in intel_idle.c [1608:1621]
static void __init intel_idle_cpuidle_driver_init(struct cpuidle_driver *drv)
{
cpuidle_poll_state_init(drv);
if (disabled_states_mask & BIT(0))
drv->states[0].flags |= CPUIDLE_FLAG_OFF;
drv->state_count = 1;
if (icpu)
intel_idle_init_cstates_icpu(drv);
else
intel_idle_init_cstates_acpi(drv);
}