From d0ea59e188941417a9fb5898d894b3106a8ad313 Mon Sep 17 00:00:00 2001 From: "Rafael J. Wysocki" Date: Thu, 17 Nov 2016 22:47:47 +0100 Subject: [PATCH] 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/acpi/processor_perflib.c | 45 ++++++++++++++++++++------------ drivers/cpufreq/intel_pstate.c | 13 +++++++++ include/acpi/processor.h | 1 + 3 files changed, 42 insertions(+), 17 deletions(-) diff --git a/drivers/acpi/processor_perflib.c b/drivers/acpi/processor_perflib.c index bb01dea39fdc..9c67faa034b5 100644 --- a/drivers/acpi/processor_perflib.c +++ b/drivers/acpi/processor_perflib.c @@ -465,11 +465,33 @@ int acpi_processor_get_performance_info(struct acpi_processor *pr) return result; } EXPORT_SYMBOL_GPL(acpi_processor_get_performance_info); -int acpi_processor_notify_smm(struct module *calling_module) + +int acpi_processor_pstate_control(void) { acpi_status status; - static int is_done = 0; + if (!acpi_gbl_FADT.smi_command || !acpi_gbl_FADT.pstate_control) + return 0; + + ACPI_DEBUG_PRINT((ACPI_DB_INFO, + "Writing pstate_control [0x%x] to smi_command [0x%x]\n", + acpi_gbl_FADT.pstate_control, acpi_gbl_FADT.smi_command)); + + status = acpi_os_write_port(acpi_gbl_FADT.smi_command, + (u32)acpi_gbl_FADT.pstate_control, 8); + if (ACPI_SUCCESS(status)) + return 1; + + ACPI_EXCEPTION((AE_INFO, status, + "Failed to write pstate_control [0x%x] to smi_command [0x%x]", + acpi_gbl_FADT.pstate_control, acpi_gbl_FADT.smi_command)); + return -EIO; +} + +int acpi_processor_notify_smm(struct module *calling_module) +{ + static int is_done = 0; + int result; if (!(acpi_processor_ppc_status & PPC_REGISTERED)) return -EBUSY; @@ -492,26 +514,15 @@ int acpi_processor_notify_smm(struct module *calling_module) is_done = -EIO; - /* Can't write pstate_control to smi_command if either value is zero */ - if ((!acpi_gbl_FADT.smi_command) || (!acpi_gbl_FADT.pstate_control)) { + result = acpi_processor_pstate_control(); + if (!result) { ACPI_DEBUG_PRINT((ACPI_DB_INFO, "No SMI port or pstate_control\n")); module_put(calling_module); return 0; } - - ACPI_DEBUG_PRINT((ACPI_DB_INFO, - "Writing pstate_control [0x%x] to smi_command [0x%x]\n", - acpi_gbl_FADT.pstate_control, acpi_gbl_FADT.smi_command)); - - status = acpi_os_write_port(acpi_gbl_FADT.smi_command, - (u32) acpi_gbl_FADT.pstate_control, 8); - if (ACPI_FAILURE(status)) { - ACPI_EXCEPTION((AE_INFO, status, - "Failed to write pstate_control [0x%x] to " - "smi_command [0x%x]", acpi_gbl_FADT.pstate_control, - acpi_gbl_FADT.smi_command)); + if (result < 0) { module_put(calling_module); - return status; + return result; } /* Success. If there's no _PPC, we need to fear nothing, so 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; diff --git a/include/acpi/processor.h b/include/acpi/processor.h index f3db11c24654..dd0cb04046ce 100644 --- a/include/acpi/processor.h +++ b/include/acpi/processor.h @@ -249,6 +249,7 @@ extern int acpi_processor_register_performance(struct acpi_processor_performance *performance, unsigned int cpu); extern void acpi_processor_unregister_performance(unsigned int cpu); +int acpi_processor_pstate_control(void); /* note: this locks both the calling module and the processor module if a _PPC object exists, rmmod is disallowed then */ int acpi_processor_notify_smm(struct module *calling_module); -- 2.20.1