PCI: pciehp: Clear Presence Detect and Data Link Layer Status Changed on resume

After a suspend/resume cycle the Presence Detect or Data Link Layer Status
Changed bits might be set.  If we don't clear them those events will not
fire anymore and nothing happens for instance when a device is now
hot-unplugged.

Fix this by clearing those bits in a newly introduced function
pcie_reenable_notification().  This should be fine because immediately
after, we check if the adapter is still present by reading directly from
the status register.

Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: stable@vger.kernel.org

1 files changed, 12 insertions, 1 deletions

diff --git a/drivers/pci/hotplug/pciehp_hpc.c b/drivers/pci/hotplug/pciehp_hpc.c
index 74a7f7bde263..022e68f7c3ec 100644
--- a/drivers/pci/hotplug/pciehp_hpc.c
+++ b/drivers/pci/hotplug/pciehp_hpc.c
@@ -667,7 +667,7 @@ static irqreturn_t pcie_isr(int irq, void *dev_id)
 	return handled;
 }
 
-void pcie_enable_notification(struct controller *ctrl)
+static void pcie_enable_notification(struct controller *ctrl)
 {
 	u16 cmd, mask;
 
@@ -705,6 +705,17 @@ void pcie_enable_notification(struct controller *ctrl)
 		 pci_pcie_cap(ctrl->pcie->port) + PCI_EXP_SLTCTL, cmd);
 }
 
+void pcie_reenable_notification(struct controller *ctrl)
+{
+	/*
+	 * Clear both Presence and Data Link Layer Changed to make sure
+	 * those events still fire after we have re-enabled them.
+	 */
+	pcie_capability_write_word(ctrl->pcie->port, PCI_EXP_SLTSTA,
+				   PCI_EXP_SLTSTA_PDC | PCI_EXP_SLTSTA_DLLSC);
+	pcie_enable_notification(ctrl);
+}
+
 static void pcie_disable_notification(struct controller *ctrl)
 {
 	u16 mask;