Bug 23855

Summary:	Introduces display detection(?) errors with amdgpu, not present in kernel 4.19.1
Product:	Mageia	Reporter:	Richard Walker <richard.j.walker>
Component:	RPM Packages	Assignee:	Kernel and Drivers maintainers <kernel>
Status:	RESOLVED FIXED	QA Contact:
Severity:	normal
Priority:	Normal	CC:	marja11
Version:	Cauldron
Target Milestone:	---
Hardware:	All
OS:	Linux
Whiteboard:
Source RPM:	kernel-4.19.2-3.mga7.src.rpm	CVE:
Status comment:
Attachments:	boot log from kernel-desktop-4.19.2 boot log from kernel-desktop-4.19.1

Description Richard Walker 2018-11-18 02:40:55 CET

Description of problem:
system is AMD A10-7860 Kaveri on Asus motherboard A88XM-PLUS having DVI, HDMI and VGA display ports. With three displays connected, the VGA display is no longer detected. Typical error messages are:

Nov 17 01:35:21 xxxx kernel: [drm:construct [amdgpu]] *ERROR* construct: Invalid Connector ObjectID from Adapter Service for connector index:1! type 0 expected 3
Nov 17 01:35:21 xxxx kernel: [drm:construct [amdgpu]] *ERROR* construct: Invalid Connector ObjectID from Adapter Service for connector index:3! type 0 expected 3
Nov 17 01:35:21 xxxx kernel: [drm:construct [amdgpu]] *ERROR* construct: Invalid Connector ObjectID from Adapter Service for connector index:4! type 0 expected 3
Nov 17 01:35:21 xxxx kernel: [drm:construct [amdgpu]] *ERROR* construct: Invalid Connector ObjectID from Adapter Service for connector index:5! type 0 expected 3



Version-Release number of selected component (if applicable):


How reproducible:
Every boot with kernel 4.19.2

Steps to Reproduce:
1. boot
2.
3.

Comment 1 Richard Walker 2018-11-18 02:56:15 CET

Created attachment 10484 [details]
boot log from kernel-desktop-4.19.2

What looks like display detection errors can be found at Nov 17 01:35:21 in the log.

Comment 2 Richard Walker 2018-11-18 02:59:46 CET

Created attachment 10485 [details]
boot log from kernel-desktop-4.19.1

Correct display detection is noted in this log at Nov 17 01:27:16

Marja Van Waes 2018-11-19 17:38:01 CET

CC: (none) => marja11
Assignee: bugsquad => kernel

Comment 3 Richard Walker 2018-12-03 01:17:31 CET

After reviewing boot logs from October I found the cause of the problem to be the use of the amdgpu.dc=1 parameter setting on the command line. Kernels since version 4.19.1-desktop-4.mga7 (the last one where this parameter was harmless) will fail to detect displays, perhaps just the VGA display, when this parameter is used set to 1. 

I have now set it to -1 but I do wonder if this is a regression or if my Kaveri is really not meant to use Display Core.

This may therefore be nothing more than a workaround and a bug may still exist, but as I do not have the expertise to determine this I have elected to close this bug now. If I have time to do more research I may re-open it.

Status: NEW => RESOLVED
Resolution: (none) => FIXED