Documentation/gpu: Reference articles on Linux graphics stack

Add two articles on LWN about the Linux graphics stack to DRM's
list of external references. The articles document the graphics
output as a whole, including the kernel side.

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Simon Ser <contact@emersion.fr>
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240115113908.25897-1-tzimmermann@suse.de

drm/doc: Add sections about tiny drivers and external refs to intro page

Learning about the DRM subsystem could be quite overwhelming for newcomers
but there are lots of useful talks, slides and articles available that can
help to understand the needed concepts and ease the learning curve.

There are also simple DRM drivers that can be used as example about how a
DRM driver should look like.

Add sections to the introduction page, that contains references to these.

Suggested-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Javier Martinez Canillas <javierm@redhat.com>
Acked-by: Pekka Paalanen <pekka.paalanen@collabora.com>
Acked-by: Thomas Zimmermann <tzimmermann@suse.de>
Link: https://patchwork.freedesktop.org/patch/msgid/20220420072411.15104-1-javierm@redhat.com

drm/doc: Document kapi doc expectations

We've had this already for anything new. With my drm_prime.c cleanup I
also think documentation for everything already existing is complete,
and we can bake this in as a requirements subsystem wide.

v2: Improve wording a bit (Laurent), fix typo in commit message (Sam).

Acked-by: Emil Velikov <emil.velikov@collabora.com>
Acked-by: Sean Paul <sean@poorly.run>
Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Acked-by: Maxime Ripard <maxime.ripard@bootlin.com>
Acked-by: Sam Ravnborg <sam@ravnborg.org>
Acked-by: Jani Nikula <jani.nikula@intel.com>
Acked-by: Alex Deucher <alexdeucher@gmail.com>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: David Airlie <airlied@linux.ie>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Maxime Ripard <maxime.ripard@bootlin.com>
Cc: Sean Paul <sean@poorly.run>
Link: https://patchwork.freedesktop.org/patch/msgid/20190704145054.5701-1-daniel.vetter@ffwll.ch

drm: Document code of conduct

freedesktop.org has adopted a formal&enforced code of conduct:

https://www.fooishbar.org/blog/fdo-contributor-covenant/
https://www.freedesktop.org/wiki/CodeOfConduct/

Besides formalizing things a bit more I don't think this changes
anything for us, we've already peer-enforced respectful and
constructive interactions since a long time. But it's good to document
things properly.

v2: Drop confusing note from commit message and clarify the grammer
(Chris, Alex and others).

Cc: Daniel Stone <daniels@collabora.com>
Cc: Keith Packard <keithp@keithp.com>
Cc: tfheen@err.no
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Reviewed-by: Daniel Stone <daniels@collabora.com>
Reviewed-by: Sumit Semwal <sumit.semwal@linaro.org>
Acked-by: Archit Taneja <architt@codeaurora.org>
Reviewed-by: Martin Peres <martin.peres@free.fr>
Acked-by: Thierry Reding <treding@nvidia.com>
Acked-by: Jani Nikula <jani.nikula@intel.com>
Acked-by: Vincent Abriou <vincent.abriou@st.com>
Acked-by: Neil Armstrong <narmstrong@baylibre.com>
Reviewed-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Acked-by: Brian Starkey <brian.starkey@arm.com>
Acked-by: Rob Clark <robdclark@gmail.com>
Reviewed-by: David Herrmann <dh.herrmann@gmail.com>
Acked-by: Sean Paul <seanpaul@chromium.org>
Reviewed-by: Harry Wentland <harry.wentland@amd.com>
Reviewed-by: Eric Anholt <eric@anholt.net>
Acked-by: Alex Deucher <alexander.deucher@amd.com>
Acked-by: Gustavo Padovan <gustavo.padovan@collabora.com>
Acked-by: Michel Dänzer <michel.daenzer@amd.com>
Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Acked-by: Sumit Semwal <sumit.semwal@linaro.org>
Acked-by: Keith Packard <keithp@keithp.com>
Acked-by: Gabriel Krisman Bertazi <krisman@collabora.co.uk>
Acked-by: Adam Jackson <ajax@redhat.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>

drm/doc: Document feature merge deadlines

The discussion pretty much concluded without objections, let's
document what we agreed on.

Cc'ing linux-doc for the new tag in Documentation/process/index.rst.

Acked-by: Dave Airlie <airlied@gmail.com>
Reviewed-by: Sean Paul <seanpaul@chromium.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: linux-doc@vger.kernel.org
Cc: Dave Airlie <airlied@gmail.com>
Cc: Sean Paul <seanpaul@chromium.org>
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: Alex Deucher <alexdeucher@gmail.com>
Cc: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170321155228.30287-1-daniel.vetter@ffwll.ch

drm/doc: Add TODO list

This commit adds a TODO list to the GPU driver developer's guide. The
content was taken from the DRMJanitors page on the X.Org wiki:

https://www.x.org/wiki/DRMJanitors/

The goal is to track a list of refactorings that would be nice to see
merged eventually. Sometimes these would be encountered during patch
review on the mailing list, and at other times one can come across
these while working in a specific area of code.

Signed-off-by: Thierry Reding <treding@nvidia.com>
Acked-by: Sean Paul <seanpaul@chromium.org>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/20170207175113.2793-1-thierry.reding@gmail.com

drm/doc: Update styleguide

The new cool is &struct foo (kernel-doc now copes with linebreaks),
and structure members should be referenced using &foo.bar.

Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: David Herrmann <dh.herrmann@gmail.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/1483044517-5770-8-git-send-email-daniel.vetter@ffwll.ch

drm/doc: link style-guide to doc-guide

Our style guide should only be the delta compared to the overall one.

Cc: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1483008275-29383-1-git-send-email-daniel.vetter@ffwll.ch

Documentation/gpu: use recommended order of heading markers

While splitting the document up, the headings "shifted" from what pandoc
generated. Use the following order for headings for consistency:

==============
Document title
==============

First
=====

Second
------

Third
~~~~~

Leave the lower level headings as they are; I think those are less
important. Although RST doesn't mandate a specific order ("Rather than
imposing a fixed number and order of section title adornment styles, the
order enforced will be the order as encountered."), having the higher
levels the same overall makes it easier to follow the documents.

[I'm sort of kind of writing the recommendation for docs-next in the
mean time, but this order seems sensible, and is what I'm proposing.]

Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/126f42734defac6cbb8496a481d58db7b38461dd.1466506505.git.jani.nikula@intel.com

Documentation/gpu: split up the gpu documentation

Make the gpu documentation easier to manage by splitting to separate
files. Again, this is just the split, no real edits.

Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/bd2b599b5105c28c8f05923005e6cc9b7efa7fc1.1466506505.git.jani.nikula@intel.com