topic Re: Alsa Library: Error opening PCM playback device in i.MX Processors

Alsa Library: Error opening PCM playback device

Swamy — Fri, 11 Nov 2011 11:44:47 GMT

Hi,

I am running Navigation application, I am not able to hear the sound on this. It is looking for ALSA-Lib which I have selected in the LTIB-drivers.

Navigation is my application. It is not part of the LTIB.

I get following error when I run the navigation application.

Error opening PCM playback device: -6, No such device or address
Retrying..
ALSA lib pcm.c:2166:(snd_pcm_open_conf) symbol _snd_pcm_plug_open is not defined
inside [builtin]

This is the output of $ cat /proc/asound/cards

root@freescale /mnt/usb$ cat /proc/asound/cards

0 [imx3stack      ]: SGTL5000 - imx-3stack
                      imx-3stack (SGTL5000)
1 [imx3stackspdif ]: mxc spdif - imx-3stack-spdif
                      imx-3stack-spdif (mxc spdif)

I am attaching viewer.c(application file) and audio.c(alsa driver configuration)

Please let me where I am going wrong. Also I am attaching alsa-lib.spec file.

Kindly help.

Regards,

Swamy

Original Attachment has been moved to: 538-audio.c

Original Attachment has been moved to: 539-alsalib.spec

Original Attachment has been moved to: 537-viewer.c

Re: Alsa Library: Error opening PCM playback device

daiane_angolini — Fri, 11 Nov 2011 14:25:50 GMT

Does sound works with aplay?

You are using iMX53 SMD, isn´t it?

Re: Alsa Library: Error opening PCM playback device

Swamy — Fri, 11 Nov 2011 14:32:15 GMT

Hi Daiane Angolini,

Yes I am using IMX53 SMD.

Yes, If I try the "aplay" command independently, the sound works for me

root@freescale /mnt/usb$ aplay -D hw:0,0 xpstartu.wav
Playing WAVE 'xpstartu.wav' : Signed 16 bit Little Endian, Rate 22050 Hz, Stere

Please suggest

Regards,
Swamy

Re: Alsa Library: Error opening PCM playback device

daiane_angolini — Fri, 11 Nov 2011 18:51:11 GMT

From your audio.c:

retVal = snd_pcm_open( &pcm_playback, playback_device, SND_PCM_STREAM_PLAYBACK, SND_PCM_NONBLOCK);
        //retVal = snd_pcm_open( &pcm_playback, "default", SND_PCM_STREAM_PLAYBACK, SND_PCM_NONBLOCK);
        if (retVal != 0)
        {

From aplay's source code: (alsa-utils-1.0.11rc2/aplay/aplay.c)

err = snd_pcm_open(&handle, pcm_name, stream, open_mode);
    if (err < 0) {
        error(_("audio open error: %s"), snd_strerror(err));
        return 1;
    }

pcm_name is "default" (Why your "default" line is comment out?)

and open_mode is SND_PCM_NONBLOCK only in case you specify it from command line, otherwise it's 0, can you try with 0?

Re: Alsa Library: Error opening PCM playback device

Swamy — Sat, 12 Nov 2011 18:08:53 GMT

Hi Daiane Angolini,

Thanks for the reply. I am on vacation this Monday. I shall try out this on Tuesday in office and let you know.

Regarding the commented line, I was just trying by giving default instead of playback_device. However it did not work for me, hence I commented back and retained the original code.

//retVal = snd_pcm_open( &pcm_playback, "default", SND_PCM_STREAM_PLAYBACK, SND_PCM_NONBLOCK);

Regards,

Swamy

Re: Alsa Library: Error opening PCM playback device

Swamy — Tue, 15 Nov 2011 06:39:57 GMT

Hi Daiane Angolini,

I made the following changes as you said...But no luck..

retVal = snd_pcm_open( &pcm_playback, playback_device, SND_PCM_STREAM_PLAYBACK, SND_PCM_NONBLOCK);

retVal = snd_pcm_open( &pcm_playback, playback_device, SND_PCM_STREAM_PLAYBACK, 0);

The Navigation device which I have is a USB device. Do I need to configure the USB device for Audio...something like that in LTIB?

Please suggest.

Regards,

Swamy