Brightness keys not working and volume keys responds very slow

Question

I am running Ubuntu 17.04 on a Dell XPS 15 (9560) and it's been working well for over a month. A few days ago I suddenly started having issues with the Fn-shortcuts for brightness and volume.

Brightness keys do not work at all however I can still adjust brightness with the slider in the Brightness & Lock settings

Volume up, down and mute work, but it takes about 30 seconds from when the button is pressed to when the volume is actually changed. I also don't get any OSD notification about the volume change.

Using xev I could see that the media keys trigger XF86AudioRaiseVolume etc immediately on keypress. The brightness buttons do not show up in the xev logs at all but this might be normal even if they work.

Edit:

I'm getting suspicious of notify-osd as I'm not getting any notifications and running for example notify-send Testing does nothing but time-out after 50 seconds

Answer 1

This issue appears to be specific to Unity. It happened to me after upgrading to Ubuntu 17.10, and it even occurs with brand new accounts, meaning it's not some leftover configuration cruft. Gnome and KDE are unaffected. A workaround would be to switch to a different desktop environment.