From bff8e60a86f4960133f90ad9add9adeb082b8154 Mon Sep 17 00:00:00 2001 From: "Rafael J. Wysocki" Date: Fri, 13 Dec 2019 09:56:21 +0100 Subject: intel_idle: Allow ACPI _CST to be used for selected known processors Update the intel_idle driver to get the C-states information from ACPI _CST in some cases in which the processor is known to the driver, as long as that information is available and the new use_acpi flag is set in the profile of the processor in question. In the cases when there is a specific table of C-states for the given processor in the driver, that table is used as the primary source of information on the available C-states, but if ACPI _CST is present, the C-states that are not listed by it will not be enabled by default (they still can be enabled later by user space via sysfs, though). The new CPUIDLE_FLAG_ALWAYS_ENABLE flag can be used for marking C-states that should be enabled by default even if they are not listed by ACPI _CST. Signed-off-by: Rafael J. Wysocki --- drivers/idle/intel_idle.c | 45 ++++++++++++++++++++++++++++++++++++++++++--- 1 file changed, 42 insertions(+), 3 deletions(-) (limited to 'drivers/idle') diff --git a/drivers/idle/intel_idle.c b/drivers/idle/intel_idle.c index 28812d93d59a..a072b84d9595 100644 --- a/drivers/idle/intel_idle.c +++ b/drivers/idle/intel_idle.c @@ -80,6 +80,7 @@ struct idle_cpu { unsigned long auto_demotion_disable_flags; bool byt_auto_demotion_disable_flag; bool disable_promotion_to_c1e; + bool use_acpi; }; static const struct idle_cpu *icpu; @@ -90,6 +91,11 @@ static void intel_idle_s2idle(struct cpuidle_device *dev, struct cpuidle_driver *drv, int index); static struct cpuidle_state *cpuidle_state_table; +/* + * Enable this state by default even if the ACPI _CST does not list it. + */ +#define CPUIDLE_FLAG_ALWAYS_ENABLE BIT(15) + /* * Set this flag for states where the HW flushes the TLB for us * and so we don't need cross-calls to keep it consistent. @@ -1230,9 +1236,33 @@ static void intel_idle_init_cstates_acpi(struct cpuidle_driver *drv) state->enter_s2idle = intel_idle_s2idle; } } + +static bool intel_idle_off_by_default(u32 mwait_hint) +{ + int cstate, limit; + + /* + * If there are no _CST C-states, do not disable any C-states by + * default. + */ + if (!acpi_state_table.count) + return false; + + limit = min_t(int, CPUIDLE_STATE_MAX, acpi_state_table.count); + /* + * If limit > 0, intel_idle_cst_usable() has returned 'true', so all of + * the interesting states are ACPI_CSTATE_FFH. + */ + for (cstate = 1; cstate < limit; cstate++) { + if (acpi_state_table.states[cstate].address == mwait_hint) + return false; + } + return true; +} #else /* !CONFIG_ACPI_PROCESSOR_CSTATE */ static inline bool intel_idle_acpi_cst_extract(void) { return false; } static inline void intel_idle_init_cstates_acpi(struct cpuidle_driver *drv) { } +static inline bool intel_idle_off_by_default(u32 mwait_hint) { return false; } #endif /* !CONFIG_ACPI_PROCESSOR_CSTATE */ /* @@ -1273,10 +1303,13 @@ static int __init intel_idle_probe(void) pr_debug("MWAIT substates: 0x%x\n", mwait_substates); icpu = (const struct idle_cpu *)id->driver_data; - if (icpu) + if (icpu) { cpuidle_state_table = icpu->state_table; - else if (!intel_idle_acpi_cst_extract()) + if (icpu->use_acpi) + intel_idle_acpi_cst_extract(); + } else if (!intel_idle_acpi_cst_extract()) { return -ENODEV; + } pr_debug("v" INTEL_IDLE_VERSION " model 0x%X\n", boot_cpu_data.x86_model); @@ -1484,7 +1517,13 @@ static void intel_idle_init_cstates_icpu(struct cpuidle_driver *drv) continue; /* Structure copy. */ - drv->states[drv->state_count++] = cpuidle_state_table[cstate]; + drv->states[drv->state_count] = cpuidle_state_table[cstate]; + + if (icpu->use_acpi && intel_idle_off_by_default(mwait_hint) && + !(cpuidle_state_table[cstate].flags & CPUIDLE_FLAG_ALWAYS_ENABLE)) + drv->states[drv->state_count].flags |= CPUIDLE_FLAG_OFF; + + drv->state_count++; } if (icpu->byt_auto_demotion_disable_flag) { -- cgit v1.2.3