Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757351Ab3J1Rcz (ORCPT ); Mon, 28 Oct 2013 13:32:55 -0400 Received: from mail-ie0-f182.google.com ([209.85.223.182]:64859 "EHLO mail-ie0-f182.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757333Ab3J1Rcx (ORCPT ); Mon, 28 Oct 2013 13:32:53 -0400 MIME-Version: 1.0 In-Reply-To: <526BF37E.8040801@intel.com> References: <1381493941-4650-1-git-send-email-tianyu.lan@intel.com> <1381493941-4650-6-git-send-email-tianyu.lan@intel.com> <20131016235541.GD17866@google.com> <525F7F0F.5010306@intel.com> <52612D1C.4070701@intel.com> <20131023223904.GA18454@google.com> <526BF37E.8040801@intel.com> From: Bjorn Helgaas Date: Mon, 28 Oct 2013 11:32:30 -0600 Message-ID: Subject: Re: [Resend PATCH 5/5] IA64/PCI/ACPI: Rework PCI root bridge ACPI resource conversion To: Lan Tianyu Cc: Tony Luck , Len Brown , "Rafael J. Wysocki" , Yinghai Lu , "linux-ia64@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "linux-acpi@vger.kernel.org" , "Yoknis, Mike" , "Pearson, Greg" Content-Type: text/plain; charset=ISO-8859-1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2015 Lines: 45 On Sat, Oct 26, 2013 at 10:53 AM, Lan Tianyu wrote: > On 10/24/2013 06:39 AM, Bjorn Helgaas wrote: >> On Fri, Oct 18, 2013 at 08:44:12PM +0800, Lan Tianyu wrote: >>> >>> On 10/18/2013 04:33 AM, Bjorn Helgaas wrote: >>>> I wonder if it would make sense to make >>>> acpi_dev_resource_address_space() ignore addr.translation_offset for >>>> IO resources. Or maybe ignore it if the _TTP (type translation) bit >>>> is set? >>> >>> >>> I wonder why current code doesn't check _TTP? The code in the >>> add_io_space() seems to think _TTP is always set, right? >> >> I think it's an oversight, and you should fix it. I suggest that you >> ignore the _TRA value when _TTP is set. Obviously this only applies >> to I/O port resources, since _TTP is only defined in the I/O Resource >> Flag (Table 6-185 in ACPI 5.0 spec). > > _TTP is also defined in the Memory Resource flag, Please have a look at > Table 6-184 in the ACPI 5.0 Spec. Yes, you're right. That would be for a host bridge that converts I/O on the primary (upstream) side of the bridge to memory on the PCI side. I've never seen such a bridge, and I can't really imagine why anybody would do that. But I guess you should be able to safely ignore _TRA when _TTP is set in either a MEM or IO descriptor, because the same reasoning should apply to both. > I am not sure how to deal with _TTP unsetting io resource? _TTP unsetting > mean the resource is IO on the primary side and also IO on the secondary > side. If _TTP is not set, I guess you would apply _TRA. That's what you already do for MEM descriptors, and think you should just do the same for IO descriptors. I would guess that having _TTP = 0 and _TRA != 0 is rare for IO descriptors, but I suppose it could happen. 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/