documentation/poky-ref-manual: Updates to several variables.

I did complete rewrites of RDEPENDS, RRECOMMENDS,
MACHINE_ESSENTIAL_EXTRA_RDEPENDS, MACHINE_ESSENTIAL_EXTRA_RRECOMMENDS,
MACHINE_EXTRA_RDEPENDS, and MACHINE_EXTRA_RRECOMMENDS.  These are
sent out for review but these changes represent the first attempt
to clear up confusion on how the six variables are used and relate
to each other.

(From yocto-docs rev: 1d93707fb9383d51322e96eb521e96fcac8bcc47)

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

2 files changed, 124 insertions, 11 deletions

diff --git a/documentation/poky-ref-manual/ref-variables.xml b/documentation/poky-ref-manual/ref-variables.xml
index 9089ccb..3e176f1 100644
--- a/documentation/poky-ref-manual/ref-variables.xml
+++ b/documentation/poky-ref-manual/ref-variables.xml
@@ -663,29 +663,142 @@
             </glossdef>
          </glossentry>
 
-         <glossentry id='var-MACHINE_ESSENTIAL_RDEPENDS'><glossterm>MACHINE_ESSENTIAL_RDEPENDS</glossterm>
+         <glossentry id='var-MACHINE_ESSENTIAL_EXTRA_RDEPENDS'><glossterm>MACHINE_ESSENTIAL_EXTRA_RDEPENDS</glossterm>
             <glossdef>
-                <para>Specifies the list of packages required to boot the device.</para>
+                <para>
+                    A list of packages that must be installed as part of the package being 
+                    built in order for the 
+                    resulting image to boot on the system. 
+                    The machine depends on these items - without them it will not boot.
+                    If a package in this list cannot be found during the build, the build
+                    will not complete.
+                    Some examples of these machine essentials are flash, screen, keyboard, mouse, 
+                    or touchscreen drivers (depending on the machine).
+                </para>
+                <para>
+                    For example, suppose you are building a runtime package that depends
+                    on a mouse driver.
+                    In this case, you would use the following 
+                    <filename>MACHINE_ESSENTIAL_EXTRA_RDEPENDS</filename>
+                    statement:
+                    <literallayout class='monospaced'>
+     MACHINE_ESSENTIAL_EXTRA_RDEPENDS += "&lt;mouse_driver&gt;"
+                    </literallayout>
+                </para>
             </glossdef>
          </glossentry>
 
-         <glossentry id='var-MACHINE_ESSENTIAL_RRECOMMENDS'><glossterm>MACHINE_ESSENTIAL_RRECOMMENDS</glossterm>
+         <glossentry id='var-MACHINE_ESSENTIAL_EXTRA_RRECOMMENDS'><glossterm>MACHINE_ESSENTIAL_EXTRA_RRECOMMENDS</glossterm>
             <glossdef>
-                <para>Specifies the list of packages required to boot the device (usually
-                    additional kernel modules).</para>
+                <para>
+                    A list of packages that must be installed as part of the package being 
+                    built in order for the 
+                    resulting image to boot on the system. 
+                    The machine depends on these items - without them it will not boot.
+                    If a package in this list cannot be found during the build, the build
+                    will not complete.
+                </para>
+                <para>
+                    This variable is similar to the 
+                    <link linkend='var-MACHINE_ESSENTIAL_EXTRA_RDEPENDS'>MACHINE_ESSENTIAL_EXTRA_RDEPENDS</link>
+                    with the exception that the package being built does not have a build 
+                    dependency on the variable's list of packages.
+                </para>
+                <para> 
+                    Someone help me out here... How can this list be "recommended" yet part 
+                    of the machine essential list?
+                    Seems to me that anything that is machine essential pretty much needs to 
+                    be there.
+                    The rest of this section needs an appropriate example.
+                </para>
+                <para>
+                    Some examples of these machine essentials are flash, screen, keyboard, mouse, 
+                    or touchscreen drivers (depending on the machine).
+                </para>
+                <para>
+                    For example, suppose you are building a runtime package that depends
+                    on a mouse driver.
+                    In this case, you would use the following 
+                    <filename>MACHINE_ESSENTIAL_EXTRA_RDEPENDS</filename>
+                    statement:
+                    <literallayout class='monospaced'>
+     MACHINE_ESSENTIAL_EXTRA_RDEPENDS += "&lt;mouse_driver&gt;"
+                    </literallayout>
+                </para>
             </glossdef>
         </glossentry>
 
          <glossentry id='var-MACHINE_EXTRA_RDEPENDS'><glossterm>MACHINE_EXTRA_RDEPENDS</glossterm>
             <glossdef>
-                <para>Specifies the list of packages required to use the devices</para>
+                <para>
+                    A list of packages that should be installed as part of the package  
+                    being built in order for the 
+                    resulting image to boot on the system and achieve full functionality. 
+                    Although the machine does not need these items in order to boot, if you want the 
+                    extra functionality they provide the package being built depends on them
+                    being there.  
+                    If a package in this list cannot be found during the build, the build
+                    will not complete.
+                </para>
+                <para>
+                    I need a real-world example here....
+                </para>
+                <para>
+                    An example of a machine extra is a WiFi driver.
+                    The machine may or may not have a WiFi card.
+                    If it does, the package with the driver needs to be present for the card to work.
+                    However, if the machine does not have a WiFi card, the machine will still boot.
+                </para>
+                <para>
+                    For example, suppose you are building a runtime package that depends
+                    on a WiFi driver.
+                    In this case, you would use the following 
+                    <filename>MACHINE_EXTRA_RDEPENDS</filename>
+                    statement:
+                    <literallayout class='monospaced'>
+     MACHINE_EXTRA_RDEPENDS += "&lt;wifi_driver&gt;"
+                    </literallayout>
+                </para>
             </glossdef>
          </glossentry>
 
          <glossentry id='var-MACHINE_EXTRA_RRECOMMENDS'><glossterm>MACHINE_EXTRA_RRECOMMENDS</glossterm>
             <glossdef>
-                <para>Specifies the list of packages useful to use the device (e.g.
-                    additional kernel modules)</para>
+                <para>
+                    A list of packages that should be installed as part of the package  
+                    being built in order for the 
+                    machine to boot and achieve full functionality. 
+                    Although the machine does not need these items in order to boot, if you want the 
+                    extra functionality they provide the package being built should include
+                    them.  
+                </para>
+                <para>
+                    This variable is similar to the 
+                    <link linkend='var-MACHINE_EXTRA_RDEPENDS'>MACHINE_EXTRA_RDEPENDS</link>
+                    with the exception that the package being built does not have a build 
+                    dependency on the variable's list of packages.
+                    If a package in this list cannot be found during the build, the build
+                    will still continue.
+                </para>
+                <para>
+                    I need a real-world example to use here please....
+                </para>
+                <para>
+                    An example of a machine extra is a WiFi driver.
+                    The machine may or may not have a WiFi card.
+                    If it does, the package with the driver needs to be present for the card to work.
+                    However, if the machine does not have a WiFi card, the machine will still boot.
+                </para>
+                <para>
+                    For example, suppose you are building a runtime package that depends
+                    on a WiFi driver.
+                    In this case, you would use the following 
+                    <filename>MACHINE_EXTRA_RDEPENDS</filename>
+                    statement:
+                    <literallayout class='monospaced'>
+     MACHINE_EXTRA_RDEPENDS += "&lt;wifi_driver&gt;"
+                    </literallayout>
+                </para>
             </glossdef>
          </glossentry>
 
diff --git a/documentation/poky-ref-manual/ref-varlocality.xml b/documentation/poky-ref-manual/ref-varlocality.xml
index d3d931b..0a2477c 100644
--- a/documentation/poky-ref-manual/ref-varlocality.xml
+++ b/documentation/poky-ref-manual/ref-varlocality.xml
@@ -71,10 +71,10 @@
                         </link></filename></para></listitem>
                     <listitem><para><filename><link linkend='var-MACHINE_EXTRA_RRECOMMENDS'>MACHINE_EXTRA_RRECOMMENDS
                         </link></filename></para></listitem>
-                    <listitem><para><filename><link linkend='var-MACHINE_ESSENTIAL_RDEPENDS'>MACHINE_ESSENTIAL_RDEPENDS
+                    <listitem><para><filename><link linkend='var-MACHINE_ESSENTIAL_EXTRA_RDEPENDS'>MACHINE_ESSENTIAL_EXTRA_RDEPENDS
                         </link></filename></para></listitem>
-                    <listitem><para><filename><link linkend='var-MACHINE_ESSENTIAL_RRECOMMENDS'>
-                        MACHINE_ESSENTIAL_RRECOMMENDS</link></filename></para></listitem>
+                    <listitem><para><filename><link linkend='var-MACHINE_ESSENTIAL_EXTRA_RRECOMMENDS'>
+                        MACHINE_ESSENTIAL_EXTRA_RRECOMMENDS</link></filename></para></listitem>
                 </itemizedlist>
             </para>
         </section>