[PATCH] docs: document python version used for compilation

[Dmitry Baryshkov]

On Fri, 10 May 2024 at 13:09, Jani Nikula <jani.nikula at intel.com> wrote:
>
> On Fri, 10 May 2024, Mauro Carvalho Chehab <mchehab at kernel.org> wrote:
> > Em Fri, 10 May 2024 11:08:38 +0300
> > Jani Nikula <jani.nikula at intel.com> escreveu:
> >
> >> On Thu, 09 May 2024, Dmitry Baryshkov <dmitry.baryshkov at linaro.org> wrote:
> >> > The drm/msm driver had adopted using Python3 script to generate register
> >> > header files instead of shipping pre-generated header files. Document
> >> > the minimal Python version supported by the script.
> >> >
> >> > Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov at linaro.org>
> >> > ---
> >> >  Documentation/process/changes.rst | 1 +
> >> >  1 file changed, 1 insertion(+)
> >> >
> >> > diff --git a/Documentation/process/changes.rst b/Documentation/process/changes.rst
> >> > index 5685d7bfe4d0..8d225a9f65a2 100644
> >> > --- a/Documentation/process/changes.rst
> >> > +++ b/Documentation/process/changes.rst
> >> > @@ -63,6 +63,7 @@ cpio                   any              cpio --version
> >> >  GNU tar                1.28             tar --version
> >> >  gtags (optional)       6.6.5            gtags --version
> >> >  mkimage (optional)     2017.01          mkimage --version
> >> > +Python (optional)      3.5.x            python3 --version
> >>
> >> Python 3.5 reached end-of-life 3½ years ago [1]. What's the point in
> >> using anything older than the oldest supported version of Python,
> >> i.e. 3.8 at this time?
> >
> > What's the point of breaking compilation with on older distros?
> > The idea of minimal versions here is to specify the absolute minimum
> > version that it is required for the build to happen. If 3.5 is
> > the minimal one, then be it.
>
> AFAICT 3.5 was an arbitrary rather than a deliberate choice. We should
> at least be aware *why* we'd be sticking to old versions.

>From my side, the 3.5 was chosen basing on the previous feedback from
Jon Hunter: https://lore.kernel.org/dri-devel/20240412165407.42163-1-jonathanh@nvidia.com/

After checking distros that I can easily use, I don't think I will be
able to test the script with Python versions earlier than 3.7.3
(Debian oldoldstable).
I can try setting up Debian stretch (old-old-old-stable), which has
Python 3.5 and so cover the needs of Jon.

>
> Minimum versions here also means sticking to features available in said
> versions, for Python just as well as for GCC or any other tool. That's
> not zero cost.
>
> I guess there are two angles here too. The absolute minimum version
> currently required, and the, uh, maximum the minimum version can be
> safely bumped to. Say, you want to use a feature not available in the
> current minimum, how far up can you bump the version to?
>
> Could we define and document the criteria (e.g. based on distros as you
> suggest below) so we don't have to repeat the discussion?
>
>
> BR,
> Jani.
>
> >
> > -
> >
> > Now, a criteria is needed to raise the minimal version. IMO, the
> > minimal version shall be at least the minimal one present on most
> > used LTS distros that are not EOL.
> >
> > I would look for at least 4 such distros:
> >
> > - Debian
> >
> >   Looking at https://wiki.debian.org/LTS, Debian 10 EOL will be on
> >   June, 2024.
> >
> >   Looking at:
> >
> >       https://distrowatch.com/table.php?distribution=debian
> >
> >   Debian 10 uses python 3.7.3.
> >
> > - Looking at Distrowatch for openSUSE Leap 15.5, it uses Python
> >   3.6.15 and has an EOL schedule for Dec, 2024.
> >
> > - RHEL 8.9 uses a bigger version than those two - 3.11.5 - again
> >   looking at Distrowatch to check it.
> >
> > - SLES 15 SP4 and above uses Python 3.11, according with:
> >   https://www.suse.com/c/python-3-11-stack-for-suse-linux-enterprise-15/
> >
> > From the above, IMO kernel shall support building with Python 3.6
> > at least until the end of this year.
> >
> > Regards,
> > Mauro
>
> --
> Jani Nikula, Intel



-- 
With best wishes
Dmitry