From 58aca23226a19983571bd3b65167521fc64f5869 Mon Sep 17 00:00:00 2001 From: "Rafael J. Wysocki" Date: Wed, 12 Mar 2008 00:57:22 +0100 Subject: PM: Handle device registrations during suspend/resume Modify the PM core to protect its data structures, specifically the dpm_active list, from being corrupted if a child of the currently suspending device is registered concurrently with its ->suspend() callback. In that case, since the new device (the child) is added to dpm_active after its parent, the PM core will attempt to suspend it after the parent, which is wrong. Introduce a new member of struct dev_pm_info, called 'sleeping', and use it to check if the parent of the device being added to dpm_active has been suspended, in which case the device registration fails. Also, use 'sleeping' for checking if the ordering of devices on dpm_active is correct. Introduce variable 'all_sleeping' that will be set to 'true' once all devices have been suspended and make new device registrations fail until 'all_sleeping' is reset to 'false', in order to avoid having unsuspended devices around while the system is going into a sleep state. Remove pm_sleep_rwsem which is not necessary any more. Special thanks to Alan Stern for discussions and suggestions that lead to the creation of this patch. Signed-off-by: Rafael J. Wysocki Acked-by: Pavel Machek Signed-off-by: Greg Kroah-Hartman --- include/linux/pm.h | 1 + 1 file changed, 1 insertion(+) (limited to 'include/linux') diff --git a/include/linux/pm.h b/include/linux/pm.h index 015b735811b..e6b9f29e27d 100644 --- a/include/linux/pm.h +++ b/include/linux/pm.h @@ -183,6 +183,7 @@ typedef struct pm_message { struct dev_pm_info { pm_message_t power_state; unsigned can_wakeup:1; + bool sleeping:1; /* Owned by the PM core */ #ifdef CONFIG_PM_SLEEP unsigned should_wakeup:1; struct list_head entry; -- cgit v1.2.3