ACPI

The driver

drivers/acpi/driver_acpi.c - RSDP discovery (multiboot2 tags 14/15 on EFI, memory scan on BIOS), RSDT/XSDT, FADT, DSDT, MCFG. driver_acpi_aml.c - a real AML namespace walker (the acpidev command lists the namespace it finds). driver_acpi_power.c + arch_acpi_s3*.S - S3 suspend/resume.

What ACPI feeds

• Power control (FADT PM1a_CNT): acpipow, shutdown/reboot paths.
• The WDAT watchdog table (E2E-verified arming + real reset).
• GPE/SCI events.
• The S3 suspend path (suspend/suspend_test commands; the resume path returns through the assembly trampoline).

Commands

oc> acpi        (table dump: RSDP/FADT/DSDT/MCFG)
oc> acpidev     (AML namespace devices)
oc> acpitest    (parser self-test)
oc> acpipow     (power control status)

Bring-up notes

• q35 vs i440fx differ in table layouts - both parse.
• The AML walker is defensive: malformed tables stop the walk with a message, not a fault.