Re: Device creation order

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



'Twas brillig, and Jaroslav Kysela at 03/04/09 08:31 did gyre and gimble:
> Lennart, why you need to enumerate all devices per card at one time? I 
> think that having mixer access plus one PCM device is enough for minimal 
> configuration for PA.

PA now has a concept of "cards". The hal-detect module will load the 
module-alsa-card module which in turn will probe the "card" in question 
to see what it supports.

As alsa does not export information such as what parts of the card can 
be used concurrently, the module-alsa-card has to be able to probe e.g. 
5.1 output + stereo input to see if it works. From this probing, we can 
build up a list of "Card Profiles" so we can let the user pick their 
configuration[1] they want. When a user changes configuration, it will 
take care of loading the individual module-alsa-sink and 
module-alsa-source modules for dealing with the actual output/input.

Hope that explains why the whole card is needed rather than just a 
single PCM.

Col

See:
http://colin.guthr.ie/development/configuring-card-profiles-in-pulseaudio.html

-- 

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/]

_______________________________________________
Alsa-devel mailing list
Alsa-devel@xxxxxxxxxxxxxxxx
http://mailman.alsa-project.org/mailman/listinfo/alsa-devel

[Index of Archives]     [ALSA User]     [Linux Audio Users]     [Kernel Archive]     [Asterisk PBX]     [Photo Sharing]     [Linux Sound]     [Video 4 Linux]     [Gimp]     [Yosemite News]

  Powered by Linux