Re: [PATCH v3 1/1] platform/x86: asus-armoury: gate PPT writes behind active fan curve

[Denis Benato <denis.benato@linux.dev>]

On 5/19/26 20:12, Ahmed Yaseen wrote:
> On models flagged with requires_fan_curve in the DMI power_data table
> (30 entries), the BIOS ACPI method SPLX only writes PPT values to the
> EC when the fan mode is set to Manual (FANM=4). FANM is set to 4 by
> the DEFC method when a custom fan curve is written. Without an active
> custom fan curve, the WMI DEVS call returns success but the firmware
> silently ignores the PPT value, so userspace observes no effect from
> its write.
>
> Gate writes to ASUS_WMI_DEVID_PPT_{PL1_SPL,PL2_SPPT,PL3_FPPT,APU_SPPT,
> PLAT_SPPT} on a check of asus_wmi_custom_fan_curve_is_enabled(), and
> return -EBUSY with a pr_warn_once() when no fan curve is active on an
> affected model. Export the helper from asus-wmi so asus-armoury can
> call it across module boundaries.
Reviewed-by: Denis Benato <denis.benato@linux.dev>
> Signed-off-by: Ahmed Yaseen <yaseen@ghoul.dev>
> ---
>  drivers/platform/x86/asus-armoury.c        | 20 ++++++++++++++++++
>  drivers/platform/x86/asus-wmi.c            | 24 ++++++++++++++++++++++
>  include/linux/platform_data/x86/asus-wmi.h |  5 +++++
>  3 files changed, 49 insertions(+)
>
> diff --git a/drivers/platform/x86/asus-armoury.c b/drivers/platform/x86/asus-armoury.c
> index 5b0987ccc270..f094b70fa1f0 100644
> --- a/drivers/platform/x86/asus-armoury.c
> +++ b/drivers/platform/x86/asus-armoury.c
> @@ -93,6 +93,8 @@ struct asus_armoury_priv {
>  
>  	u32 mini_led_dev_id;
>  	u32 gpu_mux_dev_id;
> +
> +	bool requires_fan_curve;
>  };
>  
>  static struct asus_armoury_priv asus_armoury = {
> @@ -216,6 +218,22 @@ static int armoury_set_devstate(struct kobj_attribute *attr,
>  	u32 result;
>  	int err;
>  
> +	/* On some models, PPT changes require an active fan curve */
> +	if (asus_armoury.requires_fan_curve) {
> +		switch (dev_id) {
> +		case ASUS_WMI_DEVID_PPT_PL1_SPL:
> +		case ASUS_WMI_DEVID_PPT_PL2_SPPT:
> +		case ASUS_WMI_DEVID_PPT_PL3_FPPT:
> +		case ASUS_WMI_DEVID_PPT_APU_SPPT:
> +		case ASUS_WMI_DEVID_PPT_PLAT_SPPT:
> +			if (!asus_wmi_custom_fan_curve_is_enabled()) {
> +				pr_warn_once("PPT change requires an active fan curve on this model. Enable a custom fan curve first.\n");
> +				return -EBUSY;
> +			}
> +			break;
> +		}
> +	}
> +
>  	/*
>  	 * Prevent developers from bricking devices or issuing dangerous
>  	 * commands that can be difficult or impossible to recover from.
> @@ -1002,6 +1020,8 @@ static void init_rog_tunables(void)
>  		return;
>  	}
>  
> +	asus_armoury.requires_fan_curve = power_data->requires_fan_curve;
> +
>  	/* Initialize AC power tunables */
>  	ac_limits = power_data->ac_data;
>  	if (ac_limits) {
> diff --git a/drivers/platform/x86/asus-wmi.c b/drivers/platform/x86/asus-wmi.c
> index 80144c412b90..e4c1716d9b30 100644
> --- a/drivers/platform/x86/asus-wmi.c
> +++ b/drivers/platform/x86/asus-wmi.c
> @@ -4001,6 +4001,30 @@ static int asus_wmi_custom_fan_curve_init(struct asus_wmi *asus)
>  	return 0;
>  }
>  
> +/*
> + * Returns true if at least one custom fan curve is active
> + *
> + * Used by asus-armoury to check if PPT writes will be accepted by the BIOS
> + * on models that require an active fan curve for TDP changes.
> + */
> +bool asus_wmi_custom_fan_curve_is_enabled(void)
> +{
> +	struct fan_curve_data *curves;
> +	struct asus_wmi *asus;
> +
> +	guard(spinlock_irqsave)(&asus_ref.lock);
> +	asus = asus_ref.asus;
> +	if (!asus)
> +		return false;
> +
> +	curves = asus->custom_fan_curves;
> +
> +	return (asus->cpu_fan_curve_available && curves[FAN_CURVE_DEV_CPU].enabled) ||
> +	       (asus->gpu_fan_curve_available && curves[FAN_CURVE_DEV_GPU].enabled) ||
> +	       (asus->mid_fan_curve_available && curves[FAN_CURVE_DEV_MID].enabled);
> +}
> +EXPORT_SYMBOL_NS_GPL(asus_wmi_custom_fan_curve_is_enabled, "ASUS_WMI");
> +
>  /* Throttle thermal policy ****************************************************/
>  static int throttle_thermal_policy_write(struct asus_wmi *asus)
>  {
> diff --git a/include/linux/platform_data/x86/asus-wmi.h b/include/linux/platform_data/x86/asus-wmi.h
> index 554f41b827e1..5d57293ced6c 100644
> --- a/include/linux/platform_data/x86/asus-wmi.h
> +++ b/include/linux/platform_data/x86/asus-wmi.h
> @@ -196,6 +196,7 @@ int asus_wmi_evaluate_method(u32 method_id, u32 arg0, u32 arg1, u32 *retval);
>  int asus_hid_register_listener(struct asus_hid_listener *cdev);
>  void asus_hid_unregister_listener(struct asus_hid_listener *cdev);
>  int asus_hid_event(enum asus_hid_event event);
> +bool asus_wmi_custom_fan_curve_is_enabled(void);
>  #else
>  static inline void set_ally_mcu_hack(enum asus_ally_mcu_hack status)
>  {
> @@ -227,6 +228,10 @@ static inline int asus_hid_event(enum asus_hid_event event)
>  {
>  	return -ENODEV;
>  }
> +static inline bool asus_wmi_custom_fan_curve_is_enabled(void)
> +{
> +	return false;
> +}
>  #endif
>  
>  #endif	/* __PLATFORM_DATA_X86_ASUS_WMI_H */