Dynanic On-The-Fly Operating points for PowerOP

[David Singleton <dsingleton@mvista.com>]

The patches provided in the following three emails continue the unified,
        simplified PowerOp concept of power management.  The patches
        can be found at:

                http://source.mvista.com/~dsingleton

                        powerop-core.patch
                        powerop-cpufreq.patch
                        powerop-x86-centrino.patch


                The patches break the working PowerOP feature into
        three logical parts.  The first patch is the powerop-core.patch
        that adds support for an operating point in the standard linux
        power management infrastructure (CONFIG_PM) and adds a new
        function to perform transitioning to operating points other
        than suspend to memory or disk.

                The second patch, powerop-cpufreq.patch, adds the cpufreq
        portion of the patch that makes cpufreq tables a set of PowerOp
        operating points.

                The third patch, powerop-x86-centrino.patch, adds
        operating points for all the centrino-speedstep processors.


        This set of patches has changed in the following ways.

        1) The patch is now broken out of the cpufreq code and implements
        operating points for whatever speedstep-centrino the system
        detects upon boot.

        2) The naming scheme for operating points has been unified to
        provide a better interface to the PowerOp power manager daemon.
        The names range from:

                        highest
                        high
                        medhigh
                        medium
                        medlow
                        low
                        lowest

        PowerOp maps the supported processor frequencies onto this
        namespace list.  The set of centrino processors it supports have
        supported sets of between four and six different operating points.

        The PowerOP daemon, coming soon, can simply read the supported
        set of operating points and make some simple rules based
        decisions about when to transition to various operating points.

        The goal of a unified name space is to provide a PowerOp manager
        that runs out of the box, with very little setup by the user.


        3) This patch supports the ability to provide dynamic, on-the-fly
        operating points to the framework via a loadable module.  The 
operating
        point parameters of frequency, voltage and transition latency
        can be passed at insmod time to create any new operating point
        the centrino hardware will support.


        I think I finally understand the 'why' of hardware vendors asking
        for a requirement of dynamic, on the fly, operating points.

        I have two sets of hardware that support a wide range of
        processor speeds and voltages depending on:

        a) the rotary and dip switch setting of the board (the mainstone).

        or

        b) the revision or stepping of the hardware on the board.

        Certain revs of hardware support different frequencies and 
voltages.
        Some steppings won't run all the frequencies.

        The hardware vendors want to provide support for all the
        frequencies and voltages that the system could support,
        depending on the switch settings or rev of hardware without
        having to change kernel code and recompile the kernel.

        The new dynamic, on the fly, operating point module will allow
        for this feature.


David