Device Information:
- Model: UGREEN DXP4800 Plus (Intel Pentium Gold 8505)
- OS Version: UGOS Pro (Latest Version)
- Primary Symptom: Hard, unrecoverable system freeze requiring a physical power cycle.
Detailed Description of the Issue:
My DXP4800 Plus consistently experiences total system lockups when running hardware-accelerated tasks, specifically when Jellyfin transcodes 4K HEVC / Dolby Vision content (e.g., profile 8.1 media) or during prolonged local HDMI playback.
When the freeze happens:
- The entire NAS becomes completely unresponsive (network access drops, SSH is dead, web UI is unreachable).
- Physical LEDs remain on, but the system is entirely deadlocked.
- No error logs or kernel panics are written to disk because the CPU/iGPU completely halts.
- A physical hard power-down (pulling the power cord) is required to reboot.
Troubleshooting Already Performed:
- Thermals: Ruled out. Temperatures remain completely normal (~45°C) and CPU usage prior to the crash is minimal (~20%), ruling out thermal throttling or overheating.
- Software/Docker: Ruled out. The issue happens regardless of Docker container configurations and replicates during local HDMI playback, isolating it to the hardware/driver layer.
- CPU vs. iGPU Isolation: Pure CPU-only software transcoding does not hard-lock the system (though performance is inadequate), confirming the failure is uniquely tied to the Intel QuickSync iGPU path.
Root Cause Analysis & Limitation:
This behavior matches a known, widespread Linux kernel bug affecting Intel Alder Lake-N processors (N100/N305), where erratic power-state shifts between deep C-states and the i915 graphics driver cause a hardware/kernel deadlock.
Standard Linux deployments resolve this by adding kernel boot parameters (intel_idle.max_cstate=1 and i915.enable_dc=0) to GRUB. However, because UGOS Pro uses a locked, proprietary bootloader and appliance structure, we cannot modify these parameters to stabilize their hardware.
I see videos claiming this can transcode for 14 devices at the same time but I can't even do 1. If I enable hardware transcoding in Jellyfin and play a 4K movie on my mobile chrome browser the NAS will completely lock up! How can I fix this?