Comment # 85 on bug 75985 from Przemysław Kopa

> Something has forced the HDA on, hence it doesn't autosuspend.
> 
> Does the issue go away if you re-enable runtime suspend? Try:
> 
> echo auto > /sys/bus/pci/devices/0000:01:00.1/power/control

Unfortunately, it doesn't - HDA still stays active.

cat /sys/bus/pci/devices/0000:01:00.1/power/control
auto

cat /sys/kernel/debug/vgaswitcheroo/switch
0:IGD:+:Pwr:0000:00:02.0
1:DIS-Audio: :DynPwr:0000:01:00.1
2:DIS: :DynPwr:0000:01:00.0