What Causes the 2-Second Display Flash?
When you plug in a multi-port USB-C adapter, dongle, or external monitor, your internal screen frequently blanks out for 2 seconds before returning:
- DisplayPort Alternate Mode Re-negotiation: The Apple Silicon GPU must dynamically reallocate high-speed SERDES lanes between USB 3.2 data (10 Gbps) and DisplayPort video streams.
- Unshielded 2.4GHz USB 3.0 EMI Radiation: Cheap plastic dongles radiate electromagnetic interference that disrupts internal Wi-Fi antennas and the display eDP clock lines positioned right next to the left USB-C ports!
Stabilize your display assertions with DisplayGuard.