Commit 0394c667 authored by Len Brown's avatar Len Brown
Browse files

intel_idle: delete power_policy modparam, and choose substate functions 



The idea behind power policy was that it would start off as a modparam,
and then hook into the new "global" in-kernel power vs energy tunable.
But that tunable isn't happening, so delete the hook here.

With the policy hook gone, the sub-state choice functions
do not do anything useful, so delete them from the critical path.

To handle sub-states in the future, we will advertise them
with dedicated cpuidle_state entries.  That is necessary
because some of the sub-states will have substantially different
properties than their peer sub-states.

Signed-off-by: default avatarLen Brown <len.brown@intel.com>
parent c4236282

drivers/idle/intel_idle.c

+0 −43
Original line number Diff line number Diff line
@@ -77,10 +77,8 @@ static struct cpuidle_driver intel_idle_driver = { 
};

/* intel_idle.max_cstate=0 disables driver */

static int max_cstate = MWAIT_MAX_NUM_CSTATES - 1;

static int power_policy = 7; /* 0 = max perf; 15 = max powersave */



static unsigned int mwait_substates;

static int (*choose_substate)(int);



/* Reliable LAPIC Timer States, bit 1 for C1 etc.  */

static unsigned int lapic_timer_reliable_states;
@@ -168,42 +166,6 @@ static struct cpuidle_state atom_cstates[MWAIT_MAX_NUM_CSTATES] = { 
		.enter = NULL },	/* disabled */

};



/*

 * choose_tunable_substate()

 *

 * Run-time decision on which C-state substate to invoke

 * If power_policy = 0, choose shallowest substate (0)

 * If power_policy = 15, choose deepest substate

 * If power_policy = middle, choose middle substate etc.

 */

static int choose_tunable_substate(int cstate)

{

	unsigned int num_substates;

	unsigned int substate_choice;



	power_policy &= 0xF;	/* valid range: 0-15 */

	cstate &= 7;	/* valid range: 0-7 */



	num_substates = (mwait_substates >> ((cstate) * 4))

				& MWAIT_SUBSTATE_MASK;



	if (num_substates <= 1)

		return 0;



	substate_choice = ((power_policy + (power_policy + 1) *

				(num_substates - 1)) / 16);



	return substate_choice;

}



/*

 * choose_zero_substate()

 */

static int choose_zero_substate(int cstate)

{

	return 0;

}



/**

 * intel_idle

 * @dev: cpuidle_device
@@ -221,8 +183,6 @@ static int intel_idle(struct cpuidle_device *dev, struct cpuidle_state *state) 


	cstate = (((eax) >> MWAIT_SUBSTATE_SIZE) & MWAIT_CSTATE_MASK) + 1;



	eax = eax + (choose_substate)(cstate);



	local_irq_disable();



	if (!(lapic_timer_reliable_states & (1 << (cstate))))
@@ -301,13 +261,11 @@ static int intel_idle_probe(void) 
	case 0x25:	/* Westmere */

	case 0x2C:	/* Westmere */

		cpuidle_state_table = nehalem_cstates;

		choose_substate = choose_tunable_substate;

		break;



	case 0x1C:	/* 28 - Atom Processor */

		lapic_timer_reliable_states = (1 << 2) | (1 << 1); /* C2, C1 */

		cpuidle_state_table = atom_cstates;

		choose_substate = choose_zero_substate;

		break;

#ifdef FUTURE_USE

	case 0x17:	/* 23 - Core 2 Duo */
@@ -447,7 +405,6 @@ static void __exit intel_idle_exit(void) 
module_init(intel_idle_init);

module_exit(intel_idle_exit);



module_param(power_policy, int, 0644);

module_param(max_cstate, int, 0444);



MODULE_AUTHOR("Len Brown <len.brown@intel.com>");

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