[alsa-devel] [DAPM question] DAPM support for single input multiple outputs

[Qiao Zhou]

On 03/09/2015 04:53 PM, Lars-Peter Clausen wrote:
> On 03/09/2015 09:38 AM, Qiao Zhou wrote:
>> Hi Mark,
>>
>> I have one question and need your suggestion. Thanks in advance.
>>
>> In our DSP, one stream path is like this: There is one bit controlling
>> whether a signal A goes to A_out or B_out. That's the reverse case of
>> DAPM_MUX(multiple inputs, single output).
>>
>> One way is to use two switches but it seems not good since two switches
>> control the same bit. It's strange. Do you have any opinion about such
>> requirement support?
>
> There is currently no support for a demux. But it shouldn't be too hard to
> add one in the DAPM core, if you want to take a try at it.
>
> A demux would behave very similar to a mux, except that you'd reverse
> sources and sinks. The only thing that is a bit tricky is that we only have
> one control element per path and currently it always belongs to the sink.
> For a demux it needs to be long to the source. This means you can't have a
> mixer directly connected to the same path as a demux and the core needs to
> make sure that that doesn't happen.
I'll have a try to specially handle demux type. Thanks for the 
suggestions. BTW, is there plan to add demux support?
>
> - Lars
>


-- 

Best Regards
Qiao