Comment # 7 on bug 106303 from Mike

Power usage partially improved with kernel 4.17.2
Both MCLK and SCLK now lowered to full idle - when monitor is turned OFF.

Also MCLK seems to go idle (300MHz) periodically under low load (2D and
browsing).
However, SCLK is still run at top values when monitor is ON, regardless of GPU
load (it is about 1-2% according to radeontop utility).