Operating system: Ubuntu 18.04 LTS and 19.04
Graphics card: Sapphire Radeon RX 5700 ("reference card")
Broken: tested (2.81 Alpha, 900a9a4b06a6, master, 2019-09-25) and (2.80 Release, 2019-07-30)
Worked: (2.79.b, 2019-09-24 last updated in repository)
Short description of error
If I try to open Blender the screen (to be more exact both of my screens) freeze. The audio of music or videos I had opened in other applications still play but everything is frozen except my mouse-cursor. But not a single window reacts to clicks or any key-presses. I can only end this state of my system by rebooting the whole computer. So I can't practically use the current version of Blender.
Exact steps for others to reproduce the error
If you have a Navi-GPU from AMD and their amdgpu-pro-drivers installed (which support Ubuntu 18.04) on Ubuntu 18.04 or 19.04, you should be able to reproduce it by executing the "blender" called binary from Blender 2.80. The other binary "blender-softwaregl" does not cause this error in any version tested but is rather slow in performance (but I guess this is expected).
My thoughts what causes the problem
The reason I post this problem around here and not only to the side of AMDs support fixing the drivers is that I think I know what's causing this problem. Because Blender 2.79 still seems to work fine on Ubuntu, I thought it could have something to do with Blender using Uniform Buffer Objects or even Shader Storage Buffer Objects from OpenGL in a wrong way. This thought came to me when I tried to develop an own application on my system using OpenGL 4.3 and its SSBOs in a shader but I made the mistake to call the shader before binding a SSBO to the appropriate Shader Storage Buffer Block. The result was the same error I got from calling Blender. So maybe it could just be fixed like in my own code by swapping some few lines in order which would remove this undefined behavior which causes this problem with the current Navi-drivers from AMD. Because I think AMD will probably need more time than you guys. Keep up the great work!