Re: [PATCH v3 5/6] thermal/drivers/acpi: Make cross dev link optional by configuration

[Daniel Lezcano]

On 18/04/2023 15:38, Rafael J. Wysocki wrote:
> On Thu, Apr 13, 2023 at 1:47 PM Daniel Lezcano
> <daniel.lezcano@xxxxxxxxxx> wrote:
> > The ACPI thermal driver creates a link in the thermal zone device
> > sysfs directory pointing to the device sysfs directory. At the same
> > time, it creates a back pointer link from the device to the thermal
> > zone device sysfs directory.
> >
> >  From a generic perspective, having a device pointer in the sysfs
> > thermal zone directory may make sense. But the opposite is not true as
> > the same driver can be related to multiple thermal zones.
> >
> > The usage of these information is very specific to ACPI and it is
> > questionable if they are really needed.
> >
> > Let's make the code optional and disable it by default. If it hurts,
> > we will revert this change.
> >
> > Signed-off-by: Daniel Lezcano <daniel.lezcano@xxxxxxxxxx>
> > ---
> >   drivers/acpi/Kconfig   | 13 +++++++++
> >   drivers/acpi/thermal.c | 62 ++++++++++++++++++++++++++++--------------
> >   2 files changed, 55 insertions(+), 20 deletions(-)
> >
> > diff --git a/drivers/acpi/Kconfig b/drivers/acpi/Kconfig
> > index ccbeab9500ec..7df4e18f06ef 100644
> > --- a/drivers/acpi/Kconfig
> > +++ b/drivers/acpi/Kconfig
> > @@ -336,6 +336,19 @@ config ACPI_THERMAL
> >            To compile this driver as a module, choose M here:
> >            the module will be called thermal.
> >
> > +config ACPI_THERMAL_SYSFS_ADDON
> > +       bool "Enable thermal sysfs addon"
> > +       depends on ACPI_THERMAL
> > +       def_bool n
> > +       help
> > +        Enable sysfs extra information added in the thermal zone and
> > +        the driver specific sysfs directories. That could be a link
> > +        to the associated thermal zone as well as a link pointing to
> > +        the device from the thermal zone. By default those are
> > +        disabled and are candidate for removal, if you need these
> > +        information anyway, enable the option or upgrade the
> > +        userspace program using them.
> > +
>
> I don't think that the Kconfig option is appropriate and the help text
> above isn't really helpful.

I'm sorry, I'm missing something. Don't we want to make these sysfs 
extra information optional and disable them by default ?

> >   config ACPI_PLATFORM_PROFILE
> >          tristate
> >
> > diff --git a/drivers/acpi/thermal.c b/drivers/acpi/thermal.c
> > index 5763db4528b8..30fe189d04f8 100644
> > --- a/drivers/acpi/thermal.c
> > +++ b/drivers/acpi/thermal.c
> > @@ -787,9 +787,44 @@ static struct thermal_zone_device_ops acpi_thermal_zone_ops = {
> >          .critical = acpi_thermal_zone_device_critical,
> >   };
> >
> > +#ifdef CONFIG_ACPI_THERMAL_SYSFS_ADDON
>
> I agree with moving the code in question to separate functions, but I
> don't agree with putting it under the Kconfig option.

Do you mean use IS_ENABLED check like what is done with Menlow patch 6 ?

[ ... ]


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