Thermal Specifications
cleared. In the event that this timeout occurs, the originating agent will receive a failed
completion code upon issuing a MbxGet() command, or even worse, it may receive
corrupt data if this MbxGet() command so happens to be interleaved with an
MbxSend() from another process. Please refer to Table 6-13 for more information
regarding failed completion codes from MbxGet() commands.
Timeouts are undesirable, and the best way to avoid them and guarantee valid data is
for the originating agent to always issue MbxGet() commands immediately following
MbxSend() commands.
Alternately, mailbox timeout can be disabled. The BIOS may write MSR
MISC_POWER_MGMT (0x1AA), bit 11 to 0b1 in order to force a disable of this
automatic timeout.
6.3.2.9.5
Response Latency
The PECI mailbox interface is designed to have response data available within plenty of
margin to allow for back-to-back MbxSend() and MbxGet() requests. However, under
rare circumstances that are out of the scope of this specification, it is possible that the
response data is not available when the MbxGet() command is issued. Under these
circumstances, the MbxGet() command will respond with an Abort FCS and the
originator should re-issue the MbxGet() request.
6.3.3
Multi-Domain Commands
The Intel Xeon Processor E7-8800/4800/2800 Product Families processor does not
support multiple domains, but it is possible that future products will, and the following
tables are included as a reference for domain-specific definitions.
Table 6-14. Domain ID Definition
Domain ID
Domain Number
0b01
0b10
0
1
Table 6-15. Multi-Domain Command Code Reference
Domain 0
Domain 1
Code
Command Name
Code
GetTemp()
0x01
0xC1
0xC5
0xD1
0xD5
0x02
0xC2
0xC6
0xD2
0xD6
PCIConfigRd()
PCIConfigWr()
MbxSend()
MbxGet()
6.3.4
Client Responses
6.3.4.1
Abort FCS
The Client responds with an Abort FCS under the following conditions:
• The decoded command is not understood or not supported on this processor (this
includes good command codes with bad Read Length or Write Length bytes).
• Data is not ready.
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Datasheet Volume 1 of 2
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