From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751964AbXC0IO5 (ORCPT ); Tue, 27 Mar 2007 04:14:57 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753023AbXC0IO5 (ORCPT ); Tue, 27 Mar 2007 04:14:57 -0400 Received: from gate.crashing.org ([63.228.1.57]:36585 "EHLO gate.crashing.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752318AbXC0IOz (ORCPT ); Tue, 27 Mar 2007 04:14:55 -0400 Subject: Re: [PATCH] genirq: do not mask interrupts by default From: Benjamin Herrenschmidt To: Ingo Molnar Cc: Andrew Morton , Thomas Gleixner , Paul Mackerras , Linux Kernel list , Linus Torvalds In-Reply-To: <20070327073227.GA26457@elte.hu> References: <200702161759.l1GHxsO8010669@hera.kernel.org> <1174972037.5329.5.camel@localhost.localdomain> <1174972685.5329.12.camel@localhost.localdomain> <20070327073227.GA26457@elte.hu> Content-Type: text/plain Date: Tue, 27 Mar 2007 18:04:24 +1000 Message-Id: <1174982665.14065.5.camel@localhost.localdomain> Mime-Version: 1.0 X-Mailer: Evolution 2.10.0 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 2007-03-27 at 09:32 +0200, Ingo Molnar wrote: > * Benjamin Herrenschmidt wrote: > > > Note that I'm not opposed to the change at all, I think it's a good > > idea, I'm just worried I'm discovering it a bit late and I've seen > > PICs broken in some many colorful ways that I'm a bit worried... Oh > > well... > > This change does not really change irq-flow semantics, what it does is > that disable_irq()'s effect is delayed. The irq controller does not have > to re-assert the irq, we've got the soft-resend mechanism. What am i > missing? Are you worried about this change causing actual breakage? (and > i'm sorry about not having Cc:-ed you explicitly, i could have sworn you > were included in that discussion but apparently not!) I'm worried about some broken controllers I know of that might indeed swallow the interrupt if it occurs, we ack it, then disable it, and later on re-enable it... I think the main case I have in mind (pmac-pic) has the necessary retrigger all over the place but there is definitely a change in the flow of disabling/enabling here. Anyway, I'll run some tests tomorrow and make noise if I find something broken, though I can't test the various embedded thingies in arch/powerpc. Ben.