[Nouveau] [RFC] Documentation: nouveau: Introduce some nouveau documentation

[Jeremy Cline]

On Thu, Sep 24, 2020 at 07:26:01PM +0200, Karol Herbst wrote:
> On Thu, Sep 24, 2020 at 6:03 PM Jeremy Cline <jcline at redhat.com> wrote:
> >
> > On Wed, Sep 23, 2020 at 11:36:54PM +0200, Karol Herbst wrote:
> > > On Wed, Sep 23, 2020 at 10:39 PM Jeremy Cline <jcline at redhat.com> wrote:
> > > >
> > > > On Wed, Sep 23, 2020 at 09:02:45PM +0200, Karol Herbst wrote:
> > > > > On Fri, Sep 11, 2020 at 6:21 PM Jeremy Cline <jcline at redhat.com> wrote:
> > > >
> > > > <snip>
> > > >
> > > > > yeah, I think overall this file is a good idea and being able to get a
> > > > > quick overview over the driver is helpful. I think if we focus on the
> > > > > user facing things first, like the hwmon or other things users
> > > > > generally interact with would be helpful. I think if we start to
> > > > > document areas where there are many low hanging fruits, this could
> > > > > help random people to start with easier tasks and get more used to the
> > > > > driver overall, so I'd probably ignore most of the stuff which really
> > > > > requires a fundamental understanding on how things work and focus more
> > > > > on vbios parsing (which has annoying interfaces anyway and it might
> > > > > make sense to make it more consistent and nicer to use) and/or simple
> > > > > code interfacing with the mmio space.
> > > > >
> > > >
> > > > I'll admit to being motivated by entirely selfish reasons. I know
> > > > practically nothing about nouveau and I'm the type of person who likes
> > > > to keep notes about how things work together, both free form and
> > > > structured in-line docs. All that to say, I think focusing on the
> > > > "low-hanging fruit" stuff will be very beneficial and I'm happy to do
> > > > that, but I'm also interested in documenting everything else I run
> > > > across.
> > > >
> > >
> > > yeah, that's fine. I was just giving a suggestion on where the initial
> > > focus should be on.
> > >
> > > > > Eg some users have problems with their fans as they are either always
> > > > > ramping up to max, or not running at all... GPUs temperature or power
> > > > > consumption is reporting incorrectly... all those things users hit
> > > > > regularly, but which isn't really important enough so it just falls
> > > > > under the table even if it gets reported.
> > > > >
> > > >
> > > > This does bring up an interesting point about organization and target
> > > > audiences. Typically when I'm writing documentation I like to organize
> > > > things by target audiences, so we could have a layout like:
> > > >
> > > > * General Introduction
> > > >
> > > > * User Guide
> > > >     - Overview of supported hardware/features/etc
> > >
> > > That's best to document in a wiki though. And we had plans to convert
> > > the existing old wiki over to gitlab. And maybe It think we really
> > > should do that and clean it up while we work on that. It's just a huge
> > > project but maybe just starting with whatever you want to do would be
> > > fine and after a while nothing is left. Anyway, I think we should
> > > discuss this more openly with the others as well. i don't like the
> > > current wiki anyway, as only approved developers can change things and
> > > with a gitlab wiki we could even take MRs on stuff.
> > >
> >
> > Yeah, so I think there's going to be at least three separate locations
> > for documentation: Envytools (hardware), the nouveau wiki (user guide),
> > and in the kernel (developer-focused and only the kernel bits). I don't
> > know much about the userspace bits yet, so maybe there's going to be
> > more than three places. I think it'd be good to at least cross-reference
> > between the wiki and the kernel docs, so this "section" could really
> > just be a link to the nouveau wiki for folks who end up in the kernel
> > docs, but really just want to use things (and maybe new developers who
> > haven't historically been users, such as myself).
> >
> > > >     - Installation
> > >
> > > well.. I think this can be skipped ;) But still, also belongs more
> > > into a wiki. I think what we could cover here is to how to clean up
> > > remaining stuff from the blob driver as this is something which comes
> > > up quite a lot on IRC though.
> > >
> > > >     - Configuration (module parameters and such)
> > > >     - Troubleshooting
> > >
> > > that would be cool to have in the wiki as well. Just collecting the
> > > most common issue and document it there. Especially if it is on
> > > gitlab, users can just do that as well :)
> > >
> > > >     - Getting Involved (bug reporting, running tests, etc)
> > >
> > > yeah, and we have some stuff on that on the old wiki already, it's
> > > just very outdated and needs updating, which as said above can only be
> > > done by developers and developers sadly have other things to do :)
> > >
> > > >
> > > > * Developer Guide
> > > >     - Architecture Overview
> > > >     - External APIs (include/uapi/drm/nouveau_drm.h, any sysfs stuff)?
> > > >     - Internal APIs
> > >
> > > Right, those things I'd like to see in the kernel tree actually.
> > >
> > > >     - Debugging and Development Tools
> > > >     - Contribution Guide
> > > >
> > >
> > > Those I think belong more into the wiki again. The latter is a bit
> > > hard to split as there are kernel guides, but also community and
> > > project guides. Mesa does things differently than let's say the
> > > kernel. And Nouveau is still in this limbo state being on the old
> > > infra, but also on the new one with mesa...
> > >
> > > > I'm not sure how much stuff people want to keep on the
> > > > nouveau.freedesktop.org wiki vs here.
> > > >
> > >
> > > I think the first step actually is to set up a proper nouveau project
> > > on gitlab for dealing with issues and the wiki. I would be fine to do
> > > that and we can also move the code there late. But maybe let's start
> > > with the wiki :)
> > >
> >
> > I've got some experience with GitLab's wiki, and as far as I could tell
> > there wasn't a great way to handle contribution from folks without write
> > access as well as reviews (it may exist, I just don't know it) so what
> > I've done in the past is use GitLab Pages[0] and stored a Sphinx project
> > in the repository so contributions are through normal merge requests. I
> > don't know if gitlab.freedesktop.org has Pages set up, though.
> > Regardless, I'm more than happy to do that work as well.
> >
> 
> there might be an easier way. In gitlab you can actually mirror
> repositories. I created https://gitlab.freedesktop.org/nouveau/wiki
> and asked Daniels to set up a mirror against the wiki git repo of the
> same project. If we add some CI pipeline on top we could even verify
> the proposed changes are valid. Maybe that would be good enough...
> 
> But yeah.. maybe having a simple pages site would also work.. dunno if
> it actually makes a difference anyway, but that might be more work.
> 

The work is pretty minimal for what I typically do. You need a CI job to
build the docs on merge requests and pushes, which at its most verbose
is something like:

docs:
  stage: test
  before_script:
    # Pin Sphinx to a particular major version
    - python3 -m venv ~/docs-venv
    - source ~/docs-venv/bin/activate
    - pip install "sphinx<3"
    - pushd path/to/docs
  script: make SPHINXOPTS="-W" html
  artifacts:
    paths:
      - path/to/docs/_build/
  only:
    refs:
      - merge_requests
      - main

After that, you just deploy documentation changes to a particular branch
updates:

pages:
  stage: deploy
  dependencies:
    - docs
  script:
    - mv path/to/docs/_build/ public/
  artifacts:
    paths:
      - public
  only:
    refs:
      - main

And that's about it. This gives you CI that catches any incorrectly
formatted/invalid documentation, provide reviewers with easy-to-view
HTML versions of proposed docs in the merge request, and automatically
deploys updates when changes are pushed to the main branch.

Of course, my only real reason for preferring this approach is that I've
done it a couple times and I'm very familiar with Sphinx. I don't have
any objection to doing it a different way.

- Jeremy