Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755673AbcC2CkZ (ORCPT ); Mon, 28 Mar 2016 22:40:25 -0400 Received: from mail-oi0-f47.google.com ([209.85.218.47]:36384 "EHLO mail-oi0-f47.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753812AbcC2CkU (ORCPT ); Mon, 28 Mar 2016 22:40:20 -0400 MIME-Version: 1.0 From: Andy Lutomirski Date: Mon, 28 Mar 2016 19:39:59 -0700 Message-ID: Subject: i915 4.5 bugfix backport and release management issue? To: DRI , Dave Airlie , Matt Roper , Jani Nikula , Daniel Vetter , "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: 1979 Lines: 52 Hi all- 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. Can you please: a) figure out what happened and send a backport of whatever needs to be backported to stable@vger.kernel.org. b) do whatever needs to be done so this doesn't happen again c) teach the i915 CI system to test Linus' tree as-is in addition to the development trees. Linus' tree and the versions of i915 in actual released versions of Linux are supposed to work. I hate to nag, but this is at least the third time I've noticed weird release management issues in i915. I tripped on a regression a few releases ago that was known to the i915 team and fixed but the fix wasn't actually queued up for the current release. Before that, I tripped on a regression caused by an intentional behavior change that was folded in to a merge commit, making it essentially impossible to bisect and making it pointlessly hard to understand what was going on even once I found the offending code. Thanks, Andy