https://bugzilla.kernel.org/show_bug.cgi?id=199749
--- Comment #21 from notsyncing (song.fc@gmail.com) --- (In reply to Andrey Grodzovsky from comment #20)
You just prepend this before command to start your graphic stack. You need to manually run your graphic stack from command line and add this before. E.G. for me on Ubuntu I will disable graphics launch on boot from GRUB. Then from terminal I will run GALLIUM_DDEBUG=always service lightdm start
I compiled and installed umr and executed "GALLIUM_DDEBUG=always service sddm start" on a root tty, and no "ddebug_dumps" directory was found in /root or in my home directory after desktop started. Is that normal?