| Message ID | 20250531154900.53941-1-alperyasinak1@gmail.com |
|---|---|
| State | New |
| Headers | show |
| Series | ref-manual/variables.rst: document KERNEL_EXTRA_FEATURES | expand |
Hi Alper, On 5/31/25 5:49 PM, Alper Ak via lists.yoctoproject.org wrote: > Fix [YOCTO #15751] > > Signed-off-by: Alper Ak <alperyasinak1@gmail.com> > --- > documentation/ref-manual/variables.rst | 18 ++++++++++++++++++ > 1 file changed, 18 insertions(+) > > diff --git a/documentation/ref-manual/variables.rst b/documentation/ref-manual/variables.rst > index c697bdbbb..2f0925b15 100644 > --- a/documentation/ref-manual/variables.rst > +++ b/documentation/ref-manual/variables.rst > @@ -5202,6 +5202,24 @@ system and gives an overview of their function and contents. > Specifies additional ``make`` command-line arguments the OpenEmbedded > build system passes on when compiling the kernel. > > + :term:`KERNEL_EXTRA_FEATURES` > + Specifies optional kernel features to be added on top of the base > + configuration in kernel recipes that inherit the :ref:`ref-classes-kernel-yocto` class. > + I'm not sure that is true? git grep KERNEL_EXTRA_FEATURES meta/classes-recipe/kernel-yocto.bbclass returns nothing. Looking at the layer level, it seems KERNEL_EXTRA_FEATURES is never used as is, only as part of KERNEL_FEATURES, and always in final/leaf recipes and not .inc files or classes. > + This variable complements :term:`KERNEL_FEATURES` by allowing layers It doesn't as far as I could tell? You need to make KERNEL_EXTRA_FEATURES part of the KERNEL_FEATURES variable for that to be true? > + to include or override additional features without requiring Python code or > + recipe finalize hooks. > + > + Features are defined in ``.scc`` files, which serve as kernel :term:`Metadata` and usually include patches > + and configuration fragments to be used during the kernel build process to modify the Linux kernel. Gut feeling is that those two lines are too long but haven't checked myself, compare to other long lines in this file to see when we wrap text. > + For example:: > + > + KERNEL_EXTRA_FEATURES = "features/netfilter/netfilter.scc" > + KERNEL_FEATURES:append = " ${KERNEL_EXTRA_FEATURES}" > + > + By default, :term:`KERNEL_EXTRA_FEATURES` is empty. But, some distributions It's not, it simply doesn't exist that is all I believe? > + such as Poky may set a default value using a soft assignment (``?=``). Does it? I don't see it, only an :append is used. I'll let Antonin decide but I am not entirely sure it makes sense to document this variable, which is very recipe specific. A point could be made that since poky.conf modifies it, maybe it makes sense to document it :) Cheers, Quentin
Since the KERNEL_FEATURES variable is handled in kernel-yocto.bbclass and KERNEL_EXTRA_FEATURES is usually appended to it, I wanted to emphasize that this class should be used. That's why I made a connection between them and assumed that they were complementary. Apparently I misinterpreted it. As you said, it always in final/leaf recipes and not .inc files or classes. > > + such as Poky may set a default value using a soft assignment (``?=``). > Does it? I don't see it, only an :append is used. "bitbake-getvar KERNEL_EXTRA_FEATURES" shows that it is appended(:append) in poky.conf but somehow I missed it and wrote soft assign... my bad. I should be more careful :) > I'll let Antonin decide but I am not entirely sure it makes sense to > document this variable, which is very recipe specific. A point could be > made that since poky.conf modifies it, maybe it makes sense to document > it :) I can prepare a new patch based on your feedback, suggestions. Quentin Schulz <quentin.schulz@cherry.de>, 2 Haz 2025 Pzt, 14:36 tarihinde şunu yazdı: > > Hi Alper, > > On 5/31/25 5:49 PM, Alper Ak via lists.yoctoproject.org wrote: > > Fix [YOCTO #15751] > > > > Signed-off-by: Alper Ak <alperyasinak1@gmail.com> > > --- > > documentation/ref-manual/variables.rst | 18 ++++++++++++++++++ > > 1 file changed, 18 insertions(+) > > > > diff --git a/documentation/ref-manual/variables.rst b/documentation/ref-manual/variables.rst > > index c697bdbbb..2f0925b15 100644 > > --- a/documentation/ref-manual/variables.rst > > +++ b/documentation/ref-manual/variables.rst > > @@ -5202,6 +5202,24 @@ system and gives an overview of their function and contents. > > Specifies additional ``make`` command-line arguments the OpenEmbedded > > build system passes on when compiling the kernel. > > > > + :term:`KERNEL_EXTRA_FEATURES` > > + Specifies optional kernel features to be added on top of the base > > + configuration in kernel recipes that inherit the :ref:`ref-classes-kernel-yocto` class. > > + > > I'm not sure that is true? > > git grep KERNEL_EXTRA_FEATURES meta/classes-recipe/kernel-yocto.bbclass > > returns nothing. > > Looking at the layer level, it seems KERNEL_EXTRA_FEATURES is never used > as is, only as part of KERNEL_FEATURES, and always in final/leaf recipes > and not .inc files or classes. > > > + This variable complements :term:`KERNEL_FEATURES` by allowing layers > > It doesn't as far as I could tell? You need to make > KERNEL_EXTRA_FEATURES part of the KERNEL_FEATURES variable for that to > be true? > > > + to include or override additional features without requiring Python code or > > + recipe finalize hooks. > > + > > + Features are defined in ``.scc`` files, which serve as kernel :term:`Metadata` and usually include patches > > + and configuration fragments to be used during the kernel build process to modify the Linux kernel. > > Gut feeling is that those two lines are too long but haven't checked > myself, compare to other long lines in this file to see when we wrap text. > > > + For example:: > > + > > + KERNEL_EXTRA_FEATURES = "features/netfilter/netfilter.scc" > > + KERNEL_FEATURES:append = " ${KERNEL_EXTRA_FEATURES}" > > + > > + By default, :term:`KERNEL_EXTRA_FEATURES` is empty. But, some distributions > > It's not, it simply doesn't exist that is all I believe? > > > + such as Poky may set a default value using a soft assignment (``?=``). > > Does it? I don't see it, only an :append is used. > > I'll let Antonin decide but I am not entirely sure it makes sense to > document this variable, which is very recipe specific. A point could be > made that since poky.conf modifies it, maybe it makes sense to document > it :) > > Cheers, > Quentin
Hi, On Mon Jun 2, 2025 at 5:41 PM CEST, Alper Ak via lists.yoctoproject.org wrote: > Since the KERNEL_FEATURES variable is handled in kernel-yocto.bbclass > and KERNEL_EXTRA_FEATURES is usually appended to it, I wanted to > emphasize that this class should be used. > That's why I made a connection between them and assumed that they were > complementary. Apparently I misinterpreted it. As you said, it always > in final/leaf recipes and not .inc files or classes. > >> > + such as Poky may set a default value using a soft assignment (``?=``). >> Does it? I don't see it, only an :append is used. > > "bitbake-getvar KERNEL_EXTRA_FEATURES" shows that it is > appended(:append) in poky.conf but somehow I missed it and wrote soft I don't think we should document variable default values based on poky.conf, as Poky is only a reference distro after all. What bothers me is that KERNEL_EXTRA_FEATURES does not have any default value in the kernel-yocto class. And I don't see the added value compared to KERNEL_FEATURES, since what happens in the end is always: KERNEL_FEATURES:append = " ${KERNEL_EXTRA_FEATURES}" Meaning users are fine modifying the KERNEL_FEATURES variable directly, I believe. What do you think? Antonin
Looks like KERNEL_EXTRA_FEATURES only exists to add to KERNEL_FEATURES from poky. To be honest, after wrote the documentation I felt that this variable was unnecessary. Of course it's necessary for poky but you know what I mean. Antonin Godard <antonin.godard@bootlin.com>, 4 Haz 2025 Çar, 10:47 tarihinde şunu yazdı: > > Hi, > > On Mon Jun 2, 2025 at 5:41 PM CEST, Alper Ak via lists.yoctoproject.org wrote: > > Since the KERNEL_FEATURES variable is handled in kernel-yocto.bbclass > > and KERNEL_EXTRA_FEATURES is usually appended to it, I wanted to > > emphasize that this class should be used. > > That's why I made a connection between them and assumed that they were > > complementary. Apparently I misinterpreted it. As you said, it always > > in final/leaf recipes and not .inc files or classes. > > > >> > + such as Poky may set a default value using a soft assignment (``?=``). > >> Does it? I don't see it, only an :append is used. > > > > "bitbake-getvar KERNEL_EXTRA_FEATURES" shows that it is > > appended(:append) in poky.conf but somehow I missed it and wrote soft > > I don't think we should document variable default values based on poky.conf, as > Poky is only a reference distro after all. > > What bothers me is that KERNEL_EXTRA_FEATURES does not have any default value in > the kernel-yocto class. And I don't see the added value compared to > KERNEL_FEATURES, since what happens in the end is always: > > KERNEL_FEATURES:append = " ${KERNEL_EXTRA_FEATURES}" > > Meaning users are fine modifying the KERNEL_FEATURES variable directly, I > believe. What do you think? > > Antonin > > -- > Antonin Godard, Bootlin > Embedded Linux and Kernel engineering > https://bootlin.com >
diff --git a/documentation/ref-manual/variables.rst b/documentation/ref-manual/variables.rst index c697bdbbb..2f0925b15 100644 --- a/documentation/ref-manual/variables.rst +++ b/documentation/ref-manual/variables.rst @@ -5202,6 +5202,24 @@ system and gives an overview of their function and contents. Specifies additional ``make`` command-line arguments the OpenEmbedded build system passes on when compiling the kernel. + :term:`KERNEL_EXTRA_FEATURES` + Specifies optional kernel features to be added on top of the base + configuration in kernel recipes that inherit the :ref:`ref-classes-kernel-yocto` class. + + This variable complements :term:`KERNEL_FEATURES` by allowing layers + to include or override additional features without requiring Python code or + recipe finalize hooks. + + Features are defined in ``.scc`` files, which serve as kernel :term:`Metadata` and usually include patches + and configuration fragments to be used during the kernel build process to modify the Linux kernel. + For example:: + + KERNEL_EXTRA_FEATURES = "features/netfilter/netfilter.scc" + KERNEL_FEATURES:append = " ${KERNEL_EXTRA_FEATURES}" + + By default, :term:`KERNEL_EXTRA_FEATURES` is empty. But, some distributions + such as Poky may set a default value using a soft assignment (``?=``). + :term:`KERNEL_FEATURES` Includes additional kernel metadata. In the OpenEmbedded build system, the default Board Support Packages (BSPs)
Fix [YOCTO #15751] Signed-off-by: Alper Ak <alperyasinak1@gmail.com> --- documentation/ref-manual/variables.rst | 18 ++++++++++++++++++ 1 file changed, 18 insertions(+)