Just to add some informations :
No sound via DP
Fresh install of W10 1709
tried to install W10 1511 same problem
The device disappears when the surface wake up from sleep
can't find a driver containing VEN_8086&DEV_0A0C or VEN_8086&DEV_9C20
sometimes the error is on 9C20 device, sometimes the 0A0C
found on other threads that it could be related to MS docking station which I don't use
Only workaround i've found on other thread is to uninstall both HDAC drivers while DP is conncted. Look up for hardware changes, then sound works via DP.
But when i disconnect the DP, no sound on the surface and have to reboot it. The Realtek HDAC disappear too in "sound, video, games controllers and won't shows up.
Thanks guy !
