reproduce (this is a W=1 build):
        git remote add lee-backlight https://git.kernel.org/pub/scm/linux/kernel/git/lee/backlight.git
        git fetch lee-backlight for-backlight-next
        git checkout lee-backlight/for-backlight-next
        b4 shazam https://lore.kernel.org/r/20250306140947.580324-7-tzimmermann@suse.de
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        make W=1 O=build_dir ARCH=i386 olddefconfig
        make W=1 O=build_dir ARCH=i386 SHELL=/bin/bash