From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Message-ID: <50F2D3A3.6080602@gmail.com> Date: Sun, 13 Jan 2013 23:32:51 +0800 From: Jiang Liu MIME-Version: 1.0 To: "Rafael J. Wysocki" CC: Yinghai Lu , Bjorn Helgaas , Len Brown , Taku Izumi , Jiang Liu , linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org, linux-acpi@vger.kernel.org Subject: Re: [PATCH v8 11/22] PCI: correctly detect ACPI PCI host bridge objects References: <1357944049-29620-1-git-send-email-yinghai@kernel.org> <1357944049-29620-12-git-send-email-yinghai@kernel.org> <2669837.JomPNBOLKK@vostro.rjw.lan> In-Reply-To: <2669837.JomPNBOLKK@vostro.rjw.lan> Content-Type: text/plain; charset=UTF-8 Sender: linux-acpi-owner@vger.kernel.org List-ID: On 01/13/2013 07:34 AM, Rafael J. Wysocki wrote: > On Friday, January 11, 2013 02:40:38 PM Yinghai Lu wrote: >> From: Jiang Liu >> >> The code in pci_root_hp.c depends on function acpi_is_root_bridge() >> to check whether an ACPI object is a PCI host bridge or not. >> If an ACPI device hasn't been created for the ACPI object yet, >> function acpi_is_root_bridge() will return false even if the object >> is a PCI host bridge object. That behavior will cause two issues: >> 1) No ACPI notification handler installed for PCI host bridges absent >> at startup, so hotplug events for those bridges won't be handled. >> 2) rescan_root_bridge() can't reenumerate offlined PCI host bridges >> because the ACPI devices have been already destroyed. >> >> So use acpi_match_object_info_ids() to correctly detect PCI host bridges. >> >> -v2: update to use acpi_match_object_info_ids() from Tang Chen - Yinghai >> -v3: drop the PNP0A008, according to Bjorn. >> >> Signed-off-by: Jiang Liu >> Signed-off-by: Yinghai Lu >> Cc: Len Brown >> Cc: linux-acpi@vger.kernel.org >> --- >> drivers/acpi/pci_root.c | 19 ++++++++++++++++++- >> 1 file changed, 18 insertions(+), 1 deletion(-) >> >> diff --git a/drivers/acpi/pci_root.c b/drivers/acpi/pci_root.c >> index 5ae36d8..d30fb94 100644 >> --- a/drivers/acpi/pci_root.c >> +++ b/drivers/acpi/pci_root.c >> @@ -923,6 +923,23 @@ static void handle_hotplug_event_root(acpi_handle handle, u32 type, >> _handle_hotplug_event_root); >> } >> >> +static bool acpi_is_root_bridge_object(acpi_handle handle) >> +{ >> + struct acpi_device_info *info = NULL; >> + acpi_status status; >> + bool ret; >> + >> + status = acpi_get_object_info(handle, &info); >> + if (ACPI_FAILURE(status)) >> + return false; >> + >> + ret = !acpi_match_object_info_ids(info, root_device_ids); >> + > > Well, I kind of don't understand why don't we check info->flags > against ACPI_PCI_ROOT_BRIDGE that acpi_get_object_info() sets for us if it > finds a PCI root bridge? Hi Rafael, Thanks for reminder, we should test ACPI_PCI_ROOT_BRIDGE flag instead of a redundant calling to acpi_match_object_info_ids(). To be honest, I don't know the existence of ACPI_PCI_ROOT_BRIDGE flag before:( > >> + kfree(info); >> + >> + return ret; >> +} >> + >> static acpi_status __init >> find_root_bridges(acpi_handle handle, u32 lvl, void *context, void **rv) >> { >> @@ -931,7 +948,7 @@ find_root_bridges(acpi_handle handle, u32 lvl, void *context, void **rv) >> .pointer = objname }; >> int *count = (int *)context; >> >> - if (!acpi_is_root_bridge(handle)) >> + if (!acpi_is_root_bridge_object(handle)) >> return AE_OK; >> >> (*count)++; >> > > Thanks, > Rafael > >