Re: [PATCH v4] platform/x86: asus-wmi: Ignore unusable kbd backlight WMI device on ROG Strix G814FP

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

14 nov 2026 01:50:29 Aspecky <tarrihmoad@proton.me>:

> On Thursday, November 12th, 2026 at 10:21 AM, Denis Benato <denis.benato@linux.dev> wrote:
>
>>> On the ASUS ROG Strix G18 G814FP, writing a level to the keyboard
>>> backlight brightness in sysfs works, but reading it back always gives
>>> 0, and the read makes the Fn brightness keys misbehave.
>>
>> With "works" do you mean the write report success but does nothing or
>> that it is actually changing the brightness?
>
> Sorry about the confusion, the write does actually change the brightness.
> Writing 3 to /sys/class/leds/asus::kbd_backlight/brightness turns the
> LEDs to high. asus-wmi passes the level both to the WMI device and to
> hid-asus, the latter is the one that registers as a listener on the LED.
> The DEVS(0x00050021) write to the WMI device fails with -ENODEV and
> changes nothing, hid-asus is what actually sets the LEDs:
>

No, you excuse me: the question was not well expressed.

I meant if wmi actually changes something, not if the sysfs write does... From this answer I understand. Keep the description this way.


Do as if I never said anything about this :)

> sysfs write -> asus-wmi |- DEVS(0x00050021) -> firmware -> rejected
>                         |_ hid-asus -> USB HID report -> LEDs
>
>>> DSTS(0x00050021) always returns 0x50000, which is level 0
>>
>> Always returns level zero with the presence bit set.
>
> Correct, always returns level zero with the presence bit set,
> i'll say that in v5.
>
>>> As a side effect, the kbd_rgb_mode and kbd_rgb_mode_index attributes are
>>> no longer created on this board, they never worked here since the firmware
>>> rejects those writes as well.
>>
>> Isn't this a contraddiction to what is written above? That writes
>> actually succeeds?
>
> It's not a contradiction, the sysfs brightness write succeeds because
> of hid-asus, while the WMI DEVS(0x00050021) writes are rejected and
> so are the ones behind kbd_rgb_mode. The commit message doesn't make
> that clear, I'll reword it in v5 and wait a day or so in case there
> are more comments.
>

All good. I understand, proceed mentioning the presence bit and level zero and you're done.

Put a Reviewed-by: Denis Benato <denis.benato@linux.dev> in your next patch.

Thanks,
Denis

> Thanks,
> Moad