On Tue, Jan 14, 2025 at 2:22 AM Joshua Grisham <josh@xxxxxxxxxxxxxxxxx> wrote: > > 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]. > > [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> > --- > drivers/acpi/fan.h | 1 + > drivers/acpi/fan_attr.c | 37 ++++++++++++++++++++++--------------- > drivers/acpi/fan_core.c | 24 ++++++++++++++++-------- > drivers/acpi/fan_hwmon.c | 6 ++++++ > 4 files changed, 45 insertions(+), 23 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; I would use has_fst instead of this, that is + bool has_fst; which would be true when acpi4 is true, but not necessarily the other way around. > 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; So the above may become if (!fan->acpi4) 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..b51b1481c 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; And here one could do if (acpi_fan_has_fst(device)) { fan->has_fst = true; fan->acpi4 = acpi_fan_is_acpi4(device); } and if I'm not mistaken, the check for _FST presence could be dropped from acpi_fan_is_acpi4(). > + > + if (fan->acpi4) { > result = acpi_fan_get_fif(device); > if (result) > return result; > @@ -335,7 +345,7 @@ static int acpi_fan_probe(struct platform_device *pdev) > result = acpi_fan_get_fps(device); > if (result) > return result; > - > + } else if (fan->acpi4 || fan->acpi4_only_fst) { Then, all of the checks like the above could be replaced with fan->has_fst checks. > result = devm_acpi_fan_create_hwmon(device); > if (result) > return result; > @@ -343,8 +353,6 @@ static int acpi_fan_probe(struct platform_device *pdev) > result = acpi_fan_create_attributes(device); > if (result) > return result; > - > - fan->acpi4 = true; > } else { > result = acpi_device_update_power(device, NULL); > if (result) { > @@ -391,7 +399,7 @@ 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 +409,7 @@ 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); > @@ -415,7 +423,7 @@ static void acpi_fan_remove(struct platform_device *pdev) > static int acpi_fan_suspend(struct device *dev) > { > struct acpi_fan *fan = dev_get_drvdata(dev); > - if (fan->acpi4) > + if (fan->acpi4 || fan->acpi4_only_fst) > return 0; > > acpi_device_set_power(ACPI_COMPANION(dev), ACPI_STATE_D0); > @@ -428,7 +436,7 @@ static int acpi_fan_resume(struct device *dev) > int result; > struct acpi_fan *fan = dev_get_drvdata(dev); > > - if (fan->acpi4) > + if (fan->acpi4 || fan->acpi4_only_fst) > return 0; > > result = acpi_device_update_power(ACPI_COMPANION(dev), NULL); > diff --git a/drivers/acpi/fan_hwmon.c b/drivers/acpi/fan_hwmon.c > index bd0d31a39..87bee018c 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. > + */ Nit: One-line comment here, please. > + if (fan->acpi4_only_fst) And this would become if (!fan->acpi4) > + return 0; > + > /* > * When in fine grain control mode, not every fan control value > * has an associated fan performance state. > --
