https://bugzilla.kernel.org/show_bug.cgi?id=68571
--- Comment #28 from perry3d@gmail.com --- DPM is enabled by passing radeon.dpm=1 to the kernel paramters:
root@perry64 # cat /sys/kernel/debug/dri/64/radeon_pm_info uvd vclk: 0 dclk: 0 power level 2 sclk: 93000 mclk: 105000 vddc: 1185 vddci: 1150 root@perry64 # cat /sys/kernel/debug/dri/64/radeon_pm_info uvd vclk: 0 dclk: 0 power level 0 sclk: 10000 mclk: 15000 vddc: 950 vddci: 950
And no locks since two days.