[alsa-devel] Exporting playback and capture capability to user space

Rajeev kumar rajeev-dlh.kumar at st.com
Mon Nov 21 06:49:10 CET 2011

Hello Mark

Could you please help me by answering these questions?

Best Regards

On 11/17/2011 7:05 PM, Rajeev kumar wrote:
> Hello Mark
> I have a single codec with playback and capture capability. We are using
> it for different i2s controller. Below are the details for that.
> case 1: I2S controller-1: with playback and capture capability
> case 2: I2S controller-2: with playback capability only
> case 3: I2S controller-3: with capture capability only.
> We are registering all the I2S controller with there respective capability.
> In command 'aplay -l' or 'cat /proc/asound/pcm', among playback devices,
> capture device is also listed. This is true in case-1 but for case-2 and
> case-3 also it is showing the same behavior. According to my
> understanding it should not show the list of all devices i.e. in case of
> controller having playback capability it should show only playback
> devices not capture devices and vice versa. Please correct me if I am
> wrong.
> So my questions are
> 1. How to separate playback and capture devices in case-2 and case-3.
> Are we need to register different codec for different i2s controller?
> 2. Is it codec capability only which is exported to user space ?
> Best Regards
> Rajeev

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