LINK TRAINING IN MULTIMEDIA INTERFACES

A source device and a sink device perform a link training process on a multimedia interface cable. The sink device includes one or more request registers. During the link training process, the sink device stores request codes in the request registers. Each request code is a request for the source device to perform a certain action. The source device reads the request codes and performs the corresponding actions. For example, if the source device reads request codes to send one or more training pattems, then the source device sends the training patterns over the multimedia link. In response to receiving the training patterns, the sink device can selects one or more updated request codes (e.g., to send different training patterns or to adjust link parameters, such as the link rate or a pre-emphasis level).