For example, in the PCIe L1.2 power-saving mode shown in Figure 3, when CLKREQ# is pulled up, the root complex (RC) stops outputting the reference frequency, and both sides enter power-saving mode; ...

PCI Express offers many such scopes for clock gating at local as well as broader level. Among these is the CLKREQ# protocol which allows the reference clock from the platform to be turned off. This in ...