Interface goes up and down continously

Hi there,
I'm running OpenWrt on my old Laptop. Lately my intergrated NIC (Realtek Chip, Driver = Generic FE-GE Realtek PHY r8169) is going down and up again. This occurs multiple times and to me it seems to occur randomely. Sometimes the link speed is even stepped down to 100Mbps/Full - flow control rx/tx instead of 1Gbps. Is my NIC dying or how can I fix this?

Thank you for your time!

relevant Kernel Log:

[   10.666527] r8169 0000:07:00.0 eth0: No native access to PCI extended config space, falling back to CSI
[   10.670613] r8169 0000:07:00.0 eth0: Link is Down
[   10.675002] br-lan: port 1(eth0) entered blocking state
[   10.676624] br-lan: port 1(eth0) entered disabled state
[   10.678409] device eth0 entered promiscuous mode
[   13.217428] r8169 0000:07:00.0 eth0: Link is Up - 1Gbps/Full - flow control rx/tx
[   13.220255] br-lan: port 1(eth0) entered blocking state
[   13.222956] br-lan: port 1(eth0) entered forwarding state
[   13.224492] IPv6: ADDRCONF(NETDEV_CHANGE): br-lan: link becomes ready
[   13.306335] IPv6: ADDRCONF(NETDEV_CHANGE): eth1: link becomes ready
[   13.308110] IPv6: ADDRCONF(NETDEV_CHANGE): eth1.10: link becomes ready
[   13.309436] r8152 3-1:1.0 eth1: carrier on
[  184.838769] r8169 0000:07:00.0 eth0: Link is Down
[  184.841551] br-lan: port 1(eth0) entered disabled state
[  185.862093] device eth0 left promiscuous mode
[  185.865087] br-lan: port 1(eth0) entered disabled state
[  186.009816] Generic FE-GE Realtek PHY r8169-0-700:00: attached PHY driver [Generic FE-GE Realtek PHY] (mii_bus:phy_addr=r8169-0-700:00, irq=IGNORE)
[  186.132979] r8169 0000:07:00.0 eth0: Link is Down
[  186.137523] br-lan: port 1(eth0) entered blocking state
[  186.138799] br-lan: port 1(eth0) entered disabled state
[  186.139958] device eth0 entered promiscuous mode
[  188.818586] r8169 0000:07:00.0 eth0: Link is Up - 1Gbps/Full - flow control rx/tx
[  188.821528] br-lan: port 1(eth0) entered blocking state
[  188.823852] br-lan: port 1(eth0) entered forwarding state
[  188.826446] IPv6: ADDRCONF(NETDEV_CHANGE): br-lan: link becomes ready
[  276.992238] r8169 0000:07:00.0 eth0: Link is Down
[  276.995141] br-lan: port 1(eth0) entered disabled state
[  278.020843] device eth0 left promiscuous mode
[  278.024170] br-lan: port 1(eth0) entered disabled state
[  278.151152] Generic FE-GE Realtek PHY r8169-0-700:00: attached PHY driver [Generic FE-GE Realtek PHY] (mii_bus:phy_addr=r8169-0-700:00, irq=IGNORE)
[  278.275175] r8169 0000:07:00.0 eth0: Link is Down
[  278.278079] br-lan: port 1(eth0) entered blocking state
[  278.280136] br-lan: port 1(eth0) entered disabled state
[  278.282387] device eth0 entered promiscuous mode
[  284.126877] r8169 0000:07:00.0 eth0: Link is Up - 1Gbps/Full - flow control rx/tx
[  284.130051] br-lan: port 1(eth0) entered blocking state
[  284.133063] br-lan: port 1(eth0) entered forwarding state
[  284.136289] IPv6: ADDRCONF(NETDEV_CHANGE): br-lan: link becomes ready
[  285.596298] r8169 0000:07:00.0 eth0: Link is Down
[  285.599335] br-lan: port 1(eth0) entered disabled state
[  286.627879] device eth0 left promiscuous mode
[  286.632136] br-lan: port 1(eth0) entered disabled state
[  286.777232] Generic FE-GE Realtek PHY r8169-0-700:00: attached PHY driver [Generic FE-GE Realtek PHY] (mii_bus:phy_addr=r8169-0-700:00, irq=IGNORE)
[  286.897050] r8169 0000:07:00.0 eth0: Link is Down
[  286.901261] br-lan: port 1(eth0) entered blocking state
[  286.903327] br-lan: port 1(eth0) entered disabled state
[  286.905578] device eth0 entered promiscuous mode
[  292.671404] r8169 0000:07:00.0 eth0: Link is Up - 1Gbps/Full - flow control rx/tx
[  292.674429] br-lan: port 1(eth0) entered blocking state
[  292.676721] br-lan: port 1(eth0) entered forwarding state
[  292.679254] IPv6: ADDRCONF(NETDEV_CHANGE): br-lan: link becomes ready
[  293.818243] r8169 0000:07:00.0 eth0: Link is Down
[  293.819174] br-lan: port 1(eth0) entered disabled state
[  294.848397] device eth0 left promiscuous mode
[  294.850237] br-lan: port 1(eth0) entered disabled state
[  294.975584] Generic FE-GE Realtek PHY r8169-0-700:00: attached PHY driver [Generic FE-GE Realtek PHY] (mii_bus:phy_addr=r8169-0-700:00, irq=IGNORE)
[  295.095141] r8169 0000:07:00.0 eth0: Link is Down
[  295.098125] br-lan: port 1(eth0) entered blocking state
[  295.100204] br-lan: port 1(eth0) entered disabled state
[  295.102466] device eth0 entered promiscuous mode
[  300.019334] r8169 0000:07:00.0 eth0: Link is Up - 100Mbps/Full - flow control rx/tx
[  300.022530] br-lan: port 1(eth0) entered blocking state
[  300.025557] br-lan: port 1(eth0) entered forwarding state
[  300.027114] IPv6: ADDRCONF(NETDEV_CHANGE): br-lan: link becomes ready

And relevant System Log:

Mon Mar  7 17:38:32 2022 kern.info kernel: [  285.596298] r8169 0000:07:00.0 eth0: Link is Down
Mon Mar  7 17:38:32 2022 kern.info kernel: [  285.599335] br-lan: port 1(eth0) entered disabled state
Mon Mar  7 17:38:32 2022 daemon.notice netifd: Network device 'eth0' link is down
Mon Mar  7 17:38:33 2022 daemon.notice netifd: bridge 'br-lan' link is down
Mon Mar  7 17:38:33 2022 daemon.notice netifd: Interface 'lan' has link connectivity loss
Mon Mar  7 17:38:33 2022 daemon.notice netifd: Interface 'lan' is now down

I'd start by checking cables. You could have a marginal cable currently in use.

Another thing to try would be to insert a gigabit switch between your devices and look to see which side of the connection is having difficulty. Any unmanaged switch will do the trick, but if you happen to have a managed switch, you may also be able to get logging and such to see what it is seeing).

2 Likes

Yeah, or it could be an Energy Efficient Ethernet (EEE) compatibility issue.

3 Likes

Thank you for your suggestions. I changed the cable and so far it seems to work, but only time will tell. I will keep you updated.

I never thought that it would be the cable, but I think it was really a faulty cat 6 cable from the ISP! Thank you @psherman! (Interface is up ever since I changed the cable)

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