[alsa-devel] [PATCH] ASoC: imx-ssi: Fix mono playback

[Trent Piepho]

It depends on the codec connected to the I2S.  We have SSI that works
in mono mode, using a modified driver.  Our codec allows mono playback
by only using the samples on the left channel.

There is the race issue in that playback and record must both match
mono and stereo and ALSA doesn't handle substreams with constraints
that depend on other substreams in a race free manner.

On Mon, Aug 6, 2012 at 7:33 PM, Tabi Timur-B04825 <B04825 at freescale.com> wrote:
> On Mon, Aug 6, 2012 at 2:58 PM, Fabio Estevam <festevam at gmail.com> wrote:
>
>> Do you know if mono playback used to work previously in imx-ssi?
>
> I doubt it.  I don't think the I2S standard allows for mono playback,
> so the SSI would need to send the same sample twice, and I don't see
> any support for that feature in the RM.
>
> When I wrote fsl_ssi, I couldn't find any way to get mono playback to work.
>
> BTW, I can't find the original patch in my inbox or the mailing list
> archives.  When was it sent?
>
> --
> Timur Tabi
> Linux kernel developer at Freescale
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