Advanced Configuration and Power Interface Specification

Device Configuration
Offset Field Name Definition
Byte 55
Type Specific Attribute,
_ATT bits[63:56]
See Section 19.6.43, “ExtendedSpace (Extended Address Space Resource Descriptor Macro),” for a
description of the ASL macro that creates an Extended Address Space descriptor.
6.4.3.5.4.1 Type Specific Attributes
The meaning of the Type Specific Attributes field of the Extended Address Space Descriptor
depends on the value of the Resource Type field in the descriptor. When Resource Type = 0
(memory resource), the Type Specific Attributes field values are defined per Memory Attribute
Definitions in the UEFI Specification under section titled GetMemoryMap().
6.4.3.5.5 Resource Type Specific Flags
The meaning of the flags in the Type Specific Flags field of the Address Space Descriptors depends
on the value of the Resource Type field in the descriptor. The flags for each resource type are
defined in the following tables:
Table 6-213 Memory Resource Flag (Resource Type = 0) Definitions
Bits Meaning
Bits [7:6] Reserved (must be 0)
Bit [5] Memory to I/O Translation, _TTP
1 TypeTranslation: This resource, which is memory on the secondary side of the bridge, is
I/O on the primary side of the bridge.
0 TypeStatic: This resource, which is memory on the secondary side of the bridge, is also
memory on the primary side of the bridge.
Bits [4:3] Memory attributes, _MTP.
These bits are only defined if this memory resource describes system RAM. For a definition of
the labels described here, see Section 15, “System Address Map Interfaces.”
0 AddressRangeMemory
1 AddressRangeReserved
2 AddressRangeACPI
3 AddressRangeNVS
Bits [2:1] Memory attributes, _MEM
0 The memory is non-cacheable.
1 The memory is cacheable.
2 The memory is cacheable and supports write combining.
3 The memory is cacheable and prefetchable.
(Notice: OSPM ignores this field in the Extended address space descriptor. Instead it uses the
Type Specific Attributes field to determine memory attributes)
Bit [0]
Write status, _RW
1 This memory range is read-write.
0 This memory range is read-only.
Version 6.0 365