Re: [libvirt] [PATCH] qemu: sound: Support intel 'hda' model

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