Gerd Hoffmann <kra...@redhat.com> writes: > Hi, > >> Only pulse and the spice audio backends set VOICE_VOLUME_CAP. >> >> Impact on users isn't obvious to me. > > It offloads volume control to the audio backend, i.e. it will be done by > pulseaudio/spice-client instead of mixemu. > >> Questions (not just for you, Bandan): >> >> 1. Why is CONFIG_MIXEMU off by default? > > malc wants it this way because mixemu eats cpu time. > >> 2. Why do we bother providing these devices when CONFIG_MIXEMU off? >> >> Why would anyone want hda audio devices without a mixer? Why >> wouldn't anyone who wants hda audio devices also want CONFIG_MIXEMU >> enabled? > > It'll actually work just fine with HDA. The guest figures there is no > volume control and will fallback to do volume control in software then. > Net effect is that the audio sample processing to change volume is done > by the guest instead of mixemu, so you don't actually save cpu time by > turning off mixemu ...
I don't doubt it works, I doubt anybody would want the software mixing done in the guest instead of mixemu so badly that he wants to use a special device that makes that possible. > I think AC97 has broken volume control with CONFIG_MIXEMU=n, because the > guest tries to use the non-functional volume controls. > > So, yes, for serious sound support you want CONFIG_MIXEMU=y. Which brings me back to question 1: why is non-serious sound support the default?
