diff --git a/drivers/ata/sata_sil24.c b/drivers/ata/sata_sil24.c
index 1370df6..b03bc5b 100644
--- a/drivers/ata/sata_sil24.c
+++ b/drivers/ata/sata_sil24.c
@@ -102,6 +102,7 @@ enum {
 	HOST_CTRL_STOP		= (1 << 18), /* latched PCI STOP */
 	HOST_CTRL_DEVSEL	= (1 << 19), /* latched PCI DEVSEL */
 	HOST_CTRL_REQ64		= (1 << 20), /* latched PCI REQ64 */
+	HOST_CTRL_MSIACK        = (1 << 30), /* MSI acknowledge */
 	HOST_CTRL_GLOBAL_RST	= (1 << 31), /* global reset */
 
 	/*
@@ -248,6 +249,7 @@ enum {
 				  ATA_FLAG_NCQ | ATA_FLAG_ACPI_SATA |
 				  ATA_FLAG_AN | ATA_FLAG_PMP,
 	SIL24_FLAG_PCIX_IRQ_WOC	= (1 << 24), /* IRQ loss errata on PCI-X */
+	SIL24_FLAG_MSI		= (1 << 25), /* MSI enabled */
 
 	IRQ_STAT_4PORTS		= 0xf,
 };
@@ -1144,18 +1146,22 @@ static irqreturn_t sil24_interrupt(int irq, void *dev_instance)
 	u32 status;
 	int i;
 
+	spin_lock(&host->lock);
+
+	if (host->ports[0]->flags & SIL24_FLAG_MSI)
+		writel(IRQ_STAT_4PORTS | HOST_CTRL_MSIACK,
+		       host_base + HOST_CTRL);
+
 	status = readl(host_base + HOST_IRQ_STAT);
 
 	if (status == 0xffffffff) {
 		printk(KERN_ERR DRV_NAME ": IRQ status == 0xffffffff, "
 		       "PCI fault or device removal?\n");
-		goto out;
+		goto out_unlock;
 	}
 
 	if (!(status & IRQ_STAT_4PORTS))
-		goto out;
-
-	spin_lock(&host->lock);
+		goto out_unlock;
 
 	for (i = 0; i < host->n_ports; i++)
 		if (status & (1 << i)) {
@@ -1168,8 +1174,8 @@ static irqreturn_t sil24_interrupt(int irq, void *dev_instance)
 				       ": interrupt from disabled port %d\n", i);
 		}
 
+ out_unlock:
 	spin_unlock(&host->lock);
- out:
 	return IRQ_RETVAL(handled);
 }
 
@@ -1347,6 +1353,7 @@ static int sil24_init_one(struct pci_dev *pdev, const struct pci_device_id *ent)
 	if (sata_sil24_msi && !pci_enable_msi(pdev)) {
 		dev_printk(KERN_INFO, &pdev->dev, "Using MSI\n");
 		pci_intx(pdev, 0);
+		host->ports[0]->flags |= SIL24_FLAG_MSI;
 	}
 
 	pci_set_master(pdev);