Re: [libvirt] [PATCH 3/6] qemu: explicitly disable audio if there is no sound device

On Tue, Nov 21, 2017 at 11:24:06 +0000, Daniel Berrange wrote: > On Tue, Nov 14, 2017 at 02:45:08PM +0100, Pavel Hrdina wrote: > > If there is no sound device configured for the guest we can disable the > > audio output because hot-plugging sound devices isn't supported. > > Are you sure about that. While libvirt may not have wired up ability to > hotplug sound devices, I'm pretty sure that QEMU is able to hotplug > them. At least the USB sound card should allow hotplug in qemu, so I agree with this... On the other hand the output should be a property which can be configured individually for every sound card. I think it's desirable to have a soundcard dedicated to one output method and a second one for a different output method and let the guest OS decide on which cards the sound will play. > Ff libvirt forceably disables the audio backend, now, and then future > libvirt enables the pre-existing QEMU support for hotplug, existing VMs > will be doomed. > > IOW, I don't think this patch is desirable. We could allow hotplug only if qemu will allow to specify the sound output per-soundcard which would avoid this problem.