I've found the root cause of the issue - APOs appears unsigned for
Windows 7 despite it has all updates installed and the dll is actually
signed. When I set "DisableProtectedAudioDG" to 1 everything works
We sign it with EV digicert certificate using /fd sha256 and this
perfectly works in Windows 10. Also in Windows 7 if I right click and
look at the properties->digital signature everything looks OK.
But when I open "driver details" tab for the device in device manager,
it shows "Not digitally signed" for our APO dll. So, there are 2
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?
2. Why Windows calls Initialize() & isFormatSupported() when APO is unsigned?
On Tue, 10 Dec 2019 at 19:24, Matthew van Eerde
The wFormatTag values are defined in mmreg.h. 85 = 0x55 =
Sent: Tuesday, December 10, 2019 12:03 AM
Subject: [EXTERNAL] [wdmaudiodev] LFX APO on Windows 7 x64
I have an APO (that does some sound virtualization stuff) in LFX on
Windows 7 x64 and on some machines windows continuously calls this
(for stereo source):
guidFormatType: 3Input format:
guidFormatType: 3Output format:
This repeats many times and format seems to be the same. Once I saw
something like (not sure what 85 means):
guidFormatType: 85Input format:
I have implemented IsInputFormatSupported() and it basically accepts
all input channel configurations and then calls base class, but
skipped implementation of IsOutputFormatSupported().
Everything works perfectly on Windows 10 and some Windows 7 PCs, but
on some Windows 7 PCs I see the behavior described above. I can't see
the difference between OSs,
all updates are there and build numbers are the same.
Please advice something, I've already cracked my head :) I know that
Windows 7 is going away, but we have requirements to support it.
Post message: mailto:wdmaudiodev@xxxxxxxxxxxxx
URL to WDMAUDIODEV page: