On Tue, Nov 21, 2017 at 01:21:26PM +0100, Pavel Hrdina wrote: > On Tue, Nov 21, 2017 at 12:09:54PM +0000, Daniel P. Berrange wrote: > > On Tue, Nov 21, 2017 at 01:02:05PM +0100, Peter Krempa wrote: > > > On Tue, Nov 21, 2017 at 11:48:20 +0000, Daniel Berrange wrote: > > > > On Tue, Nov 21, 2017 at 12:44:44PM +0100, Peter Krempa wrote: > > > > > On Tue, Nov 21, 2017 at 11:24:06 +0000, Daniel Berrange wrote: > > > > > > 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. > > > > > > > > I agree that having ability to configure distinct outputs per sound card > > > > might be useful, I don't think it is a blocking feature for hotplugging > > > > sound cards. ie, there's no reason why a user should not be able to > > > > unplug their current sound card, and plug in a new sound card for a > > > > running guests - they would only ever have 1 sound card present at > > > > a time in that scenario, so distinct outputs is not a requirement > > > > for that usecase. > > > > > > While not a requirement, mandating that new features are available only > > > with new software sometimes saves a lot of headaches. I would not > > > mind if sound device hotplug will be supported only when specific > > > outputs can be selected when adding the sound card and would not work > > > without that. > > > > > > Unfortunately qemu does not yet support this and I don't think that they > > > will any soon. > > > > Agreed, and the most interesting thing for multiple audio cards is > > probably multi-seat support, which wouldn't need choosing between > > different backends, instead choosing different spice/vnc instances. > > > > Basically, I think this patch should be dropped. > > Ok, I don't mind dropping this patch. At least it pointed out that > QEMU is design is broken. This patch only affects use case where > the domain is started without any sound device and I personally don't > care if the audio output will be basically random unless you have > spice graphic configured. > > However, if we enabled hot-plugging sound device we need to make sure > that we don't allow configuring sound output until we have a decent way > how to configure it. Agreed - that's pretty much why i never exposed sound backend in the XML and instead hardcoded it with optional override in qemu.conf when first doing this Regards, Daniel -- |: https://berrange.com -o- https://www.flickr.com/photos/dberrange :| |: https://libvirt.org -o- https://fstop138.berrange.com :| |: https://entangle-photo.org -o- https://www.instagram.com/dberrange :| -- libvir-list mailing list libvir-list@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/libvir-list
