Re: [PATCH v10 00/11] HID: asus: Fix ASUS ROG Laptop's Keyboard backlight handling

Denis Benato
2025-11-26T19:57:12Z

On 11/26/25 18:34, Hans de Goede wrote:
> Hi,
>
> On 26-Nov-25 4:23 PM, Ilpo Järvinen wrote:
>> On Wed, 26 Nov 2025, Antheas Kapenekakis wrote:
> ...
>
>>> As for "HID: asus: early return for ROG devices" changing the name of
>>> the devices of this driver, I will veto backporting it if it happens,
>>> so inputplumber will have the two full months to remove the name
>>> match. This is not a breaking change in the sense that software cannot
>>> be made to work on both previous and latter versions and there is no
>>> other software to my knowledge relying on name matches for Asus
>>> keyboards.
>> Did Hans give some opinion about this rename earlier, at least I don't
>> remember nor could find from lore archives?
> I don't remember commenting on this myself either.
>
> So generally speaking there are plenty of cases where /dev/input/event#
> nodes for a specific device have their name changed by some kernel patches.
>
> Typically HID input devices are matched in userspace by their
> bus:vend-id:prod-id triplet not by the name. The name might even
> change by a fwupdate of the device itself.
>
> So I'm not overly worried about this and inputplumber seems nice
> enough and already is very much not a plug-and-play tool.
>
> One possible concern with laptop keyboard input-device name changes
> though is hwdb entries to fixup scancode -> ev-key-code mappings.
>
> See: /lib/udev/hwdb.d/60-keyboard.hwdb on any standard Linux systems
> an then the big comment at the top.
>
> An input-device name change might break this match pattern:
>
> # - Input driver device name and DMI data match:
> # evdev:name: :dmi:bvn*:bvr*:bd*:svn<vendor>:pn*
> # is the name device specified by the
> # driver, <vendor> is the firmware-provided string exported
> # by the kernel DMI modalias, see /sys/class/dmi/id/modalias
>
> As well as the extended version of this and for laptops with USB
> keyboards this is the only match type which allows a DMI match
> which is what we want for laptop kbd mappings. Looking at the Asus
> section of the upstream 60-keyboard.hwdb I do not see any such
> matches though.
>
> There not being such matches kinda make sense since for USB-HID
> devices any special scancode -> ev-key-code mappings are typically
> handled in a vendor specific HID driver like hid-asus.
>
> TL;DR: I think that the input-device name should be fine.
Thank you very much for this write-up! Now I feel much more confident
in giving approval!
> Regards,
>
> Hans
Thank you,
Denis