black screen with "drm/amd/display: Do not limit color depth to 8bpc" e03fd3f300f6184c1264186a4c815e93bf658abb >=4.18

Submitted by Andrey Arapov

Assigned to Default DRI bug account

Description

Hello,

some of the MacBookPro 14,3 users have been struggling with the black screen issue on their systems, I have been bisecting the kernel commits that came to v4.18-rc1 and found that the problem is gone when I revert this commit "drm/amd/display: Do not limit color depth to 8bpc" e03fd3f300f6184c1264186a4c815e93bf658abb

I presume that the driver cannot get the display_info.bpc from the screen so it defaults to COLOR_DEPTH_UNDEFINED causing the black screen.

Please let me know,

https://github.com/torvalds/linux/commit/e03fd3f300f6184c1264186a4c815e93bf658abb

Followed-by https://github.com/Dunedan/mbp-2016-linux/issues/73#issuecomment-422397681

Kind Regards,
Andrey Arapov

P.S. I have been sending an email to Harry Wentland & Alex Deucher on 18 Sept. 2018, but no response followed.