[meta-raspberrypi] how to apply custom kernel configuration?

[meta-raspberrypi] how to apply custom kernel configuration?

[Andrea Galbusera]

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Hi!

I was wondering how to apply some extra kernel configuration from a custom
layer via a bbappend. I know that with meta-raspberrypi there exist some
variables you can define in local.conf that will drive how the kernel is
configured: but what about some very specific device driver nobody than me
is interest in? To me it seems it doesn't deserve a dedicated global oe
variable.

Some investigation showed this topic already came up on the list from time
to time in the past (most recently in [1]). To me it looks like there is
some common desire to get rid of the current "magic" carried out by
linux-rpi.inc by moving the linux-raspberrypi recipes into the
configuration fragments style.

In the short term, my question are: how do you guys manage to add your
custom kernel configurations? Do you rely on full blown static defconfigs?
Have you found any reliable way to do "differential" configurations with
the current state of metadata?

In a longer term, I'd really like to help moving towards supporting
configuration fragments for linux-raspberrypi, but I suspect it'd be a too
much hard task for my current understanding of the whole kernel
configuration workflow. Do you know of anyone already working on this or
does anyone have a clear idea of what is needed to get the work done? Some
times ago I tried to resurrect [2], but with no luck, probably due to some
changes that happened in the linux-yocto files in the meanwhile.

Comments from gurus are welcome! ;-)

[1] https://lists.yoctoproject.org/pipermail/yocto/2016-December/033559.html
[2] https://lists.yoctoproject.org/pipermail/yocto/2015-October/027034.html

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Re: [meta-raspberrypi] how to apply custom kernel configuration?

[Khem Raj]

On Sat, May 6, 2017 at 9:45 AM, Andrea Galbusera <gizero@gmail.com> wrote:
> Hi!
>
> I was wondering how to apply some extra kernel configuration from a custom
> layer via a bbappend. I know that with meta-raspberrypi there exist some
> variables you can define in local.conf that will drive how the kernel is
> configured: but what about some very specific device driver nobody than me
> is interest in? To me it seems it doesn't deserve a dedicated global oe
> variable.
>
> Some investigation showed this topic already came up on the list from time
> to time in the past (most recently in [1]). To me it looks like there is
> some common desire to get rid of the current "magic" carried out by
> linux-rpi.inc by moving the linux-raspberrypi recipes into the configuration
> fragments style.
>
> In the short term, my question are: how do you guys manage to add your
> custom kernel configurations? Do you rely on full blown static defconfigs?
> Have you found any reliable way to do "differential" configurations with the
> current state of metadata?
>
> In a longer term, I'd really like to help moving towards supporting
> configuration fragments for linux-raspberrypi, but I suspect it'd be a too
> much hard task for my current understanding of the whole kernel
> configuration workflow. Do you know of anyone already working on this or
> does anyone have a clear idea of what is needed to get the work done? Some
> times ago I tried to resurrect [2], but with no luck, probably due to some
> changes that happened in the linux-yocto files in the meanwhile.
>
> Comments from gurus are welcome! ;-)

I have been hinting at using yocto kernel tooling. Idea is worth a pull request
care sending one ?

>
> [1] https://lists.yoctoproject.org/pipermail/yocto/2016-December/033559.html
> [2] https://lists.yoctoproject.org/pipermail/yocto/2015-October/027034.html
>
> --
> _______________________________________________
> yocto mailing list
> yocto@yoctoproject.org
> https://lists.yoctoproject.org/listinfo/yocto
>

Re: [meta-raspberrypi] how to apply custom kernel configuration?

[Andrei Gherzan]

On Sat, May 6, 2017 at 6:14 PM, Khem Raj <raj.khem@gmail.com> wrote:
> On Sat, May 6, 2017 at 9:45 AM, Andrea Galbusera <gizero@gmail.com> wrote:
>> Hi!
>>
>> I was wondering how to apply some extra kernel configuration from a custom
>> layer via a bbappend. I know that with meta-raspberrypi there exist some
>> variables you can define in local.conf that will drive how the kernel is
>> configured: but what about some very specific device driver nobody than me
>> is interest in? To me it seems it doesn't deserve a dedicated global oe
>> variable.
>>
>> Some investigation showed this topic already came up on the list from time
>> to time in the past (most recently in [1]). To me it looks like there is
>> some common desire to get rid of the current "magic" carried out by
>> linux-rpi.inc by moving the linux-raspberrypi recipes into the configuration
>> fragments style.
>>
>> In the short term, my question are: how do you guys manage to add your
>> custom kernel configurations? Do you rely on full blown static defconfigs?
>> Have you found any reliable way to do "differential" configurations with the
>> current state of metadata?
>>
>> In a longer term, I'd really like to help moving towards supporting
>> configuration fragments for linux-raspberrypi, but I suspect it'd be a too
>> much hard task for my current understanding of the whole kernel
>> configuration workflow. Do you know of anyone already working on this or
>> does anyone have a clear idea of what is needed to get the work done? Some
>> times ago I tried to resurrect [2], but with no luck, probably due to some
>> changes that happened in the linux-yocto files in the meanwhile.
>>
>> Comments from gurus are welcome! ;-)
>
> I have been hinting at using yocto kernel tooling. Idea is worth a pull request
> care sending one ?

I'm not using config fragments myself but I was under the impression
that we do support it.

--
Andrei Gherzan

Re: [meta-raspberrypi] how to apply custom kernel configuration?

[Bruce Ashfield]

On 2017-05-08 6:08 PM, Andrei Gherzan wrote:
> On Sat, May 6, 2017 at 6:14 PM, Khem Raj <raj.khem@gmail.com> wrote:
>> On Sat, May 6, 2017 at 9:45 AM, Andrea Galbusera <gizero@gmail.com> wrote:
>>> Hi!
>>>
>>> I was wondering how to apply some extra kernel configuration from a custom
>>> layer via a bbappend. I know that with meta-raspberrypi there exist some
>>> variables you can define in local.conf that will drive how the kernel is
>>> configured: but what about some very specific device driver nobody than me
>>> is interest in? To me it seems it doesn't deserve a dedicated global oe
>>> variable.
>>>
>>> Some investigation showed this topic already came up on the list from time
>>> to time in the past (most recently in [1]). To me it looks like there is
>>> some common desire to get rid of the current "magic" carried out by
>>> linux-rpi.inc by moving the linux-raspberrypi recipes into the configuration
>>> fragments style.
>>>
>>> In the short term, my question are: how do you guys manage to add your
>>> custom kernel configurations? Do you rely on full blown static defconfigs?
>>> Have you found any reliable way to do "differential" configurations with the
>>> current state of metadata?
>>>
>>> In a longer term, I'd really like to help moving towards supporting
>>> configuration fragments for linux-raspberrypi, but I suspect it'd be a too
>>> much hard task for my current understanding of the whole kernel
>>> configuration workflow. Do you know of anyone already working on this or
>>> does anyone have a clear idea of what is needed to get the work done? Some
>>> times ago I tried to resurrect [2], but with no luck, probably due to some
>>> changes that happened in the linux-yocto files in the meanwhile.
>>>
>>> Comments from gurus are welcome! ;-)
>>
>> I have been hinting at using yocto kernel tooling. Idea is worth a pull request
>> care sending one ?
>
> I'm not using config fragments myself but I was under the impression
> that we do support it.

Also FWIW, I've had a feature around for quite a while that I'll
complete in the 2.4 release cycle. That feature pulls the core fragment
processing into the main kernel classes (with auditing, etc, still in
kernel-yocto).

So doing an inherit of kernel-yocto won't be necessary at that point
.. which may ease the introduction of some config fragments.

Bruce

>
> --
> Andrei Gherzan
>