1 files changed, 24 insertions, 19 deletions

diff --git a/drivers/ata/ahci.c b/drivers/ata/ahci.c
index a52a5b662f35..71e15b73513d 100644
--- a/drivers/ata/ahci.c
+++ b/drivers/ata/ahci.c
@@ -1164,15 +1164,15 @@ static inline void ahci_gtf_filter_workaround(struct ata_host *host)
 #endif
 
 static int ahci_init_interrupts(struct pci_dev *pdev, unsigned int n_ports,
-			 struct ahci_host_priv *hpriv)
+				struct ahci_host_priv *hpriv)
 {
 	int rc, nvec;
 
 	if (hpriv->flags & AHCI_HFLAG_NO_MSI)
 		goto intx;
 
-	rc = pci_msi_vec_count(pdev);
-	if (rc < 0)
+	nvec = pci_msi_vec_count(pdev);
+	if (nvec < 0)
 		goto intx;
 
 	/*
@@ -1180,21 +1180,26 @@ static int ahci_init_interrupts(struct pci_dev *pdev, unsigned int n_ports,
 	 * Message mode could be enforced. In this case assume that advantage
 	 * of multipe MSIs is negated and use single MSI mode instead.
 	 */
-	if (rc < n_ports)
+	if (nvec < n_ports)
 		goto single_msi;
 
-	nvec = rc;
-	rc = pci_enable_msi_block(pdev, nvec);
-	if (rc < 0)
+	rc = pci_enable_msi_exact(pdev, nvec);
+	if (rc == -ENOSPC)
+		goto single_msi;
+	else if (rc < 0)
 		goto intx;
-	else if (rc > 0)
+
+	/* fallback to single MSI mode if the controller enforced MRSM mode */
+	if (readl(hpriv->mmio + HOST_CTL) & HOST_MRSM) {
+		pci_disable_msi(pdev);
+		printk(KERN_INFO "ahci: MRSM is on, fallback to single MSI\n");
 		goto single_msi;
+	}
 
 	return nvec;
 
 single_msi:
-	rc = pci_enable_msi(pdev);
-	if (rc)
+	if (pci_enable_msi(pdev))
 		goto intx;
 	return 1;
 
@@ -1234,18 +1239,18 @@ int ahci_host_activate(struct ata_host *host, int irq, unsigned int n_msis)
 		return rc;
 
 	for (i = 0; i < host->n_ports; i++) {
-		const char* desc;
 		struct ahci_port_priv *pp = host->ports[i]->private_data;
 
-		/* pp is NULL for dummy ports */
-		if (pp)
-			desc = pp->irq_desc;
-		else
-			desc = dev_driver_string(host->dev);
+		/* Do not receive interrupts sent by dummy ports */
+		if (!pp) {
+			disable_irq(irq + i);
+			continue;
+		}
 
-		rc = devm_request_threaded_irq(host->dev,
-			irq + i, ahci_hw_interrupt, ahci_thread_fn, IRQF_SHARED,
-			desc, host->ports[i]);
+		rc = devm_request_threaded_irq(host->dev, irq + i,
+					       ahci_hw_interrupt,
+					       ahci_thread_fn, IRQF_SHARED,
+					       pp->irq_desc, host->ports[i]);
 		if (rc)
 			goto out_free_irqs;
 	}