SUMMARY When kwin_x11 starts on an Xorg screen with a 30bpp visual, the screen is totally black except for the cursor. The window manager is working normally, and it's still possible to toggle compositing on and off with alt-shift-F12. STEPS TO REPRODUCE 1. Get a laptop with Intel gpu (I used a i7-10710U, which has CML GT2) 2. Set X11 to 30bpp by dropping this config snippet to /etc/X11/xorg.conf.d/10-depth.conf: Section "Screen" Identifier "default" DefaultDepth 30 EndSection 3. Login! OBSERVED RESULT black screen EXPECTED RESULT A Plasma Desktop in its deep color magnificence. SOFTWARE/OS VERSIONS KDE Plasma Version: 5.18.5 (also tried with kwinft built from git master) KDE Frameworks Version: 5.70.0 Qt Version: 5.14.2 mesa: 20.1.1 libdrm: 2.4.100
Also important 1. Toggling compositing off fixes this issue 2. 30bpp + compositing works fine on another machine with an AMD gpu (but also different distro and different versions of everything).
I can confirm this issue with my hardware (Lenovo ThinkPad X1 Yoga gen 4, 10 bit screen, Intel GPU)
This fixes the black screen for me on Intel Comet Lake GT2: echo "export KWIN_OPENGL_INTERFACE=egl" >~/.config/plasma-workspace/env/use_egl.sh
I double checked, and I consistently get the black screen with XGL. amdgpu also needs EGL for 30bpp. Are there any blockers to switch the default to EGL?
*** Bug 417455 has been marked as a duplicate of this bug. ***
I am affected by the same. Gentoo ~amd64, amdgpu. Compositor is allowed to start with KDE. KDE Plasma Version: 5.19.4 KDE Frameworks Version: 5.73.0 Qt Version: 5.15.0 mesa: 20.2.0_rc2 libdrm: 2.4.102
I have NOT tried loading KDE since July 2021 with 30bpp but can +1 this bug for that time. Also have not tried using EGL therefore cannot confirm. Apologies for the delay on the report. Sapphire Radeon RX 570 w/ amdgpu and 30bpp resulted in a black KDE desktop with mouse pointer. System ran Arch Linux with all components up-to-date as of July 2021.
I can confirm this bug report and the EGL workaround with the following setup: Hardware: Dell UP3218K AMD Radeon RX 6900 XT Software: Debian Sid KDE Frameworks: 5.88.0 KDE Plasma: 5.23.4 Qt: 5.15.2 Mesa: 21.2.6 libdrm: 2.4.108
A possibly relevant merge request was started @ https://invent.kde.org/plasma/kwin/-/merge_requests/1955
Git commit e6fb6ff5d3b3c60b0f50a00ed8b7e351e3aaf9a1 by Vlad Zahorodnii, on behalf of Xaver Hugl. Committed on 31/01/2022 at 16:23. Pushed by vladz into branch 'master'. backends/x11/standalone: only use sRGB configurations with depth 24 Credit goes to Mario Kleiner, who bisected this issue. M +2 -12 src/backends/x11/standalone/glxbackend.cpp https://invent.kde.org/plasma/kwin/commit/e6fb6ff5d3b3c60b0f50a00ed8b7e351e3aaf9a1
Git commit 8732958ce117979e7763d4c6e656189b7e18702c by Xaver Hugl. Committed on 31/01/2022 at 18:12. Pushed by zamundaaa into branch 'Plasma/5.24'. backends/x11/standalone: only use sRGB configurations with depth 24 Credit goes to Mario Kleiner, who bisected this issue. (cherry picked from commit e6fb6ff5d3b3c60b0f50a00ed8b7e351e3aaf9a1) M +2 -12 src/backends/x11/standalone/glxbackend.cpp https://invent.kde.org/plasma/kwin/commit/8732958ce117979e7763d4c6e656189b7e18702c