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From: Laura Nao <laura.nao@collabora.com>
To: laura.nao@collabora.com
Cc: kernel@collabora.com,
	lenb@kernel.org,
	linux-acpi@vger.kernel.org,
	linux-kernel@vger.kernel.org,
	rafael@kernel.org,
	regressions@lists.linux.dev
Subject: Re: [REGRESSION] probe with driver acpi-fan failed with error -22
Date: Fri, 31 May 2024 13:35:34 +0200
Message-Id: <20240531113534.577055-1-laura.nao@collabora.com>
In-Reply-To: <20240530153727.843378-1-laura.nao@collabora.com>
References: <20240530153727.843378-1-laura.nao@collabora.com>
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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.

Best,

Laura

#regzbot introduced: 31a0fa0019