[FE training-materials-updates] flash slides: improve rootfstype explanations

Michael Opdenacker michael.opdenacker at free-electrons.com
Fri Mar 28 06:32:57 CET 2014

Repository : git://git.free-electrons.com/training-materials.git

On branch  : master
Link       : http://git.free-electrons.com/training-materials/commit/?id=30003b439797069adf547fbfc652d652161508d2


commit 30003b439797069adf547fbfc652d652161508d2
Author: Michael Opdenacker <michael.opdenacker at free-electrons.com>
Date:   Fri Mar 28 05:14:28 2014 +0100

    flash slides: improve rootfstype explanations
    - They were put at a misleading place
    - Misc other improvements
    Signed-off-by: Michael Opdenacker <michael.opdenacker at free-electrons.com>


 .../sysdev-flash-filesystems.tex                   |   24 ++++++++++++++++----
 1 file changed, 19 insertions(+), 5 deletions(-)

diff --git a/slides/sysdev-flash-filesystems/sysdev-flash-filesystems.tex b/slides/sysdev-flash-filesystems/sysdev-flash-filesystems.tex
index 85e25d9..da1a458 100644
--- a/slides/sysdev-flash-filesystems/sysdev-flash-filesystems.tex
+++ b/slides/sysdev-flash-filesystems/sysdev-flash-filesystems.tex
@@ -216,9 +216,9 @@ Creating 5 MTD partitions on "omap2-nand.0":
   \item Mount the partition:\\
     \code{mount -t jffs2 /dev/mtdblock2 /mnt/flash}\\
   \item Fill the contents by writing\\
-    (copying from NFS or from external storage)
+    (copying through the network or from external storage)
   \item Other possibility: use a {\em jffs2} image (see next page to
-    produce it):\\
+    make it):\\
     \code{flash_eraseall /dev/mtd2}\\
     \code{nandwrite -p /dev/mtd2 rootfs.jffs2}
@@ -277,9 +277,6 @@ Creating 5 MTD partitions on "omap2-nand.0":
       (exact instructions depending on flash type, NOR or NAND,\\
       reuse the instructions used to flash your kernel). Make sure to
       write only the size of the image, not more!
-    \item If you boot on a jffs2 root filesystem, add
-      \code{root=/dev/mtdblock<x>} and \code{rootfstype=jffs2} to the
-      Linux command line arguments.
   \item Limitation: need to split the jffs2 image in several chunks\\
     if bigger than the RAM size.
@@ -287,6 +284,23 @@ Creating 5 MTD partitions on "omap2-nand.0":
+  \frametitle{Booting from a jffs2 root partition}
+  \begin{itemize}
+  \item To boot on a jffs2 root filesystem, add
+    \code{root=/dev/mtdblock<x>} and \code{rootfstype=jffs2} to the
+    Linux command line arguments.
+  \item The Linux kernel cannot autodetect the type of a root filesystem
+    in MTD flash. That's why the \code{rootfstype} kernel parameter is
+    needed.
+  \item For root partitions on a block device, using \code{rootfstype} 
+    (for example: \code{rootfstype=ext3}) can reduce boot time a little
+    bit. This way, the kernel doesn't have to try all the block
+    filesystems it supports.
+  \end{itemize}

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