Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S935389AbYCFQbP (ORCPT ); Thu, 6 Mar 2008 11:31:15 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S935280AbYCFQal (ORCPT ); Thu, 6 Mar 2008 11:30:41 -0500 Received: from pentafluge.infradead.org ([213.146.154.40]:38546 "EHLO pentafluge.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S935088AbYCFQak (ORCPT ); Thu, 6 Mar 2008 11:30:40 -0500 Date: Thu, 6 Mar 2008 08:30:32 -0800 From: Greg KH To: Adrian McMenamin Cc: Adrian McMenamin , LKML , linux-sh Subject: Re: Behaviour of device_register Message-ID: <20080306163032.GA12982@kroah.com> References: <8b67d60803051525g3aca775dmc14d1c2450b34168@mail.gmail.com> <20080305234653.GA5904@kroah.com> <8031.85.118.17.158.1204806681.squirrel@newgolddream.dyndns.info> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <8031.85.118.17.158.1204806681.squirrel@newgolddream.dyndns.info> User-Agent: Mutt/1.5.16 (2007-06-09) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1438 Lines: 32 On Thu, Mar 06, 2008 at 12:31:21PM -0000, Adrian McMenamin wrote: > On Wed, March 5, 2008 11:46 pm, Greg KH wrote: > > On Wed, Mar 05, 2008 at 11:25:48PM +0000, Adrian McMenamin wrote: > >> The observed behaviour for me is that it appears to be blocking the > >> vblank interrupt on my box (or more accurately stopping the workqueue > >> that the interrupt handler calls from running). And without the vblank > >> my bus won't process dma and so therefore the attempt to register the > >> device in question fails. > >> > >> But I can see no reason from a glance over the code why that (vblanks > >> being blocked) would be the case - have I missed something and the > >> vblanks will be blocked, or should I be looking elsewhere for the root > >> cause of this problem? > > > > device_register(), on it's own, does not touch any hardware, nor prevent > > anything else in the kernel from happening. > > > > So I think you need to look elsewhere, like into the bus that is doing > > the device_register() call :) > > > > > It turns out this is a lock contention issue. > > The code blocks waiting for a lock that will never be freed. The device_register() code blocks? Or something else? -- 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/