linux-kernel - Re: [REGRESSION] probe with driver acpi-fan failed with error -22

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Date: Tue, 4 Jun 2024 14:07:22 +0200
From: "Rafael J. Wysocki" <rafael@...nel.org>
To: Laura Nao <laura.nao@...labora.com>
Cc: kernel@...labora.com, lenb@...nel.org, linux-acpi@...r.kernel.org, 
	linux-kernel@...r.kernel.org, rafael@...nel.org, regressions@...ts.linux.dev
Subject: Re: [REGRESSION] probe with driver acpi-fan failed with error -22

On Mon, Jun 3, 2024 at 8:20 PM Rafael J. Wysocki <rafael@...nel.org> wrote:
>
> Hi,
>
> On Fri, May 31, 2024 at 1:35 PM Laura Nao <laura.nao@...labora.com> wrote:
> >
> > Hello,
> >
> > On 5/30/24 17:37, Laura Nao wrote:
> > > Hello,
> > >
> > > We have identified a regression in the acpi-fan driver probe between
> > > v6.9-rc7 and v6.10-rc1 on some Intel Chromebooks in the Collabora LAVA
> > > lab.
> > >
> > > For the Acer Chromebook Spin 514 (CP514-2H), the following error is
> > > reported in the logs:
> > >
> > > [    0.651202] acpi-fan INTC1044:00: probe with driver acpi-fan failed with error -22
> > >
> > > Similar errors are reported on other devices with fans compatible with
> > > the same driver.
> > >
> > > On Acer Chromebox CXI4, ASUS Chromebook Flip C436FA and
> > > HP Chromebook x360 14 G1:
> > >
> > > [    0.488001] acpi-fan INT3404:00: probe with driver acpi-fan failed with error -22
> > >
> > > On ASUS Chromebook Vero 514 CBV514-1H:
> > >
> > > [    1.168905] acpi-fan INTC1048:00: probe with driver acpi-fan failed with error -22
> > >
> > > The issue is still present on next-20240529.
> > >
> > > I'm sending this report to track the regression while a fix is
> > > identified. I'll investigate the issue/run a bisection and report back
> > > with the results.
> > >
> > > This regression was discovered during some preliminary tests with the
> > > ACPI probe kselftest [1] in KernelCI. The config used was the upstream
> > > x86_64 defconfig with a fragment applied on top [2].
> > >
> > > Best,
> > >
> > > Laura
> > >
> > > [1] https://lore.kernel.org/all/20240308144933.337107-1-laura.nao@collabora.com/
> > > [2] https://pastebin.com/raw/0tFM0Zyg
> > >
> > > #regzbot introduced: v6.9-rc7..v6.10-rc1
> >
> > The issue started happening after:
> > https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/drivers/thermal/thermal_core.c?h=v6.10-rc1&id=31a0fa0019b022024cc082ae292951a596b06f8c
> >
> > Before this commit, get_cur_state() was not called by
> > __thermal_cooling_device_register, so the error was not triggered.
> >
> > After enabling debugging for the acpi-fan driver, I noticed these errors
> > in the logs:
> >
> > [    0.682224] acpi INTC1044:00: Invalid control value returned
> > [    0.682635] acpi INTC1044:00: Invalid control value returned
> >
> > The value stored in fst.control is 255, which is indeed not a valid
> > value.
> >
> > I suspect this might be a firmware issue that is now manifesting due to
> > the addition of the extra get_cur_state() call.
> >
> > I'll dig a bit more and report back.
>
> It looks like _FST returns all ones if it is evaluated before _FSL on
> the affected platforms.
>
> It shouldn't do that, but then it is not particularly useful to fail
> cdev registration for this reason.
>
> The attached patch should work around this issue, please try it and report back.

A !ret check is missing in that patch, so please try the attached new
version of it instead.

Thanks!

Download attachment "thermal-cdev-init-2.patch" of type "application/x-patch" (2097 bytes)