(In reply to Jaap Buurman from comment #142)
> How can I set both AMD_DEBUG=nongg and AMD_DEBUG=nodma in the
> /etc/environment file? Do they need to be on two separate lines, or will the
> second line simply overwrite the first one by setting the same environment
> variable? Do they need to be comma separated maybe?

Add the following line to your /etc/environment

export AMD_DEBUG=nongg,nodma

(In reply to Pierre-Eric Pelloux-Prayer from comment #141)
> I don't think radv uses SDMA at all, so they cannot be affected by this
> issue. 

Correct, radv doesn't use the SDMA so is not affected by this problem. If you
see hangs in Vulkan games, it is currently most likely an LLVM problem. The
LLVM devs have fixed most of the problems in their latest master, but haven't
backported the fixes to LLVM 9 yet.