Link Wake Protocol and PME Generation

The wake protocol provides a method for devices to reactivate the upstream link and request that Power Management software return the devices to D0 so they can perform required operations. The procedures and signaling methods used in PCI Express are different from the PCI-PM specified methods. However, PCI Express PM is designed to be compatible with PCI-PM software.

Rather than using the PCI-defined PME# sideband signal, PCI Express devices employ an inband PME message to notify PM software of a request to return the device to the full power state (D0). The ability to generate PME messages may be supported optionally within any of the low power states. Recall that devices report the PM states they support ...

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