[pve-devel] Audio support, dummy/none

[Gilles Pietri]

Hi!

Happy new year to everyone, especially the devs working on Proxmox, it's
still awesome in 2021 ;)

I'm interested in replicating a qemu audio setup that uses the dummy
driver (called "none") on Proxmox, but the enum $audio_fmt
(PVE/QemuServer.pm) for drivers only contains spice as a choice, which
is all nice, but a bit restrictive!

Since this is used only (?) to generate the audio conf (through
conf_has_audio), which generate the audio devices through audio_devs,
which in turn generates both the -device param and the -audiodev
backend,id=xxx, it seems there wouldn't be any side effect if we fed
"none" instead of spice, as the id param is valid and works the same here.

I haven't tried patching that, but it might be that this would boil down to:

diff --git a/PVE/QemuServer.pm b/PVE/QemuServer.pm
index bca5669..54278e5 100644
--- a/PVE/QemuServer.pm
+++ b/PVE/QemuServer.pm
@@ -211,7 +211,7 @@ my $audio_fmt = {
     },
     driver =>  {
        type => 'string',
-       enum => ['spice'],
+       enum => ['spice', 'none'],
        default => 'spice',
        optional => 1,
        description => "Driver backend for the audio device."

And maybe, if we want to go further, we may want a bit of documentation
also, maybe on the wiki… Also, though it's not my usecase atm, it might
be interesting to add others backends as well, like alsa or pa. It was
mentionned here:
https://forum.proxmox.com/threads/audiodev-driver-pa-support.62317/#post-285020

However that will require second level options for the audio backends,
which are not supported as it's coded.

Cheers,

Gilou