Re: [PATCH v3 11/17] ASoC: Intel: avs: Firmware resources management utilities

[Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>]

On 3/8/22 12:31, Cezary Rojewski wrote:
> On 2022-03-08 7:26 PM, Ranjani Sridharan wrote:
>> On Tue, 2022-03-08 at 19:07 +0100, Cezary Rojewski wrote:
>>>> Keeping in mind that this driver is meant for older platforms, how
>>>> likely are you to support multiple sound cards with those
>>>> topologies?
>>>
>>>
>>> Not sure what's the question here. Age of the platform has nothing to
>>> do
>>>
>>> with the subject. There is not a single DSP-capable platform that
>>> Intel
>>>
>>> has shipped that would not contain more one audio device onboard. At
>>>
>>> least I'm not aware of any.
>>
>> My question was related to your comment about multiple sound cards.
>> What I asked was do you plan to support multiple topologies with
>> modules spread across then with multiple sound component drivers with
>> the AVS driver and firmware? Does this mean you will need multiple
>> topology files and machine driver? And what is the rationale for this?
>>
>> If not, there's no need for the mutex.
> 
> Yes, avs-driver embraces granular sound card approach as opposed to 
> super card approach. There is one topology file per sound card.
> 
> That subject is not part of this patchset though.

You would still need to clarify how the same set of modules might be 
accessed or configured when different cards are created, or if there is 
a 'clean' split with a 1:1 mapping between module and cards.

The more I think of this the less practical this 'granular' approach 
looks, e.g. if you want to route the same stream to different interfaces 
handled by different cards. An example is playing a notification on 
local speakers controlled by HDaudio and a Bluetooth headset using I2S. 
This could be really fun to represent even basic volume control to 
users: controls are card-specific and some parts may be handled in 
different cards and thus different UCM files.

I really think the best split of a DSP topology is between orthogonal 
parts. When muxers/demux are used, or multi-input modules such as AEC, 
the routing complexity outweighs the benefits of a simpler card design.