https://bugs.kde.org/show_bug.cgi?id=522744
Bug ID: 522744
Summary: Atomic modeset commit fails repeatedly (EINVAL) for
1440x900 output on amdgpu, causing screen
duplication/flicker at Plasma Login greeter
Classification: Plasma
Product: kwin
Version First unspecified
Reported In:
Platform: CachyOS
OS: Linux
Status: REPORTED
Severity: normal
Priority: NOR
Component: platform-drm
Assignee: [email protected]
Reporter: [email protected]
CC: [email protected]
Target Milestone: ---
Atomic modeset commit fails repeatedly (EINVAL) for 1440x900 output on amdgpu,
causing screen duplication/flicker at Plasma Login greeter
**Summary**
On a dual-monitor setup with mismatched native resolutions
(1920x1080 via DisplayPort + 1440x900 via VGA) on an AMD Ryzen 7 5700G
integrated GPU (amdgpu, Renoir/Cezanne), the kwin_wayland instance
started by Plasma Login Manager for the greeter repeatedly fails to
commit an atomic modeset for the 1440x900 output, logging dozens of
consecutive failures within about a second:
kwin_wayland[PID]: Atomic modeset commit failed! Argumento inválido
amdgpu 0000:30:00.0: [drm] Mode Validation Warning: Unknown Status failed
validation.
This causes the greeter screen to visually flicker/duplicate multiple
times until a mouse click forces a repaint that stabilizes it. This
happens 100% of the time on every login/logout.
Additionally, immediately after authenticating and starting the real
Plasma Wayland session, kwin_wayland logs:
kwin_wayland[PID]: Failed to find a working output layer configuration!
Enabled layers:
kwin_wayland[PID]: src KWin::RectF(0,0 1440x900) -> dst KWin::Rect(0,0
1440x900)
kwin_wayland[PID]: Applying output configuration failed!
kwin_wayland[PID]: atomic commit failed: Permiso denegado
Despite this, the actual Plasma session (once logged in) displays
both monitors correctly as an extended desktop with no visible issues.
Only the greeter/transition stage is affected.
**Steps to reproduce**
1. Connect a 1920x1080 monitor via DisplayPort and a 1440x900 monitor
via VGA to an AMD Ryzen 7 5700G (Cezanne/Renoir iGPU, amdgpu driver).
2. Configure extended desktop (not mirrored) from within the Plasma
session — confirmed working correctly.
3. Log out or reboot to the Plasma Login Manager greeter.
4. Observe repeated "Atomic modeset commit failed! Argumento inválido"
errors in the journal and visible flicker/duplication on screen.
5. Click anywhere -> display stabilizes.
**Software/Hardware**
- OS: CachyOS Linux
- KDE Plasma: 6.7.2
- KDE Frameworks: 6.27.0
- Qt: 6.11.1
- Kernel: 7.1.3-1-cachyos (64-bit)
- Graphics platform: Wayland
- GPU: AMD Ryzen 7 5700G with Radeon Graphics (Cezanne, RENOIR 0x1002:0x1638),
amdgpu driver, kernel module version bundled with kernel 7.1.3-1-cachyos
- Displays: Samsung Electric Company C24FG70 (1920x1080, DisplayPort), Dell
Inc. DELL P1911 (1440x900, VGA)
- Display manager: Plasma Login Manager (plasmalogin)
**Journal excerpt (greeter start, repeated ~20x within 1 second)**
kwin_wayland[855]: Atomic modeset commit failed! Argumento inválido
amdgpu 0000:30:00.0: [drm] Mode Validation Warning: Unknown Status failed
validation.
[... repeats ~20 times ...]
**Journal excerpt (session start, right after login)**
kwin_wayland[7813]: Failed to find a working output layer configuration!
Enabled layers:
kwin_wayland[7813]: src KWin::RectF(0,0 1440x900) -> dst KWin::Rect(0,0
1440x900)
kwin_wayland[7813]: Applying output configuration failed!
kwin_wayland[7813]: atomic commit failed: Permiso denegado
[Adjuntar journal_flicker.log completo y dmesg_flicker.log]
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