Re: [PATCH v2] platform/x86: hp-wmi: Add dual-channel PWM fan control for Victus S

[Krishna Chomal <krishna.chomal108@gmail.com>]

On Sun, May 31, 2026 at 12:23:26PM +0300, 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@kursatabayli.dev>
>---
>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 | 57 ++++++++++++++++----------------
> 1 file changed, 28 insertions(+), 29 deletions(-)
>
>diff --git a/drivers/platform/x86/hp/hp-wmi.c b/drivers/platform/x86/hp/hp-wmi.c
>index f63bc00d9a9b..51611dd2220f 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 +817,15 @@ 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;
>-
>-	fan_speed[CPU_FAN] = speed;
>-	fan_speed[GPU_FAN] = speed;
>+	int ret;
>
>-	/*
>-	 * 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);
>-	}
>+	fan_speed[CPU_FAN] = (priv->cpu_pwm == HP_FAN_SPEED_AUTOMATIC) ?
>+	HP_FAN_SPEED_AUTOMATIC : pwm_to_rpm(priv->cpu_pwm, priv);
>+	fan_speed[GPU_FAN] = (priv->gpu_pwm == HP_FAN_SPEED_AUTOMATIC) ?
>+	HP_FAN_SPEED_AUTOMATIC : pwm_to_rpm(priv->gpu_pwm, priv);

These ternary expressions are a bit hard to read with the line
wrappings. Let's expand them into standard if-else blocks for better
readability.

>
> 	ret = hp_wmi_get_fan_count_userdefine_trigger();
> 	if (ret < 0)
>@@ -851,7 +842,9 @@ 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 +2395,7 @@ 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 +2495,14 @@ 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 +2512,10 @@ 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 == 0)
>+				priv->cpu_pwm = rpm_to_pwm(rpm, priv);
>+			else
>+				priv->gpu_pwm = rpm_to_pwm(rpm, priv);

Please use the CPU_FAN and GPU_FAN macros here instead of hardcoding 0
or 1. It makes the channel mapping more explicit.

> 			return hp_wmi_apply_fan_settings(priv);
> 		}
> 		switch (val) {
>@@ -2532,10 +2529,14 @@ 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);
> 			priv->mode = PWM_MODE_MANUAL;
> 			return hp_wmi_apply_fan_settings(priv);
> 		case PWM_MODE_AUTO:
>@@ -2551,7 +2552,7 @@ 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 +2593,7 @@ 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 +2639,8 @@ 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;
> }
>-- 
>2.54.0
>