While playback this sample video:
uvd    vclk: 53334 dclk: 40000
power level 0    sclk: 49231 vddc: 975

Quote from dmesg:
[147358.038752] switching from power state:
[147358.038772]         ui class: performance
[147358.038778]         internal class: none
[147358.038782]         caps: 
[147358.038787]         uvd    vclk: 0 dclk: 0
[147358.038793]                 power level 0    sclk: 27827 vddc: 900
[147358.038796]                 power level 1    sclk: 49231 vddc: 975
[147358.038799]         status: c 
[147358.038803] switching to power state:
[147358.038805]         ui class: none
[147358.038807]         internal class: uvd 
[147358.038811]         caps: 
[147358.038814]         uvd    vclk: 53334 dclk: 40000
[147358.038817]                 power level 0    sclk: 49231 vddc: 975
[147358.038819]         status: r