Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755943AbYKCNsX (ORCPT ); Mon, 3 Nov 2008 08:48:23 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754114AbYKCNsP (ORCPT ); Mon, 3 Nov 2008 08:48:15 -0500 Received: from mail.atmel.fr ([81.80.104.162]:58564 "EHLO atmel-es2.atmel.fr" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755265AbYKCNsP (ORCPT ); Mon, 3 Nov 2008 08:48:15 -0500 Message-ID: <490F00F5.3020709@atmel.com> Date: Mon, 03 Nov 2008 14:47:33 +0100 From: Nicolas Ferre Organization: atmel User-Agent: Thunderbird 2.0.0.17 (Windows/20080914) MIME-Version: 1.0 To: David Brownell CC: Peter Zijlstra , Pierre Ossman , lkml , Ingo Molnar , Russell King , Nicolas Ferre , Andrew Victor , Thomas Gleixner Subject: Re: [patch 2.6.28-rc2] at91_mci: workaround lockdep References: <200810271426.27110.david-b@pacbell.net> <1225213442.15763.20.camel@lappy.programming.kicks-ass.net> <200810281022.42803.david-b@pacbell.net> In-Reply-To: <200810281022.42803.david-b@pacbell.net> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1550 Lines: 38 David Brownell : > On Tuesday 28 October 2008, Peter Zijlstra wrote: >> On Mon, 2008-10-27 at 14:26 -0700, David Brownell wrote: >>> From: David Brownell >>> >>> Lockdep reported a problem in the at91_mci driver ... in this case, the >>> issue is with lockdep, not with the driver. ... >>> >>> When __flush_dcache_aliases() returns -- inlined into flush_dcache_page(), >>> above -- it re-enables IRQs ... since that evidently may only be called with >>> IRQs enabled. That's OK since the (unshared) IRQ handler doesn't ask for IRQs >>> to be disabled. Except ... that lockdep went and disabled them, then went on >>> to complains about the breakage *it* caused! >>> >>> Workaround: depend on LOCKDEP=n ... >> In all previous such cases it was deemed the IRQ handler should deal >> with whatever it gets. > > In which case I'll wait until someone changes that IRQ handler (or that > ARM MM utility, or lockdep), and give up using AT91 platforms for sanity > testing kernel changes; lockdep is important, when it doesn't lie. Changing IRQ handler in this driver... seem to be a big work. Well, Dave, I tend to acknowledge your patch above as the IRQ for MCI is indeed a dedicated line (no need for IRQF_SHARED). Are you ok with this ? Regards, -- Nicolas Ferre -- 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/