[alsa-devel] codec power question
Hi,
In some cases the audio stream is kept ON and idle by application. In that case codec is also ON. Is there a mechanism where DAPM can detect this idle condition and turn off the idle widgets or turn of the codec BIAS
On Tue, 2011-03-15 at 15:10 +0530, Koul, Vinod wrote:
Hi,
In some cases the audio stream is kept ON and idle by application. In that case codec is also ON. Is there a mechanism where DAPM can detect this idle condition and turn off the idle widgets or turn of the codec BIAS
Oops messed up Marks email, fixed now...
On Tue, Mar 15, 2011 at 03:10:23PM +0530, Koul, Vinod wrote:
In some cases the audio stream is kept ON and idle by application. In that case codec is also ON. Is there a mechanism where DAPM can detect this idle condition and turn off the idle widgets or turn of the codec BIAS
If this is happening it's a framework bug - if there are no active audio streams through the device then it should be brought down to the lowest power state. The application doesn't have any direct control over the CODEC power except by configuring audio streams. Can you provide any more details on how this happens?
Note that for playback streams there's a delay before things are powered down to avoid delays, pops and clicks when doing things like changing tracks. By default the delay is 5s.
On Tue, 2011-03-15 at 17:00 +0530, Mark Brown wrote:
On Tue, Mar 15, 2011 at 03:10:23PM +0530, Koul, Vinod wrote:
In some cases the audio stream is kept ON and idle by application. In that case codec is also ON. Is there a mechanism where DAPM can detect this idle condition and turn off the idle widgets or turn of the codec BIAS
If this is happening it's a framework bug - if there are no active audio streams through the device then it should be brought down to the lowest power state. The application doesn't have any direct control over the CODEC power except by configuring audio streams. Can you provide any more details on how this happens?
In andriod, flinger opens the streams at boot and keeps them ON, and doesn't close the stream when in idle. Since the stream in ON, codec consumes lot of power, I was wondering if we have something in asoc to detect this kind of state and do much better power control.
On Tue, Mar 15, 2011 at 05:57:27PM +0530, Koul, Vinod wrote:
In andriod, flinger opens the streams at boot and keeps them ON, and doesn't close the stream when in idle. Since the stream in ON, codec consumes lot of power, I was wondering if we have something in asoc to detect this kind of state and do much better power control.
Ah, this is just a plain userspace bug in the default ALSA thing that went up on the Android git - there's no way sensible way to figure out that userspace is playing silence because it's being silly.
The Nexus S libaudio does a better job here though it has its own issues due to the integration with the non-mainline CODEC driver they're using.
participants (2)
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Koul, Vinod -
Mark Brown