BUGID#_807: documentation/poky-ref-manual/ref-variables.xml: BBFILE_PRIORITY updated

BUGID#_807 - I updated the description of the BBFILE_PRIORITY variable
to provide more detail.  Input from Tom Zanussi on this fix.

(From yocto-docs rev: 7865b8f1d6298a8943e8a512c07b1a32f16679f6)

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

1 files changed, 16 insertions, 3 deletions

diff --git a/documentation/poky-ref-manual/ref-variables.xml b/documentation/poky-ref-manual/ref-variables.xml
index 2e3dbb6686..8b1470b533 100644
--- a/documentation/poky-ref-manual/ref-variables.xml
+++ b/documentation/poky-ref-manual/ref-variables.xml
@@ -87,9 +87,22 @@
 
         <glossentry id='var-BBFILE_PRIORITY'><glossterm>BBFILE_PRIORITY</glossterm>
             <glossdef>
-                <para>Assigns different priorities to recipe files in different layers. 
-                    This variable is useful in situations where the same package might appear in multiple layers.
-                    It allows you to choose what takes precedence.</para>
+                <para>Assigns different priorities to recipe files in different layers.</para>
+                <para>This variable is useful in situations where the same package appears in
+                    more than one layer. 
+                    Setting BBFILE_PRIORITY allows you to prioritize a
+                    layer against other layers that contain the same package - effectively
+                    letting you control the precedence for the multiple layers. 
+                    The precedence established through this variable stands regardless of a
+                    layer's package version (PV variable). 
+                    For example, a layer that has a package with a higher PV value but for 
+                    which the BBFILE_PRIORITY is set to have a lower precedence still has a 
+                    lower precedence.</para>
+                <para>A larger value for the BBFILE_PRIORITY variable results in a higher
+                    precedence. 
+                    For example, the value 6 has a higher precedence than the
+                    value 5. 
+                    By default, the BBFILE_PRIORITY variable is set to the value 5.</para>
             </glossdef>
         </glossentry>