From mboxrd@z Thu Jan 1 00:00:00 1970 From: Darren Hart Subject: Re: [RFC PATCH v2 01/16] ACPI: Add support for device specific properties Date: Mon, 06 Oct 2014 09:25:35 -0700 Message-ID: References: <1410868367-11056-1-git-send-email-mika.westerberg@linux.intel.com> <1410868367-11056-2-git-send-email-mika.westerberg@linux.intel.com> <20141006135021.0EB04C43FBE@trevor.secretlab.ca> <20141006143248.GE1583@lahna.fi.intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20141006143248.GE1583@lahna.fi.intel.com> Sender: linux-acpi-owner@vger.kernel.org To: Mika Westerberg , Grant Likely Cc: "Rafael J. Wysocki" , linux-acpi@vger.kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, Greg Kroah-Hartman , Linus Walleij , Alexandre Courbot , Dmitry Torokhov , Bryan Wu , Lee Jones , Arnd Bergmann , Aaron Lu List-Id: devicetree@vger.kernel.org On 10/6/14, 7:32, "Mika Westerberg" wrote: >On Mon, Oct 06, 2014 at 02:50:21PM +0100, Grant Likely wrote: >> >> > +/* ACPI _DSD device properties UUID: >>daffd814-6eba-4d8c-8a91-bc9bbf4aa301 */ >> > +static const u8 prp_uuid[16] = { >> > + 0x14, 0xd8, 0xff, 0xda, 0xba, 0x6e, 0x8c, 0x4d, >> > + 0x8a, 0x91, 0xbc, 0x9b, 0xbf, 0x4a, 0xa3, 0x01 >> > +}; >> >> ? >> >> What is the encoding used here? I see the first 4 bytes for "daffd814" >> encoded in little endian (0x14 first), and then the remaining values >> encoded in big-endian for each number. Is this typical for UUID values? > >The buffer format is explained in ACPI 5.1 spec, page 823. > >I generated the above so that I compiled a _DSD with correct UUID using >iASL and then disassambled it with the same tool. > I bugged Mika with the same question, it's a fairly non-intuitive encoding :-) -- Darren Hart Intel Open Source Technology Center