SUMMARY Animations move too fast under Nvidia Optimus. Most noticeable is the spinner on the Breeze login screen but any other spinners or similar types of animations move way faster under Optimus than they do normally. STEPS TO REPRODUCE 1. Acquire Optimus laptop, and configure PRIME offloading (I used the Debian wiki directions, use your distro of choice) 2. Load up Plasma 3. Observe things spinning too fast SOFTWARE/OS VERSIONS Debian Buster, Plasma 4.14.5, Frameworks 4.54.0, Qt 5.11.3 ADDITIONAL INFORMATION I'm not sure what component this was so please fix it if I'm totally off. I'm not sure what's causing it so I went as generic as possible.
Please run QSG_INFO=1 plasmashell --replace and attach the log Also output of "xrandr -q"
Created attachment 118028 [details] QSG_INFO=1 plasmashell --replace
Created attachment 118029 [details] xrandr -q
Information was provided; changing status for inspection.
This bug must be a high priority. kde: 5.15.5 qt: 5.12.3 "top" shows that "plasmashell" is using 100% of cpu while copying. I was copying files using Delphin to a share drive (a bit slow) and that spinner makes my computer hot for no reason. it is also annoying while starting any programm: the icon spins way to fast An obvious workaround is to disable it in: Notification Settings -> Information -> "Track file transfers and other jobs".
Ok, I think I managed to find the root of the problem It is a documented problem: https://doc.qt.io/qt-5/qtquick-visualcanvas-scenegraph.html "The threaded and windows render loops rely on the OpenGL implementation for throttling by requesting a swap interval of 1. Some graphics drivers allow users to override this setting and turn it off, ignoring Qt's request. Without blocking in the swap buffers operation (or elsewhere), the render loop will run animations too fast and spin the CPU at 100%. If a system is known to be unable to provide vsync-based throttling, use the basic render loop instead by setting QSG_RENDER_LOOP=basic in the environment" I have managed to fix it by running: QSG_RENDER_LOOP=basic plasmashell --replace
You can run "kcmshell5 qtquicksettings" to find a permanent config option for the render loop that will affect most apps
David, do you think this is the same issue/root cause as Bug 419421?
*** This bug has been marked as a duplicate of bug 390693 ***