[dpdk-users] Mellanox CX-5 failed with DPDK 20.05, but ok with DPDK 19.11.3

[Zhao, Ping]

Dear DPDK Users,

I met a problem with DPDK 20.05 + Mellanox CX-5 NIC. Does anyone know how to fix it? Thanks a lot!

Problem:
Mellanox CX-5 card ok with DPDK 19.11.3 but failed with DPDK 20.05.
20.05 Reports no ethernet device, ok with 19.11.3

Configuration:
Mellanox CX-5 OFED package: MLNX_OFED_LINUX-5.0-2.1.8.0-rhel8.1
DPDK 20.05
DPDK stable 19.11.3

Test:
              Test with DPDK testpmd app.

Logs:

Testpmd in DPDK 20.05
EAL: Detected 112 lcore(s)
EAL: Detected 2 NUMA nodes
EAL: Multi-process socket /var/run/dpdk/rte/mp_socket
EAL: Selected IOVA mode 'PA'
EAL: No available hugepages reported in hugepages-1048576kB
EAL: Probing VFIO support...
EAL: VFIO support initialized
EAL: No legacy callbacks, legacy socket not created
testpmd: No probed ethernet devices
testpmd: create a new mbuf pool <mbuf_pool_socket_0>: n=163456, size=2176, socket=0
testpmd: preferred mempool ops selected: ring_mp_mc
Done

Devices:
./usertools/dpdk-devbind.py --status

Network devices using kernel driver
===================================
0000:18:00.0 'MT28800 Family [ConnectX-5 Ex] 1019' if=ens785f0 drv=mlx5_core unused=vfio-pci
0000:18:00.1 'MT28800 Family [ConnectX-5 Ex] 1019' if=ens785f1 drv=mlx5_core unused=vfio-pci
0000:3d:00.1 'Ethernet Connection X722 for 10GBASE-T 37d2' if=eno2 drv=i40e unused=vfio-pci *Active*

# ibstat
CA 'mlx5_0'
        CA type: MT4121
        Number of ports: 1
        Firmware version: 16.27.2008
        Hardware version: 0
        Node GUID: 0x0c42a103003a1298
        System image GUID: 0x0c42a103003a1298
        Port 1:
                State: Active
                Physical state: LinkUp
                Rate: 100
                Base lid: 0
                LMC: 0
                SM lid: 0
                Capability mask: 0x00010000
                Port GUID: 0x0e42a1fffe3a1298
                Link layer: Ethernet
CA 'mlx5_1'
        CA type: MT4121
        Number of ports: 1
        Firmware version: 16.27.2008
        Hardware version: 0
        Node GUID: 0x0c42a103003a1299
        System image GUID: 0x0c42a103003a1298
        Port 1:
                State: Active
                Physical state: LinkUp
                Rate: 100
                Base lid: 0
                LMC: 0
                SM lid: 0
                Capability mask: 0x00010000
                Port GUID: 0x0e42a1fffe3a1299
                Link layer: Ethernet


Thanks,
Ping