[RFC PATCH 0/5] Apple Macs machine-level ASoC driver

[Martin Povišer]

> On 22. 4. 2022, at 14:44, Mark Brown <broonie at kernel.org> wrote:
> 
> On Fri, Apr 22, 2022 at 02:36:03PM +0200, Martin Povišer wrote:
> 
>>> Ah, I think the confusion here is that I'm using slot and channel
>>> interchangably whereas you're saying that previously the driver would
>>> allocate two channels to each speaker with duplicate data?
> 
>> I guess you could say that. Not that there’s duplicate data on the I2S
>> bus, but the speaker amp would previously be configured to look for the
>> left and right channel in the same TDM slot (see e.g. set_tdm_slot of
>> tas2770 [0]).  (Each speaker amp drives a single speaker, but it still
>> has a notion of left and right channel.)
> 
> Oh, I see - the speaker actually allows configuration of the slots
> independently.  Usually the left/right thing on mono devices only does
> something for I2S where the bus clocking enforces that there be both
> left and right channels.  Either configuration is fine by me TBH, if you
> can do that then you could just keep them mapped to the same channel
> then mark the control as disabled since it should have no effect.

Well but is there some established way to mark a control as disabled?

Another issue here is that if I disable it I can’t leave the routing
control in it’s default value, which is ‘I2C Offset’ and makes the speaker
amp ignore the slot mapping.