Python is listed as an optional dependency, but this is not
true, as:
1) CONFIG_LTO_CLANG runs a python script at scripts/Makefile.vmlinux_o;
2) kernel-doc is called during compilation when some DRM options
like CONFIG_DRM_I915_WERROR are enabled;
3) allyesconfig/allmodconfig will enable both.
So, better document that.
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
---
Documentation/process/changes.rst | 13 ++++++++++++-
1 file changed, 12 insertions(+), 1 deletion(-)
diff --git a/Documentation/process/changes.rst b/Documentation/process/changes.rst
index bccfa19b45df..f6abecf6da86 100644
--- a/Documentation/process/changes.rst
+++ b/Documentation/process/changes.rst
@@ -61,7 +61,7 @@ Sphinx\ [#f1]_ 3.4.3 sphinx-build --version
GNU tar 1.28 tar --version
gtags (optional) 6.6.5 gtags --version
mkimage (optional) 2017.01 mkimage --version
-Python (optional) 3.9.x python3 --version
+Python 3.9.x python3 --version
GNU AWK (optional) 5.1.0 gawk --version
====================== =============== ========================================
@@ -154,6 +154,17 @@ Perl
You will need perl 5 and the following modules: ``Getopt::Long``,
``Getopt::Std``, ``File::Basename``, and ``File::Find`` to build the kernel.
+Python
+------
+
+CONFIG_LTO_CLANG requires python 2.7 or 3.0+; some DRM config options like
+CONFIG_DRM_I915_WERROR require at least Python 2.7 or 3.4+.
+
+The kernel-doc tool and docs build require at least 3.6, but they depend on
+dict changes that happened on 3.7 to produce valid results.
+
+Other tools within the Kernel tree require newer versions.
+
BC
--
--
2.49.0[+CC Laurent and Jani]
Hi,
On Mon, 28 Jul 2025 16:54:29 +0200, Mauro Carvalho Chehab wrote:
> Python is listed as an optional dependency, but this is not
> true, as:
>
> 1) CONFIG_LTO_CLANG runs a python script at scripts/Makefile.vmlinux_o;
>
> 2) kernel-doc is called during compilation when some DRM options
> like CONFIG_DRM_I915_WERROR are enabled;
>
> 3) allyesconfig/allmodconfig will enable both.
Well, these conditions still sound to me optional.
>
> So, better document that.
>
> Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
> ---
> Documentation/process/changes.rst | 13 ++++++++++++-
> 1 file changed, 12 insertions(+), 1 deletion(-)
>
> diff --git a/Documentation/process/changes.rst b/Documentation/process/changes.rst
> index bccfa19b45df..f6abecf6da86 100644
> --- a/Documentation/process/changes.rst
> +++ b/Documentation/process/changes.rst
> @@ -61,7 +61,7 @@ Sphinx\ [#f1]_ 3.4.3 sphinx-build --version
> GNU tar 1.28 tar --version
> gtags (optional) 6.6.5 gtags --version
> mkimage (optional) 2017.01 mkimage --version
> -Python (optional) 3.9.x python3 --version
> +Python 3.9.x python3 --version
> GNU AWK (optional) 5.1.0 gawk --version
> ====================== =============== ========================================
>
> @@ -154,6 +154,17 @@ Perl
> You will need perl 5 and the following modules: ``Getopt::Long``,
> ``Getopt::Std``, ``File::Basename``, and ``File::Find`` to build the kernel.
>
> +Python
> +------
> +
> +CONFIG_LTO_CLANG requires python 2.7 or 3.0+; some DRM config options like
> +CONFIG_DRM_I915_WERROR require at least Python 2.7 or 3.4+.
> +
> +The kernel-doc tool and docs build require at least 3.6, but they depend on
> +dict changes that happened on 3.7 to produce valid results.
> +
> +Other tools within the Kernel tree require newer versions.
> +
These details look confusing in changes.rst. The table above says
python >=3.9.x. All you need to say here would just something lile:
+Python
+------
+
+Required with CONFIG_LTO_CLANG, some DRM config options like
+CONFIG_DRM_I915_WERROR, the kernel-doc tool, and docs build (Sphinx),
+among others.
Other details can go to comments in each script or other docs if
necessary.
Thanks, Akira
Em Tue, 29 Jul 2025 19:35:57 +0900 Akira Yokosawa <akiyks@gmail.com> escreveu: > [+CC Laurent and Jani] > > Hi, > > On Mon, 28 Jul 2025 16:54:29 +0200, Mauro Carvalho Chehab wrote: > > Python is listed as an optional dependency, but this is not > > true, as: > > > > 1) CONFIG_LTO_CLANG runs a python script at scripts/Makefile.vmlinux_o; > > > > 2) kernel-doc is called during compilation when some DRM options > > like CONFIG_DRM_I915_WERROR are enabled; > > > > 3) allyesconfig/allmodconfig will enable both. > > Well, these conditions still sound to me optional. Then we agree to disagree: if a missing package prevents building the kernel with allyesconfig/allmodconfig, IMO it is mandatory. In any case, as Jani pointed out, DRM_MSM, which is part of arm default configs also require Python. Building with clang also requires it on several archs. There are other parts that seem to require it, but I didn't dig into it. So, IMHO, even if you consider allmodconfig/allyesconfig as "optional", and you also consider clang as "optional" (it is marked as optional at changes), it is still mandatory for arm 32-bit most common config (multi_v7_defconfig) and for arm64 defconfig. It sounds pretty much mandatory to me: if a distro doesn't have it, it can't support arm architectures. IMO, it should not be tagged as optional there. At max, a note under Python description could mention what scenarios one still may not have it. Now, adding a note like that means that someone would need to be periodically updating it when people add more auto-generated stuff that may require it. > > So, better document that. > > > > Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org> > > --- > > Documentation/process/changes.rst | 13 ++++++++++++- > > 1 file changed, 12 insertions(+), 1 deletion(-) > > > > diff --git a/Documentation/process/changes.rst b/Documentation/process/changes.rst > > index bccfa19b45df..f6abecf6da86 100644 > > --- a/Documentation/process/changes.rst > > +++ b/Documentation/process/changes.rst > > @@ -61,7 +61,7 @@ Sphinx\ [#f1]_ 3.4.3 sphinx-build --version > > GNU tar 1.28 tar --version > > gtags (optional) 6.6.5 gtags --version > > mkimage (optional) 2017.01 mkimage --version > > -Python (optional) 3.9.x python3 --version > > +Python 3.9.x python3 --version > > GNU AWK (optional) 5.1.0 gawk --version > > ====================== =============== ======================================== > > > > @@ -154,6 +154,17 @@ Perl > > You will need perl 5 and the following modules: ``Getopt::Long``, > > ``Getopt::Std``, ``File::Basename``, and ``File::Find`` to build the kernel. > > > > +Python > > +------ > > + > > +CONFIG_LTO_CLANG requires python 2.7 or 3.0+; some DRM config options like > > +CONFIG_DRM_I915_WERROR require at least Python 2.7 or 3.4+. > > + > > +The kernel-doc tool and docs build require at least 3.6, but they depend on > > +dict changes that happened on 3.7 to produce valid results. > > + > > +Other tools within the Kernel tree require newer versions. > > + > > These details look confusing in changes.rst. The table above says > python >=3.9.x. All you need to say here would just something lile: > > +Python > +------ > + > +Required with CONFIG_LTO_CLANG, some DRM config options like > +CONFIG_DRM_I915_WERROR, the kernel-doc tool, and docs build (Sphinx), > +among others. > > Other details can go to comments in each script or other docs if > necessary. Maybe something like: Python ------ Several config options require it: it is required for arm/arm64 default configs, CONFIG_LTO_CLANG, some DRM optional configs, the kernel-doc tool, and docs build (Sphinx), among others. Regards, Mauro
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