Re: [RFC PATCH v2 0/2] ASoC: tegra: ASRC ratio control updates

[Jon Hunter <jonathanh@nvidia.com>]

On 05/10/2026 09:52, Sheetal wrote:
> This RFC updates the Tegra ASRC software ratio controls so userspace
> programs the integer and fractional ratio parts through one paired ALSA
> mixer control.
> 
> This is a userspace-visible ALSA mixer control ABI change. Existing
> userspace that programs the ratio with separate controls must switch from
> the legacy commands:
> 
>   amixer -c APE cset name="ASRC1 Ratio<N> Integer Part" \
>     <integer part>
>   amixer -c APE cset name="ASRC1 Ratio<N> Fractional Part" \
>     <fractional part>
> 
> to the paired control:
> 
>   amixer -c APE cset name="ASRC1 Ratio<N>" \
>     "<integer part>,<fractional part>"
> 
> For example:
> 
>   amixer -c APE cset name="ASRC1 Ratio1" "0,715827882"
> 
> The ABI change is needed because the previous separate controls can expose
> hardware to a transient mixed ratio when one part has been updated but the
> other still contains the old value. The paired control lets the driver
> validate and program the full ratio together.
> 
> For active streams, the driver only unlocks and re-locks the stream when
> the new software ratio differs from the cached ratio by more than 20%.
> Hardware allows direct updates for smaller ratio changes, while larger
> jumps require the stream lock to be refreshed.

This still applies fine on -next and I am fine with the above ABI
change. With that, for the series ...

Acked-by: Jon Hunter <jonathanh@nvidia.com>

Thanks!
Jon

-- 
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