[alsa-devel] [PATCH] ASoC: codecs-ac97: Remove rate constraints

[Fabio Estevam]

Hi Maciej,

On Fri, May 8, 2015 at 8:14 PM, Maciej S. Szmigiero
<mail at maciej.szmigiero.name> wrote:

> I currently have audio running on this board at kernel based on
> vanilla 3.19 and porting required changes part-by-part to linux-next.
>
> Changes required on vanilla 3.19 to have it working are:
> * AC'97 audio support needs to be added to fsl-asoc-card,
>
> * AC'97 CODEC platform device needs to be instantiated in fsl_ssi,
>
> * IPG clock needs to be enabled in fsl_ssi AC'97 mode,
> so AC'97 regs can be accessed,
>
> * Few small fixes for AC'97 mode in fsl_ssi (missing switch label
> for format, missing  fsl_ssi_dai_probe entry in fsl_ssi_ac97_dai,
> etc.).
>
> There also is a problem with this CODEC that it seems to pull samples
> for S/PDIF output from time to time even if S/PDIF output is disabled.
>
> By default this requests samples in AC'97 slots 10/11 via SLOTREQ,
> which in turn causes SSI to enable these slots in SACCST register
> and start sending half of the sound samples there.
>
> The end result is that audio suddenly starts to play two times
> too fast.
>
> Currently, I have a workaround of setting S/PDIF slot assignment
> in CODEC to first front pair so at least it doesn't affect
> playback rate.
>
> If you like to have these changes or DT file diff then naturally
> I can share them, just they aren't production-quality as of now.

Good job!

Please keep me on Cc when you submit further ac97 patches / udoo dts,
so that I can help testing them.

Thanks,

Fabio Estevam