[poky] workflow - kernel config

[Bruce Ashfield]

On Fri, Nov 4, 2011 at 1:23 PM, Robert Berger
<gmane at reliableembeddedsystems.com> wrote:
> Hi,
>
> I'm playing with poky-edison-6.0 and the default 2.6.37.6 kernel on a
> beagle board with core-image-sato-sdk.
>
> Interestingly enough there is user space support e.g. for oprofile, but
> oprofile is not configured in the kernel.
>
> The same for lacencytop and powertop,...

We have feature descriptions for all of the above as components in the
linux-yocto
kernel repository, but they do need to be turned on and tested on a per board
basis.

We can trigger kernel options based on userspace packages being enabled or
disabled, but that still wouldn't be a guarantee that they'd work. The
options that
are within the tree are a documentation of what has actually been tested.

The 2.6.37 tree was a transition point,and we've continued standardizing the
options and feature set in the later kernels. For yocto 1.2 we'll have a better
defined and consistent set of feature blocks. It's a building process
and we move
forward.

As others will point out there are other/deeper beagle board BSPs and layers
(i.e. meta-texasinstruments) that likely already have support for these options\
(but I haven't checked recently), so that's an avenue to explore as well.

>
> So I was wondering what's the preferred workflow to start with the
> "yocto-default" kernel config and add kernel configuration options
> afterwards.
>
> What's I've tried so far is:
>
> bitbake virtual/kernel -c clean
> bitbake virtual/kernel -c configure
> bitbake virtual/kernel -c menuconfig
> bitbake virtual/kernel -c compile
> bitbake virtual/kernel -c deploy

This is one flow that will work to make changes to the default kernel, and
test them on a board. I use something like:

 bitbake -f -c configure linux-yocto
 bitbake -f -c menuconfig
 bitbake -c linux-yocto

after I've done an initial build/configure phase if I'm updating options.
But that's likely not the most efficient workflow either (I've got liberal
use of -f in there, since I'm a bit paranoid).

>
> Once I'll have a kernel config I'm happy with I would like to use a
> config file instead of menuconfig.

If you take the set of kernel options you are interested in, and put them
in a config fragment. i.e. my_options.cfg, you can simply add this to
the SRC_URI and those options will be applied to the kernel after all the
default ones have been applied.

Hope that helps a bit.

Bruce

>
> Please advise,
>
> Regards,
>
> Robert
> ...WANTED: Schroedinger's Cat. Dead or Alive.
>
> My public pgp key is available at:
> http://pgp.mit.edu:11371/pks/lookup?op=get&search=0x90320BF1
>
>
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