The warning "WARNING: [kernel]: An auto generated BSP description was used, this normally indicates a misconfiguration. Check that your machine (${MACHINE}) has an associated kernel description." should not be displayed when building a non-yocto-style kernel with a yocto-style kernel recipe. Background: We build our kustom kernel with a yocto-style kernel recipe, i.e. the recipe inherits from kernel-yocto. We set our kernelconfigs for our various boards using a defconfig file added to the SRC_URI variable and a set of .scc files added to KERNEL_FEATURES. The defconfig, .scc and .cfg files all reside in the layer alongside the recipe files. This pattern now triggers the above warning on master.
I ended up creating a toggle/flag for this, since it is less error prone. The implementation is done, and after a day of soaking, I'll send it to the list.