[alsa-devel] Playback issue while recording simultaneously

[Mohan Prasath Ramamoorthy]

Hi Pierre-Louis,

Thank you for your quick response.

Shall I know what does the below error mean?

aplay: pcm_write:1940: write error: Input/output error

On Fri, Dec 6, 2019 at 9:21 PM Pierre-Louis Bossart
<pierre-louis.bossart at linux.intel.com> wrote:
>
>
>
> On 12/5/19 11:22 PM, Mohan Prasath Ramamoorthy wrote:
> > Dear All,
> >
> > We are working on external modules of microphone and speaker and we
> > are using the kernel version 3.10.96
>
> wow, that is one ancient kernel EOL'ed in 2017...
>
> >
> > We are recording with commands like arecord and aplay for recording
> > and playback respectively.
> >
> > While doing the below experiments we could able to observe an issue as below,
> >
> > 1. With only recording and not playback we haven't faced any issues.
> > 2. With only playback and not recording we haven't faced any issues.
> >
> > 3. By starting an infinite recording in the background and by doing a
> > playback of the audio file(30seconds, the sampling rate of 22050, the
> > channel is stereo), after some iterations, we are facing a below error
> > and we could not able to listen to the audio.
> >
> > Error: aplay: pcm_write:1940: write error: Input/output error
> >
> > Below are the respective commands for recording and playback,
> >
> > 1. arecord -D hw:0,0 -c 2 -f s16_le -r 8000 /home/ubuntu/mic_testing.wav &
> > 2. aplay -D hw:0,3 audio_22k_c2.wav
> >
> > But when the issues come, we just stopped recording and restarted the
> > recording in the background. After this, the playback is working fine.
> >
> > Also, during the issue came, we have checked for the below properties,
> >
> > 1. I2S has been enabled. Checked under the file:
> > /sys/kernel/debug/clock/clock_tree
> > 2. Driver callbacks have been called. (Checked with the kernel logs[dmesg])
> >
> > We would like to know the reason behind this error.?
>
> Sounds typical of an interference between the playback and record
> programming flows, e.g. when changing a shared register. Not all I2S
> tolerate dynamic changes from RX or TX only to full-duplex.



-- 

With Best Regards,

Mohan Prasath

VVDN Technologies Pvt Ltd

Cell: +91 9629768919

Web: www.vvdntech.com

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