From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mga11.intel.com ([192.55.52.93]:56468 "EHLO mga11.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1030457AbdIZOR1 (ORCPT ); Tue, 26 Sep 2017 10:17:27 -0400 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 6/7] PCI: pciehp: Do not clear Presence Detect Changed during initialization Date: Tue, 26 Sep 2017 17:17:19 +0300 Message-Id: <20170926141720.25067-7-mika.westerberg@linux.intel.com> In-Reply-To: <20170926141720.25067-1-mika.westerberg@linux.intel.com> References: <20170926141720.25067-1-mika.westerberg@linux.intel.com> Sender: linux-pci-owner@vger.kernel.org List-ID: 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, -- 2.14.1