[yocto] how the &^$%^%@%^#$ does "file://defconfig" work?

[Bruce Ashfield]

On 13-04-24 08:38 AM, Robert P. J. Day wrote:
> On Wed, 24 Apr 2013, Bruce Ashfield wrote:
>
>> On 13-04-24 07:50 AM, Robert P. J. Day wrote:
>>>
>>>     been fighting with this for a couple of hours, so i'll start with
>>> the short version -- here's the current explanation for "Changing the
>>> Configuration" of your kernel:
>>>
>>> http://www.yoctoproject.org/docs/latest/kernel-dev/kernel-dev.html#changing-the-configuration
>>>
>>>     the salient bit:
>>>
>>> "If you have a complete Linux kernel .config file you want to use,
>>> copy it to a directory named files, which must be in your layer's
>>> recipes-kernel/linux directory, and name the file "defconfig"."
>>>
>>>     first, that clearly suggests that file://defconfig is to be used
>>> *only* when you have a complete .config file you want to use, which
>>> also implies that if you use that, you should not be picking up any
>>> other snippets. that's how i read that -- the use of
>>> "file://defconfig" means that that is *exactly* the final form of my
>>> eventual .config file. if that's not true, then that wording needs to
>>> change.
>>>
>>>     also, i've been trying to do just that for a couple hours now, and i
>>> am definitely *not* getting that as my final .config file used for the
>>> kernel configuration. so what should be happening here? thanks.
>>
>> What sort of delta are you seeing ? Just because something is a
>> defconfig, doesn't mean that will be exactly what you see in the final
>> .config.
>>
>> It also could vary a bit based on the kernel recipe you are using,
>> i.e. if there are configure prepends or appends, or any input
>> conditioning.
>>
>> The kernel's configuration routines will take all that input and
>> potentially select, deselect or take defaults for values that are
>> not in the defconfig .. hence why you'll see a delta.
>
>    i'm starting to follow the logic, i think it's just the wording in
> that section that needs tweaking. or maybe i just didn't get enough
> sleep ...

Or maybe both!

Bruce

>
> rday
>