Re: [PATCH 5/6] HID: asus: add microphone mute LED support for T3304

[James Ye]

On Mon, 4 May 2026 at 08:45, Denis Benato <denis.benato@xxxxxxxxx> wrote:
> Isn't QUIRK_T3304_KEYBOARD enough? Or are you saying you know there is more than one keyboard
> model that requires this?

I don't know for certain if there are any other such keyboards with
LEDs that need to be handled like this, but I can imagine that there
are.

I decided to introduce an additional quirk because:
- I don't know how to detect if a micmute LED is present.
- The quirk could be used to implement support in other devices.
- asus_kbd_register_leds is also gated by QUIRK_USE_KBD_BACKLIGHT,
adding a device-specific quirk didn't feel appropriate.

If there turns out to be a widely-supported detection method and T330
doesn't support this, then just QUIRK_T3304_KEYBOARD would be better.

If you would prefer then I shall remove QUIRK_HID_MICMUTE. This can be
revisited when more than one device uses this code.

>
> Do we really want to use strlen?
>
> Do we really want to use strlen on the result of a function without additional checks?

My understanding is that this is safe, as this name is set by the
kernel. Existing use of dev_name appears to not involve additional
checks.

> This doesn't look like a good idea to change this for all laptops under the sun...
>
>
> Perhaps might make sense to move this check before? Maybe not?

Returning an error from asus_kbd_register_leds is currently non-fatal,
so the only difference in behaviour is that devices with
QUIRK_USE_KBD_BACKLIGHT that do not report supporting a backlight will
no longer log a warning.

T3304 indeed lacks a backlight, so we can't proceed with the backlight
setup code, but asus_kbd_get_functions() is still a prerequisite for
the micmute LED.

I think the alternative is:
- Move the asus_kbd_get_functions() call site from
asus_kbd_register_leds() to asus_probe(), and
- Separate asus_kbd_register_leds() into two functions for backlight
and micmute LEDs respectively, keeping the current behaviour for
backlight registration.

Your thoughts?

Cheers,
James

>
> Denis