From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx1.redhat.com ([209.132.183.28]:39440 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753070AbaKGWyq (ORCPT ); Fri, 7 Nov 2014 17:54:46 -0500 From: Alex Williamson Subject: [PATCH] PCI: pciehp: Flush slot control prior to reset To: linux-pci@vger.kernel.org, bhelgaas@google.com Cc: linux-kernel@vger.kernel.org, rajatxjain@gmail.com, yinghai@kernel.org Date: Fri, 07 Nov 2014 15:54:41 -0700 Message-ID: <20141107225359.1937.61243.stgit@gimli.home> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Sender: linux-pci-owner@vger.kernel.org List-ID: Since 3461a068661c we don't automatically do a pcie_wait_cmd() for as part of pcie_write_cmd(), it needs to be called explicitly or triggered by the next pcie_write_cmd(). However, when we do a secondary bus reset and we're using pcie_write_cmd() to make sure that we don't see that bus reset as a hotplug event, we really want to make sure the update is complete. Testing on an old Lenovo S20 system, which sets surprise hotplug for some slots, this failure to flush results in a link down event seen by the hotplug controller when we issue the bus reset and returns us to the undesireable behavior of removing and re-adding the device. Force a flush by adding an explicit call to pcie_wait_cmd(). Signed-off-by: Alex Williamson Cc: stable@vger.kernel.org [3.17] --- drivers/pci/hotplug/pciehp_hpc.c | 1 + 1 file changed, 1 insertion(+) diff --git a/drivers/pci/hotplug/pciehp_hpc.c b/drivers/pci/hotplug/pciehp_hpc.c index 0ebf754..e540966 100644 --- a/drivers/pci/hotplug/pciehp_hpc.c +++ b/drivers/pci/hotplug/pciehp_hpc.c @@ -660,6 +660,7 @@ int pciehp_reset_slot(struct slot *slot, int probe) pci_pcie_cap(ctrl->pcie->port) + PCI_EXP_SLTCTL, 0); if (pciehp_poll_mode) del_timer_sync(&ctrl->poll_timer); + pcie_wait_cmd(ctrl); pci_reset_bridge_secondary_bus(ctrl->pcie->port);