At Thu, 25 Jan 2007 16:21:43 +0000, Liam Girdwood wrote: > > On Thu, 2007-01-25 at 17:09 +0100, Takashi Iwai wrote: > > At Thu, 25 Jan 2007 16:03:29 +0000, > > Liam Girdwood wrote: > > > > > > On Thu, 2007-01-25 at 13:36 +0100, Takashi Iwai wrote: > > > > At Sun, 21 Jan 2007 13:39:35 +0100, > > > > Andreas Corneliussen wrote: > > > > > > > > > > Hi > > > > > I've just build a mediacenter, and is about to construct an hifi > > > > > amplifier for it. Therefore i would like to know a way to make alsa > > > > > detect when nothing is playing at the output, and then run a external > > > > > command. And detect when something has started playing at the output, > > > > > and run an external command before any output is generatet. > > > > > This I would like to do, because I then could make an interface between > > > > > the amplifier and the computer to make sure that it does not use anymore > > > > > standbypower than needed. > > > > > > > > It's an interesting question. Currently, there is no good framework > > > > for such a functionality, so you need to build something new. > > > > > > > > > > Fwiw, the Dynamic Audio Power Management code in ASoC (Alsa for SoC > > > devices) does this very thing. Please feel free to have a look and take > > > code if required. > > > > But it doesn't communicate with the user-space, right? > > Your right, it only powers on board components and can't communicate > with user-space atm. > > > I supposed that the power-management stuff isn't built in the driver > > itself... > > > > The codec and machine power maps are in the driver, but it's controlled > via the ASoC core (and ultimately via alsa-lib) Yes, I understand the ASoC design :) Just to clarify: My comment above refers the fact that the power-mangement outside of the sound-chip/controller might be necessary to be accessed from the outside, preferablly from a user-space tool. I just guessed this case is like so. But, it might be, of course, much easier to do in the driver code depending on the hardware design. Takashi ------------------------------------------------------------------------- Take Surveys. Earn Cash. Influence the Future of IT Join SourceForge.net's Techsay panel and you'll get the chance to share your opinions on IT & business topics through brief surveys - and earn cash http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV _______________________________________________ Alsa-devel mailing list Alsa-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.sourceforge.net/lists/listinfo/alsa-devel
