[Bug 199749] amdgpu on Ryzen 2400G freeze randomly

https://bugzilla.kernel.org/show_bug.cgi?id=199749

--- Comment #17 from notsyncing (song.fc@gmail.com) --- (In reply to Andrey Grodzovsky from comment #16)

Then launch your X with ENV variable GALLIUM_DDEBUG=always to dump all the 3D commands into files in ~/ddebug_dumps/

Would you mind telling me how to add this variable? I googled and cannot find any information. Should I add it to /etc/X11/Xsession or something else? Thanks very much!

I'm on kernel 4.17.2-041702-generic, Ubuntu 18.04, mesa 18.1.1-1ubuntu1~18.04.0~ppa1