From mboxrd@z Thu Jan 1 00:00:00 1970 From: Chris Wilson Subject: Re: [PATCH] drm/i915: Mask the ring->head offset using the ring->size Date: Wed, 08 Feb 2012 12:49:04 +0000 Message-ID: References: <1320793992-2891-1-git-send-email-chris@chris-wilson.co.uk> <20120117105927.GI4093@phenom.ffwll.local> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from mga11.intel.com (mga11.intel.com [192.55.52.93]) by gabe.freedesktop.org (Postfix) with ESMTP id 68116A02C1 for ; Wed, 8 Feb 2012 04:49:10 -0800 (PST) In-Reply-To: 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-gfx@lists.freedesktop.org, stable@kernel.org List-Id: intel-gfx@lists.freedesktop.org On Tue, 17 Jan 2012 11:14:04 +0000, Chris Wilson wrote: > On Tue, 17 Jan 2012 11:59:27 +0100, Daniel Vetter wrote: > > I guess this is just the usual "snb doesn't like being pushed to hard bug" > > resulting in random crashes with confusing error_states. So I think I'll > > drop this. Correct? > > I could find no other reason for this to have any effect other than the > hw not playing fair so don't apply it until some one else starts > experiencing random hangs on their SNB and can confirm whether this > patch helps. The news is that the hw is indeed not playing fair, and we have some substantial evidence that demonstrates the cause here is the autoreported position of the head is completely bogus on SNB+. See https://bugs.freedesktop.org/show_bug.cgi?id=45492 -Chris -- Chris Wilson, Intel Open Source Technology Centre