I'm a very happy Xubuntu user on a HP Probook 430G6.
So I bought another one.
On that 2nd notebook (identical hardware, and identical Xubuntu version (20.04.1)) the Brightness +/- keys weren't working: They were togging the Microphone (Same as Fn+F8)
[SOLUTION]
I suspected the mismatching BIOS versions, but I was wrong:
Normal brightness-key-behavior can be restored with a "HP Power Reset"!
https://support.hp.com/sg-en/document/i ... 1551050-16
Summary:
* Unplug everything (!) from your Notebook.
* Press and hold the power-key for at least 15 seconds.
* Then release. Wait a few seconds.
* Then reconnect power and turn the Notebook back on.
Seems that Windows 10/11 is "leaving some quirky config behind" - in the EFI BIOS area...
I don't do dual-boot with Windows anymore, so this fixes it.
However, some users have reported, that every time they boot Windows, the Brightness-Keys are messed up again.
Thanks Microsoft for your usual standards-compliance.
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