GTS AXI Streaming IP for PCI Express* User Guide: Agilex™ 5 and Agilex™ 3 FPGAs and SoCs
4.10.2. Endpoint L2 Exit
The host system or root port transits into Detect link state and starts to send Electrical Idle order set upon power-up. When the endpoint receives Electrical Idle order set during the L2 link state, it triggers a reset to the PCIe* IP core before transiting into to Detect link state. Alternatively, the user application can initiate wake-up from L2 state by writing a 1 to bit[0] of the POWER MANAGEMENT CTRL register. When the controller has transitioned back to the L0 state it transmits a PME message and sets the PME_Status. Upon receiving the PME message the root complex should clear the PME_Status and change the D-state back to D0. The bit[0] of the POWER MANAGEMENT CTRL register is cleared indicating the requested operation is complete.