'Twas brillig, and Jeremy Nickurak at 23/08/10 15:40 did gyre and gimble: > No, that's not the right approach. This has been discussed many times on > this list. Just look at the archives, I'm not wasting hours of my life > reiterating what has already been discussed. > > A quick look around with google didn't indicate anything, except > instructions on how to enable dmix instead of/in-addition-to pulseaudio. > > Dmix seems to be the solution that alot of the pulseaudio critics > suggest as the silver bullet to audio problems... maybe the argument > about dmix can be iterated once more in a wiki page, so there's a more > permanent reference for that information? DMIX is very clever in itself, and in the absence of PA on a given system, I'd very much recommend it's usage. Layering one software mixing system on top of another however is a very silly idea, adding slowdowns and overhead to a pipeline that tries very hard to minimise locking and copying to avoid such latencies. Running two software mixers is not the solution to the architectural differences of the PA model to any existing one. Our goal is to ensure that only the the active user can access the sound hardware (and not just sound hardware but USB ports etc. too). The people advocating PA on top of dmix are those users who do not like that model and don't care about the consequences of what they are suggesting from an implementation perspective. As we discussed previously the pseudo session started for the GDM login prompt is the right approach here. There is always an "active" user, whether it's a real user or a pseudo login user or an "idle" user. It will then be up to the system administrator to configure various agents for such sessions. These agents can connect to sources of audio (e.g. mpd, a11y system etc.) and then be responsible for playing the actual audio via the pseudo session's own PA daemon. This requires a bit of a change to the various application stacks to allow this, but the benefits are clear and defined and the end goal of not allowing unauthorised access to sound hardware is maintained along with graceful handover in a multi-user, single seat system. Col -- Colin Guthrie gmane(at)colin.guthr.ie http://colin.guthr.ie/ Day Job: Tribalogic Limited [http://www.tribalogic.net/] Open Source: Mandriva Linux Contributor [http://www.mandriva.com/] PulseAudio Hacker [http://www.pulseaudio.org/] Trac Hacker [http://trac.edgewall.org/]
