From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753290AbbEKJUi (ORCPT ); Mon, 11 May 2015 05:20:38 -0400 Received: from mail-wg0-f44.google.com ([74.125.82.44]:33556 "EHLO mail-wg0-f44.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751018AbbEKJUg (ORCPT ); Mon, 11 May 2015 05:20:36 -0400 Date: Mon, 11 May 2015 11:22:55 +0200 From: Daniel Vetter To: Steven Rostedt Cc: Daniel Vetter , LKML , Daniel Vetter , intel-gfx , Linus Torvalds , dri-devel Subject: Re: [Intel-gfx] [WARNING 4.1-rc2] i915: Unclaimed register detected before writing to register 0xc4040 Message-ID: <20150511092255.GL15256@phenom.ffwll.local> Mail-Followup-To: Steven Rostedt , LKML , Daniel Vetter , intel-gfx , Linus Torvalds , dri-devel References: <20150507154045.5d37f1b5@gandalf.local.home> <20150508120831.489e86b1@gandalf.local.home> <20150508121810.0ffc2c9c@gandalf.local.home> <20150508125701.58ac46d0@gandalf.local.home> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20150508125701.58ac46d0@gandalf.local.home> X-Operating-System: Linux phenom 4.0.0-rc3+ User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, May 08, 2015 at 12:57:01PM -0400, Steven Rostedt wrote: > On Fri, 8 May 2015 12:18:10 -0400 > Steven Rostedt wrote: > > > On Fri, 8 May 2015 12:08:31 -0400 > > Steven Rostedt wrote: > > > > > > > Maybe it's my bios still (it is an older box). I'll just block out > > > compiling in SND_HDA_INTEL, so that it doesn't break my tests (they > > > fail on a WARNING). > > > > Hmm, right after I posted this I triggered the Call Trace again with > > > > # CONFIG_SND_HDA_INTEL is not set > > > > :-/ > > > > Now to figure out how to keep this from triggering. I may just keep > > adding a patch to hide that warning. Ok, so it's really i915 to blame for this. > Oh, I forgot to mention, that before the Call Trace, I get theses: > > > [ 673.093330] [drm:intel_uncore_check_errors] *ERROR* Unclaimed register before interrupt > [ 673.103206] [drm:intel_uncore_check_errors] *ERROR* Unclaimed register before interrupt > [ 673.139252] [drm:intel_uncore_check_errors] *ERROR* Unclaimed register before interrupt > [ 673.151323] [drm:ivybridge_set_fifo_underrun_reporting] *ERROR* uncleared fifo underrun on pipe A > [ 673.160745] [drm:intel_cpu_fifo_underrun_irq_handler] *ERROR* CPU pipe A FIFO underrun > > Mean anything? Display fifo underflow. It doesn happen very rarely when we change the configuration of cursors/overlays (because our code sucks, getting fixed). But in general I though we've curbed most of them ... How easy is this to reproduce? It would be interesting to see what the driver is doing with drm.debug=0xe, but that's a veritable firehose. You can change that modparam in /sys/modules/drm/parameters/debug at runtime and it has immediate effect. But we don't keep a running log around. Other things to check: - Is the fifo underrun always right next to to unclaimed register issue in dmesg? - i915.mmio_debug=10 or so for hopefully more information around the next splat. Has some gfx performance impact though. Thanks, Daniel -- Daniel Vetter Software Engineer, Intel Corporation http://blog.ffwll.ch