Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753607Ab3GIH50 (ORCPT ); Tue, 9 Jul 2013 03:57:26 -0400 Received: from szxga03-in.huawei.com ([119.145.14.66]:6980 "EHLO szxga03-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753582Ab3GIH5X (ORCPT ); Tue, 9 Jul 2013 03:57:23 -0400 From: Yijing Wang To: Bjorn Helgaas CC: , , Rafael , Hanjun Guo , , Yijing Wang , Paul Bolle , Oliver Neukum , Gu Zheng Subject: [PATCH 2/2] PCI,pciehp: avoid add a device already exist during pciehp_resume Date: Tue, 9 Jul 2013 15:56:04 +0800 Message-ID: <1373356564-21668-1-git-send-email-wangyijing@huawei.com> X-Mailer: git-send-email 1.7.11.msysgit.1 MIME-Version: 1.0 Content-Type: text/plain 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 Content-Length: 3639 Lines: 117 Currently, pciehp_resume will call pciehp_enable_slot() to add device if there is a device in the slot. But if the device was present before suspend, it's no necessary to add again. Now in such case, there is some uncomfortable message like pciehp 0000:00:1c.1:pcie04: Device 0000:03:00.0 already exists at 0000:03:00, cannot hot-add pciehp 0000:00:1c.1:pcie04: Cannot add device at 0000:03:00 This problem was reported by Paul Bolle The discussion link: http://comments.gmane.org/gmane.linux.kernel.pci/19876 We can use PCIe Device Serial Number to identify the device if device support DSN. currently: 1. slot is empty before suspend, insert card during suspend. In this case, is safe, pciehp will add device by check adapter status register in pciehp_resume. 2. slot is non empty before suspend, remove card during suspend. Also be safe, pciehp will remove device by check adapter status register in pciehp_resume. 3. slot is non empty before suspend, remove card during suspend and insert a new card. Now pciehp just call pciehp_enable_slot() roughly. We should remove the old card firstly, then add the new card. 4. slot is non empty before suspend, no action during suspend. We should do nothing in pciehp_resume, but we call pciehp_enable_slot(), so some uncomfortable messages show like above. In this case, we can improve it a little by add a guard if (!list_empty(bus->devices)). Reported-by: Paul Bolle Signed-off-by: Yijing Wang Cc: Paul Bolle Cc: "Rafael J. Wysocki" Cc: Oliver Neukum Cc: Gu Zheng Cc: linux-pci@vger.kernel.org --- drivers/pci/hotplug/pciehp_core.c | 38 +++++++++++++++++++++++++++++++++--- 1 files changed, 34 insertions(+), 4 deletions(-) diff --git a/drivers/pci/hotplug/pciehp_core.c b/drivers/pci/hotplug/pciehp_core.c index 7d72c5e..d01e093 100644 --- a/drivers/pci/hotplug/pciehp_core.c +++ b/drivers/pci/hotplug/pciehp_core.c @@ -291,6 +291,28 @@ static void pciehp_remove(struct pcie_device *dev) } #ifdef CONFIG_PM + +/* If device support Device Serial Numner, use DSN + * to identify the device + */ +static bool device_in_slot_is_changed(struct pci_bus *pbus) +{ + u64 old_dsn, new_dsn; + struct pci_dev *pdev; + + pdev = pci_get_slot(pbus, PCI_DEVFN(0, 0)); + old_dsn = pdev->sn; + + /* get func 0 device serial number */ + pci_get_dsn(pdev, &new_dsn); + pci_dev_put(pdev); + + if (old_dsn != new_dsn) + return true; + + return false; +} + static int pciehp_suspend (struct pcie_device *dev) { return 0; @@ -300,6 +322,7 @@ static int pciehp_resume (struct pcie_device *dev) { struct controller *ctrl; struct slot *slot; + struct pci_bus *pbus = dev->port->subordinate; u8 status; ctrl = get_service_data(dev); @@ -311,10 +334,17 @@ static int pciehp_resume (struct pcie_device *dev) /* Check if slot is occupied */ pciehp_get_adapter_status(slot, &status); - if (status) - pciehp_enable_slot(slot); - else - pciehp_disable_slot(slot); + if (status) { + if (list_empty(&pbus->devices)) + pciehp_enable_slot(slot); + else if (device_in_slot_is_changed(pbus)) { + pciehp_disable_slot(slot); + pciehp_enable_slot(slot); + } + } else { + if (!list_empty(&pbus->devices)) + pciehp_disable_slot(slot); + } return 0; } #endif /* PM */ -- 1.7.1 -- 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/