Graphics corruption on external displays only when lid is closed?

[eekcat]

I just picked up a MBP Touch Bar (2016) w/ Radeon 455, and have two Dell P2715Q (4k) displays connected to it. A very smooth experience, except that I get odd graphics-corruption (checker boarding, it looks like) on the external displays only if the Macbook's lid is closed.

Ordinarily, I'd suspect that maybe the display cables aren't up to snuff or the MacBook somehow wasn't up to driving two 4k monitors, but it does work fine with the lid open.

Has anyone seen this, or have a solution?

 

[casperes1996]

Does it happen on both displays? Are the displays connected independently or through a single port? Does it always happen or just sometimes?

 

[eekcat]

Does it happen on both displays? Are the displays connected independently or through a single port? Does it always happen or just sometimes?

Both displays. They are connected independently (using USB-C to DisplayPort adapters that support 4k/60hz, two different brands/types, same issue). Always happens.

 

[friednoodles]

I assume it's already running macOS High Sierra? If so, there are a lot of GPU/graphics/driver issues with both internal and external displays. e.g:

https://forums.macrumors.com/thread...ot-work-after-resume-from-long-sleep.2076334/
https://discussions.apple.com/thread/8141739

And bugs specific to external displays...

https://discussions.apple.com/thread/8150105

And it seems there's not a lot that can be done about it right now. If you didn't restore from a backup and you haven't loaded much on to it yet, it may well be worth your time to do a fresh install using macOS Sierra instead of High Sierra to see if the issue is resolved, because in general Sierra is a lot more stable and reliable right now, so there's a good chance the external monitor issue you're having won't happen with it.