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1.3 Phy layer
C141-C013 43
1.3.6.2 When the speed negotiation sequence is successful
When the speed negotiation sequence is successful, the identification sequence
(sending and receiving the IDENTIFY frame) is performed subsequently.
However, the INIT may have started the hard reset sequence at the time when the
drive starts the identification sequence. In this case, the drive will start the link
reset sequence, because it receives the HARD_RESET.
1.3.6.3 Exception handling in the speed negotiation sequence
• When synchronization cannot be established at the G1 or G2 rate
• When synchronization cannot be established at the last negotiated rate
In both of the cases referred to above, the speed negotiation sequence is
considered to have failed. The drive waits for the reception of the COMINIT
signal from the INIT or expander until the hot-plug timeout time (500 ms) elapses.
When the hot-plug timeout time elapses before the signal has been received from
the other side, the drive sends the COMINIT signal again to start a new link reset
sequence. At the same time, the value in the PHY RESET PROBLEM field of the
Protocol-Specific log page (page 18) is incremented when synchronization cannot
be established at the last negotiated rate.
1.3.7 Phy layer dword synchronization (DWS)
The dword synchronization monitoring performed by the drive after the
completion of the speed negotiation sequence has the following characteristics:
1) When four invalid dwords are detected in a frame (address frame or SSP
frame), the dword synchronization is considered to have been lost. At this
time, the drive starts the link reset sequence without monitoring whether any
valid primitive is received (and without trying to establish re-
synchronization).
2) If an invalid dword is detected in the idle state (the state where random data
is being sent and/or received without transfer of frames or primitives), the
DWS Reset timeout timer (1 ms) is started. If at least one valid primitive is
detected within 1 ms, the monitoring assumes that the drive is in the
SynAcquired state (the state that the dword synchronization is established).
Otherwise, the drive starts the link reset sequence.