At Tue, 28 Apr 2009 21:16:26 +0200, Claus Ilginnis wrote: > > > Hi everyone, > > I have a problem and I dont't know where to ask my questions anymore, so > I hope this mailing list can help me make progress with my problem.... > > I have a speaker set connected to an USB-Power-Plug (by which I can turn > the speakers on and off ) > > Now I want to detect, when the soundcard is in use and when not. > (to turn the speakers on when needed...) > (I am a C++ programmer so I can mess some things up) > > So my question is: > Which way is best to detect wheather my sound card is in use or not ? > Is there a general overview/documentation of the sound kernel modules > which describes the general relationship between them ? > What would you do ? The easiest way would be to check the status of device files, such as /dev/snd/*, whether any process opens it, e.g. via lsof command. But, this doesn't cover the case like an app such as a mixer applet which keeps opening the device but access only occasionally. Takashi _______________________________________________ Alsa-devel mailing list Alsa-devel@xxxxxxxxxxxxxxxx http://mailman.alsa-project.org/mailman/listinfo/alsa-devel
