[meta-freescale] [meta-fsl-ppc] How to change the kernel config?

[zhenhua.luo at freescale.com]

Hi Joerg, 

> -----Original Message-----
> From: meta-freescale-bounces at yoctoproject.org [mailto:meta-freescale-
> bounces at yoctoproject.org] On Behalf Of Joerg Albert
> 
> I've first tried to to use a configuration fragment (as described in the
> Yocto kernel documentation in chapter 2.2.3), but this seems to fail as
> the base recipe does not inherit linux-yocto, but kernel.
[Luo Zhenhua-B19537] The feature fragment is not used by FSL QorIQ SDK currently.  

> Putting a files/defconfig there with a line like
> 
> SRC_URI += "files://defconfig"
[Luo Zhenhua-B19537] With this way, you need to change KERNEL_DEFCONFIG in meta-fsl-ppc/conf/machine/p2041rdb.conf to point to your kernel defconfig. 

> didn't work either - I guess due to the special handling of .config via
> KERNEL_DEFCONFIG in linux-qoriq-sdk.inc in meta-fsl-ppc.
> 
> At last I tried
> 
> DELTA_KERNEL_DEFCONFIG += "${THISDIR}/files/my_incremental_config_change"
> but this searches the files in meta-fsl-ppc/recipes-kernel/linux/files
> (or inside the source code tree of the kernel), while I'd prefer to have
> it inside my custom layer.
[Luo Zhenhua-B19537] Currently kernel recipe searches the delta defconfig in ${S} and ${S}/arch/powerpc/configs/${deltacfg}".
 
> What is the easiest way to have a kernel config change (incremental
> preferred) with all files inside a custom layer?
[Luo Zhenhua-B19537] Following is my suggestion. 
	1. copy defconfig in <custom_layer>/recipe-kernel/linux/files/
	2. ensure following content is in <custom_layer>/recipe-kernel/linux/linux-qoriq-sdk_3.12.bbappend
	FILESEXTRAPATHS_prepend := "${THISDIR}/files:"
	SRC_URI += "files://defconfig"
	3. redefine KERNEL_DEFCONFIG in conf files in the custom layer, e.g, conf/local.conf
	KERNEL_DEFCONFIG = "${WORKDIR}/defconfig"


Best Regards,

Zhenhua