The Source device must debounce the incoming HPD signal by sampling the value at an interval > 250 µs. For a pulse width between 500 µs and 1 ms, the Sink device has requested an interrupt. The interrupt is passed to the host processor through the AXI4-Lite interface.
If HPD signal remains Low for > 2 ms, then the Sink device has been disconnected and the link should be shut down. This condition is also passed through the AXI4-Lite interface as an interrupt. The host processor must properly determine the cause of the interrupt by reading the appropriate DPCD registers and take the appropriate action. For details, see the VESA DisplayPort Standard v1.4.