It happens only on Wayland session and only in KDE. I've tested with Gnome + wayland and it works there just as good as in KDE X session. Start Blender and open up, lets say, File menu and move your mouse up and down within this menu. You'll see menu flickering.
I'll add some more info... First, here's a screen recording of the issue: https://drive.google.com/file/d/0B_iE50uqUIIba2kzUUdVRXdlcG8/view Also, for me it happens on both Wayland and X. Since Blender doesn't support Wayland (according to the Kwin debug console) it doesn't seem surprising to me. I've tried changing the compositing between OpenGL 3.1, OpenGL 2.0, and XRender and there was no difference. I've seen this happen once or twice before with a program running under Wine but I don't think it's happened with a native program before.
I should note that I am on Arch Linux with r600g Mesa drivers and xf86-video-ati.
ouch that looks horrible.
ok, just installed Blender and of course I don't get this flickering.
Hmmm... The only other program that I can remember having this problem is the Windows program I mentioned. I wrote a PlayOnLinux script some time ago for the program; it's called Crossword Compiler. It only acted up sometimes, and I can't remember when, but I think the problem showed up with normal usage... If you feel like trying it, you should be able to just install PlayOnLinux and click the "Install this program" button here: https://www.playonlinux.com/en/app-2697-Crossword_Compiler.html If I can be of any help with e.g. GDB let me know.
I can try, but I doubt I would trigger it. I rather think that our systems are different in some way which make it not happen on mine. The most obvious candidate is the GPU, as I'm on Intel. Some ideas: monitor dmesg for drm warnings, maybe run blender with MESA_DEBUG env variable (see https://www.mesa3d.org/envvars.html ). Maybe also run kwin with this variable. Given how it looks an OpenGL error somewhere in the stack might be the reason. Also you could add the support information for KWin (qdbus org.kde.KWin /KWin supportInformation). Maybe there's an effect playing into it which I don't have activated.
Created attachment 104747 [details] qdbus_output
(In reply to Matthew Trescott from comment #1) Wow, i actually have it better. In my case only menus flicker. And i'm also using r600g Mesa drivers, i have HD 5770. Also how did you record a video in wayland? MESA_DEBUG gave this: connect(2) call to /dev/shm/jack-1000/default/jack_0 failed (err=No such file or directory) attempt to connect to server failed Warning! Unable to find a multisample pixel format that supports exactly 4 samples. Substituting one that uses 0 samples. But it has nothing to do with OpenGL it seems.
I didn't record on Wayland; this happens for me on both Wayland (XWayland since Blender doesn't support Wayland) and X.Org. I just used SimpleScreenRecorder.
I've recorded a video with OpenGL option(the regular gave out black screen with only mouse pointer visible) in SimplesScreenRecorder. But in the video everything is smooth and no flickering is happening. At the same time i saw some critical bug. I don't know if KDE bug tracker is the right place to post. If i play video(smplayer/clean mpv): 1) video is separated from controls 2) if i grab the video with mouse pointer and move it until video finishes everything crashes, not even console(ALt+F1 etc) is available.
By the way, disabling compositing (Alt+Shift+F12) doesn't solve the problem—a driver bug then?
Tried in Openbox---looked slightly different but seems to be the same bug either with Blender or my drivers. Sorry for the inconvenience.
Found this bug report: https://developer.blender.org/T26240 Switching "Window Draw Method" to "Full" or "Triple Buffer" in Blender User Preferences ("System" tab) fixed the Problem for me. Don't forget to save user preferences though.
Sounds like not a bug in our software. Thanks for the update.
It appears Fedora didn't run wayland because when i've installed Gnome on Manjaro i had the same problem under Gnome wayland session. Switching "Window Draw Method" from "Triple Buffer" to "Full" solved a menu flickering problem lost a Blender feature. Not a big problem though comparing to this https://bugs.kde.org/show_bug.cgi?id=377942