modifying kernel config in Yocto

linux linux-kernel embedded-linux yocto bitbake
Michal Koziel picture Michal Koziel · Jun 24, 2015 · Viewed 19.1k times · Source

I have tried for a long time to modify the kernel config without luck. :-(

There is a BSP in meta-xxx-yyy/ with recipes-kernel/linux/linux_git.bb. I try to override the kernel config in my layer named meta-xxx-mylayer where I have recipes-kernel/linux/linux_git.bbappend and recipes-kernel/linux/files/frag.cfg

frag.cfg:

# CONFIG_NETFILTER is not set
CONFIG_AUTOFS4_FS=y

linux_git.bbappend:

COMPATIBLE_MACHINE_my_mach = "my_mach"
FILESEXTRAPATHS_prepend := "${THISDIR}/files:"
SRC_URI += "file://frag.cfg"

linux_git.bb: (just a part of the file)

KERNEL_RELEASE = "3.10"
PV = "3.10"
PR = "r10"
S = "${WORKDIR}/git"
COMPATIBLE_MACHINE = "(my_mach)"

meta-xxx-yyy/conf/machine/my_mach.conf: (there is no meta-xxx-mylayer/conf/machine/my_mach.conf)

PREFERRED_PROVIDER_virtual/kernel = "linux"
UBOOT_MACHINE = "socfpga_cyclone5_config"
KERNEL_MACHINE = "socfpga"

Build commands:

bitbake linux -c cleansstate -f
bitbake linux -c configure -f
bitbake linux -c compile -f
bitbake linux -c deploy -f

Everything builds, but when I inspect /proc/config.gz I can see that CONFIG_AUTOFS4_FS is not enabled.

I have another recipe in the meta-xxx-mylayer layer which builds and installs into rootfs just fine so I know that the layer is enabled.

The frag.cfg file is copied to ./tmp/work/my_mach-poky-linux-gnueabi/linux/3.10-r10/ during build, while the rest of the files are in ./tmp/work/my_mach-poky-linux-gnueabi/linux/3.10-r10/git/. Is that a problem?

What am I doing wrong???

Answer

Alexandre Belloni picture Alexandre Belloni · Jun 25, 2015

It is difficult to answer without seeing the real kernel recipe but what is probably happening is that the kernel recipe for the socfpga only inhertis kernel and not linux-yocto. If that is the case, then you can't change the configuration using fragments, you have to provide a full defconfig.

Related questions

How to write a simple Linux device driver?

I need to write an SPI Linux character device driver for omap4 from scratch. I know some basics of writing device drivers. But, I don't know how to start writing platform specific device driver from scratch. I've written some basic …

Read More
How to know linux scheduler time slice?

I'm looking for the value of the time slice (or quantum) of my Linux kernel. Specific Questions: Is there a /proc file which expose such an information ? (Or) Is it well-defined in the Linux header of my distributions ? (Or) Is …

Read More
insmod error: inserting './hello.ko': -1 Invalid module format"

I have just made my first driver module, the hello world module following LDD3. However unfortunately encountered this error: insmod: error inserting './hello.ko': -1 Invalid module format. I am doing this on Ubuntu 11.04, and my environment: $ uname -r 2.6.38…

Read More