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

[Darren Hart]

On 01/31/2012 08:51 AM, Bruce Ashfield wrote:
> On 12-01-31 11:45 AM, autif khan wrote:
>> I could not find a way to patch the kernel source before its is built.
>>
>> I promise to update the Yocto wiki's How do I section when I have a
>> working solution for the following :-)
> 
> This should be covered in the existing documentation and also the
> more general bitbake/oe-core docs.
> 
>>
>> Here is what I am trying to do:
>>
>> 1) Patch the kernel (add VID/PID to hid_ignore_list in
>> drivers/hid/hid-core.c and also to add the VID/PID to .h file)
>> 2) Build the kernel - no change here - standard kernel build
>> 3) Build a kernel module
>>
>> 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


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