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From: "Rafael J. Wysocki" <rafael@kernel.org>
Date: Wed, 27 Mar 2024 16:34:55 +0100
Message-ID: <CAJZ5v0iogogd+AxL5ZPU-80Nj-nQz4avkymaPRPa4SiJdvBfjg@mail.gmail.com>
Subject: Re: [PATCH] ACPI: thermal_lib: Continue registering thermal zones
 even if trip points fail validation
To: Stephen Horvath <s.horvath@outlook.com.au>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>, Zhang Rui <rui.zhang@intel.com>, Len Brown <lenb@kernel.org>, 
	linux-acpi@vger.kernel.org, linux-kernel@vger.kernel.org
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On Mon, Mar 25, 2024 at 5:44=E2=80=AFAM Stephen Horvath
<s.horvath@outlook.com.au> wrote:
>
> Some laptops where the thermal control is handled by the EC may
> provide trip points that fail the kernels new validation, but still have
> working temperature sensors. An example of this is the Framework 13 AMD.

I believe that this is a regression introduced recently, so would it
be possible to provide a pointer to the commit that introduced it?

> This patch allows the thermal zone to still be registered without trip
> points if the trip points fail validation, allowing the temperature
> sensor to be viewed and used by the user.
>
> Signed-off-by: Stephen Horvath <s.horvath@outlook.com.au>
> ---
>  drivers/acpi/thermal.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/acpi/thermal.c b/drivers/acpi/thermal.c
> index 302dce0b2b50..fd59e41037ec 100644
> --- a/drivers/acpi/thermal.c
> +++ b/drivers/acpi/thermal.c
> @@ -903,8 +903,8 @@ static int acpi_thermal_add(struct acpi_device *devic=
e)
>
>         if (trip =3D=3D trip_table) {
>                 pr_warn(FW_BUG "No valid trip points!\n");
> -               result =3D -ENODEV;
> -               goto free_memory;
> +               /* Effectively disable polling since it is not needed */
> +               tz->polling_frequency =3D 0;

Because the thermal zone becomes effectively tripless, it should be
registered with thermal_tripless_zone_device_register().

>         }
>
>         result =3D acpi_thermal_register_thermal_zone(tz, trip_table,
> --