[OE-core] RFC: Using formfactor data in other recipes

[Richard Purdie]

On Wed, 2013-10-16 at 14:50 +0100, Paul Eggleton wrote:
> Hi all,
> 
> Andrea has been doing some cleanup on meta-handheld, and he and I have come 
> across what seems to be a bit of a shortcoming with formfactor over the 
> variable-based alternative that was used in OE-Classic (MACHINE_GUI_CLASS, 
> MACHINE_DISPLAY_WIDTH_PIXELS, MACHINE_DISPLAY_HEIGHT_PIXELS etc.). In 
> meta-opie, the latter variables are still being used in a machine-specific 
> packagegroup recipe to select the appropriate set of pixmaps to be installed 
> for each machine based on the screen resolution, so you don't have to have 
> pixmaps installed that you're never going to use (which would waste storage 
> space).
> 
> formfactor is the current method supported in OE-Core for representing 
> differences in machine display/input characteristics, however it seems only 
> queryable at runtime since its files are not written into the sysroot. We could 
> change it to stage to the sysroot, and therefore the data could be queried at 
> least at packaging time in other recipes that depend on formfactor. Does this 
> sound like a reasonable solution for this kind of problem, or is there a 
> better solution?

Seems reasonable. We tend not to install some things to the sysroot as
they're pointless (e.g. man pages or a lot of etc data) but in this case
it would make sense to override the defaults as its information we can
use.

Cheers,

Richard