From: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
To: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>,
Mark Brown <broonie@kernel.org>
Cc: Linux-ALSA <alsa-devel@alsa-project.org>
Subject: Re: [alsa-devel] Question about DPCM FE vs BE
Date: Wed, 9 Oct 2019 09:20:42 -0500 [thread overview]
Message-ID: <2a28be44-91ad-c140-062b-4d14982042e9@linux.intel.com> (raw)
In-Reply-To: <87r23mgxl7.wl-kuninori.morimoto.gx@renesas.com>
On 10/9/19 2:57 AM, Kuninori Morimoto wrote:
>
> Hi ALSA ML
>
> In my understanding, DPCM needs FE and BE.
> And, one FE can have multiple BE, and one BE can have multiple FE.
>
> My question this time is that one snd_soc_pcm_runtime can be both
> FE and BE in the same time (= Sometimes FE, sometimes BE) ??
>
> In my understanding, it never happen.
> But, is this correct ?
It is my understanding that the current code would not support a case
where a FE is also a BE.
That said, do we want to preclude it? at some point we probably want to
get rid of the FE/BE distinction and have 'domains' that can be chained.
So it may not be a good thing to cast a restriction in stone. If at some
point we need a list of upstream/downstream clients maybe we should keep
this.
>
> I'm asking because do we need .be_clients/.fe_clients ?
> If one pcm_runtime can't be FE / BE in the same time,
> just .clients is enough I think.
>
> static int dpcm_be_connect(...)
> {
> ...
> - list_add(&dpcm->list_be, &fe->dpcm[stream].be_clients);
> - list_add(&dpcm->list_fe, &be->dpcm[stream].fe_clients);
> + list_add(&dpcm->list_be, &fe->dpcm[stream].clients);
> + list_add(&dpcm->list_fe, &be->dpcm[stream].clients);
> ...
> }
>
>
> Thank you for your help !!
> Best regards
> ---
> Kuninori Morimoto
> _______________________________________________
> Alsa-devel mailing list
> Alsa-devel@alsa-project.org
> https://mailman.alsa-project.org/mailman/listinfo/alsa-devel
>
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next prev parent reply other threads:[~2019-10-09 15:40 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-10-09 7:57 [alsa-devel] Question about DPCM FE vs BE Kuninori Morimoto
2019-10-09 14:20 ` Pierre-Louis Bossart [this message]
2019-10-09 23:50 ` Kuninori Morimoto
2019-10-10 2:20 ` Pierre-Louis Bossart
2019-10-10 2:38 ` Kuninori Morimoto
2019-10-10 14:07 ` Mark Brown
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