Can I set the 40G speed of the mellanox SN2100?


I have a Mellanox SN2100 switch for my DC and bought it in July, a few days ago, I find I can’t use the 40G optical transceiver on all the ports,the datasheet says it can support the 40G cables and optical transceivers. The system is cumulus linux, when I use the command of " netshow interface",it shows the speed of all ports are 100G,Also,the 100G optical transceivers will be ok,but the 40G can’t link with the other one,even the cables,So I’m so puzzled.Can I set the 40G speed of the mellabox SN2100? if yes,can you offer it? or are there some links I can find it? your helps will be appreciated. Thanks so much!