Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933819AbZJGQBM (ORCPT ); Wed, 7 Oct 2009 12:01:12 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1759194AbZJGQBL (ORCPT ); Wed, 7 Oct 2009 12:01:11 -0400 Received: from smtp-out002.kontent.com ([81.88.40.216]:35230 "EHLO smtp-out002.kontent.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754340AbZJGQBK (ORCPT ); Wed, 7 Oct 2009 12:01:10 -0400 From: Oliver Neukum To: Johan Hovold Subject: Re: [PATCH 5/5] opticon: Fix resume logic Date: Wed, 7 Oct 2009 18:01:58 +0200 User-Agent: KMail/1.10.3 (Linux/2.6.31-rc9-0.1-default; KDE/4.1.3; x86_64; ; ) Cc: Alan Cox , Alan Cox , Alan Stern , greg@kroah.com, linux-kernel@vger.kernel.org, linux-usb@vger.kernel.org References: <20091006145413.9431.47083.stgit@localhost.localdomain> <20091006232331.5684bbee@lxorguk.ukuu.org.uk> <20091007155602.GB12396@localhost> In-Reply-To: <20091007155602.GB12396@localhost> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200910071801.59423.oliver@neukum.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1192 Lines: 30 Am Mittwoch, 7. Oktober 2009 17:56:02 schrieb Johan Hovold: > On Tue, Oct 06, 2009 at 11:23:31PM +0100, Alan Cox wrote: > > On Tue, 6 Oct 2009 23:12:17 +0200 > > > > Oliver Neukum wrote: > > > Am Dienstag, 6. Oktober 2009 17:06:57 schrieb Alan Cox: > > > > Opticon now takes the right mutex to check the port status but the > > > > status check is done wrongly for the modern serial code, so fix it. > > > > > > As Alan Stern noticed, it seems like we have an ab-ba deadlock here > > > between open and resume regarding pm_mutex and port->mutex. > > > > Oh well I guess someone with hardware will have to fix that. > > > > Do we actually need a separate pm_mutex anyway ? > > The pm_mutex is actually not aquired during open (and Alan Stern just > confirmed that), so there is no dead-lock with port->mutex. This is currently true, but will no longer be true if autosuspend is implemented for this driver. Regards Oliver -- 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/