I'm running a Windows 7 guest in Debian Stretch/Testing. I'm Svs-V init instead of systemd. I'm using ALSA with Intel HD sound on the real motherboard.
I use it for VoIP mainly. I just upgraded from 5.0 to 5.1 and the microphone stopped working.
If you go to control panel -> sound -> recording tab, there's a "microphone" device with a green vertical VU bar next to it. In 5.0, this bounces up and down to reflect input from the microphone. In 5.1, this no longer has any activity.
I've tried both the front and rear jacks, and making sure that everything looks to be proper in alsamixer. I use the "Intel HD Audio" emulation, but I've also tried "ICH AC97" and installed the proper Windows 7 driver. I've tried the PIIX3 and ICH9 chipsets.
I tried using Pulseaudio. I switched to that in the VM audio settings and ran the Pulseaudio server. I got sound, but when I opened control panel -> sound -> recording, the VM instantly aborted and I got
kernel: threaded-ml: segfault at 5e16ef008 ip 00007f1922d9d4e0 sp 00007f192150ecf0 error 4 in libpulse.so.0.20.0[7f1922d78000+50000]
in the system logs.
If I downgrade back to 5.0, the microphone works again, on the same VM.
I've done a lot of Google searches and I appear to pretty much the only one having this problem.
Any suggestions? Any ideas what to try? I tried 5.1.2 today and no luck.