Note To Future Self: Lenovo Laptop USB-C Mini Dock Reset

Hello Future Self,

Past Self here leaving you a note since I forgot to do so last time.

The Problem

When running Linux on a Lenovo, there are times where a firmware update will cause problems with the USB-C Mini Dock afterwards. In the previous 2 cases, the USB-C's RTL network will no longer show up as a seen device. External monitors plugged into the dock may also not function correctly, but it only happened once so I am not sure about that.

Diagnosis of the problem is that the system will complain of no internet connection, and commands will show something like the following (output altered):

ssmoogen@ssmoogen-rh:~$ ip addr
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 scope host lo
       valid_lft forever preferred_lft forever
    inet6 ::1/128 scope host 
       valid_lft forever preferred_lft forever
2: enp0s31f6: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc fq_codel state DOWN group default qlen 1000
    link/ether ab:cd:12:34:56:78 brd ff:ff:ff:ff:ff:ff
3: wlp82s0: <BROADCAST,MULTICAST> mtu 1500 qdisc noqueue state DOWN group default qlen 1000
    link/ether 9a:bc:de:f1:23:45 brd ff:ff:ff:ff:ff:ff permaddr aa:aa:bb:bb:cc:cc

The part that has confused me at least once before is that the enp0s31f6 says NO-CARRIER which made me believe that the switch had problems. Looking at the USB-C showed that the link light was on and there was traffic. This led me to try various solutions which were wrong.

Attempted Solutions

In trying to diagnosis this in the past, I tried backing out all the firmware updates to see if they would untrigger the bricking of the connection. The fwupdtool worked great to do this, and I was able to back down through 8 firmwares without a hitch. However the network still said it was offline.

Next I went through older kernels and tried booting with a USB stick. All of them continued to show the e1000e as disconnected. Finally I went through the journalctl command to look for previous boots and what networks were shown up.

ssmoogen@ssmoogen-rh:~$ journalctl | grep eth0 | tail -n 100
....
Apr 20 16:54:37 ssmoogen-rh.localdomain kernel: e1000e 0000:00:1f.6 eth0: Intel(R) PRO/1000 Network Connection
Apr 20 16:54:37 ssmoogen-rh.localdomain kernel: e1000e 0000:00:1f.6 eth0: MAC: 13, PHY: 12, PBA No: FFFFFF-0FF
Apr 20 16:54:37 ssmoogen-rh.localdomain kernel: e1000e 0000:00:1f.6 enp0s31f6: renamed from eth0
Apr 20 16:54:38 ssmoogen-rh.localdomain kernel: r8152 4-2.1.2:1.0 eth0: v1.12.13
Apr 20 16:54:38 ssmoogen-rh.localdomain kernel: r8152 4-2.1.2:1.0 enp9s0u2u1u2: renamed from eth0
Apr 20 17:09:24 ssmoogen-rh.localdomain kernel: e1000e 0000:00:1f.6 eth0: (PCI Express:2.5GT/s:Width x1) aa:aa:aa:bb:bb:bb
Apr 20 17:09:24 ssmoogen-rh.localdomain kernel: e1000e 0000:00:1f.6 eth0: Intel(R) PRO/1000 Network Connection
Apr 20 17:09:24 ssmoogen-rh.localdomain kernel: e1000e 0000:00:1f.6 eth0: MAC: 13, PHY: 12, PBA No: FFFFFF-0FF
Apr 20 17:09:24 ssmoogen-rh.localdomain kernel: e1000e 0000:00:1f.6 enp0s31f6: renamed from eth0
Apr 20 17:13:56 ssmoogen-rh.localdomain kernel: e1000e 0000:00:1f.6 eth0: (PCI Express:2.5GT/s:Width x1) aa:aa:aa:bb:bb:bb
Apr 20 17:13:56 ssmoogen-rh.localdomain kernel: e1000e 0000:00:1f.6 eth0: Intel(R) PRO/1000 Network Connection
Apr 20 17:13:56 ssmoogen-rh.localdomain kernel: e1000e 0000:00:1f.6 eth0: MAC: 13, PHY: 12, PBA No: FFFFFF-0FF
Apr 20 17:13:56 ssmoogen-rh.localdomain kernel: e1000e 0000:00:1f.6 enp0s31f6: renamed from eth0
...

The Solution

Matching up the timestamps I see that there was an additional device see before the updates occurred. This was using the r8152 driver but after the firmware updates it no longer showed up. This finally triggered a memory of an email I had seen where someone else had a similar problem. Going through my email archives, I found that the solution they had found was to unplug the USB-C Dock for 1 minute and then plug everything back in. Sure enough, doing this restored the RTL driver and my network was restored. The e1000 was a red herring as it is somewhere internal to the laptop and probably available through a dongle which I forgot about as there doesn't seem to be a RJ-45 jack I could find on the exterior of the laptop.

Anyway, when this happens again, please remember this letter and save yourself 2 hours of firmware resets and kernel reboots. Sometimes completely turning off the hardware (remove all power from the Dock including the laptop) and turning it back on WILL fix the problem.