From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757972Ab1LNSho (ORCPT ); Wed, 14 Dec 2011 13:37:44 -0500 Received: from mail.lippert-at.com ([62.80.22.186]:14919 "EHLO domex.lippertembedded.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1757717Ab1LNShh (ORCPT ); Wed, 14 Dec 2011 13:37:37 -0500 Message-ID: <4EE8ECF3.6000900@LiPPERTEmbedded.de> Date: Wed, 14 Dec 2011 19:37:39 +0100 From: Jens Rottmann User-Agent: Thunderbird 1.5.0.14 (Windows/20071210) MIME-Version: 1.0 To: Andres Salomon CC: Thomas Gleixner , linux-kernel@vger.kernel.org, linux-geode@lists.infradead.org Subject: Re: IRQF_TIMER | IRQF_SHARED ? References: <4EE620A5.7080402@LiPPERTEmbedded.de> <20111212123131.502be350@queued.net> <4EE77416.8090907@LiPPERTEmbedded.de> In-Reply-To: <4EE77416.8090907@LiPPERTEmbedded.de> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit X-OriginalArrivalTime: 14 Dec 2011 18:37:33.0119 (UTC) FILETIME=[7151FCF0:01CCBA8F] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Jens Rottmann schrieb: > Andres Salomon schrieb: >> Just loading cs5535-clockevt should start the periodic timer. >> On my XO-1, IRQ 7 starts firing immediately. > Hmm, no, doesn't work. :-| In /proc/interrupts IRQ 0 gets increased, > not (in my case) IRQ 11. Update: I found that SMP-enabled kernels (like the generic one I was using) do load cs5535-clockevt fine but ignore it and keep using the pit timer instead. Responsible seems kernel/time/tick-common.c: tick_check_new_device() /* * If the cpu affinity of the device interrupt can not * be set, ignore it. */ if (!irq_can_set_affinity(newdev->irq)) goto out_bc; Looks like it has been that way for quite some time, maybe cs5535-clockevt hasn't ever worked on SMP kernels. If I turn off SMP, cs5535-clockevt replaces the pit timer and the MFGPT IRQ starts firing just as you said - at least on 3.0.9. 3.2-rc5 prefers to hang instead, looks like no timer events get generated. Sigh. I'll try to narrow it down tomorrow, but now I'm calling it a day. Cheers Jens