KDE Plasma 6 external monitor display freezes whilst gaming (SOLVED)

[Arceles]

Hi, I did not know where to put this but I still wanted to create a post so that anybody that faces the same issue can have  a solution.

On my laptop (Asus AMD Advantage ROG Strix G513QY_G513QY) I have the integrated GPU that comes with my processor and the dedicated GPU which is a 6800m.

On KDE Plasma 6 I was having the issue that the moment a game was being started the external display would completely freeze (NOTE, EXTERNAL DISPLAY CONNECTED BY USB-C HUB, NOT THE HDMI PORT). Originally I thought that this was because of some sort of incompatibility with proton but this was quickly ruled out in several other PCs that I have with both AMD and NVIDIA hardware. Pressing the super key would actually bring the KDE menu and the display would seemingly unfreeze, but when setting the focus back in the game again the display would freeze again.

The systems were everything has been working wonders are Desktops and in them I have arch running with no issues also with KDE.

The only clue that I had is that if I ran dmesg I would get several errors with

*ERROR* Failed to pin framebuffer with error -12

Then for whatever reason it occurred to me that there it was some sort of conflict between the iGPU and dGPU.

Then I followed a similar approach from https://discussion.fedoraproject.org/t/display-rendering-is-slow-on-plasma-6-on-an-external-monitor/114143/18 and decided to do the same but with my own Ids, that is:

            Add the following in /etc/environment
                KWIN_DRM_DEVICES="/dev/dri/by-path/pci-0000\:03\:00.0-card:/dev/dri/by-path/pci-0000\:08\:00.0-card"

            The above example is to indicate that the prioritised gpu to render the screen will be the one at the 0000:03:00.0 PCI adress
            (RX 6800M DGPU) and, in case that gpu is missing, it will use the one at 0000:08:00.0 which is the integrated GPU in the R9 5980HX CPU.
            To get these numbers please use lspci which will return the correct PCI paths which you’ll have to change in the environment variable.

Please note that lspci does only return one value with lspci | grep VGA (as mentioned in the post) therefore I listed all devices without the grep.

I rebooted and that was that, it solved the issue and now the screen does not freeze anymore.

Hope this helps anybody as it did for me (I looked for a solution for about 4 months :P but I simply could not put it into words to look for them into google)

 

Edited April 9 by Arceles

[Mindovermaster Global Moderator]

Thanks, Arceles. A friend of mine had this problem as well. I can now point him to this..

[Arceles]

  On 09/04/2025 at 04:30, Mindovermaster said:

Thanks, Arceles. A friend of mine had this problem as well. I can now point him to this..

Expand  

Plasma 6 was supposed to address some multigpu shennanigans like this, but I'm betting that for this particular case since lspci does not say VGA in the dedicated gpu Plasma 6 had this issue.

I normally do not game in this laptop (it is mostly used for photo and video editing on the go) that is why I also did not looked further into the issue.

Glad that it helps somebody, cheers!

[Mindovermaster Global Moderator]

Most newer laptops have HDMI, not VGA. Nothing except servers use VGA anymore.

Prolly because it is an old architecture, they never worried about it.

[Arceles]

It is more of (Video Graphics Adapter) thing that it is expecting to find I guess, but you are right, the port itself is well long gone.