Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755495AbYKJQyT (ORCPT ); Mon, 10 Nov 2008 11:54:19 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754174AbYKJQyB (ORCPT ); Mon, 10 Nov 2008 11:54:01 -0500 Received: from mx2.suse.de ([195.135.220.15]:51815 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753829AbYKJQyA (ORCPT ); Mon, 10 Nov 2008 11:54:00 -0500 Date: Mon, 10 Nov 2008 17:53:58 +0100 Message-ID: From: Takashi Iwai To: "Matt Fleming" Cc: "Will Newton" , linux-kernel@vger.kernel.org, tglx@linutronix.de, mingo@elte.hu, venkatesh.pallipadi@intel.com Subject: Re: [PATCH 2/3] HPET: Enter hpet_interrupt_handler with interrupts disabled In-Reply-To: <5ff4a1e50811021423l795dd059v3d1667fb4bc9539c@mail.gmail.com> References: <1225641860-6120-1-git-send-email-mjf@gentoo.org> <1225641860-6120-2-git-send-email-mjf@gentoo.org> <87a5b0800811021335nfe6202fwc00681ec96d9816c@mail.gmail.com> <5ff4a1e50811021423l795dd059v3d1667fb4bc9539c@mail.gmail.com> User-Agent: Wanderlust/2.12.0 (Your Wildest Dreams) SEMI/1.14.6 (Maruoka) FLIM/1.14.7 (=?ISO-8859-4?Q?Sanj=F2?=) APEL/10.6 Emacs/22.3 (x86_64-suse-linux-gnu) MULE/5.0 (SAKAKI) MIME-Version: 1.0 (generated by SEMI 1.14.6 - "Maruoka") Content-Type: text/plain; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 866 Lines: 26 At Sun, 2 Nov 2008 22:23:13 +0000, Matt Fleming wrote: > > 2008/11/2 Will Newton : > > > > Combining IRQF_DISABLED and IRQF_SHARED does not reliably disable > > interrupts in the handler. Perhaps IRQF_SHARED should be removed at > > the same time? > > > > I didn't know that. Under what conditions is it unreliable? The kernel checks IRQF_DISABLED bit of only the first handler even if multiple handlers are assigned to a single IRQ line. Thus, if another handler without IRQF_DISABLED has been already registered before yours, your IRQF_DISABLED is ignored. See kernel/irq/handle.c. Takashi -- 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/