Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754125AbcC3IpO (ORCPT ); Wed, 30 Mar 2016 04:45:14 -0400 Received: from mail-ob0-f169.google.com ([209.85.214.169]:33781 "EHLO mail-ob0-f169.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752930AbcC3IpJ (ORCPT ); Wed, 30 Mar 2016 04:45:09 -0400 MIME-Version: 1.0 X-Originating-IP: [2a02:168:56b5:0:ac27:b86c:7764:9429] In-Reply-To: References: Date: Wed, 30 Mar 2016 10:44:35 +0200 Message-ID: Subject: Re: i915 4.5 bugfix backport and release management issue? From: Daniel Vetter To: Andy Lutomirski Cc: DRI , Dave Airlie , Matt Roper , Jani Nikula , "linux-kernel@vger.kernel.org" , intel-gfx Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2457 Lines: 56 On Tue, Mar 29, 2016 at 6:16 PM, Andy Lutomirski wrote: > On Tue, Mar 29, 2016 at 12:49 AM, Andy Lutomirski wrote: >> On Tue, Mar 29, 2016 at 12:43 AM, Daniel Vetter wrote: >>> On Tue, Mar 29, 2016 at 4:39 AM, Andy Lutomirski wrote: >>>> AFAICT something got rather screwed up in i915 land for 4.5. >>>> >>>> $ git log --oneline --grep='Pretend cursor is always on' v4.5 >>>> drivers/gpu/drm/i915/ >>>> e2e407dc093f drm/i915: Pretend cursor is always on for ILK-style WM >>>> calculations (v2) >>>> >>>> $ git log --oneline --grep='Pretend cursor is always on' v4.6-rc1 >>>> drivers/gpu/drm/i915/ >>>> e2e407dc093f drm/i915: Pretend cursor is always on for ILK-style WM >>>> calculations (v2) >>>> b2435692dbb7 drm/i915: Pretend cursor is always on for ILK-style WM >>>> calculations (v2) >>>> >>>> The two patches there are almost, but not quite, the same thing, which >>>> makes me wonder how they both ended up in Linus' tree without an >>>> obvious merge conflict. >>>> >>>> I have no idea what caused this. However, I think (on very little >>>> inspection, but it's consistent with problems I have with 4.5 on my >>>> laptop) that the first one is an *incorrect* fix for a regression in >>>> 4.5 and the second is a correct fix for the same regression. 4.6-rc1 >>>> seems okay. >>>> >>>> I reported the regression and everyone involved has known about it for >>>> weeks. Nonetheless, 4.5 final is busted. >>> >>> Quoting from e2e407dc093f >>> >>> "(cherry picked from commit b2435692dbb709d4c8ff3b2f2815c9b8423b72bb)" >>> >>> i.e. this is intentionally twice in the history. We started to soak >>> bugfixes in -next and then cherry pick them because we had too much >>> fun with things blowing up, and also too much fun with really messy >>> conflicts. It's not a botched patch in 4.5 or anything else nefarious >>> at all. >> >> Bah, sorry, I read it wrong. They have the same final state but they >> were on different bases. I somehow reversed this in my head and >> thought they had the same initial state and different final states. >> > > Also, sorry for the excessive diatribe. I plead sleepiness and > mis-reading of code. Thanks. We really appreciate friendly discussions here on intel-gfx, the technical challenges are hard enough as is. -Daniel -- Daniel Vetter Software Engineer, Intel Corporation +41 (0) 79 365 57 48 - http://blog.ffwll.ch