Re: [PATCH RFC 2/3] ASoC: audio-graph-card2: support explicitly disabled links

[Mihalcea Laurentiu <laurentiumihalcea111@gmail.com>]

On 20.05.2025 03:38, Kuninori Morimoto wrote:
> Hi Laurentiu
>
>> so, the problem with this is the fact that (assuming you've used a DT overlay
>> for the PLUGIN) you won't be able to use the DT overlay on other boards because
>> you've also added the "Headphone0", "Codec0" route which is specific to BASE's
>> Codec0. We have multiple boards so our system would look like this:
>>
>> 	BASE0			  PLUGIN
>> 	+-----------------+
>> 	| CPU0 <-> Codec0 |     +--------+
>> 	| CPU1		  | <-> | Codec1 |
>> 	+-----------------+     +--------+
>>
>>
>> 	BASE1			  PLUGIN
>> 	+-----------------+
>> 	| CPU0 <-> Codec3 |     +--------+
>> 	| CPU1		  | <-> | Codec1 |
>> 	+-----------------+     +--------+
>>
>>
>> The plugin is the same. The only difference between BASE1 and BASE0 is the fact that CPU0
>> is connected to Codec0 on BASE0, while, on BASE1, CPU0 is connected to a different codec: Codec3.
> Ah, OK, that it the reason why you added the route on BASE side...


exactly!


>
> Hmm... I think my previous suggested idea (new flag) is reasonable, but you
> mentioned that you want to check whether it was "disabled" or not.
> So, how about to add "plugin-route" and "plugin-links" instead ?
>
> BASE
> 	my_card: card {
> 		links = <&cpu0>;
> 		routing = "Headphone0", "Codec0"; /* for CPU0-Codec0 */
> 	};
>
> PLUGIN
> 	&my_card {
> 		plugin-links = <&cpu1>, <&cpu2>
> 		plugin-routing = "Headphone1", "Codec1", /* for CPU1-Codec1 */
> 		^^^^^^		 "Headphone2", "Codec2"; /* for CPU2-Codec2 */
> 	};
>
> Audio Card2 parses "links" + "plugin-links", and
> "routing" + "plugin-routing". It is more intuitive ?


hm, I believe this _should_ work. I also think that we can just drop the whole

"ignore_route_check" flag idea since you can just use "plugin-routing" in

your DT overlay to specify the CODEC-specific routes (instead of having

them in your BASE DTS). This way, you'll avoid having routes that might

not exist in your BASE DTS.


if we go for this though I think we need to clarify the usage of the

"plugin-links" and "plugin-routing" properties. For me, these properties

only make sense if you use them in a DT overlay to add additional links/routes

introduced by the PLUGIN board. This is basically a workaround the fact

that DT overlays don't support appending to the properties of the BASE

DTS.


also, I believe we can drop the whole "explicitly disabled links" idea

since IMO, links passed via the "plugin-links" property _must_ exist.


anyhow, I will have test out this new idea on our particular scenario and see

how well it works. Thank you very much for this discussion! It was really, really

helpful!


>
>>> 	BASE			  PLUGIN
>>> 	+-----------------+			^
>>> 	| CPU0 <-> Codec0 |			| Card1
>>> 	|		  |			v
>>> 	|		  |     +--------+	^
>>> 	| CPU1		  | <-> | Codec1 |	| Card2
>>> 	| CPU2		  | <-> | Codec2 |	|
>>> 	+-----------------+     +--------+	v
>> one important thing to note here is the fact that we can only
>> have 1 sound card because all DAIs (CPU0, CPU1, CPU2) belong
>> to the same component.
> Indeed it depens on the CPU side driver style.
> I have updated my driver to allow to be multi components by checking DT.
>
> I'm not sure which one (= use plugin-xxx flag or use multi Cards) is
> more intuitive, but supporting both is not bad idea ?
>
> Thank you for your help !!
>
> Best regards
> ---
> Kuninori Morimoto