Re: [docs] [PATCH v2] ref-manual: document KERNEL_SPLIT_MODULES variable

["Antonin Godard" <antonin.godard@bootlin.com>]

On Wed Jun 18, 2025 at 3:19 PM CEST, Dixit Parmar via lists.yoctoproject.org wrote:
> On Wed, Jun 18, 2025 at 06:30 PM, Antonin Godard wrote:
>
>> 
>> On Wed Jun 18, 2025 at 2:14 PM CEST, Dixit Parmar via
>> lists.yoctoproject.org wrote:
>> 
>>> Will fix the ref->term typo and the take your suggestion on rewording.
>>> 
>>> There seem to be confusion related to the kernel package name, however I
>>> feel
>>> it was additional information. I shall remove the mention of the kernel
>>> package name (keep the variable reference only) for simplicity in next
>>> version.
>> 
>> Looking forward to it!
>> 
>> 
>>> Yes, you would be able to install "all" the kernel-modules without
>>> bothering
>>> about KERNEL_SPLIT_MODULES. The issue is having autoload .conf file being
>>> installed or not when KERNEL_MODULE_AUTOLOAD is having your modules listed
>>> to
>>> be autoloader. When KERNEL_SPLIT_MODULES = 0 the .conf files for driver
>>> autoload and probeconf is not getting generated.
>> 
>> This sounds like a bug to me, no? Why would someone expect setting
>> KERNEL_SPLIT_MODULES to 0 have the autoload files missing?
>> 
>> I ran a some tests. So when I set KERNEL_SPLIT_MODULES to 1, and
>> KERNEL_MODULE_AUTOLOAD to "xt_limit", a kernel-module-xt-limit.ipk package
>> is
>> generated like so:
>> 
>> ├── etc
>> │   └── modules-load.d
>> │   └── xt_limit.conf
>> └── lib
>> └── modules
>> └── 6.12.30-yocto-standard
>> └── kernel
>> └── net
>> └── netfilter
>> └── xt_limit.ko
>> 
>> When KERNEL_SPLIT_MODULES is set to 0, only one kernel-modules.ipk package
>> is
>> generated, and does _not_ contain xt_limit.conf, but only xt_limit.ko. To
>> me
>> this sounds like a bug, what do you think?
>
> Exactly, that's the issue reported https://bugzilla.yoctoproject.org/show_bug.cgi?id=15145 ( https://bugzilla.yoctoproject.org/show_bug.cgi?id=15145 ) and I am fixing it here with this solution https://lists.openembedded.org/g/openembedded-core/message/218290.
>
>> 
>> I would _not_ describe that behavior in the documentation for the
>> KERNEL_SPLIT_MODULES variables.
>
> True, that's why the documentation does not mention anything about the conf files.
>
>> 
>> The fact that "kernel-modules" is still available when
>> KERNEL_SPLIT_MODULES = 1
>> is simply because a "fake" kernel-modules.ipk package is generated, and
>> depends
>> on the other kernel-module-* packages - so you can ignore my remark in my
>> previous message.
>
> Which remark exactly??

About the possibility to install "kernel-modules" both when KERNEL_SPLIT_MODULES
is 0 or 1. I guess it doesn't hurt to add a note about that at the end of the
definition:

"""
.. note::

   If :term:`KERNEL_SPLIT_MODULES` is set to 0, it is still possible to install
   all kernel modules at once by adding ``kernel-modules`` to
   :term:`IMAGE_INSTALL`. The way it works is that a placeholder
   "kernel-modules" package will be created and will depend on every other
   individual kernel module packages.
"""

So there's no confusion. What do you think?

Antonin

-- 
Antonin Godard, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com