Why do some config options return limited info from a search?

[valdis.kletnieks at vt.edu]

On Mon, 19 Mar 2018 00:08:10 -0000, John Whitmore said:

> Sometimes however you get a module which don't give this information. Is this
> intentional, signify something, or just an oversight for that config option?
> For example SND_HDA_CORE:

> Symbol: SND_HDA_CORE [=m]
>   Type  : tristate
>   Defined at sound/hda/Kconfig:1
>   Depends on: SOUND [=y] && !UML && SND [=y]
>   Selects: REGMAP [=y]
>   Selected by:
>     - SND_HDA_EXT_CORE [=m] && SOUND [=y] && !UML && SND [=y]
>     - SND_HDA [=m] && SOUND [=y] && !UML && SND [=y]

Some internal symbols don't have any visible menu-selects, because they are
intended to be turned on only via other things doing 'SELECT'.  After all,
SND_HDA_CORE has little to no reason to be enabled unless your kernel build
config asks for SND_HDA or SND_HDA_EXT_CORE (and *that* symbol is 'm', which is
why SND_HDA_CORE is also ''m'.  Switching EXT_CORE to 'y' will then auto-switch
this one to 'y' as well).