I have been running an RX 9070 XT (Navi 48, RDNA 4) as an eGPU via Thunderbolt 4 (ASUS Zenbook S 16, USB4 port) connected to a Minisforum DEG2 dock (TB5-capable, link negotiated at 40 Gb/s) with Arch Linux + KDE Plasma 6 Wayland.

After extensive testing, I have documented working solutions for:

1. Boot hang workaround — RDNA 4 eGPUs cause a boot hang due to DMCUB firmware init failure. A udev rule + systemd service defers initialization until after login.
2. Shutdown protection — A systemd service removes the eGPU from the PCI bus before shutdown, with reboot detection to preserve the Thunderbolt tunnel.
3. KDE Wayland primary GPU selection — Using KWIN_DRM_DEVICES to force iGPU as primary renderer.
4. Hot-unplug limitations — Documented failure modes and workarounds.

I would like to add these to the AMDGPU and Wayland sections. The proposed content is factual and tested. Happy to adjust formatting or placement based on feedback.

Hardware tested:

• Kernel: 6.19.9-arch1-1
• Mesa: 26.0.3
• KDE Plasma 6, KWin 6.6.2, Wayland
• GPU: RX 9070 XT (1002:7550)
• Dock: Minisforum DEG2 (Thunderbolt 5)

Arny80Hexa (talk) 12:30, 22 March 2026 (UTC)

Feel free to start a Troubleshooting section at the bottom of the page. — Lahwaacz (talk) 08:28, 26 April 2026 (UTC)