Hi, I've encountered similar behaviour: black/residual/flickering windows making the desktop unusable after login. I also noticed some minor (white) flickering in SDDM prior to login, although it was still quite usable at that point. I'm running a mixed testing/unstable system, and am also using an Intel display chip (Dell Latitude; only on-board, no discrete graphics chip).
I found disabling OpenGL compositing with ALT+SHIFT+F12 worked around it at first, as did downgrading KDE+QT packages back to testing. I'm just trying this now with unstable packages again, and running the suggestsed 'DRI_PRIME=1 kwin_x11 --replace'also seems to work - even as the new kwin_x11 instance brings OpenGL compositing back with it. Peace, Brendon On Sun, 27 Oct 2019 01:15:10 +0200 Stefan Schwarzer <stefan.schwar...@gmx.net> wrote: > Package: kwin-x11 > Version: 4:5.14.5-1+b1 > Severity: important > > Dear Maintainer, > > I am following debian unstable, desktop X11/sddm/kde on a Lenovo laptop T460p. > The nvidia graphics on the laptop is disabled in favor of the chipset graphics > (Intel). > > After the last upgrade (which was from testing to stable on the 25th October), > I am experiencing a mostly unusable desktop. The login screen (sddm) comes up > as expected, > but right after login I get flickering black rectangles on the screen, which > may > cover up to 90% of its area. Windows mostly remain black or their content > suddenly > becomes visible he task bar remains black and I see other residuals of the kde > splash > screen where windows should be drawn or the background wallpaper be > restored. Swithing to a VT; all seems ok, kwin, the desktop and applications > are > running. > > So far, my only clue as to what may be going on is a workaroud: if I start a > terminal > via keyboard shortcut and issue blindly > DRI_PRIME=1 kwin_x11 --replace > then afterwards things behave mostly normally (Sometimes window contaent is > still > not correctly updated). I just picked this line up from older bug reports > against kwin on the net without understanding what it does. > > This is the output of kwin following this command in the hope that it helps > > OpenGL vendor string: Intel Open Source Technology Center > OpenGL renderer string: Mesa DRI Intel(R) HD Graphics 530 > (Skylake GT2) > OpenGL version string: 4.5 (Core Profile) Mesa 19.2.1 > OpenGL shading language version string: 4.50 > Driver: Intel > GPU class: Unknown > OpenGL version: 4.5 > GLSL version: 4.50 > Mesa version: 19.2.1 > X server version: 1.20.4 > Linux kernel version: 5.3 > Requires strict binding: yes > GLSL shaders: yes > Texture NPOT support: yes > Virtual Machine: no > > > > -- System Information: > Debian Release: bullseye/sid > APT prefers unstable > APT policy: (990, 'unstable'), (500, 'testing'), (500, 'stable'), (1, 'experimental') > Architecture: amd64 (x86_64) > Foreign Architectures: i386
