Setting KConfig variables in CMakeLists.txt not working with sysbuild

[Konstantin Klitenik]

Prior to moving to sysbuild, we were dynamically settings a CONFIG_ variable in our `CMakeLists.txt` based on the board passed to west. And this was working fine.

if(BOARD MATCHES "^ourboard")

  set(CONFIG_MEMFAULT_NCS_HW_VERSION "\"A9.1\"" CACHE INTERNAL "")

elseif(BOARD MATCHES "^nrf9151dk")

  set(CONFIG_MEMFAULT_NCS_HW_VERSION "\"nRF9151DK\"" CACHE INTERNAL "")

else()

  message(FATAL_ERROR "No hardware BOARD has been set for this build.")

endif()

 

After upgrading to nRFSDK 2.9.0 and using sysbuild, this no longer works. In fact, `BOARD` variable isn't even available in `CMakeLists.txt`. I tried replacing that part with `if (1)` but the new values never make it into the `.config` file (although I can see them in the CMakeCache.txt).

One way I found to make this work is to put this into `sysbuild.cmake` but this feels wrong because `CONFIG_MEMFAULT_NCS_HW_VERSION` is only needed in the app image and doesn't need to be available to mcuboot. 

What's the proper way to handle this? Am I missing something?

Thanks,

Konstantin

[Amanda Hsieh]

Hi, 

Sysbuild includes support for File Suffixes in applications, and it can also use Sysbuild file suffix support. I would suggest you use the File suffix. 

Regards,
Amanda H.

[Konstantin Klitenik]

Could you provide an example of how it would be used in my case? Based on the docs, file suffixes apply to conf/overlay files, which are not dynamic. I'm looking to dynamically set configs in CMake files. I may not be fully understanding how sysbuild works.

[Amanda Hsieh]

Then, I think you can use Kconfig as this example. 

[Konstantin Klitenik]

That's not it. You can't do pattern matching in Kconfig file.

[Amanda Hsieh]

You could consider an alternative way by using board ID as that example.