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authorScott Rifenbark <srifenbark@gmail.com>2016-04-04 13:10:27 -0700
committerRichard Purdie <richard.purdie@linuxfoundation.org>2016-04-06 23:11:58 +0100
commit53bade89482d46ca30ab29330abd7490b46e532c (patch)
tree18c82cbff15b52d40fbb0488e29db1b2841e3fac /documentation/dev-manual
parent763ae4e191e09c60dd35faf569f56781515273ba (diff)
downloadopenembedded-core-contrib-53bade89482d46ca30ab29330abd7490b46e532c.tar.gz
dev-manual: Added new section describing hardware and non-hardware config
Fixes [YOCTO #5092] Added a new subsection to the "Configuring the Kernel" section to describe the part of the configuration audit phase that deals with non-hardware and hardware options. (From yocto-docs rev: 2545c3f2cf45ffcc9bf9f388d929c8242b74b011) Signed-off-by: Scott Rifenbark <srifenbark@gmail.com> Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
Diffstat (limited to 'documentation/dev-manual')
-rw-r--r--documentation/dev-manual/dev-manual-common-tasks.xml106
1 files changed, 106 insertions, 0 deletions
diff --git a/documentation/dev-manual/dev-manual-common-tasks.xml b/documentation/dev-manual/dev-manual-common-tasks.xml
index 204ef0ef0f..5e6dafd5b6 100644
--- a/documentation/dev-manual/dev-manual-common-tasks.xml
+++ b/documentation/dev-manual/dev-manual-common-tasks.xml
@@ -5133,6 +5133,112 @@
Yocto kernel.
</para>
</section>
+
+ <section id='determining-hardware-and-non-hardware-features-for-the-kernel-configuration-audit-phase'>
+ <title>Determining Hardware and Non-Hardware Features for the Kernel Configuration Audit Phase</title>
+
+ <para>
+ This section describes part of the kernel configuration audit
+ phase that most developers can ignore.
+ During this part of the audit phase, the contents of the final
+ <filename>.config</filename> file are compared against the
+ fragments specified by the system.
+ These fragments can be system fragments, distro fragments,
+ or user specified configuration elements.
+ Regardless of their origin, the OpenEmbedded build system
+ warns the user if a specific option is not included in the
+ final kernel configuration.
+ </para>
+
+ <para>
+ In order to not overwhelm the user with configuration warnings,
+ by default the system only reports on missing "hardware"
+ options because a missing hardware option could mean a boot
+ failure or that important hardware is not available.
+ </para>
+
+ <para>
+ To determine whether or not a given option is "hardware" or
+ "non-hardware", the kernel Metadata contains files that
+ classify individual or groups of options as either hardware
+ or non-hardware.
+ To better show this, consider a situation where the
+ Yocto Project kernel cache contains the following files:
+ <literallayout class='monospaced'>
+ kernel-cache/features/drm-psb/hardware.cfg
+ kernel-cache/features/kgdb/hardware.cfg
+ kernel-cache/ktypes/base/hardware.cfg
+ kernel-cache/bsp/mti-malta32/hardware.cfg
+ kernel-cache/bsp/fsl-mpc8315e-rdb/hardware.cfg
+ kernel-cache/bsp/qemu-ppc32/hardware.cfg
+ kernel-cache/bsp/qemuarma9/hardware.cfg
+ kernel-cache/bsp/mti-malta64/hardware.cfg
+ kernel-cache/bsp/arm-versatile-926ejs/hardware.cfg
+ kernel-cache/bsp/common-pc/hardware.cfg
+ kernel-cache/bsp/common-pc-64/hardware.cfg
+ kernel-cache/features/rfkill/non-hardware.cfg
+ kernel-cache/ktypes/base/non-hardware.cfg
+ kernel-cache/features/aufs/non-hardware.kcf
+ kernel-cache/features/ocf/non-hardware.kcf
+ kernel-cache/ktypes/base/non-hardware.kcf
+ kernel-cache/ktypes/base/hardware.kcf
+ kernel-cache/bsp/qemu-ppc32/hardware.kcf
+ </literallayout>
+ The following list provides explanations for the various
+ files:
+ <itemizedlist>
+ <listitem><para><filename>hardware.kcf</filename>:
+ Specifies a list of kernel Kconfig files that contain
+ hardware options only.
+ </para></listitem>
+ <listitem><para><filename>non-hardware.kcf</filename>:
+ Specifies a list of kernel Kconfig files that contain
+ non-hardware options only.
+ </para></listitem>
+ <listitem><para><filename>hardware.cfg</filename>:
+ Specifies a list of kernel
+ <filename>CONFIG_</filename> options that are hardware,
+ regardless of whether or not they are within a Kconfig
+ file specified by a hardware or non-hardware
+ Kconfig file (i.e. <filename>hardware.kcf</filename> or
+ <filename>non-hardware.kcf</filename>).
+ </para></listitem>
+ <listitem><para><filename>non-hardware.cfg</filename>:
+ Specifies a list of kernel
+ <filename>CONFIG_</filename> options that are
+ not hardware, regardless of whether or not they are
+ within a Kconfig file specified by a hardware or
+ non-hardware Kconfig file (i.e.
+ <filename>hardware.kcf</filename> or
+ <filename>non-hardware.kcf</filename>).
+ </para></listitem>
+ </itemizedlist>
+ Here is a specific example using the
+ <filename>kernel-cache/bsp/mti-malta32/hardware.cfg</filename>:
+ <literallayout class='monospaced'>
+ CONFIG_SERIAL_8250
+ CONFIG_SERIAL_8250_CONSOLE
+ CONFIG_SERIAL_8250_NR_UARTS
+ CONFIG_SERIAL_8250_PCI
+ CONFIG_SERIAL_CORE
+ CONFIG_SERIAL_CORE_CONSOLE
+ CONFIG_VGA_ARB
+ </literallayout>
+ The kernel configuration audit automatically detects these
+ files (hence the names must be exactly the ones discussed here),
+ and uses them as inputs when generating warnings about the
+ final <filename>.config</filename> file.
+ </para>
+
+ <para>
+ A user-specified kernel Metadata repository, or recipe space
+ feature, can use these same files to classify options that are
+ found within its <filename>.cfg</filename> files as hardware
+ or non-hardware, to prevent the OpenEmbedded build system from
+ producing an error or warning when an option is not in the
+ final <filename>.config</filename> file.
+ </para>
+ </section>
</section>
<section id="patching-the-kernel">