6.1
stable series starting with v6.1.12.
KobaKo, you don't mention any suspend/resume in this bug report, but
neither patch should make any difference unless suspend/resume is
involved. Does the platform sleep as expected *before* suspend, but
fail to sleep after resume?
Or maybe some individual device was suspended via runtime power
management, and that device lost its L1 PM Substates config? I don't
know if there's a way to disable runtime PM easily.
The lspci output attached to the bugzilla was not collected as root,
so it lacks the ASPM-related information. Can you do this again with
"sudo lspci -vv"?
next parent reply other threads:[~2023-04-11 20:42 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <bug-217321-41252@https.bugzilla.kernel.org/>
2023-04-11 20:42 ` Bjorn Helgaas [this message]
2023-04-12 12:24 ` [Bug 217321] New: Intel platforms can't sleep deeper than PC3 during long idle Linux regression tracking #adding (Thorsten Leemhuis)
2023-04-12 12:30 ` Thorsten Leemhuis
2023-05-04 15:23 ` Bjorn Helgaas
2023-05-05 6:56 ` Koba Ko
2023-05-22 11:45 ` Linux regression tracking (Thorsten Leemhuis)
2023-05-23 21:49 ` Bjorn Helgaas
2023-05-24 4:15 ` Linux regression tracking #update (Thorsten Leemhuis)
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