Re: [PATCH] platform/x86: asus-wmi: write the thermal policy only when it changes

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

11 nov 2026 22:44:03 Andrei Rusu de Castro <arc@empyreal.works>:

> On the ROG Flow Z13 (GZ302EA), writing the throttle thermal policy makes
> the firmware re-apply its own package power limits for that mode, also
> when the written mode is the one already set. Userspace re-asserts the
> current platform profile on events such as AC plug and unplug, so power
> limits tuned after a profile change are silently replaced by the
> firmware's table for the unchanged mode.

Hi Andrei,

Thanks for spotting this!

> 
> Remember whether the firmware is known to be in the cached mode and skip
> the WMI call in the platform_profile handler when the requested profile
> matches it. A failed write clears that state, and so does restore from
> hibernation, where the firmware starts afresh, so the next profile write
> reaches it again. The throttle_thermal_policy attribute and the fan
> curve reset still write the mode every time.

I don't agree with this: if the userspace requests a power profile change the driver must honor that request.

The core issue here is not the application of the requested power profile but the fact that asus-armoury can get out-of-sync with what is set versus what is reported.

I would suggest fixing that issue instead: when the platform profile is changed, if a custom tdp is set you should make limits re-apply (or, perhaps even easier, reflect the fact custom TDP got disabled, albeit I am not sure this is true for every laptop and I highly doubt that).

This way the kernel honors requests from the user without reporting false information, with the added bonus that even if the profile switched (without unplugging/plugging in the laptop) the reported status is faithful.

Best regards,
Denis B.

> 
> On a GZ302EA running 7.4-rc2 with this change, re-asserting the current
> profile, as happens on AC unplug, leaves package power limits set from
> userspace in place.
> 
> An LLM assisted with finding the cause, writing this change and its
> description, and running the test above on my GZ302EA.
> 
> Signed-off-by: Andrei Rusu de Castro <arc@empyreal.works>
> ---
> drivers/platform/x86/asus-wmi.c | 17 +++++++++++++++++
> 1 file changed, 17 insertions(+)
> 
> diff --git a/drivers/platform/x86/asus-wmi.c b/drivers/platform/x86/asus-wmi.c
> index b33ebdb21..4f37a83c2 100644
> --- a/drivers/platform/x86/asus-wmi.c
> +++ b/drivers/platform/x86/asus-wmi.c
> @@ -315,6 +315,8 @@ struct asus_wmi {
> 
>     u8 throttle_thermal_policy_mode;
>     u32 throttle_thermal_policy_dev;
> +   /* the firmware is known to be in throttle_thermal_policy_mode */
> +   bool throttle_thermal_policy_synced;
> 
>     bool cpu_fan_curve_available;
>     bool gpu_fan_curve_available;
> @@ -4183,9 +4185,11 @@ static int throttle_thermal_policy_write(struct asus_wmi *asus)
>             "throttle_thermal_policy");
> 
>     if (err) {
> +       asus->throttle_thermal_policy_synced = false;
>         pr_warn("Failed to set throttle thermal policy: %d\n", err);
>         return err;
>     }
> +   asus->throttle_thermal_policy_synced = true;
> 
>     /* Must set to disabled if mode is toggled */
>     if (asus->cpu_fan_curve_available)
> @@ -4302,6 +4306,16 @@ static int asus_wmi_platform_profile_set(struct device *dev,
>         return -EOPNOTSUPP;
>     }
> 
> +   /*
> +    * Write the mode only when it changes. The firmware applies its whole
> +    * power table for a mode each time the mode is written, replacing
> +    * package power limits tuned since then (ROG Flow Z13 GZ302EA), and
> +    * userspace re-asserts the current profile on power-supply events.
> +    */
> +   if (asus->throttle_thermal_policy_synced &&
> +       asus->throttle_thermal_policy_mode == tp)
> +       return 0;
> +
>     asus->throttle_thermal_policy_mode = tp;
>     return throttle_thermal_policy_write(asus);
> }
> @@ -5404,6 +5418,9 @@ static int asus_hotk_restore(struct device *device)
>     struct asus_wmi *asus = dev_get_drvdata(device);
>     int bl;
> 
> +   /* The firmware booted afresh; the next profile write must reach it. */
> +   asus->throttle_thermal_policy_synced = false;
> +
>     /* Refresh both wlan rfkill state and pci hotplug */
>     if (asus->wlan.rfkill)
>         asus_rfkill_hotplug(asus);
> -- 
> 2.56.0