Linaro Debian pre-built kernel configuration


#1

Hi,

I would like to build the same kernel that is used in Linaro Debian distribution on DragonBoard (4.14.0-qcomlt-arm64). For example, it is used in the boot-linaro-buster-dragobnboard-410c-359.img image.
Is the configuration for this kernel available anywhere?

Running make defconfig distro.config as described in instuctions produces a different kernel.

Configuration files located in/proc/config.gz and /boot/config-4.14.0-qcomlt-arm64 on the board also produce a different kernel.

I assumed that these configurations would produce the same kernel as the pre-built one. This is why I assumed there would be no need to copy the kernel modules in a previous topic:


#2

if you use the same source code, you should be able to build a ‘similar’ kernel, it won’t be the same “binary” file, but it should be the same kernel.

can you provide more information about the difference you are seeing?


#3

If the kernels are using the same configuration and have the same version number (output of uname -r), I should be able to swap them without redeploying kernel modules. However, this was not the case, for example in this topic:

Also, output of lsmod is different after flashing the kernel.

I’m building from branch release/qcomlt-4.14.


#4

For instructions on building an old kernel rather than the latest take a look at the 18.01 release notes (scroll down):
http://releases.linaro.org/96boards/dragonboard410c/linaro/debian/18.01/

(although I would never try to use old modules so I can’t promise it is sufficient to pass all the vermagic checks)


#5

well, as @danielt pointed out there can be issues with module versioning. When we build the kernel we set KERNELRELEASE variable, and if you build yourself you would need to do that too…

you can review our build script here:
https://git.linaro.org/ci/job/configs.git/tree/lt-qcom-linux/builders.sh

in the current situation you should set it as
KERNELRELEASE=4.14.0-qcomlt-arm64


#6

Thanks for the hints!

I was able to deploy the custom kernel without changes to rootfs and modules by building from the debian-qcom-dragonboard410c-18.01 tag instead of the release/qcomlt-4.14 branch.