From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dmitry Torokhov Subject: Re: [linux-pm] wacom + runtime PM = AA deadlock Date: Mon, 13 Sep 2010 13:28:31 -0700 Message-ID: <201009131328.33600.dmitry.torokhov@gmail.com> References: Mime-Version: 1.0 Content-Type: Text/Plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Return-path: Received: from mail-px0-f174.google.com ([209.85.212.174]:65501 "EHLO mail-px0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751794Ab0IMU2q (ORCPT ); Mon, 13 Sep 2010 16:28:46 -0400 In-Reply-To: Sender: linux-input-owner@vger.kernel.org List-Id: linux-input@vger.kernel.org To: Alan Stern Cc: Oliver Neukum , Jiri Slaby , pingc@wacom.com, linux-pm , Linux kernel mailing list , linux-input@vger.kernel.org On Monday, September 13, 2010 01:02:16 pm Alan Stern wrote: > On Mon, 13 Sep 2010, Oliver Neukum wrote: > > Am Montag, 13. September 2010, 17:17:54 schrieb Alan Stern: > > > On Mon, 13 Sep 2010, Oliver Neukum wrote: > > > > PM in this driver looks broken. Please try this. > > > > > > > > In short you want to drop the PM reference and depend on remote > > > > wakeup and busy marking for this driver. Currently it gets a > > > > reference on every open() but never drops it. > > > > > > > > For locking you depend on the PM core's internal lock. You simply > > > > make sure you have a PM reference during open() and close() > > > > > > Is there any point in resuming the device during close() just in order > > > to kill the interrupt URB? It seems counterproductive -- if the device > > > had been suspended then there wouldn't be any interrupt URB to kill in > > > the first place. > > > > Suppose the device does not support remote wakeup. It would never > > be autosuspended while it is open, but simply resetting the flag > > would never reach the PM layer. > > Whoops, that's right. I didn't see the assignment to > needs_remote_wakeup. > > How come wacom_open doesn't check to see if wacom->open is already set? No need - input core will not call dev->open() twice. -- Dmitry