AMDGPU DMCUB errors + flip_done timed out leading to desktop freeze on Pop!_OS (COSMIC DE)

[chirzul]

Describe the bug
The system randomly freezes during normal desktop usage on Pop!_OS with COSMIC Desktop Environment. Before the freeze, the AMDGPU driver produces repeated DRM timeout errors and DMCUB diagnostic errors. Shortly after these logs appear, the display becomes unresponsive and the system requires a hard reboot.

To Reproduce
Steps to reproduce the behavior:

1. Start normal desktop session (COSMIC DE on Pop!_OS)
2. Use the system normally (browsing, apps, or multitasking)
3. Wait for an unknown period of time
4. System freezes shortly after repeated AMDGPU errors appear
   (Note: exact reproduction steps are not fully deterministic, issue appears intermittent.)

Expected behavior
The system should continue running normally without freezing.
If AMDGPU display timeouts occur, the GPU driver should recover without requiring a system reboot.

Screenshots
Not applicable (system freeze occurs at kernel/display level).
However, relevant kernel logs are included below.

Desktop (please complete the following information):

• OS: Pop!_OS 24.04 LTS
• Kernel: Linux pop-os 6.18.7-76061807-generic #202601231045177824932224.04~b44a3c3 SMP PREEMPT_DYNAMIC Fri M x86_64 x86_64 x86_64 GNU/Linux

Additional context
Kernel logs observed before freeze:
May 26 09:32:33 pop-os kernel: amdgpu 0000:03:00.0: [drm] ERROR dc_dmub_srv_log_diagnostic_data: DMCUB error - collecting diagnostic data
May 26 09:32:43 pop-os kernel: amdgpu 0000:03:00.0: [drm] ERROR [CRTC:80:crtc-0] flip_done timed out
May 26 09:37:02 pop-os kernel: amdgpu 0000:03:00.0: [drm] ERROR dc_dmub_srv_log_diagnostic_data: DMCUB error - collecting diagnostic data
May 26 09:38:18 pop-os kernel: amdgpu 0000:03:00.0: [drm] ERROR flip_done timed out
May 26 09:38:18 pop-os kernel: amdgpu 0000:03:00.0: ERROR [CRTC:80:crtc-0] commit wait timed out
May 26 09:38:28 pop-os kernel: amdgpu 0000:03:00.0: ERROR [PLANE:59:plane-3] commit wait timed out