linux-kernel - Re: [PATCH v2 0/6] platform/x86: lenovo-wmi-{capdata,other}: Add HWMON for fan speed

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Message-ID: <CAFqHKTk7n+aiEgRtGHNZn9gb00rviH7GhVPdh2Cwb4vTQK8Zwg@mail.gmail.com>
Date: Thu, 30 Oct 2025 19:01:46 -0700
From: Derek John Clark <derekjohn.clark@...il.com>
To: Rong Zhang <i@...g.moe>
Cc: Mark Pearson <mpearson-lenovo@...ebb.ca>, Armin Wolf <W_Armin@....de>, 
	Hans de Goede <hansg@...nel.org>, Ilpo Järvinen <ilpo.jarvinen@...ux.intel.com>, 
	Guenter Roeck <linux@...ck-us.net>, platform-driver-x86@...r.kernel.org, 
	linux-kernel@...r.kernel.org, linux-hwmon@...r.kernel.org
Subject: Re: [PATCH v2 0/6] platform/x86: lenovo-wmi-{capdata,other}: Add
 HWMON for fan speed

On Thu, Oct 30, 2025 at 12:40 PM Rong Zhang <i@...g.moe> wrote:
>
> Lenovo WMI Other Mode interface also supports querying or setting fan
> speed RPM. This capability is decribed by LENOVO_CAPABILITY_DATA_00.
> Besides, LENOVO_FAN_TEST_DATA provides reference data for self-test of
> cooling fans, including minimum and maximum fan speed RPM.
>
> This patchset turns lenovo-wmi-capdata01 into a unified driver (now
> named lenovo-wmi-capdata) for LENOVO_CAPABILITY_DATA_{00,01} and
> LENOVO_FAN_TEST_DATA; then adds HWMON support for lenovo-wmi-other:
>
>  - fanX_enable: enable/disable the fan (tunable)
>  - fanX_input: current RPM
>  - fanX_max: maximum RPM
>  - fanX_min: minimum RPM
>  - fanX_target: target RPM (tunable)
>
> This implementation doesn't require all capability data to be available,
> and is capable to expose interfaces accordingly:
>
>  - Having LENOVO_CAPABILITY_DATA_00: exposes fanX_{enable,input,target}
>  - Having LENOVO_CAPABILITY_DATA_01: exposes firmware_attributes
>  - Having LENOVO_FAN_TEST_DATA: exposes fanX_{max,min}
>
> Changes in v2:
> - Add a workaround for ACPI methods that return a 4B buffer for u32
>   (thanks Armin Wolf)
> - Fix function documentation (thanks kernel test bot)
> - Reword documentation (thanks Derek J. Clark)
> - Squash min/max reporting patch into the initial HWMON one (ditto)
> - Query 0x04050000 for interface availability (ditto)
>   - New parameter "expose_all_fans" to skip this check
> - Enforce min/max RPM constraint on set (ditto)
>   - New parameter "relax_fan_constraint" to disable this behavior
>   - Drop parameter "ignore_fan_cap", superseded by the next one
>   - New parameter "expose_all_fans" to expose fans w/o such data
> - Assume auto mode on probe (ditto)
> - Do not register HWMON device if no fan can be exposed
> - fanX_target: Return -EBUSY instead of raw target value when fan stops
> - Link to v1: https://lore.kernel.org/r/20251019210450.88830-1-i@rong.moe/
>
> Rong Zhang (6):
>   platform/x86: lenovo-wmi-helpers: convert returned 4B buffer into u32
>   platform/x86: Rename lenovo-wmi-capdata01 to lenovo-wmi-capdata
>   platform/x86: lenovo-wmi-{capdata,other}: Support multiple Capability
>     Data
>   platform/x86: lenovo-wmi-capdata: Add support for Capability Data 00
>   platform/x86: lenovo-wmi-capdata: Add support for Fan Test Data
>   platform/x86: lenovo-wmi-other: Add HWMON for fan speed RPM
>
>  .../wmi/devices/lenovo-wmi-other.rst          |  43 +-
>  drivers/platform/x86/lenovo/Kconfig           |   5 +-
>  drivers/platform/x86/lenovo/Makefile          |   2 +-
>  drivers/platform/x86/lenovo/wmi-capdata.c     | 545 ++++++++++++++++++
>  drivers/platform/x86/lenovo/wmi-capdata.h     |  46 ++
>  drivers/platform/x86/lenovo/wmi-capdata01.c   | 302 ----------
>  drivers/platform/x86/lenovo/wmi-capdata01.h   |  25 -
>  drivers/platform/x86/lenovo/wmi-helpers.c     |  21 +-
>  drivers/platform/x86/lenovo/wmi-other.c       | 501 +++++++++++++++-
>  9 files changed, 1134 insertions(+), 356 deletions(-)
>  create mode 100644 drivers/platform/x86/lenovo/wmi-capdata.c
>  create mode 100644 drivers/platform/x86/lenovo/wmi-capdata.h
>  delete mode 100644 drivers/platform/x86/lenovo/wmi-capdata01.c
>  delete mode 100644 drivers/platform/x86/lenovo/wmi-capdata01.h
>
>
> base-commit: e53642b87a4f4b03a8d7e5f8507fc3cd0c595ea6
> --
> 2.51.0
>

Rong,

Excellent addition. Thank you for your work. I have no regressions on
my devices and no longer have erroneous fans reported on my system
with v2.

For the series,
Tested-by: Derek J. Clark <derekjohn.clark@...il.com>

Thanks,
Derek