Re: [PATCH v2 3/5] platform/x86: hp-wmi: use mod_delayed_work to reset keep-alive timer

[Ilpo Järvinen]

On Sun, 22 Mar 2026, Emre Cecanpunar wrote:

> The keep-alive mechanism re-applies fan settings every 90 seconds to
> prevent the firmware from reverting to automatic mode after its 120 s
> timeout. Fan settings are also applied immediately when the user writes
> to the hwmon sysfs interface.
> 
> schedule_delayed_work() is a no-op when the work item is already
> pending. If the user updates fan settings at T=85s, the keep-alive
> still fires at T=90s (5 s after the update) instead of 90 s later.
> This shortens the effective keep-alive window and may allow the
> firmware timeout to expire between cycles.

Hi,

Unfortunately, I don't understand this explanation.

Won't the keepalive expiry at T=90s just result in adding the next 
keepaline event to T=90s + 90s, and the resulting intervals never exceeds 
120s?

It may be inefficient to apply fan settings at T=85s and then fire 
keepalive at T=90s, that much I can see but if you think there's a problem 
beyond that, this explanation doesn't convince me so please elaborate.

If the only problem is inefficiency, this explanation did not convey 
that meaning so in that case, please rephrase.

> Replace schedule_delayed_work() with mod_delayed_work() in both the
> PWM_MODE_MAX and PWM_MODE_MANUAL cases. mod_delayed_work() resets the
> delay to KEEP_ALIVE_DELAY_SECS from the time of each call, whether or
> not the work is already pending, ensuring each user action and each
> keep-alive expiry restarts the full 90 s window.
> 
> Signed-off-by: Emre Cecanpunar <emreleno@xxxxxxxxx>
> ---
>  drivers/platform/x86/hp/hp-wmi.c | 8 ++++----
>  1 file changed, 4 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/platform/x86/hp/hp-wmi.c b/drivers/platform/x86/hp/hp-wmi.c
> index 41769c0861e5..a29f34588055 100644
> --- a/drivers/platform/x86/hp/hp-wmi.c
> +++ b/drivers/platform/x86/hp/hp-wmi.c
> @@ -2342,8 +2342,8 @@ static int hp_wmi_apply_fan_settings(struct hp_wmi_hwmon_priv *priv)
>  		ret = hp_wmi_fan_speed_max_set(1);
>  		if (ret < 0)
>  			return ret;
> -		schedule_delayed_work(&priv->keep_alive_dwork,
> -				      secs_to_jiffies(KEEP_ALIVE_DELAY_SECS));
> +		mod_delayed_work(system_wq, &priv->keep_alive_dwork,
> +				 secs_to_jiffies(KEEP_ALIVE_DELAY_SECS));
>  		return 0;
>  	case PWM_MODE_MANUAL:
>  		if (!is_victus_s_thermal_profile())
> @@ -2351,8 +2351,8 @@ static int hp_wmi_apply_fan_settings(struct hp_wmi_hwmon_priv *priv)
>  		ret = hp_wmi_fan_speed_set(priv, pwm_to_rpm(priv->pwm, priv));
>  		if (ret < 0)
>  			return ret;
> -		schedule_delayed_work(&priv->keep_alive_dwork,
> -				      secs_to_jiffies(KEEP_ALIVE_DELAY_SECS));
> +		mod_delayed_work(system_wq, &priv->keep_alive_dwork,
> +				 secs_to_jiffies(KEEP_ALIVE_DELAY_SECS));
>  		return 0;
>  	case PWM_MODE_AUTO:
>  		if (is_victus_s_thermal_profile()) {
> 

-- 
 i.