Mark Brown wrote: > On Thu, Dec 17, 2009 at 09:47:59AM +0100, Michael Trimarchi wrote: > > >> I have a simple question is the general behavior that an alsa device >> start to drain power >> when it starts to play sound or start to recording. What happen if there >> is an external amplifier >> connect to sound device? >> > > In general any audio component is going to draw more power if there is a > signal going through it than if it's idle. This is true regardless of > how the audio subsystem is split in terms of physical chips. > > What are you trying to find out here? > > As reported by the datasheet the LM4853 has a bias circuitry shutdown. This shutdown function is activated by applying a logic high to the SHUTDOWN pin. This pin as command by the static int lm4853_event(struct snd_soc_dapm_widget *w, struct snd_kcontrol *k, int event) in gta02. I don't put any debug stuff there but I suppose if I open the device with and asound.conf that set the value to true of the Stereo Out this event is called. Is it right? Michael _______________________________________________ Alsa-devel mailing list Alsa-devel@xxxxxxxxxxxxxxxx http://mailman.alsa-project.org/mailman/listinfo/alsa-devel