From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Rafael J. Wysocki" Subject: Re: [PATCH ver. 3] PM: allow for usage_count > 0 in pm_runtime_get() Date: Mon, 7 Dec 2009 21:26:49 +0100 Message-ID: <200912072126.49282.rjw@sisk.pl> References: Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: 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: Alan Stern Cc: Linux-pm mailing list List-Id: linux-pm@vger.kernel.org On Monday 07 December 2009, Alan Stern wrote: > This patch (as1308c) fixes __pm_runtime_get(). Currently the routine > will resume a device if the prior usage count was 0. But this isn't > right; thanks to pm_runtime_get_noresume() the usage count can be > positive even while the device is suspended. > > Signed-off-by: Alan Stern > > --- > > Rafael: > > This patch contains the most important part of the patch you rejected > last week, leaving out the semantic changes you didn't like. It really > does fix a bug, and it should be sent to Linus before the merge window > closes. Thanks, I'll include it into the next pull request. Rafael > Index: usb-2.6/drivers/base/power/runtime.c > =================================================================== > --- usb-2.6.orig/drivers/base/power/runtime.c > +++ usb-2.6/drivers/base/power/runtime.c > @@ -699,15 +699,15 @@ EXPORT_SYMBOL_GPL(pm_request_resume); > * @dev: Device to handle. > * @sync: If set and the device is suspended, resume it synchronously. > * > - * Increment the usage count of the device and if it was zero previously, > - * resume it or submit a resume request for it, depending on the value of @sync. > + * Increment the usage count of the device and resume it or submit a resume > + * request for it, depending on the value of @sync. > */ > int __pm_runtime_get(struct device *dev, bool sync) > { > - int retval = 1; > + int retval; > > - if (atomic_add_return(1, &dev->power.usage_count) == 1) > - retval = sync ? pm_runtime_resume(dev) : pm_request_resume(dev); > + atomic_inc(&dev->power.usage_count); > + retval = sync ? pm_runtime_resume(dev) : pm_request_resume(dev); > > return retval; > } > > >