Thanks again
chewitt
for your earlier input and the test image with `drm-vc4-grabber`.
We've now completed extensive testing on a Pi 5 using your image `LibreELEC-RPi5.aarch64-12.80.2`, and a custom-built DRM test tool written in C.
Unfortunately, even the most basic DRM call — `drmModeGetResources()` — fails on `/dev/dri/card0` with:
❌ drmModeGetResources: Operation not supported
This error (EOPNOTSUPP) occurs consistently, regardless of whether Kodi is idle (GUI visible) or fullscreen video (TVHeadend live stream) is running. No connector or resource enumeration is possible at all.
To confirm this is not a tool issue, we built both Rust and C versions, cross-compiled on Debian 12, and tested cleanly on the Pi 5 with the default LibreELEC kernel and your custom image.
---
### What we're asking:
Would it be possible to enable support for at least `drmModeGetResources()` on `/dev/dri/card0`?
Ideally, either:
- Allow basic scanout access for screenshot tools (like Hyperion, or framebuffer readers)
- Or enable the DRM writeback connector (if supported on VC6)
We understand that security and rendering separation are design decisions on VC6, but right now it's blocking even read-only diagnostics that worked perfectly on the Pi 4.
---
Happy to share test logs, source code, or help with packaging/debugging if needed.
Thanks again for your time and continued support!
Henry
Here’s the test log from the Pi 5 run:
--- DRM Test Protocol: drm-vc6-grabber (C) on Raspberry Pi 5 ---
📦 System:
- Device: Raspberry Pi 5
- LibreELEC Image: LibreELEC-RPi5.aarch64-12.80.2 (by @chewitt)
- Kernel: default from image
- Kodi: active (idle menu & live TV tested)
🧰 Grabber Tool:
- Name: drmgrab-vc6
- Language: C (no Rust dependencies)
- Method: classic DRM ioctl calls (xf86drm / drmMode*)
- Build: cross-compiled on Debian 12 using aarch64-linux-gnu-gcc
🧪 Execution:
- Binary copied to: /storage/drmgrab-vc6
- Run manually via SSH: ./drmgrab-vc6
🎯 Result:
- drmModeGetResources() → fails immediately
- Error: "❌ drmModeGetResources: Operation not supported"
- Exit code: 1
📌 Observation:
- Happens both in Kodi GUI (idle) and during fullscreen video playback
- No connector/CRTC information available → no framebuffer access possible
- Tool works correctly on Pi 4 (same source)
✅ Conclusion:
- `drmModeGetResources()` is blocked on VC6 under LibreELEC
- Even read-only DRM access is suppressed
Display More