HT Link Disconnect/Reconnect Sequence
The specification defines the ability of the HT bus to disconnect all of its links simultaneously. This mechanism uses the LDTSTOP# signal and NOP packet (with disconnect bit set) to gracefully disconnect and subsequently reconnect all links within the HT fabric. This feature has five specified uses:
Disconnecting HT links to conserve power
An alternate and faster method of changing link frequency and width during initialization, when compared to Soft Reset
Support for Host Voltage ID and Frequency ID (VID/FID) change
Processor is entering certain ACPI-specified states
System is entering certain ACPI-specified states
Regardless of the system motivation for asserting LDTSTOP# the sequence of events associated ...