kernel-dev, dev-manual: Moved Yocto Linux kernel overview

Fixes [YOCTO #11630]

I took the Yocto Linux kernel overview list of kernels out of the
dev-manual and moved them to the "Yocto Project Kernel Development
and Maintenance" section in Appendix A of the kernel-dev manual.
This is a much more logical area to introduce this type of Yocto
Linux kernel information.

(From yocto-docs rev: 0a5154cb4c23697f2b8e2341c8e1dc07362443d2)

Signed-off-by: Scott Rifenbark <srifenbark@gmail.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

1 files changed, 148 insertions, 59 deletions

diff --git a/documentation/kernel-dev/kernel-dev-concepts-appx.xml b/documentation/kernel-dev/kernel-dev-concepts-appx.xml
index 8ecd04d32c..3606301cc7 100644
--- a/documentation/kernel-dev/kernel-dev-concepts-appx.xml
+++ b/documentation/kernel-dev/kernel-dev-concepts-appx.xml
@@ -7,80 +7,169 @@
 
     <section id='kernel-big-picture'>
         <title>Yocto Project Kernel Development and Maintenance</title>
+
         <para>
-            Kernels available through the Yocto Project, like other kernels, are based off the Linux
-            kernel releases from <ulink url='http://www.kernel.org'></ulink>.
-            At the beginning of a major development cycle, the Yocto Project team
-            chooses its kernel based on factors such as release timing, the anticipated release
-            timing of final upstream <filename>kernel.org</filename> versions, and Yocto Project
+            Kernels available through the Yocto Project (Linux Yocto kernels),
+            like other kernels, are based off the Linux kernel releases from
+            <ulink url='http://www.kernel.org'></ulink>.
+            At the beginning of a major Linux kernel development cycle, the
+            Yocto Project team chooses a Linux kernel based on factors such as
+            release timing, the anticipated release timing of final upstream
+            <filename>kernel.org</filename> versions, and Yocto Project
             feature requirements.
-            Typically, the kernel chosen is in the
-            final stages of development by the community.
-            In other words, the kernel is in the release
-            candidate or "rc" phase and not yet a final release.
-            But, by being in the final stages of external development, the team knows that the
-            <filename>kernel.org</filename> final release will clearly be within the early stages of
-            the Yocto Project development window.
+            Typically, the Linux kernel chosen is in the final stages of
+            development by the Linux community.
+            In other words, the Linux kernel is in the release candidate
+            or "rc" phase and has yet to reach final release.
+            But, by being in the final stages of external development, the
+            team knows that the <filename>kernel.org</filename> final release
+            will clearly be within the early stages of the Yocto Project
+            development window.
         </para>
+
+        <para>
+            This balance allows the Yocto Project team to deliver the most
+            up-to-date Linux Yocto kernel possible, while still ensuring that
+            the team has a stable official release for the baseline Linux
+            kernel version.
+        </para>
+
         <para>
-            This balance allows the team to deliver the most up-to-date kernel
-            possible, while still ensuring that the team has a stable official release for
-            the baseline Linux kernel version.
+            As implied earlier, the ultimate source for Linux Yocto kernels
+            are released kernels from <filename>kernel.org</filename>.
+            In addition to a foundational kernel from
+            <filename>kernel.org</filename>, the available Yocto Linux kernels
+            contain a mix of important new mainline developments, non-mainline
+            developments (when there is no alternative), Board Support Package
+            (BSP) developments, and custom features.
+            These additions result in a commercially released Yocto
+            Project Linux kernel that caters to specific embedded designer
+            needs for targeted hardware.
         </para>
+
         <para>
-            The ultimate source for kernels available through the Yocto Project are released kernels
-            from <filename>kernel.org</filename>.
-            In addition to a foundational kernel from <filename>kernel.org</filename>, the
-            kernels available contain a mix of important new mainline
-            developments, non-mainline developments (when there is no alternative),
-            Board Support Package (BSP) developments,
-            and custom features.
-            These additions result in a commercially released Yocto Project Linux kernel that caters
-            to specific embedded designer needs for targeted hardware.
+            You can find a web interface to the Yocto Linux kernels in the
+            <ulink url='&YOCTO_DOCS_REF_URL;#source-repositories'>Source Repositories</ulink>
+            at
+            <ulink url='&YOCTO_GIT_URL;'></ulink>.
+            If you look at the interface, you will see to the left a
+            grouping of Git repositories titled "Yocto Linux Kernel".
+            Within this group, you will find several Linux Yocto kernels
+            developed and included with Yocto Project releases:
+            <itemizedlist>
+                <listitem><para>
+                    <emphasis><filename>linux-yocto-4.1</filename>:</emphasis>
+                    The stable Yocto Project kernel to use with the Yocto
+                    Project Release 2.0.
+                    This kernel is based on the Linux 4.1 released kernel.
+                    </para></listitem>
+                <listitem><para>
+                    <emphasis><filename>linux-yocto-4.4</filename>:</emphasis>
+                    The stable Yocto Project kernel to use with the Yocto
+                    Project Release 2.1.
+                    This kernel is based on the Linux 4.4 released kernel.
+                    </para></listitem>
+                <listitem><para>
+                    <emphasis><filename>linux-yocto-4.9</filename>:</emphasis>
+                    The stable Yocto Project kernel to use with the Yocto
+                    Project Release 2.3.
+                    This kernel is based on the Linux 4.9 released kernel.
+                    </para></listitem>
+                <listitem><para>
+                    <emphasis><filename>linux-yocto-4.10</filename>:</emphasis>
+                    The default stable Yocto Project kernel to use with the
+                    Yocto Project Release 2.3.
+                    This kernel is based on the Linux 4.10 released kernel.
+                    </para></listitem>
+                <listitem><para>
+                    <emphasis><filename>linux-yocto-dev</filename>:</emphasis>
+                    A development kernel based on the latest upstream release
+                    candidate available.
+                    </para></listitem>
+            </itemizedlist>
+            <note><title>Notes</title>
+                Long Term Support Initiative (LTSI) for Yocto Linux
+                kernels is as follows:
+                <itemizedlist>
+                    <listitem><para>
+                        For Yocto Project releases 1.7, 1.8, and 2.0,
+                        the LTSI kernel is
+                        <filename>linux-yocto-3.14</filename>.
+                        </para></listitem>
+                    <listitem><para>
+                        For Yocto Project releases 2.1, 2.2, and 2.3,
+                        the LTSI kernel is <filename>linux-yocto-4.1</filename>.
+                        </para></listitem>
+                    <listitem><para>
+                        <filename>linux-yocto-4.1</filename>,
+                        <filename>linux-yocto-4.4</filename>, and
+                        <filename>linux-yocto-4.9</filename> are all LTS
+                        kernels.
+                        </para></listitem>
+                </itemizedlist>
+            </note>
         </para>
+
         <para>
-            Once a kernel is officially released, the Yocto Project team goes into
-            their next development cycle, or upward revision (uprev) cycle, while still
-            continuing maintenance on the released kernel.
+            Once a Yocto Linux kernel is officially released, the Yocto
+            Project team goes into their next development cycle, or upward
+            revision (uprev) cycle, while still continuing maintenance on the
+            released kernel.
             It is important to note that the most sustainable and stable way
-            to include feature development upstream is through a kernel uprev process.
-            Back-porting hundreds of individual fixes and minor features from various
-            kernel versions is not sustainable and can easily compromise quality.
+            to include feature development upstream is through a kernel uprev
+            process.
+            Back-porting hundreds of individual fixes and minor features from
+            various kernel versions is not sustainable and can easily
+            compromise quality.
         </para>
+
         <para>
-            During the uprev cycle, the Yocto Project team uses an ongoing analysis of
-            kernel development, BSP support, and release timing to select the best
-            possible <filename>kernel.org</filename> version.
-            The team continually monitors community kernel
-            development to look for significant features of interest.
-            The team does consider back-porting large features if they have a significant advantage.
-            User or community demand can also trigger a back-port or creation of new
-            functionality in the Yocto Project baseline kernel during the uprev cycle.
+            During the uprev cycle, the Yocto Project team uses an ongoing
+            analysis of Linux kernel development, BSP support, and release
+            timing to select the best possible <filename>kernel.org</filename>
+            Linux kernel version on which to base subsequent Yocto Linux
+            kernel development.
+            The team continually monitors Linux community kernel development
+            to look for significant features of interest.
+            The team does consider back-porting large features if they have a
+            significant advantage.
+            User or community demand can also trigger a back-port or creation
+            of new functionality in the Yocto Project baseline kernel during
+            the uprev cycle.
         </para>
+
         <para>
-            Generally speaking, every new kernel both adds features and introduces new bugs.
-            These consequences are the basic properties of upstream kernel development and are
-            managed by the Yocto Project team's kernel strategy.
-            It is the Yocto Project team's policy to not back-port minor features to the released kernel.
-            They only consider back-porting significant technological jumps - and, that is done
-            after a complete gap analysis.
-            The reason for this policy is that back-porting any small to medium sized change
-            from an evolving kernel can easily create mismatches, incompatibilities and very
-            subtle errors.
+            Generally speaking, every new Linux kernel both adds features and
+            introduces new bugs.
+            These consequences are the basic properties of upstream
+            Linux kernel development and are managed by the Yocto Project
+            team's Linux Yocto kernel development strategy.
+            It is the Yocto Project team's policy to not back-port minor
+            features to the released Linux Yocto kernel.
+            They only consider back-porting significant technological
+            jumps &dash; and, that is done after a complete gap analysis.
+            The reason for this policy is that back-porting any small to
+            medium sized change from an evolving Linux kernel can easily
+            create mismatches, incompatibilities and very subtle errors.
         </para>
+
         <para>
-            These policies result in both a stable and a cutting
-            edge kernel that mixes forward ports of existing features and significant and critical
-            new functionality.
-            Forward porting functionality in the kernels available through the Yocto Project kernel
-            can be thought of as a "micro uprev."
-            The many “micro uprevs” produce a kernel version with a mix of
-            important new mainline, non-mainline, BSP developments and feature integrations.
-            This kernel gives insight into new features and allows focused
-            amounts of testing to be done on the kernel, which prevents
-            surprises when selecting the next major uprev.
-            The quality of these cutting edge kernels is evolving and the kernels are used in leading edge
-            feature and BSP development.
+            The policies described in this section result in both a stable
+            and a cutting edge Linux Yocto kernel that mixes forward ports of
+            existing Linux kernel features and significant and critical new
+            functionality.
+            Forward porting Linux kernel functionality into the Linux Yocto
+            kernels available through the Yocto Project can be thought of as
+            a "micro uprev."
+            The many “micro uprevs” produce a Linux Yocto kernel version with
+            a mix of important new mainline, non-mainline, BSP developments
+            and feature integrations.
+            This Yocto Linux kernel gives insight into new features and
+            allows focused amounts of testing to be done on the kernel,
+            which prevents surprises when selecting the next major uprev.
+            The quality of these cutting edge Linux Yocto kernels is evolving
+            and the kernels are used in leading edge feature and BSP
+            development.
         </para>
     </section>