When cpuidle drivers do not supply explicit power_usage values,
cpuidle/driver.c inserts dummy values instead. When a running processor
dynamically gains new C-states (e.g. after ACPI events), the power_usage
values of those states will stay uninitialized, and cpuidle governors
will never choose to enter them.
This patch moves the dummy value initialization from
cpuidle_register_driver to cpuidle_enable_device, which drivers such as
acpi/processor_idle.c will call again when they add or remove C-states.
Tested and verified on an Acer AC700 Chromebook, which supports the C3
state only when it switches from AC to battery power.
Signed-off-by: Julius Werner <jwer...@chromium.org>
---
drivers/cpuidle/cpuidle.c | 24 ++++++++++++++++++++++++
drivers/cpuidle/driver.c | 25 -------------------------
2 files changed, 24 insertions(+), 25 deletions(-)
diff --git a/drivers/cpuidle/cpuidle.c b/drivers/cpuidle/cpuidle.c
index 7f15b85..bef3a31 100644
--- a/drivers/cpuidle/cpuidle.c
+++ b/drivers/cpuidle/cpuidle.c
@@ -298,6 +298,28 @@ static void poll_idle_init(struct cpuidle_driver *drv)
static void poll_idle_init(struct cpuidle_driver *drv) {}
#endif /* CONFIG_ARCH_HAS_CPU_RELAX */
+static void set_power_states(struct cpuidle_driver *drv)
+{
+ int i;
+
+ /*
+ * cpuidle driver should set the drv->power_specified bit
+ * before registering if the driver provides
+ * power_usage numbers.
+ *
+ * If power_specified is not set,
+ * we fill in power_usage with decreasing values as the
+ * cpuidle code has an implicit assumption that state Cn
+ * uses less power than C(n-1).
+ *
+ * With CONFIG_ARCH_HAS_CPU_RELAX, C0 is already assigned
+ * an power value of -1. So we use -2, -3, etc, for other
+ * c-states.
+ */
+ for (i = CPUIDLE_DRIVER_STATE_START; i < drv->state_count; i++)
+ drv->states[i].power_usage = -1 - i;
+}
+
/**
* cpuidle_enable_device - enables idle PM for a CPU
* @dev: the CPU
@@ -330,6 +352,8 @@ int cpuidle_enable_device(struct cpuidle_device *dev)
cpuidle_enter_tk : cpuidle_enter;
poll_idle_init(drv);
+ if (!drv->power_specified)
+ set_power_states(drv);
if ((ret = cpuidle_add_state_sysfs(dev)))
return ret;
diff --git a/drivers/cpuidle/driver.c b/drivers/cpuidle/driver.c
index 87db387..caaed27 100644
--- a/drivers/cpuidle/driver.c
+++ b/drivers/cpuidle/driver.c
@@ -18,28 +18,6 @@ static struct cpuidle_driver *cpuidle_curr_driver;
DEFINE_SPINLOCK(cpuidle_driver_lock);
int cpuidle_driver_refcount;
-static void set_power_states(struct cpuidle_driver *drv)
-{
- int i;
-
- /*
- * cpuidle driver should set the drv->power_specified bit
- * before registering if the driver provides
- * power_usage numbers.
- *
- * If power_specified is not set,
- * we fill in power_usage with decreasing values as the
- * cpuidle code has an implicit assumption that state Cn
- * uses less power than C(n-1).
- *
- * With CONFIG_ARCH_HAS_CPU_RELAX, C0 is already assigned
- * an power value of -1. So we use -2, -3, etc, for other
- * c-states.
- */
- for (i = CPUIDLE_DRIVER_STATE_START; i < drv->state_count; i++)
- drv->states[i].power_usage = -1 - i;
-}
-
/**
* cpuidle_register_driver - registers a driver
* @drv: the driver
@@ -58,9 +36,6 @@ int cpuidle_register_driver(struct cpuidle_driver *drv)
return -EBUSY;
}
- if (!drv->power_specified)
- set_power_states(drv);
-
cpuidle_curr_driver = drv;
spin_unlock(&cpuidle_driver_lock);
--
1.7.8.6
--
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