From: "Martin Povišer" <povik@cutebit.org>
To: Mark Brown <broonie@kernel.org>
Cc: devicetree@vger.kernel.org, alsa-devel@alsa-project.org,
"Sven Peter" <sven@svenpeter.dev>,
linux-kernel@vger.kernel.org, "Hector Martin" <marcan@marcan.st>,
"Takashi Iwai" <tiwai@suse.com>,
"Liam Girdwood" <lgirdwood@gmail.com>,
"Rob Herring" <robh+dt@kernel.org>,
"Mark Kettenis" <kettenis@openbsd.org>,
"Martin Povišer" <povik+lin@cutebit.org>,
"Krzysztof Kozlowski" <krzk+dt@kernel.org>
Subject: Re: [RFC PATCH 3/5] HACK: ASoC: Tolerate N-cpus-to-M-codecs links
Date: Mon, 25 Apr 2022 14:34:33 +0200 [thread overview]
Message-ID: <9F8BCBA8-5EE3-4F87-9518-91CB7AB4E077@cutebit.org> (raw)
In-Reply-To: <YmaTHTKWAfM7FCcY@sirena.org.uk>
> On 25. 4. 2022, at 14:25, Mark Brown <broonie@kernel.org> wrote:
>
> On Fri, Apr 22, 2022 at 04:06:06PM +0200, Martin Povišer wrote:
>>> On 4. 4. 2022, at 14:28, Mark Brown <broonie@kernel.org> wrote:
>
>>> We need to figure out an interface for describing which CODEC/CPU
>>> combinations are connected to each other. I'm not seeing a great way to
>>> do that right now, probably some side data table is going to be needed,
>>> or perhaps the CPU DAI drivers can be persuaded to only have one DAI
>>> actually register and claim to support more channels? I'm not sure how
>>> a configuraiton like this is going to work at userspace level if the
>>> multiple CPU DAIs end up being visible...
>
>> To understand the issue better: How could the multiple CPU DAIs be
>> visible from userspace?
>
> If you register two separate DAIs (well, links) with the API without
> doing anything else the API will just expose them to userspace as two
> separate things with no indication that they're related.
Sure, but what I am addressing here is a single DAI link with multiple
CPU DAIs, invoked in DT like this:
dai-link@0 {
link-name = "Speakers";
mclk-fs = <256>;
cpu {
sound-dai = <&mca 0>, <&mca 1>;
};
codec {
sound-dai = <&speaker_left_woof1>,
<&speaker_right_woof1>,
<&speaker_left_tweet>,
<&speaker_right_tweet>,
<&speaker_left_woof2>,
<&speaker_right_woof2>;
};
};
>> What about this interim solution: In case of N-to-M links we put in
>> the most restrictive condition for checking capture/playback stream
>> validity: we check all of the CPU DAIs. Whatever ends up being the
>> proper solution later can only be less restrictive than this.
>
> That's not the issue here?
Well to me it looks like it is. Because if I invoke the DAI link like
I quoted above, and the platform driver supports it, the playback/capture
stream validity check is the only place it breaks down. Notwithstanding
this may be the wrong API as you wrote.
>> As a reminder what happens on the Macs: the platform driver drives
>> all the CPU-side I2S ports that belong to the link with the same data,
>> so the particular CPU/CODEC wiring doesn’t matter.
>
> Oh, that's not something I was aware of. In that case this is the wrong
> API - you should be using DPCM to map one front end onto multiple back
> ends (Kirkwood does something similar IIRC, there will be other examples
> but that's probably the simplest). The back ends probably don't really
> need to know that they're on the same physical bus (if indeed they are).
I guess I need to look into that.
next prev parent reply other threads:[~2022-04-25 12:35 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-03-31 0:04 [RFC PATCH 0/5] Apple Macs machine-level ASoC driver Martin Povišer
2022-03-31 0:04 ` [RFC PATCH 1/5] dt-bindings: sound: Add Apple Macs sound system Martin Povišer
2022-03-31 0:04 ` [RFC PATCH 2/5] HACK: ASoC: Add card->filter_controls hook Martin Povišer
2022-03-31 11:34 ` Mark Brown
2022-03-31 0:04 ` [RFC PATCH 3/5] HACK: ASoC: Tolerate N-cpus-to-M-codecs links Martin Povišer
2022-04-04 12:28 ` Mark Brown
2022-04-22 14:06 ` Martin Povišer
2022-04-25 12:25 ` Mark Brown
2022-04-25 12:34 ` Martin Povišer [this message]
2022-04-25 12:55 ` Mark Brown
2022-04-25 13:11 ` Martin Povišer
2022-04-25 13:46 ` Mark Brown
2022-04-25 13:55 ` Martin Povišer
2022-03-31 0:04 ` [RFC PATCH 4/5] ASoC: Introduce snd_soc_of_get_dai_link_cpus Martin Povišer
2022-03-31 0:04 ` [RFC PATCH 5/5] ASoC: Add macaudio machine driver Martin Povišer
2022-03-31 11:59 ` Mark Brown
[not found] ` <4651D426-BA1A-418F-90E5-278C705DA984@cutebit.org>
2022-03-31 12:56 ` Mark Brown
2022-03-31 12:34 ` [RFC PATCH 0/5] Apple Macs machine-level ASoC driver Mark Brown
2022-03-31 13:28 ` Hector Martin
2022-03-31 14:33 ` Mark Brown
[not found] ` <CCE4A06E-6D6F-457D-B3C5-C36209BF38D3@cutebit.org>
2022-03-31 14:18 ` Mark Brown
[not found] ` <6D199EAB-FE14-4030-96A7-2E0E89D25FAB@cutebit.org>
2022-03-31 15:36 ` Mark Brown
2022-04-22 10:43 ` Martin Povišer
2022-04-22 11:19 ` Mark Brown
2022-04-22 11:28 ` Martin Povišer
2022-04-22 11:33 ` Mark Brown
2022-04-22 11:44 ` Martin Povišer
2022-04-22 12:22 ` Mark Brown
2022-04-22 12:36 ` Martin Povišer
2022-04-22 12:44 ` Mark Brown
2022-04-22 12:53 ` Martin Povišer
2022-04-22 13:06 ` Mark Brown
2022-04-22 13:59 ` Martin Povišer
2022-04-05 9:31 ` (subset) " Mark Brown
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