1 files changed, 21 insertions, 14 deletions

diff --git a/drivers/ata/ahci.c b/drivers/ata/ahci.c
index 5a0bf8ed649b..71e15b73513d 100644
--- a/drivers/ata/ahci.c
+++ b/drivers/ata/ahci.c
@@ -1164,9 +1164,9 @@ 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 nvec;
+        int rc, nvec;
 
         if (hpriv->flags & AHCI_HFLAG_NO_MSI)
                 goto intx;
@@ -1183,12 +1183,19 @@ static int ahci_init_interrupts(struct pci_dev *pdev, unsigned int n_ports,
         if (nvec < n_ports)
                 goto single_msi;
 
-        nvec = pci_enable_msi_range(pdev, nvec, nvec);
-        if (nvec == -ENOSPC)
+        rc = pci_enable_msi_exact(pdev, nvec);
+        if (rc == -ENOSPC)
                 goto single_msi;
-        else if (nvec < 0)
+        else if (rc < 0)
                 goto intx;
 
+        /* 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:
@@ -1232,18 +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;
         }