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

Bruce Ashfield bruce.ashfield at windriver.com
Mon Feb 6 17:28:05 PST 2012 

On 12-02-06 8:20 PM, Bruce Ashfield wrote:
> On 12-02-06 5:10 PM, 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.
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>> 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.
>>>>>>
>>>>>>
>>>>>>
>>>>>> I tried this just now - here is what happens:
>>>>>>
>>>>>> Case - patch is in linux/linux-yocto/drivers/hid, SRC_URI ref is
>>>>>> file://drivers/hid/file.diff
>>>>>> Result: Fetcher failure for URL: 'file://drivers/hid/hid-core.c.diff
>>>>>
>>>>>
>>>>>
>>>>> If you get a fetcher failire, you have it in the wrong place.
>>>>>
>>>>> Note: this has nothing to do with the kernel and is a general
>>>>> bitbake/oe-core question.
>>>>>
>>>>>
>>>>>>
>>>>>> Case - patch is in linux/linux-yocto/drivers/hid, SRC_URI ref is
>>>>>> file://linux-yocto/drivers/hid/file.diff
>>>>>
>>>>>
>>>>>
>>>>> Interesting. I've never had to specify linux-yocto in my SRC_URIs,
>>>>> so something strange it going on here.
>>>>>
>>>>> Does anyone else have ideas here ?
>>>>>
>>>>>
>>>>>
>>>>>> Result - my diff files are copied in a directory called
>>>>>> linux-yocto in
>>>>>>
>>>>>>
>>>>>> tmp/work/crownbay-poky-linux/linux-yocto-3.0.4+git1+d05450e4aef02c1b7137398ab3a9f8f96da74f52_1+2247da9131ea7e46ed4766a69bb1353dba22f873-r3
>>>>>>
>>>>>>
>>>>>> These patches are not applied in
>>>>>>
>>>>>>
>>>>>> tmp/work/crownbay-poky-linux/linux-yocto-3.0.4+git1+d05450e4aef02c1b7137398ab3a9f8f96da74f52_1+2247da9131ea7e46ed4766a69bb1353dba22f873-r3/linux
>>>>>>
>>>>>>
>>>>>> Here is what the work directory looks like
>>>>>>
>>>>>>
>>>>>>
>>>>>> autif at fpbm:~/ssd/minimal/tmp/work/crownbay-poky-linux/linux-yocto-3.0.4+git1+d05450e4aef02c1b7137398ab3a9f8f96da74f52_1+2247da9131ea7e46ed4766a69bb1353dba22f873-r3$
>>>>>>
>>>>>> ls
>>>>>> git license-destdir linux linux-crownbay-standard-build linux-yocto
>>>>>> temp
>>>>>>
>>>>>>
>>>>>> autif at fpbm:~/ssd/minimal/tmp/work/crownbay-poky-linux/linux-yocto-3.0.4+git1+d05450e4aef02c1b7137398ab3a9f8f96da74f52_1+2247da9131ea7e46ed4766a69bb1353dba22f873-r3$
>>>>>>
>>>>>>
>>>>>>
>>>>>> I have attached the original set of files as a tar gzip.
>>>>>
>>>>>
>>>>>
>>>>> I'll take them for a spin.
>>>>>
>>>>>
>>>>>>
>>>>>>> (and yes, I see 'edison' was the branch now)
>>>>>>
>>>>>>
>>>>>>
>>>>>> Yes, I am using Yocto 1.0 - very soon I will migrate to M2 - pending
>>>>>> tasks at hand :-)
>>>>>
>>>>>
>>>>>
>>>>> I'll have to dig up a 1.0 tree, since I don't have anything of that
>>>>> vintage available to me.
>>>>>
>>>>> But I know that patched worked then, and am absolutely sure that it
>>>>> works in 1.1 and master.
>>>>
>>>>
>>>> OK, I switched to M2 release and now, I have a different error:
>>>>
>>>> Case - diff files are in recipes/linux/linux-yocto, SRC_URI is
>>>> file://drivers/hid/hid-core.c.diff
>>>> Result - ERROR: Function 'Fetcher failure for URL:
>>>> 'file://drivers/hid/hid-core.c.diff'. Unable to fetch URL
>>>> file://drivers/hid/hid-core.c.diff from any source.' failed
>>>>
>>>>
>>>> Did, I misunderstood you when you said that I should rename the files
>>>> dir to linux-yocto - the name of the recipe and remove it from the
>>>> SRC_URI?
>>>
>>>
>>> Every build that I do with my meta-kernel-dev has some out of tree
>>> patches. It's a form of continual regression testing that I do out
>>> of habit.
>>>
>>> My bbappend looks like this:
>>>
>>> SRC_URI =
>>> "git://${KSRC_linux_yocto};protocol=file;nocheckout=1;branch=${KBRANCH},meta;name=machine,meta
>>>
>>> \
>>> file://make.patch \
>>> file://subdir/make2.patch \
>>> file://subdir/make3.patch"
>>>
>>>
>>>> pwd
>>> /home/bruce/yocto/poky-extras/meta-kernel-dev/recipes-kernel/linux
>>>> tree linux-yocto
>>> linux-yocto
>>> ├── make.patch
>>> └── subdir
>>> ├── make2.patch
>>> └── make3.patch
>>>
>>> These are always applied to my build.
>>>
>>> Cheers,
>>>
>>> Bruce
>>>
>>
>> I will try that next. However, it seems like something is wrong with
>> my setup may be.
>>
>> I was reading the log.do_patch file and it seems like bitbake is
>> mixing my build and recipes directory.
>
> Thanks! I'll run some tests here and see what I can find.

A quick look at the patches themselves shows them to not be valid kernel
patches.

The files don't have the right sub-path, so there's no way you'll ever
patch the kernel with these changes. My suggestion is to make the changes,
commit them to your local tree (with a commit header) and then git 
format-patch
them out. Use that patch in your bbappend.

i.e. you have:

--- hid-ids.h.orig      2012-02-06 16:54:56.056357248 -0500
+++ hid-ids.h   2012-02-06 16:55:15.888365151 -0500

that needs to be something like:

--- a/drivers/hid/hid-ids.h.orig      2012-02-06 16:54:56.056357248 -0500
+++ b/drivers/hid/hid-ids.h   2012-02-06 16:55:15.888365151 -0500

before it every will have a chance to work.

To make the patches attempt to apply .. and fail, I did added this
to my linux-yocto_3.0.bbappend:

+
+SRC_URI += " file://drivers/hid/hid-core.c.diff \
+             file://drivers/hid/hid-ids.h.diff"

and put the patches in:


 > tree linux-yocto
linux-yocto
├── drivers
│   └── hid
│       ├── hid-core.c.diff
│       └── hid-ids.h.diff

Cheers,

Bruce


>
> Cheers,
>
> Bruce
>
>>
>> The recipe and logs are attached in this email. Once again, I have
>> switched to M2 now. This is no longer with Yocto 1.0.
>
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