From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:53269) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1cYxNu-0006L8-FX for qemu-devel@nongnu.org; Wed, 01 Feb 2017 11:03:51 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1cYxNr-0006yr-BY for qemu-devel@nongnu.org; Wed, 01 Feb 2017 11:03:50 -0500 Received: from mx1.redhat.com ([209.132.183.28]:39068) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1cYxNr-0006yk-3m for qemu-devel@nongnu.org; Wed, 01 Feb 2017 11:03:47 -0500 References: <1484739954-86833-1-git-send-email-phil@philjordan.eu> <20170118175335-mutt-send-email-mst@kernel.org> <20170118181918.783cb7bd@nial.brq.redhat.com> <20170131165802-mutt-send-email-mst@kernel.org> <20170131201333-mutt-send-email-mst@kernel.org> <20170201123739.387de47b@nial.brq.redhat.com> <6e912456-9d9c-7084-c4b4-91596216d3dd@redhat.com> <20170201161636.28f1e2dc@nial.brq.redhat.com> From: Laszlo Ersek Message-ID: <7c950267-9cd6-2e85-8b5e-218c0c7f7bdb@redhat.com> Date: Wed, 1 Feb 2017 17:03:38 +0100 MIME-Version: 1.0 In-Reply-To: <20170201161636.28f1e2dc@nial.brq.redhat.com> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH RFC] acpi: add reset register to fadt List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Igor Mammedov Cc: "Michael S. Tsirkin" , Paolo Bonzini , Phil Dennis-Jordan , Richard Henderson , Eduardo Habkost , qemu-devel@nongnu.org On 02/01/17 16:16, Igor Mammedov wrote: > On Wed, 1 Feb 2017 14:03:52 +0100 > Laszlo Ersek wrote: > >> On 02/01/17 13:52, Laszlo Ersek wrote: >>> On 02/01/17 12:37, Igor Mammedov wrote: >>>> On Tue, 31 Jan 2017 20:17:02 +0200 >>>> "Michael S. Tsirkin" wrote: >>>> >>>>> On Tue, Jan 31, 2017 at 05:28:57PM +0100, Laszlo Ersek wrote: >>>>>> The ACPI 6.1 spec says, >>>>>> >>>>>> - DSDT: [...] If the X_DSDT field contains a non-zero value then this >>>>>> field must be zero. >>>>>> - X_DSDT: [...] If the DSDT field contains a non-zero value then this >>>>>> field must be zero. >>>>> >>>>> But that's only 6.1. 6.0 and earlier did not say this. >>>>> The errata they wanted to address was: >>>>> 1393 In FADT: if X_DSDT field is non-zero, DSDT >>>>> field should be ignored or deprecated >>>>> >>>>> I would class this as a spec bug. >>>>> >>>> >>>> The same applies to X_PM1a_EVT_BLK and co, >>>> for example 5.1 spec "This is a required >>>> field." >>>> >>>> And looks like Windows implemented it as mandatory >>>> to boot perhaps to be compatible with 5.1 and earlier >>>> specs. >>>> >>>> It appears fw would be forced to fill fields depending >>>> on table revision. >>> >>> Sounds like a valid point. >>> >>> I compared the FADT defintion between ACPI 5.1 and ACPI 6.1. Indeed, the >>> former says: >>> >>> - FADT Major Version: 5; Major Version of this FADT structure, [...] >>> - DSDT: Physical memory address (0-4 GB) of the DSDT. >>> - X_DSDT: 64bit physical address of the DSDT. >>> >>> the latter says: >>> >>> - FADT Major Version: 6; Major Version of this FADT structure, [...] >>> >>> - DSDT: Physical memory address of the DSDT. If the X_DSDT field >>> contains a non-zero value then this field must be zero. >>> >>> - X_DSDT: Extended physical address of the DSDT. If the DSDT field >>> contains a non-zero value then this field must be zero. >>> >>> I will ask on edk2-devel whether the >>> "MdeModulePkg/Universal/Acpi/AcpiTableDxe" maintainers can think of a >>> way to accommodate this. >> >> Sigh, this looks nasty. >> >> Considering specifically the DSDT <-> X_DSDT question, Mantis ticket >> #1393 (which requires the mutual exclusion) went into 5.1B. In version >> 5.1A, the mutual exclusion is not required. >> >> Unfortuantely, the FADT Major.Minor version, as reported through the >> bytes at offsets 8 and 131 decimal in the table, is "5.1" for *both* >> 5.1A and 5.1B. In other words, looking at just Major.Minor, it cannot be >> determined with full precision whether the DSDT and X_DSDT fields should >> be exclusive or not. :/ > The same applies to 6.0 vs 6.0A Thanks for the info; I've updated the patch! Laszlo