Re: [ANNOUNCE] GSoC project: Improving kconfig using a SAT solver

[Felipe Contreras]

On Wed, May 19, 2010 at 9:31 PM, Vegard Nossum <vegard.nossum@xxxxxxxxx> wrote:
> On 19 May 2010 13:05, Felipe Contreras <felipe.contreras@xxxxxxxxx> wrote:
>> Does this means that if you have a pristine kernel, and you do 'make
>> menuconfig' and don't change anything, the .config file will be empty?
>> And then, anything that you change will be in the .config file?
>
> Yes and no -- I think the plan is to retain the .config file as it is
> (i.e. it specifies more or less every option completely), so that it
> remains backwards compatible; bisection, for example, is very
> important. But yes, I think there will be a new file, say, .satconfig,
> which contains only the specific choices of the user. And this one
> would be empty, as you say, with a pristine kernel.
>
> I think, then, that the .config file will be regenerated from the
> .satconfig one each time .satconfig changes.

I see. As long as people can use .satconfig only if they want, I think
that's great.

>> On another case I do 'make ARCH=arm omap3_beagle_defconfig' then my
>> .config file will point to that particular defconfig, and I can add
>> only the changes that I want. Also, omap3_beagle_defconfig probably
>> points omap3_defconfig and only makes certain changes.
>>
>> If so, that would be awesome :)
>
> Do you mean essentially a sort of cascade of configurations that
> inherit options from a different file? That shouldn't be very hard to
> do -- I'll make a note of it for when I get that far! That has the
> potential to make the defconfig files a bit shorter and more
> manageable (not sure how big a problem that is in practice today,
> though).

Exactly. Well, I don't know if anybody considers that a problem, but
just check arch/arm/configs/*. All of them are much bigger than
needed, and some have not been updated in a long time (even as old as
2.6.11). So if you do make ARCH=arm assabet_defconfig and do a 'diff
.config assabet_defconfig' they would be completely different. This
way it's hard to keep track of the general config changes, and ARM
related changes, and OMAP3 changes, and compare with board-specific
ones.

Cheers.

-- 
Felipe Contreras
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