• Matthew Garrett's avatar
    [CPUFREQ] Disable sysfs ui for p4-clockmod. · e088e4c9
    Matthew Garrett authored
    p4-clockmod has a long history of abuse.   It pretends to be a CPU
    frequency scaling driver, even though it doesn't actually change
    the CPU frequency, but instead just modulates the frequency with
    wait-states.
    The biggest misconception is that when running at the lower 'frequency'
    p4-clockmod is saving power.  This isn't the case, as workloads running
    slower take longer to complete, preventing the CPU from entering deep C states.
    
    However p4-clockmod does have a purpose.  It can prevent overheating.
    Having it hooked up to the cpufreq interfaces is the wrong way to achieve
    cooling however. It should instead be hooked up to ACPI.
    
    This diff introduces a means for a cpufreq driver to register with the
    cpufreq core, but not present a sysfs interface.
    Signed-off-by: default avatarMatthew Garrett <mjg@redhat.com>
    Signed-off-by: default avatarDave Jones <davej@redhat.com>
    e088e4c9
cpufreq.c 48.5 KB