Hi Greg, The appended patch should fix the regreesions reported at: http://bugzilla.kernel.org/show_bug.cgi?id=9874 http://bugzilla.kernel.org/show_bug.cgi?id=10030 Please accept it for 2.6.25. Thanks, Rafael --- From: Rafael J. Wysocki <rjw@xxxxxxx> Remove the code that acquires all device semaphores from the suspend code path as it causes multiple problems to appear (most notably, http://bugzilla.kernel.org/show_bug.cgi?id=10030) and revert the change introduced by commit 4145ed6dc597a9bea5f6ae8c574653b2de10620f depending on the code being removed. Remove pm_sleep_lock()/pm_sleep_unlock() from device_add() to avoid the issue reported at http://bugzilla.kernel.org/show_bug.cgi?id=9874. Signed-off-by: Rafael J. Wysocki <rjw@xxxxxxx> --- drivers/base/core.c | 8 --- drivers/base/power/main.c | 106 ++++++---------------------------------------- drivers/usb/core/usb.c | 2 3 files changed, 17 insertions(+), 99 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); } /** @@ -230,6 +206,8 @@ static int resume_device(struct device * TRACE_DEVICE(dev); TRACE_RESUME(0); + down(&dev->sem); + if (dev->bus && dev->bus->resume) { dev_dbg(dev,"resuming\n"); error = dev->bus->resume(dev); @@ -245,6 +223,8 @@ static int resume_device(struct device * error = dev->class->resume(dev); } + up(&dev->sem); + TRACE_RESUME(error); return error; } @@ -266,7 +246,7 @@ 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 +255,6 @@ 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 +266,6 @@ 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 +284,6 @@ void device_resume(void) { might_sleep(); dpm_resume(); - unlock_all_devices(); unregister_dropped_devices(); up_write(&pm_sleep_rwsem); } @@ -388,18 +347,15 @@ int device_power_down(pm_message_t state struct list_head *entry = dpm_off.prev; struct device *dev = to_device(entry); - list_del_init(&dev->power.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); - if (list_empty(&dev->power.entry)) - list_add(&dev->power.entry, &dpm_off); break; } - if (list_empty(&dev->power.entry)) - list_add(&dev->power.entry, &dpm_off_irq); + if (!list_empty(&dev->power.entry)) + list_move(&dev->power.entry, &dpm_off_irq); } if (!error) @@ -419,6 +375,8 @@ static int suspend_device(struct device { 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); @@ -441,6 +399,9 @@ static int suspend_device(struct device error = dev->bus->suspend(dev, state); suspend_report_result(dev->bus->suspend, error); } + + up(&dev->sem); + return error; } @@ -461,11 +422,10 @@ 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); mutex_unlock(&dpm_list_mtx); error = suspend_device(dev, state); if (error) { @@ -476,14 +436,11 @@ static int dpm_suspend(pm_message_t stat (error == -EAGAIN ? " (please convert to suspend_late)" : "")); - mutex_lock(&dpm_list_mtx); - if (list_empty(&dev->power.entry)) - list_add(&dev->power.entry, &dpm_locked); break; } mutex_lock(&dpm_list_mtx); - if (list_empty(&dev->power.entry)) - list_add(&dev->power.entry, &dpm_off); + if (!list_empty(&dev->power.entry)) + list_move(&dev->power.entry, &dpm_off); } mutex_unlock(&dpm_list_mtx); @@ -491,36 +448,6 @@ 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 +460,6 @@ 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(); Index: linux-2.6/drivers/usb/core/usb.c =================================================================== --- linux-2.6.orig/drivers/usb/core/usb.c +++ linux-2.6/drivers/usb/core/usb.c @@ -234,7 +234,7 @@ static int ksuspend_usb_init(void) * singlethreaded. Its job doesn't justify running on more * than one CPU. */ - ksuspend_usb_wq = create_singlethread_workqueue("ksuspend_usbd"); + ksuspend_usb_wq = create_freezeable_workqueue("ksuspend_usbd"); if (!ksuspend_usb_wq) return -ENOMEM; return 0; Index: linux-2.6/drivers/base/core.c =================================================================== --- linux-2.6.orig/drivers/base/core.c +++ linux-2.6/drivers/base/core.c @@ -770,13 +770,6 @@ int device_add(struct device *dev) struct class_interface *class_intf; int error; - error = pm_sleep_lock(); - if (error) { - dev_warn(dev, "Suspicious %s during suspend\n", __FUNCTION__); - dump_stack(); - return error; - } - dev = get_device(dev); if (!dev || !strlen(dev->bus_id)) { error = -EINVAL; @@ -843,7 +836,6 @@ int device_add(struct device *dev) } Done: put_device(dev); - pm_sleep_unlock(); return error; BusError: device_pm_remove(dev); - To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
