143 lines
6.0 KiB
XML
143 lines
6.0 KiB
XML
<!DOCTYPE chapter PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
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"http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd"
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[<!ENTITY % poky SYSTEM "../poky.ent"> %poky; ] >
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<appendix id='kernel-dev-faq'>
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<title>Kernel Development FAQ</title>
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<section id='kernel-dev-faq-section'>
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<title>Common Questions and Solutions</title>
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<para>
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The following lists some solutions for common questions.
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<qandaset>
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<qandaentry>
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<question>
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<para>
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How do I use my own Linux kernel <filename>.config</filename>
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file?
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</para>
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</question>
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<answer>
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<para>
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Refer to the "<link linkend='changing-the-configuration'>Changing the Configuration</link>"
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section for information.
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</para>
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</answer>
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</qandaentry>
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<qandaentry>
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<question>
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<para>
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How do I create configuration fragments?
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</para>
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</question>
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<answer>
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<para>
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Refer to the
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"<link linkend='creating-config-fragments'>Creating Configuration Fragments</link>"
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section for information.
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</para>
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</answer>
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</qandaentry>
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<qandaentry>
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<question>
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<para>
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How do I use my own Linux kernel sources?
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</para>
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</question>
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<answer>
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<para>
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Refer to the "<link linkend='working-with-your-own-sources'>Working With Your Own Sources</link>"
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section for information.
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</para>
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</answer>
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</qandaentry>
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<qandaentry>
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<question>
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<para>
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How do I install/not-install the kernel image on the rootfs?
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</para>
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</question>
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<answer>
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<para>
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The kernel image (e.g. <filename>vmlinuz</filename>) is provided
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by the <filename>kernel-image</filename> package.
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Image recipes depend on <filename>kernel-base</filename>.
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To specify whether or not the kernel
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image is installed in the generated root filesystem, override
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<filename>RDEPENDS_kernel-base</filename> to include or not
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include "kernel-image".</para>
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<para>See the
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"<ulink url='&YOCTO_DOCS_DEV_URL;#using-bbappend-files'>Using .bbappend Files in Your Layer</ulink>"
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section in the Yocto Project Development Tasks Manual
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for information on how to use an append file to
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override metadata.
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</para>
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</answer>
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</qandaentry>
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<qandaentry>
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<question>
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<para>
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How do I install a specific kernel module?
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</para>
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</question>
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<answer>
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<para>
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Linux kernel modules are packaged individually.
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To ensure a specific kernel module is included in an image,
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include it in the appropriate machine
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<ulink url='&YOCTO_DOCS_REF_URL;#var-RRECOMMENDS'><filename>RRECOMMENDS</filename></ulink>
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variable.</para>
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<para>These other variables are useful for installing specific
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modules:
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<literallayout class='monospaced'>
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<ulink url='&YOCTO_DOCS_REF_URL;#var-MACHINE_ESSENTIAL_EXTRA_RDEPENDS'><filename>MACHINE_ESSENTIAL_EXTRA_RDEPENDS</filename></ulink>
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<ulink url='&YOCTO_DOCS_REF_URL;#var-MACHINE_ESSENTIAL_EXTRA_RRECOMMENDS'><filename>MACHINE_ESSENTIAL_EXTRA_RRECOMMENDS</filename></ulink>
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<ulink url='&YOCTO_DOCS_REF_URL;#var-MACHINE_EXTRA_RDEPENDS'><filename>MACHINE_EXTRA_RDEPENDS</filename></ulink>
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<ulink url='&YOCTO_DOCS_REF_URL;#var-MACHINE_EXTRA_RRECOMMENDS'><filename>MACHINE_EXTRA_RRECOMMENDS</filename></ulink>
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</literallayout>
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For example, set the following in the <filename>qemux86.conf</filename>
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file to include the <filename>ab123</filename> kernel modules
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with images built for the <filename>qemux86</filename> machine:
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<literallayout class='monospaced'>
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MACHINE_EXTRA_RRECOMMENDS += "kernel-module-ab123"
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</literallayout>
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For more information, see the
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"<link linkend='incorporating-out-of-tree-modules'>Incorporating Out-of-Tree Modules</link>"
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section.
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</para>
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</answer>
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</qandaentry>
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<qandaentry>
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<question>
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<para>
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How do I change the Linux kernel command line?
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</para>
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</question>
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<answer>
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<para>
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The Linux kernel command line is typically specified in
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the machine config using the <filename>APPEND</filename> variable.
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For example, you can add some helpful debug information doing
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the following:
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<literallayout class='monospaced'>
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APPEND += "printk.time=y initcall_debug debug"
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</literallayout>
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</para>
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</answer>
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</qandaentry>
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</qandaset>
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</para>
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</section>
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</appendix>
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<!--
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vim: expandtab tw=80 ts=4
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-->
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