Bug 112288

Summary: Blank display on Ubuntu 19.10 on Ryzen 3 2200G and Ryzen 5 2400G APUs
Product: DRI Reporter: mortenkjeldgaard
Component: DRM/AMDgpuAssignee: Default DRI bug account <dri-devel>
Status: RESOLVED MOVED QA Contact:
Severity: major    
Priority: not set CC: kai.heng.feng
Version: XOrg git   
Hardware: x86-64 (AMD64)   
OS: Linux (All)   
i915 platform: i915 features:
Description Flags
dmesg output none

Description mortenkjeldgaard 2019-11-14 19:56:48 UTC
Filing bug report here on request by Ubuntu bug team, please see discussion on https://bugs.launchpad.net/ubuntu/+source/xserver-xorg-video-amdgpu/+bug/1848900

My problem arose after upgrading Ubuntu 19.04 -> 19.10. The lighted welcome screen displays fine, but when I try to log in I get a black screen and the monitor appears to be frozen (can't switch to virtual terminal either). The machine is running normally and I can log on via ssh.

Other users in the above mentioned bug on LP have different variations of the same problems, some have problems using the live DVD.
Comment 1 Alex Deucher 2019-11-14 19:59:05 UTC
Can you bisect?
Comment 2 mortenkjeldgaard 2019-11-14 20:01:52 UTC
(In reply to Alex Deucher from comment #1)
> Can you bisect?

I am not a developer, just a user. All I can tell you is that the problem arises when upgrading Ubuntu from 19.04 to 19.10.
Comment 3 Alex Deucher 2019-11-14 20:02:20 UTC
from your dmesg output:
[    1.094054] [drm:amdgpu_init [amdgpu]] *ERROR* VGACON disables amdgpu kernel modesetting.
Did you enable vga console?
Comment 4 Alex Deucher 2019-11-14 20:03:54 UTC
Can you get the dmesg output from when the driver is loaded?
Comment 5 mortenkjeldgaard 2019-11-14 20:10:13 UTC
Created attachment 145957 [details]
dmesg output
Comment 6 Alex Deucher 2019-11-14 20:17:19 UTC
Do any of the display connectors work properly?  If so which?
Comment 7 mortenkjeldgaard 2019-11-14 20:26:07 UTC
I am using the DVI port for my monitor. I can't test the VGA port on the motherboard because I don't have a VGA cable, and my monitor is old and doesn't have an HDMI port. Sorry.
Comment 8 Peter D. 2019-11-15 02:54:19 UTC

I'm the Peter D. who raised the Ubuntu bug report - writing from a different email address.  I can probably bisect the kernel with a little gentle instruction. 

Initial results are;
Raven ridge APU, VGA port, slow monitor (75Hz max refresh rate),
booting with nomodeset gives a stable display, but a very odd result from xrandr. 

psd@EE:~$ xrandr
xrandr: Failed to get size of gamma for output default
Screen 0: minimum 1920 x 1080, current 1920 x 1080, maximum 1920 x 1080
default connected 1920x1080+0+0 0mm x 0mm
   1920x1080     77.00* 

Booting new kernels (5.3 onwards?) and no "nomodeset" gives either a blank screen or a very unstable screen with lots of pixelation and a high risk of going black.  Here is something that I captured earlier: 

psd@EE:~$ xrandr
Screen 0: minimum 320 x 200, current 1920 x 1080, maximum 16384 x 16384
DisplayPort-0 disconnected primary (normal left inverted right x axis y axis)
HDMI-A-0 disconnected (normal left inverted right x axis y axis)
DisplayPort-1 connected 1920x1080+0+0 (normal left inverted right x axis y axis) 531mm x 298mm
   1920x1080     60.00*+
   1680x1050     60.00
   1280x1024     60.02
   1440x900      59.89
   1280x800      59.81
   1152x864      75.00
   1280x720      60.00
   1024x768      70.07    60.00
   800x600       60.32    56.25
   640x480       66.67    59.94
   720x400       70.08

"DisplayPort-1" is actually a VGA port.  I believe that there is a conversion chop on the motherboard, an ASROCK B450 Pro4. 

Give me some time to swap hardware again.
Comment 9 Peter D. 2019-11-15 04:29:08 UTC
All three ports work.  

If my computer boots to a blank screen, plugging in a second monitor "resets" the video and both screens display the desktop as clones.  

There are two monitors; a slow one with a maximum vertical refresh rate of 75 Hz, and a fast one with a maximum vertical refresh rate of 144 Hz.  The fast monitor has DP, HDMI and VGA ports.  The slow monitor has VGA and DVI ports.  The motherboard has DP, HDMI, and VGA ports.  Currently there are cables that can reach ... 
MoBo DP fast monitor
Mobo HDMI (passive adapter) DVI slow monitor
Mobo VGA slow monitor
This can be rearranged if need be.

The reset trick has happened with; 
the slow monitor plugged into the VGA port and being revived when the fast monitor was plugged into the DP, and with 
the fast monitor plugged into the DP and being revived when the slow monitor was plugged into the HDMI port.

Currently using a mainline kernel downloaded from Ubuntu. 

psd@EE:~$ uname -a
Linux EE 5.4.0-050400rc7-generic #201911102031 SMP Mon Nov 11 01:34:23 UTC 2019 x86_64 x86_64 x86_64 GNU/Linux
Comment 10 Timo Aaltonen 2019-11-15 05:34:25 UTC
maybe try drm-tip mainline build to see if it's any better?
Comment 11 Michel Dänzer 2019-11-15 09:12:01 UTC
(In reply to Alex Deucher from comment #3)
> [    1.094054] [drm:amdgpu_init [amdgpu]] *ERROR* VGACON disables amdgpu
> kernel modesetting.
> Did you enable vga console?

FWIW, that message is due to "nomodeset" on the kernel command line, which was presumably used to work around this problem?
Comment 12 Alex Deucher 2019-11-15 15:24:50 UTC
Does disabling the iommu help?  Append iommu=off or iommu=pt to the kernel command line.
Comment 13 Martin Peres 2019-11-19 10:01:49 UTC
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