[PATCH] docs: document python version used for compilation

[Mauro Carvalho Chehab]

Em Fri, 10 May 2024 13:39:17 +0300
Dmitry Baryshkov <dmitry.baryshkov at linaro.org> escreveu:

> 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.

Fedora 40 supports version 3.6 and above (plus 2.7):
	https://developer.fedoraproject.org/tech/languages/python/multiple-pythons.html

You could do something similar with Ubuntu/Debian:
	https://askubuntu.com/questions/682869/how-do-i-install-a-different-python-version-using-apt-get

Once an old version is installed, you can enable it with:

	$ python3.6 -m venv v3.6  # create the environment
	$ . v3.6/bin/activate

Then, if needed, install whatever dependencies are needed with pip,
inside the venv (for instance if you want to also test Sphinx, you
can install it there via pip).

I guess it should be possible to use a similar venv procedure with
older versions, but you may need to compile it from the sources if
you don't have binaries available for your distro.

Regards,
Mauro