Linux内核学习笔记——ACPI命名空间

所有定义块都加载到单个命名空间中。命名空间 是由名称和路径标识的对象层次结构。 以下命名约定适用于 ACPI 中的对象名称 命名空间：

所有名称的长度均为 32 位。

名称的第一个字节必须是“A”-“Z”、“_”之一。

名称的每个剩余字节必须是“A”-“Z”、“0”之一 - ‘9’, ‘_’.

以“_”开头的名称由 ACPI 规范保留。

“”符号表示命名空间的根（即名称 前缀为 ‘’ 是相对于命名空间根目录的）。

“^”符号表示当前命名空间节点的父节点 （即以“^”开头的名称相对于 当前命名空间节点）。

下图显示了一个示例 ACPI 命名空间：

+------+
| \    |                     Root
+------+
  |
  | +------+
  +-| _PR  |                 Scope(_PR): the processor namespace
  | +------+
  |   |
  |   | +------+
  |   +-| CPU0 |             Processor(CPU0): the first processor
  |     +------+
  |
  | +------+
  +-| _SB  |                 Scope(_SB): the system bus namespace
  | +------+
  |   |
  |   | +------+
  |   +-| LID0 |             Device(LID0); the lid device
  |   | +------+
  |   |   |
  |   |   | +------+
  |   |   +-| _HID |         Name(_HID, "PNP0C0D"): the hardware ID
  |   |   | +------+
  |   |   |
  |   |   | +------+
  |   |   +-| _STA |         Method(_STA): the status control method
  |   |     +------+
  |   |
  |   | +------+
  |   +-| PCI0 |             Device(PCI0); the PCI root bridge
  |     +------+
  |       |
  |       | +------+
  |       +-| _HID |         Name(_HID, "PNP0A08"): the hardware ID
  |       | +------+
  |       |
  |       | +------+
  |       +-| _CID |         Name(_CID, "PNP0A03"): the compatible ID
  |       | +------+
  |       |
  |       | +------+
  |       +-| RP03 |         Scope(RP03): the PCI0 power scope
  |       | +------+
  |       |   |
  |       |   | +------+
  |       |   +-| PXP3 |     PowerResource(PXP3): the PCI0 power resource
  |       |     +------+
  |       |
  |       | +------+
  |       +-| GFX0 |         Device(GFX0): the graphics adapter
  |         +------+
  |           |
  |           | +------+
  |           +-| _ADR |     Name(_ADR, 0x00020000): the PCI bus address
  |           | +------+
  |           |
  |           | +------+
  |           +-| DD01 |     Device(DD01): the LCD output device
  |             +------+
  |               |
  |               | +------+
  |               +-| _BCL | Method(_BCL): the backlight control method
  |                 +------+
  |
  | +------+
  +-| _TZ  |                 Scope(_TZ): the thermal zone namespace
  | +------+
  |   |
  |   | +------+
  |   +-| FN00 |             PowerResource(FN00): the FAN0 power resource
  |   | +------+
  |   |
  |   | +------+
  |   +-| FAN0 |             Device(FAN0): the FAN0 cooling device
  |   | +------+
  |   |   |
  |   |   | +------+
  |   |   +-| _HID |         Name(_HID, "PNP0A0B"): the hardware ID
  |   |     +------+
  |   |
  |   | +------+
  |   +-| TZ00 |             ThermalZone(TZ00); the FAN thermal zone
  |     +------+
  |
  | +------+
  +-| _GPE |                 Scope(_GPE): the GPE namespace
    +------+

                  Figure 2. Example ACPI Namespace

Linux ACPI 设备树

结构acpi_device对象的 sysfs 层次结构对应于 图 2 中所示的示例 ACPI 命名空间，添加了 固定PWR_BUTTON/SLP_BUTTON设备如下所示：

+--------------+---+-----------------+
| LNXSYSTEM:00 | \ | acpi:LNXSYSTEM: |
+--------------+---+-----------------+
  |
  | +-------------+-----+----------------+
  +-| LNXPWRBN:00 | N/A | acpi:LNXPWRBN: |
  | +-------------+-----+----------------+
  |
  | +-------------+-----+----------------+
  +-| LNXSLPBN:00 | N/A | acpi:LNXSLPBN: |
  | +-------------+-----+----------------+
  |
  | +-----------+------------+--------------+
  +-| LNXCPU:00 | \_PR_.CPU0 | acpi:LNXCPU: |
  | +-----------+------------+--------------+
  |
  | +-------------+-------+----------------+
  +-| LNXSYBUS:00 | \_SB_ | acpi:LNXSYBUS: |
  | +-------------+-------+----------------+
  |   |
  |   | +- - - - - - - +- - - - - - +- - - - - - - -+
  |   +-| PNP0C0D:00 | \_SB_.LID0 | acpi:PNP0C0D: |
  |   | +- - - - - - - +- - - - - - +- - - - - - - -+
  |   |
  |   | +------------+------------+-----------------------+
  |   +-| PNP0A08:00 | \_SB_.PCI0 | acpi:PNP0A08:PNP0A03: |
  |     +------------+------------+-----------------------+
  |       |
  |       | +-----------+-----------------+-----+
  |       +-| device:00 | \_SB_.PCI0.RP03 | N/A |
  |       | +-----------+-----------------+-----+
  |       |   |
  |       |   | +-------------+----------------------+----------------+
  |       |   +-| LNXPOWER:00 | \_SB_.PCI0.RP03.PXP3 | acpi:LNXPOWER: |
  |       |     +-------------+----------------------+----------------+
  |       |
  |       | +-------------+-----------------+----------------+
  |       +-| LNXVIDEO:00 | \_SB_.PCI0.GFX0 | acpi:LNXVIDEO: |
  |         +-------------+-----------------+----------------+
  |           |
  |           | +-----------+-----------------+-----+
  |           +-| device:01 | \_SB_.PCI0.DD01 | N/A |
  |             +-----------+-----------------+-----+
  |
  | +-------------+-------+----------------+
  +-| LNXSYBUS:01 | \_TZ_ | acpi:LNXSYBUS: |
    +-------------+-------+----------------+
      |
      | +-------------+------------+----------------+
      +-| LNXPOWER:0a | \_TZ_.FN00 | acpi:LNXPOWER: |
      | +-------------+------------+----------------+
      |
      | +------------+------------+---------------+
      +-| PNP0C0B:00 | \_TZ_.FAN0 | acpi:PNP0C0B: |
      | +------------+------------+---------------+
      |
      | +-------------+------------+----------------+
      +-| LNXTHERM:00 | \_TZ_.TZ00 | acpi:LNXTHERM: |
        +-------------+------------+----------------+

               Figure 3. Example Linux ACPI Device Tree

注意

每个节点都表示为“对象/路径/模态别名”，其中：

“对象”是 sysfs 中对象目录的名称。

“path”是相应 ACPI 命名空间对象，由对象的“路径”返回 系统属性。

‘modalias’ 是对象的 ‘modalias’ sysfs 的值 属性（如本文档前面所述）。