On 04/02/19 17:52, Laszlo Ersek wrote: > On 04/02/19 17:42, Auger Eric wrote:
>>>>> The firmware does consume DT: >>>>> >>>>> - If you start QEMU *with* "-no-acpi", then the DT is both consumed by >>>>> the firmware (for its own information needs), and passed on to the OS. >>>>> >>>>> - If you start QEMU *without* "-no-acpi" (the default), then the DT is >>>>> consumed only by the firmware (for its own information needs), and the >>>>> DT is hidden from the OS. The OS gets only the ACPI content >>>>> (processed/prepared as described above). > >> I am confused by the above statement actually. In the above case what >> does happen if you pass the acpi=off in the kernel boot parameters? > > If you launch QEMU with "-no-acpi" and you pass "acpi=off" to the guest > kernel, then the kernel will not boot successfully, as it will not get > DT from the firmware, and it will ignore the ACPI tables that it does > get from the firmware. Sorry, I ended up answering "what happens when you run QEMU *without* -no-acpi and pass acpi=off to the guest kernel". To explain what happens when you boot *with* -no-acpi: in that case, "acpi=off" doesn't matter, since the guest kernel doesn't get ACPI tables anyway. The kernel will go for DT. Thanks Laszlo
