Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751977Ab3EBGrx (ORCPT ); Thu, 2 May 2013 02:47:53 -0400 Received: from mga03.intel.com ([143.182.124.21]:63207 "EHLO mga03.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750771Ab3EBGrv (ORCPT ); Thu, 2 May 2013 02:47:51 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.87,594,1363158000"; d="scan'208";a="296359092" Date: Wed, 1 May 2013 23:53:58 -0700 From: Bin Gao To: Bjorn Helgaas Cc: Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" , "x86@kernel.org" , Jacob Pan , Jesse Barnes , Greg Kroah-Hartman , "linux-kernel@vger.kernel.org" Subject: Re: x86/pci/mrst: force all pci config toward 0:0:0, 0:2:0 and 0:3:0 to type 1 Message-ID: <20130502065358.GA41008@bingao-desk1.fm.intel.com> References: <20130430072147.GA37866@bingao-desk1.fm.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: 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 Content-Length: 1245 Lines: 29 On Wed, May 01, 2013 at 11:17:10AM -0600, Bjorn Helgaas wrote: > Is there any possibility of multi-function devices at bus 0, device 0, 2, or 3? > > What about bridges -- can any of these be a bridge? > > If either of those could happen, these checks could be too specific. 0:2:0 and 0:3:0 are the only 2 devices behind the bridge 0:0:0. These devices don't implement pcie capability list in legacy config space so no offset above 255 would be triggered. The fixed bar pcie capability located at 0x100 is for pci-shimed device only, not for 0, 2 and 3. But current implementation applies it to 0, 2 and 3 as well. This is what the patch is going to address. > > Is there a doc that identifies these cases where config mechanism #1 > should be used instead of MMCONFIG? Unfortunately no doc identifies this. But since FW doesn't provide pci shim for device 0, 2 and 3, and these 3 real pci devices have only 256 bytes legacy pci config space so they can only be accessed by type 1. > > Bjorn > -- 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/