Anyone familiar with the Dell P2421DC? I'm trying to get the USB ports (four of them) to work. The manual says to connect a USB-C cable between the display and a similar port on the computer. It's unclear from the doc whether that means in addition to (say) an HDMI cable to drive the display (so, USB-C cable just services the USB ports), or instead of (so, the USB-C cable drives the display *and* handles the USB ports).
Neither arrangement works for the ports, but either cable by itself drives the display OK.