ref-manual: Added INITRAMFS_IMAGE_BUNDLE variable description.

Fixes [YOCTO #4072]

First draft of a new variable description for
INITRAMFS_IMAGE_BUNDLE.

(From yocto-docs rev: 4f1ac2840750fa35afa7584d28464fd539883399)

Signed-off-by: Scott Rifenbark <scott.m.rifenbark@intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

1 files changed, 34 insertions, 0 deletions

diff --git a/documentation/ref-manual/ref-variables.xml b/documentation/ref-manual/ref-variables.xml
index da6ad82901..e2c0933473 100644
--- a/documentation/ref-manual/ref-variables.xml
+++ b/documentation/ref-manual/ref-variables.xml
@@ -3034,6 +3034,40 @@ recipes-graphics/xorg-font/font-alias_1.0.3.bb:PR = "${INC_PR}.3"
             </glossdef>
         </glossentry>
 
+        <glossentry id='var-INITRAMFS_IMAGE_BUNDLE'><glossterm>INITRAMFS_IMAGE_BUNDLE</glossterm>
+            <glossdef>
+                <para>
+                    Controls whether or not the image recipe specified by
+                    <link linkend='var-INITRAMFS_IMAGE'><filename>INITRAMFS_IMAGE</filename></link>
+                    is run through an extra pass during kernel compilation
+                    in order to build a single binary that contains both the
+                    kernel image and the initial RAM disk (initramfs).
+                    The combined binary is deposited into the
+                    <filename>tmp/deploy</filename> directory, which is part
+                    of the
+                    <ulink url='&YOCTO_DOCS_DEV_URL;#build-directory'>Build Directory</ulink>.
+                </para>
+
+                <para>
+                    Setting the variable to "1" in a configuration file causes
+                    the OpenEmbedded build system to make the extra pass during
+                    kernel compilation:
+                    <literallayout class='monospaced'>
+     INITRAMFS_IMAGE_BUNDLE = "1"
+                    </literallayout>
+                    <note>
+                        You must set the
+                        <filename>INITRAMFS_IMAGE_BUNDLE</filename> variable in
+                        a configuration file.
+                        You cannot set the variable in a recipe file.
+                    </note>
+                    See the
+                    <ulink url='&YOCTO_GIT_URL;/cgit/cgit.cgi/poky/tree/meta-yocto/conf/local.conf.sample.extended'>local.conf.sample.extended</ulink>
+                    file for additional information.
+                </para>
+            </glossdef>
+        </glossentry>
+
         <glossentry id='var-INITRD'><glossterm>INITRD</glossterm>
             <glossdef>
                 <para>