A friend has a new notebook, Medion Akoya P6685 with Ubuntu 18.10 (also tried Fedora, Manjaro and others). The bug appears independent of using X or Wayland. We also tried using a newer kernel (4.20.11).

When I click on the Mute or Increase/Decrease volume (Fn+F10..12) button, it appears to be stuck and triggered very often (i.e. mute flickers or volume goes to 0/100). After that, these buttons appear to be broken and the keyboard sometimes does no longer work (until reboot).
This only happens when I use the Fn Keys from the laptop. When I use an external USB keyboard (with dedicated volume buttons), the bug does not appear.

I think the keys seem to get recognized correctly by the kernel (see evtest) but not by X (see xev).

Does anyone have an idea how to fix this issue or at least to disable these function keys?

Here is a video where I press the keys with some logs open:
http://sendvid.com/8j4ofehd

I can update additional logs if you want, but all logs (journalctl, dmesg, xev, evtest, xorg in video) seem to show no problem. Some extra logs:

• xinput
• lspci -vv
• lsusb -v
• name -a

what does xev register, esp. when the "flickering" occurs?

xev doesn't report anything (except the FocusOut event), c.f. top right terminal in the video :/

Thank you for your answer

xev doesn't report anything except the FocusOut event, please see top right terminal in the video.

(Sorry for 2nd post, first one was not posted due to link I think.)

sorry, i don't understand what that means.
can you show some representative output (probably not all of it)?
i don't understand "c.f." and i do not see any video. sorry.

some general advice:

• take your time to produce a meaningful problem description. this also helps you to understand the problem better and get 50% closer to a solution. videos don't usually help. you diligently posted some command output, but unless someone goes "aha, keyboards with that vendor/model ID always have this problem!" i don't see how it's going to help.
• medion laptops are often rebranded form some other brand. try to find out which, that will help you to search better. maybe this helps.
• why ubuntu 18.10??? it's a sort of beta version. the laptop isn't so new anymore, i believe 18.04 is totally sufficient

on a wild guess i'd say undo all the stuff you did and try to fix it as an ACPI issue.
tricky to give definite advice, but it usually boils down to adding a particular option to the kernel boot command (grub), sth like "acpi=vendor" maybe...

Ok, I start xev and move the cursor on the icon and then click the mute button (Fn+F10) on the keyboard. The only (new) output from xev is
and nothing else. I assume the FocusOut event comes from the sound icon that gets displayed because of the mute/unmute.

Sorry, I made a video and linked it in the first post but I will try to describe it better: In the video, I open terminals with journalctl, dmesg, xev and evtest and then click the mute button. Then, the mute icon appears and flickers (sound also makes some noise). It appears to be pressed many times per second for multiple seconds (while I pressed only once of course). I often cannot use any other key after this happens (appear to be blocked), mouse works fine however.
The other relevant log I think is `evtest /dev/input/event3`. There, the reaction to be pressing the button is a single
dmesg -w, journalctl -f and the xorg log do not output anything when I press the button.

Edit: Basically the same happens for F11 and F12 (audio increase/decrease). I can only do this with each button once, then they don't do anything anymore (until reboot).

What I concluded was that the kernel apparently correctly gets just one mute key signal but somehow the system receives hundreds of key presses at the end and I have no idea where to continue.

I will try some acpi kernel commandline options when I have access to the notebook on Monday again.

Hello,

I tried multiple acpi commandline options today. With there was no change in the behaviour. With one of the volume keys just did nothing (since acpi was (partially) disabled). So that seems not to help.

A friend also suggested to use evtest on (all in separate terminal windows) and there were no additional outputs in the other events (only the single key message in event3).

Edit: If you have further ideas or can think of helpful logs, I would be happy of course. If you have no idea however, it's no problem - these functions keys are not the most important feature

au contraire, that's an important troubleshooting step:
disabling acpi makes the symptoms go away.

i would suggest you to continue doing web searches...
actually nevermind, i did it for you:
https://askubuntu.com/questions/1048...at-key-presses

Thanks a lot! I don't see why I did not find the askubuntu entry you linked before... The problem seems to be the same,
and the solution here works: