• Naga Chumbalkar's avatar
    [CPUFREQ] Processor Clocking Control interface driver · 0f1d683f
    Naga Chumbalkar authored
    Processor Clocking Control (PCC) is an interface between the BIOS and OSPM.
    Based on the server workload, OSPM can request what frequency it expects
    from a logical CPU, and the BIOS will achieve that frequency transparently.
    
    This patch introduces driver support for PCC. OSPM uses the PCC driver to
    communicate with the BIOS via the PCC interface.
    
    There is a Documentation file that provides a link to the PCC
    Specification, and also provides a summary of the PCC interface.
    
    Currently, certain HP ProLiant platforms implement the PCC interface. However,
    any platform whose BIOS implements the PCC Specification, can utilize this
    driver.
    
    V2 --> V1 changes (based on Dominik's suggestions):
    - Removed the dependency on CPU_FREQ_TABLE
    - "cpufreq_stats" will no longer PANIC. Actually, it will not load anymore
    because it is not applicable.
    - Removed the sanity check for target frequency in the ->target routine.
    
    NOTE: A patch to sanitize the target frequency requested by "ondemand" is
    needed to ensure that the target freq < policy->min.
    
    Can this driver be queued up for the 2.6.33 tree?
    Signed-off-by: default avatarNaga Chumbalkar <nagananda.chumbalkar@hp.com>
    Signed-off-by: default avatarMatthew Garrett <mjg@redhat.com>
    Signed-off-by: default avatarThomas Renninger <trenn@suse.de>
    Signed-off-by: default avatarDave Jones <davej@redhat.com>
    0f1d683f
pcc-cpufreq.c 15.4 KB