Reporting Power Management Events to the Host Bridge
HT provides two System Management messages that can be used to report power management events to the host.
STPCLK message — uses the SMAF field to define the type of event being reported and the action to be taken. The SMAF field encoding is not defined by the HT specification.
SMI message — used to notify (interrupt) the processor when a system management event occurs. The SMI message can support power management as will as other features. (Note: SMI is an x86 legacy signal and is discussed in more detail in “X86 CPU Compatibility” on page 491.)
Message transmission may be stimulated by either hardware or software. A system that supports power management will very likely include a set of registers ...