Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757128AbcC2QQc (ORCPT ); Tue, 29 Mar 2016 12:16:32 -0400 Received: from mail-ob0-f181.google.com ([209.85.214.181]:36482 "EHLO mail-ob0-f181.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751724AbcC2QQa (ORCPT ); Tue, 29 Mar 2016 12:16:30 -0400 MIME-Version: 1.0 In-Reply-To: References: From: Andy Lutomirski Date: Tue, 29 Mar 2016 09:16:09 -0700 Message-ID: Subject: Re: i915 4.5 bugfix backport and release management issue? To: Daniel Vetter Cc: DRI , Dave Airlie , Matt Roper , Jani Nikula , "linux-kernel@vger.kernel.org" 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: 2112 Lines: 49 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. --Andy