https://bugs.freedesktop.org/show_bug.cgi?id=92982

--- Comment #12 from royvandervegt@gmail.com --- Interestingly enough, it seems to have little to do with the clock speeds.

With dpm turned on and radeon_dpm_force_performance_level set to high (doesn't switch properly):

uvd vclk: 0 dclk: 0 power level 2 sclk: 75000 mclk: 80000 vddc: 1120 vddci: 0

With radeon.dpm=0 (WORKS, switches quickly): default engine clock: 750000 kHz current engine clock: 749980 kHz default memory clock: 800000 kHz current memory clock: 799870 kHz voltage: 1120 mV PCIE lanes: 16