Created attachment 189784 [details] Brush outline lag under X11 / Xwayland SUMMARY Krita 6.0 Brush outline lags a lot under X11 (Xwayland), the issue does not appear under 5.3 Currently two workarounds: 1) `vblank_mode=0` to force disable vsync 2) `QT_QPA_PLATFORM=wayland` to launch with native wayland mode. SOFTWARE/OS VERSIONS Operating System: Debian GNU/Linux 13 KDE Plasma Version: 6.5.4 KDE Frameworks Version: 6.20.0 Qt Version: 6.9.2 Kernel Version: 6.18.9+deb14-amd64 (64-bit) Graphics Platform: Wayland Graphics Processor : Intel UHD 770
Created attachment 189785 [details] disable vsync / native wayland mode without brush outline lag
Hi, Protoniv! Could you please tell, how many displays you have? Do they have the same framerate?
Just a side note: The bug might be related to bug 515571, which has the same effects, but is also related to a multi-monitor setup.
Might also be related: https://krita-artists.org/t/tested-v5-3-0-prealpha-6f434a9-ui-is-unbearably-slow/153549/8 And this: https://bugs.kde.org/show_bug.cgi?id=515820
(In reply to Dmitry Kazakov from comment #2) > Hi, Protoniv! > > Could you please tell, how many displays you have? Do they have the same > framerate? Hi, Dmitry! Have tested on 2 PCs, each with one monitor only: 1) 1920x1080, 60hz, single monitor, AMD radeon 780M, Mesa driver 2) 1920x1200, 60hz, single monitor, Intel igpu UHD770, Mesa driver The lag only appears under **krita 6.0 + X11 (Xwayland)** combo, does not happened to me with krita 5.3, or 6.0+Wayland Related krita-artist post: https://krita-artists.org/t/krita-5-3-6-0-beta-1-released/165015/57
Hi, Protoniv! What compositor do you use KWin or something else? PS: I can reproduce the issue on KWin, and I'm just gathering info for the proper fix
(In reply to Dmitry Kazakov from comment #6) > Hi, Protoniv! > > What compositor do you use KWin or something else? > Hi, Dmitry! I use KWin on all tested device.
Git commit b9be7b8b2e0dde06897c371520f6be3561dbdf61 by Dmitry Kazakov. Committed on 23/02/2026 at 12:27. Pushed by dkazakov into branch 'transition.now/qt6'. [qt][xcb] Implement QT_GLX_SWAP_INTERVAL_SYNC_WORKAROUND Related: bug 515571 M +1 -1 ext_qt/CMakeLists.txt https://invent.kde.org/packaging/krita-deps-management/-/commit/b9be7b8b2e0dde06897c371520f6be3561dbdf61
Git commit bd6975bd3843faa42347744ac33f1bc1ab453551 by Dmitry Kazakov. Committed on 23/02/2026 at 22:05. Pushed by dkazakov into branch 'master'. Implement a switch between EGL and GLX API on X11/XWayland This is an alternative version of the workaround for the GLX bug in Qt6. It allows the user to switch the openGL provider API from GLX to EGL, hence avoid this bug. This might be necessary for Krita builds provided by Linux distributions. M +9 -1 krita/main.cc M +8 -0 libs/ui/CMakeLists.txt M +35 -0 libs/ui/dialogs/kis_dlg_preferences.cc M +89 -78 libs/ui/forms/wdgdisplaysettings.ui M +19 -0 libs/ui/kis_config.cc M +4 -0 libs/ui/kis_config.h M +17 -0 libs/ui/opengl/KisOpenGLModeProber.cpp M +5 -0 libs/ui/opengl/KisOpenGLModeProber.h M +6 -0 libs/ui/opengl/kis_opengl.cpp M +7 -0 libs/ui/opengl/kis_opengl.h https://invent.kde.org/graphics/krita/-/commit/bd6975bd3843faa42347744ac33f1bc1ab453551
A possibly relevant merge request was started @ https://invent.kde.org/graphics/krita/-/merge_requests/2671
Git commit 70c4ccf8fa63f8ec4d0a7a5b938525faf6485048 by Dmitry Kazakov. Committed on 04/03/2026 at 07:48. Pushed by dkazakov into branch 'krita/6.0'. Implement a switch between EGL and GLX API on X11/XWayland This is an alternative version of the workaround for the GLX bug in Qt6. It allows the user to switch the openGL provider API from GLX to EGL, hence avoid this bug. This might be necessary for Krita builds provided by Linux distributions. M +9 -1 krita/main.cc M +8 -0 libs/ui/CMakeLists.txt M +35 -0 libs/ui/dialogs/kis_dlg_preferences.cc M +89 -78 libs/ui/forms/wdgdisplaysettings.ui M +19 -0 libs/ui/kis_config.cc M +4 -0 libs/ui/kis_config.h M +17 -0 libs/ui/opengl/KisOpenGLModeProber.cpp M +5 -0 libs/ui/opengl/KisOpenGLModeProber.h M +6 -0 libs/ui/opengl/kis_opengl.cpp M +7 -0 libs/ui/opengl/kis_opengl.h https://invent.kde.org/graphics/krita/-/commit/70c4ccf8fa63f8ec4d0a7a5b938525faf6485048
Git commit cf2458569ffee175499fc9700521f5d1e9782220 by Dmitry Kazakov. Committed on 04/03/2026 at 14:17. Pushed by dkazakov into branch 'release/6.0.0'. Implement a switch between EGL and GLX API on X11/XWayland This is an alternative version of the workaround for the GLX bug in Qt6. It allows the user to switch the openGL provider API from GLX to EGL, hence avoid this bug. This might be necessary for Krita builds provided by Linux distributions. M +9 -1 krita/main.cc M +8 -0 libs/ui/CMakeLists.txt M +35 -0 libs/ui/dialogs/kis_dlg_preferences.cc M +89 -78 libs/ui/forms/wdgdisplaysettings.ui M +19 -0 libs/ui/kis_config.cc M +4 -0 libs/ui/kis_config.h M +17 -0 libs/ui/opengl/KisOpenGLModeProber.cpp M +5 -0 libs/ui/opengl/KisOpenGLModeProber.h M +6 -0 libs/ui/opengl/kis_opengl.cpp M +7 -0 libs/ui/opengl/kis_opengl.h https://invent.kde.org/graphics/krita/-/commit/cf2458569ffee175499fc9700521f5d1e9782220