The following device management feature has been added to the Solaris 10 5/09 release.
This feature provides the basic CPU Advanced Configuration and Power Interface (ACPI) T-state support. T-state support enables the CPU driver to receive _TPC change notifications as a manner of controlling the processor speed. This is frequently done on some systems as a passive cooling mechanism along with the existing CPU ACPI P-States.
For more information, see http://opensolaris.org/os/community/pm/.