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authorAshok Raj <ashok.raj@intel.com>2016-11-19 11:32:45 +0300
committerBjorn Helgaas <bhelgaas@google.com>2016-12-08 02:00:44 +0300
commit385895fef6b5f4723e33d0e58251c45bc708132d (patch)
tree615e9d8a71998de31f3c9c742cfed26ef6822439 /drivers/pci
parentb11d207fb229943d75c17cef4ae3fa980f0cee79 (diff)
downloadlinux-385895fef6b5f4723e33d0e58251c45bc708132d.tar.xz
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 <ashok.raj@intel.com> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> Reviewed-by: Keith Busch <keith.busch@intel.com>
Diffstat (limited to 'drivers/pci')
-rw-r--r--drivers/pci/hotplug/pciehp_hpc.c21
1 files changed, 12 insertions, 9 deletions
diff --git a/drivers/pci/hotplug/pciehp_hpc.c b/drivers/pci/hotplug/pciehp_hpc.c
index b57fc6d6e28a..026830a138ae 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;
}