Advanced Configuration and Power Interface Specification

Advanced Configuration and Power Interface Specification
Note: Mixing of 24-bit and 32-bit memory descriptors on the same device is not allowed.
See Section 19.6.81, “Memory32Fixed (Memory Resource Descriptor),” for a description of the
ASL macro that creates a 32-bit Fixed Memory descriptor.
6.4.3.5 Address Space Resource Descriptors
The QWORD, DWORD, WORD, and Extended Address Space Descriptors are general-purpose
structures for describing a variety of types of resources. These resources also include support for
advanced server architectures (such as multiple root buses), and resource types found on some RISC
processors. These descriptors can describe various kinds of resources. The following table defines
the valid combination of each field and how they should be interpreted.
Table 6-208 Valid combination of Address Space Descriptors fields
_LEN _MIF _MAF Definition
0 0 0 Variable size, variable location resource descriptor for _PRS.
0 0 1 If _MIF is set, _MIN must be a multiple of (_GRA+1). If _MAF is set, _MAX must be
0 1 0
(a multiple of (_GRA+1))-1.
OS can pick the resource range that satisfies following conditions:
If _MIF is not set, start address is a multiple of (_GRA+1) and greater or equal to
_MIN. Otherwise, start address is _MIN.
If _MAF is not set, end address is (a multiple of (_GRA+1))-1 and less or equal to
_MAX. Otherwise, end address is _MAX.
0 1 1 (Invalid combination)
> 0 0 0 Fixed size, variable location resource descriptor for _PRS.
_LEN must be a multiple of (_GRA+1).
OS can pick the resource range that satisfies following conditions:
Start address is a multiple of (_GRA+1) and greater or equal to _MIN.
End address is (start address+_LEN-1) and less or equal to _MAX.
> 0 0 1 (Invalid combination)
> 0 1 0 (Invalid combination)
> 0 1 1 Fixed size, fixed location resource descriptor.
_GRA must be 0 and _LEN must be (_MAX - _MIN +1).
6.4.3.5.1 QWord Address Space Descriptor
Type 1, Large Item Name 0xA
The QWORD address space descriptor is used to report resource usage in a 64-bit address space
(like memory and I/O).
Table 6-209 QWORD Address Space Descriptor Definition
Offset Field Name Definition
Byte 0 QWORD Address Space Value = 0x8A (10001010B) – Type = 1, Large item name = 0x0A
Descriptor
Byte 1 Length, bits[7:0] Variable length, minimum value = 0x2B (43)
Byte 2 Length, bits[15:8] Variable length, minimum value = 0x00
354 April, 2015 Version 6.0