IBM Intel Xeon E5606 49Y3776 User Manual

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Note that the 4-byte data defined above is sent in standard PECI ordering with LSB first 
and MSB last.

If MbxSend() response returns a bad FCS in the data, the completion code can't be 
trusted and the semaphore may or may not be taken. In order to clean out the 
interface, an MbxGet() must be issued and the response data should be discarded.

The MbxGet() command is utilized for retrieving response data from the generic 
Mailbox interface as well as for unlocking the acquired mailbox. Please refer to 

 for details regarding the MbxSend() command. Many of the 

fundamental concepts of Mailbox ownership, release, and management are discussed 
in 

.

The MbxGet() command is designed to retrieve response data from a previously 
deposited request. In order to guarantee alignment between the temporally separated 
request (MbxSend) and response (MbxGet) commands, the originally granted 
Transaction ID (sent as part of the passing MbxSend() completion code) must be issued 
as part of the MbxGet() request.

Any mailbox request made with an illegal or unlocked Transaction ID will get a failed 
completion code response. If the Transaction ID matches an outstanding transaction ID 
associated with a locked mailbox, the command will complete successfully and the 
response data will be returned to the originator.

Byte #

Byte 

Definition

0

Client Address

1

Write Length

0x07

2

Read Length

0x01

10

FCS

3

Cmd Code

0xd1

11

Completion

Code

12

FCS

5

6

7

8

LSB

MSB

Data[31:0]

10

11

9

AW FCS

4

Request Type

Bad FCS

Electrical error

 0x4X

Semaphore is granted with a Transaction ID of ‘X’

0x80

Error causing a response timeout. Either due to a rare, internal timing condition or a 

processor RESET condition or processor S1 state. Retry is appropriate outside of the 

RESET or S1 states.

 0x86

Mailbox interface is unavailable or busy