SUMMARY Artifacts only seem to happen in intel + opengl (not in xrender) and seems to be related to the blur effect. Please see the effect here: https://user-images.githubusercontent.com/45201036/49102131-0863ce00-f289-11e8-8bfb-aa2d79ecfa9a.gif STEPS TO REPRODUCE 1. Use BreezeEnhanced decoration (https://github.com/tsujan/BreezeEnhanced) 2. Enable Blur in Desktop Effects 3. Hover on buttons as shown in the gif above SOFTWARE/OS VERSIONS KDE neon 5.14 Plasma 5.14.4 Qt: 5.11.2 Frameworks: 5.52.0 ADDITIONAL INFORMATION I think this is a kwin bug because the same button decorations and animations in plasma (using applet-window-buttons, https://github.com/psifidotos/applet-window-buttons) do not cause any artifact. Previous discussion in a BreezeEnhanced issue: https://github.com/tsujan/BreezeEnhanced/issues/10
I just saw the artifact with the blur effect disabled, although it happens less frequently. This together with the fact that I haven't been able so far to reproduce these artifacts in vanilla Breeze decorations, make me think that the bug is uncovered by button animations, which are present in BreezeEnhanced.
Further information: Intel Haswell-ULT Integrated Graphics Controller (Lenovo). Using ubuntu's default intel driver xserver-xorg-video-intel-native-modesetting, which if I'm not wrong is integrated in linux kernel (i915). Opengl 3.0 mesa 18.0.5 (even though system settings says is opengl 3.1). Artifacts also appear in opengl 2.0, and distinct opengl settings in system settings do not resolve the issue.
Also, I experienced the same behavior in linux kernel 4.15 and 4.18.
Using intel xorg driver with minimal configuration (see below) does not fix the issue. Section "Device" Identifier "Intel Graphics" Driver "intel" EndSection Playing with intel xorg options might help but that is like seeking a needle in a haystack...
The issue seems to be present only when using sna AccelMethod in contrast to uxa. Will continue testing...
I had the same bug on my system some time ago, reported as bug 397215. I use haswell cpu and intel hd graphics with modesetting driver too. However I can't reproduce on my current system. Operating System: Arch Linux KDE Plasma Version: 5.14.4 Qt Version: 5.12.0 RC1 KDE Frameworks Version: 5.52.0
*** This bug has been marked as a duplicate of bug 397215 ***
(In reply to Patrick Silva from comment #6) > I had the same bug on my system some time ago, reported as bug 397215. > I use haswell cpu and intel hd graphics with modesetting driver too. > However I can't reproduce on my current system. > > Operating System: Arch Linux > KDE Plasma Version: 5.14.4 > Qt Version: 5.12.0 RC1 > KDE Frameworks Version: 5.52.0 Mmm, interesting, it might then be an issue in Qt, which is fixed in Qt 12
(In reply to Patrick Silva from comment #6) > I had the same bug on my system some time ago, reported as bug 397215. > I use haswell cpu and intel hd graphics with modesetting driver too. > However I can't reproduce on my current system. > > Operating System: Arch Linux > KDE Plasma Version: 5.14.4 > Qt Version: 5.12.0 RC1 > KDE Frameworks Version: 5.52.0 Patrick, may I ask you what intel driver are you using, kernel's or xorg's? if xorg's, are you using default sna or uxa?
I use modesetting driver, kernel 4.19.4.
(In reply to Patrick Silva from comment #10) > I use modesetting driver, kernel 4.19.4. I see. That's another difference. I use 4.18.0. Do you think the issue could be fixed by an update of the driver in the kernel? Did you or Could you test a kernel < 4.19 ?
(In reply to avlas from comment #1) > I just saw the artifact with the blur effect disabled, although it happens > less frequently. > > This together with the fact that I haven't been able so far to reproduce > these artifacts in vanilla Breeze decorations, make me think that the bug is > uncovered by button animations, which are present in BreezeEnhanced. Other people reported similar artifacts due to transparency, which is present here too. So, it might be related to that instead of to animations.
(In reply to Patrick Silva from comment #6) > I had the same bug on my system some time ago, reported as bug 397215. > I use haswell cpu and intel hd graphics with modesetting driver too. > However I can't reproduce on my current system. > > Operating System: Arch Linux > KDE Plasma Version: 5.14.4 > Qt Version: 5.12.0 RC1 > KDE Frameworks Version: 5.52.0 Forget. The problem has just happened again.
(In reply to Patrick Silva from comment #13) > (In reply to Patrick Silva from comment #6) > > I had the same bug on my system some time ago, reported as bug 397215. > > I use haswell cpu and intel hd graphics with modesetting driver too. > > However I can't reproduce on my current system. > > > > Operating System: Arch Linux > > KDE Plasma Version: 5.14.4 > > Qt Version: 5.12.0 RC1 > > KDE Frameworks Version: 5.52.0 > > Forget. The problem has just happened again. So bad. Btw, do you know if you have any level of transparency in your kwin decorations?
(In reply to avlas from comment #14) > So bad. > > Btw, do you know if you have any level of transparency in your kwin > decorations? transparency is disabled on my system. The problem only occurs here when I set fractional display scaling (1.2 factor).
(In reply to Patrick Silva from comment #15) > (In reply to avlas from comment #14) > > > So bad. > > > > Btw, do you know if you have any level of transparency in your kwin > > decorations? > > transparency is disabled on my system. > The problem only occurs here when I set fractional display scaling (1.2 > factor). I don't have fisplay scaling, but I have forced a higher dpi. Also, I think transparency may be present beyond the opacity setting (I think), e.g. in alpha colors and/or transparent background in kwin button decorations.