(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?

It's probably better to avoid a wide setting like that. If you know some
applications that hangs (like Firefox or specific game), just set that when
launching it (you can for example add it to .desktop file or some start
script).