From d0ea59e188941417a9fb5898d894b3106a8ad313 Mon Sep 17 00:00:00 2001 From: "Rafael J. Wysocki" Date: Thu, 17 Nov 2016 22:47:47 +0100 Subject: cpufreq: intel_pstate: Request P-states control from SMM if needed 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() users]. To be safe, only call acpi_processor_notify_smm() from intel_pstate if ACPI _PPC support is enabled in it. Suggested-by: Srinivas Pandruvada Signed-off-by: Rafael J. Wysocki Acked-by: Srinivas Pandruvada --- drivers/cpufreq/intel_pstate.c | 13 +++++++++++++ 1 file changed, 13 insertions(+) (limited to 'drivers/cpufreq') diff --git a/drivers/cpufreq/intel_pstate.c b/drivers/cpufreq/intel_pstate.c index f07e591c0e1f..ec1664bf6ef0 100644 --- a/drivers/cpufreq/intel_pstate.c +++ b/drivers/cpufreq/intel_pstate.c @@ -1909,9 +1909,20 @@ static bool __init intel_pstate_platform_pwr_mgmt_exists(void) return false; } + +static void intel_pstate_request_control_from_smm(void) +{ + /* + * It may be unsafe to request P-states control from SMM if _PPC support + * has not been enabled. + */ + if (acpi_ppc) + acpi_processor_pstate_control(); +} #else /* CONFIG_ACPI not enabled */ static inline bool intel_pstate_platform_pwr_mgmt_exists(void) { return false; } static inline bool intel_pstate_has_acpi_ppc(void) { return false; } +static inline void intel_pstate_request_control_from_smm(void) {} #endif /* CONFIG_ACPI */ static const struct x86_cpu_id hwp_support_ids[] __initconst = { @@ -1963,6 +1974,8 @@ hwp_cpu_matched: if (!hwp_active && hwp_only) goto out; + intel_pstate_request_control_from_smm(); + rc = cpufreq_register_driver(&intel_pstate_driver); if (rc) goto out; -- cgit v1.2.3