Python is listed as an optional dependency, but this is not
true, as:

1) arm (multi_v7_defconfig and other defconfigs) and arm64 defconfig
   needs it due to DRM_MSM dependencies;

2) CONFIG_LTO_CLANG runs a python script at scripts/Makefile.vmlinux_o;

3) kernel-doc is called during compilation when some DRM options
   like CONFIG_DRM_I915_WERROR are enabled;

4) allyesconfig/allmodconfig will enable CONFIG_* dependencies
   that needs it;

5) besides DRM, other subsystems seem to have logic calling *.py
   scripts.

So, better document that and change the dependency from optional
to mandatory to reflect the current needs.

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
---
 Documentation/process/changes.rst | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/Documentation/process/changes.rst b/Documentation/process/changes.rst
index bccfa19b45df..4c9088e429c8 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 +154,13 @@ Perl
 You will need perl 5 and the following modules: ``Getopt::Long``,
 ``Getopt::Std``, ``File::Basename``, and ``File::Find`` to build the kernel.
 
+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.
+
 BC
 --
 
-- 
2.49.0

On Tue, Jul 29, 2025 at 11:44 AM Mauro Carvalho Chehab
<mchehab+huawei@kernel.org> wrote:
>
> Python is listed as an optional dependency, but this is not
> true, as:
>
> 1) arm (multi_v7_defconfig and other defconfigs) and arm64 defconfig
>    needs it due to DRM_MSM dependencies;
>
> 2) CONFIG_LTO_CLANG runs a python script at scripts/Makefile.vmlinux_o;
>
> 3) kernel-doc is called during compilation when some DRM options
>    like CONFIG_DRM_I915_WERROR are enabled;
>
> 4) allyesconfig/allmodconfig will enable CONFIG_* dependencies
>    that needs it;
>
> 5) besides DRM, other subsystems seem to have logic calling *.py
>    scripts.
>
> So, better document that and change the dependency from optional
> to mandatory to reflect the current needs.
>
> Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
> ---
>  Documentation/process/changes.rst | 9 ++++++++-
>  1 file changed, 8 insertions(+), 1 deletion(-)

DT schema checks requires it too.

Acked-by: Rob Herring (Arm) <robh@kernel.org>

On Tue, 29 Jul 2025 18:43:04 +0200, Mauro Carvalho Chehab wrote:
> Python is listed as an optional dependency, but this is not
> true, as:
> 
> 1) arm (multi_v7_defconfig and other defconfigs) and arm64 defconfig
>    needs it due to DRM_MSM dependencies;
> 
> 2) CONFIG_LTO_CLANG runs a python script at scripts/Makefile.vmlinux_o;
> 
> 3) kernel-doc is called during compilation when some DRM options
>    like CONFIG_DRM_I915_WERROR are enabled;
> 
> 4) allyesconfig/allmodconfig will enable CONFIG_* dependencies
>    that needs it;
> 
> 5) besides DRM, other subsystems seem to have logic calling *.py
>    scripts.
> 

OK. This sounds convincing enough.

> So, better document that and change the dependency from optional
> to mandatory to reflect the current needs.
> 
> Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
> ---
>  Documentation/process/changes.rst | 9 ++++++++-
>  1 file changed, 8 insertions(+), 1 deletion(-)
> 
> diff --git a/Documentation/process/changes.rst b/Documentation/process/changes.rst
> index bccfa19b45df..4c9088e429c8 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 +154,13 @@ Perl
>  You will need perl 5 and the following modules: ``Getopt::Long``,
>  ``Getopt::Std``, ``File::Basename``, and ``File::Find`` to build the kernel.
>  
> +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.
> +

Looks much better.  Feel free to add:

Acked-by: Akira Yokosawa <akiyks@gmail.com>

Thanks.