From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757206Ab3G3Dug (ORCPT ); Mon, 29 Jul 2013 23:50:36 -0400 Received: from szxga02-in.huawei.com ([119.145.14.65]:13572 "EHLO szxga02-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757100Ab3G3Due (ORCPT ); Mon, 29 Jul 2013 23:50:34 -0400 Message-ID: <51F73730.9070402@huawei.com> Date: Tue, 30 Jul 2013 11:46:56 +0800 From: Yijing Wang User-Agent: Mozilla/5.0 (Windows NT 6.1; rv:17.0) Gecko/20130620 Thunderbird/17.0.7 MIME-Version: 1.0 To: Bjorn Helgaas CC: "linux-kernel@vger.kernel.org" , Don Dutile , Paul Bolle , "linux-pci@vger.kernel.org" , Rafael , Hanjun Guo , Jiang Liu , Oliver Neukum , Gu Zheng Subject: Re: [PATCH -v3 3/3] PCI,pciehp: use PCIe DSN to identify device change during suspend References: <1373621543-54836-1-git-send-email-wangyijing@huawei.com> <1373621543-54836-4-git-send-email-wangyijing@huawei.com> In-Reply-To: Content-Type: text/plain; charset="ISO-8859-1" Content-Transfer-Encoding: 7bit X-Originating-IP: [10.135.76.69] X-CFilter-Loop: Reflected Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > I'm not sure this is implemented at the correct place. The idea of > using the serial number to detect card swaps is not really specific to > pciehp. I know the Device Serial Number capability is defined in the > PCIe spec, but it doesn't *require* any PCIe functionality, and > there's no reason a similar capability couldn't be defined for > conventional PCI. > > I don't know much about it, but conventional PCI *does* in fact > support the VPD capability, which can contain a serial number. I > wonder if we should enhance pci_device_serial_number() to look for a > VPD serial number if there's no PCIe DSN. Then we would want this > check for card swap in a more generic place, e.g., somewhere in > pci_scan_slot(), so all forms of hotplug would benefit from it. Hi Bjorn, I'm reworking this patch, but found some strange info about vpd serial number. I have two x86 machines, they almost have the same hardware topology. But by lspci, I found two different Broadcom BCM5709 NIC in different machine have the same vpd serial number. If this is normal, vpd serial number seems to be useless for identify device change. The first machine: linux:/home/yijing # lspci -vvv -s 0000:01:00.0 01:00.0 Ethernet controller: Broadcom Corporation NetXtreme II BCM5709 Gigabit Ethernet (rev 20) Subsystem: Broadcom Corporation NetXtreme II BCM5709 Gigabit Ethernet Control: I/O- Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop- ParErr- Stepping- SERR- FastB2B- DisINTx- Status: Cap+ 66MHz- UDF- FastB2B- ParErr- DEVSEL=fast >TAbort- SERR- TAbort- SERR- > Also, I think it's possible to use acpiphp for ExpressCard slots, and > this patch doesn't help acpiphp detect card swaps. I don't see any > mention of suspend/resume in acpiphp, so I don't know if it does > anything at all to detect card changes while suspended. Maybe Rafael > can shed some light? > > I put the first two patches on a pci/yijing-dsn-v3 branch while we > work out the details of this one. > > Bjorn > >> } else if (!list_empty(&pbus->devices)) { >> pciehp_disable_slot(slot); >> } >> -- >> 1.7.1 >> >> > > . > -- Thanks! Yijing