Re: [PATCH v3 1/2] ASoC: core: Add API to use DMI name in sound card long name

[Mengdong Lin <mengdong.lin@linux.intel.com>]

On 01/11/2017 04:03 PM, Takashi Iwai wrote:
> On Wed, 11 Jan 2017 07:32:11 +0100,
> Mengdong Lin wrote:
>>
>>
>> On 01/10/2017 03:09 PM, Takashi Iwai wrote:
>>> On Tue, 10 Jan 2017 07:42:49 +0100,
>>> mengdong.lin@linux.intel.com wrote:
>>>>
>>>> +/**
>>>> + * snd_soc_set_dmi_name() - Register DMI names to card
>>>> + * @card: The card to register DMI names
>>>> + * @flavour: The flavour "differentiator" for the card amongst its peers.
>>>> + *
>>>> + * An Intel machine driver may be used by many different devices but are
>>>> + * difficult for userspace to differentiate, since machine drivers ususally
>>>> + * use their own name as the card name (short name) and leave the card long
>>>> + * name blank. To differentiate such devices and fix bugs due to lack of
>>>> + * device-specific configurations, this function allows DMI info to be used
>>>> + * as the sound card long name, in the format of
>>>> + * "vendor.product.version.board"
>>>> + * (Character '.' are used to separate different DMI fields here).
>>>> + * This will help the userspace to load the correct UCM (Use Case Manager)
>>>> + * configuration.
>>>> + *
>>>> + * Possible card long names may be:
>>>> + * DellInc..XPS139343.01.0310JH
>>>> + * ASUSTeKCOMPUTERINC..T100TA.1.0.T100TA
>>>> + * Circuitco.MinnowboardMaxD0PLATFORM.D0.MinnowBoardMAX
>>>> + * (Please note DMI can also include '.' like"Inc." so you may see double '.
>>> '
>>>> + * sometimes)
>>>
>>> Looking at the examples above, I wonder whether the dot is the best
>>> choice as the separator.  Might other letters (e.g. ":" or "=") would
>>> be clearer?  The colon might be bad if it were combined with the
>>> alsa-lib plugin syntax, but I guess it won't happen?
>>>
>>
>> Hi Takashi,
>>
>> I found we cannot use ":" as separator. It's because we want to use
>> the card long name as the name of the directory to store UCM
>> configuration files for this card, and Autoconf cannot support ":" in
>> the directory name.
>
> OK, fair enough.
>
>> Both "=" and "-" can work, which would you suggest to use?
>> I've not observed "-" or "=" in DMI fields till now, and I guess "="
>> is less likely to be used by vendors.
>
> Yes, but OTOH, "=" would become tricky if you want to handle it in a
> shell script.

Okay. So we won't use "=".

>
> One alternative is to use "." or "-" for a separator while converting
> the existing such letters to a different one like "_".
>

It looks nice. Thanks for the tips! I'll use "-" as the separator, and 
convert the the existing "-" in DMI strings to "_".

Thanks
Mengdong