Comment 0 for bug 1832472

Upon plugging in a USB adapter for NBase-T ethernet with an Realtek chip RTL8156 the kernel module cdc_ncm starts flooding /var/log/syslog with unneccessary status info.

The status lines either say that there's no ethernet link or show the interface as connected and state the link speed.

The relevant parts from /var/log/syslog after attaching the adapter without ethernet link read like this:

[...]
Jun 12 10:48:58 resdz-v13 kernel: [ 4240.398485] usb 2-3: new SuperSpeed Gen 1 USB device number 5 using xhci_hcd
Jun 12 10:48:58 resdz-v13 kernel: [ 4240.419463] usb 2-3: New USB device found, idVendor=0bda, idProduct=8156, bcdDevice=30.00
Jun 12 10:48:58 resdz-v13 kernel: [ 4240.419469] usb 2-3: New USB device strings: Mfr=1, Product=2, SerialNumber=6
Jun 12 10:48:58 resdz-v13 kernel: [ 4240.419472] usb 2-3: Product: USB 10/100/1G/2.5G LAN
Jun 12 10:48:58 resdz-v13 kernel: [ 4240.419475] usb 2-3: Manufacturer: Realtek
Jun 12 10:48:58 resdz-v13 kernel: [ 4240.419477] usb 2-3: SerialNumber: 000000001
Jun 12 10:48:58 resdz-v13 kernel: [ 4240.447769] cdc_ncm 2-3:2.0: MAC-Address: 00:13:3b:68:00:e9
Jun 12 10:48:58 resdz-v13 kernel: [ 4240.447775] cdc_ncm 2-3:2.0: setting rx_max = 16384
Jun 12 10:48:58 resdz-v13 kernel: [ 4240.447929] cdc_ncm 2-3:2.0: setting tx_max = 16384
Jun 12 10:48:58 resdz-v13 kernel: [ 4240.448901] cdc_ncm 2-3:2.0 usb0: register 'cdc_ncm' at usb-0000:00:14.0-3, CDC NCM, 00:13:3b:68:00:e9
Jun 12 10:48:58 resdz-v13 NetworkManager[916]: <info> [1560329338.1872] manager: (usb0): new Ethernet device (/org/freedesktop/NetworkManager/Devices/8)
Jun 12 10:48:58 resdz-v13 mtp-probe: checking bus 2, device 5: "/sys/devices/pci0000:00/0000:00:14.0/usb2/2-3"
Jun 12 10:48:58 resdz-v13 mtp-probe: bus: 2, device: 5 was not an MTP device
Jun 12 10:48:58 resdz-v13 systemd-udevd[4299]: Using default interface naming scheme 'v240'.
Jun 12 10:48:58 resdz-v13 systemd-udevd[4299]: link_config: autonegotiation is unset or enabled, the speed and duplex are not writable.
Jun 12 10:48:58 resdz-v13 kernel: [ 4240.466476] cdc_ncm 2-3:2.0 enx00133b6800e9: renamed from usb0
Jun 12 10:48:58 resdz-v13 NetworkManager[916]: <info> [1560329338.2315] device (usb0): interface index 7 renamed iface from 'usb0' to 'enx00133b6800e9'
Jun 12 10:48:58 resdz-v13 systemd-udevd[4299]: Process 'vlan-network-interface UDEV' failed with exit code 1.
Jun 12 10:48:58 resdz-v13 NetworkManager[916]: <info> [1560329338.2431] device (enx00133b6800e9): state change: unmanaged -> unavailable (reason 'managed', sys-iface-state: 'external')
Jun 12 10:48:58 resdz-v13 charon: 12[KNL] interface enx00133b6800e9 activated
Jun 12 10:48:58 resdz-v13 mtp-probe: checking bus 2, device 5: "/sys/devices/pci0000:00/0000:00:14.0/usb2/2-3"
Jun 12 10:48:58 resdz-v13 mtp-probe: bus: 2, device: 5 was not an MTP device
Jun 12 10:48:58 resdz-v13 kernel: [ 4240.524052] cdc_ncm 2-3:2.0 enx00133b6800e9: network connection: disconnected
Jun 12 10:48:58 resdz-v13 kernel: [ 4240.556109] cdc_ncm 2-3:2.0 enx00133b6800e9: network connection: disconnected
Jun 12 10:48:58 resdz-v13 kernel: [ 4240.588054] cdc_ncm 2-3:2.0 enx00133b6800e9: network connection: disconnected
Jun 12 10:48:58 resdz-v13 kernel: [ 4240.620383] cdc_ncm 2-3:2.0 enx00133b6800e9: network connection: disconnected
Jun 12 10:48:58 resdz-v13 kernel: [ 4240.652415] cdc_ncm 2-3:2.0 enx00133b6800e9: network connection: disconnected
[...]

Upon plugging in the ethernet cable I see
[...]
Jun 12 10:49:01 resdz-v13 kernel: [ 4243.372273] cdc_ncm 2-3:2.0 enx00133b6800e9: 1000 mbit/s downlink 1000 mbit/s uplink
Jun 12 10:49:01 resdz-v13 kernel: [ 4243.404278] cdc_ncm 2-3:2.0 enx00133b6800e9: network connection: connected
[...]
and Network Manager starts its work.

After the interface is up the flooding continues:
[...]
Jun 12 10:49:01 resdz-v13 kernel: [ 4243.564056] cdc_ncm 2-3:2.0 enx00133b6800e9: 1000 mbit/s downlink 1000 mbit/s uplink
Jun 12 10:49:01 resdz-v13 kernel: [ 4243.596051] cdc_ncm 2-3:2.0 enx00133b6800e9: network connection: connected
Jun 12 10:49:01 resdz-v13 whoopsie[1530]: [10:49:01] The default IPv4 route is: /org/freedesktop/NetworkManager/ActiveConnection/4
Jun 12 10:49:01 resdz-v13 whoopsie[1530]: [10:49:01] Not a paid data plan: /org/freedesktop/NetworkManager/ActiveConnection/4
Jun 12 10:49:01 resdz-v13 whoopsie[1530]: [10:49:01] Found usable connection: /org/freedesktop/NetworkManager/ActiveConnection/4
Jun 12 10:49:01 resdz-v13 whoopsie[1530]: [10:49:01] online
Jun 12 10:49:01 resdz-v13 kernel: [ 4243.628055] cdc_ncm 2-3:2.0 enx00133b6800e9: 1000 mbit/s downlink 1000 mbit/s uplink
Jun 12 10:49:01 resdz-v13 kernel: [ 4243.660060] cdc_ncm 2-3:2.0 enx00133b6800e9: network connection: connected
Jun 12 10:49:01 resdz-v13 kernel: [ 4243.692055] cdc_ncm 2-3:2.0 enx00133b6800e9: 1000 mbit/s downlink 1000 mbit/s uplink
Jun 12 10:49:01 resdz-v13 kernel: [ 4243.724054] cdc_ncm 2-3:2.0 enx00133b6800e9: network connection: connected
Jun 12 10:49:01 resdz-v13 kernel: [ 4243.756060] cdc_ncm 2-3:2.0 enx00133b6800e9: 1000 mbit/s downlink 1000 mbit/s uplink
Jun 12 10:49:01 resdz-v13 kernel: [ 4243.788053] cdc_ncm 2-3:2.0 enx00133b6800e9: network connection: connected
Jun 12 10:49:01 resdz-v13 kernel: [ 4243.820056] cdc_ncm 2-3:2.0 enx00133b6800e9: 1000 mbit/s downlink 1000 mbit/s uplink
Jun 12 10:49:01 resdz-v13 nm-dispatcher: req:2 'connectivity-change': start running ordered scripts...
Jun 12 10:49:01 resdz-v13 kernel: [ 4243.852060] cdc_ncm 2-3:2.0 enx00133b6800e9: network connection: connected
Jun 12 10:49:01 resdz-v13 kernel: [ 4243.884064] cdc_ncm 2-3:2.0 enx00133b6800e9: 1000 mbit/s downlink 1000 mbit/s uplink
Jun 12 10:49:01 resdz-v13 kernel: [ 4243.916054] cdc_ncm 2-3:2.0 enx00133b6800e9: network connection: connected
Jun 12 10:49:01 resdz-v13 kernel: [ 4243.948055] cdc_ncm 2-3:2.0 enx00133b6800e9: 1000 mbit/s downlink 1000 mbit/s uplink
Jun 12 10:49:01 resdz-v13 kernel: [ 4243.980049] cdc_ncm 2-3:2.0 enx00133b6800e9: network connection: connected
Jun 12 10:49:01 resdz-v13 kernel: [ 4244.012056] cdc_ncm 2-3:2.0 enx00133b6800e9: 1000 mbit/s downlink 1000 mbit/s uplink
Jun 12 10:49:01 resdz-v13 kernel: [ 4244.044053] cdc_ncm 2-3:2.0 enx00133b6800e9: network connection: connected
[...]

Expected behavior is showing the status lines only once after link status changes.

Kernel version is: 5.0.0-16-generic, OS: Kubuntu 19.04

Module info for cdc_ncm:

filename: /lib/modules/5.0.0-16-generic/kernel/drivers/net/usb/cdc_ncm.ko
license: Dual BSD/GPL
description: USB CDC NCM host driver
author: Hans Petter Selasky
srcversion: 9CC08FECEC9EC4AF1DBA207
alias: usb:v*p*d*dc*dsc*dp*ic02isc0Dip00in*
alias: usb:v1546p1010d*dc*dsc*dp*ic02isc0Dip00in*
alias: usb:v1519p0443d*dc*dsc*dp*ic02isc0Dip00in*
alias: usb:v12D1p*d*dc*dsc*dp*ic02isc0Dip00in*
alias: usb:v0930p*d*dc*dsc*dp*ic02isc0Dip00in*
alias: usb:v413Cp*d*dc*dsc*dp*ic02isc0Dip00in*
alias: usb:v413Cp81BCd*dc*dsc*dp*ic02isc0Dip00in*
alias: usb:v413Cp81BBd*dc*dsc*dp*ic02isc0Dip00in*
alias: usb:v1BC7p0036d*dc*dsc*dp*ic02isc0Dip00in*
alias: usb:v0BDBp*d*dc*dsc*dp*ic02isc0Dip00in*
depends: usbnet
retpoline: Y
intree: Y
name: cdc_ncm
vermagic: 5.0.0-16-generic SMP mod_unload
sig_id: PKCS#7
signer:
sig_key:
sig_hashalgo: md4
signature: 30:82:02:A5:06:09:2A:86:48:86:F7:0D:01:07:02:A0:82:02:96:30:
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parm: prefer_mbim:Prefer MBIM setting on dual NCM/MBIM functions (bool)