https://bugs.freedesktop.org/show_bug.cgi?id=82201
--- Comment #50 from Alex Deucher alexdeucher@gmail.com --- (In reply to Sebastian Parborg from comment #49)
Where can I check the levels that "high" is supposed to clock to?
It will be reflected in radeon_pm_info in debugfs if it worked. You can see additional information about the selected power states in the kernel log if you boot with radeon.dpm=1 on the kernel command line in grub.