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

[Takashi Iwai]

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 at 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.

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


thanks,

Takashi