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 🎉

  • RustmilianEnglish
    32•2 months ago

    kscreen-doctor -o
    Then adjust the below command accordingly :
    kscreen-doctor output.1.hdr.disable

    Make sure you go open a bug report.
    When you do, you can use hw-probe and run :
    sudo -E hw-probe -all -upload -dump-acpi -decode-acpi
    And use the given link in your BR.

    • @[email protected]OP
      2•2 months ago

      The monitor does not display with kscreen-doctor -o as it’s disconnected.

      I will create a bug report.

      • RustmilianEnglish
        3•2 months ago

        I see you got it fixed.
        When you run hw-prope make sure your offending monitor is connected. hw-prope will help identify the monitor by hardware ID which is used in various areas like kernel space and will help with identifying the exact model of the problem monitor hopefully allowing for devs to reproduce the bug in a lab environment.

          • RustmilianEnglish
            3•2 months ago

            Looking through the probe logs, and seeing that your monitor is using EISA bus and works fine without HDR, there doesn’t appear to be any issues on the Linux side of things. My guess is that they didn’t implement HDR on the monitors side exactly to spec and that’s where the problem resides. So, in this sense some monitor specific quirk fixup code is needed on the Linux side of things to get it working properly. If the devs ask any additional steps from you, be sure to do it and provide feedback.

          • RustmilianEnglish
            3•2 months ago

            Which one of these is the problem monitor? benq or gigabyte ?

            Edit : nvm, I see you already said Gigabyte.

  • @[email protected]English
    7•2 months ago

    Changing the output config file should work, as long as KWin isn’t running while you make the change (in which case the change will just be overridden)

    Edit: Also, please make a bug report about this for KWin. It’s probably not a KWin issue, but we can usually figure out where it’s coming from

  • UnfortunateShort
    5•2 months ago

    Not an answer, but maybe the KDE folks should add “and may seriously break things” to the “is experimental” warning next to HDR :D

    • @[email protected]English
      1•2 months ago

      Almost every output setting “may seriously break things” in my experience. Display drivers are sadly quite fragile

    • setVeryLoud(true);
      0•2 months ago

      This is why GNOME hasn’t implemented it yet, they want to wait until it’s perfect and not experimental before adding the feature.

    • @[email protected]English
      1•2 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 linuxEnglish
        2•2 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.

        • @[email protected]English
          1•2 months ago

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

    • @[email protected]
      1•2 months ago

      I don’t think that is something any HDR monitor can do, unfortunately. They just let you know it’s in HDR mode.

      Edit: I stand corrected.

      • @[email protected]
        5•2 months ago

        My monitor AW2432DWF does allow you to turn off HDR, although it is a relatively recent monitor and my first HDR one, so I don’t know how common that is.

      • @[email protected]
        4•2 months ago

        HDR for the most part, is a two way feature. must be enabled by driver/de as well as enabled on the monitor for it to in work, because its not always ideal to have local dimming enabled on monitor (one of the key components required for HDR)

      • @[email protected]English
        3•2 months ago

        Many monitors allow you to turn off HDR, they just claim they don’t support it to the computer when you do that