Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754807AbYKQWoc (ORCPT ); Mon, 17 Nov 2008 17:44:32 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753737AbYKQWoP (ORCPT ); Mon, 17 Nov 2008 17:44:15 -0500 Received: from tim.rpsys.net ([194.106.48.114]:52348 "EHLO tim.rpsys.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753662AbYKQWoP (ORCPT ); Mon, 17 Nov 2008 17:44:15 -0500 Subject: Re: [PATCH] leds: Fix locking for WM8350 From: Richard Purdie To: Mark Brown Cc: Pavel Machek , linux-kernel@vger.kernel.org In-Reply-To: <20081115191414.GA12907@opensource.wolfsonmicro.com> References: <1226579997-3505-1-git-send-email-broonie@opensource.wolfsonmicro.com> <1226588269-17642-1-git-send-email-broonie@opensource.wolfsonmicro.com> <20081115173110.GD1523@ucw.cz> <20081115175050.GB12466@opensource.wolfsonmicro.com> <20081115185119.GA19900@elf.ucw.cz> <20081115191414.GA12907@opensource.wolfsonmicro.com> Content-Type: text/plain Date: Mon, 17 Nov 2008 15:33:15 +0000 Message-Id: <1226935995.17109.22.camel@ted> Mime-Version: 1.0 X-Mailer: Evolution 2.22.3.1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1252 Lines: 33 On Sat, 2008-11-15 at 19:14 +0000, Mark Brown wrote: > On Sat, Nov 15, 2008 at 07:51:20PM +0100, Pavel Machek wrote: > > On Sat 2008-11-15 17:50:50, Mark Brown wrote: > > > > Yes, that'd be safer though I'd be surprised to see systems that could > > > trigger it. > > > Yes, they are uncommon. They exist; SPARC, IIRC. Plus you need > > Exceptionally uncommon with the systems the WM8350 gets used with - > it's a primary PMIC for mobile devices so anything other than > uniprocessor ARM would be surprising. > > > barriers on anything SMP... Just use atomic_t. > > I was intending to do so next time I spin the patch. Andrew had some > other comments and I don't have any test systems when I'm not in the > office anyway. I've not looked in detail at the code but it looks like a maximum of a 32 bit value where you don't actually care which write succeeds as long as it takes one of the values written? I don't see why that particular variable needs any locking or to be atomic? Cheers, Richard -- 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/