From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753383Ab1LLXis (ORCPT ); Mon, 12 Dec 2011 18:38:48 -0500 Received: from www.linutronix.de ([62.245.132.108]:55470 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751346Ab1LLXir (ORCPT ); Mon, 12 Dec 2011 18:38:47 -0500 Date: Tue, 13 Dec 2011 00:38:44 +0100 (CET) From: Thomas Gleixner To: Andres Salomon cc: Jens Rottmann , linux-kernel@vger.kernel.org, linux-geode@lists.infradead.org Subject: Re: IRQF_TIMER | IRQF_SHARED ? In-Reply-To: <20111212123131.502be350@queued.net> Message-ID: References: <4EE620A5.7080402@LiPPERTEmbedded.de> <20111212123131.502be350@queued.net> User-Agent: Alpine 2.02 (LFD 1266 2009-07-14) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII X-Linutronix-Spam-Score: -1.0 X-Linutronix-Spam-Level: - X-Linutronix-Spam-Status: No , -1.0 points, 5.0 required, ALL_TRUSTED=-1,SHORTCIRCUIT=-0.0001 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 12 Dec 2011, Andres Salomon wrote: > On Mon, 12 Dec 2011 16:41:25 +0100 > Jens Rottmann wrote: > > > But I did not fail to notice that _none_ of the code in > > drivers/clocksource/ uses IRQF_SHARED, obviously this must be > > deliberate. > > Hm, maybe tglx knows? For my part, I don't think it would be a > problem, but I can imagine the reason for not sharing being clock drift > or something to that effect. No, you can share a timer irq. The other drivers don't have the SHARED flag set because they are on exclusive irq lines, which is the sane thing to do. shared irqs suck and you figure that out once you try to use that shared timer irq on a preempt-rt enabled kernel. Thanks, tglx