[PATCH v4 1/2] init/Kconfig: add python3 availability config

[PATCH v4 1/2] init/Kconfig: add python3 availability config

[Petr Vorel]

It will be used in the next commit for DRM_MSM.

Suggested-by: Rob Clark <robdclark@gmail.com>
Signed-off-by: Petr Vorel <pvorel@suse.cz>
---
Changes v3->v4:
* Move definition to the end of the file

 init/Kconfig | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/init/Kconfig b/init/Kconfig
index fbd0cb06a50a..c77e45484e81 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -2047,3 +2047,6 @@ config ARCH_HAS_SYNC_CORE_BEFORE_USERMODE
 # <asm/syscall_wrapper.h>.
 config ARCH_HAS_SYSCALL_WRAPPER
 	def_bool n
+
+config HAVE_PYTHON3
+	def_bool $(success,$(PYTHON3) -V)
-- 
2.45.2

[PATCH v4 2/2] drm/msm: depend on python3

[Petr Vorel]

0fddd045f88e introduced python3 dependency, use HAVE_PYTHON3 to make it
obvious.

Signed-off-by: Petr Vorel <pvorel@suse.cz>
---
Changes v3->v4:
* The same as in v3.

 drivers/gpu/drm/msm/Kconfig | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/gpu/drm/msm/Kconfig b/drivers/gpu/drm/msm/Kconfig
index 90c68106b63b..03ea0c83f11e 100644
--- a/drivers/gpu/drm/msm/Kconfig
+++ b/drivers/gpu/drm/msm/Kconfig
@@ -11,6 +11,7 @@ config DRM_MSM
 	depends on QCOM_LLCC || QCOM_LLCC=n
 	depends on QCOM_COMMAND_DB || QCOM_COMMAND_DB=n
 	depends on PM
+	depends on HAVE_PYTHON3
 	select IOMMU_IO_PGTABLE
 	select QCOM_MDT_LOADER if ARCH_QCOM
 	select REGULATOR
-- 
2.45.2

Re: [PATCH v4 1/2] init/Kconfig: add python3 availability config

[Masahiro Yamada]

On Thu, Nov 21, 2024 at 5:41 AM Petr Vorel <pvorel@suse.cz> wrote:
>
> It will be used in the next commit for DRM_MSM.
>
> Suggested-by: Rob Clark <robdclark@gmail.com>
> Signed-off-by: Petr Vorel <pvorel@suse.cz>
> ---
> Changes v3->v4:
> * Move definition to the end of the file


I prefer to not check the tool.

Why don't you install python3?




>  init/Kconfig | 3 +++
>  1 file changed, 3 insertions(+)
>
> diff --git a/init/Kconfig b/init/Kconfig
> index fbd0cb06a50a..c77e45484e81 100644
> --- a/init/Kconfig
> +++ b/init/Kconfig
> @@ -2047,3 +2047,6 @@ config ARCH_HAS_SYNC_CORE_BEFORE_USERMODE
>  # <asm/syscall_wrapper.h>.
>  config ARCH_HAS_SYSCALL_WRAPPER
>         def_bool n
> +
> +config HAVE_PYTHON3
> +       def_bool $(success,$(PYTHON3) -V)
> --
> 2.45.2
>


-- 
Best Regards
Masahiro Yamada

Re: [PATCH v4 1/2] init/Kconfig: add python3 availability config

[Petr Vorel]

> On Thu, Nov 21, 2024 at 5:41 AM Petr Vorel <pvorel@suse.cz> wrote:

> > It will be used in the next commit for DRM_MSM.

> > Suggested-by: Rob Clark <robdclark@gmail.com>
> > Signed-off-by: Petr Vorel <pvorel@suse.cz>
> > ---
> > Changes v3->v4:
> > * Move definition to the end of the file


> I prefer to not check the tool.

Ack.

> Why don't you install python3?

Everybody installs it when it's required, the question is how to inform about
the dependency.

There build environments are minimal environments:
* chroot (e.g. cross compilation)
* container

These are used by both developers and distros.

Kind regards,
Petr

> >  init/Kconfig | 3 +++
> >  1 file changed, 3 insertions(+)

> > diff --git a/init/Kconfig b/init/Kconfig
> > index fbd0cb06a50a..c77e45484e81 100644
> > --- a/init/Kconfig
> > +++ b/init/Kconfig
> > @@ -2047,3 +2047,6 @@ config ARCH_HAS_SYNC_CORE_BEFORE_USERMODE
> >  # <asm/syscall_wrapper.h>.
> >  config ARCH_HAS_SYSCALL_WRAPPER
> >         def_bool n
> > +
> > +config HAVE_PYTHON3
> > +       def_bool $(success,$(PYTHON3) -V)
> > --
> > 2.45.2

Re: [PATCH v4 1/2] init/Kconfig: add python3 availability config

[Rob Clark]

On Wed, Nov 20, 2024 at 5:17 PM Petr Vorel <pvorel@suse.cz> wrote:
>
> > On Thu, Nov 21, 2024 at 5:41 AM Petr Vorel <pvorel@suse.cz> wrote:
>
> > > It will be used in the next commit for DRM_MSM.
>
> > > Suggested-by: Rob Clark <robdclark@gmail.com>
> > > Signed-off-by: Petr Vorel <pvorel@suse.cz>
> > > ---
> > > Changes v3->v4:
> > > * Move definition to the end of the file
>
>
> > I prefer to not check the tool.
>
> Ack.
>
> > Why don't you install python3?
>
> Everybody installs it when it's required, the question is how to inform about
> the dependency.
>
> There build environments are minimal environments:
> * chroot (e.g. cross compilation)
> * container
>
> These are used by both developers and distros.

I don't think py3 is an _onerous_ dependency, but it has come up as a
surprise in minimal distro build environments at least once.. so I'd
be a fan of surfacing this dependency in a predictable/understandable
way (ie. I'm in favor of this patchset)

BR,
-R

> Kind regards,
> Petr
>
> > >  init/Kconfig | 3 +++
> > >  1 file changed, 3 insertions(+)
>
> > > diff --git a/init/Kconfig b/init/Kconfig
> > > index fbd0cb06a50a..c77e45484e81 100644
> > > --- a/init/Kconfig
> > > +++ b/init/Kconfig
> > > @@ -2047,3 +2047,6 @@ config ARCH_HAS_SYNC_CORE_BEFORE_USERMODE
> > >  # <asm/syscall_wrapper.h>.
> > >  config ARCH_HAS_SYSCALL_WRAPPER
> > >         def_bool n
> > > +
> > > +config HAVE_PYTHON3
> > > +       def_bool $(success,$(PYTHON3) -V)
> > > --
> > > 2.45.2

Re: [PATCH v4 1/2] init/Kconfig: add python3 availability config

[Masahiro Yamada]

On Thu, Nov 21, 2024 at 10:49 AM Rob Clark <robdclark@gmail.com> wrote:
>
> On Wed, Nov 20, 2024 at 5:17 PM Petr Vorel <pvorel@suse.cz> wrote:
> >
> > > On Thu, Nov 21, 2024 at 5:41 AM Petr Vorel <pvorel@suse.cz> wrote:
> >
> > > > It will be used in the next commit for DRM_MSM.
> >
> > > > Suggested-by: Rob Clark <robdclark@gmail.com>
> > > > Signed-off-by: Petr Vorel <pvorel@suse.cz>
> > > > ---
> > > > Changes v3->v4:
> > > > * Move definition to the end of the file
> >
> >
> > > I prefer to not check the tool.
> >
> > Ack.
> >
> > > Why don't you install python3?
> >
> > Everybody installs it when it's required, the question is how to inform about
> > the dependency.
> >
> > There build environments are minimal environments:
> > * chroot (e.g. cross compilation)
> > * container
> >
> > These are used by both developers and distros.
>
> I don't think py3 is an _onerous_ dependency, but it has come up as a
> surprise in minimal distro build environments at least once.. so I'd
> be a fan of surfacing this dependency in a predictable/understandable
> way (ie. I'm in favor of this patchset)


"once" is a keyword here.

"/bin/sh: python3: not found" provides sufficient information
about why the compilation failed, and you know what to do
to fix the problem.
This is good.


If you hide CONFIG_DRM_MSM silently
due to missing python3, you may scratch your head
"why drm/msm was not compiled?".
This is worse.








--
Best Regards
Masahiro Yamada

Re: [PATCH v4 1/2] init/Kconfig: add python3 availability config

[Petr Vorel]

> On Thu, Nov 21, 2024 at 10:49 AM Rob Clark <robdclark@gmail.com> wrote:

> > On Wed, Nov 20, 2024 at 5:17 PM Petr Vorel <pvorel@suse.cz> wrote:

> > > > On Thu, Nov 21, 2024 at 5:41 AM Petr Vorel <pvorel@suse.cz> wrote:

> > > > > It will be used in the next commit for DRM_MSM.

> > > > > Suggested-by: Rob Clark <robdclark@gmail.com>
> > > > > Signed-off-by: Petr Vorel <pvorel@suse.cz>
> > > > > ---
> > > > > Changes v3->v4:
> > > > > * Move definition to the end of the file


> > > > I prefer to not check the tool.

> > > Ack.

> > > > Why don't you install python3?

> > > Everybody installs it when it's required, the question is how to inform about
> > > the dependency.

> > > There build environments are minimal environments:
> > > * chroot (e.g. cross compilation)
> > > * container

> > > These are used by both developers and distros.

> > I don't think py3 is an _onerous_ dependency, but it has come up as a
> > surprise in minimal distro build environments at least once.. so I'd
> > be a fan of surfacing this dependency in a predictable/understandable
> > way (ie. I'm in favor of this patchset)


> "once" is a keyword here.

> "/bin/sh: python3: not found" provides sufficient information
> about why the compilation failed, and you know what to do
> to fix the problem.
> This is good.

> If you hide CONFIG_DRM_MSM silently
> due to missing python3, you may scratch your head
> "why drm/msm was not compiled?".
It's not on the list, but still visible in help (via search).

> This is worse.

I'm ok with this being refused. Yes, it's a trivial thing to find that python3
is not installed. I wasn't sure myself if this is really better. Having
something like "requires $(PYTHON3)" would be best solution (e.g. not disable
the config, but exit before starting to build), but of course unless this
feature is needed for many modules it does not make sense to have it.
It's because kernel mostly contains everything (unless languages like python
or any other dependency starts to be added). For this reason I like that
mconf-cfg.sh warns when missing ncurses devel files (even suggesting package
names).

Just to explain what was my motivation. CONFIG_DRM_MSM in in arm64 defconfig,
thus it will affect anybody who uses the defconfig (any distro will need to add
it).

It's needed only for Qualcomm arm64 devices only. But only for these devices
which are mainlined enough to really use CONFIG_DRM_MSM (many of them aren't in
that state).

postmarketOS is the distribution which supports Qualcomm. It stores kernel
config for each device and devices often have individual maintainer. E.g. 175x
"once" :).

Kind regards,
Petr

Re: [PATCH v4 1/2] init/Kconfig: add python3 availability config

[Masahiro Yamada]

On Sat, Nov 23, 2024 at 5:42 AM Petr Vorel <pvorel@suse.cz> wrote:
>
> > On Thu, Nov 21, 2024 at 10:49 AM Rob Clark <robdclark@gmail.com> wrote:
>
> > > On Wed, Nov 20, 2024 at 5:17 PM Petr Vorel <pvorel@suse.cz> wrote:
>
> > > > > On Thu, Nov 21, 2024 at 5:41 AM Petr Vorel <pvorel@suse.cz> wrote:
>
> > > > > > It will be used in the next commit for DRM_MSM.
>
> > > > > > Suggested-by: Rob Clark <robdclark@gmail.com>
> > > > > > Signed-off-by: Petr Vorel <pvorel@suse.cz>
> > > > > > ---
> > > > > > Changes v3->v4:
> > > > > > * Move definition to the end of the file
>
>
> > > > > I prefer to not check the tool.
>
> > > > Ack.
>
> > > > > Why don't you install python3?
>
> > > > Everybody installs it when it's required, the question is how to inform about
> > > > the dependency.
>
> > > > There build environments are minimal environments:
> > > > * chroot (e.g. cross compilation)
> > > > * container
>
> > > > These are used by both developers and distros.
>
> > > I don't think py3 is an _onerous_ dependency, but it has come up as a
> > > surprise in minimal distro build environments at least once.. so I'd
> > > be a fan of surfacing this dependency in a predictable/understandable
> > > way (ie. I'm in favor of this patchset)
>
>
> > "once" is a keyword here.
>
> > "/bin/sh: python3: not found" provides sufficient information
> > about why the compilation failed, and you know what to do
> > to fix the problem.
> > This is good.
>
> > If you hide CONFIG_DRM_MSM silently
> > due to missing python3, you may scratch your head
> > "why drm/msm was not compiled?".
> It's not on the list, but still visible in help (via search).
>
> > This is worse.
>
> I'm ok with this being refused. Yes, it's a trivial thing to find that python3
> is not installed. I wasn't sure myself if this is really better. Having
> something like "requires $(PYTHON3)" would be best solution (e.g. not disable
> the config, but exit before starting to build), but of course unless this
> feature is needed for many modules it does not make sense to have it.
> It's because kernel mostly contains everything (unless languages like python
> or any other dependency starts to be added). For this reason I like that
> mconf-cfg.sh warns when missing ncurses devel files (even suggesting package
> names).
>
> Just to explain what was my motivation. CONFIG_DRM_MSM in in arm64 defconfig,
> thus it will affect anybody who uses the defconfig (any distro will need to add
> it).


arch/arm64/configs/defconfig is a multi-platform config.

If CONFIG_DRM_MSM exists in arch/arm64/configs/defconfig
and if you want to build arm64 defconfig, you need to install
all necessary tools for that.



>
> It's needed only for Qualcomm arm64 devices only. But only for these devices
> which are mainlined enough to really use CONFIG_DRM_MSM (many of them aren't in
> that state).
>
> postmarketOS is the distribution which supports Qualcomm. It stores kernel
> config for each device and devices often have individual maintainer. E.g. 175x
> "once" :).


If you do not want to be bothered by unnecessary drivers,
you need to disable the relevant CONFIG option.
(e.g, scripts/config -d  CONFIG_DRM_MSM)


This is the standard way we have for many years.



--
Best Regards
Masahiro Yamada

Re: [PATCH v4 1/2] init/Kconfig: add python3 availability config

[Masahiro Yamada]

On Thu, Nov 21, 2024 at 10:17 AM Petr Vorel <pvorel@suse.cz> wrote:
>
> > On Thu, Nov 21, 2024 at 5:41 AM Petr Vorel <pvorel@suse.cz> wrote:
>
> > > It will be used in the next commit for DRM_MSM.
>
> > > Suggested-by: Rob Clark <robdclark@gmail.com>
> > > Signed-off-by: Petr Vorel <pvorel@suse.cz>
> > > ---
> > > Changes v3->v4:
> > > * Move definition to the end of the file
>
>
> > I prefer to not check the tool.
>
> Ack.
>
> > Why don't you install python3?
>
> Everybody installs it when it's required, the question is how to inform about
> the dependency.
>
> There build environments are minimal environments:
> * chroot (e.g. cross compilation)
> * container
>
> These are used by both developers and distros.


Documentation/process/changes.rst
documents basic tools necessary for building the kernel.

Python3 is listed as "optional" because it is required
only for some CONFIG options.

If the exact dependency is unclear, it is better to install
all tools listed in that table.




> Kind regards,
> Petr
>
> > >  init/Kconfig | 3 +++
> > >  1 file changed, 3 insertions(+)
>
> > > diff --git a/init/Kconfig b/init/Kconfig
> > > index fbd0cb06a50a..c77e45484e81 100644
> > > --- a/init/Kconfig
> > > +++ b/init/Kconfig
> > > @@ -2047,3 +2047,6 @@ config ARCH_HAS_SYNC_CORE_BEFORE_USERMODE
> > >  # <asm/syscall_wrapper.h>.
> > >  config ARCH_HAS_SYSCALL_WRAPPER
> > >         def_bool n
> > > +
> > > +config HAVE_PYTHON3
> > > +       def_bool $(success,$(PYTHON3) -V)
> > > --
> > > 2.45.2



-- 
Best Regards
Masahiro Yamada

Re: [PATCH v4 1/2] init/Kconfig: add python3 availability config

[Jani Nikula]

On Fri, 22 Nov 2024, Masahiro Yamada <masahiroy@kernel.org> wrote:
> Documentation/process/changes.rst
> documents basic tools necessary for building the kernel.
>
> Python3 is listed as "optional" because it is required
> only for some CONFIG options.
>
> If the exact dependency is unclear, it is better to install
> all tools listed in that table.

I think we're slightly in a limbo with the python build dependency. I
think it got initially merged a bit under the radar. And I don't mean to
imply any ill will here, it just didn't get the attention it maybe
should have. The dependency table got updated afterwards.

Now, what's the status for more modules depending on python? I for one
would like to use it for i915.ko, but I'm a bit uneasy about it as long
as it's "optional". Conversely, how many more users would we need to
switch the status from "optional" to "required"?


BR,
Jani.


-- 
Jani Nikula, Intel

Re: [PATCH v4 1/2] init/Kconfig: add python3 availability config

[Rob Clark]

On Fri, Nov 22, 2024 at 1:51 AM Jani Nikula <jani.nikula@linux.intel.com> wrote:
>
> On Fri, 22 Nov 2024, Masahiro Yamada <masahiroy@kernel.org> wrote:
> > Documentation/process/changes.rst
> > documents basic tools necessary for building the kernel.
> >
> > Python3 is listed as "optional" because it is required
> > only for some CONFIG options.
> >
> > If the exact dependency is unclear, it is better to install
> > all tools listed in that table.
>
> I think we're slightly in a limbo with the python build dependency. I
> think it got initially merged a bit under the radar. And I don't mean to
> imply any ill will here, it just didn't get the attention it maybe
> should have. The dependency table got updated afterwards.
>
> Now, what's the status for more modules depending on python? I for one
> would like to use it for i915.ko, but I'm a bit uneasy about it as long
> as it's "optional". Conversely, how many more users would we need to
> switch the status from "optional" to "required"?
>

The way I've been looking at it is, for drm gpu drivers, the
dependency is only a subset of the py that mesa depends on at build
time, and if you are wanting to build the KMD you almost certainly
want mesa as well.  Maybe the situation is different for kms-only
drivers or other subsystems.

I may be biased here, but being able to generate code/tables/etc at
build time is something that python is very useful for, and has been
used to great effect in mesa.  And because of mesa's dependency, it
seems like a reasonable dependency on the kernel side as well.  My
only question is how to make the dependency visible in the least
confusing way for both users and packagers.

BR,
-R

>
> BR,
> Jani.
>
>
> --
> Jani Nikula, Intel

Re: [PATCH v4 1/2] init/Kconfig: add python3 availability config

[Jani Nikula]

On Fri, 22 Nov 2024, Rob Clark <robdclark@gmail.com> wrote:
> I may be biased here, but being able to generate code/tables/etc at
> build time is something that python is very useful for, and has been
> used to great effect in mesa.

Agreed. I look at the list of required dependencies, and none of the
alternatives seem more appropriate for the task. Not having to worry
about hostprogs build is a bonus.

BR,
Jani.


-- 
Jani Nikula, Intel