audiodg.exe is a “protected process lite” (PPL) process on Windows Vista
through Windows 8.1 inclusive. If your APO is not adequately signed, it will
not be loaded into audiodg.exe at all. (This recursively applies to any
dependencies your APO has.)
HDC will adequately sign your APO if you set the [SignatureAttributes]
PETrust=true attribute on it as documented here:
You can use signtool.exe to verify the adequacy of the signature:
As of Windows 10, audiodg.exe is no longer a PPL.
From: Tim Roberts<mailto:timr@xxxxxxxxx>
Sent: Wednesday, December 11, 2019 10:33 AM
Subject: [EXTERNAL] [wdmaudiodev] Re: LFX APO on Windows 7 x64
1. Do we need MS EV certificate for userspace drivers and APOs? Or
what kind of digital signature and its properties Windows 7 x64
expects for APO dlls?