From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753274AbdJMSgZ (ORCPT ); Fri, 13 Oct 2017 14:36:25 -0400 Received: from mga05.intel.com ([192.55.52.43]:33426 "EHLO mga05.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752935AbdJMSf5 (ORCPT ); Fri, 13 Oct 2017 14:35:57 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.43,372,1503385200"; d="scan'208";a="1205591941" From: Mika Westerberg To: Bjorn Helgaas Cc: Ashok Raj , Keith Busch , "Rafael J . Wysocki" , Lukas Wunner , Michael Jamet , Yehezkel Bernat , Mario.Limonciello@dell.com, Mika Westerberg , linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH v2 7/8] PCI: pciehp: Do not clear Presence Detect Changed during initialization Date: Fri, 13 Oct 2017 21:35:47 +0300 Message-Id: <20171013183548.68283-8-mika.westerberg@linux.intel.com> X-Mailer: git-send-email 2.14.2 In-Reply-To: <20171013183548.68283-1-mika.westerberg@linux.intel.com> References: <20171013183548.68283-1-mika.westerberg@linux.intel.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org It is possible that the hotplug event has already happened before the driver is attached to a PCIe hotplug downstream port. If we just clear the status we never get the hotplug interrupt and thus the event will be missed. To make sure that does not happen, we leave Presence Detect Changed bit untouched during initialization. Then once the event is unmasked we get an interrupt and handle the hotplug event properly. Signed-off-by: Mika Westerberg --- drivers/pci/hotplug/pciehp_hpc.c | 11 ++++++++--- 1 file changed, 8 insertions(+), 3 deletions(-) diff --git a/drivers/pci/hotplug/pciehp_hpc.c b/drivers/pci/hotplug/pciehp_hpc.c index 83c93f9da65a..bc1622aa7a05 100644 --- a/drivers/pci/hotplug/pciehp_hpc.c +++ b/drivers/pci/hotplug/pciehp_hpc.c @@ -862,11 +862,16 @@ struct controller *pcie_init(struct pcie_device *dev) if (link_cap & PCI_EXP_LNKCAP_DLLLARC) ctrl->link_active_reporting = 1; - /* Clear all remaining event bits in Slot Status register */ + /* + * Clear all remaining event bits in Slot Status register except + * Presence Detect Changed. We want to make sure possible + * hotplug event is triggered when the interrupt is unmasked so + * that we don't lose that event. + */ pcie_capability_write_word(pdev, PCI_EXP_SLTSTA, PCI_EXP_SLTSTA_ABP | PCI_EXP_SLTSTA_PFD | - PCI_EXP_SLTSTA_MRLSC | PCI_EXP_SLTSTA_PDC | - PCI_EXP_SLTSTA_CC | PCI_EXP_SLTSTA_DLLSC); + PCI_EXP_SLTSTA_MRLSC | PCI_EXP_SLTSTA_CC | + PCI_EXP_SLTSTA_DLLSC); ctrl_info(ctrl, "Slot #%d AttnBtn%c PwrCtrl%c MRL%c AttnInd%c PwrInd%c HotPlug%c Surprise%c Interlock%c NoCompl%c LLActRep%c\n", (slot_cap & PCI_EXP_SLTCAP_PSN) >> 19, -- 2.14.2