Which functions fail only when the dock is added?

Record the same power, data, and video test directly and through the dock to identify the implicated layer.

Control results

Make the baseline comparable

Hold the host, cable class, target device, display mode, power supply, and software state constant where possible. A direct pass plus dock fail implicates the added layer; it does not prove which dock component is defective.

Build a full isolation sequence · Check required dock functions