How to do pause/resume in ALSA application

How to do pause/resume in ALSA application

[Aggarwal, Anuj]

Hi, 

 

I am using the snd_pcm_pause API in my application but it is returning
error: Invalid argument. I am passing the PCM handle of the playback
stream which I opened earlier and using to play a WAV file. Although I
am able to hear the WAV file correctly, I am not able to pause. I
checked whether the pause functionality is supported, using
snd_pcm_hw_params_can_pause() and it returned me success.

 

Any help is welcome.

 

Thanks & Regards,

Anuj Aggarwal

Re: How to do pause/resume in ALSA application

[Clemens Ladisch]

Aggarwal, Anuj wrote:
> I am using the snd_pcm_pause API in my application but it is returning
> error: Invalid argument.

This indicates that the driver (or some PCM plugin) does not support
pausing.

> I checked whether the pause functionality is supported, using
> snd_pcm_hw_params_can_pause() and it returned me success.

This is a bug.  What device name did you use when opening the device,
and which driver are you using?


Regards,
Clemens

Re: How to do pause/resume in ALSA application

[Aggarwal, Anuj]

Clemens,

Are you suggesting a bug in the driver or in the library? 

I passed "plughw:0,0" as the device name. We have our own driver for the
audio codec, written as per the ALSA framework.  

Thanks & Regards,
Anuj Aggarwal
 
 

-----Original Message-----
From: alsa-devel-bounces@alsa-project.org
[mailto:alsa-devel-bounces@alsa-project.org] On Behalf Of Clemens
Ladisch
Sent: Wednesday, March 05, 2008 9:23 PM
To: Aggarwal, Anuj
Cc: alsa-devel@alsa-project.org; suresh.raj@gmail.com
Subject: Re: [alsa-devel] How to do pause/resume in ALSA application

Aggarwal, Anuj wrote:
> I am using the snd_pcm_pause API in my application but it is returning
> error: Invalid argument.

This indicates that the driver (or some PCM plugin) does not support
pausing.

> I checked whether the pause functionality is supported, using
> snd_pcm_hw_params_can_pause() and it returned me success.

This is a bug.  What device name did you use when opening the device,
and which driver are you using?


Regards,
Clemens
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Re: How to do pause/resume in ALSA application

[Clemens Ladisch]

(please don't top-post)
Aggarwal, Anuj wrote:
> Are you suggesting a bug in the driver or in the library?

Yes.

> I passed "plughw:0,0" as the device name.

The plug plugin doesn't do funny things with pausing, so the bug must
be in the driver.

> We have our own driver for the audio codec, written as per the ALSA
> framework.

I'd guess that the SNDRV_PCM_INFO_PAUSE flag is set, but that the
trigger callback doesn't implement SNDRV_PCM_TRIGGER_PAUSE_PUSH/RELEASE.


HTH
Clemens