How do I disable HDR? - eviltoast

So today I clicked ‘enable HDR’ on one of my monitors and something broke. The whole system froze up and the HDR monitor went black. If I reboot it freezes right after I login.

If I unplug that monitor or start in X11 instead of Wayland then everything is fine. Plugging the HDR monitor in while I’m logged into a Wayland session also freezes everything.

How can I disable the HDR setting? The monitor doesn’t show in System Settings whilst its unplugged so I’m hoping theirs some way to fix it on the CLI. The only place I’ve found HDR referenced is .config/kwinoutputconfig.json. I set HDR to false but after reboot it’s set to true again. I also tried deleting .config/kwinrc and .local/share/kscreen but no luck.

I’m fine with just resetting all Display settings if that’s required.

----- UPDATE ------

Bug report filed here: https://bugs.kde.org/show_bug.cgi?id=485403

Fixed by

  • Ctrl + Alt + F3 to go into terminal
  • Set HighDynamicRange and WideColorGamut to false in ~/.config/kwinoutputconfig.json
  • Execute plasmashell --replace
  • Reboot, Login, Reattach HDR Monitor

------ UPDATE ------

After updating and trying again today the steps above no longer worked. You still need to change ~/.config/kwinoutputconfig.json but plasmashell --replace no longer works for me.

Running killall kwin_wayland also just bumps me from my terminal back into the desktop. kwin can’t be running when you change that file or it will be overridden.

I booted into a separate Linux Live USB and change the files that way.

Thank you everyone for your help 🎉

  • Russ@bitforged.spaceEnglish
    1·
    7 months ago

    Since Plasma 6. Not sure about HDR wallpapers (never even heard of an “HDR Wallpaper”, so I’ve not looked into support for it), it should work with fullscreen videos though, and Steam games work if you run it through a nested gamescope session with a special HDR Vulkan layer installed.

    • Possibly linux@lemmy.zipEnglish
      2·
      7 months ago

      I assume it will work for a live system? When Fedora 40 eventually comes out I’ll give it a try. I can’t stand to daily drive plasma unfortunately. (Gnome works better for me)

      Maybe if it works well I’ll run plasma on a media machine.

      • Russ@bitforged.spaceEnglish
        1·
        7 months ago

        It should, yep! It’ll be in the Display Configuration if Plasma is properly detecting an HDR display.