* Sound detection @ 2007-01-21 12:39 Andreas Corneliussen 2007-01-25 12:36 ` Takashi Iwai 0 siblings, 1 reply; 6+ messages in thread From: Andreas Corneliussen @ 2007-01-21 12:39 UTC (permalink / raw) To: alsa-devel 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. Any help would be appreciatet. Regards Andreas ------------------------------------------------------------------------- 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 ^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: Sound detection 2007-01-21 12:39 Sound detection Andreas Corneliussen @ 2007-01-25 12:36 ` Takashi Iwai 2007-01-25 16:03 ` Liam Girdwood 0 siblings, 1 reply; 6+ messages in thread From: Takashi Iwai @ 2007-01-25 12:36 UTC (permalink / raw) To: Andreas Corneliussen; +Cc: alsa-devel 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. Maybe the easiest solution is to route the all audio I/O through a sound server and let the sound server do the proper power management. Alternatively, you can modify the dmix and dsnoop plugins so that some power-management codes can be called at the first-open and the last-close. In both cases, the power-off shouldn't be sent too immediately after the last close. Otherwise you may get often click noises by bad apps that open/close too frequently just for reset, etc. 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 ^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: Sound detection 2007-01-25 12:36 ` Takashi Iwai @ 2007-01-25 16:03 ` Liam Girdwood 2007-01-25 16:09 ` Takashi Iwai 0 siblings, 1 reply; 6+ messages in thread From: Liam Girdwood @ 2007-01-25 16:03 UTC (permalink / raw) To: Andreas Corneliussen; +Cc: Takashi Iwai, alsa-devel 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. http://opensource.wolfsonmicro.com/~lg/asoc/ Liam ------------------------------------------------------------------------- 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 ^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: Sound detection 2007-01-25 16:03 ` Liam Girdwood @ 2007-01-25 16:09 ` Takashi Iwai 2007-01-25 16:21 ` Liam Girdwood 0 siblings, 1 reply; 6+ messages in thread From: Takashi Iwai @ 2007-01-25 16:09 UTC (permalink / raw) To: Liam Girdwood; +Cc: Andreas Corneliussen, alsa-devel 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? I supposed that the power-management stuff isn't built in the driver itself... 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 ^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: Sound detection 2007-01-25 16:09 ` Takashi Iwai @ 2007-01-25 16:21 ` Liam Girdwood 2007-01-25 16:32 ` Takashi Iwai 0 siblings, 1 reply; 6+ messages in thread From: Liam Girdwood @ 2007-01-25 16:21 UTC (permalink / raw) To: Takashi Iwai; +Cc: Andreas Corneliussen, alsa-devel 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) Liam ------------------------------------------------------------------------- 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 ^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: Sound detection 2007-01-25 16:21 ` Liam Girdwood @ 2007-01-25 16:32 ` Takashi Iwai 0 siblings, 0 replies; 6+ messages in thread From: Takashi Iwai @ 2007-01-25 16:32 UTC (permalink / raw) To: Liam Girdwood; +Cc: Andreas Corneliussen, alsa-devel 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 ^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2007-01-25 16:32 UTC | newest] Thread overview: 6+ messages (download: mbox.gz follow: Atom feed -- links below jump to the message on this page -- 2007-01-21 12:39 Sound detection Andreas Corneliussen 2007-01-25 12:36 ` Takashi Iwai 2007-01-25 16:03 ` Liam Girdwood 2007-01-25 16:09 ` Takashi Iwai 2007-01-25 16:21 ` Liam Girdwood 2007-01-25 16:32 ` Takashi Iwai
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