https://bugs.freedesktop.org/show_bug.cgi?id=91880
--- Comment #164 from Thomas DEBESSE dev@illwieckz.net --- (In reply to Jon Doane from comment #159)
I've literally been doing: "echo high > /sys/class/device/drm/card0/power_dpm_force_performance_level" every day to boot my machine for over a year
See comment 55 if your system is running systemd, you can use this service:
https://github.com/illwieckz/dpm-query/
It will do it for you at startup, it's painless and I'm using it since 19 months without any issue.