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>
diff --git a/drivers/acpi/processor_idle.c b/drivers/acpi/processor_idle.c
index 2dd2c1f..556ee15 100644
--- a/drivers/acpi/processor_idle.c
+++ b/drivers/acpi/processor_idle.c
@@ -1669,6 +1669,7 @@
return -EINVAL;
}
+ dev->cpu = pr->id;
for (i = 0; i < CPUIDLE_STATE_MAX; i++) {
dev->states[i].name[0] = '\0';
dev->states[i].desc[0] = '\0';
@@ -1738,7 +1739,7 @@
int acpi_processor_cst_has_changed(struct acpi_processor *pr)
{
- int ret;
+ int ret = 0;
if (boot_option_idle_override)
return 0;
@@ -1756,8 +1757,10 @@
cpuidle_pause_and_lock();
cpuidle_disable_device(&pr->power.dev);
acpi_processor_get_power_info(pr);
- acpi_processor_setup_cpuidle(pr);
- ret = cpuidle_enable_device(&pr->power.dev);
+ if (pr->flags.power) {
+ acpi_processor_setup_cpuidle(pr);
+ ret = cpuidle_enable_device(&pr->power.dev);
+ }
cpuidle_resume_and_unlock();
return ret;
@@ -1813,7 +1816,6 @@
if (pr->flags.power) {
#ifdef CONFIG_CPU_IDLE
acpi_processor_setup_cpuidle(pr);
- pr->power.dev.cpu = pr->id;
if (cpuidle_register_device(&pr->power.dev))
return -EIO;
#endif
@@ -1850,8 +1852,7 @@
return 0;
#ifdef CONFIG_CPU_IDLE
- if (pr->flags.power)
- cpuidle_unregister_device(&pr->power.dev);
+ cpuidle_unregister_device(&pr->power.dev);
#endif
pr->flags.power_setup_done = 0;
diff --git a/drivers/cpuidle/cpuidle.c b/drivers/cpuidle/cpuidle.c
index fc555a9..23554b6 100644
--- a/drivers/cpuidle/cpuidle.c
+++ b/drivers/cpuidle/cpuidle.c
@@ -38,6 +38,8 @@
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 @@
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 @@
#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 @@
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 @@
{
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);