[yocto] How do I patch the kernel before it is built?

[Darren Hart]

Autif,

All good questions. I'm traveling right now and don't know the answers
off the top of my head. I'd try module_autoload and see if that does
what you want. I'll be back briefly next week and then off to ELC. I
should be able to assist next week though if you don't resolve this on
your own. I don't believe this is documented. We need to resolve that.
The "how do I" is a reasonable start, but ultimately it needs to be in
some combination of the BSP Guide, the Kernel Arch manual, and the
Developers Manual.

--
Darren

On 02/08/2012 07:31 AM, autif khan wrote:
>>>> I have a meta layer where I am keeping my changes. I am guessing that I need to:
>>>>
>>>> a) write a bbappend file to accomplish #1
>>>> b) write a recipe to accomplish #3
>>>>
>>>> I have written recipes before, but just for libraries and autotools
>>>> based applications. Not for a kernel module. If there is a recipe out
>>>> there for some other module, I would be happy to steal from it.
>>>>
>>>> Please advise how I can go about patching the kernel and if there is a
>>>
>>> It's just like any other package. If your changes are simple, then
>>> generating patches and putting them on the SRC_URI via a bbappend in
>>> your layer is all you need. If you have complex changes, there are options
>>> to manage them via git or via feature descriptions.
>>>
>>>> recipe for a kernel module - please point me to it.
>>>
>>> Darren validated and updated the kernel module example, so he'd probably
>>> got this closer at hand than I do.
>>
>> See the hello-mod example under meta/recipes-kernel/hello-mod
> 
> Now, I want to load my module at startup.
> 
> The preferred way to load my module at startup would be by to place a
> file called hello-mod in /etc/modutils
> 
> Is this correct?
> 
> Is there a recipe already that does this?
> 
> I see this line in kernel.bbclass - module_autoload_ipv6 = "ipv6"
> 
> So will appending module_autoload_hello-mod = "hello-mod" to this
> class achieve this? I know how to append a recipe, but how do I append
> a class?
> 
> When I boot my device it seems like minix and ipv6 modules are loaded,
> but I can not follow how they are loaded.
> 
> Seems like ipv6 is in /etc/modutils, but minix is not.
> 
> minix is in /etc/filesystems - but I am not sure what role that file plays
> 
> Last but, not the least - was this documented somewhere and I just
> could not/did not find it? Should I add this to the "How do I ..."
> section of the wiki?
> 
> Thanks
> 
> Autif

-- 
Darren Hart
Intel Open Source Technology Center
Yocto Project - Linux Kernel