Hello! I can confirm that I have the same issues. I am using a=
 Vega 56 and
openSUSE Tumbleweed (X11 and KDE) with:

Kernel Version:  5.1.5-1-default
X Server Release:  12004000
Driver:  X.Org Radeon RX Vega (VEGA10, DRM 3.30.0, 5.1.5-1-default, LLVM 7.=
0.1)

I have been having the same freezes exactly as described here since, as far=
 as
I can remember, mesa 19.0.4 and 5.0.13 (based on the Tumbleweed snapshots f=
rom
when this started happening)

This was definitely not happening before on mesa 18.x/LLVM 6 and 7 and kern=
el
4.20. I niehter run overclocks, never messed with firmware/BIOS...etc.
Everything has been running as-is since Oct. 2018 so firmware or BIOS issues
should be discarded, I guess.

In my case, I have also experienced this issue when running non-demanding
OpenGL games and even desktop applications (I had a crash happen on the des=
ktop
with just WxMaxima, a computer algebra system GUI, opened doing nothing)

The easiest way for me to reproduce it is by simply leaving Pillars of Eter=
nity
(an OpenGL unity game) open and idle for an hour or so. I have tried settin=
g up
Kdump and trying to catch some error messages in the logs with no luck. I'm
definitely open for directions on how to get more info if this can help.