Yocto: why is a package included?

Question

I am currently using yocto for building an embedded linux image for TI AM335x (I am using hob, since I find it more comfortable than using command-line).

I start using the recipe for building 'core-image-base' and here is the selection of packages which are included:

Now I would like to exclude the package alsa-utils-1.0.28-r0 from build, since it has some problems compiling for my target and I really do not need it... so, as far as I can understand, I have to remove all the dependencies which brought alsa-utils in (that is: alsa-state and packagegroup-base, looking at following screenshot):

So I move to Package groups tab and I remove packagegroup-base and then I remove alsa-state and alsa-utils from the Included recipes:

Now it seems that alsa-utils is there no more... but if I try to build the image, this is the result:

Why? Who is still bringing-in alsa-utils? What am I doing wrong? Is there a way (even command-line) to know why a package is brought-in by yocto?

Answer 1

Use

bitbake -g alsa-utils -u depexp

to display a dependency tree you should be able to see who's depending on it.

See the openembedded wiki.

Answer 2

There is now a proper tool in Yocto to identify why a package is built.

You must first generate the dependency graph for the final recipe you want to build. Then, run oe-depends-dot --why:

 $ bitbake -g core-image-minimal
 $ oe-depends-dot -k busybox -w ./task-depends.dot
Because: core-image-minimal packagegroup-core-boot
core-image-minimal -> packagegroup-core-boot -> busybox