Did you installed HCA into the correct port? What is the output of lspci -s 02:00.0 -xxx
ibv_devinfo -vvv
Could you use small switch instead of connecting back-to-back and check if the issue still happens?
Did you installed HCA into the correct port? What is the output of lspci -s 02:00.0 -xxx
ibv_devinfo -vvv
Could you use small switch instead of connecting back-to-back and check if the issue still happens?