And no, the Ultra dock is no solution, it's an MST hub. It's painfully obvious the docking connector only has a single DP 1.2 connection running in it. But is it the same DP 1.2 output as the one routed into the USB C? It doesn't need to be , the GPU is triple display capable, after all. But then again, we are talking of Lenovo.
https://support.lenovo.com/de/en/solutions/pd029622 this doesn't have the T470 listed. http://s3.amazonaws.com/isby/lenovopart ... utions.pdf is mum on the topic. I tried. I really tried. No info anywhere.
To muddle the waters:
that's four options while Intel 620 only supports three. One needs to give. How is this actually routed? To make things even worse some T470 have a 940MX in them (for sure my T25 will have) which, being Maxwell, is certainly capable of quad displays. Is that why there's a 940MX in the first place?? In which basement does Lenovo keep system diagrams and what's the URL to there ?Boot Display Device
Values: ThinkPad LCD, USB Type-C, HDMI,Display on dock
Description: Select the display device that you want to activate at boot time. This selection is effective for boot time, password prompt, and ThinkPad Setup. USB Type-C corresponds to the USB Type-C connector on your computer. HDMI corresponds to the HDMI connector on your computer. Display on dock corresponds to the video connectors (such as the DisplayPort, DVI, or VGA connectors) on a docking station. Boot screen is cloned to all displays on dock.