From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ben Widawsky Subject: Re: [PATCH] drm/i915: dump even more into the error_state Date: Fri, 3 Feb 2012 18:23:10 -0800 Message-ID: <20120204022309.GA7236@snipes.kumite> References: <1328131605-20174-1-git-send-email-daniel.vetter@ffwll.ch> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from cloud01.chad-versace.us (184-106-247-128.static.cloud-ips.com [184.106.247.128]) by gabe.freedesktop.org (Postfix) with ESMTP id B80219E75B for ; Fri, 3 Feb 2012 18:23:22 -0800 (PST) Content-Disposition: inline In-Reply-To: <1328131605-20174-1-git-send-email-daniel.vetter@ffwll.ch> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: intel-gfx-bounces+gcfxdi-intel-gfx=m.gmane.org@lists.freedesktop.org Errors-To: intel-gfx-bounces+gcfxdi-intel-gfx=m.gmane.org@lists.freedesktop.org To: Daniel Vetter Cc: Intel Graphics Development List-Id: intel-gfx@lists.freedesktop.org On Wed, Feb 01, 2012 at 10:26:45PM +0100, Daniel Vetter wrote: > Chris Wilson and me have again stared at funny error states and it's > been pretty clear from the start that something was seriously amiss. > The seqnos last seen by the cpu were a few hundred behind those that > the gpu could have possibly emitted last before it died ... > > Chris now tracked it down (hopefully, definit verdict's still out), > but in hindsight we'd have found the bug by simply dumping the cpu > side tracking of the ring head and tail registers. > > Fix this and prevent an identical time-waster in the future. > > Because the hangs always involved semaphores in one way or another, > we've tried to dump the mbox registers, but couldn't find any > inconsistencies. Still, dump them too. How about we only do this if semaphores are actually enabled? I think that will eliminate potential confusion.