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The ACPI driver supports the IOCTL_ACPI_EVAL_METHOD request. A driver for a device can use this request to evaluate a control method that is an immediate child object in the ACPI namespace of the device to which the request is sent. The IOCTL_ACPI_EVAL_METHOD request supports the following input structures:
| Input structure | Description |
|---|---|
| ACPI_EVAL_INPUT_BUFFER | Supplies the signature of the buffer and the name of a control method that does not take an input argument. |
| ACPI_EVAL_INPUT_BUFFER_SIMPLE_INTEGER | Supplies the signature of the structure, the name of a control method, and a single input argument value of type ULONG. |
| ACPI_EVAL_INPUT_BUFFER_SIMPLE_STRING | Supplies the signature of the structure, the name of a control method, and an input argument that is a NULL-terminated ASCII string. |
| ACPI_EVAL_INPUT_BUFFER_COMPLEX | Supplies the signature of the structure, the name of a control method, and an input array of ACPI_METHOD_ARGUMENT structures. The array can contain a maximum number of seven such structures. An ACPI_METHOD_ARGUMENT structure can contain a ULONG integer, an ASCII string, an ACPI package description, or an array of custom data. |
Windows also supports the IOCTL_ACPI_EVAL_METHOD_EX request. A driver for a device can use this request to evaluate a control method that is a descendant child object in the ACPI namespace of the device to which the request is sent. The IOCTL_ACPI_EVAL_METHOD_EX request supports the following input structures:
| Input structure | Description |
|---|---|
| ACPI_EVAL_INPUT_BUFFER_EX | supplies the signature of the structure and the path and name of a control method that does not take an input argument. |
| ACPI_EVAL_INPUT_BUFFER_SIMPLE_INTEGER_EX | supplies the signature of the structure and the path and name of a control method that takes a single integer of type ULONG64 as an input argument. |
| ACPI_EVAL_INPUT_BUFFER_SIMPLE_STRING_EX | supplies the signature of the structure and the path and name of a control method that takes a single NULL-terminated ASCII string as an input argument. |
| ACPI_EVAL_INPUT_BUFFER_COMPLEX_EX | supplies the signature of the structure and the path and name of a control method that takes an array of ACPI_METHOD_ARGUMENT structures as input. The array can contain a maximum number of seven such structures. An ACPI_METHOD_ARGUMENT structure can contain a ULONG integer, an ASCII string, an ACPI package description, or an array of custom data. |
To obtain the path and name of child objects in the ACPI namespace of a device, a driver for a device can use an IOCTL_ACPI_ENUM_CHILDREN request, as described in Enumerating Child Devices and Control Methods.