[question] KBUILD_OUTPUT and modules install (with INSTALL_MOD_PATH)

[Frank Wunderlich]

Hi,

i try to use modules_install target after building kernel with KBUILD_OUTPUT set

KBUILD_OUTPUT: /media/data_nvme/git/kernel/build #kernel source is in /media/data_nvme/git/kernel/BPI-R2-4.14

kernel is build successfully, but i fail on running the make modules_install target

  ERROR: Kernel configuration is invalid.
         include/generated/autoconf.h or include/config/auto.conf are missing.
         Run 'make oldconfig && make prepare' on kernel src to fix it.

Makefile:648: include/config/auto.conf: No such file or directory
make: *** [Makefile:719: include/config/auto.conf] Error 1

it looks it is ignoring the KBUILD_OUTPUT variable, as both files are present

$ ls /media/data_nvme/git/kernel/build/include/config/auto.conf
/media/data_nvme/git/kernel/build/include/config/auto.conf
$ ls /media/data_nvme/git/kernel/build/include/generated/autoconf.h
/media/data_nvme/git/kernel/build/include/generated/autoconf.h

i also tried adding KERNEL_DIR var, but also without success

sudo make ARCH=$ARCH KERNEL_DIR=$KBUILD_OUTPUT INSTALL_MOD_PATH=/media/$USER/BPI-ROOT/ modules_install

$KBUILD_OUTPUT is definitely set to right directory (checked on beginning of my function)

this message seems to be triggered by Makefile in root (here i tried to add the KBUILD_OUTPUT in the test before include without success)

 718 include/config/auto.conf:
 719     $(Q)test -e include/generated/autoconf.h -a -e $@ || (      \
 720     echo >&2;                           \
 721     echo >&2 "  ERROR: Kernel configuration is invalid.";       \
 722     echo >&2 "         include/generated/autoconf.h or $@ are missing.";\

any idea?

regards Frank