[yocto] How to specify a machine defconfig for a linux recipe

[Bruce Ashfield]

On 12-05-03 06:03 PM, Denys Dmytriyenko wrote:
> On Thu, May 03, 2012 at 05:57:41PM -0400, Bruce Ashfield wrote:
>> On 12-05-03 05:42 PM, Elvis Dowson wrote:
>>> Hi,
>>>
>>> On May 3, 2012, at 9:55 PM, Elvis Dowson wrote:
>>>
>>>> How can I specify a machine defconfig for a linux recipe?
>>>>
>>>> For example, if I set
>>>>
>>>> # kernel provider
>>>> PREFERRED_PROVIDER_virtual/kernel = "linux-omap3"
>>>>
>>>> and try to build my machine, I get the following errors:
>>>>
>>>> ERROR: Function failed: Fetcher failure for URL: 'file://defconfig'. Unable to fetch URL from any source.
>>>> NOTE: package linux-omap3-3.2-r0: task do_fetch: Failed
>>>> ERROR: Task 125 (/tool/yocto/meta-gumstix/recipes-kernel/linux/linux-omap3_3.2.bb, do_fetch) failed with exit code '1'
>>>> NOTE: Tasks Summary: Attempted 304 tasks of which 302 didn't need to be rerun and 1 failed.
>>>>
>>>> Summary: 1 task failed:
>>>>   /tool/yocto/meta-gumstix/recipes-kernel/linux/linux-omap3_3.2.bb, do_fetch
>>>
>>> I solved this one.
>>>
>>> Turns out, since I defined a new machine called overo-fire-chestnut43, I had to also create a folder called overo-fire-chestnut43 to hold the defconfig file as follows:
>>>
>>> meta-gumstix/recipes-kernel/linux/linux-omap3/overo-fire-chestnut43/defconfig
>>>
>>> I recall, the trend was to move away from user supplied defconfigs, and have it get generated automatically by the build process, and then specify some hints. Is there any example of how I can modify the existing meta-gumstix or any other meta-layer, to get the defconfig to get generated automatically?
>>
>> Are you thinking about the linux-yocto config fragment support ?
>> Or maybe something else ? If you were thinking about the fragments,
>> it would only replace your defconfigs directly when you use a linux-yocto
>> kernel tree (and it's included meta branch with configuration frags).
>> In that scenario, you only put your board specific fragments on the end,
>> and let the rest be constructed.
>>
>> When I return home next week, I will have some patches for 1.3 that make
>> the fragments apply more easily to any git repository, but in either
>> case (1.2 or 1.3), you'd still need to build up a series of fragments
>> outside the tree, or migrate to linux-yocto* for maxium re-use.
>
> Bruce,
>
> I'd be willing to start using config fragments for our kernels in meta-ti,
> when this feature is not tightly bundled with linux-yocto kernel. While we
> might want to eventually start using the entire linux-yocto framework for our
> kernels, it may take longer time due to many internal constraints. And having
> config fragments available as a separate feature would be very helpful and
> enable us to take baby steps... :) That's what we discussed last month at the
> Yocto BSP Summit. Thanks.

Absolutely. It's available in my dev trees, but I ended up in Sweden this
week,
so I'm time shifted and time constrained, so I held of sending the
pull request. When I'm back to the office in next week, I'll be sending
out my queued changes along with some instructions.

I expect that they won't work perfectly for everyone, so I'll be tweaking
and changing as required. (hence why I wanted to be around).

Thanks for the interest, I look forward to seeing more fragments and fewer
full configs. (I'm off my soapbox now:)

Cheers,

Bruce

>