Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756481AbYCEQ1V (ORCPT ); Wed, 5 Mar 2008 11:27:21 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752734AbYCEQ1H (ORCPT ); Wed, 5 Mar 2008 11:27:07 -0500 Received: from iolanthe.rowland.org ([192.131.102.54]:41649 "HELO iolanthe.rowland.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1752632AbYCEQ1E (ORCPT ); Wed, 5 Mar 2008 11:27:04 -0500 Date: Wed, 5 Mar 2008 11:27:03 -0500 (EST) From: Alan Stern X-X-Sender: stern@iolanthe.rowland.org To: "Rafael J. Wysocki" cc: pm list , Alexey Starikovskiy , Pavel Machek , LKML Subject: Re: [RFC][PATCH] PM: Make PM core handle device registrations concurrent with suspend/hibernation In-Reply-To: <200803050215.31195.rjw@sisk.pl> Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1710 Lines: 50 On Wed, 5 Mar 2008, Rafael J. Wysocki wrote: > -void device_pm_add(struct device *dev) > +int device_pm_add(struct device *dev) > { > + int error = 0; > + > pr_debug("PM: Adding info for %s:%s\n", > dev->bus ? dev->bus->name : "No Bus", > kobject_name(&dev->kobj)); > mutex_lock(&dpm_list_mtx); > - list_add_tail(&dev->power.entry, &dpm_active); > + if (dev->parent && dev->parent->power.sleeping) { > + WARN_ON(true); I would prefer to put a dev_warn() line here, so that people reading the kernel log can easily tell which device caused the problem and what sort of problem it is. Something like this: dev_warn(dev, "device added while parent %s is asleep\n", dev->parent->bus_id); WARN_ON(true); > @@ -426,6 +406,12 @@ static int dpm_suspend(pm_message_t stat > struct list_head *entry = dpm_active.prev; > struct device *dev = to_device(entry); > > + if (dev->parent && dev->parent->power.sleeping) { > + WARN_ON(true); > + error = -EAGAIN; > + break; Again, a dev_warn() would be appropriate. And you might consider taking out the "error = -EAGAIN" and the "break". When this occurs it doesn't mean that devices were suspended in the wrong order; it means that the ordering of the parent pointers fails to match the ordering of dpm_active. The only way for this to happen is if the parent pointers are messed up by device_move() -- dpm_active will still be correct. The rest of the patch looks fine. Alan Stern -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/