Re: [PATCH v3] platform/x86: hp-wmi: Add dual-channel PWM fan control for Victus S

[Ilpo Järvinen]

On Sun, 31 May 2026, Kürşat Abaylı wrote:

> Currently, manual fan control on supported Victus S models uses a single
> PWM value for both CPU and GPU fans, linking their speeds via a hardcoded
> gpu_delta offset. This prevents userspace tools from managing the thermal
> profiles of the CPU and GPU independently.
> 
> Refactor the hwmon implementation to support independent dual-channel
> PWM control:
> - Split the single 'pwm' state into 'cpu_pwm' and 'gpu_pwm'.
> - Expose a second PWM channel ('pwm2') to userspace via hwmon_channel_info.
> - Remove the gpu_delta mechanism entirely.
> 
> The 'pwm1_enable' mode remains shared, as the underlying hardware does
> not support per-fan modes. When switching to manual mode, both fans are
> smoothly initialized to their current RPMs. Additionally, ensure that
> the HP_FAN_SPEED_AUTOMATIC flag is isolated from rpm_to_pwm mathematical
> interpolations during mode resets to prevent unintended fan states.
> 
> Tested on: HP Victus 16-s0xxx
> 
> Signed-off-by: Kürşat Abaylı <hello@xxxxxxxxxxxxxxxx>
> 
> ---
> Changes in v3:
> - Addressed review feedback from Krishna Chomal:
>   - Expanded ternary operators in hp_wmi_fan_speed_set to standard if-else blocks.
>   - Replaced hardcoded channel numbers with CPU_FAN and GPU_FAN macros.
> 
> Changes in v2:
> - Made RPM readings atomic during the transition to manual mode.
> - Fixed a variable scoping issue in the pwm_input block.
> ---
> ---
>  drivers/platform/x86/hp/hp-wmi.c | 60 +++++++++++++++++---------------
>  1 file changed, 32 insertions(+), 28 deletions(-)
> 
> diff --git a/drivers/platform/x86/hp/hp-wmi.c b/drivers/platform/x86/hp/hp-wmi.c
> index f63bc00d9a9b..cef0c4436bd0 100644
> --- a/drivers/platform/x86/hp/hp-wmi.c
> +++ b/drivers/platform/x86/hp/hp-wmi.c
> @@ -488,9 +488,9 @@ struct hp_wmi_hwmon_priv {
>  	struct mutex lock;	/* protects mode, pwm */
>  	u8 min_rpm;
>  	u8 max_rpm;
> -	int gpu_delta;
>  	u8 mode;
> -	u8 pwm;
> +	u8 cpu_pwm;
> +	u8 gpu_pwm;
>  	struct delayed_work keep_alive_dwork;
>  };
>  
> @@ -817,24 +817,20 @@ static int hp_wmi_fan_speed_max_set(int enabled)
>  	return enabled;
>  }
>  
> -static int hp_wmi_fan_speed_set(struct hp_wmi_hwmon_priv *priv, u8 speed)
> +static int hp_wmi_fan_speed_set(struct hp_wmi_hwmon_priv *priv)
>  {
>  	u8 fan_speed[2];
> -	int gpu_speed, ret;
> +	int ret;
>  
> -	fan_speed[CPU_FAN] = speed;
> -	fan_speed[GPU_FAN] = speed;
> +	if (priv->cpu_pwm == HP_FAN_SPEED_AUTOMATIC)
> +		fan_speed[CPU_FAN] = HP_FAN_SPEED_AUTOMATIC;
> +	else
> +		fan_speed[CPU_FAN] = pwm_to_rpm(priv->cpu_pwm, priv);
>  
> -	/*
> -	 * GPU fan speed is always a little higher than CPU fan speed, we fetch
> -	 * this delta value from the fan table during hwmon init.
> -	 * Exception: Speed is set to HP_FAN_SPEED_AUTOMATIC, to revert to
> -	 * automatic mode.
> -	 */
> -	if (speed != HP_FAN_SPEED_AUTOMATIC) {
> -		gpu_speed = speed + priv->gpu_delta;
> -		fan_speed[GPU_FAN] = clamp_val(gpu_speed, 0, U8_MAX);
> -	}
> +	if (priv->gpu_pwm == HP_FAN_SPEED_AUTOMATIC)
> +		fan_speed[GPU_FAN] = HP_FAN_SPEED_AUTOMATIC;
> +	else
> +		fan_speed[GPU_FAN] = pwm_to_rpm(priv->gpu_pwm, priv);
>  
>  	ret = hp_wmi_get_fan_count_userdefine_trigger();
>  	if (ret < 0)
> @@ -851,7 +847,9 @@ static int hp_wmi_fan_speed_set(struct hp_wmi_hwmon_priv *priv, u8 speed)
>  
>  static int hp_wmi_fan_speed_reset(struct hp_wmi_hwmon_priv *priv)
>  {
> -	return hp_wmi_fan_speed_set(priv, HP_FAN_SPEED_AUTOMATIC);
> +	priv->cpu_pwm = HP_FAN_SPEED_AUTOMATIC;
> +	priv->gpu_pwm = HP_FAN_SPEED_AUTOMATIC;
> +	return hp_wmi_fan_speed_set(priv);
>  }
>  
>  static int hp_wmi_fan_speed_max_reset(struct hp_wmi_hwmon_priv *priv)
> @@ -2402,7 +2400,7 @@ static int hp_wmi_apply_fan_settings(struct hp_wmi_hwmon_priv *priv)
>  	case PWM_MODE_MANUAL:
>  		if (!is_victus_s_thermal_profile())
>  			return -EOPNOTSUPP;
> -		ret = hp_wmi_fan_speed_set(priv, pwm_to_rpm(priv->pwm, priv));
> +		ret = hp_wmi_fan_speed_set(priv);
>  		if (ret < 0)
>  			return ret;
>  		mod_delayed_work(system_wq, &priv->keep_alive_dwork,
> @@ -2502,13 +2500,14 @@ static int hp_wmi_hwmon_write(struct device *dev, enum hwmon_sensor_types type,
>  			      u32 attr, int channel, long val)
>  {
>  	struct hp_wmi_hwmon_priv *priv;
> -	int rpm;
> +	int cpu_rpm, gpu_rpm;
>  
>  	priv = dev_get_drvdata(dev);
>  	guard(mutex)(&priv->lock);
>  	switch (type) {
>  	case hwmon_pwm:
>  		if (attr == hwmon_pwm_input) {
> +			int rpm;
>  			if (!is_victus_s_thermal_profile())
>  				return -EOPNOTSUPP;
>  			/* PWM input is invalid when not in manual mode */
> @@ -2518,7 +2517,10 @@ static int hp_wmi_hwmon_write(struct device *dev, enum hwmon_sensor_types type,
>  			/* ensure PWM input is within valid fan speeds */
>  			rpm = pwm_to_rpm(val, priv);
>  			rpm = clamp_val(rpm, priv->min_rpm, priv->max_rpm);
> -			priv->pwm = rpm_to_pwm(rpm, priv);
> +			if (channel == CPU_FAN)
> +				priv->cpu_pwm = rpm_to_pwm(rpm, priv);
> +			else if (channel == GPU_FAN)
> +				priv->gpu_pwm = rpm_to_pwm(rpm, priv);
>  			return hp_wmi_apply_fan_settings(priv);
>  		}
>  		switch (val) {
> @@ -2532,10 +2534,14 @@ static int hp_wmi_hwmon_write(struct device *dev, enum hwmon_sensor_types type,
>  			 * When switching to manual mode, set fan speed to
>  			 * current RPM values to ensure a smooth transition.
>  			 */
> -			rpm = hp_wmi_get_fan_speed_victus_s(channel);
> -			if (rpm < 0)
> -				return rpm;
> -			priv->pwm = rpm_to_pwm(rpm / 100, priv);
> +			cpu_rpm = hp_wmi_get_fan_speed_victus_s(CPU_FAN);
> +			if (cpu_rpm < 0)
> +				return cpu_rpm;
> +			gpu_rpm = hp_wmi_get_fan_speed_victus_s(GPU_FAN);
> +			if (gpu_rpm < 0)
> +				return gpu_rpm;
> +			priv->cpu_pwm = rpm_to_pwm(cpu_rpm / 100, priv);
> +			priv->gpu_pwm = rpm_to_pwm(gpu_rpm / 100, priv);

Could you please rebase this patch, it no longer applies cleanly and I was 
unsure of what is the correct resolution.

Please also add Radhey's Tested-by tag while preparing the next version.

--
 i.

>  			priv->mode = PWM_MODE_MANUAL;
>  			return hp_wmi_apply_fan_settings(priv);
>  		case PWM_MODE_AUTO:
> @@ -2551,7 +2557,7 @@ static int hp_wmi_hwmon_write(struct device *dev, enum hwmon_sensor_types type,
>  
>  static const struct hwmon_channel_info * const info[] = {
>  	HWMON_CHANNEL_INFO(fan, HWMON_F_INPUT, HWMON_F_INPUT),
> -	HWMON_CHANNEL_INFO(pwm, HWMON_PWM_ENABLE | HWMON_PWM_INPUT),
> +	HWMON_CHANNEL_INFO(pwm, HWMON_PWM_ENABLE | HWMON_PWM_INPUT, HWMON_PWM_INPUT),
>  	NULL
>  };
>  
> @@ -2592,7 +2598,7 @@ static int hp_wmi_setup_fan_settings(struct hp_wmi_hwmon_priv *priv)
>  	struct victus_s_fan_table *fan_table;
>  	u8 min_rpm, max_rpm;
>  	u8 cpu_rpm, gpu_rpm, noise_db;
> -	int gpu_delta, i, num_entries, ret;
> +	int i, num_entries, ret;
>  	size_t header_size, entry_size;
>  
>  	/* Default behaviour on hwmon init is automatic mode */
> @@ -2638,10 +2644,8 @@ static int hp_wmi_setup_fan_settings(struct hp_wmi_hwmon_priv *priv)
>  	if (min_rpm == U8_MAX || max_rpm == 0)
>  		return -EINVAL;
>  
> -	gpu_delta = fan_table->entries[0].gpu_rpm - fan_table->entries[0].cpu_rpm;
>  	priv->min_rpm = min_rpm;
>  	priv->max_rpm = max_rpm;
> -	priv->gpu_delta = gpu_delta;
>  
>  	return 0;
>  }
>