Network Manager keeps disconnecting

morgan · April 4, 2021, 11:20am

Hello,

I’m running a fresh install of Debian Bullseye (I also had the same result with Buster) on the Librem Mini v1. The Network Manager keeps disconnecting and reconnecting the ethernet randomly, it doesn’t seem to be occurring at a regular interval.

Any ideas?

morgan · April 4, 2021, 9:35pm

I disabled Network Manager and switched to Connman and the result is the same, so it’s not an issue with the app…

irvinewade · April 5, 2021, 6:57am

Does it happen with PureOS (for testing purposes) or another distro (e.g. Ubuntu)?

How long is it disconnected for? Enough time for troubleshooting or no chance?

Usual fault isolation … try another cable? try another port on the switch?

What is the device at the other end? (Is it a switch? A managed switch? A router?) Any logging at that end?

morgan · April 5, 2021, 12:35pm

I justed tested with Linux Mint and same issue.

The disconnection lasts only a few seconds. I noticed that each time it reconnects it makes a brand new connection - for example if I open Network Connections and change the name and some of the settings of the wired connection, after it does its next disconnect/reconnect cycle all of my changes are gone.

The cable is good, I’ve been using it on another machine for a year or so, that machine is right next to the Mini and I’ve been able to quickly take it from one to the other to test it. No issues in the other machine, running the same OS.

The cable is connected to a Virgin Hub 3 router. It offers no logs at all as far as I can see.

morgan · April 5, 2021, 5:51pm

Here’s some of the dmesg log

[Mon Apr  5 17:00:20 2021] r8169 0000:01:00.0 eno0: Link is Down
[Mon Apr  5 17:00:34 2021] r8169 0000:01:00.0 eno0: Link is Up - 100Mbps/Full - flow control rx/tx
[Mon Apr  5 17:09:25 2021] r8169 0000:01:00.0 eno0: Link is Down
[Mon Apr  5 17:09:39 2021] r8169 0000:01:00.0 eno0: Link is Up - 100Mbps/Full - flow control rx/tx
[Mon Apr  5 17:10:42 2021] r8169 0000:01:00.0 eno0: Link is Down
[Mon Apr  5 17:10:56 2021] r8169 0000:01:00.0 eno0: Link is Up - 100Mbps/Full - flow control rx/tx
[Mon Apr  5 17:15:00 2021] r8169 0000:01:00.0 eno0: Link is Down
[Mon Apr  5 17:15:14 2021] r8169 0000:01:00.0 eno0: Link is Up - 100Mbps/Full - flow control rx/tx
[Mon Apr  5 17:19:49 2021] r8169 0000:01:00.0 eno0: Link is Down
[Mon Apr  5 17:20:03 2021] r8169 0000:01:00.0 eno0: Link is Up - 100Mbps/Full - flow control rx/tx
[Mon Apr  5 17:42:50 2021] r8169 0000:01:00.0 eno0: Link is Down
[Mon Apr  5 17:43:04 2021] r8169 0000:01:00.0 eno0: Link is Up - 100Mbps/Full - flow control rx/tx
[Mon Apr  5 17:49:42 2021] r8169 0000:01:00.0 eno0: Link is Down
[Mon Apr  5 17:49:56 2021] r8169 0000:01:00.0 eno0: Link is Up - 100Mbps/Full - flow control rx/tx
[Mon Apr  5 17:59:53 2021] r8169 0000:01:00.0 eno0: Link is Down
[Mon Apr  5 18:00:07 2021] r8169 0000:01:00.0 eno0: Link is Up - 100Mbps/Full - flow control rx/tx
[Mon Apr  5 18:12:48 2021] r8169 0000:01:00.0 eno0: Link is Down
[Mon Apr  5 18:13:02 2021] r8169 0000:01:00.0 eno0: Link is Up - 100Mbps/Full - flow control rx/tx
[Mon Apr  5 18:19:47 2021] r8169 0000:01:00.0 eno0: Link is Down
[Mon Apr  5 18:20:01 2021] r8169 0000:01:00.0 eno0: Link is Up - 100Mbps/Full - flow control rx/tx
[Mon Apr  5 18:20:47 2021] r8169 0000:01:00.0 eno0: Link is Down
[Mon Apr  5 18:21:01 2021] r8169 0000:01:00.0 eno0: Link is Up - 100Mbps/Full - flow control rx/tx
[Mon Apr  5 18:27:33 2021] r8169 0000:01:00.0 eno0: Link is Down
[Mon Apr  5 18:27:47 2021] r8169 0000:01:00.0 eno0: Link is Up - 100Mbps/Full - flow control rx/tx
[Mon Apr  5 18:30:00 2021] r8169 0000:01:00.0 eno0: Link is Down
[Mon Apr  5 18:30:14 2021] r8169 0000:01:00.0 eno0: Link is Up - 100Mbps/Full - flow control rx/tx
[Mon Apr  5 18:31:56 2021] r8169 0000:01:00.0 eno0: Link is Down
[Mon Apr  5 18:32:11 2021] r8169 0000:01:00.0 eno0: Link is Up - 100Mbps/Full - flow control rx/tx
[Mon Apr  5 18:33:16 2021] r8169 0000:01:00.0 eno0: Link is Down
[Mon Apr  5 18:33:31 2021] r8169 0000:01:00.0 eno0: Link is Up - 100Mbps/Full - flow control rx/tx
[Mon Apr  5 18:36:14 2021] r8169 0000:01:00.0 eno0: Link is Down
[Mon Apr  5 18:36:28 2021] r8169 0000:01:00.0 eno0: Link is Up - 100Mbps/Full - flow control rx/tx
[Mon Apr  5 18:39:56 2021] r8169 0000:01:00.0 eno0: Link is Down
[Mon Apr  5 18:40:10 2021] r8169 0000:01:00.0 eno0: Link is Up - 100Mbps/Full - flow control rx/tx
[Mon Apr  5 18:43:10 2021] r8169 0000:01:00.0 eno0: Link is Down
[Mon Apr  5 18:43:24 2021] r8169 0000:01:00.0 eno0: Link is Up - 100Mbps/Full - flow control rx/tx
[Mon Apr  5 18:45:31 2021] r8169 0000:01:00.0 eno0: Link is Down
[Mon Apr  5 18:45:45 2021] r8169 0000:01:00.0 eno0: Link is Up - 100Mbps/Full - flow control rx/tx
[Mon Apr  5 18:49:49 2021] r8169 0000:01:00.0 eno0: Link is Down
[Mon Apr  5 18:50:03 2021] r8169 0000:01:00.0 eno0: Link is Up - 100Mbps/Full - flow control rx/tx

morgan · April 5, 2021, 6:15pm

try another port on the switch?

I tried switching to a different port on the router and I think it might have resolved the issue. 20 minutes so far without a dropout. Strange how it doesn’t affect my other system though.

I also noticed dmesg says 1Gbps now instead of 100Mbps

[Mon Apr 5 18:56:11 2021] r8169 0000:01:00.0 eno0: Link is Up - 1Gbps/Full - flow control rx/tx

irvinewade · April 6, 2021, 12:09am

Yes, exactly.

It seems as if the Mini connected to the original port is coming up as Fast Ethernet (FE) (100 Mbit/s) and then either not trying to negotiate Gigabit Ethernet (GbE) (1000 Mbit/s) or failing to do so.

The fact that the cable and port works on another computer could indicate that the other computer expects only FE or that it is more tolerant of failure during the negotiation.

If you want to pursue this, I would still try to lay my hands on a known good GbE cable, just for fault isolation.

I have zero chance of getting hold of that router, hence can only guess, but things to look for would be:

does the router have one LED per ethernet port and the colour of the LED tells you whether you negotiated GbE or FE? (usually green for GbE and amber for FE or worse)
if so, what does the LED say when connected to the working computer?
does the router allow you to hard-code the ethernet settings and disable negotiation on a per-port basis? (if the router has this capability then you want not to be doing that unless you are connected to a very old device, and you know what you are doing, and you have to do this for it to work)
there are even routers around where some ports are “special” i.e. not all ports are created equal - but you would need to read the manual that came with the router

Maybe you are happy that you got it working …

morgan · April 6, 2021, 11:46am

Maybe you are happy that you got it working …

This

Thanks for your help!