From 385895fef6b5f4723e33d0e58251c45bc708132d Mon Sep 17 00:00:00 2001 From: Ashok Raj Date: Sat, 19 Nov 2016 00:32:45 -0800 Subject: [PATCH] PCI: pciehp: Prioritize data-link event over presence detect If Slot Status indicates changes in both Data Link Layer Status and Presence Detect, prioritize the Link status change. When both events are observed, pciehp currently relies on the Slot Status Presence Detect State (PDS) to agree with the Link Status Data Link Layer Active status. The Presence Detect State, however, may be set to 1 through out-of-band presence detect even if the link is down, which creates conflicting events. Since the Link Status accurately reflects the reachability of the downstream bus, the Link Status event should take precedence over a Presence Detect event. Skip checking the PDC status if we handled a link event in the same handler. Signed-off-by: Ashok Raj Signed-off-by: Bjorn Helgaas Reviewed-by: Keith Busch --- drivers/pci/hotplug/pciehp_hpc.c | 21 ++++++++++++--------- 1 file changed, 12 insertions(+), 9 deletions(-) diff --git a/drivers/pci/hotplug/pciehp_hpc.c b/drivers/pci/hotplug/pciehp_hpc.c index b57fc6d..026830a 100644 --- a/drivers/pci/hotplug/pciehp_hpc.c +++ b/drivers/pci/hotplug/pciehp_hpc.c @@ -620,8 +620,18 @@ static irqreturn_t pciehp_isr(int irq, void *dev_id) pciehp_queue_interrupt_event(slot, INT_BUTTON_PRESS); } - /* Check Presence Detect Changed */ - if (events & PCI_EXP_SLTSTA_PDC) { + /* + * Check Link Status Changed at higher precedence than Presence + * Detect Changed. The PDS value may be set to "card present" from + * out-of-band detection, which may be in conflict with a Link Down + * and cause the wrong event to queue. + */ + if (events & PCI_EXP_SLTSTA_DLLSC) { + ctrl_info(ctrl, "Slot(%s): Link %s\n", slot_name(slot), + link ? "Up" : "Down"); + pciehp_queue_interrupt_event(slot, link ? INT_LINK_UP : + INT_LINK_DOWN); + } else if (events & PCI_EXP_SLTSTA_PDC) { present = !!(status & PCI_EXP_SLTSTA_PDS); ctrl_info(ctrl, "Slot(%s): Card %spresent\n", slot_name(slot), present ? "" : "not "); @@ -636,13 +646,6 @@ static irqreturn_t pciehp_isr(int irq, void *dev_id) pciehp_queue_interrupt_event(slot, INT_POWER_FAULT); } - if (events & PCI_EXP_SLTSTA_DLLSC) { - ctrl_info(ctrl, "Slot(%s): Link %s\n", slot_name(slot), - link ? "Up" : "Down"); - pciehp_queue_interrupt_event(slot, link ? INT_LINK_UP : - INT_LINK_DOWN); - } - return IRQ_HANDLED; } -- 2.7.4