On 02/01/17 16:16, Igor Mammedov wrote: > On Wed, 1 Feb 2017 14:03:52 +0100 > Laszlo Ersek <ler...@redhat.com> 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" <m...@redhat.com> 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
