SUMMARY Compositor slows down to ~1fps after changing any of the compositor settings. It can also be triggered by running `kwin --replace`. The only way I found of fixing this is to log out and back in. STEPS TO REPRODUCE 1. Log in to KDE. The compositor runs smoothly 2. Change compositor settings or restart kwin with `kwin --replace`. 3. Compositor now runs extremely slowly, around 1 fps. SOFTWARE/OS VERSIONS Windows: macOS: Linux/KDE Plasma: Ubuntu 21.04 (available in About System) KDE Plasma Version: 5.21.4 KDE Frameworks Version: 5.80.0 Qt Version: 5.12.2 ADDITIONAL INFORMATION Video demonstrating the issue: https://photos.app.goo.gl/373CiNmyF4MGjUZU6 There is no significant CPU or GPU utilization when the problem is triggered. The only way I found to make the desktop usable again without logging out is to change the compositor engine to XRender. kwin --replace prints the following: pmitas@pmitas-ThinkPad-T490 ~ kwin --replace & [1] 54579 ⚙ pmitas@pmitas-ThinkPad-T490 ~ kwin_xkbcommon: XKB: /usr/share/X11/locale/en_US.UTF-8/Compose:5079:46: this compose sequence is a duplicate of another; skipping line kwin_xkbcommon: XKB: /usr/share/X11/locale/en_US.UTF-8/Compose:5081:48: this compose sequence is a duplicate of another; skipping line kwin_xkbcommon: XKB: /usr/share/X11/locale/en_US.UTF-8/Compose:5083:48: this compose sequence is a duplicate of another; skipping line kwin_xkbcommon: XKB: /usr/share/X11/locale/en_US.UTF-8/Compose:5087:47: this compose sequence is a duplicate of another; skipping line kwin_xkbcommon: XKB: /usr/share/X11/locale/en_US.UTF-8/Compose:5089:46: this compose sequence is a duplicate of another; skipping line kwin_xkbcommon: XKB: /usr/share/X11/locale/en_US.UTF-8/Compose:5097:48: this compose sequence is a duplicate of another; skipping line kwin_xkbcommon: XKB: /usr/share/X11/locale/en_US.UTF-8/Compose:5101:46: this compose sequence is a duplicate of another; skipping line kwin_xkbcommon: XKB: /usr/share/X11/locale/en_US.UTF-8/Compose:5103:46: this compose sequence is a duplicate of another; skipping line kwin_xkbcommon: XKB: /usr/share/X11/locale/en_US.UTF-8/Compose:5107:45: this compose sequence is a duplicate of another; skipping line kwin_xkbcommon: XKB: /usr/share/X11/locale/en_US.UTF-8/Compose:5110:46: this compose sequence is a duplicate of another; skipping line ⚙ pmitas@pmitas-ThinkPad-T490 ~ OpenGL vendor string: Intel OpenGL renderer string: Mesa Intel(R) UHD Graphics 620 (WHL GT2) OpenGL version string: 4.6 (Compatibility Profile) Mesa 21.0.3 OpenGL shading language version string: 4.60 Driver: Intel GPU class: Unknown OpenGL version: 4.6 GLSL version: 4.60 Mesa version: 21.0.3 X server version: 1.20.11 Linux kernel version: 5.11 Requires strict binding: yes GLSL shaders: yes Texture NPOT support: yes Virtual Machine: no kwin_core: XCB error: 10 (BadAccess), sequence: 3883, resource id: 1998, major code: 142 (Composite), minor code: 2 (RedirectSubwindows)
I can reproduce this exactly as reported, here is my relevant part of the reporter's log: OpenGL vendor string: Intel Open Source Technology Center OpenGL renderer string: Mesa DRI Intel(R) HD Graphics 4600 (HSW GT2) OpenGL version string: 4.5 (Core Profile) Mesa 21.3.3 OpenGL shading language version string: 4.50 Driver: Intel GPU class: Haswell OpenGL version: 4.5 GLSL version: 4.50 Mesa version: 21.3.3 X server version: 1.20.13 Linux kernel version: 5.15 Requires strict binding: yes GLSL shaders: yes Texture NPOT support: yes Virtual Machine: no kwin_core: XCB error: 10 (BadAccess), sequence: 6512, resource id: 408, major code: 142 (Composite), minor code: 2 (RedirectSubwindows)
I am facing exactly the same issue. * System information: Operating System: Kubuntu 21.10 KDE Plasma Version: 5.23.5 KDE Frameworks Version: 5.90.0 Qt Version: 5.15.2 Kernel Version: 5.13.0-25-generic (64-bit) Graphics Platform: X11 Processors: 16 × Intel® Core™ i7-10700K CPU @ 3.80GHz Memory: 15,5 GiB of RAM Graphics Processor: Mesa Intel® UHD Graphics 630 * Relevant log: void@i7:~$ kwin --replace & [1] 8638 void@i7:~$ Warning: Setting a new default format with a different version or profile after the global shared context is created may cause issues with context sharing. kwin_xkbcommon: XKB: /usr/share/X11/locale/en_US.UTF-8/Compose:5089:46: this compose sequence is a duplicate of another; skipping line kwin_xkbcommon: XKB: /usr/share/X11/locale/en_US.UTF-8/Compose:5091:48: this compose sequence is a duplicate of another; skipping line kwin_xkbcommon: XKB: /usr/share/X11/locale/en_US.UTF-8/Compose:5093:48: this compose sequence is a duplicate of another; skipping line kwin_xkbcommon: XKB: /usr/share/X11/locale/en_US.UTF-8/Compose:5097:47: this compose sequence is a duplicate of another; skipping line kwin_xkbcommon: XKB: /usr/share/X11/locale/en_US.UTF-8/Compose:5099:46: this compose sequence is a duplicate of another; skipping line kwin_xkbcommon: XKB: /usr/share/X11/locale/en_US.UTF-8/Compose:5107:48: this compose sequence is a duplicate of another; skipping line kwin_xkbcommon: XKB: /usr/share/X11/locale/en_US.UTF-8/Compose:5111:46: this compose sequence is a duplicate of another; skipping line kwin_xkbcommon: XKB: /usr/share/X11/locale/en_US.UTF-8/Compose:5113:46: this compose sequence is a duplicate of another; skipping line kwin_xkbcommon: XKB: /usr/share/X11/locale/en_US.UTF-8/Compose:5117:45: this compose sequence is a duplicate of another; skipping line kwin_xkbcommon: XKB: /usr/share/X11/locale/en_US.UTF-8/Compose:5120:46: this compose sequence is a duplicate of another; skipping line OpenGL vendor string: Intel OpenGL renderer string: Mesa Intel(R) UHD Graphics 630 (CML GT2) OpenGL version string: 4.6 (Compatibility Profile) Mesa 21.2.2 OpenGL shading language version string: 4.60 Driver: Intel GPU class: Comet Lake OpenGL version: 4.6 GLSL version: 4.60 Mesa version: 21.2.2 X server version: 1.20.13 Linux kernel version: 5.13 Requires strict binding: yes GLSL shaders: yes Texture NPOT support: yes Virtual Machine: no kwin_core: XCB error: 10 (BadAccess), sequence: 2129, resource id: 1901, major code: 142 (Composite), minor code: 2 (RedirectSubwindows)
I am also facing the same issue, and I would say it is quite severe. Anything that tries to do something with the compositor will cause the problem. Even running an emulator like PPSSPP, and then closing it will cause the issue. This problem makes kwin and thus the whole plasma desktop essentially unusable for most use cases.
*** Bug 433664 has been marked as a duplicate of this bug. ***
*** Bug 445673 has been marked as a duplicate of this bug. ***
*** Bug 451125 has been marked as a duplicate of this bug. ***
I had the same problem. Figured out it only happened when one of my monitors (34 inch 2k) was connected (using Thunderbolt). When it's just my laptop screen or my 1080p HDMI screen everything was fine. Couldn't replicate it on a different user so I gathered it had to be config related. So, deleting monitor configurations fixed it: rm -rf ~/.local/share/kscreen Hope this helps someone :)
*** Bug 454843 has been marked as a duplicate of this bug. ***
(In reply to Opal from comment #7) > I had the same problem. Figured out it only happened when one of my monitors > (34 inch 2k) was connected (using Thunderbolt). When it's just my laptop > screen or my 1080p HDMI screen everything was fine. Couldn't replicate it on > a different user so I gathered it had to be config related. > So, deleting monitor configurations fixed it: > rm -rf ~/.local/share/kscreen > Hope this helps someone :) Sadly, that didn't actually solve it as it kept coming back, but I've found the setting that does it, at least for me: I have my 1080p laptop screen on the left of my 2k monitor. By default, the laptop monitor in aligned to the top of the 2k one, if I change that to the middle or bottom position and restart KWin, this replicates the issue. And vice versa reverting that change and restarting KWin solves it. A couple more things: 1. I can also replicate this with my external 1080p monitor instead of the laptop one. 2. I've replicated this both with a dual monitor and a triple monitor setup, however it only happens when the realigned 1080p monitor is on the left, changing the alignment for the screen on the right doesn't replicate this issue. I'll attach a screenshot to demonstrate this setting. Curious if others experiencing this have the same cause as me?
Created attachment 149614 [details] Display configuration that replicates this bug
Another solution is to use the environment variable KWIN_X11_REFRESH_RATE and set your own refresh rate, which also solves the issue (but forces you to choose the refresh rate and it won't adapt dynamically). As other pointed in a different thread, the issue seems to happen if the top-left corner of the whole desktop (the minimal rectangle which encloses/contains the screen sub-rectangles) doesn't correspond to any screen. What I mean is: if you set a screen at the top left, you are good. But if you move it slightly down or put another at the right and upper, it will fail. Maybe the code needs a default screen to check some properties, and tries to fetch the top-left one (probably the 0,0 coordinate?) So when nothing is there it simply fails and sets 1fps as a result?
Created attachment 151747 [details] Screen Configuration - my setup could not reproduce the reported issue I could not reproduce the issue on my setup. I did run "kwin_x11 --replace" since I don't use wayland, but the behaviour was the same as before. The only noted difference is when I try to record my screen using OBS (flatpak version), then it will add a black square around the pointer. I attached a screenshot of my settings, if I can provide more info to help I would need guidance in what info and how to get that. Hope it helps!
For me this used to reproduce every time, now it cannot reproduce anymore. Up to date Debian Unstable.
Thanks for the info, folks. What about you, Piotr?
For me, the issue still appears. If I have my 1080p monitor connected to my laptop, changing essentially anything related to kwin, like window decorations, everything slows down. Even when running a Game (which I guess disables and then re-enables the compositing) will then make everything sluggish. If I have no monitor connected, the issue cannot be reproduced. I am on Plasma 5.26.5, with NVIDIA proprietary drivers (although I believe this does not matter, as also with my integrated Intel GPU I have the same issue).