diff --git a/documentation/kernel-dev/kernel-dev-common.xml b/documentation/kernel-dev/kernel-dev-common.xml
index c0acac8316..618d60cbaf 100644
--- a/documentation/kernel-dev/kernel-dev-common.xml
+++ b/documentation/kernel-dev/kernel-dev-common.xml
@@ -238,6 +238,65 @@
section in the Yocto Project Development Manual.
+
+
+ Using an "In-Tree" defconfig File
+
+
+ It might be desirable to have kernel configuration fragment
+ support through a defconfig file that
+ is pulled from the kernel source tree for the configured
+ machine.
+ By default, the OpenEmbedded build system looks for
+ defconfig files in the layer used for
+ Metadata, which is "out-of-tree", and then configures them
+ using the following:
+
+ SRC_URI += "file://defconfig"
+
+ If you do not want to maintain copies of
+ defconfig files in your layer but would
+ rather allow users to use the default configuration from the
+ kernel tree and still be able to add configuration fragments
+ to the
+ SRC_URI
+ through, for example, append files, you can direct the
+ OpenEmbedded build system to use a
+ defconfig file that is "in-tree".
+
+
+
+ To specify an "in-tree" defconfig file,
+ edit the recipe that builds your kernel so that it has the
+ following command form:
+
+ KBUILD_DEFCONFIG_KMACHINE ?= defconfig_file
+
+ You need to append the variable with
+ KMACHINE and then supply the path to
+ your "in-tree" defconfig file.
+
+
+
+ Aside from modifying your kernel recipe and providing your own
+ defconfig file, you need to be sure no
+ files or statements set SRC_URI to use a
+ defconfig other than your "in-tree"
+ file (e.g. a kernel's linux-machine.inc
+ file).
+ In other words, if the build system detects a statement
+ that identifies an "out-of-tree"
+ defconfig file, that statement
+ will override your
+ KBUILD_DEFCONFIG variable.
+
+
+
+ See the
+ KBUILD_DEFCONFIG
+ variable description for more information.
+
+