A followup: Just noticed I had a file in xorg.conf.d called 20- intel.conf. Not sure where this file came from (it's quite possible I made it myself when trying to debug something since forgotten) and it seemed more-or-less empty; it's entire contents are: Section "Device" Identifier "card0" Driver "intel" #Option "AccelMethod" "uxa" EndSection
Given those contents, I would've presumed there'd be no difference to the default settings. Yet if I remove that file from xorg.conf.d, the graphical issues that I was experiencing in kwin_x11 are gone! Stefan, I don't suppose you might have something similar going on with your system? Peace, Brendon On Sunday, October 27, 2019 12:06:25 P.M. EST Brendon Higgins wrote: > 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