[PATCH v2] EmbeddedPkg: add DT platform driver to select between DT and ACPI

[Ard Biesheuvel <ard.biesheuvel@linaro.org>]

As a follow up to the changes proposed by Laszlo to make ACPI and DT
mutually exclusive on ArmVirtQemu, this patch proposed a DT platform
DXE driver that either installs the NULL protocol PlatformHasAcpiGuid,
or installs the FV embedded DTB binary as a configuration table under
the appropriate GUID, depending on a preference setting recorded as
a UEFI variable, and configurable via a HII screen.

The DTB binary can be embedded in the firmware image by adding the
following to the platform .fdf file:

  FILE FREEFORM = 25462CDA-221F-47DF-AC1D-259CFAA4E326 {
    SECTION RAW = SomePkg/path/to/foo.dtb
  }

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
---
v2: fixup various errors and rough edges pointed out by Laszlo

 EmbeddedPkg/EmbeddedPkg.dec                         |   6 +
 EmbeddedPkg/Drivers/DtPlatformDxe/DtPlatformDxe.inf |  65 ++++++
 EmbeddedPkg/Drivers/DtPlatformDxe/DtPlatformDxe.h   |  31 +++
 EmbeddedPkg/Include/Guid/DtPlatformDefaultDtbFile.h |  23 +++
 EmbeddedPkg/Include/Guid/DtPlatformFormSet.h        |  23 +++
 EmbeddedPkg/Drivers/DtPlatformDxe/DtPlatformHii.vfr |  51 +++++
 EmbeddedPkg/Drivers/DtPlatformDxe/DtPlatformDxe.c   | 216 ++++++++++++++++++++
 EmbeddedPkg/Drivers/DtPlatformDxe/DtPlatformHii.uni |  27 +++
 8 files changed, 442 insertions(+)

diff --git a/EmbeddedPkg/EmbeddedPkg.dec b/EmbeddedPkg/EmbeddedPkg.dec
index 29736fb4a71d..871fc5ff4016 100644
--- a/EmbeddedPkg/EmbeddedPkg.dec
+++ b/EmbeddedPkg/EmbeddedPkg.dec
@@ -62,6 +62,12 @@ [Guids.common]
   ## Include/Guid/PlatformHasDeviceTree.h
   gEdkiiPlatformHasDeviceTreeGuid = { 0x7ebb920d, 0x1aaf, 0x46d9, { 0xb2, 0xaf, 0x54, 0x1e, 0x1d, 0xce, 0x14, 0x8b } }
 
+  # HII form set GUID for DtPlatformDxe driver
+  gDtPlatformFormSetGuid = { 0x2b7a240d, 0xd5ad, 0x4fd6, { 0xbe, 0x1c, 0xdf, 0xa4, 0x41, 0x5f, 0x55, 0x26 } }
+
+  # File GUID for default DTB image embedded in the firmware volume
+  gDtPlatformDefaultDtbFileGuid = { 0x25462cda, 0x221f, 0x47df, { 0xac, 0x1d, 0x25, 0x9c, 0xfa, 0xa4, 0xe3, 0x26 } }
+
 [Protocols.common]
   gHardwareInterruptProtocolGuid =  { 0x2890B3EA, 0x053D, 0x1643, { 0xAD, 0x0C, 0xD6, 0x48, 0x08, 0xDA, 0x3F, 0xF1 } }
   gEfiDebugSupportPeriodicCallbackProtocolGuid = { 0x9546e07c, 0x2cbb, 0x4c88, { 0x98, 0x6c, 0xcd, 0x34, 0x10, 0x86, 0xf0, 0x44 } }
diff --git a/EmbeddedPkg/Drivers/DtPlatformDxe/DtPlatformDxe.inf b/EmbeddedPkg/Drivers/DtPlatformDxe/DtPlatformDxe.inf
new file mode 100644
index 000000000000..aa1d3abb4012
--- /dev/null
+++ b/EmbeddedPkg/Drivers/DtPlatformDxe/DtPlatformDxe.inf
@@ -0,0 +1,65 @@
+## @file
+#
+#  Copyright (c) 2017, Linaro, Ltd. All rights reserved.<BR>
+#
+#  This program and the accompanying materials are licensed and made
+#  available under the terms and conditions of the BSD License which
+#  accompanies this distribution.  The full text of the license may be
+#  found at http://opensource.org/licenses/bsd-license.php
+#
+#  THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
+#  WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR
+#  IMPLIED.
+#
+##
+
+[Defines]
+  INF_VERSION               = 0x00010019
+  BASE_NAME                 = DtPlatformDxe
+  FILE_GUID                 = FC097B3C-2EBD-4A75-A3DA-121DCAB365CC
+  MODULE_TYPE               = DXE_DRIVER
+  VERSION_STRING            = 1.0
+  ENTRY_POINT               = DtPlatformDxeEntryPoint
+
+#
+# The following information is for reference only and not required by the build tools.
+#
+#  VALID_ARCHITECTURES      = IA32 X64 ARM AARCH64
+#
+
+[Sources]
+  DtPlatformDxe.c
+  DtPlatformHii.vfr
+  DtPlatformHii.uni
+
+[Packages]
+  EmbeddedPkg/EmbeddedPkg.dec
+  MdePkg/MdePkg.dec
+  MdeModulePkg/MdeModulePkg.dec
+
+[LibraryClasses]
+  BaseLib
+  DebugLib
+  UefiLib
+  UefiDriverEntryPoint
+  UefiBootServicesTableLib
+  UefiRuntimeServicesTableLib
+  UefiHiiServicesLib
+  MemoryAllocationLib
+  HiiLib
+  PcdLib
+  DxeServicesLib
+
+[Guids]
+  gDtPlatformFormSetGuid
+  gEdkiiPlatformHasAcpiGuid
+  gDtPlatformDefaultDtbFileGuid
+  gFdtTableGuid
+
+[Protocols]
+  gEfiHiiConfigAccessProtocolGuid                ## PRODUCES
+
+[Depex]
+  gEfiHiiDatabaseProtocolGuid         AND
+  gEfiVariableArchProtocolGuid        AND
+  gEfiVariableWriteArchProtocolGuid
diff --git a/EmbeddedPkg/Drivers/DtPlatformDxe/DtPlatformDxe.h b/EmbeddedPkg/Drivers/DtPlatformDxe/DtPlatformDxe.h
new file mode 100644
index 000000000000..2369367277b0
--- /dev/null
+++ b/EmbeddedPkg/Drivers/DtPlatformDxe/DtPlatformDxe.h
@@ -0,0 +1,31 @@
+/** @file
+*
+*  Copyright (c) 2017, Linaro Limited. All rights reserved.
+*
+*  This program and the accompanying materials
+*  are licensed and made available under the terms and conditions of the BSD License
+*  which accompanies this distribution.  The full text of the license may be found at
+*  http://opensource.org/licenses/bsd-license.php
+*
+*  THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
+*  WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
+*
+**/
+
+#ifndef __DT_PLATFORM_DXE_H__
+#define __DT_PLATFORM_DXE_H__
+
+#include <Guid/HiiPlatformSetupFormset.h>
+#include <Guid/DtPlatformFormSet.h>
+
+#define DT_ACPI_SELECT_DT       0x0
+#define DT_ACPI_SELECT_ACPI     0x1
+
+#define DT_ACPI_VARIABLE_NAME   L"DtAcpiPref"
+
+typedef struct {
+  UINT8         Pref;
+  UINT8         Reserved[3];
+} DT_ACPI_VARSTORE_DATA;
+
+#endif
diff --git a/EmbeddedPkg/Include/Guid/DtPlatformDefaultDtbFile.h b/EmbeddedPkg/Include/Guid/DtPlatformDefaultDtbFile.h
new file mode 100644
index 000000000000..c44b4d9522fe
--- /dev/null
+++ b/EmbeddedPkg/Include/Guid/DtPlatformDefaultDtbFile.h
@@ -0,0 +1,23 @@
+/** @file
+*
+*  Copyright (c) 2017, Linaro Limited. All rights reserved.
+*
+*  This program and the accompanying materials
+*  are licensed and made available under the terms and conditions of the BSD License
+*  which accompanies this distribution.  The full text of the license may be found at
+*  http://opensource.org/licenses/bsd-license.php
+*
+*  THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
+*  WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
+*
+**/
+
+#ifndef __DT_PLATFORM_DEFAULT_DTB_FILE_H__
+#define __DT_PLATFORM_DEFAULT_DTB_FILE_H__
+
+#define DT_PLATFORM_DEFAULT_DTB_FILE_GUID  \
+  { 0x25462cda, 0x221f, 0x47df, { 0xac, 0x1d, 0x25, 0x9c, 0xfa, 0xa4, 0xe3, 0x26 } }
+
+extern EFI_GUID gDtPlatformDefaultDtbFileGuid;
+
+#endif
diff --git a/EmbeddedPkg/Include/Guid/DtPlatformFormSet.h b/EmbeddedPkg/Include/Guid/DtPlatformFormSet.h
new file mode 100644
index 000000000000..71e3e7ebf7f3
--- /dev/null
+++ b/EmbeddedPkg/Include/Guid/DtPlatformFormSet.h
@@ -0,0 +1,23 @@
+/** @file
+*
+*  Copyright (c) 2017, Linaro Limited. All rights reserved.
+*
+*  This program and the accompanying materials
+*  are licensed and made available under the terms and conditions of the BSD License
+*  which accompanies this distribution.  The full text of the license may be found at
+*  http://opensource.org/licenses/bsd-license.php
+*
+*  THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
+*  WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
+*
+**/
+
+#ifndef __DT_PLATFORM_FORMSET_H__
+#define __DT_PLATFORM_FORMSET_H__
+
+#define DT_PLATFORM_FORMSET_GUID  \
+  { 0x2b7a240d, 0xd5ad, 0x4fd6, { 0xbe, 0x1c, 0xdf, 0xa4, 0x41, 0x5f, 0x55, 0x26 } }
+
+extern EFI_GUID gDtPlatformFormSetGuid;
+
+#endif
diff --git a/EmbeddedPkg/Drivers/DtPlatformDxe/DtPlatformHii.vfr b/EmbeddedPkg/Drivers/DtPlatformDxe/DtPlatformHii.vfr
new file mode 100644
index 000000000000..3516746c4d84
--- /dev/null
+++ b/EmbeddedPkg/Drivers/DtPlatformDxe/DtPlatformHii.vfr
@@ -0,0 +1,51 @@
+/** @file
+*
+*  Copyright (c) 2017, Linaro, Ltd. All rights reserved.
+*
+*  This program and the accompanying materials
+*  are licensed and made available under the terms and conditions of the BSD License
+*  which accompanies this distribution.  The full text of the license may be found at
+*  http://opensource.org/licenses/bsd-license.php
+*
+*  THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
+*  WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
+*
+**/
+
+#include "DtPlatformDxe.h"
+
+//
+// EFI Variable attributes
+//
+#define EFI_VARIABLE_NON_VOLATILE       0x00000001
+#define EFI_VARIABLE_BOOTSERVICE_ACCESS 0x00000002
+#define EFI_VARIABLE_RUNTIME_ACCESS     0x00000004
+#define EFI_VARIABLE_READ_ONLY          0x00000008
+
+formset
+  guid      = DT_PLATFORM_FORMSET_GUID,
+  title     = STRING_TOKEN(STR_FORM_SET_TITLE),
+  help      = STRING_TOKEN(STR_FORM_SET_TITLE_HELP),
+  classguid = EFI_HII_PLATFORM_SETUP_FORMSET_GUID,
+
+  efivarstore DT_ACPI_VARSTORE_DATA,
+    attribute = EFI_VARIABLE_BOOTSERVICE_ACCESS | EFI_VARIABLE_NON_VOLATILE,  // EFI variable attributes
+    name  = DtAcpiPref,
+    guid  = DT_PLATFORM_FORMSET_GUID;
+
+  form formid = 0x1000,
+    title  = STRING_TOKEN(STR_MAIN_FORM_TITLE);
+
+    oneof varid = DtAcpiPref.Pref,
+        prompt      = STRING_TOKEN(STR_DT_ACPI_SELECT_PROMPT),
+        help        = STRING_TOKEN(STR_DT_ACPI_SELECT_HELP),
+        flags       = NUMERIC_SIZE_1 | INTERACTIVE | RESET_REQUIRED,
+        option text = STRING_TOKEN(STR_DT_ACPI_SELECT_DT), value = DT_ACPI_SELECT_DT, flags = DEFAULT;
+        option text = STRING_TOKEN(STR_DT_ACPI_SELECT_ACPI), value = DT_ACPI_SELECT_ACPI, flags = 0;
+    endoneof;
+
+    subtitle text = STRING_TOKEN(STR_NULL_STRING);
+
+  endform;
+
+endformset;
diff --git a/EmbeddedPkg/Drivers/DtPlatformDxe/DtPlatformDxe.c b/EmbeddedPkg/Drivers/DtPlatformDxe/DtPlatformDxe.c
new file mode 100644
index 000000000000..f714551213c2
--- /dev/null
+++ b/EmbeddedPkg/Drivers/DtPlatformDxe/DtPlatformDxe.c
@@ -0,0 +1,216 @@
+/** @file
+*
+*  Copyright (c) 2017, Linaro, Ltd. All rights reserved.
+*
+*  This program and the accompanying materials
+*  are licensed and made available under the terms and conditions of the BSD License
+*  which accompanies this distribution.  The full text of the license may be found at
+*  http://opensource.org/licenses/bsd-license.php
+*
+*  THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
+*  WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
+*
+**/
+
+#include <Library/BaseLib.h>
+#include <Library/DebugLib.h>
+#include <Library/DevicePathLib.h>
+#include <Library/UefiLib.h>
+#include <Library/UefiDriverEntryPoint.h>
+#include <Library/UefiBootServicesTableLib.h>
+#include <Library/UefiRuntimeServicesTableLib.h>
+#include <Library/UefiHiiServicesLib.h>
+#include <Library/MemoryAllocationLib.h>
+#include <Library/HiiLib.h>
+#include <Library/PcdLib.h>
+#include <Library/DxeServicesLib.h>
+
+#include "DtPlatformDxe.h"
+
+extern  UINT8                     DtPlatformHiiBin[];
+extern  UINT8                     DtPlatformDxeStrings[];
+
+typedef struct {
+  VENDOR_DEVICE_PATH              VendorDevicePath;
+  EFI_DEVICE_PATH_PROTOCOL        End;
+} HII_VENDOR_DEVICE_PATH;
+
+STATIC HII_VENDOR_DEVICE_PATH     mDtPlatformDxeVendorDevicePath = {
+  {
+    {
+      HARDWARE_DEVICE_PATH,
+      HW_VENDOR_DP,
+      {
+        (UINT8) (sizeof (VENDOR_DEVICE_PATH)),
+        (UINT8) ((sizeof (VENDOR_DEVICE_PATH)) >> 8)
+      }
+    },
+    DT_PLATFORM_FORMSET_GUID
+  },
+  {
+    END_DEVICE_PATH_TYPE,
+    END_ENTIRE_DEVICE_PATH_SUBTYPE,
+    {
+      (UINT8) (END_DEVICE_PATH_LENGTH),
+      (UINT8) ((END_DEVICE_PATH_LENGTH) >> 8)
+    }
+  }
+};
+
+STATIC
+EFI_STATUS
+InstallHiiPages (
+  VOID
+  )
+{
+  EFI_STATUS                      Status;
+  EFI_HII_HANDLE                  HiiHandle;
+  EFI_HANDLE                      DriverHandle;
+
+  DriverHandle = NULL;
+  Status = gBS->InstallMultipleProtocolInterfaces (&DriverHandle,
+                  &gEfiDevicePathProtocolGuid,
+                  &mDtPlatformDxeVendorDevicePath,
+                  NULL);
+  if (EFI_ERROR (Status)) {
+    return Status;
+  }
+
+  HiiHandle = HiiAddPackages (&gDtPlatformFormSetGuid,
+                              DriverHandle,
+                              DtPlatformDxeStrings,
+                              DtPlatformHiiBin,
+                              NULL);
+
+  if (HiiHandle == NULL) {
+    gBS->UninstallMultipleProtocolInterfaces (DriverHandle,
+                  &gEfiDevicePathProtocolGuid,
+                  &mDtPlatformDxeVendorDevicePath,
+                  NULL);
+    return EFI_OUT_OF_RESOURCES;
+  }
+  return EFI_SUCCESS;
+}
+
+/**
+  The entry point for DtPlatformDxe driver.
+
+  @param[in] ImageHandle     The image handle of the driver.
+  @param[in] SystemTable     The system table.
+
+  @retval EFI_ALREADY_STARTED     The driver already exists in system.
+  @retval EFI_OUT_OF_RESOURCES    Fail to execute entry point due to lack of
+                                  resources.
+  @retval EFI_SUCCES              All the related protocols are installed on
+                                  the driver.
+
+**/
+EFI_STATUS
+EFIAPI
+DtPlatformDxeEntryPoint (
+  IN EFI_HANDLE                   ImageHandle,
+  IN EFI_SYSTEM_TABLE             *SystemTable
+  )
+{
+  EFI_STATUS                      Status;
+  DT_ACPI_VARSTORE_DATA           DtAcpiPref;
+  UINTN                           BufferSize;
+  VOID                            *Dtb;
+  UINTN                           DtbSize;
+  VOID                            *DtbCopy;
+
+  //
+  // Check whether a DTB blob is included in the firmware image.
+  //
+  Dtb = NULL;
+  Status = GetSectionFromAnyFv (&gDtPlatformDefaultDtbFileGuid,
+             EFI_SECTION_RAW, 0, &Dtb, &DtbSize);
+  if (EFI_ERROR (Status)) {
+    DEBUG ((DEBUG_WARN, "%a: no DTB blob found, defaulting to ACPI\n",
+      __FUNCTION__));
+    DtAcpiPref.Pref = DT_ACPI_SELECT_ACPI;
+  } else {
+    //
+    // Get the current DT/ACPI preference from the DtAcpiPref variable.
+    //
+    BufferSize = sizeof (DtAcpiPref);
+    Status = gRT->GetVariable(DT_ACPI_VARIABLE_NAME, &gDtPlatformFormSetGuid,
+                    NULL, &BufferSize, &DtAcpiPref);
+    if (EFI_ERROR (Status)) {
+      DEBUG ((DEBUG_WARN, "%a: no DT/ACPI preference found, defaulting to DT\n",
+        __FUNCTION__));
+      DtAcpiPref.Pref = DT_ACPI_SELECT_DT;
+    }
+  }
+
+  if (!EFI_ERROR (Status) &&
+      DtAcpiPref.Pref != DT_ACPI_SELECT_ACPI &&
+      DtAcpiPref.Pref != DT_ACPI_SELECT_DT) {
+    DEBUG ((DEBUG_WARN, "%a: invalid value for DtAcpiPref, defaulting to DT\n",
+      __FUNCTION__));
+    DtAcpiPref.Pref = DT_ACPI_SELECT_DT;
+    Status = EFI_INVALID_PARAMETER; // trigger setvar below
+  }
+
+  //
+  // Write the newly selected default value back to the variable store.
+  //
+  if (EFI_ERROR (Status)) {
+    Status = gRT->SetVariable(DT_ACPI_VARIABLE_NAME, &gDtPlatformFormSetGuid,
+                    EFI_VARIABLE_NON_VOLATILE | EFI_VARIABLE_BOOTSERVICE_ACCESS,
+                    sizeof (DtAcpiPref), &DtAcpiPref);
+    if (EFI_ERROR (Status)) {
+      return Status;
+    }
+  }
+
+  if (DtAcpiPref.Pref == DT_ACPI_SELECT_ACPI) {
+    //
+    // ACPI was selected: install the gEdkiiPlatformHasAcpiGuid GUID as a
+    // NULL protocol to unlock dispatch of ACPI related drivers.
+    //
+    Status = gBS->InstallMultipleProtocolInterfaces (&ImageHandle,
+                    &gEdkiiPlatformHasAcpiGuid, NULL, NULL);
+    if (EFI_ERROR (Status)) {
+      DEBUG ((DEBUG_ERROR,
+        "%a: failed to install gEdkiiPlatformHasAcpiGuid as a protocol\n",
+        __FUNCTION__));
+      return Status;
+    }
+  } else if (DtAcpiPref.Pref == DT_ACPI_SELECT_DT) {
+    //
+    // DT was selected: copy the blob into newly allocated memory and install
+    // a reference to it as the FDT configuration table.
+    //
+    DtbCopy = AllocateCopyPool (DtbSize, Dtb);
+    if (DtbCopy == NULL) {
+      return EFI_OUT_OF_RESOURCES;
+    }
+    Status = gBS->InstallConfigurationTable (&gFdtTableGuid, DtbCopy);
+    if (EFI_ERROR (Status)) {
+      DEBUG ((DEBUG_ERROR, "%a: failed to install FDT configuration table\n",
+        __FUNCTION__));
+      FreePool (DtbCopy);
+      return Status;
+    }
+  } else {
+    ASSERT (FALSE);
+  }
+
+  //
+  // No point in installing the HII pages if ACPI is the only description
+  // we have
+  //
+  if (Dtb == NULL) {
+    return EFI_SUCCESS;
+  }
+
+  //
+  // Note that we don't uninstall the gEdkiiPlatformHasAcpiGuid protocol nor
+  // the FDT configuration table if the following call fails. While that will
+  // cause loading of this driver to fail, proceeding with ACPI and DT both
+  // disabled will guarantee a failed boot, and so it is better to leave them
+  // installed in that case.
+  //
+  return InstallHiiPages ();
+}
diff --git a/EmbeddedPkg/Drivers/DtPlatformDxe/DtPlatformHii.uni b/EmbeddedPkg/Drivers/DtPlatformDxe/DtPlatformHii.uni
new file mode 100644
index 000000000000..bc995c1d0fbd
--- /dev/null
+++ b/EmbeddedPkg/Drivers/DtPlatformDxe/DtPlatformHii.uni
@@ -0,0 +1,27 @@
+/** @file
+*
+*  Copyright (c) 2017, Linaro, Ltd. All rights reserved.
+*
+*  This program and the accompanying materials
+*  are licensed and made available under the terms and conditions of the BSD License
+*  which accompanies this distribution.  The full text of the license may be found at
+*  http://opensource.org/licenses/bsd-license.php
+*
+*  THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
+*  WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
+*
+**/
+
+#langdef en-US  "English"
+
+#string STR_FORM_SET_TITLE             #language en-US "O/S Hardware Description Selection"
+#string STR_FORM_SET_TITLE_HELP        #language en-US "Press <Enter> to choose between ACPI and DT hardware descriptions."
+
+#string STR_MAIN_FORM_TITLE            #language en-US "O/S Hardware Description Selection"
+#string STR_NULL_STRING                #language en-US ""
+
+#string STR_DT_ACPI_SELECT_PROMPT      #language en-US "O/S Hardware Description"
+#string STR_DT_ACPI_SELECT_HELP        #language en-US "Select the hardware description that will be exposed to the O/S."
+
+#string STR_DT_ACPI_SELECT_DT          #language en-US "Device Tree"
+#string STR_DT_ACPI_SELECT_ACPI        #language en-US "ACPI"
-- 
2.9.3