cpuidle: remove state_count field from struct cpuidle_device

Thomas Schlichter reports the following issue on his Samsung NC20:

"The C-states C1 and C2 to the OS when connected to AC, and additionally
 provides the C3 C-state when disconnected from AC.  However, the number
 of C-states shown in sysfs is fixed to the number of C-states present
 at boot.
   If I boot with AC connected, I always only see the C-states up to C2
   even if I disconnect AC.

   The reason is commit 130a5f692425 (ACPI / cpuidle: remove dev->state_count
   setting).  It removes the update of dev->state_count, but sysfs uses
   exactly this variable to show the C-states.

   The fix is to use drv->state_count in sysfs.  As this is currently the
   last user of dev->state_count, this variable can be completely removed."

Remove dev->state_count as per the above.

Reported-by: Thomas Schlichter <thomas.schlichter@web.de>
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Acked-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Cc: 3.14+ <stable@vger.kernel.org> # 3.14+
[ rjw: Changelog ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

3 files changed, 3 insertions, 6 deletions

diff --git a/drivers/cpuidle/cpuidle.c b/drivers/cpuidle/cpuidle.c
index 080bd2dbde4b..7a73a279e179 100644
--- a/drivers/cpuidle/cpuidle.c
+++ b/drivers/cpuidle/cpuidle.c
@@ -330,9 +330,6 @@ int cpuidle_enable_device(struct cpuidle_device *dev)
         if (!dev->registered)
                 return -EINVAL;
 
-        if (!dev->state_count)
-                dev->state_count = drv->state_count;
-
         ret = cpuidle_add_device_sysfs(dev);
         if (ret)
                 return ret;
diff --git a/drivers/cpuidle/sysfs.c b/drivers/cpuidle/sysfs.c
index 97c5903b4606..832a2c3f01ff 100644
--- a/drivers/cpuidle/sysfs.c
+++ b/drivers/cpuidle/sysfs.c
@@ -401,7 +401,7 @@ static int cpuidle_add_state_sysfs(struct cpuidle_device *device)
         struct cpuidle_driver *drv = cpuidle_get_cpu_driver(device);
 
         /* state statistics */
-        for (i = 0; i < device->state_count; i++) {
+        for (i = 0; i < drv->state_count; i++) {
                 kobj = kzalloc(sizeof(struct cpuidle_state_kobj), GFP_KERNEL);
                 if (!kobj)
                         goto error_state;
@@ -433,9 +433,10 @@ error_state:
  */
 static void cpuidle_remove_state_sysfs(struct cpuidle_device *device)
 {
+        struct cpuidle_driver *drv = cpuidle_get_cpu_driver(device);
         int i;
 
-        for (i = 0; i < device->state_count; i++)
+        for (i = 0; i < drv->state_count; i++)
                 cpuidle_free_state_kobj(device, i);
 }
 
diff --git a/include/linux/cpuidle.h b/include/linux/cpuidle.h
index 306178d7309f..9c5e89254796 100644
--- a/include/linux/cpuidle.h
+++ b/include/linux/cpuidle.h
@@ -77,7 +77,6 @@ struct cpuidle_device {
         unsigned int            cpu;
 
         int                     last_residency;
-        int                     state_count;
         struct cpuidle_state_usage      states_usage[CPUIDLE_STATE_MAX];
         struct cpuidle_state_kobj *kobjs[CPUIDLE_STATE_MAX];
         struct cpuidle_driver_kobj *kobj_driver;