Lenovo USB3 Dock Ethernet Not Working After Upgrading to 7.6

[jaredmny]

I was previously running 7.4M0 on a Lenovo X1 Carbon Touch with a Lenovo USB 3 Dock. Ran fine on Windows 8. After I upgraded to Win 8.1, I went to refresh all drivers, including attempting to upgrade to the latest DisplayLink version 7.7. However, I found that this caused the dock ethernet to not work... The link never came up in software and I can see the activity light on the network switch port that the dock is connected to turn on for about one second, then off for two, then back on. It just cycles like that indefinitely. I found that 7.6M2 performed the same, but that 7.5M2 seems to work fine.

Any thoughts on what might be happening and what might have changed between 7.5 and 7.6 to cause this?

Thanks.

[Wim]

Before 7.6 software, the Ethernet link would incorrectly auto negotoate unsupported half duplex speeds (eg if it was connected to a hub rather than a switch). The link lights would be on, but it would not have worked properly.

Now the link is correctly not connected in this state. You will be seeing the link coming up, trying to negotiate and not finding a matching speed, and disconnecting.

To solve this, connect the Ethernet of the dock to an Ethernet switch rather than a hub.

Wim

[jaredmny]

Wim -

The dock is connected to a GigE switch sitting next to the laptop using a 2 meter cable. When the link is working (using the older versions of the driver), the link speed shows 1.0 Gbps and works fine, even under high-stress iSCSI applications. So it doesn't seem like it is an auto-negotiation problem... Any other thoughts?

Thanks.

[Wim]

Could you post the logs as described here:

http://kb.displaylink.com/269

Wim

[jaredmny]

Sorry for the delay in getting back to you. I have sent you a PM with a link to the log files.

I generated the logs after uninstalling 7.5M2, rebooting, running the cleaner tool, rebooting, reinstalling with the latest 7.7M0.

I have tried replacing the cable between the dock and the switch but this didn't make any difference. I also tried disabling auto-negotiation and forcing the link to GigE on the dock driver, but this also didn't make any improvement.

Thank you for working through it with me.

[jaredmny]

Wim? Thoughts?

[Wim]

Hi

I've checked the logs and they do show what I expected. Every 3-4 seconds there is a message from the firmware:

Ethernet: Auto-negotiation failed - retrying

So the hardware cannot negotiate a link speed. The auto neg state is just read from the hardware so there is no bug to fix here. Either the network hub/switch is not advertising a speed we can support (eh half duplex modes only) or there is an Ethernet fault on your dock which was masked previously by us still establishing a link when half duplex modes were advertised.

Either way, I don't think this is a firmware bug, as we look to be correctly not bringing up a link because auto negotiation has failed.

Wim