From mboxrd@z Thu Jan 1 00:00:00 1970 From: mark.rutland@arm.com (Mark Rutland) Date: Mon, 4 Jan 2016 15:14:09 +0000 Subject: [Xen-devel] [PATCH v3 20/62] arm/acpi: Add ACPI support for SMP initialization In-Reply-To: <20160104150044.GC7050@leverpostej> References: <1447753261-7552-1-git-send-email-shannon.zhao@linaro.org> <1447753261-7552-21-git-send-email-shannon.zhao@linaro.org> <565C63F1.5070303@citrix.com> <56834B4C.40409@huawei.com> <20160104150044.GC7050@leverpostej> Message-ID: <20160104151409.GE7050@leverpostej> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org 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: > > On Wed, 30 Dec 2015, Shannon Zhao wrote: > > > 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.