I can also confirm this for a Lenovo ThinkPad T430s with Lenovo ThinkPad Mini Dock Plus Series 3.
OS: Ubuntu 14.04.1 Kernel: Linux ThinkPad 3.13.0-36-generic #63-Ubuntu SMP Wed Sep 3 21:30:07 UTC 2014 x86_64 x86_64 x86_64 GNU/Linux
I can also confirm this for a Lenovo ThinkPad T430s with Lenovo ThinkPad Mini Dock Plus Series 3.
OS: Ubuntu 14.04.1
Kernel: Linux ThinkPad 3.13.0-36-generic #63-Ubuntu SMP Wed Sep 3 21:30:07 UTC 2014 x86_64 x86_64 x86_64 GNU/Linux