Q on how to save defconfig in OpenIL environment

[JohnRama]

• Environment
  LS1028ARDB

• SW

  • OpenIL
  • master branch

This would be a silly question, but I'm still struggling to get familiar with
openil environment.

Question is that once you update the config for linux for example, how do you guys usually
save the config ?

When checking the manual of build root, it describes make linux-update-defconfig. So, I've tried followings, but no success because
nxp_ls1028ardb-64b_defconfig uses fragment config files.

$make linux-menuconfig
$make linux-update-defconfig
Unable to perform linux-update-defconfig when fragment files are set
linux/linux.mk:594: recipe for target 'linux-update-defconfig' failed
make: *** [ ]linux-update-defconfig] Error 1
makoto-pc-linux :: src/openil/openil 2 » make linux-update-defconfig

I'm also interested in the method for another packages like uboot, and busybox, etc... Thanks for the help.

John

[vladimiroltean]

no success because nxp_ls1028ardb-64b_defconfig uses fragment config files.

I find this phrase confusing. Buildroot uses Kconfig, and Linux uses Kconfig. The nxp_ls1028ardb-64b_defconfig file is a defconfig for Buildroot, not for Linux. Also, it is a defconfig file, not a fragment. Buildroot does not support Kconfig fragments. So you must be talking about the BR2_LINUX_KERNEL_CONFIG_FRAGMENT_FILES variable in the Buildroot defconfig. With Buildroot it is possible to pass a list of Kconfig fragments in this variable, which are all applied after the architecture's defconfig (arch/arm64/configs/defconfig). These Kconfig fragments can be provided by the kernel repo itself (such as lsdk.config, or by the build system). These days we try to use Kconfig fragments provided by the build system less and less. This is why we have that variable set as this:

BR2_LINUX_KERNEL_CONFIG_FRAGMENT_FILES="$(LINUX_DIR)/arch/arm64/configs/lsdk.config"

This allows us to have the same configuration if we build the kernel from Buildroot or if we build it standalone.

Question is that once you update the config for linux for example, how do you guys usually save the config ?

We modify the arch/arm64/configs/lsdk.config file in the kernel repository (or arch/arm/configs/lsdk.config for LS1021A).

As to how? Either by hand (check the settings you want to enable with make menuconfig, and copy them manually to lsdk.config), or, or rare occasion, by regenerating the lsdk.config file manually.

There is an automated command for saving a defconfig with Linux (make savedefconfig), but there isn't one for saving a config fragment. So it is done (semi-manually) like this:

make defconfig
cp .config .config.defconfig
make lsdk.config
make menuconfig # apply your changes here
cp .config .config.lsdk
./scripts/diffconfig -m .config.defconfig .config.lsdk > arch/arm64/configs/lsdk.config

As to where you'd save your kernel config changes. You can either patch the linux package and modify the arch/arm64/configs/lsdk.config file, or you can modify the BR2_LINUX_KERNEL_CONFIG_FRAGMENT_FILES variable and add one more fragment, like this:

BR2_LINUX_KERNEL_CONFIG_FRAGMENT_FILES="$(LINUX_DIR)/arch/arm64/configs/lsdk.config board/nxp/ls1028ardb/linux.config"

and put your changes in there, or simply create a patch for the linux tree and git send-email --to=dev@openil.org if you think the change is relevant in a larger context and not just for you.

[JohnRama]

Thanks Vladimiroltean for the detailed explanation and making the things clear. Really appreciated. I'm fine to close this issue.

John