I own a Macbook Pro 13 2017 (2 thunderbolt ports), and I would like to disable the internal display when an external monitor is connected to it through USB-C.
I have ruled out the following
- Turn brightness all the way down in mirrored display mode: Not the best, because the GPU's framebuffer is still doing extra work on that internal display (processing power and battery affected).
- Using Clamshell mode: Again, not the best. I only got two USB-C ports, one would be taken by AC power which is a prerequisite for this mode, and another displaying to the external monitor.
- Add "niog=1" on NVRAM: Sounds OK, but still a hassle to reset NVRAM every time I want to work on the internal display.
I can think of two solutions
- Simulate what is happening to macOS on Clamshell mode without actually closing the lid.
- Simulate the Macbook on AC adapter power so I can use Clamshell mode with one USB-C port free.
I would appreciate feedback on this, it would be great to nail this issue.
Best Answer
Why not put a small and not super powerful magnet on the specific area of the sleep wake sensor so that the system thinks the lid is shut?
With power and keyboard connected, you'll have it running in closed-clamshell mode with full benefits for your use case and no need to move the actual display.
There are amazing USB-C pass through docks now - some that sit flush and others with a stand off cable so you can get around the limitation of only having two ports if that's the only sticking point for clamshell mode.
The good adapters are still in the $50 US range, but the knock off ones are rapidly approaching $10 so you can pick metal or plastic and your warranty / support model of choice if you run out of ports.