Created attachment 152733 [details] photo of monitors SUMMARY Image produced by KWin on Wayland on nouveau output is distorted in kind of "interlaced way". See attached screenshot and photo of monitors. Note the mouse cursor/pointer is rendered OK. While background and windows are not. With Sway WM, it works flawlessly. The same with Wayfire. Plasma/X11 started kernel panicking (no Magic SysRq working) lately, before it was OK. KWin/Wayland worked for me several months ago with just a little bug: It appeared the same as now upon startup, but to correct the second output I had to do the following procedure: 1) Changing resolution to lower and then back to FullHD. 2) Move window from First screen to the second. 3) Voila! the output is corrected. The procedure no longer fixes the output. I have also tried attaching another monitor to another ouput of nouveau, the image there was distorted the same way. What I have tried and found the bug is not in: * Plasma/X11 works even with second monitor * Sway/Wayland & Wayfire/Wayland works even with second monitor * Plasma/Wayland with only internal display (possibly Intel output) works STEPS TO REPRODUCE 1. Have nvidia card with nouveau driver. 2. Start the "Plasma (Wayland)" through DM (SDDM). 3. Observer result. OBSERVED RESULT Distorted image produced on second and following outputs in kind of "interlaced way". See attachments. EXPECTED RESULT Correct image produced on all outputs. SOFTWARE/OS VERSIONS Linux/KDE Plasma: Arch Linux up-to-date Operating System: Arch Linux KDE Plasma Version: 5.25.5 KDE Frameworks Version: 5.99.0 Qt Version: 5.15.6+kde+r177 Kernel Version: 5.19.13-zen1-1-zen (64-bit) Graphics Platform: Wayland Processors: 8 × Intel® Core™ i7-2760QM CPU @ 2.40GHz Memory: 23,4 GiB of RAM Graphics Processor: Mesa Intel® HD Graphics 3000 Manufacturer: LENOVO Product Name: 4282CL7 System Version: ThinkPad W520 ADDITIONAL INFORMATION $ lsmod | grep "nouv\|i915" i915 3387392 63 drm_buddy 20480 1 i915 intel_gtt 28672 1 i915 nouveau 2904064 5 mxm_wmi 16384 1 nouveau drm_ttm_helper 16384 1 nouveau ttm 98304 3 drm_ttm_helper,i915,nouveau drm_display_helper 192512 2 i915,nouveau cec 90112 2 drm_display_helper,i915 wmi 40960 4 wmi_bmof,think_lmi,mxm_wmi,nouveau video 61440 3 thinkpad_acpi,i915,nouveau $ lspci | grep VGA 00:02.0 VGA compatible controller: Intel Corporation 2nd Generation Core Processor Family Integrated Graphics Controller (rev 09) 01:00.0 VGA compatible controller: NVIDIA Corporation GF108GLM [Quadro 1000M] (rev a1) $ xrandr --listmonitors Monitors: 2 0: +*XWAYLAND0 1920/340x1080/190+0+0 XWAYLAND0 1: +XWAYLAND1 1920/510x1080/290+1920+0 XWAYLAND1 $ xrandr --listproviders Providers: number : 0 Feel free to ask for more details. I would love to help with that.
Created attachment 152734 [details] software screenshot
Can you check whether the issue is gone after setting KWIN_DRM_USE_MODIFIERS=0 envvar?
(In reply to Vlad Zahorodnii from comment #2) > Can you check whether the issue is gone after setting > KWIN_DRM_USE_MODIFIERS=0 envvar? Unfortunately has no positive impact.
Other potentially related env variables. $ env | grep -E -i "QT|KDE|PLASMA|KWIN|WAYLAND|WL|NVI|NOU|X11" DESKTOP_SESSION=plasmawayland KDE_APPLICATIONS_AS_SCOPE=1 KDE_FULL_SESSION=true KDE_SESSION_UID=1000 KDE_SESSION_VERSION=5 KWIN_DRM_USE_MODIFIERS=0 PLASMA_USE_QT_SCALING=1 QT_AUTO_SCREEN_SCALE_FACTOR=0 QT_WAYLAND_FORCE_DPI=96 WAYLAND_DISPLAY=wayland-0 XDG_ACTIVATION_TOKEN=kwin-3 XDG_CONFIG_DIRS=/home/gary/.config/kdedefaults:/etc/xdg XDG_CURRENT_DESKTOP=KDE XDG_SESSION_DESKTOP=KDE XDG_SESSION_TYPE=wayland
Please attach the output of drm_info (https://github.com/ascent12/drm_info) Can you also try with KWIN_DRM_PREFER_COLOR_DEPTH=24?
(In reply to Zamundaaa from comment #5) > Please attach the output of drm_info (https://github.com/ascent12/drm_info) > Can you also try with KWIN_DRM_PREFER_COLOR_DEPTH=24? Even this has no positive impact.
Created attachment 152741 [details] drm_info output
Unfortunately no positive impact with: KDE Plasma Version: 5.26
The bug is present also in downgraded KWin 5.25.1 . 5.25.0 has black screen for me. And 5.24.5 needs further packages downgraded, which I haven't done. Are you sure it is the KWin package bug? Are there any logs that could help to fix the bug?
> Are you sure it is the KWin package bug? I think if Plasma/X11 causes a kernel panic, and downgrading KWin doesn't change anything, you're almost certainly looking at a kernel bug (or multiple).
Update: I'm back on Plasma/X11 since yesterday. So far it works right /knock knock/. Nevertheless I'm ready to help with Plasma/Wayland, once something is needed.
There's been significant improvements in the multi gpu handling in Plasma 6, so this is most likely fixed. In case you're still experiencing glitches, please reopen this