Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752975AbYCLMhY (ORCPT ); Wed, 12 Mar 2008 08:37:24 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751351AbYCLMhL (ORCPT ); Wed, 12 Mar 2008 08:37:11 -0400 Received: from fgwmail7.fujitsu.co.jp ([192.51.44.37]:39603 "EHLO fgwmail7.fujitsu.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750982AbYCLMhJ (ORCPT ); Wed, 12 Mar 2008 08:37:09 -0400 Message-ID: <47D7CBAF.4090308@jp.fujitsu.com> Date: Wed, 12 Mar 2008 21:25:19 +0900 From: Kenji Kaneshige User-Agent: Thunderbird 2.0.0.12 (Windows/20080213) MIME-Version: 1.0 To: kristen.c.accardi@intel.com CC: Alex Chiang , Gary Hade , Matthew Wilcox , gregkh@suse.de, lenb@kernel.org, rick.jones2@hp.com, linux-kernel@vger.kernel.org, linux-pci@atrey.karlin.mff.cuni.cz, pcihpd-discuss@lists.sourceforge.net, linux-acpi@vger.kernel.org Subject: Re: [PATCH 0/4, v3] Physical PCI slot objects References: <20071117182954.GA25003@ldl.fc.hp.com> <20071119233225.GA6931@us.ibm.com> <20071126222253.GA31708@ldl.fc.hp.com> <474E6E82.40307@jp.fujitsu.com> <20080311121516.42e3a727@appleyard> In-Reply-To: <20080311121516.42e3a727@appleyard> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 6639 Lines: 158 Hi Kristen, > Hello - back to this mail for a moment. I wanted to talk about acpiphp > again. You say that acpiphp has this same problem as Alex's driver wrt > evalating _SUN on a non existant object. If we skip registering the > slot in acpiphp's register_slot function if it returns 0 for _STA, we > will not detect any hotplug slots, since leaf nodes will return 0 for > _STA if a device is not present. Should we only skip it if it's parent > is a p2p bridge that has _EJ0 and the parent's _STA says empty? I've been not looking at acpiphp code for a long time. So I need refresh my memory before answering. Sorry. But I want to say one thing. We can detect all the hotplug slots if ACPI firmware doesn't provide _STA. We don't need _STA for PCI hotplug slots and should not provide _STA for PCI hotplug slots if the system is based on ACPI2.0 or later, because those are _ADR based devices (PCI root bridge, which is _HID based device, is a exception). For _ADR based devices, we should check the presence of the device using PCI bus drivers instead of evaluating _STA. Please see the section of "_EJx (Eject)" in ACPI2.0b or later spec. It says "For _HID devices, OSPM evaluates the _STA method. For _ADR devices, OSPM checks with the bus driver for that device.". BTW, acpiphp_glue.c says _STA is "optionally". I don't know what it means. Thanks, Kenji Kaneshige Kristen Carlson Accardi wrote: > On Thu, 29 Nov 2007 16:47:14 +0900 > Kenji Kaneshige wrote: > >>> Hi Gary, Kenji-san, et. al, >>> >>> * Gary Hade : >>>> Alex, What I was trying to suggest is a boot-time kernel >>>> option, not a kernel configuration option. The basic idea is >>>> to give the user (with a single binary kernel) the ability to >>>> include your ACPI-PCI slot driver feature changes only when >>>> they are really needed. In addition to reducing the number of >>>> system/PCI hotplug driver combinations where your changes would >>>> need to be validated, I believe would also help alleviate other >>>> worries (e.g. Andi Kleen's memory consumption concern). I >>>> believe this goal could also be achieved with the kernel config >>>> option by making the pci_slot module runtime loadable with the >>>> PCI hotplug drivers only visiting your new code when the >>>> pci_slot driver is loaded, although I think this would be more >>>> difficult to implement. >>> I have modified my patch series so that the final patch that >>> introduces my ACPI-PCI slot driver is a full-fledged module, that >>> has a tristate Kconfig option. >>> >> Thank you for your good job. >> >> I tested shpchp and pciehp both with and without pci_slot module. >> There seems no regression from shpchp and pciehp's point of view. >> (I had a little concern about the hotplug slots' name that vary >> depending on whether pci_slot functionality is enabled or disabled. >> But, now that we can build pci_slot driver as a kernel module, I >> don't think it is a big problem). >> >> Only the problems is that I got Call Traces with the following error >> messages when pci_slot driver was loaded, and one strange slot named >> '1023' was registered (other slots are fine). This is the same problem >> I reported before. >> >> sysfs: duplicate filename '1023' can not be created >> WARNING: at fs/sysfs/dir.c:424 sysfs_add_one() >> >> kobject_add failed for 1023 with -EEXIST, don't try to register >> things with the same name in the same directory. >> >> On my system, hotplug slots themselves can be added, removed and >> replaced with the ohter type of I/O box. The ACPI firmware tells OS >> the presence of those slots using _STA method (That is, it doesn't >> use 'LoadTable()' AML operator). On the other hand, current pci_slot >> driver doesn't check _STA. As a result, pci_slot driver tryied to >> register the invalid (non-existing) slots. The ACPI firmware of my >> system returns '1023' if the invalid slot's _SUN is evaluated. This >> is the cause of Call Traces mentioned above. To fix this problem, >> pci_slot driver need to check _STA when scanning ACPI Namespace. >> >> I'm sorry for reporting this so late. I'm attaching the patch to fix >> the problem. This is against 2.6.24-rc3 with your patches applied. >> Could you try it? >> >> BTW, acpiphp also seems to have the same problem... >> >> Thanks, >> Kenji Kaneshige > > Hello - back to this mail for a moment. I wanted to talk about acpiphp > again. You say that acpiphp has this same problem as Alex's driver wrt > evalating _SUN on a non existant object. If we skip registering the > slot in acpiphp's register_slot function if it returns 0 for _STA, we > will not detect any hotplug slots, since leaf nodes will return 0 for > _STA if a device is not present. Should we only skip it if it's parent > is a p2p bridge that has _EJ0 and the parent's _STA says empty? > > Your input is appreciated, > Kristen > >> --- >> drivers/acpi/pci_slot.c | 13 +++++++++++++ >> 1 file changed, 13 insertions(+) >> >> Index: linux-2.6.24-rc3/drivers/acpi/pci_slot.c >> =================================================================== >> --- linux-2.6.24-rc3.orig/drivers/acpi/pci_slot.c >> +++ linux-2.6.24-rc3/drivers/acpi/pci_slot.c >> @@ -113,10 +113,17 @@ register_slot(acpi_handle handle, u32 lv >> int device; >> unsigned long sun; >> char name[KOBJ_NAME_LEN]; >> + acpi_status status; >> + struct acpi_device *dummy_device; >> >> struct pci_slot *pci_slot; >> struct pci_bus *pci_bus = context; >> >> + /* Skip non-existing device object. */ >> + status = acpi_bus_get_device(handle, &dummy_device); >> + if (ACPI_FAILURE(status)) >> + return AE_OK; >> + >> if (check_slot(handle, &device, &sun)) >> return AE_OK; >> >> @@ -150,12 +157,18 @@ walk_p2p_bridge(acpi_handle handle, u32 >> acpi_status status; >> acpi_handle dummy_handle; >> acpi_walk_callback user_function; >> + struct acpi_device *dummy_device; >> >> struct pci_dev *dev; >> struct pci_bus *pci_bus; >> struct p2p_bridge_context child_context; >> struct p2p_bridge_context *parent_context = context; >> >> + /* Skip non-existing device object. */ >> + status = acpi_bus_get_device(handle, &dummy_device); >> + if (ACPI_FAILURE(status)) >> + return AE_OK; >> + >> pci_bus = parent_context->pci_bus; >> user_function = parent_context->user_function; >> >> > > -- 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/