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

[Bruce Ashfield]

On Mon, Feb 6, 2012 at 2:35 PM, autif khan <autif.mlist at gmail.com> 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.
>
> I tried this - attached at the end of this email are my bbappend file
> and my patches, when the recipe is bitbaked, it does not actually
> apply the patch.
>
> On a similar note - there seems to be a file in
> meta/recipes-kernel/linux/linux-yocto called
> tools-perf-no-scripting.patch
>
> However, it does not seem to be used anywhere - is this just crud or I
> am missing something? I was hoping to cheat off of the recipe that
> uses it.
>
>>>> 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
>
> Thank you for this recipe - it seems like this is exactly what I was
> looking for. I will cheat off of this as soon as I can patch my
> kernel.
>
>
> R E C I P E
>
> autif at fpbm:~/data/yocto/poky-edison-6.0/meta-koko/recipes/linux$ cat
> linux-yocto_3.0.bbappend
> FILESEXTRAPATHS_prepend := "${THISDIR}:"
> SRC_URI += " file://linux/drivers/hid/hid-core.c.diff \
>             file://linux/drivers/hid/hid-ids.h.diff "
> PR = "r3"
> autif at fpbm:~/data/yocto/poky-edison-6.0/meta-koko/recipes/linux$
>
> P A T C H
>
> autif at fpbm:~/data/yocto/poky-edison-6.0/meta-koko/recipes/linux/linux/drivers/hid$

Taking a look at this (while I was cutting and pasting), this should
be in in the
a 'linux-yocto' subdirectory if you want bitbake to pickup the patch and make it
available to the linux-yocto recipe.

i.e. ~/data/yocto/poky-edison-6.0/meta-koko/recipes/linux/linux-yocto/drivers/hid

And don't use 'linux-yocto' in your file:// reference on the SRC_URI,
that part is
automatic.

(and yes, I see 'edison' was the branch now)

Cheers,

Bruce

> cat hid-core.c.diff
> --- linux.orig/drivers/hid/hid-core.c   2012-01-31 16:44:44.152001877 -0500
> +++ linux/drivers/hid/hid-core.c        2012-01-31 16:46:34.608001870 -0500
> @@ -1839,6 +1839,8 @@
>        { HID_USB_DEVICE(USB_VENDOR_ID_WISEGROUP, USB_DEVICE_ID_1_PHIDGETSERVO_20) },
>        { HID_USB_DEVICE(USB_VENDOR_ID_WISEGROUP, USB_DEVICE_ID_8_8_4_IF_KIT) },
>        { HID_USB_DEVICE(USB_VENDOR_ID_YEALINK, USB_DEVICE_ID_YEALINK_P1K_P4K_B2K) },
> +       { HID_USB_DEVICE(USB_VENDOR_ID_PIXCIR, USB_DEVICE_ID_PIXCIR) },
>        { }
>  };
> autif at fpbm:~/data/yocto/poky-edison-6.0/meta-koko/recipes/linux/linux/drivers/hid$
> autif at fpbm:~/data/yocto/poky-edison-6.0/meta-koko/recipes/linux/linux/drivers/hid$
> cat hid-ids.h.diff--- linux.orig/drivers/hid/hid-ids.h  2012-01-31
> 16:44:55.432001877 -0500
> +++ linux/drivers/hid/hid-ids.h 2012-01-31 16:47:36.624001858 -0500
> @@ -671,4 +671,7 @@
>  #define USB_VENDOR_ID_ZYDACRON 0x13EC
>  #define USB_DEVICE_ID_ZYDACRON_REMOTE_CONTROL  0x0006
>
> +#define USB_VENDOR_ID_PIXCIR   0x040b
> +#define USB_DEVICE_ID_PIXCIR   0x2000
> +
>  #endif
> autif at fpbm:~/data/yocto/poky-edison-6.0/meta-koko/recipes/linux/linux/drivers/hid$
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