6sn7
Posts: 8
Joined: Sun Mar 11, 2018 7:11 pm

Rpi4 Ethernet Link Goes Down/Up

Mon Sep 09, 2019 10:27 am

Hi All,

I have a Raspberry Pi 4 running Raspian 10. Cat6 cable to a 1GbE switch.
During data transfers to/from the system, the ethernet link sporadically goes down then up.
Does anyone know of a fix for this? I have Rpi3 systems with no network issues.

Below is the logs in /var/log/messages.
kernel: [ 1784.822465] bcmgenet fd580000.genet eth0: Link is Down
kernel: [ 1787.942549] bcmgenet fd580000.genet eth0: Link is Up - 1Gbps/Full - flow control rx/tx
Thanks.

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RaTTuS
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Re: Rpi4 Ethernet Link Goes Down/Up

Mon Sep 09, 2019 10:40 am

dodgy power ?
dodgy NIC lead
dodgy NIC socket [either end]
dodgy PI

test by swapping components
How To ask Questions :- http://www.catb.org/esr/faqs/smart-questions.html
WARNING - some parts of this post may be erroneous YMMV

1QC43qbL5FySu2Pi51vGqKqxy3UiJgukSX
Covfefe

6sn7
Posts: 8
Joined: Sun Mar 11, 2018 7:11 pm

Re: Rpi4 Ethernet Link Goes Down/Up

Tue Sep 10, 2019 12:19 am

Thanks.
I swapped cables and tried different ports on the switch.
Something is funny with my gigabit switch. Other systems work okay. Just the rpi4 has issues.
When I plug the rpi4 into a 100Mb/s switch, all works fine.

ejolson
Posts: 3820
Joined: Tue Mar 18, 2014 11:47 am

Re: Rpi4 Ethernet Link Goes Down/Up

Tue Sep 10, 2019 12:41 am

6sn7 wrote:
Tue Sep 10, 2019 12:19 am
Thanks.
I swapped cables and tried different ports on the switch.
Something is funny with my gigabit switch. Other systems work okay. Just the rpi4 has issues.
When I plug the rpi4 into a 100Mb/s switch, all works fine.
Note that gigabit networking takes more than twice the electricity as 100 Mbit Ethernet. Therefore, you have not fully ruled out the consequences of an inadequate power supply.

What brand of switch are you using?

Would you by chance be using a Rosewill gigabit switch?

My Pi 4B does not work with the Rosewill RC-416 switch. It is now working well with a TP-LINK TL-SG108. More information can be found in

https://www.raspberrypi.org/forums/view ... 1#p1525396

6sn7
Posts: 8
Joined: Sun Mar 11, 2018 7:11 pm

Re: Rpi4 Ethernet Link Goes Down/Up

Tue Sep 10, 2019 6:17 pm

The power supply is rated at 3.0Amps. I put a scope on it and it shows a solid 5.2vdc with negligible ripple.
The GbE switch is a TRENDnet 8-port Gigabit GREENnet TEG-S80g.

The only other devices attached to the Pi4 is a 7 port USB3.0 hub with its own power supply.
I have 4 USB flash drives RAID-10 which I'm copying files to/from. When connected to a 1GbE switch, I copied 80+ GB of data to it without any issues.
I tried setting the link speed to 100Mb but got a lot of errors, so just staying connected to a 100Mb switch for now.

The CPU temp BTW stays at around 50c (heat sinks on the CPU, Mem and USB chips + cooling fan in the case).

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