Lenovo thinkpad thunderbolt 3 dock gen 2 drops connected devices on Ubuntu Linux

I am using a Dell XPS 9570 laptop with dual boot Windows 10/Ubuntu 18.04 with lenovo thinkpad thunderbolt dock gen 2. The dock works fine on Windows. But on Ubuntu, it works for 5-10 minutes but then drops my connected devices like mouse, keyboard. The external monitor still works if I use the laptop keyboard or touchpad. I need to unplug and replug the thunderbolt cable for it to work, but it again drops the connections and its the same problem all over. How do I fix that?

I successfully updated the firmware/drivers for dock on Windows but that didn't help.

• Dock firmware version: V1.0.6.06161
• Dock driver version: V1.0.6.01201
• Windows 10 OS: Works fine
• Ubuntu 18.04: External input devices disconnects after sometime

1 Answer

I’ve seen the hub_ext_port_status failed (err = -110) message with Asus notebooks connected to docking ports in the past. A remarkable amount of effort, trial, and error later, the issue turned out to be a conflict between the USB 2.0 and 3.0 drivers — the ehci_pci kernel module, specifically.

To resolve the issue you can block the module but, be warned, this will affect how your machine uses USB2.0 devices. If your devices are mostly 3.0, which uses the xhci_pci kernel module, then you should have no serious issues.

So long as you’re good with this, follow these steps to test whether this is the issue or not:

1. Open Terminal (if it’s not already open)
2. Remove the ehci_pci kernel module:

   rmmod ehci_pci

3. Test your dock

If everything works well, then you can make this a permanent fix by adding the module to your modprobe.blacklist:

1. Open Terminal (if it’s not already open)
2. Edit /blacklist.conf as root:

   sudo vi /etc/modprobe.d/blacklist.conf

3. Add the following line:

   modprobe.blacklist=ehci_pci

4. Save the file
5. Reboot
6. Check the module is not loaded with:

   sudo lsmod

So long as your Dell is having the same issue I saw with Asus notebooks, this should be all you need.