[bootlin/training-materials updates] master: yocto: slides: improve packagegroup overview (048501e0)

[Luca Ceresoli]

Repository : https://github.com/bootlin/training-materials
On branch  : master
Link       : https://github.com/bootlin/training-materials/commit/048501e0b0f11b3e4b9957d3628d82f44e720f15

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commit 048501e0b0f11b3e4b9957d3628d82f44e720f15
Author: Luca Ceresoli <luca.ceresoli at bootlin.com>
Date:   Fri Sep 2 12:06:17 2022 +0200

    yocto: slides: improve packagegroup overview
    
    Explain possible PACKAGE_ARCH cases more precisely. Clarify a packagegroup
    does not install any file. Mention RDEPENDS.
    
    Reword some other sentences to make room for the above changes.
    
    Signed-off-by: Luca Ceresoli <luca.ceresoli at bootlin.com>


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048501e0b0f11b3e4b9957d3628d82f44e720f15
 slides/yocto-image/yocto-image.tex | 19 +++++++++++--------
 1 file changed, 11 insertions(+), 8 deletions(-)

diff --git a/slides/yocto-image/yocto-image.tex b/slides/yocto-image/yocto-image.tex
index 4ffd3689..58c0ae52 100644
--- a/slides/yocto-image/yocto-image.tex
+++ b/slides/yocto-image/yocto-image.tex
@@ -181,17 +181,20 @@ bootloader --ptable msdos
   \begin{itemize}
     \item \code{Package groups} are a way to group packages by
       functionality or common purpose.
-    \item Package groups are used in image recipes to help building
-      the list of packages to install.
-    \item They can be found under
-      \code{meta*/recipes-core/packagegroups/}
+    \item Package groups are used to simplify image recipes.
     \item A package group is yet another recipe.
-    \item The prefix \code{packagegroup-} is always used.
+    \item They can be found under
+      \code{meta*/recipes-core/packagegroups/packagegroup-*.bb}
+    \item A package group does not install anything, but it \code{RDEPENDS}
+      on a list of packages.
     \item Be careful about the \code{PACKAGE_ARCH} value:
       \begin{itemize}
-      \item Set to the value \code{all} by default,
-      \item Must be explicitly set to \code{${MACHINE_ARCH}} when there is a machine
-        dependency.
+      \item It is set to \code{all} by default,
+      \item Must be set to \code{${TUNE_PKGARCH}} when there
+        \code{RDEPENDS:${PN}} varies based on the CPU architecture / CPU
+        tune.
+      \item Must be set to \code{${MACHINE_ARCH}} when there
+        \code{RDEPENDS:${PN}} varies based on the \code{MACHINE}.
       \end{itemize}
   \end{itemize}
 \end{frame}