Merge branch 'irq-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

torvalds · torvalds · commit 25db69188e03 · 2016-08-12T12:41:51.000-07:00
Pull irq fix from Ingo Molnar:
 "A fix for an MSI regression"

* 'irq-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  genirq/msi: Make sure PCI MSIs are activated early
diff --git a/drivers/pci/msi.c b/drivers/pci/msi.c
@@ -1411,6 +1411,8 @@ struct irq_domain *pci_msi_create_irq_domain(struct fwnode_handle *fwnode,
 	if (info->flags & MSI_FLAG_USE_DEF_CHIP_OPS)
 		pci_msi_domain_update_chip_ops(info);
 
+	info->flags |= MSI_FLAG_ACTIVATE_EARLY;
+
 	domain = msi_create_irq_domain(fwnode, info, parent);
 	if (!domain)
 		return NULL;
diff --git a/include/linux/msi.h b/include/linux/msi.h
@@ -270,6 +270,8 @@ enum {
 	MSI_FLAG_MULTI_PCI_MSI		= (1 << 2),
 	/* Support PCI MSIX interrupts */
 	MSI_FLAG_PCI_MSIX		= (1 << 3),
+	/* Needs early activate, required for PCI */
+	MSI_FLAG_ACTIVATE_EARLY		= (1 << 4),
 };
 
 int msi_domain_set_affinity(struct irq_data *data, const struct cpumask *mask,
diff --git a/kernel/irq/msi.c b/kernel/irq/msi.c
@@ -359,6 +359,17 @@ int msi_domain_alloc_irqs(struct irq_domain *domain, struct device *dev,
 		else
 			dev_dbg(dev, "irq [%d-%d] for MSI\n",
 				virq, virq + desc->nvec_used - 1);
+		/*
+		 * This flag is set by the PCI layer as we need to activate
+		 * the MSI entries before the PCI layer enables MSI in the
+		 * card. Otherwise the card latches a random msi message.
+		 */
+		if (info->flags & MSI_FLAG_ACTIVATE_EARLY) {
+			struct irq_data *irq_data;
+
+			irq_data = irq_domain_get_irq_data(domain, desc->irq);
+			irq_domain_activate_irq(irq_data);
+		}
 	}
 
 	return 0;
