Screen brightness changes when switching power profiles

I’ve just installed Endeavour on a ThinkPad T14 Gen 4 (AMD 7840U, OLED display) and pretty much everything works OOTB but I’ve got this strange issue with the display and power profiles.

After a clean install of Endeavour w/ KDE Plasma, it seems changing the active power profile inversely affects the display’s brightness. In the performance profile the screen brightness works and looks as I’d expect, but switching to the balanced profile it starts to brighten the screen. Switching to power save it brightens it ever further to the point where the contrast looks cranked up and all the colors look blown out.

In my power management settings none of the plugged in/on battery/low power profiles touch the display brightness, and the brightness reported by the OS doesn’t actually change when this happens. I’ll have my brightness set to 25% on the performance profile and then I switch to power save, the whole screen gets like twice as bright yet it’s still 25% brightness.

There have been a few times when it hasn’t done this, after noticing the issue for the first time I decided to completely reinstall Endeavour and immediately after a completely clean install the issue did not occur until I went in to change some display settings, then it started happening and reverting the settings did not fix it. The last setting I changed before it started happening was HDR (because this model has the OLED screen).

Rebooting makes no difference and I’ve updated everything that fwupd will let me. Not sure what else to try from here.

It is probably related to hdr. When you have hdr on, the brightness is controlled differently for example the display brightness slider in the system tray should no longer do anything. The changing brightness with power profile thing is probably a bug and hdr in general is still pretty new and has some issues for some people.

You can use the sliders for sdr brightness and intensity under the hdr section in display settings to fiddle around with it, but I don’t think it will fix your power profile issue. I’ll see if someone has already reported the issue with power profiles.

Edit: I couldn’t find any issue reported about hdr and power profiles, so you should report it. Unfortunately I don’t have a laptop with a fancy display to test this out on. My desktop monitors have hdr, but it is a desktop so there are no power profiles in the first place.

Thanks for the reply. Part of my confusion was I didn’t know who exactly to report this to. Does this go to Wayland because HDR? Or power-profiles-daemon?

No it should go to KDE. Wayland is just a protocol. It is up to individual people to implement the protocol. KDE’s implementation is different than Gnome’s implementation which is different from Cosmic’s implementation so to speak. Therefore something is going wrong with the interaction between their implementation and the power profiles daemon. If they should determine that it is an upstream issue, they will make sure it gets to the right place.

I did some searching on KDE’s forum and found a related thread with a workaround to disable the feature for now. I left a reply there and I guess I’ll leave it at that for now since they seem to be aware of the issue already. Thanks again for your help!


Thank you for following up. I swear I forget they have a forum now.

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