From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jiri Slaby Subject: Re: i915_driver_irq_handler: irq 42: nobody cared [generic IRQ handling broken?] Date: Fri, 06 Apr 2012 23:31:43 +0200 Message-ID: <4F7F60BF.9070500@suse.cz> 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> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: In-Reply-To: <1333110296_156038@CP5-2952> Sender: linux-kernel-owner@vger.kernel.org To: Chris Wilson Cc: Jiri Slaby , Keith Packard , dri-devel@lists.freedesktop.org, LKML , daniel@ffwll.ch, Thomas Gleixner List-Id: dri-devel@lists.freedesktop.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 wro= te: >>>> 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 statu= ses. >>> 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. >=20 > That was introduced in 05eff845a28499762075d3a72e238a31f4d2407c to cl= ose > a race where the pipestat triggered an interrupt after we processed t= he > secondary registers and before reseting the primary. >=20 > But the basic premise that we should only enter the interrupt handler > with IIR!=3D0 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 =EF=BF=BDs=EF=BF=BD=EF=BF= =BD=EF=BF=BD=EF=BF=BD: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, --=20 js suse labs