I'm on a Lenovo t450s and Xubuntu 16.04. When I connect a monitor via displayport and enable it e.g. using xrandr, nothing shows on the screen (except "no signal"), and the following message shows up in dmesg:
[drm:intel_dp_start_link_train [i915]] *ERROR* failed to train DP, aborting
I've tried upgrading the linux kernel to 4.6.0, but the problem persists. I can connect an external monitor via the docking station, but using the mini displayport does not work. Not sure if related, but connecting multiple monitors using displayport on the docking station produces the same result, sometimes accompanied by a system freeze.
I saw a few bugreports on similar issues, but they seem either outdated or not directly related.
Any ideas? Thanks in advance!