[Buildroot] Kconfig - how to implement hierarchical (un-)select trees?

[Buildroot] Kconfig - how to implement hierarchical (un-)select trees?

[Alexander Kriegisch]

I read the very concise, but nonetheless puzzling kconfig-language.txt
to understand how to optimise the awfully mis-structured menuconfig of a
project I am participating in. I experimented with an own set of minimal
Config.in files, but still do not understand the ins and outs of this tool.

Does anybody know of a tutorial (incl. samples!) for kconfig? What I
want to achieve is something like this:


Main menu
=========
[ ] global setting a
[x] global setting b
...
packages -->


Packages menu
=============
[ ] package a
[ ] package b
...
[ ] package n
    kernel modules -->
    shared libs -->
    [ ] sub-package n1
...


Kernel modules
==============
[ ] kernel module a
[ ] kernel module b
...
[ ] kernel module n


Shared libs
===========
[ ] shared lib a
[ ] shared lib b
...
[ ] shared lib n


My goals & problems:

  - If package n is unselected, I want everything below it (sub-package,
    shared libs, kernel modules) unselected, too. this is the most
    important point.

  - Some kernel modules (or shared libs, respectively) in the same
    hierarchy may be interdependent. I want to auto-(un)select dependent
    modules. I got part of this working with "select", but unselecting
    works strangely. I cannot describe it any better. Somebody knowing
    the kconfig language and its tricks and tweaks may know what I mean.

  - It is necessary to auto-(un)select several shared libs if related
    kernel modules are (un)selected.

  - Sub-package n1 from the example above automatically selects a number
    of kernel modules and shared libs. They don't get unselected cleanly
    if I define additional interdependencies between elements on the
    same hierarchy level.

  - Muli-level hierarchies as such seem to be problematic anyway.

I know I would express most of the dependencies in a common programming
language such as Java, but the kconfig "language" somehow defies my
thorough understanding.

Regards
-- 
Alexander Kriegisch

[Buildroot] Kconfig - how to implement hierarchical (un-)select trees?

[Alexander Kriegisch]

I wrote earlier tonight:
>   - If package n is unselected, I want everything below it (sub-package,
>     shared libs, kernel modules) unselected, too. this is the most
>     important point.

I think I got this one working now. What disturbed my efforts were
double definitions of config variables in other Config.in includes at
unexpected places. (Did I mention the whole thing was a mess?) Sorry for
asking at all.

>   - Some kernel modules (or shared libs, respectively) in the same
>     hierarchy may be interdependent. I want to auto-(un)select dependent
>     modules. I got part of this working with "select", but unselecting
>     works strangely. I cannot describe it any better. Somebody knowing
>     the kconfig language and its tricks and tweaks may know what I mean.

Still problematic.

>   - It is necessary to auto-(un)select several shared libs if related
>     kernel modules are (un)selected.

Haven't got there yet.

>   - Sub-package n1 from the example above automatically selects a number
>     of kernel modules and shared libs. They don't get unselected cleanly
>     if I define additional interdependencies between elements on the
>     same hierarchy level.

More precisely, they do not get unselected at all, interdependency or
not. I cannot use "requires" (=depends [on]), though, because they might
be needed by other modules as well. Not sure how to resolves this, but
at least now I can unselect all libs or all kernel modules and start
over selecting packages which in turn select modules/libs they need.

>   - Muli-level hierarchies as such seem to be problematic anyway.

Resolved.