Thinkpad T470s function keys problem

[anders.ostling]

Ubuntu 21.04 on Thinkpad T470s here, works as a charm EXCEPT that the multimedia keys (volume/brightness) does not work as expected.
Used xev to test, and Vol up reports XFAudioRaiseVolume but Vol down and brightness keys reports wrong (none) recognized values. I have tested Windows and they keys works as expected there, so no obvious hardware issue.

[Yellow Pasque]

Sometimes, things like that can be resolved with BIOS updates. I don't know if there's a specific fix for that issue because Lenovo doesn't make it easy to see the updates. They don't make a changelog. You have to to check/click the notes for each individual BIOS release. PAINFUL.