Merge tag 'pm+acpi-3.12-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm

Pull ACPI and power management updates from Rafael Wysocki:

 1) ACPI-based PCI hotplug (ACPIPHP) subsystem rework and introduction
    of Intel Thunderbolt support on systems that use ACPI for signalling
    Thunderbolt hotplug events.  This also should make ACPIPHP work in
    some cases in which it was known to have problems.  From
    Rafael J Wysocki, Mika Westerberg and Kirill A Shutemov.

 2) ACPI core code cleanups and dock station support cleanups from
    Jiang Liu and Rafael J Wysocki.

 3) Fixes for locking problems related to ACPI device hotplug from
    Rafael J Wysocki.

 4) ACPICA update to version 20130725 includig fixes, cleanups, support
    for more than 256 GPEs per GPE block and a change to make the ACPI
    PM Timer optional (we've seen systems without the PM Timer in the
    field already).  One of the fixes, related to the DeRefOf operator,
    is necessary to prevent some Windows 8 oriented AML from causing
    problems to happen.  From Bob Moore, Lv Zheng, and Jung-uk Kim.

 5) Removal of the old and long deprecated /proc/acpi/event interface
    and related driver changes from Thomas Renninger.

 6) ACPI and Xen changes to make the reduced hardware sleep work with
    the latter from Ben Guthro.

 7) ACPI video driver cleanups and a blacklist of systems that should
    not tell the BIOS that they are compatible with Windows 8 (or ACPI
    backlight and possibly other things will not work on them).  From
    Felipe Contreras.

 8) Assorted ACPI fixes and cleanups from Aaron Lu, Hanjun Guo,
    Kuppuswamy Sathyanarayanan, Lan Tianyu, Sachin Kamat, Tang Chen,
    Toshi Kani, and Wei Yongjun.

 9) cpufreq ondemand governor target frequency selection change to
    reduce oscillations between min and max frequencies (essentially,
    it causes the governor to choose target frequencies proportional
    to load) from Stratos Karafotis.

10) cpufreq fixes allowing sysfs attributes file permissions to be
    preserved over suspend/resume cycles Srivatsa S Bhat.

11) Removal of Device Tree parsing for CPU device nodes from multiple
    cpufreq drivers that required some changes related to
    of_get_cpu_node() to be made in a few architectures and in the
    driver core.  From Sudeep KarkadaNagesha.

12) cpufreq core fixes and cleanups related to mutual exclusion and
    driver module references from Viresh Kumar, Lukasz Majewski and
    Rafael J Wysocki.

13) Assorted cpufreq fixes and cleanups from Amit Daniel Kachhap,
    Bartlomiej Zolnierkiewicz, Hanjun Guo, Jingoo Han, Joseph Lo,
    Julia Lawall, Li Zhong, Mark Brown, Sascha Hauer, Stephen Boyd,
    Stratos Karafotis, and Viresh Kumar.

14) Fixes to prevent race conditions in coupled cpuidle from happening
    from Colin Cross.

15) cpuidle core fixes and cleanups from Daniel Lezcano and
    Tuukka Tikkanen.

16) Assorted cpuidle fixes and cleanups from Daniel Lezcano,
    Geert Uytterhoeven, Jingoo Han, Julia Lawall, Linus Walleij,
    and Sahara.

17) System sleep tracing changes from Todd E Brandt and Shuah Khan.

18) PNP subsystem conversion to using struct dev_pm_ops for power
    management from Shuah Khan.

* tag 'pm+acpi-3.12-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: (217 commits)
  cpufreq: Don't use smp_processor_id() in preemptible context
  cpuidle: coupled: fix race condition between pokes and safe state
  cpuidle: coupled: abort idle if pokes are pending
  cpuidle: coupled: disable interrupts after entering safe state
  ACPI / hotplug: Remove containers synchronously
  driver core / ACPI: Avoid device hot remove locking issues
  cpufreq: governor: Fix typos in comments
  cpufreq: governors: Remove duplicate check of target freq in supported range
  cpufreq: Fix timer/workqueue corruption due to double queueing
  ACPI / EC: Add ASUSTEK L4R to quirk list in order to validate ECDT
  ACPI / thermal: Add check of "_TZD" availability and evaluating result
  cpufreq: imx6q: Fix clock enable balance
  ACPI: blacklist win8 OSI for buggy laptops
  cpufreq: tegra: fix the wrong clock name
  cpuidle: Change struct menu_device field types
  cpuidle: Add a comment warning about possible overflow
  cpuidle: Fix variable domains in get_typical_interval()
  cpuidle: Fix menu_device->intervals type
  cpuidle: CodingStyle: Break up multiple assignments on single line
  cpuidle: Check called function parameter in get_typical_interval()
  ...

1 files changed, 28 insertions, 15 deletions

diff --git a/drivers/base/core.c b/drivers/base/core.c
index c7b0925..c7cfadc 100644
--- a/drivers/base/core.c
+++ b/drivers/base/core.c
@@ -50,6 +50,28 @@ static struct kobject *dev_kobj;
 struct kobject *sysfs_dev_char_kobj;
 struct kobject *sysfs_dev_block_kobj;
 
+static DEFINE_MUTEX(device_hotplug_lock);
+
+void lock_device_hotplug(void)
+{
+	mutex_lock(&device_hotplug_lock);
+}
+
+void unlock_device_hotplug(void)
+{
+	mutex_unlock(&device_hotplug_lock);
+}
+
+int lock_device_hotplug_sysfs(void)
+{
+	if (mutex_trylock(&device_hotplug_lock))
+		return 0;
+
+	/* Avoid busy looping (5 ms of sleep should do). */
+	msleep(5);
+	return restart_syscall();
+}
+
 #ifdef CONFIG_BLOCK
 static inline int device_is_not_partition(struct device *dev)
 {
@@ -407,9 +429,9 @@ static ssize_t online_show(struct device *dev, struct device_attribute *attr,
 {
 	bool val;
 
-	lock_device_hotplug();
+	device_lock(dev);
 	val = !dev->offline;
-	unlock_device_hotplug();
+	device_unlock(dev);
 	return sprintf(buf, "%u\n", val);
 }
 
@@ -423,7 +445,10 @@ static ssize_t online_store(struct device *dev, struct device_attribute *attr,
 	if (ret < 0)
 		return ret;
 
-	lock_device_hotplug();
+	ret = lock_device_hotplug_sysfs();
+	if (ret)
+		return ret;
+
 	ret = val ? device_online(dev) : device_offline(dev);
 	unlock_device_hotplug();
 	return ret < 0 ? ret : count;
@@ -1450,18 +1475,6 @@ int __init devices_init(void)
 	return -ENOMEM;
 }
 
-static DEFINE_MUTEX(device_hotplug_lock);
-
-void lock_device_hotplug(void)
-{
-	mutex_lock(&device_hotplug_lock);
-}
-
-void unlock_device_hotplug(void)
-{
-	mutex_unlock(&device_hotplug_lock);
-}
-
 static int device_check_offline(struct device *dev, void *not_used)
 {
 	int ret;