I'm on Arch Linux with Plasma 5.4.1. I have installed the game "Globonation 2", and I have enabled the full screen setting in this game. After this my display turned black and "no signal" showed up. My problem is this is now a persistent problem! I rebooted many times, sddm works fine, but as soon as I login my display turns black again, shows "no signal" and finally goes into stand by.

I have no idea what this game did, and I have no idea where to look. Only thing that works at the moment is tty2 and booting with nomodeset. Xorg log and dmesg show no apparent errors.

How does KDE/Plasma handle screen settings? Where are they saved and how can I reset my display settings?

Also, I have installed two new plasmoids, a network and system monitor. My plasmashell process is constantly consuming 100% of one of my CPU cores, and does not react to mouse clicks. Killing it and restarting plasmashell does not help. How can I remove those plasmoids if I can't remove them through the regular way? Are the panel settings saved in some config file?

Thanks alot for help, right now my Plasma desktop is totally broken and I would like to avoid to reinstall everything.

Nevermind regarding the black screen! There is a post a few posts below, "How do I reset my monitor settings", which had the answer to my problem

Apparently the game did set a resolution that my display did not support, and that resolution was saved in ~/.local/share/kscreen/

I deleted that folder and now everything works again, except for my plasmashell issue.

simonv wrote:I deleted that folder and now everything works again, except for my plasmashell issue.

The plasmoid configuration is in ~/.config/plasma-org.kde.plasma.desktop-appletsrc.

wolfi323 wrote:The plasmoid configuration is in ~/.config/plasma-org.kde.plasma.desktop-appletsrc.

Thanks alot! I was able to remove the allegedly problematic plasmoids, but my plasmashell is still consuming a full CPU core and is still totally unresponsive.

The plasmashell problems started when I first started this "Globonation 2" game. When I first started the game it was windowed and plasmashell immediately became unresponsive. I rebooted and after that plasmashell was still consuming a lot of CPU, so I suspected the plasmoids to be the cause, but it seems that stupid game must have started this all. Because after the first reboot I started this game again and went to options to turn on fullscreen, and that's when my screen went dark.

This is so annoying I wish I never installed that stupid game. How can it even break my system this bad