Processor Configuration Registers
2.12.15 DMIVCMRCTL—DMI VCm Resource Control Register
B/D/F/Type:
Address Offset:
Reset Value:
Access:
0/0/0/DMIBAR
38–3Bh
07000080h
RW, RO
32 bits
00000h
Size:
BIOS Optimal Default
Reset
Value
RST/
PWR
Bit
Access
Description
Virtual Channel enable (VCMEN)
0 = Virtual Channel is disabled.
1 = Virtual Channel is enabled. See exceptions below.
Software must use the VC Negotiation Pending bit to check
whether the VC negotiation is complete. When VC Negotiation
Pending bit is cleared, a 1 read from this VC Enable bit indicates
that the VC is enabled (Flow Control Initialization is completed for
the PCI Express port). A 0 read from this bit indicates that the
Virtual Channel is currently disabled.
31
RW
0b
Uncore
BIOS Requirement:
1.
To enable a Virtual Channel, the VC Enable bits for that
Virtual Channel must be set in both Components on a Link.
To disable a Virtual Channel, the VC Enable bits for that
Virtual Channel must be cleared in both Components on a
Link.
2.
3.
4.
Software must ensure that no traffic is using a Virtual
Channel at the time it is disabled.
Software must fully disable a Virtual Channel in both
Components on a Link before re-enabling the Virtual
Channel.
30:27
26:24
23:8
RO
RW
RO
0h
111b
0h
Reserved (RSVD)
Virtual Channel ID (VCID)
This field assigns a VC ID to the VC resource. Assigned value
must be non-zero. This field cannot be modified when the VC is
already enabled.
Uncore
Reserved (RSVD)
Traffic Class/Virtual Channel Map (TCVCMMAP):
This field indicates the TCs (Traffic Classes) that are mapped to
the VC resource. Bit locations within this field correspond to TC
values.
For example, when bit 7 is set in this field, TC7 is mapped to this
VC resource. When more than one bit in this field is set, it
indicates that multiple TCs are mapped to the VC resource. In
order to remove one or more TCs from the TC/VC Map of an
enabled VC, software must ensure that no new or outstanding
transactions with the TC labels are targeted at the given Link.
7:0
RO
80h
Uncore
Datasheet, Volume 2
227
INTEL [ INTEL ]
