From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757573Ab2DFVbs (ORCPT ); Fri, 6 Apr 2012 17:31:48 -0400 Received: from mail-wg0-f44.google.com ([74.125.82.44]:61506 "EHLO mail-wg0-f44.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751861Ab2DFVbr (ORCPT ); Fri, 6 Apr 2012 17:31:47 -0400 Message-ID: <4F7F60BF.9070500@suse.cz> Date: Fri, 06 Apr 2012 23:31:43 +0200 From: Jiri Slaby User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:13.0) Gecko/20120404 Thunderbird/13.0a2 MIME-Version: 1.0 To: Chris Wilson CC: Jiri Slaby , Keith Packard , dri-devel@lists.freedesktop.org, LKML , daniel@ffwll.ch, Thomas Gleixner Subject: Re: i915_driver_irq_handler: irq 42: nobody cared [generic IRQ handling broken?] References: <4F717CE3.4040206@suse.cz> <4F717D80.9040207@suse.cz> <4F758400.3080907@suse.cz> <1333104359_155028@CP5-2952> <4F75A303.3030409@suse.cz> <1333110296_156038@CP5-2952> In-Reply-To: <1333110296_156038@CP5-2952> X-Enigmail-Version: 1.4 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 03/30/2012 02:24 PM, Chris Wilson wrote: > On Fri, 30 Mar 2012 14:11:47 +0200, Jiri Slaby wrote: >> On 03/30/2012 12:45 PM, Chris Wilson wrote: >>> On Fri, 30 Mar 2012 11:59:28 +0200, Jiri Slaby wrote: >>>> I don't know what to dump more, because iir is obviously zero too. What >>>> other sources of interrupts are on the (G33) chip? >>> >>> IIR is the master interrupt, with chained secondary interrupt statuses. >>> If IIR is 0, the interrupt wasn't raised by the GPU. >> >> This does not make sense, the handler does something different. Even if >> IIR is 0, it still takes a look at pipe stats. > > That was introduced in 05eff845a28499762075d3a72e238a31f4d2407c to close > a race where the pipestat triggered an interrupt after we processed the > secondary registers and before reseting the primary. > > But the basic premise that we should only enter the interrupt handler > with IIR!=0 holds (presuming non-shared interrupt lines such as MSI). Ok, this behavior is definitely new. I get several "nobody cared" about this interrupt a week. This never used to happen. And something weird emerges in /proc/interrupts when this happens: 42: 1003292 1212890 PCI-MSI-edge �s����:0000:00:02.0 instead of 42: 1006715 1218472 PCI-MSI-edge i915@pci:0000:00:02.0 It very looks like the generic IRQ handling code is broken. Like it frees/corrupts irq_desc and then as well calls random handlers. Suspend/resume cycle helps in this case and "i915@pci:0000:00:02.0" is back in /proc/interrupts as can be seen above. Running 3.3.0-next-20120326_64+ now. thanks, -- js suse labs