[3.16.y-ckt stable] Patch "cpuidle: remove state_count field from struct cpuidle_device" has been added to staging queue

[Luis Henriques]

This is a note to let you know that I have just added a patch titled

    cpuidle: remove state_count field from struct cpuidle_device

to the linux-3.16.y-queue branch of the 3.16.y-ckt extended stable tree 
which can be found at:

    http://kernel.ubuntu.com/git/ubuntu/linux.git/log/?h=linux-3.16.y-queue

This patch is scheduled to be released in version 3.16.7-ckt11.

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.16.y-ckt tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Luis

------

>From 0a9a94ed622a67fa49e44c3187fd74c5f379405a Mon Sep 17 00:00:00 2001
From: Bartlomiej Zolnierkiewicz <b.zolnierkie at samsung.com>
Date: Tue, 31 Mar 2015 20:15:09 +0200
Subject: cpuidle: remove state_count field from struct cpuidle_device

commit d75e4af14e228bbe3f86e29bcecb8e6be98d4e04 upstream.

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 at web.de>
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie at samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park at samsung.com>
Acked-by: Daniel Lezcano <daniel.lezcano at linaro.org>
[ rjw: Changelog ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki at intel.com>
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 drivers/cpuidle/cpuidle.c | 3 ---
 drivers/cpuidle/sysfs.c   | 5 +++--
 include/linux/cpuidle.h   | 1 -
 3 files changed, 3 insertions(+), 6 deletions(-)

diff --git a/drivers/cpuidle/cpuidle.c b/drivers/cpuidle/cpuidle.c
index cb7019977c50..d3185606473a 100644
--- a/drivers/cpuidle/cpuidle.c
+++ b/drivers/cpuidle/cpuidle.c
@@ -289,9 +289,6 @@ 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 efe2f175168f..3368c50ef0ea 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 25e0df6155a4..575b7166cb08 100644
--- a/include/linux/cpuidle.h
+++ b/include/linux/cpuidle.h
@@ -69,7 +69,6 @@ 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;