Receive – Issues After Training - 3.1 English

DisplayPort 1.4 RX Subsystem Product Guide (PG300)

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3.1 English
This section contains debugging steps if the monitor is not displaying video even after a successful training or if the monitor display is noisy.
  1. If the video timing counters are reporting 0 lines, toggle the DTG enable and software-video reset and check again.
  2. Check the symbol and disparity error counters 0x448 and 0x44C through AXI reads. If the errors are accumulating, the alignment bit might go off eventually. Perform dprx_init once and toggle HPD so the source can train the sink again.
  3. Training lost can occur:
    • When there is change in link configuration and RX is in previously trained state
    • Either symbol lock/channel equalization/clock recovery failure
    • Lane inactivity