The Board Management software offers you to retrain the cable link to a faster speed or wider width without bringing down the link. This may be useful for debugging if the link negotiation for some reason did not reach maximum capabilities or if you wold like to hot add additional cables to an operational link.

To retrain the link to maximum capabilities, use the dis_tool utility and the command 'retrain-link'.

#dis_tool 

dis_tool version 5.14.0 (rev f8ba7b5 Fri Aug  9 13:17:10 CEST 2019)

dis_tool [0,4] retrain-link

Adapter No        : 0
Link No [0-3]     : 0
Cable link 0 retrained 
dis_tool [0,4] quit