[Buildroot] How do I configure the kernel?

[Nicholas Walton]

On Mon, Nov 23, 2009 at 12:01 PM, Grant Edwards
<grant.b.edwards at gmail.com> wrote:
> On 2009-11-23, Grant Edwards <grant.b.edwards at gmail.com> wrote:
>> On 2009-11-22, Peter Korsgaard <jacmet at uclibc.org> wrote:
>>
>>> Grant> The next question was going to be where do I put a kernel
>>> Grant> .config file if I already have one I want to use.  I can
>>> Grant> probably do a "find" to search for files named .config and
>>> Grant> figure out which is the right one. Then I assume I do "make
>>> Grant> linux26-oldconfig"?
>>>
>>> Use the LINUX26_KCONFIG environment variable, similar to
>>> BUSYBOX_CONFIG_FILE / UCLIBC_CONFIG_FILE. I'll also update the doc about
>>> that one.
>>
>> Sorry to be so dense, but I still don't get it.  I've got a
>> .config file I want to use as the starting point for a
>> "make oldconfig".  I can point LINUX26_KCONFIG at that .config
>> file, but how do I do the "make oldconfig" step?
>
> I got a working kernel by
>
>  0) pick the arch, board, target filesystem options, etc.
>  1) do a "make" and build everything (including a non-working kernel)
>  2) overwrite output/build/linux-2.6.30.2/.config with my old
>    but "working" config file.
>  3) "make ARCH=arm oldconfig" in the  output/build/linux-2.6.30.2
>    directory
>
> That doesn't feel like the proper way to do it, but it seems to
> have worked

That does work, but a more direct way would be to do the linux
configuration through buildroot.

~/buildroot % make menuconfig
~/buildroot % make linux26-menuconfig
~/buildroot % cp old-linux.config  output/build/linux-$version/.config
~/buildroot % make linux26-$either_config
~/buildroot % make

and finally

~/buildroot % make linux26-update

to copy output/build/linux-$version/.config to
target/device/$whatever/linux-$version.config, which unlike output/ is
not .gitignore'd.

Nicholas