linux-kernel - [PATCH 3.14 27/43] cpuidle: remove state_count field from struct cpuidle

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Message-Id: <20150417132557.198588549@linuxfoundation.org>
Date:	Fri, 17 Apr 2015 15:29:01 +0200
From:	Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:	linux-kernel@...r.kernel.org
Cc:	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	stable@...r.kernel.org,
	Thomas Schlichter <thomas.schlichter@....de>,
	Bartlomiej Zolnierkiewicz <b.zolnierkie@...sung.com>,
	Kyungmin Park <kyungmin.park@...sung.com>,
	Daniel Lezcano <daniel.lezcano@...aro.org>,
	"Rafael J. Wysocki" <rafael.j.wysocki@...el.com>
Subject: [PATCH 3.14 27/43] cpuidle: remove state_count field from struct cpuidle_device

3.14-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Bartlomiej Zolnierkiewicz <b.zolnierkie@...sung.com>

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@....de>
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@...sung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@...sung.com>
Acked-by: Daniel Lezcano <daniel.lezcano@...aro.org>
[ rjw: Changelog ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 drivers/cpuidle/cpuidle.c |    3 ---
 drivers/cpuidle/sysfs.c   |    5 +++--
 include/linux/cpuidle.h   |    1 -
 3 files changed, 3 insertions(+), 6 deletions(-)

--- a/drivers/cpuidle/cpuidle.c
+++ b/drivers/cpuidle/cpuidle.c
@@ -252,9 +252,6 @@ int cpuidle_enable_device(struct cpuidle
 	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;
--- a/drivers/cpuidle/sysfs.c
+++ b/drivers/cpuidle/sysfs.c
@@ -398,7 +398,7 @@ static int cpuidle_add_state_sysfs(struc
 	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;
@@ -430,9 +430,10 @@ 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);
 }

--- 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;

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