Bug 200633

Summary:	[Regression] VGA not being detected with R9 380 using AMDGPU after 4.17 kernel update.
Product:	Drivers	Reporter:	syboxez
Component:	Video(DRI - non Intel)	Assignee:	drivers_video-dri
Status:	NEW ---
Severity:	low	CC:	alexdeucher, harry.wentland, syboxez
Priority:	P1
Hardware:	x86-64
OS:	Linux
Kernel Version:	4.17	Subsystem:
Regression:	Yes	Bisected commit-id:
Attachments:	dmesg log Xorg log

Description syboxez 2018-07-23 20:03:19 UTC

OS: Debian Sid
Kernel: 4.17.8
GPU: AMD R9 380
Mesa version: 18.1.4

After upgrading from 4.16 to 4.17 (this bug was also reproduced on 4.18-RC3), xrandr reports VGA displays (normally DVI-I-1 in my case) as digital displays (DVI-D-1), and will display a black screen on the monitor I am attempting to use. In 4.16, it worked perfectly. Booting the system with the 4.16 kernel resolves the issue.

I will be happy to collect any useful logs upon request, as I'm not too sure what to look for.

Comment 1 Michel Dänzer 2018-07-24 07:51:01 UTC

Please attach the dmesg output and Xorg log file corresponding to the problem.

amdgpu.dc=0 on the kernel command line might serve as a workaround for the time being.

Comment 2 syboxez 2018-07-24 17:49:25 UTC

dmesg: https://ghostbin.com/paste/7pyty
Xorg: https://ghostbin.com/paste/38zyy

amdgpu.dc=0 does indeed make the issue go away, so I'm guessing DC was turned on by default for Tonga in this kernel.

Comment 3 Michel Dänzer 2018-07-25 07:51:52 UTC

(In reply to syboxez from comment #2)
> dmesg: https://ghostbin.com/paste/7pyty
> Xorg: https://ghostbin.com/paste/38zyy

Thanks, but please attach files here directly instead of referencing an external pastebin site.

Comment 4 syboxez 2018-07-25 17:42:48 UTC

Created attachment 277521 [details]
dmesg log

Comment 5 syboxez 2018-07-25 17:43:16 UTC

Created attachment 277523 [details]
Xorg log