In DCMAC FixedE mode, when a port is not in use, it can be decommissioned as follows:
- Set ctl_rx/tx_data_rate=0 (100G)
- Not necessary on ports 1, 3, 5 as these ports only support 100G and therefore have no data rate control
- Assert serdes reset and channel flush for the given port
- Set ctl_mem_disable_rx/tx_serdes_clk[port]=1 and ctl_mem_disable_rx/tx_flexif_clk[port]=1 to save power
The process is the same for the PHY side of the device in Independent mode, excluding the channel flush as the MAC and PHY are operating independently. On the MAC side, channel flush for a given channel is asserted to decommission that channel.