documentation: poky-ref-manual - method for discovering features

Fixes [YOCTO #3292]

Added a bit to the start of the Features chapter to give the user
a method they can use to discover recipes that are checking for
features added to the image.

(From yocto-docs rev: 261cc16ad900f7f5254fa97dab82beab94f717d3)

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

1 files changed, 19 insertions, 0 deletions

diff --git a/documentation/poky-ref-manual/ref-features.xml b/documentation/poky-ref-manual/ref-features.xml
index 2178d2a322..ec70547314 100644
--- a/documentation/poky-ref-manual/ref-features.xml
+++ b/documentation/poky-ref-manual/ref-features.xml
@@ -24,6 +24,25 @@
         be included if the distribution itself does not support them.
     </para>
 
+    <para>
+        One method you can use to determine which recipes are checking to see if a 
+        particular feature is contained or not is to <filename>grep</filename> through 
+        the metadata for the feature.
+        Here is an example that discovers the recipes whose build is potentially 
+        changed based on a given feature:
+        <literallayout class='monospaced'>
+     $ cd $HOME/poky
+     $ git grep 'contains.*MACHINE_FEATURES.*&lt;feature&gt;'
+        </literallayout>
+    </para>
+
+    <para>
+        This chapter provides a reference of shipped machine and distro features
+        you can include as part of the image, a reference on image types you can 
+        build, and a reference on feature backfilling.
+    </para> 
+        
+
     <section id='ref-features-distro'>
         <title>Distro</title>