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documentation/dev-manual/dev-manual-kernel-appendix.xml: Comments removed

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I removed two larges sections of old comments.

(From yocto-docs rev: df1b08b621f2b449c7575b86ec90c40f1606c43d)

Signed-off-by: Scott Rifenbark <scott.m.rifenbark@intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
This commit is contained in:
Scott Rifenbark 2012-05-30 13:26:20 -07:00 committed by Richard Purdie
parent 69536d42f1
commit 614308eef0
1 changed files with 0 additions and 344 deletions
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documentation/dev-manual/dev-manual-kernel-appendix.xml
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@ -811,352 +811,8 @@
width="2in" depth="3in" align="center" scalefit="1" />
</para>
</section>
<!-- <section id='is-vfat-supported'>
<title>Is VFAT Supported?</title>
<para>
<literallayout class='monospaced'>
I entered runqemu qemux86 and it fires upthis fires up the emulator and uses the
image and filesystem in the build area created in the previous section.
Then I copied over a pre-created and formated 5.2MB VFAT file named vfat.img.
I did this with scp vfat.img root@192.168.7.2:
The file is in the root directory.
I had to do this because the mkfs.vfat vfat.img command does not work.
mkfs is not recognized in the qemu terminal session.
when I try mount -o loop -t vfat vfat.img mnt/ I get the error
mount: can't set up loop device: No space left on device.
This error is because the loop module is not currently in the kernel image.
However, this module is available in the
build area in the tarball modules-2.6.37.6-yocto-starndard+-20-qemux86.tgz.
You can add this to the kernel image by adding the
IMAGE_INSTALL += " kernel-module-loop" statement at the top of the local.conf
file in the build area and then rebuilding the kernel using bitbake.
It should just build whatever is necessary and not go through an entire build again.
The <filename>menuconfig</filename> tool provides an interactive method with which
to set kernel configurations.
In order to use <filename>menuconfig</filename> from within the BitBake environment
you need to source an environment setup script.
This script is located in the local Yocto Project file structure and is called
<filename>oe-init-build-env</filename>.
</para>
<para>
The following command sets up the environment:
<literallayout class='monospaced'>
$ cd ~/poky
$ source oe-init-build-env
$ runqemu qemux86
Continuing with the following parameters:
KERNEL: [/home/scottrif/poky/build/tmp/deploy/images/bzImage-qemux86.bin]
ROOTFS: [/home/scottrif/poky/build/tmp/deploy/images/core-image-sato-qemux86.ext3]
FSTYPE: [ext3]
Setting up tap interface under sudo
Acquiring lockfile for tap0...
WARNING: distccd not present, no distcc support loaded.
Running qemu...
/home/scottrif/poky/build/tmp/sysroots/x86_64-linux/usr/bin/qemu
-kernel /home/scottrif/poky/build/tmp/deploy/images/bzImage-qemux86.bin
-net nic,vlan=0 -net tap,vlan=0,ifname=tap0,script=no,downscript=no
-hda /home/scottrif/poky/build/tmp/deploy/images/core-image-sato-qemux86.ext3
-show-cursor -usb -usbdevice wacom-tablet -vga vmware -enable-gl -no-reboot
-m 128 &dash;&dash;append "vga=0 root=/dev/hda rw mem=128M ip=192.168.7.2::192.168.7.1:255.255.255.0 oprofile.timer=1 "
Enabling opengl
vmsvga_value_write: guest runs Linux.
</literallayout>
</para>
</section>
<section id='prepare-to-use-menuconfig'>
<title>Prepare to use <filename>menuconfig</filename></title>
<para>
[WRITER'S NOTE: Stuff from here down are crib notes]
</para>
<para>
Once menuconfig fires up you see all kinds of categories that you can interactively
investigate.
If they have an "M" in it then the feature is "modularized".
I guess that means that means that it needs to be manually linked in when the
kernel is booted??? (Not sure).
If they have an "*" then the feature is automatically part of the kernel.]
</para>
<para>
So the tmp/work/ area was created in poky and there is a .config file in there and
a .config.old file.
The old one must have been created when I exited from menuconfig after poking around
a bit.
Nope - appears to just be created automatically.
</para>
<para>
A good practice is to first determine what configurations you have for the kernel.
You can see the results by looking in the .config file in the build/tmp/work/qemux86-poky-linux area
of the local YP files.
There is a directory named linux-yocto-2.6.37* in the directory.
In that directory is a directory named linux-qemux86-standard-build.
In that directory you will find a file named .config that is the configuration file
for the kernel that will be used when you build the kernel.
You can open that file up and examine it.
If you do a search for "VFAT" you will see that that particular configuration is not
enabled for the kernel.
This means that you cannot print a VFAT text file, or for that matter, even mount one
from the image if you were to build it at this point.
</para>
<para>
You can prove the point by actually trying it at this point.
Here are the commands:
<literallayout class='monospaced'>
$ mkdir ~/vfat-test
$ cd ~/vfat-test
$ dd if=/dev/zero of=vfat.img bs=1024 count=5000 [creates a 5MB disk image]
5+0 records in
5+0 records out
5242880 bytes (5.2 MB) copied, 0.00798912 s, 656 MB/s
$ ls -lah [lists the contents of the new image. l=long, a=all, h=human readable]
total 5.1M
drwxr-xr-x 2 srifenbark scottrif 4.0K 2011-08-01 08:18 .
drwxr-xr-x 66 srifenbark scottrif 4.0K 2011-08-01 08:14 ..
-rw-r&dash;&dash;r&dash;&dash; 1 srifenbark scottrif 5.0M 2011-08-01 08:18 vfat.img
$ mkfs.vfat vfat.img [formats the disk image]
mkfs.vfat 3.0.7 (24 Dec 2009)
$ mkdir mnt [mounts the disk image]
$ sudo su [gives you root privilege]
# mount -o loop vfat.img mnt [mounts it as a loop device]
# ls mnt [shows nothing in mnt]
# mount [lists the mounted filesystems - note/dev/loop0]
/dev/sda1 on / type ext4 (rw,errors=remount-ro)
proc on /proc type proc (rw,noexec,nosuid,nodev)
none on /sys type sysfs (rw,noexec,nosuid,nodev)
none on /sys/fs/fuse/connections type fusectl (rw)
none on /sys/kernel/debug type debugfs (rw)
none on /sys/kernel/security type securityfs (rw)
none on /dev type devtmpfs (rw,mode=0755)
none on /dev/pts type devpts (rw,noexec,nosuid,gid=5,mode=0620)
none on /dev/shm type tmpfs (rw,nosuid,nodev)
none on /var/run type tmpfs (rw,nosuid,mode=0755)
none on /var/lock type tmpfs (rw,noexec,nosuid,nodev)
none on /lib/init/rw type tmpfs (rw,nosuid,mode=0755)
binfmt_misc on /proc/sys/fs/binfmt_misc type binfmt_misc (rw,noexec,nosuid,nodev)
gvfs-fuse-daemon on /home/scottrif/.gvfs type fuse.gvfs-fuse-daemon (rw,nosuid,nodev,user=srifenbark)
/dev/loop0 on /home/scottrif/vfat-test/mnt type vfat (rw)
# echo "hello world" > mnt/hello.txt [creates a text file in the mounted VFAT system]
# ls mnt [verifies the file is there]
hello.txt
# cat mnt/hello.txt [displays the contents of the file created]
hello world
# umount mnt [unmounts the system and destroys the loop]
# exit [gets out of privileged user mode]
exit
$ lsmod [this stuff Darren did to show me ]
Module Size Used by [the status of modules in the regular linux kernel]
nls_iso8859_1 4633 0
nls_cp437 6351 0
vfat 10866 0
fat 55350 1 vfat
snd_hda_codec_atihdmi 3023 1
binfmt_misc 7960 1
snd_hda_codec_realtek 279008 1
ppdev 6375 0
snd_hda_intel 25805 2
fbcon 39270 71
tileblit 2487 1 fbcon
font 8053 1 fbcon
bitblit 5811 1 fbcon
snd_hda_codec 85759 3 snd_hda_codec_atihdmi,snd_hda_codec_realtek,snd_hda_intel
softcursor 1565 1 bitblit
snd_seq_dummy 1782 0
snd_hwdep 6924 1 snd_hda_codec
vga16fb 12757 0
snd_pcm_oss 41394 0
snd_mixer_oss 16299 1 snd_pcm_oss
snd_pcm 87946 3 snd_hda_intel,snd_hda_codec,snd_pcm_oss
vgastate 9857 1 vga16fb
snd_seq_oss 31191 0
snd_seq_midi 5829 0
snd_rawmidi 23420 1 snd_seq_midi
radeon 744506 3
snd_seq_midi_event 7267 2 snd_seq_oss,snd_seq_midi
ttm 61007 1 radeon
snd_seq 57481 6 snd_seq_dummy,snd_seq_oss,snd_seq_midi,snd_seq_midi_event
drm_kms_helper 30742 1 radeon
snd_timer 23649 2 snd_pcm,snd_seq
snd_seq_device 6888 5 snd_seq_dummy,snd_seq_oss,snd_seq_midi,snd_rawmidi,snd_seq
usb_storage 50377 0
snd 71283 16 \
snd_hda_codec_realtek,snd_hda_intel,snd_hda_codec, \
snd_hwdep,snd_pcm_oss,snd_mixer_oss,snd_pcm, \
snd_seq_oss,snd_rawmidi,snd_seq,snd_timer,snd_seq_device
soundcore 8052 1 snd
psmouse 65040 0
drm 198886 5 radeon,ttm,drm_kms_helper
i2c_algo_bit 6024 1 radeon
serio_raw 4918 0
snd_page_alloc 8500 2 snd_hda_intel,snd_pcm
dell_wmi 2177 0
dcdbas 6886 0
lp 9336 0
parport 37160 2 ppdev,lp
usbhid 41116 0
ohci1394 30260 0
hid 83888 1 usbhid
ieee1394 94771 1 ohci1394
tg3 122382 0
</literallayout>
</para>
</section>
</section> -->
</appendix>
<!--
EXTRA STUFF I MIGHT NEED BUT NOW SURE RIGHT NOW.
In the standard layer structure you have several areas that you need to examine or
modify.
For this example the layer contains four areas:
<itemizedlist>
<listitem><para><emphasis><filename>conf</filename></emphasis> - Contains the
<filename>layer.conf</filename> that identifies the location of the recipe files.
</para></listitem>
<listitem><para><emphasis><filename>images</filename></emphasis> - Contains the
image recipe file.
This recipe includes the base image you will be using and specifies other
packages the image might need.</para></listitem>
<listitem><para><emphasis><filename>recipes-bsp</filename></emphasis> - Contains
recipes specific to the hardware for which you are developing the kernel.
</para></listitem>
<listitem><para><emphasis><filename>recipes-kernel</filename></emphasis> - Contains the
"append" files that add information to the main recipe kernel.
</para></listitem>
</itemizedlist>
</para>
<para>
Let's take a look at the <filename>layer.conf</filename> in the
<filename>conf</filename> directory first.
This configuration file enables the Yocto Project build system to locate and
use the information in your new layer.
</para>
<para>
The variable <filename>BBPATH</filename> needs to include the path to your layer
as follows:
<literallayout class='monospaced'>
BBPATH := "${BBPATH}:${LAYERDIR}"
</literallayout>
And, the variable <filename>BBFILES</filename> needs to be modified to include your
recipe and append files:
<literallayout class='monospaced'>
BBFILES := "${BBFILES} ${LAYERDIR}/images/*.bb \
${LAYERDIR}/images/*.bbappend \
${LAYERDIR}/recipes-*/*/*.bb \
${LAYERDIR}/recipes-*/*/*.bbappend"
</literallayout>
Finally, you need to be sure to use your layer name in these variables at the
end of the file:
<literallayout class='monospaced'>
BBFILE_COLLECTIONS += "elc"
BBFILE_PATTERN_elc := "^${LAYERDIR}/"
BBFILE_PRIORITY_elc = "9"
</literallayout>
</para>
<para>
The <filename>images</filename> directory contains an append file that helps
further define the image.
In our example, the base image is <filename>core-image-minimal</filename>.
The image does, however, need some additional modules that we are using
for this example.
These modules support the amixer functionality.
Here is the append file:
<literallayout class='monospaced'>
require recipes-core/images/poky-image-minimal.bb
IMAGE_INSTALL += "dropbear alsa-utils-aplay alsa-utils-alsamixer"
IMAGE_INSTALL_append_qemux86 += " kernel-module-snd-ens1370 \
kernel-module-snd-rawmidi kernel-module-loop kernel-module-nls-cp437 \
kernel-module-nls-iso8859-1 qemux86-audio alsa-utils-amixer"
LICENSE = "MIT"
</literallayout>
</para>
<para>
While the focus of this example is not on the BSP, it is worth mentioning that the
<filename>recipes-bsp</filename> directory has the recipes and append files for
features that the hardware requires.
In this example, there is a script and a recipe to support the
<filename>amixer</filename> functionality in QEMU.
It is beyond the scope of this manual to go too deeply into the script.
Suffice it to say that the script tests for the presence of the mixer, sets up
default mixer values, enables the mixer, unmutes master and then
sets the volume to 100.
</para>
<para>
The recipe <filename>qemu86-audio.bb</filename> installs and runs the
<filename>amixer</filename> when the system boots.
Here is the recipe:
<literallayout class='monospaced'>
SUMMARY = "Provide a basic init script to enable audio"
DESCRIPTION = "Set the volume and unmute the Front mixer setting during boot."
SECTION = "base"
LICENSE = "MIT"
LIC_FILES_CHKSUM = "file://${POKYBASE}/LICENSE;md5=3f40d7994397109285ec7b81fdeb3b58"
PR = "r4"
inherit update-rc.d
RDEPENDS = "alsa-utils-amixer"
SRC_URI = "file://qemux86-audio"
INITSCRIPT_NAME = "qemux86-audio"
INITSCRIPT_PARAMS = "defaults 90"
do_install() {
install -d ${D}${sysconfdir} \
${D}${sysconfdir}/init.d
install -m 0755 ${WORKDIR}/qemux86-audio ${D}${sysconfdir}/init.d
cat ${WORKDIR}/${INITSCRIPT_NAME} | \
sed -e 's,/etc,${sysconfdir},g' \
-e 's,/usr/sbin,${sbindir},g' \
-e 's,/var,${localstatedir},g' \
-e 's,/usr/bin,${bindir},g' \
-e 's,/usr,${prefix},g' > ${D}${sysconfdir}/init.d/${INITSCRIPT_NAME}
chmod 755 ${D}${sysconfdir}/init.d/${INITSCRIPT_NAME}
}
</literallayout>
</para>
<para>
The last area to look at is <filename>recipes-kernel</filename>.
This area holds configuration fragments and kernel append files.
The append file must have the same name as the kernel recipe, which is
<filename>linux-yocto-2.6.37</filename> in this example.
The file can <filename>SRC_URI</filename> statements to point to configuration
fragments you might have in the layer.
The file can also contain <filename>KERNEL_FEATURES</filename> statements that specify
included kernel configurations that ship with the Yocto Project.
</para>
-->
<!--
vim: expandtab tw=80 ts=4
-->