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ACPI Table updates during resuming from hibernate RRS feed

  • Question

  • Hi,

    We have a UEFI driver that creates an ACPI table with some vendor information whenever it gets executed and this is read using a non-boot Kernel mode driver on Windows. This works fine with cold boot.

    Now with hibernate and resume cycle, if this ACPI table is updated during resume, we see inconsistent behavior on Win7, some times we read an updated ACPI table and some-times old ACPI table (we think OS has restored during resume).

    On WIN 8, we see OS restoring ACPI tables on resume (hibernate/shutdown with hybrid boot). So we always read old data.Also observed that If a new Table is created during resume from S4, it is not reflected in OS.

      • Is there a way to read always new ACPI table data during resume from S4? 
      • Is creating/deleting/updating of ACPI tables allowed during resume from S4 (assuming memory map published doesn't change)?

    Thanks,

    Vikranth

    Monday, October 8, 2012 5:17 AM

Answers

  • from the ACPI folks in windows

    All static tables (those defined through the XSDT or the RSDT in ACPI) are read only at boot time.  Any information which might be changed across a sleep/hibernate cycle must be in the dynamic part of ACPI, the DSDT or an SSDT.


    d -- This posting is provided "AS IS" with no warranties, and confers no rights.

    Monday, October 8, 2012 8:30 PM

All replies

  • from the ACPI folks in windows

    All static tables (those defined through the XSDT or the RSDT in ACPI) are read only at boot time.  Any information which might be changed across a sleep/hibernate cycle must be in the dynamic part of ACPI, the DSDT or an SSDT.


    d -- This posting is provided "AS IS" with no warranties, and confers no rights.

    Monday, October 8, 2012 8:30 PM
  • Hi Doron,

    Could you please let me know if it is possible to access the RSDP or other ACPI tables in kernel mode. I am aware of the GetSystemFirmwareTable API, but that doesnt work in kernel mode.

    I need this to access the Extended PCI config space (MCFG table).

    Wednesday, October 31, 2012 5:54 PM
  • Hi ShashiNV... I have the same problem... I found AuxKlibGetSystemFirmwareTable routine. Did you try?... wondering if you get success ... any advise is really appreciatted..

    thanks.

    Tuesday, May 7, 2013 7:30 PM