From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1422725Ab2JLKiB (ORCPT ); Fri, 12 Oct 2012 06:38:01 -0400 Received: from szxga02-in.huawei.com ([119.145.14.65]:58392 "EHLO szxga02-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1422685Ab2JLKh7 (ORCPT ); Fri, 12 Oct 2012 06:37:59 -0400 Message-ID: <5077F2C2.1010300@huawei.com> Date: Fri, 12 Oct 2012 18:36:50 +0800 From: Jiang Liu User-Agent: Mozilla/5.0 (Windows NT 5.1; rv:9.0) Gecko/20111222 Thunderbird/9.0.1 MIME-Version: 1.0 To: Tang Chen CC: , , , , , , Subject: Re: [PATCH 2/3] Do not use acpi_device to find pci root bridge in _init code. References: <1350037890-5899-1-git-send-email-tangchen@cn.fujitsu.com> <1350037890-5899-3-git-send-email-tangchen@cn.fujitsu.com> In-Reply-To: <1350037890-5899-3-git-send-email-tangchen@cn.fujitsu.com> Content-Type: text/plain; charset="ISO-8859-1" Content-Transfer-Encoding: 7bit X-Originating-IP: [10.108.108.229] X-CFilter-Loop: Reflected Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2012-10-12 18:31, Tang Chen wrote: > When the kernel is being initialized, and some hardwares are not added > to system, there won't be acpi_device structs for these devices. But > acpi_is_root_bridge() depends on acpi_device struct. As a result, all > the not-added root bridge will not be judged as a root bridge in > find_root_bridges(). And further more, no handle_hotplug_event_root() > notifier will be installed for them. > > This patch introduces a new api to find all root bridges in system by > getting HID directly from ACPI namespace, not depending on acpi_device > struct. > > Signed-off-by: Tang Chen > --- > drivers/acpi/pci_root.c | 27 ++++++++++++++++++++++----- > 1 files changed, 22 insertions(+), 5 deletions(-) > > diff --git a/drivers/acpi/pci_root.c b/drivers/acpi/pci_root.c > index 7d0fb03..3819bee 100644 > --- a/drivers/acpi/pci_root.c > +++ b/drivers/acpi/pci_root.c > @@ -128,9 +128,6 @@ EXPORT_SYMBOL_GPL(acpi_get_pci_rootbridge_handle); > /** > * acpi_is_root_bridge - determine whether an ACPI CA node is a PCI root bridge > * @handle - the ACPI CA node in question. > - * > - * Note: we could make this API take a struct acpi_device * instead, but > - * for now, it's more convenient to operate on an acpi_handle. > */ > int acpi_is_root_bridge(acpi_handle handle) > { > @@ -138,8 +135,28 @@ int acpi_is_root_bridge(acpi_handle handle) > struct acpi_device *device; > > ret = acpi_bus_get_device(handle, &device); > - if (ret) > - return 0; > + if (ret) { > + /** > + * If a device is not added to the system yet, there won't be > + * an acpi_device struct for it. But it doesn't mean it is not > + * a PCI root bridge. In this case we need to get HID and CID > + * from ACPI namespace directly. > + */ > + struct acpi_device_info *info; > + acpi_status status; > + status = acpi_get_object_info(handle, &info); > + if (ACPI_FAILURE(status)) { > + printk(KERN_ERR PREFIX "%s: Error reading" > + "device info\n", __func__); > + return 0; > + } > + > + ret = acpi_match_object_info_ids(info, root_device_ids); > + if (ret) > + return 0; > + else > + return 1; > + } I have sent a similar patch to Yinghai before. For simplicity, we could use acpi_match_object_info_ids() instead of acpi_match_device_ids() directly. Thanks! Gerry > > ret = acpi_match_device_ids(device, root_device_ids); > if (ret)