Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753442Ab3FZWz2 (ORCPT ); Wed, 26 Jun 2013 18:55:28 -0400 Received: from mail-oa0-f49.google.com ([209.85.219.49]:39288 "EHLO mail-oa0-f49.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753270Ab3FZWz0 (ORCPT ); Wed, 26 Jun 2013 18:55:26 -0400 MIME-Version: 1.0 In-Reply-To: References: <1372177330-28013-1-git-send-email-mika.westerberg@linux.intel.com> <1372177330-28013-7-git-send-email-mika.westerberg@linux.intel.com> From: Bjorn Helgaas Date: Wed, 26 Jun 2013 16:55:05 -0600 Message-ID: Subject: Re: [PATCH 6/6] x86/PCI: quirk Thunderbolt PCI-to-PCI bridges To: Yinghai Lu Cc: Mika Westerberg , Greg Kroah-Hartman , "Rafael J. Wysocki" , Jesse Barnes , "Ronciak, John" , "Penner, Miles J" , Bruce Allan , "Kirill A. Shutemov" , Heikki Krogerus , "linux-kernel@vger.kernel.org" , "linux-pci@vger.kernel.org" , "x86@kernel.org" 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: 1473 Lines: 27 On Wed, Jun 26, 2013 at 4:31 PM, Yinghai Lu wrote: > On Wed, Jun 26, 2013 at 3:26 PM, Yinghai Lu wrote: >> On Wed, Jun 26, 2013 at 3:18 PM, Bjorn Helgaas wrote: >>> On Tue, Jun 25, 2013 at 10:22 AM, Mika Westerberg >>> wrote: >>>> Thunderbolt PCI-to-PCI bridges typically use BIOS "assisted" enumeration. >>>> This means that the BIOS will allocate bridge resources based on some >>>> assumptions of a maximum Thunderbolt chain. It also disables native PCIe >>>> hotplug of the root port where the Thunderbolt host router is connected. > ... > During acpi hotplug, firmare could do extra help for us like assign > some resources to pci device bars, so it is NOT "boot-time". Really? How can firmware assign BARs at hotplug-time? I mean, obviously firmware *can* write things to the BARs before giving the device to the OS, but how would it know what to write? I assume the OS owns the address space, and it can change the upstream bridge windows or the BARs of another device on the bus at any time, subject to the OS's own issues as far as quiescing or unbinding drivers, etc., but without coordinating with the BIOS. 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/