• Rafael J. Wysocki's avatar
    cpufreq: intel_pstate: Request P-states control from SMM if needed · d0ea59e1
    Rafael J. Wysocki authored
    Currently, intel_pstate is unable to control P-states on my
    IvyBridge-based Acer Aspire S5, because they are controlled by SMM
    on that machine by default and it is necessary to request OS control
    of P-states from it via the SMI Command register exposed in the ACPI
    FADT.  intel_pstate doesn't do that now, but acpi-cpufreq and other
    cpufreq drivers for x86 platforms do.
    Address this problem by making intel_pstate use the ACPI-defined
    mechanism as well.  However, intel_pstate is not modular and it
    doesn't need the module refcount tricks played by
    acpi_processor_notify_smm(), so export the core of this function
    to it as acpi_processor_pstate_control() and make it call that.
    [The changes in processor_perflib.c related to this should not
    make any functional difference for the acpi_processor_notify_smm()
    To be safe, only call acpi_processor_notify_smm() from intel_pstate
    if ACPI _PPC support is enabled in it.
    Suggested-by: default avatarSrinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
    Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
    Acked-by: default avatarSrinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
processor.h 10.9 KB