Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756974Ab3EJRJe (ORCPT ); Fri, 10 May 2013 13:09:34 -0400 Received: from mail-oa0-f45.google.com ([209.85.219.45]:55338 "EHLO mail-oa0-f45.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754348Ab3EJRJd (ORCPT ); Fri, 10 May 2013 13:09:33 -0400 MIME-Version: 1.0 In-Reply-To: <517E9DAC.7030709@gmail.com> References: <1366940798-15268-1-git-send-email-yinghai@kernel.org> <517E9DAC.7030709@gmail.com> From: Bjorn Helgaas Date: Fri, 10 May 2013 11:09:10 -0600 Message-ID: Subject: Re: [PATCH -v3] PCI, ACPI, hotplug: Fix BUS_CHECK event handle on root bridge To: Jiang Liu Cc: Yinghai Lu , "Rafael J. Wysocki" , Jiang Liu , Gavin Guo , "linux-pci@vger.kernel.org" , "linux-acpi@vger.kernel.org" , "linux-kernel@vger.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: 3227 Lines: 73 On Mon, Apr 29, 2013 at 10:19 AM, Jiang Liu wrote: > Hi Yinghai, > Reviewed-by: Jiang Liu > Thanks! > > On 04/26/2013 09:46 AM, Yinghai Lu wrote: >> Gavin found that acpiphp does not handle hotplug anymore even after >> now we have acpiphp built-in preparing for v3.10. >> >> Bjorn analyzed bootlog, he found that >> acpiphp: ACPI Hot Plug PCI Controller Driver version: 0.5 >> ACPI: PCI Root Bridge [PCI0] (domain 0000 [bus 00-3e]) >> \_SB_.PCI0:_OSC invalid UUID >> acpiphp: Slot [1] registered >> acpiphp: Slot [1-1] registered >> acpi root: \_SB_.PCI0 notify handler is installed >> _handle_hotplug_event_root: Bus check notify on \_SB_.PCI0 >> _handle_hotplug_event_root: Bus check notify on \_SB_.PCI0 >> And that means: >> So we should be using acpiphp, which you do have built in statically, >> and it found a couple slots. And we did get two bus check notifies on >> \_SB_.PCI0, so we *should* be re-enumerating PCI bus 0000:00. But it >> looks like we're handling this as a host bridge hotplug event instead >> of a PCI device hotplug. My guess is that >> handle_root_bridge_insertion() does nothing because the PCI0 ACPI >> device already exists, though I would expect to see the "acpi device >> exists..." in your dmesg log if this were the case. >> >> Also according to Rafael and Bjorn, it is perfect fine that we >> should enumerate bus by sending event to root bridge after hotadd >> device to slots under that root bridge or children bridges. >> >> It turns out that it is regression caused by >> | commit 668192b678201d2fff27c6cc76bb003c1ec4a52a >> | Author: Yinghai Lu >> | Date: Mon Jan 21 13:20:48 2013 -0800 >> | >> | PCI: acpiphp: Move host bridge hotplug to pci_root.c >> >> We should check slots when BUS_CHECK is sent to root bridge acpi handle. >> >> Restore the old behavoir by calling acpi_check_bridge and check_sub_bridge >> in acpiphp. >> >> Jiang Liu acctually have simimar patch but it forgets calling >> acpi_check_bridge() for system that have slots on root bus directly. >> That is still valid, as in QEMU we still have that slots on bus 0 at >> least. But my first version patch wrongly check if root bridge exists >> before check_sub_bridge for children bridges. >> >> -v2: Don't check bridge for acpi_walk_namespace with check_sub_bridges. >> also put back bridge reference. >> -v3: More changelog and etc. >> >> Reported-by: Gavin Guo >> Tested-by: Gavin Guo >> Signed-off-by: Yinghai Lu I added the Acked-by and Reviewed-by and opened https://bugzilla.kernel.org/show_bug.cgi?id=57961 just as a place to store the dmesg logs. I also backported it to v3.9 and added a CC: stable tag because I think v3.9 has the same issue. The backport is also attached to the bugzilla. I'll ask Linus to put this in v3.10. Thanks, 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/