Re: [PATCH v3] ACPI: fan: Add fan speed reporting for fans with only _FST

[Joshua Grisham]

Den tors 6 feb. 2025 kl 06:05 skrev Armin Wolf <W_Armin@xxxxxx>:
>
> Am 25.01.25 um 11:07 schrieb Joshua Grisham:
>
> > Add support for ACPI fans with _FST to report their speed even if they do
> > not support fan control.
> >
> > As suggested by Armin Wolf [1] and per the Windows Thermal Management
> > Design Guide [2], Samsung Galaxy Book series devices (and possibly many
> > more devices where the Windows guide was strictly followed) only implement
> > the _FST method and do not support ACPI-based fan control.
> >
> > Currently, these fans are not supported by the kernel driver but this patch
> > will make some very small adjustments to allow them to be supported.
> >
> > This patch is tested and working for me on a Samsung Galaxy Book2 Pro whose
> > DSDT (and several other Samsung Galaxy Book series notebooks which
> > currently have the same issue) can be found at [3].
>
> Any updates on this patch? For me it seems ready for mainline.
>
> Thanks,
> Armin Wolf
>

Hi Armin, thanks for checking in on this!

For me I have no further updates that I planned or intended to send.
If it looks good to Rafael or anyone else who wants or needs to review
then I would be glad to see it applied.

If needed then I can re-send with Armin's Reviewed-by tag inline in
the commit message but otherwise everything is as I would have wished
it to be, for what that is worth :)

Thanks again!

Best regards,
Joshua


> >
> > [1]: https://lore.kernel.org/platform-driver-x86/53c5075b-1967-45d0-937f-463912dd966d@xxxxxx
> > [2]: https://learn.microsoft.com/en-us/windows-hardware/design/device-experiences/design-guide
> > [3]: https://github.com/joshuagrisham/samsung-galaxybook-extras/tree/8e3087a06b8bdcdfdd081367af4b744a56cc4ee9/dsdt
> >
> > Signed-off-by: Joshua Grisham <josh@xxxxxxxxxxxxxxxxx>
> > ---
> >
> > v1->v2:
> > - Still allow acpi4_only_fst fans to update power state on
> >    suspend/resume
> > - Fix if / else if logic error
> > - Also hide hwmon_power_input for acpi4_only_fst fans
> >
> > v2->v3:
> > - Still allow acpi4_only_fst fans to set initial power state on probe
> > ---
> >   drivers/acpi/fan.h       |  1 +
> >   drivers/acpi/fan_attr.c  | 37 ++++++++++++++++++++++---------------
> >   drivers/acpi/fan_core.c  | 22 +++++++++++++++++-----
> >   drivers/acpi/fan_hwmon.c | 12 ++++++++++++
> >   4 files changed, 52 insertions(+), 20 deletions(-)
> >
> > diff --git a/drivers/acpi/fan.h b/drivers/acpi/fan.h
> > index 488b51e2c..d0aad88a7 100644
> > --- a/drivers/acpi/fan.h
> > +++ b/drivers/acpi/fan.h
> > @@ -49,6 +49,7 @@ struct acpi_fan_fst {
> >
> >   struct acpi_fan {
> >       bool acpi4;
> > +     bool acpi4_only_fst;
> >       struct acpi_fan_fif fif;
> >       struct acpi_fan_fps *fps;
> >       int fps_count;
> > diff --git a/drivers/acpi/fan_attr.c b/drivers/acpi/fan_attr.c
> > index f4f6e2381..d83f88429 100644
> > --- a/drivers/acpi/fan_attr.c
> > +++ b/drivers/acpi/fan_attr.c
> > @@ -75,15 +75,6 @@ int acpi_fan_create_attributes(struct acpi_device *device)
> >       struct acpi_fan *fan = acpi_driver_data(device);
> >       int i, status;
> >
> > -     sysfs_attr_init(&fan->fine_grain_control.attr);
> > -     fan->fine_grain_control.show = show_fine_grain_control;
> > -     fan->fine_grain_control.store = NULL;
> > -     fan->fine_grain_control.attr.name = "fine_grain_control";
> > -     fan->fine_grain_control.attr.mode = 0444;
> > -     status = sysfs_create_file(&device->dev.kobj, &fan->fine_grain_control.attr);
> > -     if (status)
> > -             return status;
> > -
> >       /* _FST is present if we are here */
> >       sysfs_attr_init(&fan->fst_speed.attr);
> >       fan->fst_speed.show = show_fan_speed;
> > @@ -92,7 +83,19 @@ int acpi_fan_create_attributes(struct acpi_device *device)
> >       fan->fst_speed.attr.mode = 0444;
> >       status = sysfs_create_file(&device->dev.kobj, &fan->fst_speed.attr);
> >       if (status)
> > -             goto rem_fine_grain_attr;
> > +             return status;
> > +
> > +     if (fan->acpi4_only_fst)
> > +             return 0;
> > +
> > +     sysfs_attr_init(&fan->fine_grain_control.attr);
> > +     fan->fine_grain_control.show = show_fine_grain_control;
> > +     fan->fine_grain_control.store = NULL;
> > +     fan->fine_grain_control.attr.name = "fine_grain_control";
> > +     fan->fine_grain_control.attr.mode = 0444;
> > +     status = sysfs_create_file(&device->dev.kobj, &fan->fine_grain_control.attr);
> > +     if (status)
> > +             goto rem_fst_attr;
> >
> >       for (i = 0; i < fan->fps_count; ++i) {
> >               struct acpi_fan_fps *fps = &fan->fps[i];
> > @@ -109,18 +112,18 @@ int acpi_fan_create_attributes(struct acpi_device *device)
> >
> >                       for (j = 0; j < i; ++j)
> >                               sysfs_remove_file(&device->dev.kobj, &fan->fps[j].dev_attr.attr);
> > -                     goto rem_fst_attr;
> > +                     goto rem_fine_grain_attr;
> >               }
> >       }
> >
> >       return 0;
> >
> > -rem_fst_attr:
> > -     sysfs_remove_file(&device->dev.kobj, &fan->fst_speed.attr);
> > -
> >   rem_fine_grain_attr:
> >       sysfs_remove_file(&device->dev.kobj, &fan->fine_grain_control.attr);
> >
> > +rem_fst_attr:
> > +     sysfs_remove_file(&device->dev.kobj, &fan->fst_speed.attr);
> > +
> >       return status;
> >   }
> >
> > @@ -129,9 +132,13 @@ void acpi_fan_delete_attributes(struct acpi_device *device)
> >       struct acpi_fan *fan = acpi_driver_data(device);
> >       int i;
> >
> > +     sysfs_remove_file(&device->dev.kobj, &fan->fst_speed.attr);
> > +
> > +     if (fan->acpi4_only_fst)
> > +             return;
> > +
> >       for (i = 0; i < fan->fps_count; ++i)
> >               sysfs_remove_file(&device->dev.kobj, &fan->fps[i].dev_attr.attr);
> >
> > -     sysfs_remove_file(&device->dev.kobj, &fan->fst_speed.attr);
> >       sysfs_remove_file(&device->dev.kobj, &fan->fine_grain_control.attr);
> >   }
> > diff --git a/drivers/acpi/fan_core.c b/drivers/acpi/fan_core.c
> > index 10016f52f..66aa1be64 100644
> > --- a/drivers/acpi/fan_core.c
> > +++ b/drivers/acpi/fan_core.c
> > @@ -211,6 +211,11 @@ static bool acpi_fan_is_acpi4(struct acpi_device *device)
> >              acpi_has_method(device->handle, "_FST");
> >   }
> >
> > +static bool acpi_fan_has_fst(struct acpi_device *device)
> > +{
> > +     return acpi_has_method(device->handle, "_FST");
> > +}
> > +
> >   static int acpi_fan_get_fif(struct acpi_device *device)
> >   {
> >       struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
> > @@ -327,7 +332,12 @@ static int acpi_fan_probe(struct platform_device *pdev)
> >       device->driver_data = fan;
> >       platform_set_drvdata(pdev, fan);
> >
> > -     if (acpi_fan_is_acpi4(device)) {
> > +     if (acpi_fan_is_acpi4(device))
> > +             fan->acpi4 = true;
> > +     else if (acpi_fan_has_fst(device))
> > +             fan->acpi4_only_fst = true;
> > +
> > +     if (fan->acpi4) {
> >               result = acpi_fan_get_fif(device);
> >               if (result)
> >                       return result;
> > @@ -335,7 +345,9 @@ static int acpi_fan_probe(struct platform_device *pdev)
> >               result = acpi_fan_get_fps(device);
> >               if (result)
> >                       return result;
> > +     }
> >
> > +     if (fan->acpi4 || fan->acpi4_only_fst) {
> >               result = devm_acpi_fan_create_hwmon(device);
> >               if (result)
> >                       return result;
> > @@ -343,9 +355,9 @@ static int acpi_fan_probe(struct platform_device *pdev)
> >               result = acpi_fan_create_attributes(device);
> >               if (result)
> >                       return result;
> > +     }
> >
> > -             fan->acpi4 = true;
> > -     } else {
> > +     if (!fan->acpi4) {
> >               result = acpi_device_update_power(device, NULL);
> >               if (result) {
> >                       dev_err(&device->dev, "Failed to set initial power state\n");
> > @@ -391,7 +403,7 @@ static int acpi_fan_probe(struct platform_device *pdev)
> >   err_unregister:
> >       thermal_cooling_device_unregister(cdev);
> >   err_end:
> > -     if (fan->acpi4)
> > +     if (fan->acpi4 || fan->acpi4_only_fst)
> >               acpi_fan_delete_attributes(device);
> >
> >       return result;
> > @@ -401,7 +413,7 @@ static void acpi_fan_remove(struct platform_device *pdev)
> >   {
> >       struct acpi_fan *fan = platform_get_drvdata(pdev);
> >
> > -     if (fan->acpi4) {
> > +     if (fan->acpi4 || fan->acpi4_only_fst) {
> >               struct acpi_device *device = ACPI_COMPANION(&pdev->dev);
> >
> >               acpi_fan_delete_attributes(device);
> > diff --git a/drivers/acpi/fan_hwmon.c b/drivers/acpi/fan_hwmon.c
> > index bd0d31a39..d0668ecc2 100644
> > --- a/drivers/acpi/fan_hwmon.c
> > +++ b/drivers/acpi/fan_hwmon.c
> > @@ -43,6 +43,12 @@ static umode_t acpi_fan_hwmon_is_visible(const void *drvdata, enum hwmon_sensor_
> >               case hwmon_fan_input:
> >                       return 0444;
> >               case hwmon_fan_target:
> > +                     /*
> > +                      * Fans with only _FST do not support fan control.
> > +                      */
> > +                     if (fan->acpi4_only_fst)
> > +                             return 0;
> > +
> >                       /*
> >                        * When in fine grain control mode, not every fan control value
> >                        * has an associated fan performance state.
> > @@ -57,6 +63,12 @@ static umode_t acpi_fan_hwmon_is_visible(const void *drvdata, enum hwmon_sensor_
> >       case hwmon_power:
> >               switch (attr) {
> >               case hwmon_power_input:
> > +                     /*
> > +                      * Fans with only _FST do not support fan control.
> > +                      */
> > +                     if (fan->acpi4_only_fst)
> > +                             return 0;
> > +
> >                       /*
> >                        * When in fine grain control mode, not every fan control value
> >                        * has an associated fan performance state.