GTS AXI Streaming Intel® FPGA IP for PCI Express* User Guide

ID 813754
Date 4/07/2025
Public

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4.10.1. Endpoint D3 Entry

  1. 1. The power management software must ensure that all outstanding non-posted requests have received their associated completions by polling that Transaction Pending bit in the Device Status register. Only then, it can put a function into D3hot state by writing the appropriate value into the PowerState field of its Power Management Control and Status register.
  2. The link is forced to L1 state when the function changes to D3hot state. In this state, the function can only initiate PME or PME_TO_ACK messages and can only respond to configuration requests or the PME_Turn_Off message.
  3. The power management software sends the PME_Turn_Off message to the Endpoint to initiate power down. The delivery of the message TLP causes the link to transition to L0 and the message is also passed on to the AXI Stream RX interface.
  4. The IP core auto transmits a PME_TO_Ack message to acknowledge the Turn Off request.
  5. When the user application is ready to enter L2 state, it writes 1 to bit[2] of the POWER MANAGEMENT CTRL register to indicate that it is ready to enter the L23 state. The IP core sends a PM_Enter_L23 DLLP when this bit is set and clears the bit when the requested operation is complete.
  6. The reference clock and power can be removed when the link has transitioned to the L23 Ready state. The link then enters L2 state as auxiliary power VAUX is always present.