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