On Thursday, 21 of February 2008, Julian Blake Kongslie wrote:
> I'm getting a hang at suspend on 2.6.25-rc2. Booting with
> no_console_suspend let me catch the error, which I photographed and
> transcribed (hopefully without error) below.
> 
> This is a Lenovo Thinkpad T43p.
> 
> I've attached my config and a partial dmesg (this machine generates a
> lot of messages at boot, and overfills the buffer before klogd gets to
> it).

Can you please apply the appened patch and retest?

Thanks,
Rafael

---
 drivers/base/power/main.c |   84 ++--------------------------------------------
 1 file changed, 4 insertions(+), 80 deletions(-)

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
@@ -48,7 +48,6 @@
  */
 
 LIST_HEAD(dpm_active);
-static LIST_HEAD(dpm_locked);
 static LIST_HEAD(dpm_off);
 static LIST_HEAD(dpm_off_irq);
 static LIST_HEAD(dpm_destroy);
@@ -81,28 +80,6 @@ void device_pm_add(struct device *dev)
  */
 void device_pm_remove(struct device *dev)
 {
-       /*
-        * If this function is called during a suspend, it will be blocked,
-        * because we're holding the device's semaphore at that time, which may
-        * lead to a deadlock.  In that case we want to print a warning.
-        * However, it may also be called by unregister_dropped_devices() with
-        * the device's semaphore released, in which case the warning should
-        * not be printed.
-        */
-       if (down_trylock(&dev->sem)) {
-               if (down_read_trylock(&pm_sleep_rwsem)) {
-                       /* No suspend in progress, wait on dev->sem */
-                       down(&dev->sem);
-                       up_read(&pm_sleep_rwsem);
-               } else {
-                       /* Suspend in progress, we may deadlock */
-                       dev_warn(dev, "Suspicious %s during suspend\n",
-                               __FUNCTION__);
-                       dump_stack();
-                       /* The user has been warned ... */
-                       down(&dev->sem);
-               }
-       }
        pr_debug("PM: Removing info for %s:%s\n",
                 dev->bus ? dev->bus->name : "No Bus",
                 kobject_name(&dev->kobj));
@@ -110,7 +87,6 @@ void device_pm_remove(struct device *dev
        dpm_sysfs_remove(dev);
        list_del_init(&dev->power.entry);
        mutex_unlock(&dpm_list_mtx);
-       up(&dev->sem);
 }
 
 /**
@@ -266,7 +242,7 @@ static void dpm_resume(void)
                struct list_head *entry = dpm_off.next;
                struct device *dev = to_device(entry);
 
-               list_move_tail(entry, &dpm_locked);
+               list_move_tail(entry, &dpm_active);
                mutex_unlock(&dpm_list_mtx);
                resume_device(dev);
                mutex_lock(&dpm_list_mtx);
@@ -275,25 +251,6 @@ static void dpm_resume(void)
 }
 
 /**
- *     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 unlock_all_devices(void)
-{
-       mutex_lock(&dpm_list_mtx);
-       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);
-}
-
-/**
  *     unregister_dropped_devices - Unregister devices scheduled for removal
  *
  *     Unregister all devices on the dpm_destroy list.
@@ -305,7 +262,6 @@ static void unregister_dropped_devices(v
                struct list_head *entry = dpm_destroy.next;
                struct device *dev = to_device(entry);
 
-               up(&dev->sem);
                mutex_unlock(&dpm_list_mtx);
                /* This also removes the device from the list */
                device_unregister(dev);
@@ -324,7 +280,6 @@ void device_resume(void)
 {
        might_sleep();
        dpm_resume();
-       unlock_all_devices();
        unregister_dropped_devices();
        up_write(&pm_sleep_rwsem);
 }
@@ -461,8 +416,8 @@ static int dpm_suspend(pm_message_t stat
        int error = 0;
 
        mutex_lock(&dpm_list_mtx);
-       while (!list_empty(&dpm_locked)) {
-               struct list_head *entry = dpm_locked.prev;
+       while (!list_empty(&dpm_active)) {
+               struct list_head *entry = dpm_active.prev;
                struct device *dev = to_device(entry);
 
                list_del_init(&dev->power.entry);
@@ -478,7 +433,7 @@ static int dpm_suspend(pm_message_t stat
                                        ""));
                        mutex_lock(&dpm_list_mtx);
                        if (list_empty(&dev->power.entry))
-                               list_add(&dev->power.entry, &dpm_locked);
+                               list_add_tail(&dev->power.entry, &dpm_active);
                        break;
                }
                mutex_lock(&dpm_list_mtx);
@@ -491,36 +446,6 @@ static int dpm_suspend(pm_message_t stat
 }
 
 /**
- *     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.
- */
-static void lock_all_devices(void)
-{
-       mutex_lock(&dpm_list_mtx);
-       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);
-               down(&dev->sem);
-               mutex_lock(&dpm_list_mtx);
-
-               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);
-}
-
-/**
  *     device_suspend - Save state and stop all devices in system.
  *     @state: new power management state
  *
@@ -533,7 +458,6 @@ int device_suspend(pm_message_t state)
 
        might_sleep();
        down_write(&pm_sleep_rwsem);
-       lock_all_devices();
        error = dpm_suspend(state);
        if (error)
                device_resume();
--
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