Displaylink makes X sluggish and displays (temporary) artifacts when moving windows

On my new HP Elitebook, while displaylink is active everything feels sluggish, just as if acceleration was switched off, even stuff that happens on the monitor directly connected to the PC.

Only on the monitor managed by display link, artifacts (short horizontal lines) appear when moving windows, but fortunately go away on their own within a second after movement.

No source file or test is identified. Start by reproducing the report on an HP Elitebook with DisplayLink active, comparing responsiveness on the directly connected and DisplayLink-managed monitors while moving windows. Capture the driver, desktop, and display configuration, and define done as identifying a reproducible cause or a verified fix for the sluggishness and artifacts.

Written by the indexing model from the issue text.