Old operating systems would like to have a rev1 (ACPI 1.0) FADT, but new operating systems would like to have rev3 (ACPI 2.0). Since old operating systems do not know about XSDTs, the solution is to point the RSDT to a v1 FADT and the XSDT to a rev3 FADT.
Paolo Bonzini (2): seabios: build RSDT from XSDT seabios: create rev1 FADT in compatibility RSDT src/fw/paravirt.c | 68 ++++++++++++++++++++++++++++++++++++++++++++++++++++++- src/std/acpi.h | 11 +++++++++ 2 files changed, 78 insertions(+), 1 deletion(-) -- 2.13.3
