Best-Effort Round Robin (RR) CSI-2 Forwarding allows for combining sensor sources with different resolutions and timing to the same CSI-2 Tx output. By default, the RR forwarding of packets use standard CSI-2 method of video stream determination. No special ordering of CSI-2 packets are specified, effectively relying on the Virtual Channel Identifier (VC) and Data Type (DT) fields to distinguish video streams. Each image sensor is assigned a VC-ID to identify the source. Different data types within a virtual channel are also supported in this mode.

When receiving FPD-Link RAW packets from DS90UB9x3x-Q1, each image sensor is assigned a VC-ID to identify the source. Different data types within a virtual channel is also supported in this mode.

The forwarding engine forwards packets as they become available to the forwarding engine. In the case where multiple packets may be available to transmit, the forwarding engine typically operates in an RR fashion based on the input port from which the packets are received.

Best-effort CSI-2 RR forwarding has the following characteristics and capabilities:

• Uses Virtual Channel ID to differentiate each video stream
• Separate Frame Synchronization packets for each VC
• No synchronization requirements

This mode of operation allows input RX ports to have different video characteristics and there is no requirement that the video be synchronized between ports. The attached video processor would be required to properly decode the various video streams based on the VC and DT fields.

Best-effort forwarding is enabled by setting the CSIx_RR_FWD bits in the FWD_CTL2 register 0x21.