From mboxrd@z Thu Jan 1 00:00:00 1970 From: Michael Trimarchi Subject: Re: [RFC Add in_use attribute] Let the driver know if it's in use Date: Thu, 23 Apr 2009 18:49:20 +0200 Message-ID: <49F09C10.9080402@gandalf.sssup.it> References: <20090416131323.GA16752@gandalf.sssup.it> <20090421215632.GB10343@kroah.com> <49F02B2A.7030701@gandalf.sssup.it> <200904231659.20598.rjw@sisk.pl> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <200904231659.20598.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: Greg KH , linux-pm@lists.linux-foundation.org, pavel@suse.cz, len.brown@intel.com List-Id: linux-pm@vger.kernel.org Hi, Rafael J. Wysocki wrote: > On Thursday 23 April 2009, Michael Trimarchi wrote: > >> Greg KH wrote: >> >>> On Tue, Apr 21, 2009 at 08:43:28AM +0200, Michael Trimarchi wrote: >>> >>> >>>>>>> Exactly, what are you trying to do that differs from >>>>>>> device_for_each_child()? >>>>>>> >>>>>>> >>>>>>> >>>>>>> >>>>>> Is device for each child use to visist the first level of the tree? >>>>>> >>>>>> >>>>>> >>>>> Have you tried it? >>>>> >>>>> >>>>> >>>> No, I take a look at the code. >>>> >>>> int device_for_each_child(struct device *parent, void *data, >>>> int (*fn)(struct device *dev, void *data)) >>>> { >>>> struct klist_iter i; >>>> struct device *child; >>>> int error = 0; >>>> >>>> klist_iter_init(&parent->p->klist_children, &i); >>>> >>>> I was thinking that the klist_children is the fist_level one children, >>>> so each time >>>> a device is registerd it add the link to the parent. >>>> >>>> >>> Yes it does. >>> >>> But you have to start at some device, right? So you don't need to >>> iterate over it, just go from there on down if needed. >>> >>> >> I start for a device, go down until I find a leaf or find that the >> subtree is marked. >> Mark the leaf and go up and take the next node like the walk_tg_tree. >> The difference is >> that I skip subtree if they are mark in_use. >> >>> So I don't see why this helper function is needed at all yet, shouldn't >>> we be doing the check within the normal suspend device walk of the tree? >>> >>> >> Sorry but here I need some help here. Where is the walk of the device >> tree during suspend? >> > > > In drivers/base/power/main.c there are functions like dpm_suspend(), for one > example, that walk the device tree, but they do it in a simplified way, using a > list prepared specifically for this purpose (so the walk is in fact linear). > I don't want add a new list and If I use the dpm_list a must go back to the root for each element using the parent and check the flag because the list maybe don't mantein the parent relation. example: s(A) is son of A ss(A) etc A-B-s(B)-s(B)-s(A)-ss(B)-ss(A) I don't know if B the second element has child of B I must look it's parent and so on. So the complexty increase. The suspend order is correct but the computation time is worse. Maybe I can move the code outside the base/core.c and put it in the power/main.c but I don't have the next_device function and other to move up and down. I put there that function because I have all the necessary code. Michael > Thanks, > Rafael > >