(In reply to Julian from comment #65)
> sclk_dpm_key_disabled = 1;
> mclk_dpm_key_disabled = 0;
> pcie_dpm_key_disabled = 1;
> thermal_sclk_dpm_enabled = 1;
> ==> NO LOCKUP - however, I periodically checked
> /sys/kernel/debug/dri/0/radeon_pm_info and mclk never actually changed
> (always 150000). Maybe mclk usually always changes based on sclk? With slck
> locked, mclk wouldn't change either, even if unlocked.

What are you testing with?  You may not be producing enough memory load.