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    SubjectRe: [PATCH] PM: Acquire device locks on suspend
    Date
    On Saturday, 5 of January 2008, Alan Stern wrote:
    > On Sat, 5 Jan 2008, Rafael J. Wysocki wrote:
    >
    > > On Saturday, 5 of January 2008, Alan Stern wrote:
    > > > On Sat, 5 Jan 2008, Rafael J. Wysocki wrote:
    > > >
    > > > > > Another thing to watch out for: Just in case somebody ends up calling
    > > > > > destroy_suspended_device(dev) from within dev's own resume method, you
    > > > > > should interchange the resume_device() and the list_move_tail()
    > > > > > calls in dpm_resume().
    > > > >
    > > > > However, if we unregister them all at once after releasing pm_sleep_rwsem,
    > > > > that shouldn't be necessary, right?
    > > >
    > > > It's still necessary, because destroy_suspended_device() still has to
    > > > move the device from one list to another. You don't want it to end up
    > > > on the dpm_locked list.
    > >
    > > Hmm. That means we'd have to do the same thing in dpm_power_up() in case
    > > someone calls destroy_suspended_device() from resume_device_early(dev).
    >
    > Yes.
    >
    > > Still, even doing that is not enough, since someone can call
    > > destroy_suspended_device() from a .suspend() routine and then the device
    > > will end up on a wrong list just as well.
    >
    > That should never happen. The whole idea of destroy_suspended_device()
    > is that the device couldn't be resumed and in fact should be
    > unregistered because it is no longer working or no longer present. A
    > suspend routine won't detect this sort of thing since it doesn't try to
    > resume the device.
    >
    > But it wouldn't hurt to mention in the kerneldoc that
    > destroy_suspended_device() is meant to be called only during a system
    > resume.

    Hmm. Please have a look at the appended patch.

    I have removed the warning from device_del() and used list_empty() to detect
    removed devices in the .suspend() routines. Is that viable?

    Rafael


    ---
    arch/x86/kernel/cpuid.c | 6
    arch/x86/kernel/msr.c | 6
    drivers/base/core.c | 67 +++++-
    drivers/base/power/main.c | 454 ++++++++++++++++++++++++++-------------------
    drivers/base/power/power.h | 12 +
    include/linux/device.h | 8
    6 files changed, 354 insertions(+), 199 deletions(-)

    Index: linux-2.6/drivers/base/core.c
    ===================================================================
    --- linux-2.6.orig/drivers/base/core.c
    +++ linux-2.6/drivers/base/core.c
    @@ -726,11 +726,20 @@ int device_add(struct device *dev)
    {
    struct device *parent = NULL;
    struct class_interface *class_intf;
    - int error = -EINVAL;
    + int error;
    +
    + error = pm_sleep_lock();
    + if (error) {
    + dev_warn(dev, "Illegal %s during suspend\n", __FUNCTION__);
    + dump_stack();
    + return error;
    + }

    dev = get_device(dev);
    - if (!dev || !strlen(dev->bus_id))
    - goto Error;
    + if (!dev || !strlen(dev->bus_id)) {
    + error = -EINVAL;
    + goto Done;
    + }

    pr_debug("DEV: registering device: ID = '%s'\n", dev->bus_id);

    @@ -795,6 +804,7 @@ int device_add(struct device *dev)
    }
    Done:
    put_device(dev);
    + pm_sleep_unlock();
    return error;
    BusError:
    device_pm_remove(dev);
    @@ -1156,14 +1173,11 @@ error:
    EXPORT_SYMBOL_GPL(device_create);

    /**
    - * device_destroy - removes a device that was created with device_create()
    + * find_device - finds a device that was created with device_create()
    * @class: pointer to the struct class that this device was registered with
    * @devt: the dev_t of the device that was previously registered
    - *
    - * This call unregisters and cleans up a device that was created with a
    - * call to device_create().
    */
    -void device_destroy(struct class *class, dev_t devt)
    +static struct device *find_device(struct class *class, dev_t devt)
    {
    struct device *dev = NULL;
    struct device *dev_tmp;
    @@ -1176,12 +1190,49 @@ void device_destroy(struct class *class,
    }
    }
    up(&class->sem);
    + return dev;
    +}
    +
    +/**
    + * device_destroy - removes a device that was created with device_create()
    + * @class: pointer to the struct class that this device was registered with
    + * @devt: the dev_t of the device that was previously registered
    + *
    + * This call unregisters and cleans up a device that was created with a
    + * call to device_create().
    + */
    +void device_destroy(struct class *class, dev_t devt)
    +{
    + struct device *dev;

    + dev = find_device(class, devt);
    if (dev)
    device_unregister(dev);
    }
    EXPORT_SYMBOL_GPL(device_destroy);

    +#ifdef CONFIG_PM_SLEEP
    +/**
    + * destroy_suspended_device - asks the PM core to remove a suspended device
    + * @class: pointer to the struct class that this device was registered with
    + * @devt: the dev_t of the device that was previously registered
    + *
    + * This call causes the PM core to release and unregister a suspended device
    + * created with a call to device_create() (devices cannot be unregistered
    + * directly while suspended, since the PM core holds their semaphores at that
    + * time).
    + */
    +void destroy_suspended_device(struct class *class, dev_t devt)
    +{
    + struct device *dev;
    +
    + dev = find_device(class, devt);
    + if (dev)
    + device_pm_destroy_suspended(dev);
    +}
    +EXPORT_SYMBOL_GPL(destroy_suspended_device);
    +#endif /* CONFIG_PM_SLEEP */
    +
    /**
    * device_rename - renames a device
    * @dev: the pointer to the struct device to be renamed
    Index: linux-2.6/include/linux/device.h
    ===================================================================
    --- linux-2.6.orig/include/linux/device.h
    +++ linux-2.6/include/linux/device.h
    @@ -521,6 +521,14 @@ extern struct device *device_create(stru
    dev_t devt, const char *fmt, ...)
    __attribute__((format(printf,4,5)));
    extern void device_destroy(struct class *cls, dev_t devt);
    +#ifdef CONFIG_PM_SLEEP
    +extern void destroy_suspended_device(struct class *cls, dev_t devt);
    +#else /* !CONFIG_PM_SLEEP */
    +static inline void destroy_suspended_device(struct class *cls, dev_t devt)
    +{
    + device_destroy(cls, devt);
    +}
    +#endif /* !CONFIG_PM_SLEEP */

    /*
    * Platform "fixup" functions - allow the platform to have their say
    Index: linux-2.6/drivers/base/power/power.h
    ===================================================================
    --- linux-2.6.orig/drivers/base/power/power.h
    +++ linux-2.6/drivers/base/power/power.h
    @@ -20,6 +20,9 @@ static inline struct device *to_device(s

    extern void device_pm_add(struct device *);
    extern void device_pm_remove(struct device *);
    +extern void device_pm_destroy_suspended(struct device *);
    +extern int pm_sleep_lock(void);
    +extern void pm_sleep_unlock(void);

    #else /* CONFIG_PM_SLEEP */

    @@ -32,6 +35,15 @@ static inline void device_pm_remove(stru
    {
    }

    +static inline int pm_sleep_lock(void)
    +{
    + return 0;
    +}
    +
    +static inline void pm_sleep_unlock(void)
    +{
    +}
    +
    #endif

    #ifdef CONFIG_PM
    Index: linux-2.6/drivers/base/power/main.c
    ===================================================================
    --- linux-2.6.orig/drivers/base/power/main.c
    +++ linux-2.6/drivers/base/power/main.c
    @@ -24,17 +24,38 @@
    #include <linux/mutex.h>
    #include <linux/pm.h>
    #include <linux/resume-trace.h>
    +#include <linux/rwsem.h>

    #include "../base.h"
    #include "power.h"

    +/*
    + * The entries in the dpm_active list are in a depth first order, simply
    + * because children are guaranteed to be discovered after parents, and
    + * are inserted at the back of the list on discovery.
    + *
    + * All the other lists are kept in the same order, for consistency.
    + * However the lists aren't always traversed in the same order.
    + * Semaphores must be acquired from the top (i.e., front) down
    + * and released in the opposite order. Devices must be suspended
    + * from the bottom (i.e., end) up and resumed in the opposite order.
    + * That way no parent will be suspended while it still has an active
    + * child.
    + *
    + * Since device_pm_add() may be called with a device semaphore held,
    + * we must never try to acquire a device semaphore while holding
    + * dpm_list_mutex.
    + */
    +
    LIST_HEAD(dpm_active);
    +static LIST_HEAD(dpm_locked);
    static LIST_HEAD(dpm_off);
    static LIST_HEAD(dpm_off_irq);

    -static DEFINE_MUTEX(dpm_mtx);
    static DEFINE_MUTEX(dpm_list_mtx);

    +static DECLARE_RWSEM(pm_sleep_rwsem);
    +
    int (*platform_enable_wakeup)(struct device *dev, int is_on);


    @@ -53,29 +74,124 @@ void device_pm_remove(struct device *dev
    pr_debug("PM: Removing info for %s:%s\n",
    dev->bus ? dev->bus->name : "No Bus",
    kobject_name(&dev->kobj));
    +
    + /* Don't remove a device while the PM core has it locked for suspend */
    + down(&dev->sem);
    mutex_lock(&dpm_list_mtx);
    dpm_sysfs_remove(dev);
    list_del_init(&dev->power.entry);
    mutex_unlock(&dpm_list_mtx);
    + up(&dev->sem);
    +}
    +
    +void device_pm_destroy_suspended(struct device *dev)
    +{
    + pr_debug("PM: Removing suspended device %s:%s\n",
    + dev->bus ? dev->bus->name : "No Bus",
    + kobject_name(&dev->kobj));
    + mutex_lock(&dpm_list_mtx);
    + list_del_init(&dev->power.entry);
    + mutex_unlock(&dpm_list_mtx);
    + up(&dev->sem);
    + device_unregister(dev);
    +}
    +
    +/**
    + * pm_sleep_lock - mutual exclusion for registration and suspend
    + *
    + * Returns 0 if no suspend is underway and device registration
    + * may proceed, otherwise -EBUSY.
    + */
    +int pm_sleep_lock(void)
    +{
    + if (down_read_trylock(&pm_sleep_rwsem))
    + return 0;
    + return -EBUSY;
    +}
    +
    +/**
    + * pm_sleep_unlock - mutual exclusion for registration and suspend
    + *
    + * This routine undoes the effect of device_pm_add_lock
    + * when a device's registration is complete.
    + */
    +void pm_sleep_unlock(void)
    +{
    + up_read(&pm_sleep_rwsem);
    }


    /*------------------------- Resume routines -------------------------*/

    /**
    - * resume_device - Restore state for one device.
    + * resume_device_early - Power on one device (early resume).
    * @dev: Device.
    *
    + * Must be called with interrupts disabled.
    */
    -
    -static int resume_device(struct device * dev)
    +static int resume_device_early(struct device *dev)
    {
    int error = 0;

    TRACE_DEVICE(dev);
    TRACE_RESUME(0);

    - down(&dev->sem);
    + if (dev->bus && dev->bus->resume_early) {
    + dev_dbg(dev,"EARLY resume\n");
    + error = dev->bus->resume_early(dev);
    + }
    +
    + TRACE_RESUME(error);
    + return error;
    +}
    +
    +/**
    + * dpm_power_up - Power on all regular (non-sysdev) devices.
    + *
    + * Walk the dpm_off_irq list and power each device up. This
    + * is used for devices that required they be powered down with
    + * interrupts disabled. As devices are powered on, they are moved
    + * to the dpm_off list.
    + *
    + * Interrupts must be disabled when calling this.
    + */
    +static void dpm_power_up(void)
    +{
    + while (!list_empty(&dpm_off_irq)) {
    + struct list_head *entry = dpm_off_irq.next;
    + struct device *dev = to_device(entry);
    +
    + list_move_tail(entry, &dpm_off);
    + resume_device_early(dev);
    + }
    +}
    +
    +/**
    + * device_power_up - Turn on all devices that need special attention.
    + *
    + * Power on system devices, then devices that required we shut them down
    + * with interrupts disabled.
    + *
    + * Must be called with interrupts disabled.
    + */
    +void device_power_up(void)
    +{
    + sysdev_resume();
    + dpm_power_up();
    +}
    +EXPORT_SYMBOL_GPL(device_power_up);
    +
    +/**
    + * resume_device - Restore state for one device.
    + * @dev: Device.
    + *
    + */
    +static int resume_device(struct device *dev)
    +{
    + int error = 0;
    +
    + TRACE_DEVICE(dev);
    + TRACE_RESUME(0);

    if (dev->bus && dev->bus->resume) {
    dev_dbg(dev,"resuming\n");
    @@ -92,126 +208,68 @@ static int resume_device(struct device *
    error = dev->class->resume(dev);
    }

    - up(&dev->sem);
    -
    TRACE_RESUME(error);
    return error;
    }

    -
    -static int resume_device_early(struct device * dev)
    +/**
    + * dpm_resume - Resume every device.
    + *
    + * Resume the devices that have either not gone through
    + * the late suspend, or that did go through it but also
    + * went through the early resume.
    + *
    + * Take devices from the dpm_off_list, resume them,
    + * and put them on the dpm_locked list.
    + */
    +static void dpm_resume(void)
    {
    - int error = 0;
    + while(!list_empty(&dpm_off)) {
    + struct list_head *entry = dpm_off.next;
    + struct device *dev = to_device(entry);

    - TRACE_DEVICE(dev);
    - TRACE_RESUME(0);
    - if (dev->bus && dev->bus->resume_early) {
    - dev_dbg(dev,"EARLY resume\n");
    - error = dev->bus->resume_early(dev);
    + resume_device(dev);
    + list_move_tail(entry, &dpm_locked);
    }
    - TRACE_RESUME(error);
    - return error;
    }

    -/*
    - * Resume the devices that have either not gone through
    - * the late suspend, or that did go through it but also
    - * went through the early resume
    +/**
    + * unlock_all_devices - Release each device's semaphore
    + *
    + * Go through the dpm_off list. Put each device on the dpm_active
    + * list and unlock it.
    */
    -static void dpm_resume(void)
    +static void unlock_all_devices(void)
    {
    mutex_lock(&dpm_list_mtx);
    - while(!list_empty(&dpm_off)) {
    - struct list_head * entry = dpm_off.next;
    - struct device * dev = to_device(entry);
    -
    - get_device(dev);
    - list_move_tail(entry, &dpm_active);
    -
    - mutex_unlock(&dpm_list_mtx);
    - resume_device(dev);
    - mutex_lock(&dpm_list_mtx);
    - put_device(dev);
    - }
    + while (!list_empty(&dpm_locked)) {
    + struct list_head *entry = dpm_locked.prev;
    + struct device *dev = to_device(entry);
    +
    + list_move(entry, &dpm_active);
    + up(&dev->sem);
    + }
    mutex_unlock(&dpm_list_mtx);
    }

    -
    /**
    * device_resume - Restore state of each device in system.
    *
    - * Walk the dpm_off list, remove each entry, resume the device,
    - * then add it to the dpm_active list.
    + * Resume all the devices, unlock them all, and allow new
    + * devices to be registered once again.
    */
    -
    void device_resume(void)
    {
    might_sleep();
    - mutex_lock(&dpm_mtx);
    dpm_resume();
    - mutex_unlock(&dpm_mtx);
    + unlock_all_devices();
    + up_write(&pm_sleep_rwsem);
    }
    -
    EXPORT_SYMBOL_GPL(device_resume);


    -/**
    - * dpm_power_up - Power on some devices.
    - *
    - * Walk the dpm_off_irq list and power each device up. This
    - * is used for devices that required they be powered down with
    - * interrupts disabled. As devices are powered on, they are moved
    - * to the dpm_active list.
    - *
    - * Interrupts must be disabled when calling this.
    - */
    -
    -static void dpm_power_up(void)
    -{
    - while(!list_empty(&dpm_off_irq)) {
    - struct list_head * entry = dpm_off_irq.next;
    - struct device * dev = to_device(entry);
    -
    - list_move_tail(entry, &dpm_off);
    - resume_device_early(dev);
    - }
    -}
    -
    -
    -/**
    - * device_power_up - Turn on all devices that need special attention.
    - *
    - * Power on system devices then devices that required we shut them down
    - * with interrupts disabled.
    - * Called with interrupts disabled.
    - */
    -
    -void device_power_up(void)
    -{
    - sysdev_resume();
    - dpm_power_up();
    -}
    -
    -EXPORT_SYMBOL_GPL(device_power_up);
    -
    -
    /*------------------------- Suspend routines -------------------------*/

    -/*
    - * The entries in the dpm_active list are in a depth first order, simply
    - * because children are guaranteed to be discovered after parents, and
    - * are inserted at the back of the list on discovery.
    - *
    - * All list on the suspend path are done in reverse order, so we operate
    - * on the leaves of the device tree (or forests, depending on how you want
    - * to look at it ;) first. As nodes are removed from the back of the list,
    - * they are inserted into the front of their destintation lists.
    - *
    - * Things are the reverse on the resume path - iterations are done in
    - * forward order, and nodes are inserted at the back of their destination
    - * lists. This way, the ancestors will be accessed before their descendents.
    - */
    -
    static inline char *suspend_verb(u32 event)
    {
    switch (event) {
    @@ -222,7 +280,6 @@ static inline char *suspend_verb(u32 eve
    }
    }

    -
    static void
    suspend_device_dbg(struct device *dev, pm_message_t state, char *info)
    {
    @@ -232,16 +289,70 @@ suspend_device_dbg(struct device *dev, p
    }

    /**
    - * suspend_device - Save state of one device.
    + * suspend_device_late - Shut down one device (late suspend).
    * @dev: Device.
    * @state: Power state device is entering.
    + *
    + * This is called with interrupts off and only a single CPU running.
    */
    +static int suspend_device_late(struct device *dev, pm_message_t state)
    +{
    + int error = 0;

    -static int suspend_device(struct device * dev, pm_message_t state)
    + if (dev->bus && dev->bus->suspend_late) {
    + suspend_device_dbg(dev, state, "LATE ");
    + error = dev->bus->suspend_late(dev, state);
    + suspend_report_result(dev->bus->suspend_late, error);
    + }
    + return error;
    +}
    +
    +/**
    + * device_power_down - Shut down special devices.
    + * @state: Power state to enter.
    + *
    + * Power down devices that require interrupts to be disabled
    + * and move them from the dpm_off list to the dpm_off_irq list.
    + * Then power down system devices.
    + *
    + * Must be called with interrupts disabled and only one CPU running.
    + */
    +int device_power_down(pm_message_t state)
    +{
    + int error = 0;
    +
    + while (!list_empty(&dpm_off)) {
    + struct list_head *entry = dpm_off.prev;
    + struct device *dev = to_device(entry);
    +
    + error = suspend_device_late(dev, state);
    + if (error) {
    + printk(KERN_ERR "Could not power down device %s: "
    + "error %d\n",
    + kobject_name(&dev->kobj), error);
    + break;
    + }
    + if (!list_empty(&dev->power.entry))
    + list_move(&dev->power.entry, &dpm_off_irq);
    + }
    +
    + if (!error)
    + error = sysdev_suspend(state);
    + if (error)
    + dpm_power_up();
    + return error;
    +}
    +EXPORT_SYMBOL_GPL(device_power_down);
    +
    +/**
    + * suspend_device - Save state of one device.
    + * @dev: Device.
    + * @state: Power state device is entering.
    + */
    +int suspend_device(struct device *dev, pm_message_t state)
    {
    int error = 0;

    - down(&dev->sem);
    if (dev->power.power_state.event) {
    dev_dbg(dev, "PM: suspend %d-->%d\n",
    dev->power.power_state.event, state.event);
    @@ -264,123 +375,96 @@ static int suspend_device(struct device
    error = dev->bus->suspend(dev, state);
    suspend_report_result(dev->bus->suspend, error);
    }
    - up(&dev->sem);
    return error;
    }

    -
    -/*
    - * This is called with interrupts off, only a single CPU
    - * running. We can't acquire a mutex or semaphore (and we don't
    - * need the protection)
    +/**
    + * dpm_suspend - Suspend every device.
    + * @state: Power state to put each device in.
    + *
    + * Walk the dpm_locked list. Suspend each device and move it
    + * to the dpm_off list.
    + *
    + * (For historical reasons, if it returns -EAGAIN, that used to mean
    + * that the device would be called again with interrupts disabled.
    + * These days, we use the "suspend_late()" callback for that, so we
    + * print a warning and consider it an error).
    */
    -static int suspend_device_late(struct device *dev, pm_message_t state)
    +static int dpm_suspend(pm_message_t state)
    {
    int error = 0;

    - if (dev->bus && dev->bus->suspend_late) {
    - suspend_device_dbg(dev, state, "LATE ");
    - error = dev->bus->suspend_late(dev, state);
    - suspend_report_result(dev->bus->suspend_late, error);
    + while (!list_empty(&dpm_locked)) {
    + struct list_head *entry = dpm_locked.prev;
    + struct device *dev = to_device(entry);
    +
    + error = suspend_device(dev, state);
    + if (error) {
    + printk(KERN_ERR "Could not suspend device %s: "
    + "error %d%s\n",
    + kobject_name(&dev->kobj),
    + error,
    + (error == -EAGAIN ?
    + " (please convert to suspend_late)" :
    + ""));
    + break;
    + }
    + if (!list_empty(&dev->power.entry))
    + list_move(&dev->power.entry, &dpm_off);
    }
    +
    return error;
    }

    /**
    - * device_suspend - Save state and stop all devices in system.
    - * @state: Power state to put each device in.
    - *
    - * Walk the dpm_active list, call ->suspend() for each device, and move
    - * it to the dpm_off list.
    - *
    - * (For historical reasons, if it returns -EAGAIN, that used to mean
    - * that the device would be called again with interrupts disabled.
    - * These days, we use the "suspend_late()" callback for that, so we
    - * print a warning and consider it an error).
    - *
    - * If we get a different error, try and back out.
    - *
    - * If we hit a failure with any of the devices, call device_resume()
    - * above to bring the suspended devices back to life.
    + * lock_all_devices - Acquire every device's semaphore
    *
    + * Go through the dpm_active list. Carefully lock each device's
    + * semaphore and put it in on the dpm_locked list.
    */
    -
    -int device_suspend(pm_message_t state)
    +static void lock_all_devices(void)
    {
    - int error = 0;
    -
    - might_sleep();
    - mutex_lock(&dpm_mtx);
    mutex_lock(&dpm_list_mtx);
    - while (!list_empty(&dpm_active) && error == 0) {
    - struct list_head * entry = dpm_active.prev;
    - struct device * dev = to_device(entry);
    -
    + while (!list_empty(&dpm_active)) {
    + struct list_head *entry = dpm_active.next;
    + struct device *dev = to_device(entry);
    +
    + /* Required locking order is dev->sem first,
    + * then dpm_list_mutex. Hence this awkward code.
    + */
    get_device(dev);
    mutex_unlock(&dpm_list_mtx);
    -
    - error = suspend_device(dev, state);
    -
    + down(&dev->sem);
    mutex_lock(&dpm_list_mtx);

    - /* Check if the device got removed */
    - if (!list_empty(&dev->power.entry)) {
    - /* Move it to the dpm_off list */
    - if (!error)
    - list_move(&dev->power.entry, &dpm_off);
    - }
    - if (error)
    - printk(KERN_ERR "Could not suspend device %s: "
    - "error %d%s\n",
    - kobject_name(&dev->kobj), error,
    - error == -EAGAIN ? " (please convert to suspend_late)" : "");
    + if (list_empty(entry))
    + up(&dev->sem); /* Device was removed */
    + else
    + list_move_tail(entry, &dpm_locked);
    put_device(dev);
    }
    mutex_unlock(&dpm_list_mtx);
    - if (error)
    - dpm_resume();
    -
    - mutex_unlock(&dpm_mtx);
    - return error;
    }

    -EXPORT_SYMBOL_GPL(device_suspend);
    -
    /**
    - * device_power_down - Shut down special devices.
    - * @state: Power state to enter.
    + * device_suspend - Save state and stop all devices in system.
    *
    - * Walk the dpm_off_irq list, calling ->power_down() for each device that
    - * couldn't power down the device with interrupts enabled. When we're
    - * done, power down system devices.
    + * Prevent new devices from being registered, then lock all devices
    + * and suspend them.
    */
    -
    -int device_power_down(pm_message_t state)
    +int device_suspend(pm_message_t state)
    {
    - int error = 0;
    - struct device * dev;
    -
    - while (!list_empty(&dpm_off)) {
    - struct list_head * entry = dpm_off.prev;
    -
    - dev = to_device(entry);
    - error = suspend_device_late(dev, state);
    - if (error)
    - goto Error;
    - list_move(&dev->power.entry, &dpm_off_irq);
    - }
    + int error;

    - error = sysdev_suspend(state);
    - Done:
    + might_sleep();
    + down_write(&pm_sleep_rwsem);
    + lock_all_devices();
    + error = dpm_suspend(state);
    + if (error)
    + device_resume();
    return error;
    - Error:
    - printk(KERN_ERR "Could not power down device %s: "
    - "error %d\n", kobject_name(&dev->kobj), error);
    - dpm_power_up();
    - goto Done;
    }
    -
    -EXPORT_SYMBOL_GPL(device_power_down);
    +EXPORT_SYMBOL_GPL(device_suspend);

    void __suspend_report_result(const char *function, void *fn, int ret)
    {
    Index: linux-2.6/arch/x86/kernel/msr.c
    ===================================================================
    --- linux-2.6.orig/arch/x86/kernel/msr.c
    +++ linux-2.6/arch/x86/kernel/msr.c
    @@ -155,15 +155,15 @@ static int __cpuinit msr_class_cpu_callb

    switch (action) {
    case CPU_UP_PREPARE:
    - case CPU_UP_PREPARE_FROZEN:
    err = msr_device_create(cpu);
    break;
    case CPU_UP_CANCELED:
    - case CPU_UP_CANCELED_FROZEN:
    case CPU_DEAD:
    - case CPU_DEAD_FROZEN:
    msr_device_destroy(cpu);
    break;
    + case CPU_UP_CANCELED_FROZEN:
    + destroy_suspended_device(msr_class, MKDEV(MSR_MAJOR, cpu));
    + break;
    }
    return err ? NOTIFY_BAD : NOTIFY_OK;
    }
    Index: linux-2.6/arch/x86/kernel/cpuid.c
    ===================================================================
    --- linux-2.6.orig/arch/x86/kernel/cpuid.c
    +++ linux-2.6/arch/x86/kernel/cpuid.c
    @@ -157,15 +157,15 @@ static int __cpuinit cpuid_class_cpu_cal

    switch (action) {
    case CPU_UP_PREPARE:
    - case CPU_UP_PREPARE_FROZEN:
    err = cpuid_device_create(cpu);
    break;
    case CPU_UP_CANCELED:
    - case CPU_UP_CANCELED_FROZEN:
    case CPU_DEAD:
    - case CPU_DEAD_FROZEN:
    cpuid_device_destroy(cpu);
    break;
    + case CPU_UP_CANCELED_FROZEN:
    + destroy_suspended_device(cpuid_class, MKDEV(CPUID_MAJOR, cpu));
    + break;
    }
    return err ? NOTIFY_BAD : NOTIFY_OK;
    }

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      Last update: 2008-01-05 22:59    [W:0.082 / U:29.612 seconds]
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