Comment 9 for bug 1842954

I'm also experiencing this problem after upgrading to Ubuntu 19.10. I'm using xserver-xorg-video-amdgpu 19.0.1-1ubuntu1 so either it's not completely fixed, or I'm experiencing a different but very similar issue.

One of the linked bug reports suggested the crash occurs in the XFCE compositor. I tried disabling the compositor:

xfconf-query -c xfwm4 -p /general/use_compositing -s false

This seems to be a usable workaround for now, though it does introduce some visual glitches.

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More detail:

After booting to login screen, if I select an "XFCE" or "Xubuntu" session and log in, the system crashes to a black screen and is unresponsive to Ctrl-Alt-F2 or Ctrl-Alt-Del or anything else I try. (Alt+SysRq+b does reboot though.)

Selecting an "Ubuntu" session is fine.

After rebooting, I see 232 lines in syslog like this:

WARNING: CPU: 2 PID: 274 at drivers/gpu/drm/amd/amdgpu/../display/dc/dcn10/dcn10_hw_sequencer.c:932 dcn10_verify_allow_pstate_change_high.cold+0xc/0x23d [amdgpu]

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Hardware and version info:

$ cat /proc/cpuinfo
model name : AMD Ryzen 5 2400G with Radeon Vega Graphics

$ lsb_release -a
Description: Ubuntu 19.10
Release: 19.10
Codename: eoan

$ uname -r
5.3.0-23-generic

$ apt show xserver-xorg
Version: 1:7.7+19ubuntu12

$ apt show xserver-xorg-core
Version: 2:1.20.5+git20191008-0ubuntu1

$ apt show xserver-xorg-video-amdgpu
Version: 19.0.1-1ubuntu1

$ xfce4-session --version
xfce4-session 4.14.0 (Xfce 4.14)