Bug 108693

Summary:	black screen with "drm/amd/display: Do not limit color depth to 8bpc" e03fd3f300f6184c1264186a4c815e93bf658abb >=4.18
Product:	DRI	Reporter:	Andrey Arapov <andrey.arapov>
Component:	DRM/AMDgpu	Assignee:	Default DRI bug account <dri-devel>
Status:	RESOLVED MOVED	QA Contact:
Severity:	major
Priority:	medium	CC:	harry.wentland, nicholas.kazlauskas, ronny.standtke
Version:	XOrg git
Hardware:	x86-64 (AMD64)
OS:	Linux (All)
Whiteboard:
i915 platform:		i915 features:

Description Andrey Arapov 2018-11-08 10:59:18 UTC

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.

Comment 1 Ronny Standtke 2018-11-08 18:52:32 UTC

I can confirm the bug. We provide an exam environment based on Debian Live. Since we switched to Kernel 4.18 (provided in Debian backports) we have seen *many* Macs failing to boot and just showing a black screen. So at least for us this regression is quite severe...

Comment 2 Alex Deucher 2018-11-08 19:27:54 UTC

This patchset may help:
https://patchwork.freedesktop.org/series/52164/

Comment 3 Andrey Arapov 2018-11-20 12:45:37 UTC

(In reply to Alex Deucher from comment #2)
> This patchset may help:
> https://patchwork.freedesktop.org/series/52164/

Thank you, Alex.

I can confirm, the patches worked for me.
I have adapted them for Linux 4.19.2 -  https://gist.github.com/arno01/8115ef124fe7f42bbf1c317892013e86


Any plans for including them in the next Linux release?

Kind Regards,
Andrey Arapov

Comment 4 Alex Deucher 2018-11-20 15:31:29 UTC

(In reply to Andrey Arapov from comment #3)
> (In reply to Alex Deucher from comment #2)
> > This patchset may help:
> > https://patchwork.freedesktop.org/series/52164/
> 
> Thank you, Alex.
> 
> I can confirm, the patches worked for me.
> I have adapted them for Linux 4.19.2 - 
> https://gist.github.com/arno01/8115ef124fe7f42bbf1c317892013e86
> 
> 
> Any plans for including them in the next Linux release?

yes.  They should land in 4.20 soon.

Comment 5 Martin Peres 2019-11-19 09:03:37 UTC

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