Lenovo ThinkVision P27h-20 screen randomly turns off when connected to MacBook Pro

The Lenovo ThinkVision P27h-20 screen I get from work is a decent 27 inch screen. Coming from the Retina screen of my laptop that I worked on for a long time, I was initially (and still am) not impressed by the resolution of 2560×1440. It took some time to get used to the low resolution on such a big screen, but it gets the job done…

My biggest gripe with the screen was that it just randomly turned off when connected to my MacBook Pro in clamshell mode. I finally found the culprit after combing through the Console system logs for any trace for the longest time. I found out that the MacBook Pro thought the power was changing from grid to battery and vice versa (all while being constantly on-power), and whenever it did that, the screen would turn off.

The solution was to disable the "Smart Power" option in the screen's settings. According to the manual, the "Smart Power" option does the following:

Smart Power intelligently distributes power to connected USB and USB Type-C devices, maximizing power supply efficiency while also reducing overall consumption.

Turns out, it wasn't so smart after all. I saw it range between 65W and 90W, but after turning the option off, the laptop gets a constant 65W, all my USB-C devices still work, and I'm happy to report that the screen no longer randomly turns off. This is the blog post I wish I had found when I was looking for a solution, so I hope it helps someone else.