Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753322AbdCFMGn (ORCPT ); Mon, 6 Mar 2017 07:06:43 -0500 Received: from mail.fireflyinternet.com ([109.228.58.192]:51710 "EHLO fireflyinternet.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S932075AbdCFMGW (ORCPT ); Mon, 6 Mar 2017 07:06:22 -0500 X-Default-Received-SPF: pass (skip=forwardok (res=PASS)) x-ip-name=78.156.65.138; Date: Mon, 6 Mar 2017 11:47:58 +0000 From: Chris Wilson To: Pavel Machek , kernel list , daniel.vetter@intel.com, jani.nikula@linux.intel.com, intel-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org Subject: Re: [regression] Re: 4.11-rc0, thinkpad x220: GPU hang Message-ID: <20170306114758.GT5997@nuc-i3427.alporthouse.com> Mail-Followup-To: Chris Wilson , Pavel Machek , kernel list , daniel.vetter@intel.com, jani.nikula@linux.intel.com, intel-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org References: <20170228143453.GA11914@amd> <20170228150222.GU10304@nuc-i3427.alporthouse.com> <20170305230150.GA15063@amd> <20170306111528.GR5997@nuc-i3427.alporthouse.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20170306111528.GR5997@nuc-i3427.alporthouse.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1295 Lines: 34 On Mon, Mar 06, 2017 at 11:15:28AM +0000, Chris Wilson wrote: > On Mon, Mar 06, 2017 at 12:01:51AM +0100, Pavel Machek wrote: > > Hi! > > > > > > mplayer stopped working after a while. Dmesg says: > > > > > > > > [ 3000.266533] cdc_ether 2-1.2:1.0 usb0: register 'cdc_ether' at > > > > Now I'm pretty sure it is a regression in v4.11-rc0. Any ideas what to > > try? Bisect will be slow and nasty :-(. > > I came the conclusion that #99671 is the ring HEAD overtaking the TAIL, > and under the presumption that your bug matches (as the symptoms do): > > diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.c b/drivers/gpu/drm/i915/intel_ringbuffer.c > index 4ffa35faff49..62e31a7438ac 100644 > --- a/drivers/gpu/drm/i915/intel_ringbuffer.c > +++ b/drivers/gpu/drm/i915/intel_ringbuffer.c > @@ -782,10 +782,10 @@ static void i9xx_submit_request(struct drm_i915_gem_request *request) > { > struct drm_i915_private *dev_priv = request->i915; > > - i915_gem_request_submit(request); > - > GEM_BUG_ON(!IS_ALIGNED(request->tail, 8)); > I915_WRITE_TAIL(request->engine, request->tail); > + > + i915_gem_request_submit(request); Hmm. request->tail is not set until i915_gem_request_submit() Uh oh. -Chris -- Chris Wilson, Intel Open Source Technology Centre