piixpcib(4) - NetBSD Manual Pages

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PIIXPCIB(4)             NetBSD Kernel Interfaces Manual            PIIXPCIB(4)


NAME

     piixpcib -- Intel PIIX4 PCI-ISA bridge with SpeedStep


SYNOPSIS

     piixpcib* at pci? dev ? function ?
     isa* at piixpcib?


DESCRIPTION

     The piixpcib driver provides support for the Intel PIIX and compatible
     PCI-ISA Bridges with Intel's first generation SpeedStep.

     Frequency scaling is supported on Pentium III with two voltage modes,
     used by SpeedStep as power states low and high.  The driver will switch
     into low power state by reducing voltage and frequency of the CPU.  The
     factor depends on the processor itself, but will always reduce power con-
     sumption about 1/2.

     The user can manually control the CPU frequency with the sysctl(8) pro-
     gram using the following node:

           machdep.speedstep_state = [0/1]


SEE ALSO

     est(4), isa(4), pci(4), apmd(8), sysctl(8)


HISTORY

     The piixpcib driver first appeared in FreeBSD 5.5 and then in NetBSD 4.0.


AUTHORS

     The current piixpcib driver was written by Bruno Ducrot.  It was ported
     to NetBSD by Jared D. McNeill <jmcneill@NetBSD.org>.

NetBSD 10.1                      March 1, 2011                     NetBSD 10.1