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path: root/drivers/cpuidle/cpuidle.c
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Diffstat (limited to 'drivers/cpuidle/cpuidle.c')
-rw-r--r--drivers/cpuidle/cpuidle.c28
1 files changed, 28 insertions, 0 deletions
diff --git a/drivers/cpuidle/cpuidle.c b/drivers/cpuidle/cpuidle.c
index f7cab5e9c4d6..3e146b2ada4a 100644
--- a/drivers/cpuidle/cpuidle.c
+++ b/drivers/cpuidle/cpuidle.c
@@ -72,6 +72,34 @@ typedef int (*cpuidle_enter_t)(struct cpuidle_device *dev,
72static cpuidle_enter_t cpuidle_enter_ops; 72static cpuidle_enter_t cpuidle_enter_ops;
73 73
74/** 74/**
75 * cpuidle_play_dead - cpu off-lining
76 *
77 * Only returns in case of an error
78 */
79int cpuidle_play_dead(void)
80{
81 struct cpuidle_device *dev = __this_cpu_read(cpuidle_devices);
82 struct cpuidle_driver *drv = cpuidle_get_driver();
83 int i, dead_state = -1;
84 int power_usage = -1;
85
86 /* Find lowest-power state that supports long-term idle */
87 for (i = CPUIDLE_DRIVER_STATE_START; i < drv->state_count; i++) {
88 struct cpuidle_state *s = &drv->states[i];
89
90 if (s->power_usage < power_usage && s->enter_dead) {
91 power_usage = s->power_usage;
92 dead_state = i;
93 }
94 }
95
96 if (dead_state != -1)
97 return drv->states[dead_state].enter_dead(dev, dead_state);
98
99 return -ENODEV;
100}
101
102/**
75 * cpuidle_idle_call - the main idle loop 103 * cpuidle_idle_call - the main idle loop
76 * 104 *
77 * NOTE: no locks or semaphores should be used here 105 * NOTE: no locks or semaphores should be used here