From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751639AbcFSWKQ (ORCPT ); Sun, 19 Jun 2016 18:10:16 -0400 Received: from bedivere.hansenpartnership.com ([66.63.167.143]:56736 "EHLO bedivere.hansenpartnership.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751403AbcFSWKM (ORCPT ); Sun, 19 Jun 2016 18:10:12 -0400 Message-ID: <1466373202.2280.3.camel@HansenPartnership.com> Subject: Re: [Intel-gfx] Bad flicker on skylake HQD due to code in the 4.7 merge window From: James Bottomley To: Jani Nikula , Daniel Vetter Cc: intel-gfx , dri-devel , linux-kernel , Rodrigo Vivi Date: Sun, 19 Jun 2016 14:53:22 -0700 In-Reply-To: <1466204815.2199.2.camel@HansenPartnership.com> 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> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.16.5 Mime-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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-git > > -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. James