To force wakeup a cpu, we need to compute the timeout in the fast idle
path as a state may be enabled or disabled but there did not exist a
feedback to driver when a state is enabled or disabled.
This patch adds a callback whenever a state_usage records a store for
disable attribute

Signed-off-by: Abhishek Goel <hunt...@linux.vnet.ibm.com>
---
 drivers/cpuidle/sysfs.c | 15 ++++++++++++++-
 include/linux/cpuidle.h |  3 +++
 2 files changed, 17 insertions(+), 1 deletion(-)

diff --git a/drivers/cpuidle/sysfs.c b/drivers/cpuidle/sysfs.c
index 2bb2683b4..6c9bf2f7b 100644
--- a/drivers/cpuidle/sysfs.c
+++ b/drivers/cpuidle/sysfs.c
@@ -418,8 +418,21 @@ static ssize_t cpuidle_state_store(struct kobject *kobj, 
struct attribute *attr,
        struct cpuidle_state_attr *cattr = attr_to_stateattr(attr);
        struct cpuidle_device *dev = kobj_to_device(kobj);
 
-       if (cattr->store)
+       if (cattr->store) {
                ret = cattr->store(state, state_usage, buf, size);
+               if (ret == size &&
+                       strncmp(cattr->attr.name, "disable",
+                                               strlen("disable"))) {
+                       struct kobject *cpuidle_kobj = kobj->parent;
+                       struct cpuidle_device *dev =
+                                       to_cpuidle_device(cpuidle_kobj);
+                       struct cpuidle_driver *drv =
+                                       cpuidle_get_cpu_driver(dev);
+
+                       if (drv->disable_callback)
+                               drv->disable_callback(dev, drv);
+               }
+       }
 
        /* reset poll time cache */
        dev->poll_limit_ns = 0;
diff --git a/include/linux/cpuidle.h b/include/linux/cpuidle.h
index 4b6b5bea8..1729a497b 100644
--- a/include/linux/cpuidle.h
+++ b/include/linux/cpuidle.h
@@ -122,6 +122,9 @@ struct cpuidle_driver {
        /* the driver handles the cpus in cpumask */
        struct cpumask          *cpumask;
 
+       void (*disable_callback)(struct cpuidle_device *dev,
+                                struct cpuidle_driver *drv);
+
        /* preferred governor to switch at register time */
        const char              *governor;
 };
-- 
2.17.1

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