Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758768AbbFAGXP (ORCPT ); Mon, 1 Jun 2015 02:23:15 -0400 Received: from smtprelay.restena.lu ([158.64.1.62]:48294 "EHLO smtprelay.restena.lu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753064AbbFAGXB (ORCPT ); Mon, 1 Jun 2015 02:23:01 -0400 Date: Mon, 1 Jun 2015 08:22:27 +0200 From: Bruno =?UTF-8?B?UHLDqW1vbnQ=?= To: Darren Hart Cc: Michael Marineau , Bjorn Helgaas , platform-driver-x86@vger.kernel.org, "linux-kernel@vger.kernel.org" , Petri Hodju , Matthew Garrett , "linux-pci@vger.kernel.org" Subject: Re: [Patch v3] apple-gmux: lock iGP IO to protect from vgaarb changes Message-ID: <20150601082227.01663ac8@pluto.restena.lu> In-Reply-To: <20150529163650.GA94698@vmdeb7> References: <20150305232038.1873d380@neptune.home> <20150306174254.GB19001@vmdeb7> <20150307011546.0050279d@neptune.home> <20150309225238.0b9ced4e@neptune.home> <20150311223445.6af76f7c@neptune.home> <20150527044749.GB21644@fury.dvhart.com> <20150527081323.35a3cf88@pluto.restena.lu> <20150529163650.GA94698@vmdeb7> X-Mailer: Claws Mail 3.11.1 (GTK+ 2.24.27; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1128 Lines: 25 On Fri, 29 May 2015 18:36:50 +0200 Darren Hart wrote: > > Making sure to lock only the intel GPU when present and especially protecting > > against nvidia driver will be hard if legacy-IO is being processed by a hidden > > device! > > Ugh indeed. Worst case we can special case via dmi strings. Is this Apple device > significantly different from others? Bruno, what are you testing on? I only own a pretty old MacBook Air with just NVIDIA IGP and had to rely on BUG reports and testing from affected users. Not doing anything on apple-gmux when only a single GPU is visible should be easy, but denying any vgaarb operation when Intel IGP is hidden and just discrete GPU present is much harder (if one does not want to risk opening the next can of worms). DMI based special-casing would work but will it uncover the next issue with the same device configured differently? Bruno -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/