https://bugs.kde.org/show_bug.cgi?id=523958
Bug ID: 523958
Summary: ThinkPad T495 freezes immediately when external
monitor or Dell WD22TB4 dock is connected on Wayland
Classification: Plasma
Product: kwin
Version First 6.7.4
Reported In:
Platform: CachyOS
OS: Linux
Status: REPORTED
Severity: normal
Priority: NOR
Component: wayland-generic
Assignee: [email protected]
Reporter: [email protected]
Target Milestone: ---
Hardware
========
Laptop:
- Lenovo ThinkPad T495
CPU:
- AMD Ryzen 5 PRO 3500U
GPU:
- AMD Radeon Vega 8 (amdgpu)
Dock:
- Dell WD22TB4
Software
========
Distribution:
- CachyOS (latest)
Kernel:
- 7.1.6-1-cachyos
Plasma:
- 6.7.4
KWin:
- 6.7.4
Mesa:
- 26.1.6
Session:
- Wayland
Problem
=======
I am experiencing two related external display issues.
1) Dell WD22TB4 dock
Immediately after connecting the dock, the Plasma Wayland session freezes
completely.
Symptoms:
- Mouse freezes.
- Keyboard becomes unresponsive.
- Desktop stops updating.
- No black screen.
- Requires a hard power-off.
2) HDMI connected directly to the laptop
Connecting a monitor directly to the HDMI port does NOT freeze the system.
However:
- The external monitor is never detected.
- Plasma continues running normally.
- The laptop display remains the only detected display.
Expected Result
===============
Connecting either:
- Dell WD22TB4 dock
or
- HDMI directly to the laptop
should detect the external monitor without freezing the desktop.
Additional Information
======================
This issue is reproducible on BOTH:
- CachyOS + KDE Plasma
- Arch Linux + KDE Plasma
The exact same hardware works correctly with:
- Arch Linux + Niri (Wayland)
External displays work correctly under Niri.
This strongly suggests the issue is specific to KDE Plasma / KWin rather than:
- AMDGPU
- Mesa
- Linux kernel
- hardware
Diagnostic Information
======================
kscreen-doctor -o only reports the internal display.
cat /sys/class/drm/*/status reports:
disconnected
disconnected
connected
disconnected
Only the internal eDP panel is ever reported as connected, even with HDMI
attached.
Graphics Information
====================
GPU:
AMD Radeon Vega 8 Graphics
Driver:
amdgpu
Renderer:
AMD Radeon Vega 8 Graphics (radeonsi)
Kernel:
7.1.6-1-cachyos
Mesa:
26.1.6
Plasma:
6.7.4
KWin:
6.7.4
Additional Notes
================
I performed a completely fresh installation of CachyOS on a brand new SSD.
The problem existed immediately after installation before restoring any
configuration.
No custom KWin configuration or display configuration has been imported.
This is therefore not caused by old user configuration files.
I also disabled plasma-kscreen.service to rule out KScreen, but the problem
remained unchanged.
I would be happy to test patches or provide additional logs if needed.
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