ASoC driver names

[Jaroslav Kysela]

Dne 24. 04. 20 v 18:49 Mark Brown napsal(a):
> On Fri, Apr 24, 2020 at 10:52:38AM +0200, Jaroslav Kysela wrote:
>> Dne 23. 04. 20 v 20:40 Mark Brown napsal(a):
> 
>>> My instinct is that the machine driver name is being used as a
>>> proxy for something else here and that if we need to change the ABI
>>> perhaps we need to extend it rather than trying to shoehorn things into
>>> what's there.
> 
>> My point is that this information is duplicated in the sense, that we have
>> three fields with the similar contents passed from the audio driver by the
>> ASoC drivers whose set only snd_soc_card->name from the device tree.
> 
>> For generic drivers: They can pass a generic driver name (like 'ASoC
>> Simple') for the simple card driver (soc/generic/simple-card.c).
> 
>> So my proposal is to change the driver_name to the right contents (it was
>> the initial intention for this field - changed somehow for ASoC). An
>> information about the used driver which is independent on the real
>> configuration (device tree, ACPI, component enumeration etc.). In other
>> words, the name should be more close to the source (top-level driver) code
>> name than the hardware configuration.
> 
> So if it's not really going to be used for anything particularly
> concrete then I'm having a hard time summoning the enthusiasm for a
> change.

The driver name is used as the directory name in UCM / UCM2. For DT, it means 
thousands possible directories (one per board / board + codec variant and so 
on..). The generic simple asoc card is a good example.

>  It feels more like a neatness thing than anything else and the
> postitive case just isn't jumping out at me, certainly not as a thing to
> force for everything.  New stuff, sure.  I guess I'm not bothered enough
> to block any platform that has a burning desire to convert either though
> if users start coming and complaining about kernel upgrades breaking
> things we'd have to revert.

:-( I don't propose to force one way. We can conditionally change the driver 
names using a well documented CONFIG_ option to keep compatibility with the 
older user space code. The new driver names may be selected manually in the 
kernel config.

>> I would prefer to have the sound hardware description in the long name field
>> than the whole hardware platform info here, too.
> 
> Does it also cope with the DT equivalents (and I guess there's nothing
> we can do for board file based systems)?  This stuff does get used for
> embedded systems where the plastics are often important for the
> configuration.

The author of DT config knows what hardware is described, thus this person 
should be resposible for the nice GUI sound part name.

					Jaroslav

-- 
Jaroslav Kysela <perex at perex.cz>
Linux Sound Maintainer; ALSA Project; Red Hat, Inc.