Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752411AbaGLKM4 (ORCPT ); Sat, 12 Jul 2014 06:12:56 -0400 Received: from mail-wg0-f47.google.com ([74.125.82.47]:57176 "EHLO mail-wg0-f47.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752216AbaGLKMw (ORCPT ); Sat, 12 Jul 2014 06:12:52 -0400 Date: Sat, 12 Jul 2014 12:13:02 +0200 From: Daniel Vetter To: "Tian, Kevin" Cc: Konrad Rzeszutek Wilk , Paolo Bonzini , "xen-devel@lists.xensource.com" , "airlied@linux.ie" , "intel-gfx@lists.freedesktop.org" , "linux-kernel@vger.kernel.org" , "qemu-devel@nongnu.org" , "dri-devel@lists.freedesktop.org" , "Chen, Tiejun" , "Kay, Allen M" Subject: Re: [Intel-gfx] [Xen-devel] [RFC][PATCH] gpu:drm:i915:intel_detect_pch: back to check devfn instead of check class type Message-ID: <20140712101302.GT17271@phenom.ffwll.local> Mail-Followup-To: "Tian, Kevin" , Konrad Rzeszutek Wilk , Paolo Bonzini , "xen-devel@lists.xensource.com" , "airlied@linux.ie" , "intel-gfx@lists.freedesktop.org" , "linux-kernel@vger.kernel.org" , "qemu-devel@nongnu.org" , "dri-devel@lists.freedesktop.org" , "Chen, Tiejun" , "Kay, Allen M" References: <53AA70C0.2000806@redhat.com> <20140707144917.GZ5821@phenom.ffwll.local> <53BAB569.5000709@redhat.com> <20140707175402.GS5821@phenom.ffwll.local> <53BADFC6.9060101@redhat.com> <20140707184006.GU5821@phenom.ffwll.local> <20140711062956.GP17271@phenom.ffwll.local> <20140711194206.GI23257@laptop.dumpdata.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Operating-System: Linux phenom 3.15.0-rc3+ 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 On Fri, Jul 11, 2014 at 08:30:59PM +0000, Tian, Kevin wrote: > > From: Konrad Rzeszutek Wilk [mailto:konrad.wilk@oracle.com] > > Sent: Friday, July 11, 2014 12:42 PM > > > > On Fri, Jul 11, 2014 at 08:29:56AM +0200, Daniel Vetter wrote: > > > On Thu, Jul 10, 2014 at 09:08:24PM +0000, Tian, Kevin wrote: > > > > actually I'm curious whether it's still necessary to __detect__ PCH. Could > > > > we assume a 1:1 mapping between GPU and PCH, e.g. BDW already hard > > > > code the knowledge: > > > > > > > > } else if (IS_BROADWELL(dev)) { > > > > dev_priv->pch_type = PCH_LPT; > > > > dev_priv->pch_id = > > > > > > INTEL_PCH_LPT_LP_DEVICE_ID_TYPE; > > > > DRM_DEBUG_KMS("This is Broadwell, > > assuming " > > > > "LynxPoint LP PCH\n"); > > > > > > > > Or if there is real usage on non-fixed mapping (not majority), could it be a > > > > better option to have fixed mapping as a fallback instead of leaving as > > > > PCH_NONE? Then even when Qemu doesn't provide a special tweaked > > PCH, > > > > the majority case just works. > > > > > > I guess we can do it, at least I haven't seen any strange combinations in > > > the wild outside of Intel ... > > > > How big is the QA matrix for this? Would it make sense to just > > include the latest hardware (say going two generations back) > > and ignore the older one? > > suppose minimal or no QA effort on bare metal, if we only conservatively > change the fallback path which is today not supposed to function with > PCH_NONE. so it's only same amount of QA effort as whatever else is > proposed in this passthru upstreaming task. I agree no need to cover > older model, possibly just snb, ivb and hsw, but will leave Tiejun to answer > the overall goal. Yeah, I'd be ok with the approach of using defaults if we can't recognize the pch - if anyone screams we can either quirk or figure something else out. -Daniel -- Daniel Vetter Software Engineer, Intel Corporation +41 (0) 79 365 57 48 - http://blog.ffwll.ch -- 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/