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cpuidle acpi driver: fix oops on AC<->DC

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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>
This commit is contained in:
Venkatesh Pallipadi 2008-05-19 19:09:27 -04:00 committed by Len Brown
parent e1094bfa26
commit dcb84f335b
3 changed files with 43 additions and 11 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

13
drivers/acpi/processor_idle.c
View file

@ -1669,6 +1669,7 @@ static int acpi_processor_setup_cpuidle(struct acpi_processor *pr)
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 @@ static int acpi_processor_setup_cpuidle(struct acpi_processor *pr)
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 @@ int acpi_processor_cst_has_changed(struct acpi_processor *pr)
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 @@ int __cpuinit acpi_processor_power_init(struct acpi_processor *pr,
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 @@ int acpi_processor_power_exit(struct acpi_processor *pr,
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;

40
drivers/cpuidle/cpuidle.c
View file

@ -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);

1
include/linux/cpuidle.h
View file

@ -82,6 +82,7 @@ struct cpuidle_state_kobj {
};
struct cpuidle_device {
unsigned int registered:1;
unsigned int enabled:1;
unsigned int cpu;