Bug 103863

Summary: Screen doesn't light up with "amdgpu.dc=1"
Product: DRI Reporter: Benjamin Bellec <b.bellec>
Component: DRM/AMDgpuAssignee: Default DRI bug account <dri-devel>
Status: RESOLVED WORKSFORME QA Contact:
Severity: major    
Priority: medium CC: b.bellec, harry.wentland, jordan.lazare
Version: unspecified   
Hardware: x86-64 (AMD64)   
OS: Linux (All)   
Whiteboard:
i915 platform: i915 features:
Attachments:
Description Flags
dmesg log none

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...

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