Re: [PATCH 1/3] ASoC: Intel: avs: Unprepare a stream when recovery occurs

[Cezary Rojewski <cezary.rojewski@intel.com>]

On 10/15/2026 9:25 PM, Amadeusz Sławiński wrote:
> On Thu, 15 Oct 2026 21:02:38 +0200
> Cezary Rojewski <cezary.rojewski@intel.com> wrote:
> 
>> Recovery on alsa-lib side is handled with either:
>> 1) snd_pcm_prepare(state=XRUN)
>> 2) snd_pcm_drop/drain() -> snd_pcm_prepare(state=SETUP)
>>
>> before starting the PCM anew. Relying solely on state=XRUN leaves 2)
>> unaccounted for. sound/core/pcm_native.c ensures correctness of the
>> state machine so plain state!=PREPARED check suffices.
>>
>> This is the BE equivalent of job done previously for FE side only with
>> commit cfca1637bc2b ("ASoC: Intel: avs: Unprepare a stream when XRUN
>> occurs") and its follow up titled: ("ASoC: Intel: avs: Reset the stream
>> unless it is already prepared").
>>
>> Link: https://lore.kernel.org/linux-sound/20261010103753.16969-1-stiraspo@gmail.com/T/
>> Fixes: d070002a20fc ("ASoC: Intel: avs: HDA PCM BE operations")
>> Signed-off-by: Cezary Rojewski <cezary.rojewski@intel.com>
>> ---
>>  sound/soc/intel/avs/pcm.c | 2 ++
>>  1 file changed, 2 insertions(+)
>>
>> diff --git a/sound/soc/intel/avs/pcm.c b/sound/soc/intel/avs/pcm.c
>> index 3cf455e8b879..a0a0d645ea33 100644
>> --- a/sound/soc/intel/avs/pcm.c
>> +++ b/sound/soc/intel/avs/pcm.c
>> @@ -461,6 +461,8 @@ static int avs_dai_hda_be_prepare(struct snd_pcm_substream *substream, struct sn
>>  	link_stream = data->link_stream;
>>  	p = &be->dpcm[substream->stream].hw_params;
>>  
>> +	if (substream->runtime->state != SNDRV_PCM_STATE_PREPARED)
>> +		link_stream->link_prepared = false;
>>  	if (link_stream->link_prepared)
>>  		return 0;
>>  
> 
> It's bit late, so I can be wrong, but if you are going to execute whole
> function in most cases anyway, is link_prepared even needed? Why not just:
> 	if (substream->runtime->state == SNDRV_PCM_STATE_PREPARED)
> 		return 0;
> and remove link_prepared entirely?


I do agree that something is amiss here. As mentioned during a parallel
review [1] with these checks added, I doubt ->prepared and
->link_prepared are needed.

All of these is a separate investigation though and I've decided to go
with what has been touched, at least for now.


[1]:
https://lore.kernel.org/linux-sound/179182811090.390394.9718829794059346472.b4-ty@b4/T/#m72e50a5e55c45570926a88ebd260343e11847eaa