On HPD Assertion - 3.1 English

DisplayPort 1.4 TX Subsystem Product Guide
Document ID
PG299
Release Date
2022-10-19
Version
3.1 English
  1. Read the DPCD capabilities fields out of the sink device (0x00000 to 0x0000B) though the AUX channel.
  2. Determine values for lane count, link speed, enhanced framing mode, downspread control and main link channel code based on each link partners’ capability and needs.
  3. Write the configuration parameters to the link configuration field (0x00100 to 0x00101) of the DPCD through the AUX channel.
    Note: Some Sink devices’ DPCD capability fields are unreliable. Many source devices start with the maximum transmitter capabilities and scale back as necessary to find a configuration the Sink device can handle. This could be an advisable strategy instead of relying on DPCD values.
  4. Equivalently, write the appropriate values to the Source core’s local configuration space.
    1. LANE_COUNT_SET
    2. LINK_BW_SET
    3. ENHANCED_FRAME_EN
    4. PHY_CLOCK_SELECT