The Board Management software offers you to retrain the adapter card slot 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.

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

#dis_tool 

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

dis_tool [0,4] retrain-slot
Adapter No     : 0
Slot link retrained 
dis_tool [0,4] quit