On Tue, Jan 11, 2011 at 09:58:42AM -0500, Cole Robinson wrote: > On 01/11/2011 06:10 AM, Daniel P. Berrange wrote: > > On Tue, Jan 11, 2011 at 11:46:14AM +0100, Gerd Hoffmann wrote: > >> On 01/10/11 18:19, Cole Robinson wrote: > >>> In QEMU, the card itself is a PCI device, but it requires > >>> -device hda-output in order to actually get sound to the host. AIUI this > >>> is just HDA configuration and does not require stable addressing, so > >>> is not presently represented in the XML. > >> > >> It isn't that simple. There are actually multiple devices involved. > >> Each audio codec (yes, there can be multiple of these, up to 15) is > >> connected via HDA Link to the pci controller. Each audio codec has > >> a codec address (HDA bus property: cad=[0..14]). > >> > >> So you can specify "-device intel-hda -device hda-duplex -device > >> hda-output" and the guest has multiple audio devices. Win7 even > >> handles this correctly, whereas alsa uses only the first codec it > >> finds (lowest codec address). Not that this buys you much today, > >> qemu mixes all channels together before sending them off to the > >> hosts sound system, i.e. you don't see a stream per sound card in > >> pulseaudio. That might change in the future though. > >> > > > > So 'intel-hda' should really be considered as a controller, > > and hda-output' & 'hda-duplex' are the things to be treated > > as devices in the guest config. > > > > This suggests a setup more like the one we did for virtio-serial > > where we'd invent a new address type for codecs, and have XML > > looking something like > > > > <controller type='hda' model='ich6'> > > <address type='pci' domain='0x0000' bus='0x00' slot='0x0a' function='0x0'/> > > </controller> > > <sound model='hda-output'> > > <address type='hda' codec='0'/> > > </sound> > > <sound model='hda-duplex'> > > <address type='hda' codec='1'/> > > </sound> > > > > Sounds good, though I think doing > > <sound model='hda' mic="on|off"/> > > would be preferable from a UI perspective, since it sounds like that's > the only differentiating factor (or maybe use 'duplex' or 'input' etc.). > Does that sound okay? The problem with mic=on|off is that it only works for the current case of choosing hda-output vs hda-duplex. It can't cope with the scenario where QEMU adds more codecs, which are unrelated to the microphone state, Gerd mentioned might well happen Regards, Daniel -- libvir-list mailing list libvir-list@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/libvir-list