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Reestablish network connection after the ETH cable replugged in
Posted: 02 Nov 2020, 08:17
by hikaru2001
Hello guys,
After I plug out the ethernet cable from RevPi Core3 and plug it in again. The ethernet connection won't be reestablished. My laptop can't ping RevPi Core 3 again until I power on RevPi Core 3 again.
Is that normal? How can I do some settings in order to make RevPi Core3 restart ethernet connection automatically?
Thank you so much!
Re: Reestablish network connection after the ETH cable replugged in
Posted: 02 Nov 2020, 17:04
by dirk
Hello hikaru2001, I need more information. Can you send me a sos report?
Code: Select all
sudo apt update
sudo apt install revpi-tools
revpi-sos
It works like so:
Code: Select all
pi@RevPi40302:~ $ revpi-sos
The report will be generated under folder /tmp in a .tar.xz file, which
can be extracted with command: tar -Jxvf xxx.tar.xz in linux or 7zip in Windows.
And then some inspection can be done before it is sent to support@kunbus.com.
Are you going to continue (N/y)?y
report generating...
Your report has been generated and saved in:
/tmp/sosreport-RevPi40302-20201102163308.tar.xz
To make the report have better accessibility, the ownership of the report
can be changed to the current user.
Are you going to proceed(N/y)?y
The ownership of /tmp/sosreport-RevPi40302-20201102163308.tar.xz has been changed to user:pi
Please have in mind that you agree to send us private data i.e. IP address.
Send the report to
support@kunbus.com
Re: Reestablish network connection after the ETH cable replugged in
Posted: 03 Nov 2020, 03:16
by hikaru2001
Hi Dirk,
I have sent you the SOS report by email.
Today I try "sudo ip link set eth0 down && sudo ip link set eth0 up" and find that the connection-reestablish problem can be solved. The network connection will be rebuilt whenever the ethernet cable is plugged out and in again after that command is executed.
Re: Reestablish network connection after the ETH cable replugged in
Posted: 03 Nov 2020, 15:28
by dirk
Hi, we have received the sos-report with thanks, discussed it in the RevPi Stand Up and roughly analyzed it:
We noticed the following things in the Kern.log shortly before the eth0 connection is restarted:
There are messages from the USB power management: "eth0: hardware isn't capable of remote wakeup".
One or more Logitech USB HID devices report "HID++ 2.0 device connected".
These are only rough hits but can be a good start for troubleshooting.
The command you describe and the solution is not quite clear to us.
Is it enough to enter the command only once after a connection loss and then not anymore?
Or every time the connection is lost.
Re: Reestablish network connection after the ETH cable replugged in
Posted: 06 Nov 2020, 09:09
by hikaru2001
Hi Dirk,
The command is only entered once, then the connection will always recover automatically after the cable is plugged out and in again.
Re: Reestablish network connection after the ETH cable replugged in
Posted: 10 Nov 2020, 15:37
by dirk
Hi hikaru2001, this is interesting that you have to enter the command only once.
Is the command entered on the RevPi or on the laptop? So you need a HDMI and a USB Keyboard as you don't have SSH access to the RevPi.
Call ethtool if there is no more link and see if a physical link is displayed?
We have to reproduce the error so that we can understand what caused it.
Re: Reestablish network connection after the ETH cable replugged in
Posted: 12 Nov 2020, 05:30
by hikaru2001
Hi Dirk,
Sure the command is entered on RevPi!
After the error is reproduced, I call ethtool and the result is "Link deteted: yes", "Auto-negotiation: on".
Re: Reestablish network connection after the ETH cable replugged in
Posted: 12 Nov 2020, 15:26
by dirk
Hi hikaru2001, please try the following:
- Power cycle the RevPi
- start a Wireshark capture on your Laptop
- run the command on your RevPi "sudo tcpdump -i eth0 -C /tmp/capture.pcap"
- pull the Ehternet cable and plug it again after a few seconds
- ping the RevPi from your laptop - it should not be possible
- stop and save the Wireshark capture on the laptop
- cancel the tcpdump on the RevPi
- run the command on your RevPi "ethtool -S eth0" to give out the error couters and other statistics and make a screenshot.
Send us everything.
Hopefully we'll see things clear then. Thank you for your work.
Re: Reestablish network connection after the ETH cable replugged in
Posted: 26 Nov 2020, 17:06
by dirk
Hi hikaru2001, do you have updates for me? Is this issue still open?
Re: Reestablish network connection after the ETH cable replugged in
Posted: 27 Nov 2020, 02:57
by hikaru2001
Hi Dirk,
Sorry for my late reply! On some day of the second last week, the reestablish network connection problem didn't exist while I hadn't done anything to RevPi Core3. I want to simulate the error again for a long time, but not realized.
Maybe the issue can be closed. Thank you!