Is there any chance I can subscribe to audio-discuss? Or should audio-discuss be moved to opensolaris.org?
Thanks, Brian On Jan 20, 2008 10:31 PM, Frank Che <Frank.Che at sun.com> wrote: > I'm sponsoring this fast track for Freeman Liu and the audio team. > The requested binding is minor. The timer is set to 01/29/2008. > > ------------------------------------------------------------------------------------------------ > > 4.Technical Description > > This project is phase 1 of the umbrella project described in > "Open Sound System (OSS) for Solaris" (PSARC 2007/238) > There are two main goals of this phase. One is to integrate OSS high > definition audio driver "hdaudio" into Solaris to support the most > popular audio hardware. The other goal is to keep SADA > (Solaris Audio Driver Architecture) compatibility so that there will > be no regression for the current SADA applications. > > Theoretically, all the HD audio hardware will be supported. We will test > the ones supported by SADA HD audio driver to prevent regression. Several > other popular codecs will also be covered. > > The SADA compatibility is accomplished by an emulation layer named > "sadasupport". It is a pseudo SADA audio driver which provides SADA > interface to upper level. From the applications' point of view, it > is not different from other SADA drivers. On the other hand, it does > not operate the hardware directly. Instead, it accesses the device file > provided by the lower level OSS drivers through ldi interface. The > following diagram illustrates the relations between SADA framework, > sadasupport, OSS framework and OSS driver where there is a HD audio > hardware in the system > > |-------------| > User level |app1,app2 ...| > |------+------| > |(1) > | > |-----+----| |--------| > -------------------|/dev/audio|-----------------|/dev/dsp|------------------ > |-----+----| |-+--+---| > |(2) (4) | | > Kernel level | +--------------------+ |(5) > | | | > |--------------|(3)|-----+---+-| |---+---|(6)|-------------| > |SADA framework+---+sadasupport| |hdaudio+---+OSS framework| > |--------------| |-----------| |---+---| |-------------| > |(7) > |---+----| > |HD audio| > |hardware| > |--------| > > * (1),(2) Applications make audio requests through /dev/audio, > which is exported by sadasupport. > * (3) Sadasupport turns to SADA framework to fulfill the requests > * (4),(5) Sadasupport access hdaudio driver by ldi interface when > it needs service from hdaudio driver to complete the requests > * (6),(7) Hdaudio turn to OSS framework to fulfill the requests > and operate the hardware when needed. > > In phase 1, the device file "/dev/dsp" provided by OSS drivers is a > project private interface and only root user is able to access it. > No new interface will be published in this phase. Although HD audio > driver is replaced by OSS hdaudio driver, other SADA drivers will not > be replaced in phase 1. Drivers of the two different frameworks can work > together. SADA framework will not be removed, either. Detailed information > of SADA can be found in man pages: audio(7I), mixer(7I) and > audio_support(7I). > > Summarily, we use OSS hdaudio driver to support HD audio hardware > and use sadasupport to maintain SADA compatibility. > > During the discussion of the umbrella case, the issue of latency has > been brought up. In this context, latency means the time gap between > the time hardware/driver is changed by other applications or by external > events and the time when applications sense it. And it should be > achieved without high CPU usage. It can be achieved by leverage > feature provided by SADA interface. Since SADA interface will be kept, > latency issues is addressed naturally. Consensus was reached during > the offline discussion. > > Here is the list of all kernel module and driver files: > osscommon > osscore > osscore.conf > sadasupport > sadasupport.conf > vmix > vmix.conf > hdaudio > hdaudio.conf > > Some of the tunables provided by the .conf files are for changing > some aspect of the OSS system. But the default value is suitable > in most case and they rarely need to be changed. Other tunable are > for debugging. > > All these files and the tunables are of project private stability in this > phase. They might be changed in the following phases. > > 5. Reference Documents: > > Open Sound System (OSS) for Solaris (PSARC 2007/238). > http://opensolaris.org/os/project/opensound > > > > > _______________________________________________ > opensolaris-arc mailing list > opensolaris-arc at opensolaris.org > -- - Brian Gupta http://opensolaris.org/os/project/nycosug/
