From 70ae82a1612bb8c723088d248ddc254c6aa56570 Mon Sep 17 00:00:00 2001 From: Scott Rifenbark Date: Tue, 7 Feb 2012 15:47:22 -0600 Subject: documentation/kernel-manual/kernel-concepts.xml: New kernel section This section is the first attempt at a new, high-level discussion of Linux Yocto Kernel configuration. The section is supposed to introduce the concepts only and leave the "How to" stuff for other areas of the documentation. I have thrown this section out to the Yocto Projects Discussion list for feedback. It will change. (From yocto-docs rev: 8d0eabe88e50d1a16fda4b845267c4ee240ce540) Signed-off-by: Scott Rifenbark Signed-off-by: Richard Purdie --- documentation/kernel-manual/kernel-concepts.xml | 110 +++++++++++------------- 1 file changed, 49 insertions(+), 61 deletions(-) (limited to 'documentation/kernel-manual') diff --git a/documentation/kernel-manual/kernel-concepts.xml b/documentation/kernel-manual/kernel-concepts.xml index 9a599f2a8c..27b32098ec 100644 --- a/documentation/kernel-manual/kernel-concepts.xml +++ b/documentation/kernel-manual/kernel-concepts.xml @@ -306,75 +306,63 @@
Kernel Configuration - Kernel configuration, along with kernel features, defines how a kernel image is - built. + Kernel configuration, along with kernel features, defines how a Linux Yocto + kernel image is built. Through configuration settings, you can customize a Linux Yocto kernel to be specific to particular hardware. For example, you can specify sound support or networking support. This section describes basic concepts behind Kernel configuration within the - Yocto Project. + Yocto Project and references you to other areas for specific configuration + applications. - WRITER NOTES: - - - - A package consists of tasks and BitBake, in most cases, behaves by fetching, unpacking, - patching, configuring, compiling, installing, packaging, writing, and building. - Configuration is part of the standard BitBake process. - - - Explain how .config is used when the kernel image is built. - Describe the role of menuconfig regarding the - .config. - Locate the .config for the user. - Not recommended to edit the .config file directly. - You can use BitBake to build and invoke the menuconfig - tool. - - - - Introduce the configuration fragment. - Step through the life of a configuration fragment from idea or need to - change something in the kernel to how it is used when the kernel image is built. - Describe how configuration fragments are created and where they live. - Make sure the syntax of configuration fragments is understood. - - - - Talk in general how the user creates a configuration fragment. - Point to example B.2 of the YP Development Manual as a way to use - menuconfig. - - - - The tool menuconfig allows you to choose the features of the - Linux Yocto kernel that will be compiled. - This tool is a convenient method to alter the .config file. - You can use a simple interface to scroll through kernel features and disable - and enable configruation variables. - When you save your changes, the contents of the .config - are altered. - You can get general information on menuconfig at - . - - - - The Yocto Project employs menuconfig by invoking it through - BitBake as follows after making sure the environment setup script has been sourced: - + Conceptually, Linux Yocto kernel configuration occurs similarly to that needed for any + Linux kernel. + The Linux Yocto kernel build process uses a .config, which + is created through the Linux Kernel Coinfiguration (LKC) tool. + You can directly set various configurations in the + .config file by using the menuconfig + tool as built by BitBake. + You can also affect the configurations in the file by using configuration fragments. + + It is not recommended that you edit the .config file directly. + + Here is are some brief descriptions of the ways you can affect the + .config file: + + The menuconfig Tool: + One of many front-ends that allows you to define kernel configurations. + Some others are make config, + make nconfig, and make gconfig. + In the Yocto Project environment, you must use BitBake to build the + menuconfig tool before you can use it to define + configurations: + $ bitbake linux-yocto -c menuconfig - - You can see how menuconfig is used to change a simple - kernel configuration in the - "Changing the  CONFIG_SMP - Configuration Using  menuconfig" section of - The Yocto Project Development Manual. - - - - END WRITER NOTES + + After the tool is built, you can interact with it normally. + You can see how menuconfig is used to change a simple + kernel configuration in the + "Changing the  CONFIG_SMP Configuration Using  menuconfig" + section of The Yocto Project Development Manual. + For general information on menuconfig, see + . + + Configuration Fragments: A file with a + list of kernel options just as they would appear syntactically in the + .config file. + Configuration fragments are typically logical groupings and are assembled + by the Yocto Project build system to produce input used by the LKC + that ultimately generates the .config file. + The + KERNEL_FEATURES + variable can be used to list configuration fragments. + For further discussion on applying configuration fragments, see the + "Linux Kernel Configuration" + section in the Yocto Project Board Support Package (BSP) Guide. + +
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