https://bugs.kde.org/show_bug.cgi?id=514351
Bug ID: 514351
Summary: Thinkpad T14 Gen6 OLED panel: eDP output temporarily
removed during early modeset
Classification: Plasma
Product: kwin
Version First 6.5.4
Reported In:
Platform: Gentoo Packages
OS: Linux
Status: REPORTED
Severity: minor
Priority: NOR
Component: compositing
Assignee: [email protected]
Reporter: [email protected]
Target Milestone: ---
Created attachment 188336
--> https://bugs.kde.org/attachment.cgi?id=188336&action=edit
output of the ecommand above
SUMMARY
When I start Plasma with Wayland I experience a 2-4 second delay on starting
and tearing down the session when the display looks as if it is off. This is
more of an annoyance, with X there is no delay, so if I use the same wallpaper
picture for SDDM background + Plasma Splash Screen + Plasma desktop, the
switches are instant and seamless. With Wayland (SDDM on Wayland / on X
regardless) my display turns off for 2-4 seconds.
I am more than happy to provide any information, update packages re-compile the
kernel with different options or apply patches if it helps anyone.
I do not experience this when I run Plasma on X (everything is instant). I do
not experience this with Weston on Wayland (everything is instant).
This happens consistently and doesn't seem to be affected by anything else.
The logs suggest that the internal eDP panel is briefly removed and re-added by
the kernel during early modesetting: kwin_wayland_drm: Removing output …
name="eDP-1" This forces the compositor to tear down and revalidate DRM state,
causing a visible delay.
STEPS TO REPRODUCE
1. To isolate this issue from SDDM I stop any SDDM / greeter service
2. I start the kwin session manually from the console: KWIN_DRM_TIMINGS=1
KWIN_LOGGING=1 QT_LOGGING_RULES="kwin_*.debug=true" dbus-run-session
kwin_wayland --exit-with-session konsole 2>&1 | ts '[%H:%M:%S]' | tee
kwin_wayland.txt
OBSERVED RESULT
After I login and start the session from SDDM (Runs on Wayland) I experience a
2-4 second delay with black screen. This happens consistently at the beginning
and at the end of my kwin_wayland session. It does not happen when I run kwin
on X11. It is not affected by using or not using a splash screen.
EXPECTED RESULT
There is a seamless transition from SDDM to kwin without a black screen or
flicker.
SOFTWARE/OS VERSIONS
Windows:
macOS:
(available in the Info Center app, or by running `kinfo` in a terminal window)
Linux/KDE Plasma:
KDE Plasma Version: 6.5.4
KDE Frameworks Version: 6.20.0
Qt Version: 6.10.1
ADDITIONAL INFORMATION
CPU: AMD Ryzen AI 7 PRO 350 w/ Radeon 860M (microcode 0xb600037)
GPU: c4:00.0 Display controller: Advanced Micro Devices, Inc. [AMD/ATI] Krackan
[Radeon 840M / 860M Graphics] (rev d2)
System Memory: 32GB SO-DIMM DDR5-5600
Display(s): OLED 2880x1800@120
Type of Display Connection: eDP
Distro name and Version: Gentoo
Kernel version: 6.18.3-gentoo-gentoo-dist #1 (closed) SMP PREEMPT_DYNAMIC
Kernel commandline: amdgpu.dc=1 amdgpu.modeset=1
Linux Firmware: 20251125
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