Re: kbuild question

[Kumar Gala <galak@kernel.crashing.org>]

On Feb 16, 2007, at 4:23 AM, Roman Zippel wrote:

> Hi,
>
> On Thu, 15 Feb 2007, Kumar Gala wrote:
>
>> I was wondering if there was some way to make a Kconfig menu  
>> either be just a
>> menu or a choice depending on another bool being set or not.
>>
>> What I'm trying to accomplish is if CONFIG_ONLY_HAVE_ONE is set I  
>> want it so
>> you can only select on option, however if CONFIG_ONLY_HAVE_ONE is  
>> not set you
>> should be able to select multiple options.
>
> Could you please be more specific about the problem you're trying to
> solve, instead of how you're trying to solve it?
> A real example would help a lot to understand the actual problem.

Sure, on powerpc for some of the embedded sub-architectures you can  
only select a single board to build for.  For a lot of people this is  
sufficient, however we are moving towards a world where you can  
easily build in support for multiple boards into a single kernel.

I'd like to have it such that if I'm only building support for one  
board (CONFIG_ONLY_HAVE_ONE, not going to call it that, but for this  
discussion its sufficient), you get a choice menu from Kconfig  
enforcing the ability to only select one board.  However if ! 
CONFIG_ONLY_HAVE_ONE than you can select multiple boards to build  
into your kernel.

if CONFIG_ONLY_HAVE_ONE is set we can optimize out the runtime checks  
that get added for handling the multiple board case.

Hopefully that's clear.

- k