82598EB Datasheet, PDF (121/596 Pages) Intel Corporation – Intel® 82598EB 10 Gigabit Ethernet Controller Datasheet

Intel^® 82598EB 10 GbE Controller - Network Interface
3.1.4.6 MAC Speed Change at Different Power Modes
Normal speed negotiation drives to establish a link at the highest possible speed. the The 82598
supports an additional mode of operation, where the MAC drives to establish a link at a low speed. The
link-up process allows a link to come up at any possible speed in cases where power is more important
than performance. Different behavior is defined for the D0 state and the other non-D0 states.
The 82598 might initiate auto negotiation w/o direct driver command in the following cases:
• When the state of MAIN_PWR_OK pin changes.
• When the MNG_VETO bit value changes.
• On a transition from D0a state to a non-D0a state, or from a non-D0a state to D0a state.
The following figure shows the behavior when going to low power mode.
Figure 3-9. Transition to Low-Power Mode
The following figure shows the behavior when going to power-up mode.
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