sphinx: import docs

The Yocto Project docs was migrated from Docbook to Sphinx in YP
 3.2. This 3.1 is an LTS release, and since 3.1 docs are 'close to'
 the docs in 3.2, we agreed to backport sphinx docs onto 3.1.

This first patch brings all changes done in 3.2 until:
7f64574f7 README: include detailed information about sphinx

There are other changes after this commit, but they will be
 selectively backported in individual patches.

This patch was generated with the following command:

git cherry-pick -n \
 $(git log --reverse --oneline \
 ac352ad7f95db7eeacb53c2778caa31800bd7c26..7f64574f7 \
| cut -f1 -d' ')

The following commits were applies in the dunfell docs, but not in
master, so they were first reverted (and squashed into this change). A
commit will reintroduce the content from these patches in the Sphinx
files in a followup patch.

069c27574 Documenation: Prepared for the 3.1.1 release
bd140f0f9 Documentation: Add 3.1.1 version updates missing from previous commit
17cc71a8f Documenation: Prepared for the 3.1.2 release
1a69e2c02 Documenation: Prepared for the 3.1.3 release
8910ac1c7 Documenation: Prepared for the 3.1.4 release

(From yocto-docs rev: c25fe058b88b893b0d146f3ed27320b47cdec236)

Signed-off-by: Nicolas Dechesne <nicolas.dechesne@linaro.org>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

1 files changed, 81 insertions, 0 deletions

diff --git a/documentation/kernel-dev/kernel-dev-faq.rst b/documentation/kernel-dev/kernel-dev-faq.rst
new file mode 100644
index 0000000000..b5e6a84eba
--- /dev/null
+++ b/documentation/kernel-dev/kernel-dev-faq.rst
@@ -0,0 +1,81 @@
+.. SPDX-License-Identifier: CC-BY-2.0-UK
+
+**********************
+Kernel Development FAQ
+**********************
+
+.. _kernel-dev-faq-section:
+
+Common Questions and Solutions
+==============================
+
+The following lists some solutions for common questions.
+
+How do I use my own Linux kernel ``.config`` file?
+--------------------------------------------------
+
+Refer to the
+":ref:`kernel-dev/kernel-dev-common:changing the configuration`"
+section for information.
+
+How do I create configuration fragments?
+----------------------------------------
+
+A: Refer to the
+":ref:`kernel-dev/kernel-dev-common:creating configuration fragments`"
+section for information.
+
+How do I use my own Linux kernel sources?
+-----------------------------------------
+
+Refer to the
+":ref:`kernel-dev/kernel-dev-common:working with your own sources`"
+section for information.
+
+How do I install/not-install the kernel image on the rootfs?
+------------------------------------------------------------
+
+The kernel image (e.g. ``vmlinuz``) is provided by the
+``kernel-image`` package. Image recipes depend on ``kernel-base``. To
+specify whether or not the kernel image is installed in the generated
+root filesystem, override ``RDEPENDS_kernel-base`` to include or not
+include "kernel-image". See the
+":ref:`dev-manual/dev-manual-common-tasks:using .bbappend files in your layer`"
+section in the
+Yocto Project Development Tasks Manual for information on how to use an
+append file to override metadata.
+
+How do I install a specific kernel module?
+------------------------------------------
+
+Linux kernel modules are packaged individually. To ensure a
+specific kernel module is included in an image, include it in the
+appropriate machine
+:term:`RRECOMMENDS` variable.
+These other variables are useful for installing specific modules:
+:term:`MACHINE_ESSENTIAL_EXTRA_RDEPENDS`
+:term:`MACHINE_ESSENTIAL_EXTRA_RRECOMMENDS`
+:term:`MACHINE_EXTRA_RDEPENDS`
+:term:`MACHINE_EXTRA_RRECOMMENDS`
+For example, set the following in the ``qemux86.conf`` file to include
+the ``ab123`` kernel modules with images built for the ``qemux86``
+machine:
+::
+
+   MACHINE_EXTRA_RRECOMMENDS += "kernel-module-ab123"
+
+For more
+information, see the "`Incorporating Out-of-Tree
+Modules <#incorporating-out-of-tree-modules>`__" section.
+
+How do I change the Linux kernel command line?
+----------------------------------------------
+
+The Linux kernel command line is
+typically specified in the machine config using the ``APPEND`` variable.
+For example, you can add some helpful debug information doing the
+following:
+::
+
+   APPEND += "printk.time=y initcall_debug debug"
+