Comment # 59 on bug 99851 from erhard_f@mailbox.org

Tried kernel 4.17.2 and was surprised to see that this bug does not seem to
bother my G5 11,2 any longer! Now my HD 6450 passes all ring tests and I can
run X11 with glamor happily again. \o/

Hopefully this bug is gone for good. Salute to the hard working kernel/AMD
developer who made this possible! ;)