Re: [PATCH 2/2] platform/x86: hp-wmi: implement fan keep-alive

["Ilpo Järvinen" <ilpo.jarvinen@linux.intel.com>]

On Thu, 25 Dec 2025, Krishna Chomal wrote:

> The firmware on some HP laptops automatically reverts the fan speed
> control to "Auto" mode after a 120 second timeout window.
> 
> To ensure that the user-selected fan profile (Max/Manual) persists,
> implement a keep-alive mechanism that periodically refreshes the fan
> mode trigger before the timeout occurs.
> 
> - Introduce a delayed workqueue to trigger the fan mode refresh every 90
>   seconds, ensuring the system maintains the correct fan mode setting.
> - Integrate the refresh mechanism into hp_wmi_hwmon_enforce_ctx() to
>   start, update or cancel the keep-alive process based on the current
>   fan mode.
> 
> This ensures that the driver stays in sync with the hardware.
> 
> Tested on: HP Omen 16-wf1xxx (board ID 8C78)
> 
> Signed-off-by: Krishna Chomal <krishna.chomal108@gmail.com>
> ---
>  drivers/platform/x86/hp/hp-wmi.c | 52 +++++++++++++++++++++++++++++---
>  1 file changed, 48 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/platform/x86/hp/hp-wmi.c b/drivers/platform/x86/hp/hp-wmi.c
> index 9fb956ce809a..fbe012e7a342 100644
> --- a/drivers/platform/x86/hp/hp-wmi.c
> +++ b/drivers/platform/x86/hp/hp-wmi.c
> @@ -31,6 +31,7 @@
>  #include <linux/string.h>
>  #include <linux/dmi.h>
>  #include <linux/fixp-arith.h>
> +#include <linux/workqueue.h>
>  
>  MODULE_AUTHOR("Matthew Garrett <mjg59@srcf.ucam.org>");
>  MODULE_DESCRIPTION("HP laptop WMI driver");
> @@ -365,8 +366,15 @@ struct hp_wmi_hwmon_priv {
>  	u8 gpu_delta;
>  	u8 mode;
>  	u8 pwm;
> +	struct delayed_work keep_alive_dwork;
>  };
>  
> +/*
> + * 90s delay to prevent the firmware from resetting fan mode after fixed
> + * 120s timeout
> + */
> +#define KEEP_ALIVE_DELAY	90

For any time related define, please include its unit in the name so a 
person reading code can immediately know it.

> +
>  #define RPM_TO_PWM(rpm, ctx) fixp_linear_interpolate(0, 0, \
>  						(ctx)->max_rpm, U8_MAX, \
>  						clamp_val((rpm), \
> @@ -2073,6 +2081,7 @@ static int __init hp_wmi_bios_setup(struct platform_device *device)
>  static void __exit hp_wmi_bios_remove(struct platform_device *device)
>  {
>  	int i;
> +	struct hp_wmi_hwmon_priv *ctx;
>  
>  	for (i = 0; i < rfkill2_count; i++) {
>  		rfkill_unregister(rfkill2[i].rfkill);
> @@ -2091,6 +2100,10 @@ static void __exit hp_wmi_bios_remove(struct platform_device *device)
>  		rfkill_unregister(wwan_rfkill);
>  		rfkill_destroy(wwan_rfkill);
>  	}
> +
> +	ctx = platform_get_drvdata(device);
> +	if (ctx)
> +		cancel_delayed_work_sync(&ctx->keep_alive_dwork);
>  }
>  
>  static int hp_wmi_resume_handler(struct device *device)
> @@ -2152,6 +2165,8 @@ static struct platform_driver hp_wmi_driver __refdata = {
>  
>  static int hp_wmi_hwmon_enforce_ctx(struct hp_wmi_hwmon_priv *ctx)
>  {
> +	int ret;
> +
>  	if (!ctx)
>  		return -ENODEV;
>  
> @@ -2159,23 +2174,36 @@ static int hp_wmi_hwmon_enforce_ctx(struct hp_wmi_hwmon_priv *ctx)
>  	case PWM_MODE_MAX:
>  		if (is_victus_s_thermal_profile())
>  			hp_wmi_get_fan_count_userdefine_trigger();
> -		return hp_wmi_fan_speed_max_set(1);
> +		ret = hp_wmi_fan_speed_max_set(1);
> +		break;
>  	case PWM_MODE_MANUAL:
>  		if (!is_victus_s_thermal_profile())
>  			return -EOPNOTSUPP;
> -		return hp_wmi_fan_speed_set(ctx, PWM_TO_RPM(ctx->pwm, ctx));
> +		ret = hp_wmi_fan_speed_set(ctx, PWM_TO_RPM(ctx->pwm, ctx));
> +		break;
>  	case PWM_MODE_AUTO:
>  		if (is_victus_s_thermal_profile()) {
>  			hp_wmi_get_fan_count_userdefine_trigger();
> -			return hp_wmi_fan_speed_max_reset(ctx);
> +			ret = hp_wmi_fan_speed_max_reset(ctx);
>  		} else {
> -			return hp_wmi_fan_speed_max_set(0);
> +			ret = hp_wmi_fan_speed_max_set(0);
>  		}
> +		break;
>  	default:
>  		/* shouldn't happen */
>  		return -EINVAL;
>  	}
>  
> +	if (ret < 0)
> +		return ret;
> +
> +	/* Reschedule keep-alive work based on the new state */
> +	if (ctx->mode == PWM_MODE_MAX || ctx->mode == PWM_MODE_MANUAL)
> +		schedule_delayed_work(&ctx->keep_alive_dwork,
> +				      secs_to_jiffies(KEEP_ALIVE_DELAY));
> +	else
> +		cancel_delayed_work_sync(&ctx->keep_alive_dwork);

This is now duplicating the switch/case, just add these to the existing 
cases.

You may want to introduce ret variable already in PATCH 1/2 and add a note 
there that an upcoming change is going to add keep-alive so the return 
value has to be stored temporarily.

> +
>  	return 0;
>  }
>  
> @@ -2321,6 +2349,20 @@ static const struct hwmon_chip_info chip_info = {
>  	.info = info,
>  };
>  
> +static void hp_wmi_hwmon_keep_alive_handler(struct work_struct *work)
> +{
> +	struct delayed_work *dwork;
> +	struct hp_wmi_hwmon_priv *ctx;
> +
> +	dwork = to_delayed_work(work);
> +	ctx = container_of(dwork, struct hp_wmi_hwmon_priv, keep_alive_dwork);
> +	/*
> +	 * Re-apply the current hwmon context settings.
> +	 * NOTE: hp_wmi_hwmon_enforce_ctx will handle the re-scheduling.
> +	 */
> +	hp_wmi_hwmon_enforce_ctx(ctx);

(I only now understand why you named this function like this, and I still 
don't think it's a good name for it as you've other callers besides this 
one real "enforcing" case.)

> +}
> +
>  static int hp_wmi_hwmon_setup_ctx(struct hp_wmi_hwmon_priv *ctx)
>  {
>  	u8 fan_data[128];
> @@ -2377,6 +2419,8 @@ static int hp_wmi_hwmon_init(void)
>  		return PTR_ERR(hwmon);
>  	}
>  
> +	INIT_DELAYED_WORK(&ctx->keep_alive_dwork, hp_wmi_hwmon_keep_alive_handler);
> +	platform_set_drvdata(hp_wmi_platform_dev, ctx);
>  	hp_wmi_hwmon_enforce_ctx(ctx);
>  
>  	return 0;
> 

-- 
 i.