Speakers
Description
SBCs like the Arduino UNO Q can have a number of extension boards, like the UNO Media Carrier or an Arduino shield connected. On top of this extra hardware may be connected through e.g. CSI camera connectors and DSI display connectors.
Each of these possible hardware addons needs a DT overlay to work. This requires some method for the user to select which DT overlays to use.
There have been several attempts a decade ago to allow loading DT overlays from Linux userspace for this, but non has ever been accepted upstream.
UKI addons can provide an updated DTB, the purpose of this session is to present and discuss a proposal to use this to manage DT overlays from userspace through UKI addons:
Phase 1: UKI addons with a replacement DTB file embedded
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For systems booting with secureboot, create DTBs with overlays merged in for popular hardware addon combinations and build a signed UKI addon for each such DTB on the distros build-system.
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For systems without secureboot any overlay combination can be supported by building a merged DTB locally and creating an UKI addon from that DTB.
Phase 2: UKI addons with a DTBO file embedded
- For this phase the UKI stub needs to be extended with the capability to merge DTBOs from addons into an earlier loaded DTB, allowing any combination of overlays by the distro providing a signed UKI addon for each available overlay.