From mboxrd@z Thu Jan 1 00:00:00 1970 From: Pavel Machek Subject: Re: [PATCH 1/3] PM: Handle device registrations during suspend/resume Date: Thu, 13 Mar 2008 09:37:13 +0100 Message-ID: <20080313083713.GA20299@elf.ucw.cz> References: <200803120055.25885.rjw@sisk.pl> <200803120057.23101.rjw@sisk.pl> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Content-Disposition: inline In-Reply-To: <200803120057.23101.rjw@sisk.pl> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: linux-pm-bounces@lists.linux-foundation.org Errors-To: linux-pm-bounces@lists.linux-foundation.org To: "Rafael J. Wysocki" Cc: LKML , Andrew Morton , pm list List-Id: linux-pm@vger.kernel.org On Wed 2008-03-12 00:57:22, Rafael J. Wysocki wrote: > From: Rafael J. Wysocki > > 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 ACK. -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html