https://bugs.kde.org/show_bug.cgi?id=449519
--- Comment #5 from postix <pos...@posteo.eu> --- (In reply to Vlad Zahorodnii from comment #4) > any ideas why kwin uses a software rasterizer? I got a little bit further in investigating it: The issue did not come from any update from KWin (that's good!). However, it appeared since I have `correctly` installed the `guest additions`: First I have installed `gcc perl make`, which I had forgotten before, so before I actually had no additional Kernel module built / installed. Then via the VBox GUI I have mounted the guest addtions and ran `sudo /mnt/(...)/VBoxLinuxAddtions.sh` and finally rebooted. Now, before and after I did that, I saved the KWin support information and here's the diff: `diff kwin_supportInformation_without_linux_additions.txt kwin_supportInformation_with_linux_addtions.txt` ``` 63c63 < Atomic Mode Setting on GPU 0: true --- > Atomic Mode Setting on GPU 0: false 154c154 < Geometry: 0,0,1920x1080 --- > Geometry: 0,0,1280x800 156c156 < Refresh Rate: 59996 --- > Refresh Rate: 59987 ``` Apparently `Atomic Mode Setting on GPU 0` has changed due to the Linux guest addition installation, but I don't know how why it did that nor how I could control that and if that's the or a part of the root cause. Anything else I may check? Does this gives you a hint of what may be going wrong and why? -- You are receiving this mail because: You are watching all bug changes.