KDE @lemmy.kde.social ByteBovine @lemmy.ml 7mo ago

How do I disable HDR?

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 🎉

20 comments

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.
- The monitor does not display with kscreen-doctor -o as it's disconnected.
  
  I will create a bug report.
  
  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.
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
- This worked 👍 Thank you I also filed a bug report https://bugs.kde.org/show_bug.cgi?id=485403
Not an answer, but maybe the KDE folks should add "and may seriously break things" to the "is experimental" warning next to HDR :D
- Almost every output setting "may seriously break things" in my experience. Display drivers are sadly quite fragile
- This is why GNOME hasn't implemented it yet, they want to wait until it's perfect and not experimental before adding the feature.
Wait, since when does KDE support HDR? Can you have HDR wallpapers?
- 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.
  
  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.
Can’t you turn it off on the monitor?
- 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.
  
  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.
  
  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)
  
  Many monitors allow you to turn off HDR, they just claim they don't support it to the computer when you do that

20 comments