On Mon, Jan 04, 2016 at 03:00:45PM +0000, Mark Rutland wrote:

On Mon, Jan 04, 2016 at 02:51:51PM +0000, Stefano Stabellini wrote:

quoted

On Wed, 30 Dec 2015, Shannon Zhao wrote:

quoted

I check this again. There are not limitations of supporting PSCI version
in ACPI SPEC. It should support PSCI 0.1 as well. But look at the code
of linux kernel, it says it only supports PSCI 0.2+.

#define ACPI_FADT_PSCI_COMPLIANT    (1)	/* 00: [V5+] PSCI 0.2+ is
implemented */

So does it need to be consistent with Linux or support PSCI 0.1 in Xen
as well?

I don't think it needs to be consistent with Linux. I would support PSCI
0.1 too.

That's not possible, so I don't follow. Prior to 0.2 the function IDs
are not defined.

The FADT has a single bit which describes PSCI 0.2+ being implemented,
and does not describe function IDs.

I've now spotted that this wording is indeed missing from the ACPI
documentation. I believe this is a documentation bug, as the intent was
always for the bit to imply PSCI 0.2+.

Mark.