[PATCH v3] ASoC: fsl_sai: Force a software reset when starting in consumer mode

[Arun Raghavan]

On Thu, 26 Jun 2025, at 7:58 AM, Fabio Estevam wrote:
> Hi Arun,
>
> On Thu, Jun 26, 2025 at 8:52 AM Arun Raghavan
> <arun at arunraghavan.net> wrote:
>>
>> From: Arun Raghavan <arun at asymptotic.io>
>>
>> On an imx8mm platform with an external clock provider, when running
>> the receiver (arecord) and triggering an xrun with xrun_injection, we
>> see a channel swap/offset. This happens sometimes when running only
>> the receiver, but occurs reliably if a transmitter (aplay) is also
>> concurrently running.
>>
>> It seems that the SAI loses track of frame sync during the trigger
>> stop -> trigger start cycle that occurs during an xrun. Doing just a
>> FIFO reset in this case does not suffice, and only a software reset
>> seems to get it back on track.
>>
>> This looks like the same h/w bug that is already handled for the
>> producer case, so we now do the reset unconditionally on config
>> disable.
>>
>> Signed-off-by: Arun Raghavan <arun at asymptotic.io> Reported-by:
>> Pieterjan Camerlynck <p.camerlynck at televic.com>
>
> What about adding a Fixes tag and Cc stable so that it gets backported
> to the stable trees?

Sure! Will send in a v4 with both of these.

The commit that added the initial fix (3e3f8bd56955 ("ASoC: fsl_sai: fix
no frame clk in master mode")) refers to an errata, but I could find
anything in a couple of imx8* errata I checked.

I was wondering if there's any public documentation of this that I can
refer (and link) to?

Cheers,
Arun