Shipping Multiple Devicetrees: How to Identify Which DTB Is for My Board?
summary
Qualifies the problem with numbers and a concrete proposal: Qualcomm ships 20 DTBs and over 100 overlays so a single image must pick the right DTB; current approaches (long compatible strings, bootloader-specific parsing, or huge DT overlays) get brittle. Proposal adds a board-id property in root node containing vendor magic numbers that bootloaders (U-Boot, coreboot, FIT) can read and match against hardware IDs so the bootloader selects the DTB without custom string parsing.
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chapters (7)
- 0:00Multiple device trees intro
- 2:46Shipping multiple device trees
- 10:53Device tree selection challenges
- 18:35Unified board ID proposal
- 27:47Board ID implementation discussion
- 42:04Backward compatibility & future
- 49:20Q&A
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