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From: Kai-Heng Feng <kai.heng.feng@canonical.com>
Date: Thu, 7 Mar 2024 14:51:05 +0800
Message-ID: <CAAd53p6GEPJe3rNNrUAah5PdLXspKh5Gz9tFstR6SFCREs+9=Q@mail.gmail.com>
Subject: Re: [Regression] [PCI/ASPM] [ASUS PN51] Reboot on resume attempt
 (bisect done; commit found)
To: Michael Schaller <michael@5challer.de>
Cc: Bjorn Helgaas <helgaas@kernel.org>, bhelgaas@google.com, linux-pci@vger.kernel.org, 
	linux-kernel@vger.kernel.org, regressions@lists.linux.dev, macro@orcam.me.uk, 
	ajayagarwal@google.com, sathyanarayanan.kuppuswamy@linux.intel.com, 
	gregkh@linuxfoundation.org, hkallweit1@gmail.com, 
	michael.a.bottini@linux.intel.com, johan+linaro@kernel.org
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Hi Michael,

Sorry for the belated response.

On Wed, Jan 10, 2024 at 8:40=E2=80=AFPM Michael Schaller <michael@5challer.=
de> wrote:
>
>
> On 10.01.24 04:43, Kai-Heng Feng wrote:
> > On Fri, Jan 5, 2024 at 11:51=E2=80=AFPM Bjorn Helgaas <helgaas@kernel.o=
rg> wrote:
> >>
> >> On Fri, Jan 05, 2024 at 12:18:32PM +0100, Michael Schaller wrote:
> >>> On 05.01.24 04:25, Kai-Heng Feng wrote:
> >>>> Just wondering, does `echo 0 > /sys/power/pm_asysnc` help?
> >>>
> >>> Yes, `echo 0 | sudo tee /sys/power/pm_async` does indeed also result =
in a
> >>> working resume. I've tested this on kernel 6.6.9 (which still has com=
mit
> >>> 08d0cc5f3426). I've also attached the relevant dmesg output of the
> >>> suspend/resume cycle in case this helps.
> >>
> >> Thanks for testing that!
> >>
> >>> Furthermore does this mean that commit 08d0cc5f3426 isn't at fault bu=
t
> >>> rather that we are dealing with a timing issue?
> >>
> >> PCI does have a few software timing requirements, mostly related to
> >> reset and power state (D0/D3cold).  ASPM has some timing parameters,
> >> too, but I think they're all requirements on the hardware, not on
> >> software.
> >>
> >> Adding an arbitrary delay anywhere shouldn't break anything, and other
> >> than those few required situations, it shouldn't fix anything either.
> >
> > At least it means 8d0cc5f3426 isn't the culprit?
> >
> > Michael, does the issue happen when iwlwifi module is not loaded? It
> > can be related to iwlwifi firmware.
> >
> > Kai-Heng
> >
> The issue still happens if the iwlwifi module has been blacklisted and
> after a reboot. This was again with vanilla kernel 6.6.9 and I've
> confirmed via dmesg that iwlwifi wasn't loaded.

Can you please give latest mainline kernel a try? With commit
f93e71aea6c60ebff8adbd8941e678302d377869 (Revert "PCI/ASPM: Remove
pcie_aspm_pm_state_change()") reverted.

Also do you have efi-pstore enabled? Is there anything logged in
/var/lib/systemd/pstore (assuming systemd is used)?

Kai-Heng

>
> I've also checked if there is a newer firmware but Ubuntu 23.10 is
> already using the newest firmware available from
> https://git.kernel.org/pub/scm/linux/kernel/git/firmware/linux-firmware.g=
it/log/iwlwifi-8265-36.ucode
> (version 36.ca7b901d.0 according to dmesg).
>
> Michael
>
> >>
> >> Bjorn