[yocto] Linux Yocto style kernel errors with no config fragments

[Alex J Lennon]

Hi,

I was taking a quick look at converting the meta-raspberrypi kernel
recipes to be linux-yocto style, to provide config frag support.

I'm working with poky master, referencing linux-yocto-custom.bb in
meta-skeleton

This seems to be working as far as it goes, but I get an error when
there are no configuration fragments supplied on the SRC_URI.

| DEBUG: Executing shell function do_kernel_configme
| [INFO] doing kernel configme
| [INFO] Configuring target/machine combo: "standard/raspberrypi"
| [INFO] collecting configs in ./.meta/meta-series
| cat: .meta/cfg/standard/raspberrypi/config_frag.txt: No such file or
directory
| cat: .meta/cfg/standard/raspberrypi/config_frag.txt: No such file or
directory
| mv: cannot stat
`[.....]/tmp/work/raspberrypi-poky-linux-gnueabi/linux-raspberrypi/3.12.21+gitcb53ea88f75180cc1ba74f7f197c8e3fd4f47cfe-r0/linux-raspberrypi-standard-build/.tmp.config*':
No such file or directory
| creation of pre-processed config data failed
| config of "standard/raspberrypi" failed

When I add an empty file://dummy.cfg file to the SRC_URI then I can
build successfully.

When I add a dummy option CONFIG_DUMMY=y into that fragment file
do_kernel_configcheck correctly flags up that this is an unknown option
for the kernel so it seems to be pulled in ok.

Can anybody advise?

Thanks,

Alex