'Twas brillig, and Tanu Kaskinen at 13/06/11 17:32 did gyre and gimble: > On Sun, 2011-06-12 at 19:59 +0800, Lin, Mengdong wrote: >> Could someone tell me how to use "sco_sink" and "sco_source" in the >> bluetooth device module? >> >> Because of hardware restriction, our bluetooth driver cannot handle >> HSP data transport. We want use an ALSA device's sink and source for >> BT HSP transport. It seems that by passing parameters to initialize >> the Bluetooth discover and device module, a bluetooth device can use >> external "sco-sink" and "sco-source" for HSP data transport. >> >> My questions: >> >> - I can set the ALSA sink & source as the "sco-sink" and >> "sco-source", right? If yes, how can I set "sco-source" and "sco-sink" >> names as the parameter to load Bluetooth discover module in the >> default script for my platform? > > Just pass the sco-source and sco-sink arguments to > module-bluetooth-discover. I noticed that the module still had some > instances of #ifdef NOKIA left, so you'll either have to compile > Pulseaudio with NOKIA defined, or apply the patch I just sent to the > mailing list that removes the ifdefs. Nice, thanks. >> - Since "sco-sink" and "sco-source" are not dynamically >> created, so I cannot routing inputs/outputs to them by hook the >> "SINK-PUT" or "SOURCE-PUT" event, right? > > Right. It would be good to make it possible to load those dynamically, > though. One possibility would be to load module-alsa-sink/source from > module-bluetooth-device when the hsp profile is activated. Or if the > card is managed by module-alsa-card, then module-bluetooth-device could > switch the card profile so that the appropriate devices get loaded. I think the profile switching is a good idea. I think Amanda (or other folk on this list recently) were working on auto-profile switching support based on module-intended-roles, so this would tie in nicely IMO. Need to get a list of the various external patches in this regards together so we don't reinvent things :D >> - When can I move sink inputs or source outputs to the >> "sco-sink" and "sco-source"? Their state changes outside of the >> Bluetooth device. How are their state change synchronized with BT >> headset connection and disconnection? In BT device module, I saw both >> "start_thread" and state change hook of "sco-sink" and "sco-source" >> call "sco_over_pcm_state_update" to setup data transport. So they can >> change to IDLE state at any time? > > I don't know the module-bluetooth-device code terribly well, but I'd > guess that when the card profile is set to hsp, the module somehow sets > things up so that the sco-sink and sco-source are ready to process > streams. So maybe the routing logic should connect to the > PA_CORE_HOOK_PROFILE_CHANGED hook? Sounds reasonable. >> - Has the usage "sco-sink" and "sco-source" been verified on >> any platform? > > Yes, like Luiz said, Maemo devices use it. Maemo doesn't use the vanilla > Pulseaudio upstream version, though, and I expect that the current git > version won't work out-of-the-box. There's not much missing - the only > thing that comes to my mind is one assertion in sink.c, if I remember > correctly, that has been relaxed, because otherwise the HSP volume setup > doesn't work. > > module-bluetooth-device replaces the alsa sink's volume callbacks with > its own versions, and that causes problems because the alsa sink thinks > that it doesn't have hardware volume control, yet the volume callbacks > are set which should happen only when hw volume control is available. > I'd solve this so that module-bluetooth-device puts the callback > function pointers available in the pa_core.shared hashmap, and > module-alsa-sink gets the keys to the hashmap as module arguments and > then fetches the callbacks from the hashmap using those keys. That way > module-alsa-sink is aware of that in fact it does support hardware > volume control, it just does it in a different way than usual. Hmm, I see what you mean. It's not really particularly pretty, but probably the easiest way around it. Col -- Colin Guthrie gmane(at)colin.guthr.ie http://colin.guthr.ie/ Day Job: Tribalogic Limited [http://www.tribalogic.net/] Open Source: Mageia Contributor [http://www.mageia.org/] PulseAudio Hacker [http://www.pulseaudio.org/] Trac Hacker [http://trac.edgewall.org/]
