Unifying cape overlays into boot .dtb for BeagleBoard.org boards

[Jason Kridner]

On Tue, Jun 17, 2014 at 12:01 PM, Russell King - ARM Linux
<linux at arm.linux.org.uk> wrote:
> On Tue, Jun 17, 2014 at 04:32:11PM +0300, Pantelis Antoniou wrote:
>> The complexity is absolutely required, and it has nothing to do with
>> beaglebone capes.
>>
>> The fact of the matter is that reconfigurable hardware is here, on
>> shipping system, and we, as the linux kernel community have to make
>> sure it works, and that it works in a sane way.
>
> Right, so looking back in the git history, this project has been going
> on for... at least four years?  Probably longer than the length of time
> that we've been converting ARM to DT.  At no point during that has anyone
> brought up the issue of DT being dynamic, so none of the drivers which
> we have been converting caters for this.
>
> Isn't this a bit of a missed opportunity, if this is a direction that
> OF wishes to head towards?

I believe it absolutely is a missed opportunity, but that doesn't mean
it isn't still needed moving forward. We've been using overlays
successfully in the BeagleBoard.org community on BeagleBone Black for
over a year now. It is just a shame we're still shipping a 3.8 kernel.
This universal overlay provides hope to support most add-ons, but it
doesn't address the dynamic nature of some add-on hardware. It is
certainly my hope that this effort doesn't derail the overlay
development work.

>
> Wouldn't it have been relevant to the discussion at kernel summit too,
> concerning DRM/v4l2/componentised systems?  What if someone comes along
> tomorrow with part of their multimedia based system inside a FPGA
> which they program up at runtime?
>
> --
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> improving, and getting towards what was expected from it.