I have bought a HP Pavilion Power 15-cb006ng and installed Linux Mint KDE on it. However, shortly after I started using it, it wouldn't shut down properly anymore. The first time it happened, I could get it down using "Alt+F7", but at some point that stopped working. The only solution left to me right now is the hard shut down, which is of course not a good way. This is what I see upon every shutdown:
The original cause of this issue remains unknown, however there is a fix:
Try out older versions of kernels until one works. The easiest way is to use the Ubuntu Kernel Upgrade Utility and then select to boot with the older kernel in GRUB. Once the desired kernel is found, uninstall all newer ones so that the working one becomes the default.
In the meantime, while the PC is not able to shutdown properly, use REISUB to at least achieve a somewhat gentle shutdown/restart.