[PATCH 2/2] docs: changes: better document Python needs

[Mauro Carvalho Chehab <mchehab+huawei@kernel.org>]

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