Hi

I experience annoying bug when I turn on my dual-monitor PC after some time is
turned off state.
Basically it results in following:

+-----------+
|   OK      |
|           |
+-----------+------------------+
|           |                  |
|           |                  |
| GARBAGE   |  GARBAGE         |
|           |                  |
|           +------------------+
|           |
|           |
+-----------+

X Windows render a small part of screen ("OK" area), everything else is
garbage, quite often flicking. Changing VT does not help.

Tested under Linux x64 5.1.6 + xorg-server-1.20.5 + amdgpu driver from git.
Hardware: XFX RX580 8GB