Re: CPU_IDLE prevents resuming from STR [was: Re: 2.6.21-rc6-mm1]

Shaohua Li
2007-04-17T06:50:57Z

On Mon, 2007-04-16 at 22:50 -0400, Joshua Wise wrote:
> On Mon, 16 Apr 2007, Shaohua Li wrote:
> > On Sat, 2007-04-14 at 01:45 +0200, Mattia Dongili wrote:
> >> ...
> > please check if the patch at
> > http://marc.info/?l=linux-acpi&m=117523651630038&w=2 fixed the issue
>
> I have the same system as Mattia, and when I applied this patch and turned
> CPU_IDLE back on, I got a panic on boot. Unfortunately, the EIP scrolled off
> screen, so I can't get a line number.
>
> (I had the same STR breakage as him; STR did not work with CPU_IDLE turned
> on, and it did work with CPU_IDLE turned off.)
>
> I'm running +rc6+mm(April 11) on a Sony VAIO SZ.
Looks there is init order issue of sysfs files. The new refreshed patch
should fix your bug.

Signed-off-by: Shaohua Li <shaohua.li@intel.com>

Index: 21-rc6-mm1/drivers/acpi/processor_idle.c
===================================================================
--- 21-rc6-mm1.orig/drivers/acpi/processor_idle.c 2007-04-17 13:41:29.000000000 +0800
+++ 21-rc6-mm1/drivers/acpi/processor_idle.c 2007-04-17 14:03:56.000000000 +0800
@@ -624,7 +624,7 @@ int acpi_processor_cst_has_changed(struc
return -ENODEV;

acpi_processor_get_power_info(pr);
- return cpuidle_force_redetect(&per_cpu(cpuidle_devices, pr->id));
+ return cpuidle_force_redetect(per_cpu(cpuidle_devices, pr->id));
}

/* proc interface */
Index: 21-rc6-mm1/drivers/cpuidle/cpuidle.c
===================================================================
--- 21-rc6-mm1.orig/drivers/cpuidle/cpuidle.c 2007-04-17 13:41:29.000000000 +0800
+++ 21-rc6-mm1/drivers/cpuidle/cpuidle.c 2007-04-17 14:42:17.000000000 +0800
@@ -18,7 +18,7 @@

#include "cpuidle.h"

-DEFINE_PER_CPU(struct cpuidle_device, cpuidle_devices);
+DEFINE_PER_CPU(struct cpuidle_device *, cpuidle_devices);
EXPORT_PER_CPU_SYMBOL_GPL(cpuidle_devices);

DEFINE_MUTEX(cpuidle_lock);
@@ -34,13 +34,13 @@ static void (*pm_idle_old)(void);
*/
static void cpuidle_idle_call(void)
{
- struct cpuidle_device *dev = &__get_cpu_var(cpuidle_devices);
+ struct cpuidle_device *dev = __get_cpu_var(cpuidle_devices);

struct cpuidle_state *target_state;
int next_state;

/* check if the device is ready */
- if (dev->status != CPUIDLE_STATUS_DOIDLE) {
+ if (!dev || dev->status != CPUIDLE_STATUS_DOIDLE) {
if (pm_idle_old)
pm_idle_old();
return;
@@ -117,19 +117,32 @@ static int cpuidle_add_device(struct sys
int cpu = sys_dev->id;
struct cpuidle_device *dev;

- dev = &per_cpu(cpuidle_devices, cpu);
+ dev = per_cpu(cpuidle_devices, cpu);

- dev->cpu = cpu;
mutex_lock(&cpuidle_lock);
if (cpu_is_offline(cpu)) {
mutex_unlock(&cpuidle_lock);
return 0;
}

+ if (!dev) {
+ dev = kzalloc(sizeof(struct cpuidle_device), GFP_KERNEL);
+ if (!dev) {
+ mutex_unlock(&cpuidle_lock);
+ return -ENOMEM;
+ }
+ init_completion(&dev->kobj_unregister);
+ per_cpu(cpuidle_devices, cpu) = dev;
+ }
+ dev->cpu = cpu;
+
if (dev->status & CPUIDLE_STATUS_DETECTED) {
mutex_unlock(&cpuidle_lock);
return 0;
}
+
+ cpuidle_add_sysfs(sys_dev);
+
if (cpuidle_curr_driver) {
if (cpuidle_attach_driver(dev))
goto err_ret;
@@ -146,7 +159,6 @@ static int cpuidle_add_device(struct sys
cpuidle_install_idle_handler();

list_add(&dev->device_list, &cpuidle_detected_devices);
- cpuidle_add_sysfs(sys_dev);
dev->status |= CPUIDLE_STATUS_DETECTED;

err_ret:
@@ -165,7 +177,7 @@ static int __cpuidle_remove_device(struc
{
struct cpuidle_device *dev;

- dev = &per_cpu(cpuidle_devices, sys_dev->id);
+ dev = per_cpu(cpuidle_devices, sys_dev->id);

if (!(dev->status & CPUIDLE_STATUS_DETECTED)) {
return 0;
@@ -178,6 +190,9 @@ static int __cpuidle_remove_device(struc
cpuidle_detach_driver(dev);
cpuidle_remove_sysfs(sys_dev);
list_del(&dev->device_list);
+ wait_for_completion(&dev->kobj_unregister);
+ per_cpu(cpuidle_devices, sys_dev->id) = NULL;
+ kfree(dev);

return 0;
}
Index: 21-rc6-mm1/drivers/cpuidle/sysfs.c
===================================================================
--- 21-rc6-mm1.orig/drivers/cpuidle/sysfs.c 2007-04-17 13:41:29.000000000 +0800
+++ 21-rc6-mm1/drivers/cpuidle/sysfs.c 2007-04-17 14:03:56.000000000 +0800
@@ -210,8 +210,16 @@ static struct sysfs_ops cpuidle_sysfs_op
.store = cpuidle_store,
};

+static void cpuidle_sysfs_release(struct kobject *kobj)
+{
+ struct cpuidle_device *dev = kobj_to_cpuidledev(kobj);
+
+ complete(&dev->kobj_unregister);
+}
+
static struct kobj_type ktype_cpuidle = {
.sysfs_ops = &cpuidle_sysfs_ops,
+ .release = cpuidle_sysfs_release,
};

struct cpuidle_state_attr {
@@ -246,7 +254,8 @@ static struct attribute *cpuidle_state_d
NULL
};

-#define kobj_to_state(k) container_of(k, struct cpuidle_state, kobj)
+#define kobj_to_state_obj(k) container_of(k, struct cpuidle_state_kobj, kobj)
+#define kobj_to_state(k) (kobj_to_state_obj(k)->state)
#define attr_to_stateattr(a) container_of(a, struct cpuidle_state_attr, attr)
static ssize_t cpuidle_state_show(struct kobject * kobj,
struct attribute * attr ,char * buf)
@@ -265,11 +274,27 @@ static struct sysfs_ops cpuidle_state_sy
.show = cpuidle_state_show,
};

+static void cpuidle_state_sysfs_release(struct kobject *kobj)
+{
+ struct cpuidle_state_kobj *state_obj = kobj_to_state_obj(kobj);
+
+ complete(&state_obj->kobj_unregister);
+}
+
static struct kobj_type ktype_state_cpuidle = {
.sysfs_ops = &cpuidle_state_sysfs_ops,
.default_attrs = cpuidle_state_default_attrs,
+ .release = cpuidle_state_sysfs_release,
};

+static void inline cpuidle_free_state_kobj(struct cpuidle_device *device, int i)
+{
+ kobject_unregister(&device->kobjs[i]->kobj);
+ wait_for_completion(&device->kobjs[i]->kobj_unregister);
+ kfree(device->kobjs[i]);
+ device->kobjs[i] = NULL;
+}
+
/**
* cpuidle_add_driver_sysfs - adds driver-specific sysfs attributes
* @device: the target device
@@ -277,24 +302,32 @@ static struct kobj_type ktype_state_cpui
int cpuidle_add_driver_sysfs(struct cpuidle_device *device)
{
int i, ret;
- struct cpuidle_state *state;
+ struct cpuidle_state_kobj *kobj;

/* state statistics */
for (i = 0; i < device->state_count; i++) {
- state = &device->states[i];
- state->kobj.parent = &device->kobj;
- state->kobj.ktype = &ktype_state_cpuidle;
- kobject_set_name(&state->kobj, "state%d", i);
- ret = kobject_register(&state->kobj);
- if (ret)
+ kobj = kzalloc(sizeof(struct cpuidle_state_kobj), GFP_KERNEL);
+ if (!kobj)
+ goto error_state;
+ kobj->state = &device->states[i];
+ init_completion(&kobj->kobj_unregister);
+
+ kobj->kobj.parent = &device->kobj;
+ kobj->kobj.ktype = &ktype_state_cpuidle;
+ kobject_set_name(&kobj->kobj, "state%d", i);
+ ret = kobject_register(&kobj->kobj);
+ if (ret) {
+ kfree(kobj);
goto error_state;
+ }
+ device->kobjs[i] = kobj;
}

return 0;

error_state:
for (i = i - 1; i >= 0; i--)
- kobject_unregister(&device->states[i].kobj);
+ cpuidle_free_state_kobj(device, i);
return ret;
}

@@ -307,7 +340,7 @@ void cpuidle_remove_driver_sysfs(struct
int i;

for (i = 0; i < device->state_count; i++)
- kobject_unregister(&device->states[i].kobj);
+ cpuidle_free_state_kobj(device, i);
}

/**
@@ -319,7 +352,7 @@ int cpuidle_add_sysfs(struct sys_device
int cpu = sysdev->id;
struct cpuidle_device *dev;

- dev = &per_cpu(cpuidle_devices, cpu);
+ dev = per_cpu(cpuidle_devices, cpu);
dev->kobj.parent = &sysdev->kobj;
dev->kobj.ktype = &ktype_cpuidle;
kobject_set_name(&dev->kobj, "%s", "cpuidle");
@@ -335,6 +368,6 @@ void cpuidle_remove_sysfs(struct sys_dev
int cpu = sysdev->id;
struct cpuidle_device *dev;

- dev = &per_cpu(cpuidle_devices, cpu);
+ dev = per_cpu(cpuidle_devices, cpu);
kobject_unregister(&dev->kobj);
}
Index: 21-rc6-mm1/include/linux/cpuidle.h
===================================================================
--- 21-rc6-mm1.orig/include/linux/cpuidle.h 2007-04-17 13:41:29.000000000 +0800
+++ 21-rc6-mm1/include/linux/cpuidle.h 2007-04-17 14:03:56.000000000 +0800
@@ -41,8 +41,6 @@ struct cpuidle_state {

int (*enter) (struct cpuidle_device *dev,
struct cpuidle_state *state);
-
- struct kobject kobj;
};

/* Idle State Flags */
@@ -74,6 +72,12 @@ cpuidle_set_statedata(struct cpuidle_sta
state->driver_data = data;
}

+struct cpuidle_state_kobj {
+ struct cpuidle_state *state;
+ struct completion kobj_unregister;
+ struct kobject kobj;
+};
+
struct cpuidle_device {
unsigned int status;
int cpu;
@@ -81,6 +85,7 @@ struct cpuidle_device {
int last_residency;
int state_count;
struct cpuidle_state states[CPUIDLE_STATE_MAX];
+ struct cpuidle_state_kobj *kobjs[CPUIDLE_STATE_MAX];
struct cpuidle_state *last_state;

struct list_head device_list;
@@ -89,9 +94,7 @@ struct cpuidle_device {
void *governor_data;
};

-#define to_cpuidle_device(n) container_of(n, struct cpuidle_device, kobj);
-
-DECLARE_PER_CPU(struct cpuidle_device, cpuidle_devices);
+DECLARE_PER_CPU(struct cpuidle_device *, cpuidle_devices);

/* Device Status Flags */
#define CPUIDLE_STATUS_DETECTED (0x1)