Raspberry Pi eth0 instability due to EEE being enabled by default

Talk about Documentation
1

I recently installed OpenWrt on a Raspberry Pi 4, and I noticed that every few minutes the eth0 interface would go down, then come back up 2 seconds later, as indicated in the System Log. This leads to packet loss (e.g. websites sometimes take a long time to load) for devices connecting through that interface. The issue went away after I disabled EEE (Energy-Efficient Ethernet) for eth0 by running the following command, as well as adding it to /etc/rc.local (LuCI -> System -> Startup -> Local Startup) so that EEE stays disabled after a reboot:

ethtool --set-eee eth0 eee off

I think this should be noted in the Wiki article for the Raspberry Pi. If there is some way to configure EEE through UCI though, then that might be preferable over the ethtool command. Also, I'm not sure if this applies to the other models (e.g. Pi 3B, Pi 5) as I am currently only able to test this on a Pi 4.

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2

Purely anecdotal, but I have a Pi4 that runs 24/7 with OpenWrt and does not experience this issue. The port stays up without issue and I've never needed to use ethtool to set anything on that device.

3

Interesting. It could be due to a combination of the Pi 4 and the unmanaged (and therefore un-configurable) ethernet switch I have it connected to.

4

Yes, I was actually thinking it could be the result of the device on the other end.

Try a different switch or a direct connection to a computer as a test.

5

I swapped it out with a different unmanaged switch a few hours ago, and it's been working fine even with EEE enabled. I wonder if this sort of thing is even worth documenting on the wiki. Maybe just the existence of this thread is enough.

Strange DNS behavior with a particular machine connected to Raspberry Pi 4 router
6

Posting the name of the switch having issues would be even more helpful.

7

Hi Everyone,

Hope you are all well, I am having a somewhat similar issue and was hoping the fix posted by @daigennki would assist but it did not work for me, I am using a pi5 which requires a manual reboot to restore connection, issue described OpenWrt 25.12.0-rc5 - Release Candidate - #124 by 13en. open to any suggestions and sorry for hijacking the topic.

8

That seems unrelated, as it seems my issue was more to do with a compatibility issue between the Pi4 and a particular unmanaged switch when EEE is enabled on the Pi4. Not to mention my issue is on the latest stable release, 24.10.5, as opposed to one of the RCs.

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9

Sorry, forgot to reply to this.

The switch having issues is a somewhat old (about 10 years old) Buffalo LSW4-GT-5EP. It seems to have been long out of production and only sold in Japan. I have had some weird issues with various Buffalo products in the past, especially Wi-Fi routers, so I have been avoiding them for a while.

The one that works without issues is a Netgear GS605v5, which is a little over a year old.

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10

Glad that you identified the culprit.

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