Re: Wayland and X11 on Yocto


Manuel Wagesreither
 

Hi all, hi Khem,

Am Do, 19. Aug 2021, um 00:22, schrieb Khem Raj:
On Wed, Aug 18, 2021 at 3:06 PM Manuel Wagesreither <ManWag@fastmail.fm> wrote:

Hello all,

I'm building an image to run on various SBCs and would like to equip it with a graphical interface.

There are quite a few things very unclear to me. Can someone help me with that?

* Why is X11 enabled by setting an IMAGE_FEATURE (namely x11, x11-base or x11-sato), while Wayland is enabled by IMAGE_INSTALL only (weston-init and weston)?
x11-* features is primarily to control what kind of x11 packages you
want to include in image e.g.
./meta/recipes-sato/packagegroups/packagegroup-core-x11-sato.bb is
pulled in when x11-sato is added to IMAGE_FEATURES
we have many X11 based images and sato is one of them so thats why its
separated out.
Okay, so if I get things right then IMAGE_FEATURES+="x11" is under the hood nothing more than an IMAGE_INSTALL+="packagegroup-core-x11". Is that right? If so, what's the purpose of adding the concept of IMAGE_FEATURE? I mean, it doesn't make things SO much easier. Setting an IMAGE_FEATURE or an IMAGE_INSTALL variable is the same to me.

you should really is looking at DISTRO_FEATURES e.g. wayland distro
feature is needed for core-image-weston to build.
Yepp, I know. I left them out on purpose because I was mainly interested in where the configuration for X11 and wayland differs conceptually. With "conceptually" I mean that one is added through IMAGE_FEATURES while the other is through IMAGE_INSTALL.

* Theory: Is IMAGE_FEATURE +=x11 manipulating IMAGE_INSTALL under the hood so you don't have to do it manually? And as there is no IMAGE_FEATURE "wayland", you have do it manually. Correct?
* Why is Wayland different in that it doesn't need an IMAGE_FEATURE to enable it?
there are not many wayland based compositors or images we have in core
as of now.
And if there would be more wayland based compositors or images then you would turn extract this into an IMAGE_FEATURE as well? Why? How does that make things easier? Again, I feel there's something to IMAGE_FEATURES I didn't yet understand.

* Why does core-image-weston.bb need to enable IMAGE_FEATURE hwcodec, while core-image-x11.bb does not? (Dunfell branch.)
openGL is needed for wayland/weston to work too but hwcodec feature is
infact to pull in machine specific drivers MACHINE_HWCODECS into image
if a given BSP defined it.
e.g. intel bsps define vaapi codecs and mediasdk for specific machines
via MACHINE_HWCODECS
defaults for this image features are empty
Thanks for the explanation on MACHINE_HWCODEC. I'm curious, so is core-image-x11 require DISTRO_FEATURE hwcodec or not? If yes, than it seems to be missing in the core-image-x11.bb (it's in the core-images-weston.bb, after all), if no, then why is it not required for X11?


I know I'm asking quite detailed questions, but I got the feeling I need to understand this once and for all.

Thanks, regards, Manuel

Join yocto@lists.yoctoproject.org to automatically receive all group messages.