I have the same exact issue.
I'm using the Lenovo IdeaPad Yoga 13 with the Lenovo USB 3.0 dock. The screen is recognized, I can move windows and the cursor to the other screen, but it remains black.
I tried and read about everything on this forum, and nothing works. I'm pretty sure it's not a hardware issue. Could it be caused by the Intel HD Graphics 4000? Could it interfere with the HDMI output? I'm out of ideas.
|