[root@localhost ~]# mlxconfig -d /dev/mst/mt4119_pciconf0 set 
LINK_TYPE_P1=2 LINK_TYPE_P2=2

Device #1:
----------

Device type:    ConnectX5       
Name:           MCX556A-ECA_Ax  
Description:    ConnectX-5 VPI adapter card; EDR IB (100Gb/s) and 100GbE; 
dual-port QSFP28; PCIe3.0 x16; tall bracket; ROHS R6
Device:         /dev/mst/mt4119_pciconf0

Configurations:                              Next Boot       New
         LINK_TYPE_P1                        IB(1)           ETH(2)          
         LINK_TYPE_P2                        IB(1)           ETH(2)          

 Apply new Configuration? (y/n) [n] : y
Applying... Done!
-I- Please reboot machine to load new configurations.