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authorVenkatesh Pallipadi <venkatesh.pallipadi@intel.com>2008-05-20 03:09:27 +0400
committerLen Brown <len.brown@intel.com>2008-06-12 03:13:45 +0400
commitdcb84f335bee9c9a7781cfc5d74492dccaf066d2 (patch)
treee24d4ca7df49b2a87862aa69c09d21ad45a024b7 /drivers/cpuidle
parente1094bfa26e5e94af2fea79e004614dbce42b008 (diff)
downloadlinux-dcb84f335bee9c9a7781cfc5d74492dccaf066d2.tar.xz
cpuidle acpi driver: fix oops on AC<->DC
cpuidle and acpi driver interaction bug with the way cpuidle_register_driver() is called. Due to this bug, there will be oops on AC<->DC on some systems, where they support C-states in one DC and not in AC. The current code does ON BOOT: Look at CST and other C-state info to see whether more than C1 is supported. If it is, then acpi processor_idle does a cpuidle_register_driver() call, which internally enables the device. ON CST change notification (AC<->DC) and on suspend-resume: acpi driver temporarily disables device, updates the device with any new C-states, and reenables the device. The problem is is on boot, there are no C2, C3 states supported and we skip the register. Later on AC<->DC, we may get a CST notification and we try to reevaluate CST and enabled the device, without actually registering it. This causes breakage as we try to create /sys fs sub directory, without the parent directory which is created at register time. Thanks to Sanjeev for reporting the problem here. http://bugzilla.kernel.org/show_bug.cgi?id=10394 Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Signed-off-by: Len Brown <len.brown@intel.com>
Diffstat (limited to 'drivers/cpuidle')
-rw-r--r--drivers/cpuidle/cpuidle.c40
1 files changed, 35 insertions, 5 deletions
diff --git a/drivers/cpuidle/cpuidle.c b/drivers/cpuidle/cpuidle.c
index fc555a90bb21..23554b676d6e 100644
--- a/drivers/cpuidle/cpuidle.c
+++ b/drivers/cpuidle/cpuidle.c
@@ -38,6 +38,8 @@ static void cpuidle_kick_cpus(void)
static void cpuidle_kick_cpus(void) {}
#endif
+static int __cpuidle_register_device(struct cpuidle_device *dev);
+
/**
* cpuidle_idle_call - the main idle loop
*
@@ -138,6 +140,12 @@ int cpuidle_enable_device(struct cpuidle_device *dev)
if (!dev->state_count)
return -EINVAL;
+ if (dev->registered == 0) {
+ ret = __cpuidle_register_device(dev);
+ if (ret)
+ return ret;
+ }
+
if ((ret = cpuidle_add_state_sysfs(dev)))
return ret;
@@ -232,10 +240,13 @@ static void poll_idle_init(struct cpuidle_device *dev) {}
#endif /* CONFIG_ARCH_HAS_CPU_RELAX */
/**
- * cpuidle_register_device - registers a CPU's idle PM feature
+ * __cpuidle_register_device - internal register function called before register
+ * and enable routines
* @dev: the cpu
+ *
+ * cpuidle_lock mutex must be held before this is called
*/
-int cpuidle_register_device(struct cpuidle_device *dev)
+static int __cpuidle_register_device(struct cpuidle_device *dev)
{
int ret;
struct sys_device *sys_dev = get_cpu_sysdev((unsigned long)dev->cpu);
@@ -247,18 +258,34 @@ int cpuidle_register_device(struct cpuidle_device *dev)
init_completion(&dev->kobj_unregister);
- mutex_lock(&cpuidle_lock);
-
poll_idle_init(dev);
per_cpu(cpuidle_devices, dev->cpu) = dev;
list_add(&dev->device_list, &cpuidle_detected_devices);
if ((ret = cpuidle_add_sysfs(sys_dev))) {
- mutex_unlock(&cpuidle_lock);
module_put(cpuidle_curr_driver->owner);
return ret;
}
+ dev->registered = 1;
+ return 0;
+}
+
+/**
+ * cpuidle_register_device - registers a CPU's idle PM feature
+ * @dev: the cpu
+ */
+int cpuidle_register_device(struct cpuidle_device *dev)
+{
+ int ret;
+
+ mutex_lock(&cpuidle_lock);
+
+ if ((ret = __cpuidle_register_device(dev))) {
+ mutex_unlock(&cpuidle_lock);
+ return ret;
+ }
+
cpuidle_enable_device(dev);
cpuidle_install_idle_handler();
@@ -278,6 +305,9 @@ void cpuidle_unregister_device(struct cpuidle_device *dev)
{
struct sys_device *sys_dev = get_cpu_sysdev((unsigned long)dev->cpu);
+ if (dev->registered == 0)
+ return;
+
cpuidle_pause_and_lock();
cpuidle_disable_device(dev);