Re: [PATCH 0/2] Add support for per-kernel recipe variants

["'cedric.hombourger@siemens.com' via isar-users" <isar-users@googlegroups.com>]

On Tue, 2025-04-08 at 10:09 +0200, Florian Bezdeka wrote:
> On Mon, 2025-04-07 at 09:01 -0700, chris.larson via isar-users wrote:
> > From: Christopher Larson <chris.larson@siemens.com>
> > 
> > Add support for per-kernel recipe variants. This aids in the
> > ability for a
> > MACHINE to support multiple kernels, by allowing us to generate
> > per-kernel
> > variants in recipes like external kernel modules.
> > 
> > A new variable KERNEL_NAMES will list the kernels for which
> > variants will be
> > generated. It defaults to KERNEL_NAME. While this variable lists
> > all supported
> > kernels for the current machine, a variant will not be generated
> > for
> > KERNEL_NAME, assuming that's the recipe's baseline. Each variant
> > listed in
> > KERNEL_NAMES will add kernel-<kernel_name> to the OVERRIDES
> > variable, and
> > per-kernel:<kernel_name> to the BBCLASSEXTEND variable. In
> > addition,
> > KERNEL_NAME will be set to the kernel name for the current variant.
> 
> I'm missing the documentation for the new `KERNEL_NAMES` variable.
> 
> In addition you explained how this works, but what is the use case
> behind? I can build multiple kernels per machine now, but when is
> this
> needed?

If you are wanting a concrete use-case noted in the documentation, it
can certainly be added: no harm.

Concretely there are machine-supporting layers offering multiple
kernels. Examples: "normal" kernel, PREEMPT_RT kernel. Another use-case
until we get a .deb for each .ko (like in Yocto you can get an ipk for
each ko), you may need a footprint-optimized kernel for e.g. a recovery
image.

I hope that explains. Do let us know if the use-cases should be listed
in the documentation. It would not be an issue to add them

> 
> > 
> > In a recipe that already uses KERNEL_NAME and appends it to its PN,
> > all you
> > need to do to use this is to inherit per-kernel, and add any
> > additional kernels
> > you want to support to KERNEL_NAMES. The second patch in this
> > series
> > does so for external kernel modules by default, but this will have
> > no effect
> > on existing recipes unless KERNEL_NAMES is set to something other
> > than
> > KERNEL_NAME.
> > 
> > Christopher Larson (2):
> >   per-kernel.bbclass: add class
> >   linux-module: inherit per-kernel
> > 
> >  meta/classes/per-kernel.bbclass             | 35
> > +++++++++++++++++++++
> >  meta/recipes-kernel/linux-module/module.inc |  2 +-
> >  2 files changed, 36 insertions(+), 1 deletion(-)
> >  create mode 100644 meta/classes/per-kernel.bbclass
> > 
> > -- 
> > 2.47.2
> 


-- 
You received this message because you are subscribed to the Google Groups "isar-users" group.
To unsubscribe from this group and stop receiving emails from it, send an email to isar-users+unsubscribe@googlegroups.com.
To view this discussion visit https://groups.google.com/d/msgid/isar-users/9d9b56bd32d249bb97e50a1447870a1a6438facf.camel%40siemens.com.