Bug 107465

Summary: amdgpu.dc=1 triggers graphic card not recognizing native screen resolution
Product: DRI Reporter: Germano Massullo <germano.massullo>
Component: DRM/AMDgpuAssignee: Default DRI bug account <dri-devel>
Status: RESOLVED MOVED QA Contact:
Severity: normal    
Priority: medium CC: harry.wentland, nicholas.kazlauskas, sunpeng.li
Version: XOrg git   
Hardware: Other   
OS: All   
Whiteboard:
i915 platform: i915 features:
Attachments:
Description Flags
Xorg.0.log
none
dmesg none

Description Germano Massullo 2018-08-03 08:48:23 UTC 
Videocard: RX480
OS: Fedora 28 KDE
Kernel 4.17.9-200.fc28.x86_64

Sometimes when I poweroff the screen, then after some time I turn on it again, the system cannot recognize native screen resolution, and sets it to a weird one. In Plasma system settings, the monitor name is unknown and the native resolution is missing (1600x1050), other resolutions are available instead.. After playing with some resolutions, suddendly the screen name (ViewSonic etc.) returns back.

MrCooper user in #radeon Freenode chat, suggested me to start the system with amdgpu.dc=0 flag. 24 hours of testing seems to confirm that such flag fixes the problem.

I attach dmesg and xorg.0.log of system experiencing the problem
Comment 1 Germano Massullo 2018-08-03 08:49:10 UTC 
Created attachment 140947 [details]
Xorg.0.log
Comment 2 Germano Massullo 2018-08-03 08:51:34 UTC 
Created attachment 140948 [details]
dmesg
Comment 3 Germano Massullo 2018-09-02 09:26:10 UTC 
Just a clarification: title "amdgpu.dc=1" is not meant as having amdgpu.dc=1 as setted boot parameter, the situation is:
no boot parameter = problem triggered
amdgpu.dc=0 = no problem
Comment 4 Martin Peres 2019-11-20 07:50:39 UTC 
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