From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753951AbcCKJOA (ORCPT ); Fri, 11 Mar 2016 04:14:00 -0500 Received: from mail-wm0-f66.google.com ([74.125.82.66]:35721 "EHLO mail-wm0-f66.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753395AbcCKJNG (ORCPT ); Fri, 11 Mar 2016 04:13:06 -0500 Date: Fri, 11 Mar 2016 10:13:01 +0100 From: Ingo Molnar To: Toshi Kani Cc: bp@suse.de, hpa@zytor.com, tglx@linutronix.de, mcgrof@suse.com, jgross@suse.com, paul.gortmaker@windriver.com, x86@kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 2/2] x86/mtrr: Refactor PAT initialization code Message-ID: <20160311091301.GA11595@gmail.com> References: <1457671546-13486-1-git-send-email-toshi.kani@hpe.com> <1457671546-13486-3-git-send-email-toshi.kani@hpe.com> <20160311090140.GA4873@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20160311090140.GA4873@gmail.com> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org * Ingo Molnar wrote: > > * Toshi Kani wrote: > > > MTRR manages PAT initialization as it implements a rendezvous > > handler that initializes PAT as part of MTRR initialization. > > > > When CPU does not support MTRR, ex. qemu32 virtual CPU, MTRR > > simply skips PAT init, which causes PAT left enabled without > > initialization. [...] > > What practical effects does this have to the user? Does the kernel crash? Btw., I find this omission _highly_ annoying: describing what negative effects a bug _causes in practice_ is the most important part of a changelog. How on earth can an experienced contributor omit such an important component from a patch description? Most readers of changelogs couldn't care less about technical details of how the bug is fixed (of course others will read it so it's nice to have too), but what symptoms a bug causes, how serious is it, whether it should be backported are like super important compared to everything else you wrote - and both the description and the changelogs are totally silent on those topics ... I've seen this in other PAT patches - please try to improve this. Thanks, Ingo