Record the firmware-neutrality contract as decision 7

Discovery is one swappable process per firmware (acpi service on x86, an
fdt service on the Pis); everything at and above the device-manager
protocol stays generic. The manager owns the tree as data and never
touches hardware — firmware bytecode runs in a crashable, supervised
discoverer. Flagged now: hid[8] cannot hold an FDT compatible string,
and cross-firmware protocols are named by domain (power, not ACPI).
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Daniel Samson 2026-07-13 01:33:12 +01:00
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@ -57,6 +57,21 @@ branch is green; keep branches; push everything.
6. **Both new processes are protocol drivers** under the manager: hello,
supervision, restart with backoff — all inherited from M18.1 for free.
Registration idempotence (decision 3) is what makes their restarts sound.
7. **Firmware neutrality is the contract** (2026-07-13). The generic layer is
everything at and above the device-manager protocol — descriptors,
containment, reports, matching, supervision — and none of it may become
x86-specific. Discovery is one swappable process per firmware: the acpi
service on x86; an **fdt service** on the Raspberry Pis (claims a
`devicetree-blob` node, reports children from the flattened device tree —
pure data, no bytecode, no port grant, strictly simpler than ACPI). The
manager owns the tree as *data* and touches no hardware, ever — AML runs in
a crashable, supervised discoverer precisely so a firmware-bytecode fault
can never take down the supervisor. Two consequences recorded now:
`DeviceDescriptor`'s 8-byte `hid` cannot hold an FDT `compatible` string
("brcm,bcm2835-aux-uart") — identity widens before the fdt service exists;
and cross-firmware surfaces are named by **domain, not firmware** (M21
defines a *power* protocol, not an "ACPI events" protocol — PSCI/mailbox
sources feed the same subscribers on ARM).
## Status