Even after the fix mentioned in this bug report https://bugs.kde.org/show_bug.cgi?id=385924, I still have flickering issues with Kmail on Wayland in the following cases: 1.) Open fullscreen Kmail and move the mouse up and down in the menu e.g. in Files => flickering of the menu window 2.) Open fullscreen Kmail and then afterwards another fullscreen application e.g. Kate. Then either move the mouse e.g. into certain areas of the plasma panel or near the close button (not always the same), or just open in Kate e.g. the Files menu then you will see Kmail instead of Kate. => flickering and wrong application surface Plasma 5.11.3 KDE Frameworks 5.40 KDE Applications 17.11.80 Qt 5.10 beta 4 (compiled with 5.9.2) Arch Linux 4.14 Mesa-git on AMD GPU For reference I opened some time ago the bug https://bugs.kde.org/show_bug.cgi?id=385678, but I didn't get a response.
Please provide the output of: qdbus org.kde.KWin /KWin supportInformation I will probably ask for more information once I have a better idea what could cause this. In all the testing I did on my system I was no longer able to reproduce it. So I need to try figuring out where the difference is. Just to make sure: with fullscreen you mean maximized, right?
Please find below the requested information. If you need anything else, let me know! Yes, by fullscreen I meant maximized window, sorry. This triggers the flickering more obvious. $ qdbus org.kde.KWin /KWin supportInformation KWin-Unterstützungsinformationen: Benutzen Sie die folgenden Informationen, wenn Sie nach Unterstützung fragen, z. B. auf http://forum.kde.org. Sie enthalten Informationen über die momentan laufende Instanz, welche Optionen verwendet werden, welcher OpenGL-Treiber verwendet wird und welche Effekte laufen. Bitte geben Sie die unten stehenden Informationen bei einem Pastebin-Dienst wie http://paste.kde.org ein, anstatt sie direkt in die Hilfediskussionen zu schreiben. ========================== Version ======= KWin version: 5.11.3 Qt Version: 5.10.0 Qt compile version: 5.10.0 XCB compile version: 1.12 Operation Mode: Xwayland Build Options ============= KWIN_BUILD_DECORATIONS: yes KWIN_BUILD_TABBOX: yes KWIN_BUILD_ACTIVITIES: yes HAVE_INPUT: yes HAVE_DRM: yes HAVE_GBM: yes HAVE_X11_XCB: yes HAVE_EPOXY_GLX: yes HAVE_WAYLAND_EGL: yes X11 === Vendor: The X.Org Foundation Vendor Release: 11905000 Protocol Version/Revision: 11/0 SHAPE: yes; Version: 0x11 RANDR: yes; Version: 0x14 DAMAGE: yes; Version: 0x11 Composite: yes; Version: 0x4 RENDER: yes; Version: 0xb XFIXES: yes; Version: 0x50 SYNC: yes; Version: 0x31 GLX: yes; Version: 0x0 Decoration ========== Plugin: org.kde.breeze Theme: Blur: 0 onAllDesktopsAvailable: false alphaChannelSupported: true closeOnDoubleClickOnMenu: true decorationButtonsLeft: 0, 2 decorationButtonsRight: 3, 4, 5 borderSize: 3 gridUnit: 12 font: Noto Sans,10,-1,5,50,0,0,0,0,0,Regular smallSpacing: 3 largeSpacing: 12 Options ======= focusPolicy: 0 nextFocusPrefersMouse: false clickRaise: true autoRaise: false autoRaiseInterval: 0 delayFocusInterval: 0 shadeHover: false shadeHoverInterval: 250 separateScreenFocus: false placement: 4 focusPolicyIsReasonable: true borderSnapZone: 10 windowSnapZone: 10 centerSnapZone: 0 snapOnlyWhenOverlapping: false rollOverDesktops: true focusStealingPreventionLevel: 1 legacyFullscreenSupport: false operationTitlebarDblClick: 5000 operationMaxButtonLeftClick: 5000 operationMaxButtonMiddleClick: 5015 operationMaxButtonRightClick: 5014 commandActiveTitlebar1: 0 commandActiveTitlebar2: 30 commandActiveTitlebar3: 2 commandInactiveTitlebar1: 4 commandInactiveTitlebar2: 30 commandInactiveTitlebar3: 2 commandWindow1: 7 commandWindow2: 8 commandWindow3: 8 commandWindowWheel: 31 commandAll1: 10 commandAll2: 3 commandAll3: 14 keyCmdAllModKey: 16777251 showGeometryTip: false condensedTitle: false electricBorderMaximize: true electricBorderTiling: true electricBorderCornerRatio: 0.25 borderlessMaximizedWindows: false killPingTimeout: 5000 hideUtilityWindowsForInactive: true inactiveTabsSkipTaskbar: false autogroupSimilarWindows: false autogroupInForeground: true compositingMode: 1 useCompositing: true compositingInitialized: true hiddenPreviews: 1 glSmoothScale: 2 xrenderSmoothScale: false maxFpsInterval: 16666666 refreshRate: 0 vBlankTime: 6000000 glStrictBinding: false glStrictBindingFollowsDriver: true glCoreProfile: true glPreferBufferSwap: 101 glPlatformInterface: 2 windowsBlockCompositing: true Screen Edges ============ desktopSwitching: false desktopSwitchingMovingClients: false cursorPushBackDistance: 1x1 timeThreshold: 150 reActivateThreshold: 350 actionTopLeft: 0 actionTop: 0 actionTopRight: 0 actionRight: 0 actionBottomRight: 1 actionBottom: 0 actionBottomLeft: 0 actionLeft: 0 Screens ======= Multi-Head: no Active screen follows mouse: no Number of Screens: 1 Screen 0: --------- Name: SAM DP-3-U28D590 Geometry: 0,0,3840x2160 Refresh Rate: 59.997 Compositing =========== Compositing is active Compositing Type: OpenGL OpenGL vendor string: X.Org OpenGL renderer string: AMD Radeon (TM) RX 480 Graphics (POLARIS10 / DRM 3.23.0 / 4.15.0-rc1-g516fb7f2e73d, LLVM 6.0.0) OpenGL version string: 4.5 (Core Profile) Mesa 17.4.0-devel (git-b6b4b2c6d8) OpenGL platform interface: EGL OpenGL shading language version string: 4.50 Driver: Unknown GPU class: Unknown OpenGL version: 4.5 GLSL version: 4.50 Mesa version: 17.4 Linux kernel version: 4.15 Direct rendering: Requires strict binding: no GLSL shaders: yes Texture NPOT support: yes Virtual Machine: no OpenGL 2 Shaders are used Painting blocks for vertical retrace: no Loaded Effects: --------------- kwin4_effect_dialogparent kwin4_effect_fade kwin4_effect_frozenapp kwin4_effect_login kwin4_effect_logout kwin4_effect_maximize kwin4_effect_morphingpopups kwin4_effect_translucency kwin4_effect_windowaperture slidingpopups slide screenshot minimizeanimation desktopgrid colorpicker presentwindows highlightwindow blur contrast startupfeedback screenedge kscreen Currently Active Effects: ------------------------- blur contrast Effect Settings: ---------------- kwin4_effect_dialogparent: kwin4_effect_fade: kwin4_effect_frozenapp: kwin4_effect_login: kwin4_effect_logout: kwin4_effect_maximize: kwin4_effect_morphingpopups: kwin4_effect_translucency: kwin4_effect_windowaperture: slidingpopups: fadeInTime: 75 fadeOutTime: 125 slide: screenshot: minimizeanimation: desktopgrid: zoomDuration: 150 border: 10 desktopNameAlignment: 0 layoutMode: 0 customLayoutRows: 2 usePresentWindows: true colorpicker: presentwindows: layoutMode: 0 showCaptions: true showIcons: true doNotCloseWindows: false ignoreMinimized: false accuracy: 20 fillGaps: true fadeDuration: 75 showPanel: false leftButtonWindow: 1 rightButtonWindow: 2 middleButtonWindow: 0 leftButtonDesktop: 2 middleButtonDesktop: 0 rightButtonDesktop: 0 highlightwindow: blur: blurRadius: 12 cacheTexture: true contrast: startupfeedback: type: 1 screenedge: kscreen: $ kmail Using Wayland-EGL Pass a valid window to KWallet::Wallet::openWallet(). Error loading text-to-speech plug-in "speechd" WebEngine compiled with X11 support, however qpa backend is not xcb. This may fail. [1127/200750.064690:WARNING:stack_trace_posix.cc(648)] Failed to open file: /home/rainer/#613789 (deleted) Error: Datei oder Verzeichnis nicht gefunden Using the 'wl-shell' shell integration
I see a difference to my system: kmail is using wl_shell, while on my system it is already xdg_shell.
What do I need for the new xdg_shell support? I did compile kwin and KDE frameworks from git. Is this enough already?
Yeah, it is in git master
Oh yes, the new xdg_shell works. I can run libreoffice and Virt-Manager including keyboard input in a VM on Wayland, awesome!!! :-) Back to the topic, unfortunately kmail is still the application triggering the flickering in a maximized window, if another application is on top, most obvious when scrolling in another application like in Kate in the Files menu. $ kmail Using Wayland-EGL Pass a valid window to KWallet::Wallet::openWallet(). Error loading text-to-speech plug-in "speechd" WebEngine compiled with X11 support, however qpa backend is not xcb. This may fail. [1128/072341.092714:WARNING:stack_trace_posix.cc(648)] Failed to open file: /home/rainer/#148529 (deleted) Error: Datei oder Verzeichnis nicht gefunden Using the 'xdg-shell-v6' shell integration $ qdbus org.kde.KWin /KWin supportInformation KWin Support Information: The following information should be used when requesting support on e.g. http://forum.kde.org. It provides information about the currently running instance, which options are used, what OpenGL driver and which effects are running. Please post the information provided underneath this introductory text to a paste bin service like http://paste.kde.org instead of pasting into support threads. ========================== Version ======= KWin version: 5.11.90 Qt Version: 5.10.0 Qt compile version: 5.10.0 XCB compile version: 1.12 Operation Mode: Xwayland Build Options ============= KWIN_BUILD_DECORATIONS: yes KWIN_BUILD_TABBOX: yes KWIN_BUILD_ACTIVITIES: yes HAVE_INPUT: yes HAVE_DRM: yes HAVE_GBM: yes HAVE_X11_XCB: yes HAVE_EPOXY_GLX: yes HAVE_WAYLAND_EGL: yes X11 === Vendor: The X.Org Foundation Vendor Release: 11905000 Protocol Version/Revision: 11/0 SHAPE: yes; Version: 0x11 RANDR: yes; Version: 0x14 DAMAGE: yes; Version: 0x11 Composite: yes; Version: 0x4 RENDER: yes; Version: 0xb XFIXES: yes; Version: 0x50 SYNC: yes; Version: 0x31 GLX: yes; Version: 0x0 Decoration ========== Plugin: org.kde.breeze Theme: Blur: 0 onAllDesktopsAvailable: false alphaChannelSupported: true closeOnDoubleClickOnMenu: true decorationButtonsLeft: 0, 2 decorationButtonsRight: 3, 4, 5 borderSize: 3 gridUnit: 12 font: Noto Sans,10,-1,5,50,0,0,0,0,0,Regular smallSpacing: 3 largeSpacing: 12 Platform ========== Name: DRM Active: true Atomic Mode Setting: true Options ======= focusPolicy: 0 nextFocusPrefersMouse: false clickRaise: true autoRaise: false autoRaiseInterval: 0 delayFocusInterval: 0 shadeHover: false shadeHoverInterval: 250 separateScreenFocus: false placement: 4 focusPolicyIsReasonable: true borderSnapZone: 10 windowSnapZone: 10 centerSnapZone: 0 snapOnlyWhenOverlapping: false rollOverDesktops: true focusStealingPreventionLevel: 1 legacyFullscreenSupport: false operationTitlebarDblClick: 5000 operationMaxButtonLeftClick: 5000 operationMaxButtonMiddleClick: 5015 operationMaxButtonRightClick: 5014 commandActiveTitlebar1: 0 commandActiveTitlebar2: 30 commandActiveTitlebar3: 2 commandInactiveTitlebar1: 4 commandInactiveTitlebar2: 30 commandInactiveTitlebar3: 2 commandWindow1: 7 commandWindow2: 8 commandWindow3: 8 commandWindowWheel: 31 commandAll1: 10 commandAll2: 3 commandAll3: 14 keyCmdAllModKey: 16777251 showGeometryTip: false condensedTitle: false electricBorderMaximize: true electricBorderTiling: true electricBorderCornerRatio: 0.25 borderlessMaximizedWindows: false killPingTimeout: 5000 hideUtilityWindowsForInactive: true inactiveTabsSkipTaskbar: false autogroupSimilarWindows: false autogroupInForeground: true compositingMode: 1 useCompositing: true compositingInitialized: true hiddenPreviews: 1 glSmoothScale: 2 xrenderSmoothScale: false maxFpsInterval: 16666666 refreshRate: 0 vBlankTime: 6000000 glStrictBinding: false glStrictBindingFollowsDriver: true glCoreProfile: true glPreferBufferSwap: 101 glPlatformInterface: 2 windowsBlockCompositing: true Screen Edges ============ desktopSwitching: false desktopSwitchingMovingClients: false cursorPushBackDistance: 1x1 timeThreshold: 150 reActivateThreshold: 350 actionTopLeft: 0 actionTop: 0 actionTopRight: 0 actionRight: 0 actionBottomRight: 1 actionBottom: 0 actionBottomLeft: 0 actionLeft: 0 Screens ======= Multi-Head: no Active screen follows mouse: no Number of Screens: 1 Screen 0: --------- Name: SAM DP-3-U28D590 Geometry: 0,0,3840x2160 Scale: 1 Refresh Rate: 59.997 Compositing =========== Compositing is active Compositing Type: OpenGL OpenGL vendor string: X.Org OpenGL renderer string: AMD Radeon (TM) RX 480 Graphics (POLARIS10 / DRM 3.23.0 / 4.15.0-rc1-g516fb7f2e73d, LLVM 6.0.0) OpenGL version string: 4.5 (Core Profile) Mesa 17.4.0-devel (git-b6b4b2c6d8) OpenGL platform interface: EGL OpenGL shading language version string: 4.50 Driver: Unknown GPU class: Unknown OpenGL version: 4.5 GLSL version: 4.50 Mesa version: 17.4 Linux kernel version: 4.15 Direct rendering: Requires strict binding: no GLSL shaders: yes Texture NPOT support: yes Virtual Machine: no OpenGL 2 Shaders are used Painting blocks for vertical retrace: no Loaded Effects: --------------- kwin4_effect_dialogparent kwin4_effect_fade kwin4_effect_frozenapp kwin4_effect_login kwin4_effect_logout kwin4_effect_maximize kwin4_effect_morphingpopups kwin4_effect_translucency kwin4_effect_windowaperture slidingpopups slide screenshot minimizeanimation desktopgrid colorpicker presentwindows highlightwindow blur contrast startupfeedback screenedge kscreen Currently Active Effects: ------------------------- blur contrast Effect Settings: ---------------- kwin4_effect_dialogparent: kwin4_effect_fade: kwin4_effect_frozenapp: kwin4_effect_login: kwin4_effect_logout: kwin4_effect_maximize: kwin4_effect_morphingpopups: kwin4_effect_translucency: kwin4_effect_windowaperture: slidingpopups: fadeInTime: 75 fadeOutTime: 125 slide: screenshot: minimizeanimation: desktopgrid: zoomDuration: 150 border: 10 desktopNameAlignment: 0 layoutMode: 0 customLayoutRows: 2 usePresentWindows: true colorpicker: presentwindows: layoutMode: 0 showCaptions: true showIcons: true doNotCloseWindows: false ignoreMinimized: false accuracy: 20 fillGaps: true fadeDuration: 75 showPanel: false leftButtonWindow: 1 rightButtonWindow: 2 middleButtonWindow: 0 leftButtonDesktop: 2 middleButtonDesktop: 0 rightButtonDesktop: 0 highlightwindow: blur: blurRadius: 12 cacheTexture: true contrast: startupfeedback: type: 1 screenedge: kscreen:
I'm affected by this bug too. I can add that Kmail is not the only application that provocks this glitch : Akregator does too. Plasma 5.11.3 KDE Frameworks 5.40 KDE Applications 17.08 Qt 5.9.3 Arch Linux 4.14 Mesa 17.2.6 on Intel Modesetting (HD4000)
*** Bug 385678 has been marked as a duplicate of this bug. ***
I found another application, that is creating the same flickering. 1.) Open systemsettings as a maximized window 2.) Go to "Display and Screen" and then either to the "Display" or the "Compositor" section 2.) Open e.g. konsole as a maximized window on top of it (do not minimize systemstettings) 3.) Scroll through the "File" menu in konsole => Now the screen will flicker and systemsettings draws like it would be the application on top.
I can reproduce the bug (including as in comment 9) in KDE Neon User Edition (Plasma 5.11.5, Frameworks 5.41.0) on Intel Broadwell hardware and mesa 17.2.4. It's really nasty!
*** Bug 388837 has been marked as a duplicate of this bug. ***
I got some findings based on comment #9. Instead of using konsole I tried with kwrite and observed the same flickering if kwrite is started with platform wayland, but no flickering if started with platform xcb. Through the KWin debug console I investigated the difference of those two kwrites and observed that the Wayland variant uses RGBA (for whatever reason), while the X11 variant uses RGB. That the flickering is related to use of transparency makes sense in the context of the bug fix I already did. So overall I'm slightly optimistic to now being able to find the actual issue.
I did some fast testing with kwin-git on Arch Linux and KDE Frameworks 5.42. First, I didn't compile any other packages, so I might have missed another required change, if yes please let me know. I still get the flickering. I just have to open Kmail maximized and move the mouse up and down in the "Files" menu, it either disappears or is flickering. I tested as well with an application on top like Kwrite, but this also didn't really change.
The update to Plasma 5.12 beta didn't help either, flickering is still there on a Intel and AMD GPU. Do you see the same graphical glitches or do you need any futher information?
I'm pretty sure I see the same. And I fear I won't have the time to fix it before 5.12 final release. But at least I have a very good idea of what goes wrong.
I'm affected by this bug on Arch Linux running plasma 5.12 beta. I have intel hd graphics, modesetting driver.
As this is just a flickering, for me it is not critical and can wait after the Plasma 5.12 release. And I can work around the flickering by minimizing Kmail when not required or changing the size of the systemsettings window to get the updated content. Thanks
About minimizing Kmail : https://bugs.kde.org/show_bug.cgi?id=389143 And : https://bugs.kde.org/show_bug.cgi?id=387405
@tromzy@free.fr: Both bug reports are not related to this one from my point of view. I'm a normal Arch Linux user as well and minimizing Kmail works for me with Plasma 5.11 and 5.12 beta. I either close Kmail or I mimize to the panel.
*** Bug 389053 has been marked as a duplicate of this bug. ***
Adding some investigation results: * the observed flickering is "just" buffer age * on a multi-screen setup the issue can only be reproduced on the first screen (which has buffer age enabled) * the flickering frames are fine. E.g. for moving the cursor over a menu only the changed area is repainted. The flickering comes from the aged buffer * which means the root problem is that a buffer is painted with incorrect damage information Why that is the case I couldn't figure out yet.
With KDE Applications 18.04 I don't see the flickering in Kmail anymore, at least on my Intel notebook. Will test on my AMD machine and report if it works well. Linux 4.16, Plasma 5.12.4, KDE Frameworks 5.45
I'm on Applications 18.04 and I don't seem to be affected by this bug anymore, either.
My AMD systems don't show the flickering anymore. For me this bug is fixed with KDE Applications 18.04.
I'm reopening. I don't doubt you that the symptoms are fixed, but this is a KWin bug. No change in KMail can fix it.
I did my test on 3 systems now, 1 Intel and 2 AMD GPU's. I run Linux 4.16.3, Mesa 18.0.1, Qt 5.10.1, Plasma 5.12.4, KDE Frameworks 5.45 and KDE Applications 18.04. Looking at the update log, Mesa was updated from 18.0 to 18.0.1 as well at the same time.
The Mesa downgrade didn't change anything. So yes, somehow the symptoms are gone in the case of Kmail. Don't know if it is related, but in another scenario I can still reproduce a flickering in systemsettings https://bugs.kde.org/show_bug.cgi?id=391615.
The only change that happened with KDE Applications 18.04 was that Kmail enforces the xcb backend. And by this it tricked me still believing it would run on Wayland as it did before. Sorry to bother you, but I didn't expect this as Plasma 5.12 declared Wayland as stable.
in plasma 5.14 beta (Arch) I can reproduce the same flickering in window decoration kcm. Click "get new decoration" button, drag the window... enjoy flickering.
I also have the same problem with kmail, random flickering and it's nearly always the case when I open a new window inside kmail (file selector, email compositor...). I'm using an intel integrated gpu. Happy to help if there is anything specific I can try.
The bug started again on my side, too. When I open a window inside Kmail (mostly "Compose new message"), I get insane flickering and graphics corruption. Setting the windows fullscreen seem to fix it though.
I'm affected by this bug as well. Kmail: 18.08.1 Kwin: 5.13.5
(In reply to Patrick Silva from comment #29) > in plasma 5.14 beta (Arch) I can reproduce the same flickering in window > decoration kcm. Click "get new decoration" button, drag the window... enjoy > flickering. Did anyone test it with 5.14.2? Debian testing is still at 5.13.5. This so far is the biggest annoyance that prevents me from using Wayland Plasma session.
Created attachment 115956 [details] plasma 5.14.2, Arch Linux Screencast showing Arch Linux running plasma 5.14.2, frameworks 5.51.
For the person who asked, it still occurs on Plasma 5.14.3.
I'm also affected. Intel Haswell Graphics KMAIL 5.9.3 (18.08.3) Operating System: KDE neon 5.14 KDE Plasma Version: 5.14.3 Qt Version: 5.11.2 KDE Frameworks Version: 5.52.0 Processors: 4 × Intel® Core™ i7-4600U CPU @ 2.10GHz Memory: 15,1 GiB of RAM
Just tested it with Plasma 5.14.3 since it's now available in Debian. The issue is a bit less severe, but still plagues Kmail.
One potential way to work around the bug: * Disable buffer age: KWIN_USE_BUFFER_AGE=0 startplasmacompositor * Select "Full screen repaints" in System Settings > Display and Monitor > Compositor > Tear prevention ("vsync") Though it may cause performance issues. Also, it seems like running KWin/Wayland without buffer age support causes lots of visual artifacts, unless you have full screen repaints.
I did some investigation... It looks like this bug is caused by us not properly rendering subsurfaces.
> not properly rendering subsurfaces. In question. It's still not clear why the flickering occurs.
Created attachment 117441 [details] eye-candy flickering Some further investigation... Apparently, sometimes we don't draw windows atop subsurfaces.
Finally! I figured out. The problem is that we don't have quads for subsurfaces, thus https://phabricator.kde.org/source/kwin/browse/master/plugins/scenes/opengl/scene_opengl.cpp$1121-1144 won't be able to clip them when m_hardwareClipping is false.
(In reply to Vlad Zagorodniy from comment #42) > https://phabricator.kde.org/source/kwin/browse/master/plugins/scenes/opengl/ > scene_opengl.cpp$1121-1144 won't be able to clip them when > m_hardwareClipping is false. Do you have some patch to test a fix for this?
(In reply to Shmerl from comment #43) > Do you have some patch to test a fix for this? No, the fix isn't that trivial.
Good find, anyway! Hopefully this will be fixed soon.
Is this fix already part of Plasma 5.15 beta?
(In reply to Rainer Finke from comment #46) > Is this fix already part of Plasma 5.15 beta? I picked wrong verb. There is no currently any fix.
Thanks for your answer! Ok, this explains than why I got a flickering when kmail is open as a non maximized window and I open kate as well as a non maximized window.
(In reply to Rainer Finke from comment #48) > Thanks for your answer! Ok, this explains than why I got a flickering when > kmail is open as a non maximized window and I open kate as well as a non > maximized window. It happens with Kmail the most, but can happen with a few other programs as well.
it also happens with gwenview when opengl animations are enabled in gwenview settings.
*** Bug 402241 has been marked as a duplicate of this bug. ***
I did upgrade to Plasma 5.15 and I wanted to review the changes in systemsettings, but the flickering and graphical corruptions make it sometimes impossible to use it or to work with other applications (if systemsettings is not fully minimized). With Kmail I have still smilar issues. This bugs lets Plasma on Wayland appear less stable than it actually is. OS Arch Linux KDE-Plasma-Version: 5.15.0 KDE-Frameworks-Version: 5.55.0 Qt-Version: 5.12.1 Kernel-Version: 4.20.7-arch1-1-ARCH
*** Bug 403311 has been marked as a duplicate of this bug. ***
(In reply to Vlad Zagorodniy from comment #47) > > I picked wrong verb. There is no currently any fix. Is it clear what needs fixing though or how to fix it, or so far it's not even known?
See comment #42
(In reply to Martin Flöser from comment #55) > See comment #42 Does it require KWin redesign in some way, or the fix is just not trivial?
Where does redesign start and non trivial end? Some would say it's a redesign, some would say it's just non trivial.
Well, if it requires changing some taken approaches, that's redesign already.
Current Scene abstractions are good enough on X11, but not on Wayland. This causes some troubles for us, e.g. KWin will redraw all subsurface tree if any subsurface is damaged, etc. I think it won't be that hard to come up with new abstractions that would work for non-transformed windows. On the other hand, when effects like Wobbly Windows step in, things become a bit complex... :( Anyway, Bugzilla isn't the best place to discuss such things.
Yes, desktop effects like wobbling windows, magic lamp and desktop cube clearly show that the Wayland applications like systemsettings, Kmail and Firefox are not rendered correctly, so the flickering probably is just most obvious to a normal user.
To add: scene was pretty much the first part of KWin adjusted for Wayland. This part was ported before sub surface protocol was added. Unfortunately sub surfaces change the assumption. Vlad: an idea for a quick hack: trigger fullscreen repaints whenever there's a subsurface involved.
Relevant discussion: https://phabricator.kde.org/T10530
Is there any progress beyond the proposed approach?
*** Bug 418455 has been marked as a duplicate of this bug. ***
Git commit f2c8981f7e5fe9cd18a72888a2f199f483e8e983 by Vlad Zahorodnii. Committed on 04/05/2020 at 12:36. Pushed by vladz into branch 'master'. [scene] Generate window quads for sub-surfaces No window quads are generated for sub-surfaces right now. This leads to issues with effects that operate on window quads, e.g. magic lamp and wobbly windows. Furthermore, the OpenGL scene needs window quads to properly clip windows during the rendering process. The best way to render sub-surfaces would be with a little help from a scene graph. Contrary to GNOME, KDE hasn't developed any scene graph implementation that we could use in kwin. As a short term solution, this change adjusts the scene to generate window quads. Window quads are generated as we traverse the current window pixmap tree in the depth-first search manner. In order to match a list of quads with a particular WindowPixmap, we assign an id to each quad. FIXED-IN: 5.19.0 Differential Revision: https://phabricator.kde.org/D29131 M +159 -151 plugins/scenes/opengl/scene_opengl.cpp M +22 -12 plugins/scenes/opengl/scene_opengl.h M +99 -28 scene.cpp M +34 -0 scene.h https://commits.kde.org/kwin/f2c8981f7e5fe9cd18a72888a2f199f483e8e983
*** Bug 410729 has been marked as a duplicate of this bug. ***
*** Bug 419797 has been marked as a duplicate of this bug. ***
*** Bug 421655 has been marked as a duplicate of this bug. ***
Could this be backported to Plasma 5.18.6 ? It is a very important fix for kde wayland usage which could then be included as an update to Kubuntu 20.04.
(In reply to Lemmiwinks from comment #69) > Could this be backported to Plasma 5.18.6 ? > It is a very important fix for kde wayland usage which could then be > included as an update to Kubuntu 20.04. No, the fix can't be backported to 5.18 branch because it requires some changes in kwayland.
I finally managed to run newer Plasma on Debian testing using this: https://www.preining.info/blog/2020/07/kde-plasma-status-update-2020-07-04/ So now I have 5.19.3, so I tried Plasma session again. Kmail still behaves very badly, so I don't think this issue is fixed or I'm missing something. Message pane in Kmail doesn't display anything for me and just flickers sometimes.
(In reply to Shmerl from comment #71) > So now I have 5.19.3, so I tried Plasma session again. Kmail still behaves I meant Wayland session. I'm back to X11 for now, since Kmail was practically unusable.
It might be some other subsurface-related issue.
(In reply to Vlad Zahorodnii from comment #73) > It might be some other subsurface-related issue. Should I open another bug and do you need any data to narrow this down? You can try reproducing it, it happens pretty consistently for me. Kmail version: 20.04.3.
There is also similar issue with Lokalize: https://bugs.kde.org/show_bug.cgi?id=424024
(In reply to Shmerl from comment #74) > Should I open another bug and do you need any data to narrow this down? You > can try reproducing it, it happens pretty consistently for me. Yes, please create a new bug report. It would be nice to have some WAYLAND_DEBUG output.
Created attachment 130823 [details] kmail wayland log Here is a log from a quick kmail session. Things I did during that time: - I was trying to open emails in the message preview area (only flickering there). - I navigated to a folder with new emails. - Tried to scroll up to the new messages (more flickering) - Then selected one of the new emails to view it (at least that’s what I think I did).