The main link video should not be enabled until a proper video source has been provided to the source controller. Typically, the source device wants to read the EDID from the attached sink device to determine its capabilities, most importantly its preferred resolution and other resolutions that it supports should the preferred mode not be available. After a resolution has been determined, set the main stream attributes in the source controller (0x180–0x1B0). Enable the main stream (0x084) only when a reliable video source is available.
Note: The scrambler/descrambler must be reset after enabling the main link video. Before starting to transmit video, the source must initialize the scrambler and the link partner's descrambler. This is done by forcing a scrambler reset (0x0C0) before the main link is enabled.
Note: The TRANSFER UNIT size of the DisplayPort transmit controller can be set to 32/64 or any even number in between. This is system dependent (on RX buffer capabilities).