Ok, so this driver definitely has broken the audio part. On my HP dv6 laptop with IDT audio drivers (latest, but it's irrelevant - tried different versions, nothing changes because it's not their fault), when run with connected charger - everything is fine, but when on battery - I have to either:
A) Disable Intel Audio in Device Manager & perform restart
or
B) Disable & enable again the IDT audio device AFTER EVERY REBOOT
otherwise I will have no sound from the built in audio. This happens only when run on battery (Windows 7 SP1 x64, latest updates).
BUT I reinstalled the drivers, but first replaced the audio driver folder with the one from previous version et voila - everything works just as it should, perfectly ok, so it's definitely Intel HD Audio latest driver fault. Also it does weird things with default audio device settings, so you guys should really take a look into the audio part as something wonky is happening there.