Re: Fwd: Can't get audio, host Debian, guest NetBSD, help!

[mlelstv%serpens.de@localhost (Michael van Elst)]

ottavio2006-usenet2012%yahoo.com@localhost (Ottavio Caruso) writes:

>#!/bin/sh
>/home/oc/git/qemu/build/qemu-system-x86_64 \
>-drive if=virtio,file=/home/oc/VM/img/netbsd.image,index=0,media=disk \
>-drive if=virtio,file=/home/oc/VM/img/netbsd.image.old,index=1,media=disk \
>-M q35,accel=kvm -m 500M -cpu host -smp $(nproc) \
>-nic user,hostfwd=tcp:127.0.0.1:5555-:22,model=virtio-net-pci,ipv6=off  \
> -device intel-hda -device hda-duplex \
>-serial mon:telnet:127.0.0.1:6665,server,nowait \
>-pidfile /home/oc/VM/pid/netbsd-pid

>See the " -device intel-hda -device hda-duplex " line? I am not sure
>if this is enough, but I can see the audio device in the guest:


The -audiodev option is missing that tells qemu how to talk to the
host audio system.

The NetBSD guide has a chapter about emulation and proposes the
'oss' backend, see:

https://www.netbsd.org/docs/guide/en/chap-virt.html#chap-virt-qemu-audio

'oss' and also the 'sdl' backend both seem to work somewhat,
but here qemu was much too slow to drive an audio stream,
the result was pretty noisy.

Also, audio usually requires proper timing. For a NetBSD
host this means that it needs to run a kernel with a higher
HZ value than the guest.