From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752397AbcFWM7x (ORCPT ); Thu, 23 Jun 2016 08:59:53 -0400 Received: from mga11.intel.com ([192.55.52.93]:54245 "EHLO mga11.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751357AbcFWM7w convert rfc822-to-8bit (ORCPT ); Thu, 23 Jun 2016 08:59:52 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.26,509,1459839600"; d="scan'208";a="1008148925" From: Jani Nikula To: Steven Newbury , James Bottomley , Daniel Vetter Cc: intel-gfx , linux-kernel , dri-devel , Rodrigo Vivi Subject: Re: [Intel-gfx] Bad flicker on skylake HQD due to code in the 4.7 merge window In-Reply-To: <1466686369.6831.1.camel@snewbury.org.uk> Organization: Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo References: <1464638381.2240.3.camel@HansenPartnership.com> <871t4ibr7k.fsf@intel.com> <1464701638.2234.1.camel@HansenPartnership.com> <87mvmp9z03.fsf@intel.com> <1466111747.2311.1.camel@HansenPartnership.com> <1466112547.2311.3.camel@HansenPartnership.com> <1466116932.2257.4.camel@HansenPartnership.com> <20160617072826.GI23520@phenom.ffwll.local> <87vb18uef2.fsf@intel.com> <1466204815.2199.2.camel@HansenPartnership.com> <1466373202.2280.3.camel@HansenPartnership.com> <1466686369.6831.1.camel@snewbury.org.uk> User-Agent: Notmuch/0.22+12~gbdd9442 (http://notmuchmail.org) Emacs/24.4.1 (x86_64-pc-linux-gnu) Date: Thu, 23 Jun 2016 15:59:49 +0300 Message-ID: <87r3bohxh6.fsf@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 23 Jun 2016, Steven Newbury wrote: > [ Unknown signature status ] > On Sun, 2016-06-19 at 14:53 -0700, James Bottomley wrote: >> On Fri, 2016-06-17 at 16:06 -0700, James Bottomley wrote: >> > On Fri, 2016-06-17 at 16:34 +0300, Jani Nikula wrote: >> > > On Fri, 17 Jun 2016, Daniel Vetter wrote: >> > > > On Thu, Jun 16, 2016 at 03:42:12PM -0700, James Bottomley >> > > > wrote: >> > > > > On Thu, 2016-06-16 at 14:29 -0700, James Bottomley wrote: >> > > > > > On Thu, 2016-06-16 at 23:24 +0200, Daniel Vetter wrote: >> > > > > > > I guess we'll need the bisect on this one to make >> > > > > > > progress. >> > > > > > >> > > > > > Sigh, I was afraid that might be the next step. >> > > > > >> > > > > OK, I have a curious data point.  I assumed the problem would >> > > > > be >> > > > > somewhere in the drm update, so I started bisecting that at >> > > > > the >> > > > > top.  >> > > > >  However, the top most commit: >> > > > > >> > > > > commit 1d6da87a3241deb13d073c4125d19ed0e5a0c62c >> > > > > Merge: 1f40c49 a39ed68 >> > > > > Author: Linus Torvalds >> > > > > Date:   Mon May 23 11:48:48 2016 -0700 >> > > > > >> > > > >     Merge branch 'drm-next' of >> > > > > git://people.freedesktop.org/~airlied/linux >> > > > > >> > > > > Isn't actually bad.  There's no flicker here, so whatever >> > > > > caused >> > > > > the >> > > > > problem came from some update after this. >> > > > >> > > > There was a fixes pull after this. Might be worth it to >> > > > restrict >> > > > to >> > > > just >> > > > the i915 changes, which are just >> > > > 5b4fd5b1111b1230cd037..157d2c7fad0863222 >> > > > >> > > > Looking at those nothing seems to stick out which might explain >> > > > what's >> > > > happening for you. >> > >> > OK, so just on the firmware, the system seems less flickery with >> > the >> > new 1.4.3 UEFI, so I'm starting to think it is a Skylake errata  >> > issue.  The flicker isn't gone for good, but seems to be reboot  >> > dependent (it's there in some boots, but gone on a reboot). >> > >> > > This should be easy enough to try before bisecting: >> > > http://patchwork.freedesktop.org/patch/msgid/1466162081-12042-1-g >> > > it >> > > -s >> > > end-email-mika.kahola@intel.com >> > >> > Applying this didn't seem to make a difference: still there on >> > some  >> > and gone on other reboots. >> >> OK, my candidate bad commit is this one: >> >> commit a05628195a0d9f3173dd9aa76f482aef692e46ee >> Author: Ville Syrjälä >> Date:   Mon Apr 11 10:23:51 2016 +0300 >> >>     drm/i915: Get panel_type from OpRegion panel details >> >> After being more careful about waiting to identify flicker, this one >> seems to be the one the bisect finds.  I'm now running v4.7-rc3 with >> this one reverted and am currently seeing no flicker problems.  It >> is, >> however, early days because the flicker can hide for long periods, so >> I >> 'll wait until Monday evening and a few reboots before declaring >> victory. >> >>  > I'm seeing this on my IvyBridge.  I'll try reverting the commit here > too, to see if it's the same issue. IvyBridge doesn't have low vswing for eDP. If reverting helps, it's a different failure mode. BR, Jani. -- Jani Nikula, Intel Open Source Technology Center