intel_idle: delete power_policy modparam, and choose substate functions
Len Brown [Fri, 23 Jul 2010 20:04:46 +0000 (16:04 -0400)]
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: Len Brown <len.brown@intel.com>

drivers/idle/intel_idle.c

index 82c9a58..6d43bc3 100755 (executable)
@@ -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>");