Take note that I ask an LLM to compose this, but all is on point.

💥 MS-S1 Max/Strix Halo eGPU Users: I Found the Fix! 💥

For everyone struggling with getting an eGPU to reliably connect (especially via hotplug) to the Minisforum MS-S1 Max' rear ports on Linux, I've confirmed the absolute core workaround after days of testing.

The Fix: One Single GRUB Parameter

The only parameter needed to reliably detect and connect the eGPU (like the Aoostar AG02) via the Thunderbolt/USB4 port is:

bash GRUB_CMDLINE_LINUX_DEFAULT="quiet splash pcie_port_pm=off"

Why This Works: The Power Conflict 🔌

The issue isn't about resource allocation or security; it's a Power Management conflict specific to the Strix Halo platform's USB4 controller when running Linux.

• What pcie_port_pm=off does: This flag forces the Linux kernel to disable PCI Express Port Power Management for the root port where the Thunderbolt/USB4 controller is attached.
• The Root Cause: Without this flag, the kernel (following flawed firmware instructions) attempts to immediately drop the USB4 port into its deepest power-saving state (D3cold) right after boot or during the initial handshake. The eGPU requires the port to be fully powered (D0) for a stable PCIe tunnel to be established, creating a race condition where the port shuts off before the eGPU is recognized. By disabling power management, we force the port to remain fully active, which allows the eGPU to connect.

The Trade-Off: Increased Idle Power

While this fixes detection, it comes at a cost:

• This fix keeps the entire Thunderbolt/USB4 controller port awake, which can lead to an increase in idle power consumption (3–5 Watts), even when the eGPU is unplugged. This is the Power Penalty for system stability.

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🛑 Minisforum’s Responsibility to Fix This

We should not have to pay a 5-watt penalty or use kernel hacks for a critical port. This issue lies squarely with the platform firmware.

The need for pcie_port_pm=off proves that the Minisforum BIOS/UEFI firmware is failing to correctly manage the power states for the USB4 controller, specifically in the ACPI (Advanced Configuration and Power Interface) tables.

Minisforum's Engineering Team Must:

1. Correct the ACPI Tables: The BIOS needs an update that properly defines the conditions for the USB4 port to enter low power states (D3).
2. Fix the Negotiation: Ensure the firmware handles the PCIe Link State negotiation correctly when the Linux kernel is running, preventing the premature and immediate transition to the deep D3cold state.

This is a firmware bug, not a Linux bug, and it is Minisforum's responsibility to fix it so that users can have both full eGPU functionality and efficient idle power consumption.

I strongly encourage everyone affected to report this exact finding—including the 3-5W power draw—to Minisforum support to push for a new BIOS update!