[meta-xilinx] Board specific kernel config not applied correctly

[Andreas Galauner]

Hello everbody,
I created another meta layer for my own purposes on top of meta-xilinx
and added a board (two actually, based on microzed and zedboard) for
myself. There, I have my own kernel config which aims to change the
linux-xlnx-3.10 defconfig from meta-xilinx by specifying this file in
the MACHINE_KCONFIG variable like it's done in meta-xilinx itself with
the kc705 board for example:

> CONFIG_VIRTIO_NET=m
> CONFIG_KEYBOARD_GPIO=y
> CONFIG_NEW_LEDS=y
> CONFIG_LEDS_CLASS=y
> CONFIG_LEDS_GPIO=y
> CONFIG_LEDS_TRIGGERS=y
> CONFIG_LEDS_TRIGGER_TIMER=y
> CONFIG_LEDS_TRIGGER_ONESHOT=y
> CONFIG_LEDS_TRIGGER_HEARTBEAT=y
> CONFIG_LEDS_TRIGGER_CPU=y
> CONFIG_LEDS_TRIGGER_GPIO=y
> CONFIG_LEDS_TRIGGER_DEFAULT_ON=y
> CONFIG_LEDS_TRIGGER_TRANSIENT=y


The problem I have is, that my changes never end up in the final kernel
config, because they get overwritten by kconfig as you can see in the
logfile of the configure step here:

> DEBUG: Executing shell function do_configure
> Joining configuration file /media/andy/Data/Zedboard/openembedded/meta-copter/conf/machine/boards/copter/00000_copter_microzed.kconfig.cfg
> Joining configuration file /media/andy/Data/Zedboard/openembedded/meta-xilinx/conf/machine/boards/common/linux/zynq/defconfig_3.10.cfg
> NOTE: make oldnoconfig
>   HOSTCC  scripts/basic/fixdep
>   HOSTCC  scripts/kconfig/conf.o
>   SHIPPED scripts/kconfig/zconf.tab.c
>   SHIPPED scripts/kconfig/zconf.lex.c
>   SHIPPED scripts/kconfig/zconf.hash.c
>   HOSTCC  scripts/kconfig/zconf.tab.o
>   HOSTLD  scripts/kconfig/conf
> scripts/kconfig/conf --olddefconfig Kconfig
> .config:1039:warning: override: reassigning to symbol VIRTIO_NET
> .config:1214:warning: override: reassigning to symbol KEYBOARD_GPIO
> .config:1278:warning: override: reassigning to symbol LEGACY_PTYS
> .config:2180:warning: override: reassigning to symbol NEW_LEDS
> #
> # configuration written to .config

As you can see, I already tried to prefix the file with zeros to get it
applied first because of file ordering and so on but it all didn't help.
The kernel config ends up with all my enabled features disabled.

Any ideas why this is the case and how to fix that?

Greetings,
- Andy