Commit bff8e60a authored by Rafael J. Wysocki's avatar Rafael J. Wysocki
Browse files

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: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
parent 75a80267

drivers/idle/intel_idle.c

+42 −3
Original line number Diff line number Diff line
@@ -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) {

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