RTL8156 USB3.0 2.5G Ethernet

[   23.811632] cdc_ncm 8-1:2.0 usb0: network connection: disconnected
[   23.843634] cdc_ncm 8-1:2.0 usb0: network connection: disconnected
[   23.875676] cdc_ncm 8-1:2.0 usb0: network connection: disconnected
[   23.907672] cdc_ncm 8-1:2.0 usb0: network connection: disconnected
[   23.939633] cdc_ncm 8-1:2.0 usb0: network connection: disconnected
[   23.971625] cdc_ncm 8-1:2.0 usb0: network connection: disconnected
[   24.003665] cdc_ncm 8-1:2.0 usb0: network connection: disconnected

Floods no ethernet.

Works on Ubuntu Bionic x86 and also Armbian Rockpi4 Ubuntu Bionic 4.4
Manjaro Arm Rockpi4 the above as said just floods.

This is because the upstream driver doesn't support Realtek 8156 (yet).

Please ask Realtek to upstream their driver, and use [1] for the interim.

[1] https://www.realtek.com/en/component/zoo/category/network-interface-controllers-10-100-1000m-gigabit-ethernet-usb-3-0-software

Source

It doesn't need a driver its a cdc_ncm device from 4.16 should be enable CONFIG_USB_NET_CDC_NCM in make menuconfig and go.
The driver they released was for pre 4.16 non cdc_ncm kernels.
Hence it works fine on Armbian 4.4 so they must of backported patches but in Manjaro it doesn't work at all and there never will be specific Realtek drivers as they are not needed for CDC_NCM devices

Turned out to be a dodgy cable

[ 4175.958513] cdc_ncm 8-1:2.0 usb0: network connection: connected
[ 4175.990543] cdc_ncm 8-1:2.0 usb0: 2500 mbit/s downlink 2500 mbit/s uplink
[ 4176.022513] cdc_ncm 8-1:2.0 usb0: network connection: connected
[ 4176.054543] cdc_ncm 8-1:2.0 usb0: 2500 mbit/s downlink 2500 mbit/s uplink
[ 4176.086512] cdc_ncm 8-1:2.0 usb0: network connection: connected
[ 4176.118517] cdc_ncm 8-1:2.0 usb0: 2500 mbit/s downlink 2500 mbit/s uplink
[ 4176.150512] cdc_ncm 8-1:2.0 usb0: network connection: connected
[ 4176.182545] cdc_ncm 8-1:2.0 usb0: 2500 mbit/s downlink 2500 mbit/s uplink
[ 4176.214482] cdc_ncm 8-1:2.0 usb0: network connection: connected
[ 4176.246518] cdc_ncm 8-1:2.0 usb0: 2500 mbit/s downlink 2500 mbit/s uplink
[ 4176.278513] cdc_ncm 8-1:2.0 usb0: network connection: connected
[ 4176.310521] cdc_ncm 8-1:2.0 usb0: 2500 mbit/s downlink 2500 mbit/s uplink
[ 4176.342537] cdc_ncm 8-1:2.0 usb0: network connection: connected
[ 4176.374544] cdc_ncm 8-1:2.0 usb0: 2500 mbit/s downlink 2500 mbit/s uplink
[ 4176.406536] cdc_ncm 8-1:2.0 usb0: network connection: connected
[ 4176.438519] cdc_ncm 8-1:2.0 usb0: 2500 mbit/s downlink 2500 mbit/s uplink
[ 4176.470538] cdc_ncm 8-1:2.0 usb0: network connection: connected
[ 4176.502519] cdc_ncm 8-1:2.0 usb0: 2500 mbit/s downlink 2500 mbit/s uplink

Still floods but its working

Manjaro Arm 5.3 Slow server speed

[rock@rockpi4 ~]$ iperf3 -s
-----------------------------------------------------------
Server listening on 5201
-----------------------------------------------------------
Accepted connection from 192.168.1.12, port 52620
[  5] local 192.168.1.9 port 5201 connected to 192.168.1.12 port 52621
[ ID] Interval           Transfer     Bitrate
[  5]   0.00-1.00   sec  56.7 MBytes   475 Mbits/sec
[  5]   1.00-2.00   sec  43.7 MBytes   367 Mbits/sec
[  5]   2.00-3.00   sec  46.3 MBytes   388 Mbits/sec
[  5]   3.00-4.00   sec  39.3 MBytes   330 Mbits/sec
[  5]   4.00-5.00   sec  45.2 MBytes   379 Mbits/sec
[  5]   5.00-6.00   sec  38.3 MBytes   321 Mbits/sec
[  5]   6.00-7.00   sec  41.4 MBytes   347 Mbits/sec
[  5]   7.00-8.00   sec  38.0 MBytes   319 Mbits/sec
[  5]   8.00-9.00   sec  42.0 MBytes   353 Mbits/sec
[  5]   9.00-10.00  sec  46.4 MBytes   389 Mbits/sec
[  5]  10.00-10.05  sec  2.29 MBytes   404 Mbits/sec
- - - - - - - - - - - - - - - - - - - - - - - - -
[ ID] Interval           Transfer     Bitrate
[  5]   0.00-10.05  sec   440 MBytes   367 Mbits/sec                  receiver
-----------------------------------------------------------
Server listening on 5201
-----------------------------------------------------------

But as the client not bad for a Arm board

[rock@rockpi4 ~]$ iperf3 -c 192.168.1.12
Connecting to host 192.168.1.12, port 5201
[  5] local 192.168.1.9 port 38240 connected to 192.168.1.12 port 5201
[ ID] Interval           Transfer     Bitrate         Retr  Cwnd
[  5]   0.00-1.00   sec   186 MBytes  1.55 Gbits/sec    0    220 KBytes
[  5]   1.00-2.00   sec   190 MBytes  1.60 Gbits/sec   10    212 KBytes
[  5]   2.00-3.00   sec   215 MBytes  1.80 Gbits/sec    0    212 KBytes
[  5]   3.00-4.01   sec   208 MBytes  1.74 Gbits/sec   10    245 KBytes
[  5]   4.01-5.00   sec   180 MBytes  1.52 Gbits/sec   30    212 KBytes
[  5]   5.00-6.00   sec   197 MBytes  1.65 Gbits/sec   10    214 KBytes
[  5]   6.00-7.01   sec   161 MBytes  1.34 Gbits/sec    0    214 KBytes
[  5]   7.01-8.00   sec   137 MBytes  1.15 Gbits/sec   30    214 KBytes
[  5]   8.00-9.01   sec   138 MBytes  1.15 Gbits/sec   20    217 KBytes
[  5]   9.01-10.00  sec   159 MBytes  1.34 Gbits/sec    0    217 KBytes
- - - - - - - - - - - - - - - - - - - - - - - - -
[ ID] Interval           Transfer     Bitrate         Retr
[  5]   0.00-10.00  sec  1.73 GBytes  1.48 Gbits/sec  110             sender
[  5]   0.00-10.00  sec  1.73 GBytes  1.48 Gbits/sec                  receiver

iperf Done.

Same adapters on Manjaro X86 5.1 as server

Accepted connection from 192.168.1.9, port 41180
[  5] local 192.168.1.12 port 5201 connected to 192.168.1.9 port 41182
[ ID] Interval           Transfer     Bitrate
[  5]   0.00-1.00   sec   251 MBytes  2.11 Gbits/sec                  
[  5]   1.00-2.00   sec   281 MBytes  2.35 Gbits/sec                  
[  5]   2.00-3.00   sec   281 MBytes  2.35 Gbits/sec                  
[  5]   3.00-4.00   sec   281 MBytes  2.35 Gbits/sec                  
[  5]   4.00-5.00   sec   281 MBytes  2.35 Gbits/sec                  
[  5]   5.00-6.00   sec   281 MBytes  2.35 Gbits/sec                  
[  5]   6.00-7.00   sec   281 MBytes  2.35 Gbits/sec                  
[  5]   7.00-8.00   sec   281 MBytes  2.35 Gbits/sec                  
[  5]   8.00-9.00   sec   281 MBytes  2.35 Gbits/sec                  
[  5]   9.00-10.00  sec   281 MBytes  2.35 Gbits/sec                  
[  5]  10.00-10.04  sec  11.7 MBytes  2.35 Gbits/sec                  
- - - - - - - - - - - - - - - - - - - - - - - - -
[ ID] Interval           Transfer     Bitrate
[  5]   0.00-10.04  sec  2.72 GBytes  2.33 Gbits/sec                  receiver
-----------------------------------------------------------
Server listening on 5201

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