[Buildroot] [.config file] Generating buildroot-like .config file from "linux-like" .config file

[Jonathan Neuschäfer]

On Tue, Jul 25, 2017 at 05:03:03PM +0200, vr roriz wrote:
> I found a possible path for this procedure. On menuconfig, under Kernel
> config, I can define a custom config file (for the Kernel). Then I can save
> this "mirroring" with a savedefconfig. I will test.
> 
> Source:
> https://stackoverflow.com/questions/1414968/how-do-i-configure-the-linux-kernel-within-buildroot
> 
> Is that the way people usually do that?

I think it usually works in the following way:

1) You create a Linux defconfig, and store it under
   arch/<architecture>/configs/<board>_defconfig, if it doesn't exist
   already.
2) You use a kernel branch or patch that contains this Linux defconfig.
3) You let BR2_LINUX_KERNEL_DEFCONFIG point to this defconfig.
4) Optionally, you create a *buildroot* defconfig that contains the
   relevant BR2_LINUX_KERNEL_DEFCONFIG line.

It's important to know which defconfig is a kernel defconfig and which
one is a buildroot defconfig.

For project specific modifications of the kernel config, there are also
some other mechanisms, like BR2_LINUX_KERNEL_CONFIG_FRAGMENT_FILES and
those listed at http://nightly.buildroot.org/manual.html#outside-br-custom.


Jonathan Neuschäfer