kernel fragment merge in scarthgap #kernel #scarthgap

kernel fragment merge in scarthgap #kernel #scarthgap

[Gary Huband]

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In kirkstone I am able to see the merge order for linux kernel fragments by doing

bitbake -c cleansstate virtual/kernel

bitbake -c clean virtual/kernel

bitbake --verbose linux-imx > build_linux.txt

scarthgap does not produce the merge info using this method.

Is there a way to see the kernel config fragment merge order in scarthgap?

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Re: [yocto] kernel fragment merge in scarthgap #kernel #scarthgap

[Paul Gortmaker]

[[yocto] kernel fragment merge in scarthgap #kernel #scarthgap] On 08/07/2025 (Tue 11:30) Gary Huband via lists.yoctoproject.org wrote:

> In kirkstone I am able to see the merge order for linux kernel fragments by
> doing
>  
> 
> bitbake -c cleansstate virtual/kernel 
> 
> bitbake -c clean virtual/kernel 
> 
> bitbake --verbose linux-imx > build_linux.txt 
> 
>  
> 
> scarthgap does not produce the merge info using this method.
> 
> Is there a way to see the kernel config fragment merge order in scarthgap?
> 

You don't need to capture it in a file like above.  All the fragments
and their merge order and merge logs are captured in your kernel source
directory already - has been this way for many many years/releases.

At a minimum, you have to ensure the kernel is configured:

bitbake -c configure linux-yocto  # or in your case linux-imx

If you tend to build a bunch of different arch and/or BSP, then maybe
you can never remember the path to your kernel source, even with the
help of tab completion.  If I'm lazy I will use devshell to take me
directly there:

bitbake -c devshell linux-yocto   # take me to the kernel source!

In the kernel source dir you should see something like this:

root@build:~/poky/build/tmp/work-shared/qemuppc/kernel-source# ls
arch   certs    CREDITS  Documentation  fs       init      ipc     Kconfig  lib       MAINTAINERS  mm   README  samples  security  tools  virt
block  COPYING  crypto   drivers        include  io_uring  Kbuild  kernel   LICENSES  Makefile     net  rust    scripts  sound     usr
root@build:~/poky/build/tmp/work-shared/qemuppc/kernel-source# cat .metadir 
.kernel-meta
root@build:~/poky/build/tmp/work-shared/qemuppc/kernel-source# cd .kernel-meta/
root@build:~/poky/build/tmp/work-shared/qemuppc/kernel-source/.kernel-meta# ls
bsp_definition  cfg  config.queue  configs  hardware_frags.txt  meta-series  non-hardware_frags.txt  patches  patch.v6.12.standard.queue  series  unused.patch.queue
root@build:~/poky/build/tmp/work-shared/qemuppc/kernel-source/.kernel-meta# ls cfg/
merge_config_build.log  scratch
root@build:~/poky/build/tmp/work-shared/qemuppc/kernel-source/.kernel-meta# 

I expect "merge_config_build.log" is what you are after.  It contains
stuff like this:

  Merging .kernel-meta/configs/v6.12/standard/qemuppc/features/profiling/profiling.cfg
  Merging .kernel-meta/configs/v6.12/standard/qemuppc/features/debug/debug-kernel.cfg
  Value of CONFIG_DEBUG_KERNEL is redefined by fragment .kernel-meta/configs/v6.12/standard/qemuppc/features/debug/debug-kernel.cfg:
  Previous value: CONFIG_DEBUG_KERNEL=n
  New value: CONFIG_DEBUG_KERNEL=y

Have a look around inside .kernel-meta -- everything you possibly want
to know about making the final .config in the kernel build dir is here.

Paul.
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Re: [yocto] kernel fragment merge in scarthgap #kernel #scarthgap

[Gary Huband]

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Thanks, that's what I needed.

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