From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756034Ab1KWOiS (ORCPT ); Wed, 23 Nov 2011 09:38:18 -0500 Received: from mail-ww0-f42.google.com ([74.125.82.42]:45591 "EHLO mail-ww0-f42.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753521Ab1KWOiP (ORCPT ); Wed, 23 Nov 2011 09:38:15 -0500 Date: Wed, 23 Nov 2011 15:39:31 +0100 From: Daniel Vetter To: David Woodhouse Cc: Daniel Vetter , rajesh.sankaran@intel.com, Keith Packard , Matthew Garrett , intel-gfx@lists.freedesktop.org, linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org Subject: Re: [PATCH] drm/i915: By default, enable RC6 on IVB and SNB when reasonable Message-ID: <20111123143931.GE3864@phenom.ffwll.local> Mail-Followup-To: David Woodhouse , rajesh.sankaran@intel.com, Keith Packard , Matthew Garrett , intel-gfx@lists.freedesktop.org, linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org References: <1321684889-18691-1-git-send-email-keithp@keithp.com> <20111122201531.GD5547@srcf.ucam.org> <861uszfrah.fsf@sumi.keithp.com> <20111123102643.GB3864@phenom.ffwll.local> <1322056914.15493.158.camel@shinybook.infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1322056914.15493.158.camel@shinybook.infradead.org> X-Operating-System: Linux phenom 3.1.0+ User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Nov 23, 2011 at 02:01:54PM +0000, David Woodhouse wrote: > On Wed, 2011-11-23 at 11:26 +0100, Daniel Vetter wrote: > > On Tue, Nov 22, 2011 at 07:31:34PM -0800, Keith Packard wrote: > > > On Tue, 22 Nov 2011 20:15:31 +0000, Matthew Garrett wrote: > > > > > > > So the user has to choose between 5W of power saving or having dmar? And > > > > we default to giving them dmar? I think that's going to come as a > > > > surprise to people. > > > > > > You'd have to go into the BIOS to turn this on for most machines at > > > least? > > > > > > But, yeah, it seems like we should be turning DMAR off unless explicitly > > > requested; I can't understand how you'd ever need this running native on > > > the hardware. Not exactly an area I care about deeply; I've always > > > worked hard to make sure all virtualization garbage is disabled on every > > > machine I use. > > > > Problem is that we need to disable dmar on the entire box, afaics. And I > > assume that a bunch of people abusing desktop boards as servers will call > > "regression" on that. > > Hm, do you really have to disable it for the entire box, or just the > graphics? At least for the dmar+gfx+semaphores hang I can reproduce, just disabling dmar with intel_iommu=igfx_off is not good enough and iirc the same holds for the dmar+rc6 hangs reported. > Do we have a coherent erratum from Intel for the issues mentioned above > with DMAR+gfx+RC6? Afaik no errata applies to our dmar related troubles on snb. I've hoped that ppgtt would magically fix this, and it seems to help quite a bit for the semaphore hangs (but not everywhere). Couldn't yet look more into this. -Daniel -- Daniel Vetter Mail: daniel@ffwll.ch Mobile: +41 (0)79 365 57 48