Re: [libvirt] [PATCH 4/6] conf: introduce <output> element for <sound> devices

On Tue, Nov 14, 2017 at 02:45:09PM +0100, Pavel Hrdina wrote: > So far it was not possible to specify how the audio output from guest > should be presented to host/users. Now it will be possible to do so > via <output> element for <sound> device where you specify the output > "type". > > Signed-off-by: Pavel Hrdina <phrdina(a)redhat.com&gt; > --- > docs/formatdomain.html.in | 9 +++++++ > docs/schemas/domaincommon.rng | 14 ++++++++++ > src/conf/domain_conf.c | 61 +++++++++++++++++++++++++++++++++++++++++++ > src/conf/domain_conf.h | 14 ++++++++++ > src/libvirt_private.syms | 2 ++ > 5 files changed, 100 insertions(+) > > +static int > +virDomainSoundOutputParseXML(xmlXPathContextPtr ctxt, > + virDomainSoundDefPtr sound) > +{ > + int ret = -1; > + char *type = NULL; > + int typeVal; > + xmlNodePtr *outputNodes = NULL; > + int noutputs; > + > + noutputs = virXPathNodeSet("./output", ctxt, &outputNodes); > + if (noutputs < 0) > + return -1; > + > + if (noutputs > 1) { > + virReportError(VIR_ERR_CONFIG_UNSUPPORTED, "%s", > + _("sound device can have only one output configured")); > + goto cleanup; > + } The implication of this is that if you have multiple display backends enabled only one of them will ever be selectable as the audio backend. It is not unreasonable to consider that audio should go to all backends, or depending on which is in use. eg if QEMU has SDL + SPICE enabled, audio could conceptually go to SDL by default, and get dynamically switched to SPICE whenver there is a SPICE client actively connected. This is a risk of trying to design a configuration approach for this, without us asking QEMU to consider their corresponding design possibilities