[alsa-devel] [2.6.30-rc2][PATCH 1/2] ASoC: OMAP: Fix DSP_B format in OMAP McBSP DAI driver

Jarkko Nikula jarkko.nikula at nokia.com
Fri Apr 17 08:59:23 CEST 2009

On Thu, 16 Apr 2009 23:35:20 +0200
ext Troy Kisky <troy.kisky at boundarydevices.com> wrote:

> Arun KS wrote:
> > But when I2S is used there is no audio on Right channel(left channel
> > is working fine).
> > Thinks something is missing on tlv320aic23 driver.
> > 
> This sounds like the same problem Davinci has. From a comment in
> davinci-i2s.c
>         /* Davinci doesn't support TRUE I2S, but some codecs will have
>          * the left and right channels contiguous. This allows
>          * dsp_a mode to be used with an inverted normal frame clk.
>          * If your codec is master and does not have contiguous
>          * channels, then you will have sound on only one channel.
>          * Try using a different mode, or codec as slave.
>          *
>          * The TLV320AIC33 is an example of a codec where this works.
>          * It has a variable bit clock frequency allowing it to have
>          * valid data on every bit clock.
>          *
>          * The TLV320AIC23 is an example of a codec where this does
> not
>          * work. It has a fixed bit clock frequency with progressively
>          * more empty bit clock slots between channels as the sample
>          * rate is lowered.
>          */

Interesting codec. Arun, how is the right channel working with I2S if
you try to run with higher rate? E.g. aplay -r [48000 |
96000] /dev/urandom

The I2S mode setup in tlv320aic23_set_dai_fmt looks correct.


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