103863 – Screen doesn't light up with "amdgpu.dc=1"

Bug 103863 - Screen doesn't light up with "amdgpu.dc=1"

Summary: Screen doesn't light up with "amdgpu.dc=1"

Status:	RESOLVED WORKSFORME

Alias:	None

Product:	DRI
Classification:	Unclassified
Component:	DRM/AMDgpu (show other bugs)
Version:	unspecified
Hardware:	x86-64 (AMD64) Linux (All)

Importance:	medium major
Assignee:	Default DRI bug account
QA Contact:

URL:
Whiteboard:
Keywords:

Depends on:
Blocks:

Reported:	2017-11-23 09:37 UTC by Benjamin Bellec
Modified:	2017-11-23 19:27 UTC (History)
CC List:	3 users (show)

See Also:
i915 platform:
i915 features:

Attachments
dmesg log (4.05 KB, text/plain) 2017-11-23 09:39 UTC, Benjamin Bellec	no flags	Details
View All

Description Benjamin Bellec 2017-11-23 09:37:28 UTC

My screen doesn't light up if I start the kernel with option "amdgpu.dc=1"

Config is:
Fedora 27 + kernel 4.15.0-0.rc0.git7.1.fc28.x86_64
Radeon R9 380X
Dell U2414H


dmesg error is:
kernel: [drm:dm_logger_write [amdgpu]] *ERROR* perform_clock_recovery_sequence: Link Training Error, could not                          get CR after 100 tries.

Comment 1 Benjamin Bellec 2017-11-23 09:39:00 UTC

Created attachment 135680 [details]
dmesg log

Comment 2 Benjamin Bellec 2017-11-23 09:39:58 UTC

I forgot to precise this is a DisplayPort connection.

Comment 3 Jordan L 2017-11-23 18:08:44 UTC

Hi Benjamin,

Do you have a full dmesg log?

Also, would you be able to try with a different cable? It looks like a link training failure.

Thanks

Comment 4 Benjamin Bellec 2017-11-23 19:27:37 UTC

I reinstalled Fedora 26 (instead of 27) on my computer, and reinstalled the kernel 4.15.0-0.rc0.git7.1.fc28.x86_64 on it, and I haven't the error anymore...

Now I have a display and the HDMI audio on my second screen (TV in fact) is working.

Also, my F27 computer was on a new Ryzen config, which I finally reverted to old Core i5 due to global instability.

So I don't know where the problem was...

Use of freedesktop.org services, including Bugzilla, is subject to our Code of Conduct. How we collect and use information is described in our Privacy Policy.